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Sample records for histocompatibility class ii

  1. Regulation of major histocompatibility complex class II genes

    PubMed Central

    Choi, Nancy M.; Majumder, Parimal; Boss, Jeremy M.

    2010-01-01

    Summary The major histocompatibility complex class II (MHC-II) genes are regulated at the level of transcription. Recent studies have shown that chromatin modification is critical for efficient transcription of these genes, and a number of chromatin modifying complexes recruited to MHC-II genes have been described. The MHC-II genes are segregated from each other by a series of chromatin elements, termed MHC-II insulators. Interactions between MHC-insulators and the promoters of MHC-II genes are mediated by the insulator factor CCCTC-binding protein and are critical for efficient expression. This regulatory mechanism provides a novel view of how the entire MHC-II locus is assembled architecturally and can be coordinately controlled. PMID:20970972

  2. Interactions between the Class II Transactivator and CREB Binding Protein Increase Transcription of Major Histocompatibility Complex Class II Genes

    PubMed Central

    Fontes, Joseph D.; Kanazawa, Satoshi; Jean, Dickson; Peterlin, B. Matija

    1999-01-01

    Class II major histocompatibility (class II) genes are regulated in a B-cell-specific and gamma interferon-inducible fashion. The master switch for the expression of these genes is the class II transactivator (CIITA). In this report, we demonstrate that one of the functions of CIITA is to recruit the CREB binding protein (CBP) to class II promoters. Not only functional but also specific binding interactions between CIITA and CBP were demonstrated. Moreover, a dominant negative form of CBP decreased the activity of class II promoters and levels of class II determinants on the surface of cells. Finally, the inhibition of class II gene expression by the glucocorticoid hormone could be attributed to the squelching of CBP by the glucocorticoid receptor. We conclude that CBP, a histone acetyltransferase, plays an important role in the transcription of class II genes. PMID:9858618

  3. Evolution of major histocompatibility complex class I and class II genes in the brown bear

    PubMed Central

    2012-01-01

    Background Major histocompatibility complex (MHC) proteins constitute an essential component of the vertebrate immune response, and are coded by the most polymorphic of the vertebrate genes. Here, we investigated sequence variation and evolution of MHC class I and class II DRB, DQA and DQB genes in the brown bear Ursus arctos to characterise the level of polymorphism, estimate the strength of positive selection acting on them, and assess the extent of gene orthology and trans-species polymorphism in Ursidae. Results We found 37 MHC class I, 16 MHC class II DRB, four DQB and two DQA alleles. We confirmed the expression of several loci: three MHC class I, two DRB, two DQB and one DQA. MHC class I also contained two clusters of non-expressed sequences. MHC class I and DRB allele frequencies differed between northern and southern populations of the Scandinavian brown bear. The rate of nonsynonymous substitutions (dN) exceeded the rate of synonymous substitutions (dS) at putative antigen binding sites of DRB and DQB loci and, marginally significantly, at MHC class I loci. Models of codon evolution supported positive selection at DRB and MHC class I loci. Both MHC class I and MHC class II sequences showed orthology to gene clusters found in the giant panda Ailuropoda melanoleuca. Conclusions Historical positive selection has acted on MHC class I, class II DRB and DQB, but not on the DQA locus. The signal of historical positive selection on the DRB locus was particularly strong, which may be a general feature of caniforms. The presence of MHC class I pseudogenes may indicate faster gene turnover in this class through the birth-and-death process. South–north population structure at MHC loci probably reflects origin of the populations from separate glacial refugia. PMID:23031405

  4. CD1-restricted CD4+ T cells in major histocompatibility complex class II-deficient mice

    PubMed Central

    1995-01-01

    Rather unexpectedly, major histocompatibility complex class II- deficient mice have a significant population of peripheral CD4+ T lymphocytes. We have investigated these cells at the population and clonal levels. CD4+ T lymphocytes from class II-deficient animals are thymically derived, appear early in ontogeny, exhibit the phenotype of resting memory cells, are potentially functional by several criteria, and have a diverse T cell receptor repertoire. They do not include substantially elevated numbers of NK1.1+ cells. Hybridomas derived after polyclonal stimulation of the CD4+ lymphocytes from class II- deficient animals include a subset with an unusual reactivity pattern, responding to splenocytes from many mouse strains including the strain of origin. Most members of this subset recognize the major histocompatibility complex class Ib molecule CD1; their heterogeneous reactivities and T cell receptor usage further suggest the involvement of peptides and/or highly variable posttranslational modifications. PMID:7561702

  5. Autoimmune diabetes can be induced in transgenic major histocompatibility complex class II-deficient mice

    PubMed Central

    1993-01-01

    Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease marked by hyperglycemia and mononuclear cell infiltration of insulin- producing beta islet cells. Predisposition to IDDM in humans has been linked to the class II major histocompatibility complex (MHC), and islet cells often become aberrantly class II positive during the course of the disease. We have used two recently described transgenic lines to investigate the role of class II molecules and CD4+ T cells in the onset of autoimmune insulitis. Mice that are class II deficient secondary to a targeted disruption of the A beta b gene were bred to mice carrying a transgene for the lymphocytic choriomenigitis virus (LCMV) glycoprotein (GP) targeted to the endocrine pancreas. Our results indicate that class II-deficient animals with and without the GP transgene produce a normal cytotoxic T lymphocyte response to whole LCMV. After infection with LCMV, GP-transgenic class II-deficient animals develop hyperglycemia as rapidly as their class II-positive littermates. Histologic examination of tissue sections from GP- transgenic class II-deficient animals reveals lymphocytic infiltrates of the pancreatic islets that are distinguishable from those of their class II-positive littermates only by the absence of infiltrating CD4+ T cells. These results suggest that in this model of autoimmune diabetes, CD4+ T cells and MHC class II molecules are not required for the development of disease. PMID:8101862

  6. Major histocompatibility complex class II genes and systemic sclerosis.

    PubMed

    Briggs, D; Welsh, K I

    1991-11-01

    susceptibility to the disease is conferred by neutral residues (Val, Ser, Ala), at position 57 of the DQ beta chain, while Asp at this position correlates with resistance. A similar phenomenon has been described in rheumatoid arthritis. Although DR4 in general is associated with rheumatoid arthritis, it is heterogeneous, but a subtype of DR4 which is characterised by positively charged residues at positions 70 and 71 of the beta chains is not found in patients with rheumatoid arthritis (Wordsworth B P et al, unpublished data). A similar approach applied to the study of systemic sclerosis is likely to be similarly rewarding. The precise subtyping of the class II genes and the characterisation of their associated haplotypes is therefore required for a complete understanding of the contribution of the MHC to the disease. Additional genes linked to the MHC must not be overlooked, and are relevant to associations of haplotypes with the disease. Of particular interest are the recent reports of a new class of proteins, which are determined by genes in the MHC and which are considered to play a part in the assembly of the antigen peptide/MHC molecule complex. PMID:1750798

  7. Characterization of class I- and class II-like major histocompatibility complex loci in pedigrees of North Atlantic right whales.

    PubMed

    Gillett, Roxanne M; Murray, Brent W; White, Bradley N

    2014-01-01

    North Atlantic right whales have one of the lowest levels of genetic variation at minisatellite loci, microsatellite loci, and mitochondrial control region haplotypes among mammals. Here, adaptive variation at the peptide binding region of class I and class II DRB-like genes of the major histocompatibility complex was assessed. Amplification of a duplicated region in 222 individuals revealed at least 11 class II alleles. Six alleles were assigned to the locus Eugl-DRB1 and 5 alleles were assigned to the locus Eugl-DRB2 by assessing segregation patterns of alleles from 81 parent/offspring pedigrees. Pedigree analysis indicated that these alleles segregated into 12 distinct haplotypes. Genotyping a smaller subset of unrelated individuals (n = 5 and 10, respectively) using different primer sets revealed at least 2 class II pseudogenes (with ≥ 4 alleles) and at least 3 class I loci (with ≥ 6 alleles). Class II sequences were significantly different from neutrality at peptide binding sites suggesting loci may be under the influence of balancing selection. Trans-species sharing of alleles was apparent for class I and class II sequences. Characterization of class II loci represents the first step in determining the relationship between major histocompatibility complex variability and factors affecting health and reproduction in this species.

  8. Characterization of class I- and class II-like major histocompatibility complex loci in pedigrees of North Atlantic right whales.

    PubMed

    Gillett, Roxanne M; Murray, Brent W; White, Bradley N

    2014-01-01

    North Atlantic right whales have one of the lowest levels of genetic variation at minisatellite loci, microsatellite loci, and mitochondrial control region haplotypes among mammals. Here, adaptive variation at the peptide binding region of class I and class II DRB-like genes of the major histocompatibility complex was assessed. Amplification of a duplicated region in 222 individuals revealed at least 11 class II alleles. Six alleles were assigned to the locus Eugl-DRB1 and 5 alleles were assigned to the locus Eugl-DRB2 by assessing segregation patterns of alleles from 81 parent/offspring pedigrees. Pedigree analysis indicated that these alleles segregated into 12 distinct haplotypes. Genotyping a smaller subset of unrelated individuals (n = 5 and 10, respectively) using different primer sets revealed at least 2 class II pseudogenes (with ≥ 4 alleles) and at least 3 class I loci (with ≥ 6 alleles). Class II sequences were significantly different from neutrality at peptide binding sites suggesting loci may be under the influence of balancing selection. Trans-species sharing of alleles was apparent for class I and class II sequences. Characterization of class II loci represents the first step in determining the relationship between major histocompatibility complex variability and factors affecting health and reproduction in this species. PMID:24381183

  9. Class I and class II major histocompatibility molecules play a role in bone marrow-derived macrophage development

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.; Simske, S. J.; Beharka, A. A.; Balch, S.; Luttges, M. W.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Class I and class II major histocompatibility complex (MHC) molecules play significant roles in T cell development and immune function. We show that MHCI- and MHCII-deficient mice have low numbers of macrophage precursors and circulating monocytes, as well as abnormal bone marrow cell colony-stimulating factor type 1 secretion and bone composition. We suggest that MHCI and MHCII molecules play a significant role in macrophage development.

  10. Expression of major histocompatibility complex class II and costimulatory molecules in oral carcinomas in vitro.

    PubMed

    Villarroel-Dorrego, Mariana; Speight, Paul M; Barrett, A William

    2005-01-01

    Recognition in the 1980 s that keratinocytes can express class II molecules of the Major Histocompatibility Complex (MHC) first raised the possibility that these cells might have an immunological function, and may even act as antigen presenting cells (APC). For effective T lymphocyte activation, APC require, in addition to MHC II, appropriate costimulatory signals. The aim of this study was to determine the expression of MHC class II and the co-stimulatory molecules CD40, CD80 and CD86 in keratinocytes derived from healthy oral mucosa and oral carcinomas. Using flow cytometry, it was confirmed that oral keratinocytes, switch on, expression of MHC class II molecules after stimulation with IFNgamma in vitro. All keratinocyte lines expressed CD40 constitutively; by contrast, CD80 and CD86 were universally absent. Loss of CD80 and CD86 may be one means whereby tumours escape immunological surveillance.

  11. Major histocompatibility complex class II A gene polymorphism in the striped bass

    SciTech Connect

    Hardee, J.J.; Godwin, U.; Benedetto, R.; McConnell, T.J.

    1995-02-01

    Adaptions of the polymerase chain reaction were used to isolate cDNA sequences encoding the Major histocompatibility complex (Mhc) class II A gene(s) of the striped bass (Morone saxatilis). Four complete Mhc class II A genes were cloned and sequenced from a specimen originating on the Roanoke River, North Carolina, and another three A genes from a specimen originating from the Santee-Cooper Reservoir, South Carolina, identifying a total of seven unique sequences. The sequence suggests the presence of at least two Mhc class II A loci. The extensive sequence variability observed between the seven different Mhc class II clones was concentrated in the {alpha}1 encoding domain. The encoded {alpha}2, transmembrane, and cytoplasmic regions of all seven striped bass genes correlated well with those of known vertebrate Mhc class II proteins. Overall, the striped bass sequences showed greatest similarity to the Mhc class II A genes of the zebrafish. Southern blot analysis demonstrated extensive polymorphism in the Mhc class II A genes in members of a Roanoke river-caught population of striped bass versus a lesser degree of polymorphism in an aquacultured Santee-Cooper population of striped bass. 55 refs., 5 figs., 1 tab.

  12. Major histocompatibility complex class II A gene polymorphism in the striped bass.

    PubMed

    Hardee, J J; Godwin, U; Benedetto, R; McConnell, T J

    1995-01-01

    Adaptions of the polymerase chain reaction were used to isolate cDNA sequences encoding the Major histocompatibility complex (Mhc) class II A gene(s) of the striped bass (Morone saxatilis). Four complete Mhc class II A genes were cloned and sequenced from a specimen originating in the Roanoke River, North Carolina, and another three A genes from a specimen originating from the Santee-Cooper Reservoir, South Carolina, identifying a total of seven unique sequences. The sequence suggests the presence of at least two Mhc class II A loci. The extensive sequence variability observed between the seven different Mhc class II clones was concentrated in the alpha 1 encoding domain. The encoded alpha 2, transmembrane, and cytoplasmic regions of all seven striped bass genes correlated well with those of known vertebrate Mhc class II proteins. Overall, the striped bass sequences showed greatest similarity to the Mhc class II A genes of the zebrafish. Southern blot analysis demonstrated extensive polymorphism in the Mhc class II A genes in members of a Roanoke river-caught population of striped bass versus a lesser degree of polymorphism in an aquacultured Santee-Cooper population of striped bass.

  13. Specific suppression of major histocompatibility complex class I and class II genes in astrocytes by brain-enriched gangliosides

    PubMed Central

    1993-01-01

    The effect of brain-enriched gangliosides on constitutive and cytokine- inducible expression of major histocompatibility complex (MHC) class I and II genes in cultured astrocytes was studied. Before treatment with gangliosides, astrocytes expressed constitutive MHC class I but not class II molecules, however, the expression of both MHC class I and II cell surface molecules on astrocytes was induced to high levels by interferon gamma (IFN-gamma). Constitutive and IFN-gamma-inducible expression of MHC class I and II molecules was suppressed by treatment of astrocytes with exogenous bovine brain gangliosides in a dose- dependent manner. Constitutive and induced MHC class I and II mRNA levels were also suppressed by gangliosides, indicating control through transcriptional mechanisms. This was consistent with the ability of gangliosides to suppress the binding activity of transcription factors, especially NF-kappa B-like binding activity, important for the expression of both MHC class I and II genes. These studies may be important for understanding mechanisms of central nervous system (CNS)- specific regulation of major histocompatibility molecules in neuroectodermal cells and the role of gangliosides in regulating MHC- restricted antiviral and autoimmune responses within the CNS. PMID:8376939

  14. DNase I hypersensitive sites flank the mouse class II major histocompatibility complex during B cell development.

    PubMed Central

    Carson, S

    1991-01-01

    The mouse class II major histocompatibility complex (MHC) encodes a polymorphic, multigene family important in the immune response, and is expressed mainly on mature B cells, on certain types of dendritic cells and is also inducible by gamma-interferon on antigen presenting cells. To study the regulatory elements which control this expression pattern, we have examined the chromatin structure flanking the class II MHC region, in particular during B cell differentiation. Using a panel of well-characterised mouse cell lines specific for different stages of B cell development (pre-B, B, plasma cell) as well as non-B cell lines, we have mapped the DNase I hypersensitive (DHS) sites adjacent to the mouse MHC class II region. The results presented show, for the first time that there are specific hypersensitive sites flanking the class II MHC locus during pre B cell, B cell and plasma cell stages of B cell differentiation, irrespective of the status of class II MHC expression. These hypersensitive sites are not found in T cell, fibroblast or uninduced myelomonocytic cell lines. This suggests that these DHS sites define a developmentally stable, chromatin structure, which can be used as a marker of B cell lineage commitment and may indicate that a combination of these hypersensitive sites reflect regulatory proteins involved in the immediate expression of a particular class II MHC gene or possibly control of the entire locus. Images PMID:1923768

  15. Characterisation of four major histocompatibility complex class II genes of the koala (Phascolarctos cinereus).

    PubMed

    Lau, Quintin; Jobbins, Sarah E; Belov, Katherine; Higgins, Damien P

    2013-01-01

    Major histocompatibility complex (MHC) class II molecules have an integral role in the adaptive immune response, as they bind and present antigenic peptides to T helper lymphocytes. In this study of koalas, species-specific primers were designed to amplify exon 2 of the MHC class II DA and DB genes, which contain much of the peptide-binding regions of the α and β chains. A total of two DA α1 domain variants and eight DA β1 (DAB), three DB α1 and five DB β1 variants were amplified from 20 koalas from two free-living populations from South East Queensland and the Port Macquarie region in northern New South Wales. We detected greater variation in the β1 than in the α1 domains as well as evidence of positive selection in DAB. The present study provides a springboard to future investigation of the role of MHC in disease susceptibility in koalas.

  16. Isolation and characterization of major histocompatibility complex class II B genes in cranes.

    PubMed

    Kohyama, Tetsuo I; Akiyama, Takuya; Nishida, Chizuko; Takami, Kazutoshi; Onuma, Manabu; Momose, Kunikazu; Masuda, Ryuichi

    2015-11-01

    In this study, we isolated and characterized the major histocompatibility complex (MHC) class II B genes in cranes. Genomic sequences spanning exons 1 to 4 were amplified and determined in 13 crane species and three other species closely related to cranes. In all, 55 unique sequences were identified, and at least two polymorphic MHC class II B loci were found in most species. An analysis of sequence polymorphisms showed the signature of positive selection and recombination. A phylogenetic reconstruction based on exon 2 sequences indicated that trans-species polymorphism has persisted for at least 10 million years, whereas phylogenetic analyses of the sequences flanking exon 2 revealed a pattern of concerted evolution. These results suggest that both balancing selection and recombination play important roles in the crane MHC evolution. PMID:26452363

  17. Toxic shock syndrome toxin 1 binds to major histocompatibility complex class II molecules.

    PubMed Central

    Scholl, P; Diez, A; Mourad, W; Parsonnet, J; Geha, R S; Chatila, T

    1989-01-01

    Toxic shock syndrome toxin 1 (TSST-1) is a 22-kDa exotoxin produced by strains of Staphylococcus aureus and implicated in the pathogenesis of toxic shock syndrome. In common with other staphylococcal exotoxins, TSST-1 has diverse immunological effects. These include the induction of interleukin 2 receptor expression, interleukin 2 synthesis, proliferation of human T lymphocytes, and stimulation of interleukin 1 synthesis by human monocytes. In the present study, we demonstrate that TSST-1 binds with saturation kinetics and with a dissociation constant of 17-43 nM to a single class of binding sites on human mononuclear cells. There was a strong correlation between the number of TSST-1 binding sites and the expression of major histocompatibility complex class II molecules, and interferon-gamma induced the expression of class II molecules as well as TSST-1 binding sites on human skin-derived fibroblasts. Monoclonal antibodies to HLA-DR, but not to HLA-DP or HLA-DQ, strongly inhibited TSST-1 binding. Affinity chromatography of 125I-labeled cell membranes over TSST-1-agarose resulted in the recovery of two bands of 35 kDa and 31 kDa that comigrated, respectively, with the alpha and beta chains of HLA-DR and that could be immunoprecipitated with anti-HLA-DR monoclonal antibodies. Binding of TSST-1 was demonstrated to HLA-DR and HLA-DQ L-cell transfectants. These results indicate that major histocompatibility complex class II molecules represent the major binding site for TSST-1 on human cells. Images PMID:2542966

  18. Expression Regulation of Major Histocompatibility Complex Class I and Class II Encoding Genes

    PubMed Central

    van den Elsen, Peter J.

    2011-01-01

    Major histocompatibility complex (MHC)-I and MHC-II molecules play an essential role in the immune response to pathogens by virtue of their ability to present peptides to CD8+ and CD4+ T cells, respectively. Given this critical role, MHC-I and MHC-II genes are regulated in a tight fashion at the transcriptional level by a variety of transcription factors that interact with conserved cis-acting regulatory promoter elements. In addition to the activities of these regulatory factors, modification of chromatin also plays an essential role in the efficient transcription of these genes to meet with local requirement for an effective immune response. The focus of this review is on the transcription factors that interact with conserved cis-acting promoter elements and the epigenetic mechanisms that modulate induced and constitutive expression of these MHC genes. PMID:22566838

  19. Binding and activation of major histocompatibility complex class II-deficient macrophages by staphylococcal exotoxins

    NASA Technical Reports Server (NTRS)

    Beharka, A. A.; Armstrong, J. W.; Iandolo, J. J.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

    1994-01-01

    Macrophages from C2D transgenic mice deficient in the expression of major histocompatibility complex (MHC) class II proteins were used to identify binding sites for superantigens distinct from the MHC class II molecule. Iodinated staphylococcal enterotoxins A and B (SEA and SEB) and exfoliative toxins A and B (ETA and ETB) bound to C2D macrophages in a concentration-dependent and competitive manner. All four toxins increased F-actin concentration within 30 s of their addition to C2D macrophages, indicating that signal transduction occurred in response to toxin in the absence of class II MHC. Furthermore, ETA, ETB, SEA, and, to a lesser extent, SEB induced C2D macrophages to produce interleukin 6. Several molecular species on C2D macrophages with molecular masses of 140, 97, 61, 52, 43, and 37 kDa bound SEA in immunoprecipitation experiments. These data indicate the presence of novel, functionally active toxin binding sites on murine macrophages distinct from MHC class II molecules.

  20. Major histocompatibility complex class II expression distinguishes two distinct B cell developmental pathways during ontogeny

    PubMed Central

    1994-01-01

    All mature B cells coexpress major histocompatibility complex (MHC) class II molecules, I-A and I-E, which are restriction elements required for antigen presentation to CD4+ T cells. However, the expression of class II during the early stages of B cell development has been unclear. We demonstrate here that there is a difference in the expression of class II during murine B cell development in the fetal liver and adult bone marrow (BM). These differences define two distinct B cell developmental pathways. The Fetal-type (FT) pathway is characterized by pre-B and immature IgM+ B cells generated in the fetal liver which initially lack all class II expression. In contrast, the Adult-type (AT) pathway is typified by B cells developing in the adult BM which express class II molecules from the pre-B cell stage. In vitro stromal cell cultures of sorted fetal liver and adult BM pro-B cells indicated that the difference in I-A expression during B cell development is intrinsic to the progenitors. In addition, we show that FT B cell development is not restricted to the fetal liver but occurs in the peritoneal cavities, spleens, liver, and BM of young mice up to at least 1 mo of age. The AT B cell development begins to emerge after birth but is, however, restricted to the BM environment. These findings indicate that there are two distinct B cell developmental pathways during ontogeny, each of which could contribute differentially to the immune repertoire and thus the functions of B cell subsets and lineages. PMID:7913950

  1. Stress-induced alterations in interferon production and class II histocompatibility antigen expression

    NASA Technical Reports Server (NTRS)

    Sonnenfeld, G.; Cunnick, J. E.; Armfield, A. V.; Wood, P. G.; Rabin, B. S.

    1992-01-01

    Mild electric foot-shock has been shown to be a stressor that can alter immune responses. Male Lewis rats were exposed to one session of 16 5.0-s 1.6-mA foot-shocks. Production of interferon-gamma by splenocytes in response to concanavalin-A was decreased in spleens from the shocked rats compared to control spleens. Spleen cells from rats treated with nadolol, a peripherally acting beta-adrenergic receptor antagonist, and then shocked, showed dose-dependent attenuation of the suppression of interferon-gamma production. This suggests that catecholamines mediate shock-induced suppression of interferon-gamma production. The percentage of splenic mononuclear cells expressing class II histocompatibility (Ia) antigens on their surfaces from spleens of shocked rats was determined by flow cytometry. Significantly decreased class II positive mononuclear cells were present in the spleens of shocked rats in comparison to the spleens of control rats. This may reflect an alteration of cell trafficking or decreased production of class II antigens.

  2. Engineering an intracellular pathway for major histocompatibility complex class II presentation of antigens.

    PubMed Central

    Wu, T C; Guarnieri, F G; Staveley-O'Carroll, K F; Viscidi, R P; Levitsky, H I; Hedrick, L; Cho, K R; August, J T; Pardoll, D M

    1995-01-01

    The presentation of antigenic peptides by major histocompatibility complex (MHC) class II molecules to CD4+ T cells is critical to the function of the immune system. In this study, we have utilized the sorting signal of the lysosomal-associated membrane protein LAMP-1 to target a model antigen, human papillomavirus 16 E7 (HPV-16 E7), into the endosomal and lysosomal compartments. The LAMP-1 sorting signal reroutes the antigen into the MHC class II processing pathway, resulting in enhanced presentation to CD4+ cells in vitro. In vivo immunization experiments in mice demonstrated that vaccinia containing the chimeric E7/LAMP-1 gene generated greater E7-specific lymphoproliferative activity, antibody titers, and cytotoxic T-lymphocyte activities than vaccinia containing the wild-type HPV-16 E7 gene. These results suggest that specific targeting of an antigen to the endosomal and lysosomal compartments enhances MHC class II presentation and vaccine potency. Images Fig. 2 Fig. 3 PMID:8524826

  3. Effects of major histocompatibility complex class II knockout on mouse bone mechanical properties during development

    NASA Technical Reports Server (NTRS)

    Simske, Steven J.; Bateman, Ted A.; Smith, Erin E.; Ferguson, Virginia L.; Chapes, Stephen K.

    2002-01-01

    We investigated the effect of major histocompatibility complex class II (MHC II) knockout on the development of the mouse peripheral skeleton. These C2D mice had less skeletal development at 8, 12 and 16 weeks of age compared to wild-type C57BL/6J (B6) male mice. The C2D mice had decreased femur mechanical, geometric and compositional measurements compared to wild type mice at each of these ages. C2D femur stiffness (S), peak force in 3-pt bending (Pm), and mineral mass (Min-M) were 74%, 64% and 66%, respectively, of corresponding B6 values at 8 weeks of age. Similar differences were measured at 12 weeks (for which C2D femoral S, Pm and Min-M were 71%, 72% and 73%, respectively, of corresponding B6 values) and at 16 weeks (for which C2D femoral S, Pm and Min-M were 80%, 66% and 61%, respectively, of corresponding B6 values). MHC II knockout delays the development of adult bone properties and is accompanied by lower body mass compared to wild-type controls.

  4. Persistent Ehrlichia chaffeensis infection occurs in the absence of functional major histocompatibility complex class II genes

    NASA Technical Reports Server (NTRS)

    Ganta, Roman Reddy; Wilkerson, Melinda J.; Cheng, Chuanmin; Rokey, Aaron M.; Chapes, Stephen K.

    2002-01-01

    Human monocytic ehrlichiosis is an emerging tick-borne disease caused by the rickettsia Ehrlichia chaffeensis. We investigated the impact of two genes that control macrophage and T-cell function on murine resistance to E. chaffeensis. Congenic pairs of wild-type and toll-like receptor 4 (tlr4)- or major histocompatibility complex class II (MHC-II)-deficient mice were used for these studies. Wild-type mice cleared the infection within 2 weeks, and the response included macrophage activation and the synthesis of E. chaffeensis-specific Th1-type immunoglobulin G response. The absence of a functional tlr4 gene depressed nitric oxide and interleukin 6 secretion by macrophages and resulted in short-term persistent infections for > or =30 days. In the absence of MHC-II alleles, E. chaffeensis infections persisted throughout the entire 3-month evaluation period. Together, these data suggest that macrophage activation and cell-mediated immunity, orchestrated by CD4(+) T cells, are critical for conferring resistance to E. chaffeensis.

  5. Major histocompatibility complex class II compatibility, but not class I, predicts mate choice in a bird with highly developed olfaction.

    PubMed

    Strandh, Maria; Westerdahl, Helena; Pontarp, Mikael; Canbäck, Björn; Dubois, Marie-Pierre; Miquel, Christian; Taberlet, Pierre; Bonadonna, Francesco

    2012-11-01

    Mate choice for major histocompatibility complex (MHC) compatibility has been found in several taxa, although rarely in birds. MHC is a crucial component in adaptive immunity and by choosing an MHC-dissimilar partner, heterozygosity and potentially broad pathogen resistance is maximized in the offspring. The MHC genotype influences odour cues and preferences in mammals and fish and hence olfactory-based mate choice can occur. We tested whether blue petrels, Halobaena caerulea, choose partners based on MHC compatibility. This bird is long-lived, monogamous and can discriminate between individual odours using olfaction, which makes it exceptionally well suited for this analysis. We screened MHC class I and II B alleles in blue petrels using 454-pyrosequencing and quantified the phylogenetic, functional and allele-sharing similarity between individuals. Partners were functionally more dissimilar at the MHC class II B loci than expected from random mating (p = 0.033), whereas there was no such difference at the MHC class I loci. Phylogenetic and non-sequence-based MHC allele-sharing measures detected no MHC dissimilarity between partners for either MHC class I or II B. Our study provides evidence of mate choice for MHC compatibility in a bird with a high dependency on odour cues, suggesting that MHC odour-mediated mate choice occurs in birds.

  6. Cloning of the major histocompatibility complex class II promoter binding protein affected in a hereditary defect in class II gene regulation.

    PubMed Central

    Reith, W; Barras, E; Satola, S; Kobr, M; Reinhart, D; Sanchez, C H; Mach, B

    1989-01-01

    The regulation of major histocompatibility complex class II gene expression is directly involved in the control of normal and abnormal immune responses. In humans, HLA-DR, -DQ, and -DP class II heterodimers are encoded by a family of alpha- and beta-chain genes clustered in the major histocompatibility complex. Their expression is developmentally controlled and normally restricted to certain cell types. This control is mediated by cis-acting sequences in class II promoters and by trans-acting regulatory factors. Several nuclear proteins bind to class II promoter sequences. In a form of hereditary immunodeficiency characterized by a defect in a trans-acting regulatory factor controlling class II gene transcription, we have observed that one of these nuclear factors (RF-X) does not bind to its target sequence (the class II X box). A cDNA encoding RF-X was isolated by screening a phage expression library with an X-box binding-site probe. The recombinant protein has the binding specificity of RF-X, including a characteristic gradient of affinity for the X boxes of HLA-DR, -DP, and -DQ promoters. RF-X mRNA is present in the regulatory mutants, indicating a defect in the synthesis of a functional form of the RF-X protein. Images PMID:2498880

  7. Major histocompatibility complex haplotypes and class II genes in non-Jewish patients with pemphigus vulgaris

    SciTech Connect

    Ahmed, A.R. Center for Blood Research, Boston, MA American Red Cross Blood Services-Northeast Region, Dedham, MA ); Wagner, R.; Khatri, K.; Notani, G.; Awdeh, Z.; Alper, C.A. ); Yunis, E.J. American Red Cross Blood Services-Northeast Region, Dedham, MA )

    1991-06-01

    Previous studies demonstrated that HLA-DR4 was markedly increased among Ashkenazi Jewish patients with pemphigus vulgaris (PV), almost entirely as the common Jewish extended haplotype (HLA-B38, SC21, DR4, DQw8) or as the haplotype HLA-B35, SC31, DR4, DQw8, and that HLA-DR4, DQw8 was distributed among patients in a manner consistent with dominant expression of a class II (D-region or D-region-linked) susceptibility gene. In the present study of major histocompatibility complex (MHC) halotypes in 25 non-Jewish PV patients, DR4, DQw8 was found in 12 of the patients and DRw6, DQw5 was found in 15. Only 3 patients had neither. The non-Jewish patients were of more Southern European extraction than our controls. This suggests that there are two major MHC susceptibility alleles in American patients with PV. The more ancient apparently arose on a haplotype in the Jews, HLA-B38(35), SC21(SC31), DR4, DQw8, and spread to other populations largely as D-region segments. The other arose in or near Italy on the haplotype HLA-Bw55, SB45, DRw14, DQw5 amd has also partially fragmented so that many patients carry only DRw14, DQw5. The available data do not permit the specific localization of either the DR4, DQw8-or the DRw14, DQw5-linked susceptibility genes.

  8. Staphylococcus-mediated T-cell activation and spontaneous natural killer cell activity in the absence of major histocompatibility complex class II molecules

    NASA Technical Reports Server (NTRS)

    Chapes, S. K.; Hoynowski, S. M.; Woods, K. M.; Armstrong, J. W.; Beharka, A. A.; Iandolo, J. J.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    We used major histocompatibility complex class II antigen-deficient transgenic mice to show that in vitro natural killer cell cytotoxicity and T-cell activation by staphylococcal exotoxins (superantigens) are not dependent upon the presence of major histocompatibility complex class II molecules. T cells can be activated by exotoxins in the presence of exogenously added interleukin 1 or 2 or in the presence of specific antibody without exogenously added cytokines.

  9. Staphylococcus-mediated T-cell activation and spontaneous natural killer cell activity in the absence of major histocompatibility complex class II molecules.

    PubMed Central

    Chapes, S K; Hoynowski, S M; Woods, K M; Armstrong, J W; Beharka, A A; Iandolo, J J

    1993-01-01

    We used major histocompatibility complex class II antigen-deficient transgenic mice to show that in vitro natural killer cell cytotoxicity and T-cell activation by staphylococcal exotoxins (superantigens) are not dependent upon the presence of major histocompatibility complex class II molecules. T cells can be activated by exotoxins in the presence of exogenously added interleukin 1 or 2 or in the presence of specific antibody without exogenously added cytokines. PMID:8359928

  10. Distribution and origin of bovine major histocompatibility complex class II DQA1 genes in Japan.

    PubMed

    Takeshima, S; Chen, S; Miki, M; Kado, M; Aida, Y

    2008-09-01

    We sequenced the major histocompatibility complex (MHC) class II DQA1 gene in 352 Japanese cattle (95 Japanese Black, 91 Holstein, 102 Japanese Shorthorn and 64 Jersey cattle) using a new sequence-based typing method. In total, 19 bovine MHC (BoLA)-DQA1 alleles, of which two were novel alleles, were detected. The Holstein, Jersey, Japanese Shorthorn and Japanese Black breeds had 13, 12, 10 and 15 alleles, respectively. The dendrogram that was constructed by the neighbor-joining method on the basis of the DQA1 gene allele frequencies of the four Japanese cattle breeds showed that the Holstein and Japanese Black breeds were closest to each other, with Jersey being farther from these two breeds than Japanese Shorthorn. In addition, Wu-Kabat analysis showed that the DQA1 alleles of the Holstein and Japanese Black were the most and least polymorphic, respectively. Phylogenetic analyses indicated that the DQA1 gene of Bovidae such as cattle, sheep, bison and goat were more similar to pig SLA-DQA genes than to human HLA-DQA1 and dog DLA-DQA genes. The cattle, goat, bison, sheep, human and pig DQA1 molecules had similar rates of amino acid sequence polymorphism, but the distribution of their polymorphic residues differed from that in the dog DQA1 protein. However, the Bovidae DQA1 molecule had more polymorphic residues than the human, pig and dog DQA molecules at two regions, namely positions 52-53 and 65-66. This indicates that the Bovidae DQA1 locus is more polymorphic than the DQA loci of other species.

  11. Cooperativity between the J and S elements of class II major histocompatibility complex genes as enhancers in normal and class II- negative patient and mutant B cell lines

    PubMed Central

    1995-01-01

    The class II major histocompatibility complex genes all contain in their proximal promoters three cis-elements called S, X, and Y that are conserved in both sequence and position, and a fourth element, J, conserved in sequence but not in position. J, X, and Y and, to some extent, S, have been shown to be functionally important in regulation of expression of these genes. In the present study, a protein factor that binds cooperatively to the S plus J elements of the promoter of the class II major histocompatibility complex gene DPA has been detected. Moreover, functional cooperativity between S and J in activation of the enhancerless -40 interferon-beta (-40 IFN-beta) promoter has been demonstrated. Finally, the latter assay appears to subdivide complementation group A of class II negative human B cell lines that includes both mutants generated in vitro and cells from patients with the bare lymphocyte syndrome (type II). In three of these cell lines, the enhancerless -40 IFN-beta promoter containing the S plus J elements was functionally active, while in the others it was inactive. PMID:7790817

  12. Major histocompatibility complex haplotypes and class II genes in non-Jewish patients with pemphigus vulgaris.

    PubMed Central

    Ahmed, A R; Wagner, R; Khatri, K; Notani, G; Awdeh, Z; Alper, C A; Yunis, E J

    1991-01-01

    Previous studies demonstrated that HLA-DR4 was markedly increased among Ashkenazi Jewish patients with pemphigus vulgaris (PV), almost entirely as the common Jewish extended haplotype [HLA-B38, SC21, DR4, DQw8] or as the haplotype HLA-B35, SC31, DR4, DQw8, and that HLA-DR4, DQw8 was distributed among patients in a manner consistent with dominant expression of a class II (D-region or D-region-linked) susceptibility gene. In the present study of major histocompatibility complex (MHC) haplotypes in 25 non-Jewish PV patients, DR4, DQw8 was found in 12 of the patients and DRw6, DQw5 was found in 15. Only 3 patients had neither. Only 1 of the DR4, DQw8 haplotypes was [HLA-B38, SC21, DR4, DQw8] and 2 were HLA-B35, SC31, DR4, DQw8; most were the presumed fragments (SC31, DR4, DQw8) or (SC21, DR4, DQw8) or DR4, DQw8 with some other complotype. Of the patients with DRw6, DQw5, all were DRw14, DQw5, and 6 had a rare Caucasian haplotype, HLA-Bw55, SB45, DRw14, DQw5. Four of 6 of these were found in patients of Italian extraction, as was the 1 normal example. The non-Jewish patients were of more Southern European extraction than our controls. This suggests that there are two major MHC susceptibility alleles in American patients with PV. The more ancient apparently arose on a haplotype in the Jews, HLA-B38(35), SC21(SC31), DR4, DQw8, and spread to other populations largely as D-region segments. The other arose in or near Italy on the haplotype HLA-Bw55, SB45, DRw14, DQw5 and has also partially fragmented so that many patients carry only DRw14, DQw5. The available data do not permit the specific localization of either the DR4, DQw8- or the DRw14, DQw5-linked susceptibility genes. Images PMID:1675792

  13. Role of chain pairing for the production of functional soluble IA major histocompatibility complex class II molecules

    PubMed Central

    1996-01-01

    Structural studies of cellular receptor molecules involved in immune recognition require the production of large quantities of the extracellular domains of these glycoproteins. The murine major histocompatibility complex (MHC) class II-restricted response has been extensively studied by functional means, but the engineering and purification of the native, empty form of the most-studied murine MHC class II molecule, IA, has been difficult to achieve. IA molecules, which are the murine equivalent of human histocompatibility leukocyte antigen-DQ molecules, have a low efficiency of chain pairing, which results in poor transport to the cell surface and in the appearance of mixed isotype pairs. We have engineered soluble IA molecules whose pairing has been forced by the addition of leucine zipper peptide dimers at their COOH-terminus. The molecules are secreted "empty" into the extracellular medium and can be loaded with single peptide after purification. These IA molecules have been expressed in milligram quantity for crystallization as well as for activation of T cells and measurement of MHC class II-T cell receptor interactions. PMID:8642319

  14. Species specificity and augmentation of responses to class II major histocompatibility complex molecules in human CD4 transgenic mice

    PubMed Central

    1992-01-01

    Murine T cell responses to human class II major histocompatibility complex (MHC) molecules were shown to be a minimum of 20-70-fold lower than responses to allogeneic molecules. Transgenic mice expressing slightly below normal (75-95%) or very high (250-380%) cell surface levels of human CD4 were utilized to determine whether this was due to a species-specific interaction between murine CD4 and class II molecules. Human CD4 was shown to function in signal transduction events in murine T cells based on the ability of anti-human CD4 antibody to synergize with suboptimal doses of anti-murine CD3 antibody in stimulating T cell proliferation. In mice expressing lower levels of human CD4, T cell responses to human class II molecules were enhanced up to threefold, whereas allogeneic responses were unaltered. In mice expressing high levels of human CD4, responses to human class II molecules were enhanced at least 10-fold, whereas allogeneic responses were between one and three times the level of normal responses. The relatively greater enhancement of the response to human class II molecules in both lines argues for a preferential interaction between human CD4 and human class II molecules. In mice expressing lower levels of human CD4, responses to human class II molecules were blocked by antibodies to CD4 of either species, indicating participation by both molecules. In mice expressing high levels of human CD4, responses to both human and murine class II molecules were almost completely blocked with anti-human CD4 antibody, whereas anti-murine CD4 antibody had no effect. However, anti-murine CD4 continued to synergize with anti-CD3 in stimulating T cell proliferation in these mice. Thus, overexpression of human CD4 selectively impaired the ability of murine CD4 to assist in the process of antigen recognition. The ability of human CD4 to support a strong allogeneic response under these conditions indicates that this molecule can interact with murine class II molecules to a

  15. Organization and characteristics of the major histocompatibility complex class II region in the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)

    PubMed Central

    Ruan, Rui; Ruan, Jue; Wan, Xiao-Ling; Zheng, Yang; Chen, Min-Min; Zheng, Jin-Song; Wang, Ding

    2016-01-01

    Little is known about the major histocompatibility complex (MHC) in the genome of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) (YFP) or other cetaceans. In this study, a high-quality YFP bacterial artificial chromosome (BAC) library was constructed. We then determined the organization and characterization of YFP MHC class II region by screening the BAC library, followed by sequencing and assembly of positive BAC clones. The YFP MHC class II region consists of two segregated contigs (218,725 bp and 328,435 bp respectively) that include only eight expressed MHC class II genes, three pseudo MHC genes and twelve non-MHC genes. The YFP has fewer MHC class II genes than ruminants, showing locus reduction in DRB, DQA, DQB, and loss of DY. In addition, phylogenic and evolutionary analyses indicated that the DRB, DQA and DQB genes might have undergone birth-and-death evolution, whereas the DQB gene might have evolved under positive selection in cetaceans. These findings provide an essential foundation for future work, such as estimating MHC genetic variation in the YFP or other cetaceans. This work is the first report on the MHC class II region in cetaceans and offers valuable information for understanding the evolution of MHC genome in cetaceans. PMID:26932528

  16. Organization and characteristics of the major histocompatibility complex class II region in the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis).

    PubMed

    Ruan, Rui; Ruan, Jue; Wan, Xiao-Ling; Zheng, Yang; Chen, Min-Min; Zheng, Jin-Song; Wang, Ding

    2016-01-01

    Little is known about the major histocompatibility complex (MHC) in the genome of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) (YFP) or other cetaceans. In this study, a high-quality YFP bacterial artificial chromosome (BAC) library was constructed. We then determined the organization and characterization of YFP MHC class II region by screening the BAC library, followed by sequencing and assembly of positive BAC clones. The YFP MHC class II region consists of two segregated contigs (218,725 bp and 328,435 bp respectively) that include only eight expressed MHC class II genes, three pseudo MHC genes and twelve non-MHC genes. The YFP has fewer MHC class II genes than ruminants, showing locus reduction in DRB, DQA, DQB, and loss of DY. In addition, phylogenic and evolutionary analyses indicated that the DRB, DQA and DQB genes might have undergone birth-and-death evolution, whereas the DQB gene might have evolved under positive selection in cetaceans. These findings provide an essential foundation for future work, such as estimating MHC genetic variation in the YFP or other cetaceans. This work is the first report on the MHC class II region in cetaceans and offers valuable information for understanding the evolution of MHC genome in cetaceans. PMID:26932528

  17. Selection and Trans-Species Polymorphism of Major Histocompatibility Complex Class II Genes in the Order Crocodylia

    PubMed Central

    Jaratlerdsiri, Weerachai; Isberg, Sally R.; Higgins, Damien P.; Miles, Lee G.; Gongora, Jaime

    2014-01-01

    Major Histocompatibility Complex (MHC) class II genes encode for molecules that aid in the presentation of antigens to helper T cells. MHC characterisation within and between major vertebrate taxa has shed light on the evolutionary mechanisms shaping the diversity within this genomic region, though little characterisation has been performed within the Order Crocodylia. Here we investigate the extent and effect of selective pressures and trans-species polymorphism on MHC class II α and β evolution among 20 extant species of Crocodylia. Selection detection analyses showed that diversifying selection influenced MHC class II β diversity, whilst diversity within MHC class II α is the result of strong purifying selection. Comparison of translated sequences between species revealed the presence of twelve trans-species polymorphisms, some of which appear to be specific to the genera Crocodylus and Caiman. Phylogenetic reconstruction clustered MHC class II α sequences into two major clades representing the families Crocodilidae and Alligatoridae. However, no further subdivision within these clades was evident and, based on the observation that most MHC class II α sequences shared the same trans-species polymorphisms, it is possible that they correspond to the same gene lineage across species. In contrast, phylogenetic analyses of MHC class II β sequences showed a mixture of subclades containing sequences from Crocodilidae and/or Alligatoridae, illustrating orthologous relationships among those genes. Interestingly, two of the subclades containing sequences from both Crocodilidae and Alligatoridae shared specific trans-species polymorphisms, suggesting that they may belong to ancient lineages pre-dating the divergence of these two families from the common ancestor 85–90 million years ago. The results presented herein provide an immunogenetic resource that may be used to further assess MHC diversity and functionality in Crocodylia. PMID:24503938

  18. Identification and mapping of two divergent, unlinked major histocompatibility complex class II B genes in Xiphophorus fishes.

    PubMed Central

    McConnell, T J; Godwin, U B; Norton, S F; Nairn, R S; Kazianis, S; Morizot, D C

    1998-01-01

    We have isolated two major histocompatibility complex (MHC) class II B genes from the inbred fish strain Xiphophorus maculatus Jp 163 A. We mapped one of these genes, designated here as DXB, to linkage group III, linked to a malic enzyme locus, also syntenic with human and mouse MHC. Comparison of genomic and cDNA clones shows the gene consists of six exons and five introns. The encoded beta1 domain has three amino acids deleted and a cytoplasmic tail nine amino acids longer than in other teleost class II beta chains, more similar to HLA-DRB, clawed frog Xela-F3, and nurse shark Gici-B. Key residues for disulfide bonds, glycosylation, and interaction with alpha chains are conserved. These same features are also present in a swordtail (Xiphophorus helleri) genomic DXB PCR clone. A second type of class II B clone was amplified by PCR from X. maculatus and found to be orthologous to class II genes identified in other fishes. This DAB-like gene is 63% identical to the X. maculatus DXB sequence in the conserved beta2-encoding exon and was mapped to new unassigned linkage group LG U24. The DXB gene, then, represents an unlinked duplicated locus not previously identified in teleosts. PMID:9691047

  19. Antigen capture and major histocompatibility class II compartments of freshly isolated and cultured human blood dendritic cells

    PubMed Central

    1995-01-01

    Dendritic cells (DC) represent potent antigen-presenting cells for the induction of T cell-dependent immune responses. Previous work on antigen uptake and presentation by human DC is based largely on studies of blood DC that have been cultured for various periods of time before analysis. These cultured cells may therefore have undergone a maturation process from precursors that have different capacities for antigen capture and presentation. We have now used immunoelectron microscopy and antigen presentation assays to compare freshly isolated DC (f-DC) and cultured DC (c-DC). f-DC display a round appearance, whereas c-DC display characteristic long processes. c-DC express much more cell surface major histocompatibility complex (MHC) class II than f-DC. The uptake of colloidal gold-labeled bovine serum albumin (BSA), however, is greater in f-DC, as is the presentation of 65-kD heat shock protein to T cell clones. The most striking discovery is that the majority of MHC class II molecules in both f-DC and c-DC occur in intracellular vacuoles with a complex shape (multivesicular and multilaminar). These MHC class II enriched compartments (MIIC) represent the site to which BSA is transported within 30 min. Although MIIC appear as more dense structures with less MHC class II molecules in f-DC than c-DC, the marker characteristics are very similar. The MIIC in both types of DC are acidic, contain invariant chain, and express the recently described HLA-DM molecule that can contribute to antigen presentation. CD19+ peripheral blood B cells have fewer MIIC and surface MHC class II expression than DCs, while monocytes had low levels of MIIC and surface MHC class II. These results demonstrate in dendritic cells the elaborate development of MIIC expressing several of the components that are required for efficient antigen presentation. PMID:7790816

  20. Major Histocompatibility Class II Pathway Is Not Required for the Development of Nonalcoholic Fatty Liver Disease in Mice.

    PubMed

    Willemin, Gilles; Roger, Catherine; Bauduret, Armelle; Minehira, Kaori

    2013-01-01

    Single-nucleotide polymorphisms within major histocompatibility class II (MHC II) genes have been associated with an increased risk of drug-induced liver injury. However, it has never been addressed whether the MHC II pathway plays an important role in the development of nonalcoholic fatty liver disease, the most common form of liver disease. We used a mouse model that has a complete knockdown of genes in the MHC II pathway (MHCII(Δ/Δ)). Firstly we studied the effect of high-fat diet-induced hepatic inflammation in these mice. Secondly we studied the development of carbon-tetra-chloride- (CCl4-) induced hepatic cirrhosis. After the high-fat diet, both groups developed obesity and hepatic steatosis with a similar degree of hepatic inflammation, suggesting no impact of the knockdown of MHC II on high-fat diet-induced inflammation in mice. In the second study, we confirmed that the CCl4 injection significantly upregulated the MHC II genes in wild-type mice. The CCl4 treatment significantly induced genes related to the fibrosis formation in wild-type mice, whereas this was lower in MHCII(Δ/Δ) mice. The liver histology, however, showed no detectable difference between groups, suggesting that the MHC II pathway is not required for the development of hepatic fibrosis induced by CCl4.

  1. Major histocompatibility complex class II antigens are required for both cytokine production and proliferation induced by mercuric chloride in vitro.

    PubMed

    Hu, H; Möller, G; Abedi-Valugerdi, M

    1997-10-01

    Autoimmune diseases induced by mercuric chloride are genetically determined, at least one gene being major histocompatibility complex (MHC)-linked. Previously, we showed that in vitro mercury stimulation induced a high proliferative response in lymphocytes from susceptible mice (high-responders) and that the proliferative response could be restored in lymphocytes from low-responders by pretreating the cells with mercury. We also found that the continuous presence of mercury induced IL-2 and IFN-gamma production, while pretreatment with mercury induced IL-4 production. In this study, we showed that anti-MHC class II monoclonal antibodies blocked both the mercury-induced proliferative responses in lymphocytes from high-responders and the restored proliferative responses in low-responders. In addition, anti-MHC class II antibodies also inhibited the mercury-induced IL-2, IFN-gamma and IL-4 cytokine production in vitro. The results demonstrate that MHC class II antigens directly participate in mercury-induced cytokine production and cell activation, and are required at the onset of the initiation.

  2. Regulation of major histocompatibility complex class II synthesis by interleukin-10

    PubMed Central

    Morel, Anne-Sophie; Coulton, Gary; Londei, Marco

    2002-01-01

    We have shown previously that interleukin-10 (IL-10) blocks the development and T-cell stimulatory capacity of human monocyte-derived dendritic cells, without apparently down-regulating the surface expression of co-stimulatory molecules or human leucocyte antigen (HLA) molecules. In the majority of donors (60%), the cell surface levels of HLA-DR actually increased upon IL-10 treatment. Here we have shown that IL-10 does not regulate HLA-DR transcription as assessed by polymerase chain reation. Epifluorescence microscopy analysis showed that IL-10 primarily increased the intracellular pool of HLA-DR. In fact, IL-10 directly increased HLA-DR protein synthesis. However, IL-10 did not significantly alter the synthesis of invariant chain (Ii), which plays a crucial role in the assembly, transport and loading of newly formed HLA class II molecules, nor the amount of Ii reaching the cell-surface. In contrast, IL-10 increased the amount of HLA-DR-bound Iip33 shortly after the HLA-DR complex assembly. We postulate that, upon IL-10 treatment, immature Ii-associated HLA II molecules can still transit to the cell surface as they do in immature dendritic cells and recycle to the intracellular space, where they accumulate. A higher proportion of Ii-associated HLA-DR, coupled to increased membrane recycling, may contribute to the lower T-cell stimulatory capacity of IL-10-treated dendritic cells. PMID:12047752

  3. Crystal Structure of Staphylococcal Enterotoxin I (SEI) in Complex with a Human Major Histocompatibility Complex Class II Molecule*

    PubMed Central

    Fernández, Marisa M.; Guan, Rongjin; Swaminathan, Chittoor P.; Malchiodi, Emilio L.; Mariuzza, Roy A.

    2009-01-01

    Superantigens are bacterial or viral proteins that elicit massive T cell activation through simultaneous binding to major histocompatibility complex (MHC) class II and T cell receptors. This activation results in uncontrolled release of inflammatory cytokines, causing toxic shock. A remarkable property of superantigens, which distinguishes them from T cell receptors, is their ability to interact with multiple MHC class II alleles independently of MHC-bound peptide. Previous crystallographic studies have shown that staphylococcal and streptococcal superantigens belonging to the zinc family bind to a high affinity site on the class II β-chain. However, the basis for promiscuous MHC recognition by zinc-dependent superantigens is not obvious, because the β-chain is polymorphic and the MHC-bound peptide forms part of the binding interface. To understand how zinc-dependent superantigens recognize MHC, we determined the crystal structure, at 2.0 Å resolution, of staphylococcal enterotoxin I bound to the human class II molecule HLA-DR1 bearing a peptide from influenza hemagglutinin. Interactions between the superantigen and DR1 β-chain are mediated by a zinc ion, and 22% of the buried surface of peptide·MHC is contributed by the peptide. Comparison of the staphylococcal enterotoxin I·peptide·DR1 structure with ones determined previously revealed that zinc-dependent superantigens achieve promiscuous binding to MHC by targeting conservatively substituted residues of the polymorphic β-chain. Additionally, these superantigens circumvent peptide specificity by engaging MHC-bound peptides at their conformationally conserved N-terminal regions while minimizing sequence-specific interactions with peptide residues to enhance cross-reactivity. PMID:16829512

  4. Stereospecific alignment of the X and Y elements is required for major histocompatibility complex class II DRA promoter function.

    PubMed Central

    Vilen, B J; Cogswell, J P; Ting, J P

    1991-01-01

    The regulatory mechanisms controlling expression of the major histocompatibility complex (MHC) class II genes involve several cis-acting DNA elements, including the X and Y boxes. These two elements are conserved within all murine and human class II genes and are required for accurate and efficient transcription from MHC class II promoters. Interestingly, the distance between the X and Y elements is also evolutionarily conserved at 18 to 20 bp. To investigate the function of the invariant spacing in the human MHC class II gene, HLA-DRA, we constructed a series of spacing mutants which alters the distance between the X and Y elements by integral and half-integral turns of the DNA helix. Transient transfection of the spacing constructs into Raji cells revealed that inserting integral turns of the DNA helix (+20 and +10 bp) did not reduce promoter activity, while inserting or deleting half-integral turns of the DNA helix (+15, +5, and -5 bp) drastically reduced promoter activity. The loss of promoter function in these half-integral turn constructs was due neither to the inability of the X and Y elements to bind proteins nor to improper binding of the X- and Y-box-binding proteins. These data indicate that the X and Y elements must be aligned on the same side of the DNA helix to ensure normal function. This requirement for stereospecific alignment strongly suggests that the X- and Y-box-binding proteins either interact directly or are components of a larger transcription complex which assembles on one face of the DNA double helix. Images PMID:1901941

  5. Zinc Induces Dimerization of the Class II Major Histocompatibility Complex Molecule That Leads to Cooperative Binding to a Superantigen

    SciTech Connect

    Li,H.; Zhao, Y.; Guo, Y.; Li, Z.; Eislele, L.; Mourad, W.

    2007-01-01

    Dimerization of class II major histocompatibility complex (MHC) plays an important role in the MHC biological function. Mycoplasma arthritidis-derived mitogen (MAM) is a superantigen that can activate large fractions of T cells bearing specific T cell receptor V{beta} elements. Here we have used structural, sedimentation, and surface plasmon resonance detection approaches to investigate the molecular interactions between MAM and the class II MHC molecule HLA-DR1 in the context of a hemagglutinin peptide-(306-318) (HA). Our results revealed that zinc ion can efficiently induce the dimerization of the HLA-DR1/HA complex. Because the crystal structure of the MAM/HLA-DR1/hemagglutinin complex in the presence of EDTA is nearly identical to the structure of the complex crystallized in the presence of zinc ion, Zn{sup 2+} is evidently not directly involved in the binding between MAM and HLA-DR1. Sedimentation and surface plasmon resonance studies further revealed that MAM binds the HLA-DR1/HA complex with high affinity in a 1:1 stoichiometry, in the absence of Zn{sup 2+}. However, in the presence of Zn{sup 2+}, a dimerized MAM/HLA-DR1/HA complex can arise through the Zn{sup 2+}-induced DR1 dimer. In the presence of Zn{sup 2+}, cooperative binding of MAM to the DR1 dimer was also observed.

  6. cDNA cloning and genetic polymorphism of the swine major histocompatibility complex (SLA) class II DMA gene.

    PubMed

    Ando, A; Kawata, H; Murakami, T; Shigenari, A; Shiina, T; Sada, M; Tsuji, T; Toriu, A; Nakanishi, Y; Mitsuhashi, T; Sekikawa, K; Inoko, H

    2001-04-01

    cDNA clones corresponding to the swine histocompatibility complex (SLA: swine leucocyte antigen)-DM alpha chain were isolated using the polymerase chain reaction (PCR) products from the third exon in the human HLA-DMA gene as a probe. Amino acid comparative analysis revealed that these clones were more closely related to the bovine and human DMA genes than to the other swine class II genes alpha chain genes, DRA, DQA and DOA. These results suggest that the SLA-DMA gene is expressed and may function, like HLA-DM, as an important modulator in class II restricted antigen processing in swine. Furthermore, based on the sequences and PCR-restriction fragment length polymorphism (PCR-RFLP) patterns in the SLA-DMA gene, no allelic variation was recognized in the second exon, but five allelic variations were recognized in the third exon in five different breeds of swine. These DMA alleles were defined by variation at four nucleotide positions. Two of these alleles resulted in an amino acid substitution. These results suggest that SLA-DMA has little polymorphism as observed in HLA-DMA and mouse H2-Ma.

  7. Major histocompatibility complex class II molecules can protect from diabetes by positively selecting T cells with additional specificities.

    PubMed

    Lühder, F; Katz, J; Benoist, C; Mathis, D

    1998-02-01

    Insulin-dependent diabetes is heavily influenced by genes encoded within the major histocompatibility complex (MHC), positively by some class II alleles and negatively by others. We have explored the mechanism of MHC class II-mediated protection from diabetes using a mouse model carrying the rearranged T cell receptor (TCR) transgenes from a diabetogenic T cell clone derived from a nonobese diabetic mouse. BDC2.5 TCR transgenics with C57Bl/6 background genes and two doses of the H-2(g7) allele exhibited strong insulitis at approximately 3 wk of age and most developed diabetes a few weeks later. When one of the H-2(g7) alleles was replaced by H-2(b), insulitis was still severe and only slightly delayed, but diabetes was markedly inhibited in both its penetrance and time of onset. The protective effect was mediated by the Abetab gene, and did not merely reflect haplozygosity of the Abetag7 gene. The only differences we observed in the T cell compartments of g7/g7 and g7/b mice were a decrease in CD4(+) cells displaying the transgene-encoded TCR and an increase in cells expressing endogenously encoded TCR alpha-chains. When the synthesis of endogenously encoded alpha-chains was prevented, the g7/b animals were no longer protected from diabetes. g7/b mice did not have a general defect in the production of Ag7-restricted T cells, and antigen-presenting cells from g7/b animals were as effective as those from g7/g7 mice in stimulating Ag7-restricted T cell hybridomas. These results argue against mechanisms of protection involving clonal deletion or anergization of diabetogenic T cells, or one depending on capture of potentially pathogenic Ag7-restricted epitopes by Ab molecules. Rather, they support a mechanism based on MHC class II-mediated positive selection of T cells expressing additional specificities. PMID:9449718

  8. Engagement of major histocompatibility complex class I and class II molecules up-regulates intercellular adhesion of human B cells via a CD11/CD18-independent mechanism.

    PubMed

    Alcover, A; Juillard, V; Acuto, O

    1992-02-01

    We have studied the role of major histocompatibility complex (MHC) molecules in the regulation of intercellular adhesion of human B cells. We found that molecules able to bind to MHC class II molecules, such as monoclonal antibodies or staphylococcal enterotoxins, induced rapid and sustained homotypic adhesion of Epstein-Barr virus (EBV)-transformed B cell lines as well as peripheral blood B lymphocytes. Moreover, anti-MHC class I monoclonal antibodies also stimulated intercellular adherence. Adhesion induced upon MHC engagement was faster and stronger than that triggered by phorbol esters. It needed active metabolism, but divalent cations were not required. Monoclonal antibodies directed against LFA-1 (CD11a/CD18) or its ligand ICAM-1 (CD54) did not inhibit MHC class II-induced homotypic adhesion of various EBV-transformed B cell lines, nor of a variant of the B cell line Raji expressing very low LFA-1 surface levels. Moreover, EBV-transformed B cells from a severe lymphocyte adhesion deficiency patient, lacking surface CD11/CD18, also aggregated in response to anti-MHC class I or class II monoclonal antibodies. Together these data indicate that engagement of MHC molecules may transduce signals to B cells resulting in up-regulation of intercellular adhesion, via an LFA-1-independent mechanism. This may play a role in the stabilization of T cell/antigen-presenting cell conjugates at the moment of antigen recognition.

  9. Two-dimensional nuclear magnetic resonance analysis of a labeled peptide bound to a class II major histocompatibility complex molecule.

    PubMed

    Driscoll, P C; Altman, J D; Boniface, J J; Sakaguchi, K; Reay, P A; Omichinski, J G; Appella, E; Davis, M M

    1993-07-20

    The formation of peptide/major histocompatibility complex (MHC) complexes and their subsequent recognition by T cells is a pivotal event in the initiation of an immune response. While X-ray crystal structures are now available for class I MHC/peptide complexes, little detailed structural information is known about the class II MHC equivalent, and there are no solution structure data for either. A 16 amino acid residue moth cytochrome c peptide (residues 88 to 103) was 13C-labeled for two-dimensional isotope-edited NMR analysis. The peptide was labeled either selectively in the methyl groups of alanine residues or uniformly at every carbon position, and bound to unlabeled soluble mouse I-Ek class II MHC molecules. Although alpha-helical in the native cytochrome c protein and with no uniform structure in solution, the peptide is bound to the I-Ek molecule with the alpha-carbon atoms of the 11 C-terminal residues held in the binding groove. This indicates that the class II MHC peptide binding site is somewhat larger than that of class I MHC molecules (> or = 11 amino acid residues versus 8 to 10 amino acid residues), consistent with recent data on eluted peptides. Despite the large size of the complex (approximately 70 kDa), nuclear Overhauser effects are clearly detectable between peptide side-chains and the MHC molecule. Indications of the buried or exposed nature of particular side-chains within the bound peptide are derived from the NMR data and these are used together with information from previous biological studies to propose a crude model of the interaction of the peptide with the groove of the MHC molecule. We find no evidence for a conformational change in the peptide/MHC complex in the spectra at pH 5.0 versus pH 7.0, despite a 40-fold faster on-rate for the peptide at the lower pH value. PMID:8393933

  10. Genetic variation of the major histocompatibility complex (MHC class II B gene) in the threatened Hume's pheasant, Syrmaticus humiae.

    PubMed

    Chen, Weicai; Bei, Yongjian; Li, Hanhua

    2015-01-01

    Major histocompatibility complex (MHC) genes are the most polymorphic genes in vertebrates and encode molecules that play a crucial role in pathogen resistance. As a result of their diversity, they have received much attention in the fields of evolutionary and conservation biology. Here, we described the genetic variation of MHC class II B (MHCIIB) exon 2 in a wild population of Hume's pheasant (Syrmaticus humiae), which has suffered a dramatic decline in population over the last three decades across its ranges in the face of heavy exploitation and habitat loss. Twenty-four distinct alleles were found in 73 S. humiae specimens. We found seven shared alleles among four geographical groups as well as six rare MHCIIB alleles. Most individuals displayed between one to five alleles, suggesting that there are at least three MHCIIB loci of the Hume's pheasant. The dN ⁄ dS ratio at putative antigen-binding sites (ABS) was significantly greater than one, indicating balancing selection is acting on MHCIIB exon 2. Additionally, recombination and gene conversion contributed to generating MHCIIB diversity in the Hume's pheasant. One to three recombination events and seventy-five significant gene conversion events were observed within the Hume's pheasant MHCIIB loci. The phylogenetic tree and network analysis revealed that the Hume's pheasant alleles do not cluster together, but are scattered through the tree or network indicating a trans-species evolutionary mode. These findings revealed the evolution of the Hume's pheasant MHC after suffering extreme habitat fragmentation.

  11. In situ detection of autoreactive CD4 T cells in brain and heart using major histocompatibility complex class II dextramers.

    PubMed

    Massilamany, Chandirasegaran; Gangaplara, Arunakumar; Jia, Ting; Elowsky, Christian; Li, Qingsheng; Zhou, You; Reddy, Jay

    2014-01-01

    This report demonstrates the use of major histocompatibility complex (MHC) class II dextramers for detection of autoreactive CD4 T cells in situ in myelin proteolipid protein (PLP) 139-151-induced experimental autoimmune encephalomyelitis (EAE) in SJL mice and cardiac myosin heavy chain-α (Myhc) 334-352-induced experimental autoimmune myocarditis (EAM) in A/J mice. Two sets of cocktails of dextramer reagents were used, where dextramers(+) cells were analyzed by laser scanning confocal microscope (LSCM): EAE, IA(s)/PLP 139-151 dextramers (specific)/anti-CD4 and IA(s)/Theiler's murine encephalomyelitis virus (TMEV) 70-86 dextramers (control)/anti-CD4; and EAM, IA(k)/Myhc 334-352 dextramers/anti-CD4 and IA(k)/bovine ribonuclease (RNase) 43-56 dextramers (control)/anti-CD4. LSCM analysis of brain sections obtained from EAE mice showed the presence of cells positive for CD4 and PLP 139-151 dextramers, but not TMEV 70-86 dextramers suggesting that the staining obtained with PLP 139-151 dextramers was specific. Likewise, heart sections prepared from EAM mice also revealed the presence of Myhc 334-352, but not RNase 43-56-dextramer(+) cells as expected. Further, a comprehensive method has also been devised to quantitatively analyze the frequencies of antigen-specific CD4 T cells in the 'Z' serial images. PMID:25145797

  12. Characterization of class II β chain major histocompatibility complex genes in a family of Hawaiian honeycreepers: 'amakihi (Hemignathus virens).

    PubMed

    Jarvi, Susan I; Bianchi, Kiara R; Farias, Margaret Em; Txakeeyang, Ann; McFarland, Thomas; Belcaid, Mahdi; Asano, Ashley

    2016-07-01

    Hawaiian honeycreepers (Drepanidinae) have evolved in the absence of mosquitoes for over five million years. Through human activity, mosquitoes were introduced to the Hawaiian archipelago less than 200 years ago. Mosquito-vectored diseases such as avian malaria caused by Plasmodium relictum and Avipoxviruses have greatly impacted these vulnerable species. Susceptibility to these diseases is variable among and within species. Due to their function in adaptive immunity, the role of major histocompatibility complex genes (Mhc) in disease susceptibility is under investigation. In this study, we evaluate gene organization and levels of diversity of Mhc class II β chain genes (exon 2) in a captive-reared family of Hawaii 'amakihi (Hemignathus virens). A total of 233 sequences (173 bp) were obtained by PCR+1 amplification and cloning, and 5720 sequences were generated by Roche 454 pyrosequencing. We report a total of 17 alleles originating from a minimum of 14 distinct loci. We detected three linkage groups that appear to represent three distinct haplotypes. Phylogenetic analysis revealed one variable cluster resembling classical Mhc sequences (DAB) and one highly conserved, low variability cluster resembling non-classical Mhc sequences (DBB). High net evolutionary divergence values between DAB and DBB resemble that seen between chicken BLB system and YLB system genes. High amino acid identity among non-classical alleles from 12 species of passerines (DBB) and four species of Galliformes (YLB) was found, suggesting that these non-classical passerine sequences may be related to the Galliforme YLB sequences. PMID:26971289

  13. Low major histocompatibility complex class II DQA diversity in the Giant Panda (Ailuropoda melanoleuca)

    PubMed Central

    Zhu, Liang; Ruan, Xiang-Dong; Ge, Yun-Fa; Wan, Qiu-Hong; Fang, Sheng-Guo

    2007-01-01

    Background The giant panda (Ailuropoda melanoleuca) is one of the most endangered animals due to habitat fragmentation and loss. Although the captive breeding program for this species is now nearly two decades old, researches on the genetic background of such captive populations, especially on adaptive molecular polymorphism of major histocompatibility complex (MHC), are still limited. In this study, we characterized adaptive variation of the giant panda's MHC DQA gene by PCR amplification of its antigen-recognizing region (i.e. the exon 2) and subsequent single-strand conformational polymorphism (SSCP) and sequence analyses. Results The results revealed a low level of DQA exon 2 diversity in this rare animal, presenting 6 alleles from 61 giant panda individuals. The observed polymorphism was restricted to 9 amino acid substitutions, all of which occurred at and adjacent to positions forming the functionally important antigen-binding sites. All the samples were in Hardy-Weinberg proportions. A significantly higher rate of non-synonymous than synonymous substitutions at the antigen-binding sites indicated positive selection for diversity in the locus. Conclusion The DQA allelic diversity of giant pandas was low relative to other vertebrates. Nonetheless, the pandas exhibited more alleles in DQA than those in DRB, suggesting the alpha chain genes would play a leading role when coping with certain pathogens and thus should be included in conservation genetic investigation. The microsatellite and MHC loci might predict long-term persistence potential and short-term survival ability, respectively. Consequently, it is recommended to utilize multiple suites of microsatellite markers and multiple MHC loci to detect overall genetic variation in order to design unbiased conservation strategies. PMID:17555583

  14. Relationship between gingival hyperplasia and class II histocompatibility antigens in renal transplant recipients.

    PubMed

    Türkmen, A; Ak, G; Furuncuoglu, Y; Akar, U; Seyhun, Y; Türk, S; Carin, M; Sever, M S

    2000-01-01

    Gingival hyperplasia, a well-known side effect of ciclosporin A (CS-A), is much more prominent when CS-A is used in combination with calcium channel blockers, especially dihydropyridines. On the other hand, it is interesting to note that this complication is not observed in all patients using this drug combination. This study was conducted in order to investigate the relationship (if any) between major histocompatibility complex antigens and gingival hyperplasia. Seventy-six renal transplantation patients were evaluated by an experienced dentist for gingival hyperplasia. The patients were then divided into two groups according to the presence (group 1, n = 18) or absence (group 2, n = 58) of gingival hyperplasia. There was no significant difference between the two groups regarding age, sex, transplant age, donor type, antihypertensive and immunosuppressive therapy protocols, and CS-A levels. HLA-DR2 antigen was present in 63% of the patients with gingival hyperplasia and in 34% of the patients without gingival hyperplasia. However, the HLA-DR1 antigen frequencies were found to be 11 and 22% in group 1 and group 2, respectively. In patients receiving nifedipine as an antihypertensive therapy, gingival hyperplasia developed more often than in patients receiving verapamil or diltiazem. As a result, in renal allograft recipients with HLA-DR1 antigen, gingival hyperplasia was seen less frequently than in HLA-DR2-positive patients. It is believed that the presence of these antigens regulates the response of the patients to either CS-A and/or calcium channel blockers.

  15. The great diversity of major histocompatibility complex class II genes in Philippine native cattle.

    PubMed

    Takeshima, S N; Miyasaka, T; Polat, M; Kikuya, M; Matsumoto, Y; Mingala, C N; Villanueva, M A; Salces, A J; Onuma, M; Aida, Y

    2014-12-01

    Bovine leukocyte antigens (BoLA) are extensively used as markers for bovine disease and immunological traits. However, none of the BoLA genes in Southeast Asian breeds have been characterized by polymerase chain reaction (PCR)-sequence-based typing (SBT). Therefore, we sequenced exon 2 of the BoLA class II DRB3 gene from 1120 individual cows belonging to the Holstein, Sahiwal, Simbrah, Jersey, Brahman, and Philippine native breeds using PCR-SBT. Several cross-breeds were also examined. BoLA-DRB3 PCR-SBT identified 78 previously reported alleles and five novel alleles. The number of BoLA-DRB3 alleles identified in each breed from the Philippines was higher (71 in Philippine native cattle, 58 in Brahman, 46 in Holstein × Sahiwal, and 57 in Philippine native × Brahman) than that identified in breeds from other countries (e.g., 23 alleles in Japanese Black and 35 in Bolivian Yacumeño cattle). A phylogenetic tree based on the DA distance calculated from the BoLA-DRB3 allele frequency showed that Philippine native cattle from different Philippine islands are closely related, and all of them are closely similar to Philippine Brahman cattle but not to native Japanese and Latin American breeds. Furthermore, the BoLA-DRB3 allele frequency in Philippine native cattle from Luzon Island, located in the Northern Philippines was different from that in cattle from Iloilo, Bohol, and Leyte Islands, which are located in the Southern Philippines. Therefore, we conclude that Philippine native cattle can be divided into two populations, North and South areas. Moreover, a neutrality test revealed that Philippine native cattle from Leyte showed significantly greater genetic diversity, which may be maintained by balancing selection. This study shows that Asian breeds have high levels of BoLA-DRB3 polymorphism. This finding, especially the identification of five novel BoLA-DRB3 alleles, will be helpful for future SBT studies of BoLA-DRB3 alleles in East Asian cattle. PMID:25606401

  16. The great diversity of major histocompatibility complex class II genes in Philippine native cattle.

    PubMed

    Takeshima, S N; Miyasaka, T; Polat, M; Kikuya, M; Matsumoto, Y; Mingala, C N; Villanueva, M A; Salces, A J; Onuma, M; Aida, Y

    2014-12-01

    Bovine leukocyte antigens (BoLA) are extensively used as markers for bovine disease and immunological traits. However, none of the BoLA genes in Southeast Asian breeds have been characterized by polymerase chain reaction (PCR)-sequence-based typing (SBT). Therefore, we sequenced exon 2 of the BoLA class II DRB3 gene from 1120 individual cows belonging to the Holstein, Sahiwal, Simbrah, Jersey, Brahman, and Philippine native breeds using PCR-SBT. Several cross-breeds were also examined. BoLA-DRB3 PCR-SBT identified 78 previously reported alleles and five novel alleles. The number of BoLA-DRB3 alleles identified in each breed from the Philippines was higher (71 in Philippine native cattle, 58 in Brahman, 46 in Holstein × Sahiwal, and 57 in Philippine native × Brahman) than that identified in breeds from other countries (e.g., 23 alleles in Japanese Black and 35 in Bolivian Yacumeño cattle). A phylogenetic tree based on the DA distance calculated from the BoLA-DRB3 allele frequency showed that Philippine native cattle from different Philippine islands are closely related, and all of them are closely similar to Philippine Brahman cattle but not to native Japanese and Latin American breeds. Furthermore, the BoLA-DRB3 allele frequency in Philippine native cattle from Luzon Island, located in the Northern Philippines was different from that in cattle from Iloilo, Bohol, and Leyte Islands, which are located in the Southern Philippines. Therefore, we conclude that Philippine native cattle can be divided into two populations, North and South areas. Moreover, a neutrality test revealed that Philippine native cattle from Leyte showed significantly greater genetic diversity, which may be maintained by balancing selection. This study shows that Asian breeds have high levels of BoLA-DRB3 polymorphism. This finding, especially the identification of five novel BoLA-DRB3 alleles, will be helpful for future SBT studies of BoLA-DRB3 alleles in East Asian cattle.

  17. The great diversity of major histocompatibility complex class II genes in Philippine native cattle

    PubMed Central

    Takeshima, S.N.; Miyasaka, T.; Polat, M.; Kikuya, M.; Matsumoto, Y.; Mingala, C.N.; Villanueva, M.A.; Salces, A.J.; Onuma, M.; Aida, Y.

    2014-01-01

    Bovine leukocyte antigens (BoLA) are extensively used as markers for bovine disease and immunological traits. However, none of the BoLA genes in Southeast Asian breeds have been characterized by polymerase chain reaction (PCR)-sequence-based typing (SBT). Therefore, we sequenced exon 2 of the BoLA class II DRB3 gene from 1120 individual cows belonging to the Holstein, Sahiwal, Simbrah, Jersey, Brahman, and Philippine native breeds using PCR-SBT. Several cross-breeds were also examined. BoLA-DRB3 PCR-SBT identified 78 previously reported alleles and five novel alleles. The number of BoLA-DRB3 alleles identified in each breed from the Philippines was higher (71 in Philippine native cattle, 58 in Brahman, 46 in Holstein × Sahiwal, and 57 in Philippine native × Brahman) than that identified in breeds from other countries (e.g., 23 alleles in Japanese Black and 35 in Bolivian Yacumeño cattle). A phylogenetic tree based on the DA distance calculated from the BoLA-DRB3 allele frequency showed that Philippine native cattle from different Philippine islands are closely related, and all of them are closely similar to Philippine Brahman cattle but not to native Japanese and Latin American breeds. Furthermore, the BoLA-DRB3 allele frequency in Philippine native cattle from Luzon Island, located in the Northern Philippines was different from that in cattle from Iloilo, Bohol, and Leyte Islands, which are located in the Southern Philippines. Therefore, we conclude that Philippine native cattle can be divided into two populations, North and South areas. Moreover, a neutrality test revealed that Philippine native cattle from Leyte showed significantly greater genetic diversity, which may be maintained by balancing selection. This study shows that Asian breeds have high levels of BoLA-DRB3 polymorphism. This finding, especially the identification of five novel BoLA-DRB3 alleles, will be helpful for future SBT studies of BoLA-DRB3 alleles in East Asian cattle. PMID:25606401

  18. Hepatitis B virus-like particles access major histocompatibility class I and II antigen presentation pathways in primary dendritic cells.

    PubMed

    Moffat, Jessica M; Cheong, Wan-Shoo; Villadangos, José A; Mintern, Justine D; Netter, Hans J

    2013-04-26

    Virus-like particles (VLPs) represent high density displays of viral proteins that efficiently trigger immunity. VLPs composed of the small hepatitis B virus envelope protein (HBsAgS) are useful vaccine platforms that induce humoral and cellular immune responses. Notably, however, some studies suggest HBsAgS VLPs impair dendritic cell (DC) function. Here we investigated HBsAgS VLP interaction with DC subsets and antigen access to major histocompatibility complex (MHC) class I and II antigen presentation pathways in primary DCs. HBsAgS VLPs impaired plasmacytoid DC (pDC) interferon alpha (IFNα) production in response to CpG in vitro, but did not alter conventional DC (cDC) or pDC phenotype when administered in vivo. To assess cellular immune responses, HBsAgS VLPs were generated containing the ovalbumin (OVA) model epitopes OVA(257-264) and OVA(323-339) to access MHCI and MHCII antigen presentation pathways, respectively; both in vitro and following immunisation in vivo. HBsAgS VLP-OVA(257-264) elicited CTL responses in vivo that were not enhanced by inclusion of an additional MHCII helper epitope. HBsAgS VLP-OVA(257-264) administered in vivo was cross-presented by CD8(+) DCs, but not CD8(-) DCs. Therefore, HBsAgS VLPs can deliver antigen to both MHCI and MHCII antigen presentation pathways in primary DCs and promote cytotoxic and helper T cell priming despite their suppressive effect on pDCs.

  19. Role of major histocompatibility complex class II in resistance of mice to naturally acquired infection with Syphacia obvelata

    NASA Technical Reports Server (NTRS)

    Stewart, Patricia W.; Chapes, Stephen K.

    2003-01-01

    Genetics plays a substantial role in host resistance in many host-parasite interactions. We examined the prevalence of naturally acquired infection with Syphacia obvelata in a number of mouse strains housed in a non-barrier facility. These mice, which included cross-bred and congenic, inbred strains on various genetic backgrounds, differ in the loci for the immune function genes--major histocompatibility complex class II (MHCII), toll-like receptor 4 (Tlr4), and solute carrier family 11, member 1 (Slc11a1)--which allowed comparisons of the impact of these genes on resistance to pinworm infection. Male and female mice of various ages were sampled over an 18-month period; infection was determined by use of the cellophane tape test. Results indicated that mice that were MHCII+/+ had a significantly lower prevalence of infection than did mice that were MHCII-/-. Differences were not seen between male and female mice. Although MHCII+/+ mice had an age-associated decrease in infection prevalence, such decrease was not seen in MHCII-/- mice. In contrast, infection prevalence in mice with the normal Tlr4 gene (Tlr4(LPS-n/LPS-n)) gene did not differ significantly compared with that in mice that were homozygous for either the point mutation (Tlr4(LPS-d/LPS-d)) or deletion (Tlr4(LPS-del/LPS-del)) of that gene. Likewise, the presence (Sle11a1r/r) or absence (Slc11a1s/s) of functional alleles for Slc11a1 had no effect on the prevalence of infection with S. obvelata. In conclusion, presence of MHCII, but not Tlr4 or Slc11a1 significantly influences prevalence of naturally acquired infection with S. obvelata. These data justify further comprehensive analyses of the immune components that are involved in pinworm resistance.

  20. Genetic diversity of the class II major histocompatibility DRA locus in European, Asiatic and African domestic donkeys.

    PubMed

    Vranova, Marie; Alloggio, Ingrid; Qablan, Moneeb; Vyskocil, Mirko; Baumeisterova, Aneta; Sloboda, Michal; Putnova, Lenka; Vrtkova, Irena; Modry, David; Horin, Petr

    2011-07-01

    The major histocompatibility complex (MHC) genes coding for antigen presenting molecules are the most polymorphic genes in vertebrate genome. The MHC class II DRA gene shows only small variation in many mammalian species, but it exhibits relatively high level of polymorphism in Equidae, especially in donkeys. This extraordinary degree of polymorphism together with signatures of selection in specific amino acids sites makes the donkey DRA gene a suitable model for population diversity studies. The objective of this study was to investigate the DRA gene diversity in three different populations of donkeys under infectious pressure of protozoan parasites, Theileria equi and Babesia caballi. Three populations of domestic donkeys from Italy (N = 68), Jordan (N = 43), and Kenya (N = 78) were studied. A method of the donkey MHC DRA genotyping based on PCR-RFLP and sequencing was designed. In addition to the DRA gene, 12 polymorphic microsatellite loci were genotyped. The presence of Theileria equi and Babesia caballi parasites in peripheral blood was investigated by PCR. Allele and genotype frequencies, observed and expected heterozygosities and F(IS) values were computed as parameters of genetic diversity for all loci genotyped. Genetic distances between the three populations were estimated based on F(ST) values. Statistical associations between parasite infection and genetic polymorphisms were sought. Extensive DRA locus variation characteristic for Equids was found. The results showed differences between populations both in terms of numbers of alleles and their frequencies as well as variation in expected heterozygosity values. Based on comparisons with neutral microsatellite loci, population sub-structure characteristics and association analysis, convincing evidence of pathogen-driven selection at the population level was not provided. It seems that genetic diversity observed in the three populations reflects mostly effects of selective breeding and their different

  1. A synthetic peptide from the third hypervariable region of major histocompatibility complex class II beta chain as a vaccine for treatment of experimental autoimmune encephalomyelitis.

    PubMed Central

    Topham, D J; Nag, B; Arimilli, S; Sriram, S

    1994-01-01

    Experimental autoimmune encephalomyelitis (EAE) is a class II major histocompatibility complex (MHC)-restricted, T-cell-mediated, demyelinating autoimmune disease of the central nervous system and represents a model for human multiple sclerosis. The present study demonstrates that vaccination of SJL/J mice with an 18-amino acid synthetic peptide from the third hypervariable region of the murine class II MHC IAs beta chain (IAs beta 58-75; 18-mer peptide) is capable of eliciting auto-anti-IAs antibodies specific for the IAs beta chain and preventing and treating EAE. A similar approach may be useful in the treatment of human autoimmune diseases in which susceptibility is linked to class II MHC genes. Images PMID:8058747

  2. Patterns of selection and allele diversity of class I and class II major histocompatibility loci across the species range of sockeye salmon (Oncorhynchus nerka).

    PubMed

    McClelland, Erin K; Ming, Tobi J; Tabata, Amy; Kaukinen, Karia H; Beacham, Terry D; Withler, Ruth E; Miller, Kristina M

    2013-09-01

    The major histocompatibility complex (MHC), an important component of the vertebrate immune system, provides an important suite of genes to examine the role of genetic diversity at non-neutral loci for population persistence. We contrasted patterns of diversity at the two classical MHC loci in sockeye salmon (Oncorhynchus nerka), MHC class I (UBA) and MHC class II (DAB), and neutral microsatellite loci across 70 populations spanning the species range from Washington State to Japan. There was no correlation in allelic richness or heterozygosity between MHC loci or between MHC loci and microsatellites. The two unlinked MHC loci may be responding to different selective pressures; the distribution of FST values for the two loci was uncorrelated, and evidence for both balancing and directional selection on alleles and lineages of DAB and UBA was observed in populations throughout the species range but rarely on both loci within a population. These results suggest that fluctuating selection has resulted in the divergence of MHC loci in contemporary populations. PMID:24033436

  3. Human class II major histocompatibility complex gene transfer into murine neuroblastoma leads to loss of tumorigenicity, immunity against subsequent tumor challenge, and elimination of microscopic preestablished tumors.

    PubMed

    Hock, R A; Reynolds, B D; Tucker-McClung, C L; Kwok, W W

    1995-01-01

    Immunological recognition of transformed cells is critically important to limit tumor development and proliferation. Because established tumors have escaped immune recognition and elimination, novel strategies to enhance antitumor immunity have been developed. A unique approach has used the introduction of genes encoding major histocompatibility complex (MHC) antigens into tumor cells. Experiments in mice have shown that the expression of syngeneic class II MHC antigens in tumor cells completely abrogates tumorigenicity and induces tumor-specific immunity. In this study we sought to determine whether a more effective antitumor immune response would be generated by introducing xenogeneic class II MHC genes into tumor cells. To address this question we used recombinant retroviruses to express human class II MHC genes in a highly malignant murine neuroblastoma cell line, Neuro-2a. We found that normal mice inoculated with Neuro-2a expressing the human class II MHC antigen did not develop tumors and were immune to subsequent challenge with unmodified Neuro-2a cells. In addition, mice bearing small established Neuro-2a tumors were cured by vaccination with Neuro-2a expressing human class II MHC. We hypothesize that a similar approach using retroviral-mediated transduction of class II MHC genes into human tumor cells may be an effective alternative to current cancer treatment.

  4. Disruption of hydrogen bonds between major histocompatibility complex class II and the peptide N-terminus is not sufficient to form a human leukocyte antigen-DM receptive state of major histocompatibility complex class II.

    PubMed

    Schulze, Monika-Sarah E D; Anders, Anne-Kathrin; Sethi, Dhruv K; Call, Melissa J

    2013-01-01

    Peptide presentation by MHC class II is of critical importance to the function of CD4+ T cells. HLA-DM resides in the endosomal pathway and edits the peptide repertoire of newly synthesized MHC class II molecules before they are exported to the cell surface. HLA-DM ensures MHC class II molecules bind high affinity peptides by targeting unstable MHC class II:peptide complexes for peptide exchange. Research over the past decade has implicated the peptide N-terminus in modulating the ability of HLA-DM to target a given MHC class II:peptide combination. In particular, attention has been focused on both the hydrogen bonds between MHC class II and peptide, and the occupancy of the P1 anchor pocket. We sought to solve the crystal structure of a HLA-DR1 molecule containing a truncated hemagglutinin peptide missing three N-terminal residues compared to the full-length sequence (residues 306-318) to determine the nature of the MHC class II:peptide species that binds HLA-DM. Here we present structural evidence that HLA-DR1 that is loaded with a peptide truncated to the P1 anchor residue such that it cannot make select hydrogen bonds with the peptide N-terminus, adopts the same conformation as molecules loaded with full-length peptide. HLA-DR1:peptide combinations that were unable to engage up to four key hydrogen bonds were also unable to bind HLA-DM, while those truncated to the P2 residue bound well. These results indicate that the conformational changes in MHC class II molecules that are recognized by HLA-DM occur after disengagement of the P1 anchor residue.

  5. Major histocompatibility complex class II dextramers: New tools for the detection of antigen-specific, CD4 T cells in basic and clinical research

    PubMed Central

    Massilamany, Chandirasegaran; Krishnan, Bharathi; Reddy, Jay

    2015-01-01

    The advent of major histocompatibility complex (MHC) tetramer technology has been a major contribution to T cell immunology, because tetramer reagents permit detection of antigen-specific T cells at the single-cell level in heterogeneous populations by flow cytometry. However, unlike MHC class I tetramers, the utility of MHC class II tetramers has been less frequently reported. MHC class II tetramers can be used successfully to enumerate the frequencies of antigen-specific CD4 T cells in cells activated in vitro, but their use for ex vivo analyses continues to be a problem, due in part to their activation dependency for binding with T cells. To circumvent this problem, we recently reported the creation of a new generation of reagents called MHC class II dextramers, which were found to be superior to their counterparts. In this review, we discuss the utility of class II dextramers vis-a-vis tetramers, with respect to their specificity and sensitivity, including potential applications and limitations. PMID:26207337

  6. The major histocompatibility complex class II-linked cim locus controls the kinetics of intracellular transport of a classical class I molecule

    PubMed Central

    1991-01-01

    The dominant trans-acting major histocompatibility complex (MHC)-linked class I modifier (cim) locus, previously recognized through its ability to determine altered alloantigenicity of a rat class I molecule, RT1.A3, is shown here to influence class I intracellular transport. The MHC recombinant laboratory rat strains PVG.R1 and PVG.R8 display unusually long retention of RT1.Aa within the endoplasmic reticulum or cis-Golgi. In appropriate F1 hybrid cells heterozygous for RT1.Aa and another class I MHC allele, RT1.Ac, only the RT1.Aa protein is subject to slow transport. The cim gene product therefore shows class I allele specificity in its action, cim appears to be a polymorphic locus whose product is directly involved in the processes of class I MHC assembly and/or intracellular transport. PMID:2007857

  7. Evolution of the major histocompatibility complex: Isolation of class II beta cDNAs from two monotremes, the platypus and the short-beaked echidna.

    PubMed

    Belov, Katherine; Lam, Mary K P; Hellman, Lars; Colgan, Donald J

    2003-09-01

    Extant mammals are composed of three lineages: the eutherians, the marsupials and the monotremes. The majority of the mammalian major histocompatibility complex (MHC) data is based on the eutherian mammals, which generally have three classical MHC class II beta chain gene clusters - DRB, DQB and DPB, as well as the non-classical DMB and DOB. Marsupial DMB, DAB and DBB have been characterised. Confusion still surrounds the relationship of the marsupial DAB and DBB genes with the classical eutherian class II clusters. Here we present the first monotreme MHC class II beta chain sequences. Four MHC class II beta chain sequences were isolated from a spleen cDNA library from the short-beaked echidna, and one from a spleen cDNA library from platypus using a brushtail possum DAB probe. Given the non-orthologous relationship of the monotreme sequences with marsupial and eutherian beta chain clusters, we recommend that the five new monotreme sequences be assigned the nomenclature 'DZB', signifying the description of a new mammalian beta chain cluster. Our analysis suggests that all mammalian beta chain sequences (except DMB) evolved from a common ancestor. Maximum likelihood analysis places the monotreme beta chain sequences at the base of the mammalian clade, indicating their ancestral status. However, within the mammalian clade, monophyletic clades are not robust, and elucidation of the order of gene duplication that gave rise to the present-day gene clusters is not yet possible.

  8. Major Histocompatibility Complex Class II Expression and Hemagglutinin Subtype Influence the Infectivity of Type A Influenza Virus for Respiratory Dendritic Cells ▿

    PubMed Central

    Hargadon, Kristian M.; Zhou, Haixia; Albrecht, Randy A.; Dodd, Haley A.; García-Sastre, Adolfo; Braciale, Thomas J.

    2011-01-01

    Dendritic cells (DC) play a key role in antiviral immunity, functioning both as innate effector cells in early phases of the immune response and subsequently as antigen-presenting cells that activate the adaptive immune response. In the murine respiratory tract, there are several respiratory dendritic cell (RDC) subsets, including CD103+ DC, CD11bhi DC, monocyte/macrophage DC, and plasmacytoid DC. However, little is known about the interaction between these tissue-resident RDC and viruses that are encountered during natural infection in the respiratory tract. Here, we show both in vitro and in vivo that the susceptibility of murine RDC to infection with type A influenza virus varies with the level of MHC class II expression by RDC and with the virus strain. Both CD103+ and CD11bhi RDC, which express the highest basal level of major histocompatibility complex (MHC) class II, are highly susceptible to infection by type A influenza virus. However, efficient infection is restricted to type A influenza virus strains of the H2N2 subtype. Furthermore, enhanced infectivity by viruses of the H2N2 subtype is linked to expression of the I-E MHC class II locus product. These results suggest a potential novel role for MHC class II molecules in influenza virus infection and pathogenesis in the respiratory tract. PMID:21917972

  9. A step-by-step overview of the dynamic process of epitope selection by major histocompatibility complex class II for presentation to helper T cells

    PubMed Central

    Sadegh-Nasseri, Scheherazade

    2016-01-01

    T cell antigen receptors (TCRs) expressed on cytotoxic or helper T cells can only see their specific target antigen as short sequences of peptides bound to the groove of proteins of major histocompatibility complex (MHC) class I, and class II respectively. In addition to the many steps, several participating proteins, and multiple cellular compartments involved in the processing of antigens, the MHC structure, with its dynamic and flexible groove, has perfectly evolved as the underlying instrument for epitope selection. In this review, I have taken a step-by-step, and rather historical, view to describe antigen processing and determinant selection, as we understand it today, all based on decades of intense research by hundreds of laboratories. PMID:27347387

  10. CD4 binding to major histocompatibility complex class II antigens induces LFA-1-dependent and -independent homotypic adhesion of B lymphocytes.

    PubMed

    Kansas, G S; Cambier, J C; Tedder, T F

    1992-01-01

    T helper cells recognize processed antigen (Ag) in the context of major histocompatibility complex (MHC) class II antigens present on the surface of B cells and other Ag-presenting cells. This interaction is mediated through the T cell receptor complex with associate recognition of class II molecules by the CD4 molecule. In this study, the binding of a soluble recombinant CD4/Ig heavy chain fusion protein (CD4-gamma 3) or monoclonal antibody (mAb) to class II antigens on human B cells was shown to induce rapid and specific homotypic adhesion of B cells and most B lymphoblastoid cell lines. mAb reactive with CD4 inhibited CD4-gamma 3-induced adhesion and a mutant B lymphoblastoid cell line deficient in class II antigens failed to respond. Induction of homotypic adhesion was dependent on energy metabolism and a functional cytoskeleton, and class II+ pre-B cells did not exhibit adhesion in response to these stimuli, suggesting that cross-linking of class II molecules generated a transmembrane signal and did not simply aggregate cells. In addition, MHC class II-induced adhesion was Fc receptor independent, as 15 mAb of different Ig isotypes reactive with HLA-D or HLA-DQ gene products induced adhesion. Anti-class II mAb and CD4-gamma 3 were able to induce adhesion at concentrations as low as 10 ng/ml and 100 ng/ml, respectively. Suboptimal stimulation of B cell lines through HLA-D antigens induced homotypic adhesion that was dependent on the activation of LFA-1 (CD11a/CD18), and which could be blocked by specific mAb. However, at greater signal strengths, adhesion was not blocked by mAb against the known adhesion receptors, suggesting the induction of a novel adhesion pathway. Consistent with this, homotypic adhesion induced by engagement of MHC class II antigens was observed with LFA-1-deficient B cell lines, and was independent of CD49d or CD18 expression. Thus, the direct engagement of B cell class II antigens by CD4 is likely to generate transmembrane signals which

  11. Antigen processing by epidermal Langerhans cells correlates with the level of biosynthesis of major histocompatibility complex class II molecules and expression of invariant chain

    PubMed Central

    1990-01-01

    Two prior studies with a small number of T cell lines have shown that the presentation of native protein antigens by epidermal Langerhans cells (LC) is regulated. When freshly isolated, LC are efficient antigen-presenting cells (APC), but after a period of culture LC are inefficient or even inactive. The deficit in culture seems to be a selective loss in antigen processing, since cultured LC are otherwise rich in major histocompatibility complex (MHC) class II products and are active APC for alloantigens and mitogens, which do not require processing. We have extended the analysis by studying presentation to bulk populations of primed lymph node and a T-T hybrid. Only freshly isolated LC can be pulsed with the protein antigens myoglobin and conalbumin, but once pulsed, antigen is retained in an immunogenic form for at least 2 d. The acquisition of antigen, presumably as MHC-peptide complexes, is inhibited if the fresh LC are exposed to foreign protein in the presence of chloroquine or cycloheximide. The latter, in contrast, improves the efficacy of antigen pulsing in anti-Ig- stimulated B blasts. In additional studies of mechanism, we noted that both fresh and cultured LC endocytose similar amounts of an antigen, rhodamineovalbumin, into perinuclear granules. However, freshly isolated LC synthesize high levels class II MHC molecules and express higher amounts of the class II-associated invariant chain. Fresh LC are at least 5-10 times more active than many other cells types in the level of biosynthesis of MHC class II products. These findings provide a physiologic model in which newly synthesized MHC class II molecules appear to be the principal vehicle for effective antigen processing by APC of the dendritic cell lineage. Another APC, the B lymphoblast, does not appear to require newly synthesized MHC class II molecules for presentation. PMID:2121888

  12. Increased susceptibility to Strongyloides venezuelensis infection is related to the parasite load and absence of major histocompatibility complex (MHC) class II molecules.

    PubMed

    Rodrigues, Rosângela Maria; Cardoso, Cristina Ribeiro; Gonçalves, Ana Lúcia Ribeiro; Silva, Neide Maria; Massa, Virgínia; Alves, Ronaldo; Ueta, Marlene Tiduko; Silva, João Santana; Costa-Cruz, Julia Maria

    2013-11-01

    In human and murine models strongyloidiasis induce a Th2 type response. In the current study we investigated the role of different loads of Strongyloides venezuelensis in the immune response raised against the parasite and the participation of the major histocompatibility complex (MHC) class II molecule in the disease outcome in face of the different parasite burden. The C57BL/6 wild type (WT) and MHC II(-/-) mice were individually inoculated by subcutaneous injection with 500 or 3000 S. venezuelensis L3. The MHC II(-/-) mice infected with 3000L3 were more susceptible to S. venezuelensis infection when compared with WT groups, in which the parasite was completely eliminated. The production of Th2 cytokines and specific IgG1 or IgE antibodies against parasite were significantly lowered in MHC II(-/-) infected mice with different larvae inoculums. The infection of MHC II(-/-) mice with S. venezuelensis induced slight inflammatory alterations in the small intestine, and these lesions were lower when compared with WT mice, irrespective of the parasite load utilized to infect animals. Finally, we concluded that MHC class II molecules are essential in the immune response against S. venezuelensis mainly when infection occurs with high parasite inoculum.

  13. Sequence polymorphism of two major histocompatibility (MH) class II B genes and their association with Vibrio anguillarum infection in half-smooth tongue sole ( Cynoglossus semilaevis)

    NASA Astrophysics Data System (ADS)

    Li, Chunmei; Zhang, Quanqi; Yu, Yan; Li, Shuo; Zhong, Qiwang; Sun, Yeying; Wang, Zhigang; Qi, Jie; Zhai, Jieming; Wang, Xubo

    2011-11-01

    Major histocompatibility complex (MHC) class II B molecules play an important role in the adaptive immune response in fish. Previous study has reported that two highly polymorphic class II B genes, Cyse-DAB and Cyse-DBB exist in half-smooth tongue sole ( Cynoglossus semilaevis). In this study, the polymorphism within exon 2 of the class II B genes following bacterial challenge was evaluated. Two hundred C. semilaevis individuals were injected intraperitoneally with Vibrio anguillarum. Muscle tissue from the first 20 dead and 20 of the survivors was collected for genotyping. Sixty alleles from the 40 individuals were isolated, of which 32 belonged to Cyse-DAB and 28 belonged to Cyse-DBB. The rate of d N (non-synonymous substitution) was higher than that of d S (synonymous substitution) in the PBRs (peptide binding residues) of both class II B genes. Conversely, the rate of d S was higher than d N in the non-PBRs and the complete exon 2 sequence. Thus, the results suggest that positive selection has occurred in the PBRs and purifying selection in the non-PBRs and exon 2. Thirteen class II B alleles were used to study the association between alleles and resistance to infection. Though not significant, alleles Cyse-DAB*0601, Cyse-DAB*0706, and Cyse-DBB*0101, Cyse-DBB*1301 were only found in surviving individuals and may represent alleles that have resistance against V. anguillarum infection. Alleles Cyse-DAB*0701 and Cyse-DAB*1301 were significantly more prevalent in dead individuals than in surviving ones and may represent alleles that are associated with increased susceptibility to V. anguillarum infection.

  14. Histone deacetylase 1/mSin3A disrupts gamma interferon-induced CIITA function and major histocompatibility complex class II enhanceosome formation.

    PubMed

    Zika, Eleni; Greer, Susanna F; Zhu, Xin-Sheng; Ting, Jenny P-Y

    2003-05-01

    The class II transactivator (CIITA) is a master transcriptional regulator of major histocompatibility complex class II (MHC-II) promoters. CIITA does not bind DNA, but it interacts with the transcription factors RFX5, NF-Y, and CREB and associated chromatin-modifying enzymes to form an enhanceosome. This report examines the effects of histone deacetylases 1 and 2 (HDAC1/HDAC2) on MHC-II gene induction by gamma interferon (IFN-gamma) and CIITA. The results show that an inhibitor of HDACs, trichostatin A, enhances IFN-gamma-induced MHC-II expression, while HDAC1/HDAC2 inhibits IFN-gamma- and CIITA-induced MHC-II gene expression. mSin3A, a corepressor of HDAC1/HDAC2, is important for this inhibition, while NcoR, a corepressor of HDAC3, is not. The effect of this inhibition is directed at CIITA, since HDAC1/HDAC2 reduces transactivation by a GAL4-CIITA fusion protein. CIITA binds to overexpressed and endogenous HDAC1, suggesting that HDAC and CIITA may affect each other by direct or indirect association. Inhibition of HDAC activity dramatically increases the association of NF-YB and RFX5 with CIITA, the assembly of CIITA, NF-YB, and RFX5 enhanceosome, and the extent of H3 acetylation at the MHC-II promoter. These results suggest a model where HDAC1/HDAC2 affect the function of CIITA through a disruption of MHC-II enhanceosome and relevant coactivator-transcription factor association and provide evidence that CIITA may act as a molecular switch to modulate MHC-II transcription by coordinating the functions of both histone acetylases and HDACs.

  15. Class II major histocompatibility complex molecules regulate the development of the T4+T8- inducer phenotype of cultured human thymocytes.

    PubMed Central

    Blue, M L; Daley, J F; Levine, H; Schlossman, S F

    1985-01-01

    We demonstrate that a variety of Ia+ cells has the ability to promote the development of human T4+T8- thymocytes in vitro. Prolonged thymocyte culture in the absence of Ia+ accessory cells results in a predominantly T8+T4- cell population. The generation of T4+ cells in the presence of irradiated Ia+ cells could be suppressed up to 70% by a monoclonal antibody directed against a nonpolymorphic epitope on HLA-DR. Using two-color fluorescence sorting techniques, we were able to identify the activated T4+T8+ thymocyte as the cell that interacts with Ia and gives rise to the T4+T8- cell subset. These results directly and specifically implicate class II major histocompatibility complex molecules in the differentiative pathway of the human thymocyte. Images PMID:2933749

  16. Parasite Manipulation of the Invariant Chain and the Peptide Editor H2-DM Affects Major Histocompatibility Complex Class II Antigen Presentation during Toxoplasma gondii Infection.

    PubMed

    Leroux, Louis-Philippe; Nishi, Manami; El-Hage, Sandy; Fox, Barbara A; Bzik, David J; Dzierszinski, Florence S

    2015-10-01

    Toxoplasma gondii is an obligate intracellular protozoan parasite. This apicomplexan is the causative agent of toxoplasmosis, a leading cause of central nervous system disease in AIDS. It has long been known that T. gondii interferes with major histocompatibility complex class II (MHC-II) antigen presentation to attenuate CD4(+) T cell responses and establish persisting infections. Transcriptional downregulation of MHC-II genes by T. gondii was previously established, but the precise mechanisms inhibiting MHC-II function are currently unknown. Here, we show that, in addition to transcriptional regulation of MHC-II, the parasite modulates the expression of key components of the MHC-II antigen presentation pathway, namely, the MHC-II-associated invariant chain (Ii or CD74) and the peptide editor H2-DM, in professional antigen-presenting cells (pAPCs). Genetic deletion of CD74 restored the ability of infected dendritic cells to present a parasite antigen in the context of MHC-II in vitro. CD74 mRNA and protein levels were, surprisingly, elevated in infected cells, whereas MHC-II and H2-DM expression was inhibited. CD74 accumulated mainly in the endoplasmic reticulum (ER), and this phenotype required live parasites, but not active replication. Finally, we compared the impacts of genetic deletion of CD74 and H2-DM genes on parasite dissemination toward lymphoid organs in mice, as well as activation of CD4(+) T cells and interferon gamma (IFN-γ) levels during acute infection. Cyst burdens and survival during the chronic phase of infection were also evaluated in wild-type and knockout mice. These results highlight the fact that the infection is influenced by multiple levels of parasite manipulation of the MHC-II antigen presentation pathway. PMID:26195549

  17. Identification of two major histocompatibility (MH) class II A genes and their association to Vibrio anguillarum infection in half-smooth tongue sole ( Cynoglossus semilaevis)

    NASA Astrophysics Data System (ADS)

    Li, Chunmei; Wang, Xubo; Zhang, Quanqi; Wang, Zhigang; Qi, Jie; Yi, Qilin; Liu, Zhipeng; Wang, Yanan; Yu, Haiyang

    2012-03-01

    Major histocompatibility complex class II antigens are important in vertebrate immune system. In the present study, the full cDNA sequence of class II A gene was synthesized by RACE-PCR from half-smooth tongue sole ( Cynoglossus semilaevis), and its open reading frame (ORF) polymorphism was studied. The whole cDNA sequence was 992 bp in length, including the ORF with 717 bp. Twenty-five alleles were identified and clustered into two distinct groups according to the specific nucleotides/ amino acids in specific positions. Eleven alleles belonged to Cyse-DAA while fourteen alleles belonged to Cyse-DBA. Four Cyse-DAA alleles were observed in one individual, and three to five Cyse-DBA alleles were observed in each of the three detected individuals, which indicated that at least two loci existed in each gene. Moreover, in order to study the function of the alleles in resistance to infection, 200 individuals were intraperitoneally injected with Vibrio anguillarum and the first 20 dead individuals and 20 surviving ones were selected for genotype analysis. Fifty-six alleles were identified among the 40 individuals. Twenty-nine alleles belonged to Cyse-DAA and the other 27 alleles belonged to Cyse-DBA. Eighteen alleles were selected for studying their function in resistance to infection. Alleles Cyse-DAA*0201, Cyse-DAA*1101, Cyse-DBA*0401, Cyse-DBA*1102, Cyse-DBA*1801 and Cyse-DBA*2201 were identified only in surviving individuals, while alleles Cyse- DAA*0901, Cyse-DBA*1101 and Cyse-DBA*1401 occurred more frequently in dead individuals. This study confirmed the existence and polymorphism of two class II A genes as well as the relationship between alleles of class II A genes and disease susceptibility/ resistance in half-smooth tongue sole.

  18. Murine aortic smooth muscle cells acquire, though fail to present exogenous protein antigens on major histocompatibility complex class II molecules.

    PubMed

    Maddaluno, Marcella; MacRitchie, Neil; Grassia, Gianluca; Ialenti, Armando; Butcher, John P; Garside, Paul; Brewer, James M; Maffia, Pasquale

    2014-01-01

    In the present study aortic murine smooth muscle cell (SMC) antigen presentation capacity was evaluated using the Eα-GFP/Y-Ae system to visualize antigen uptake through a GFP tag and tracking of Eα peptide/MHCII presentation using the Y-Ae Ab. Stimulation with IFN-γ (100 ng/mL) for 72 h caused a significant (P < 0.01) increase in the percentage of MHC class II positive SMCs, compared with unstimulated cells. Treatment with Eα-GFP (100 μg/mL) for 48 h induced a significant (P < 0.05) increase in the percentage of GFP positive SMCs while it did not affect the percentage of Y-Ae positive cells, being indicative of antigen uptake without its presentation in the context of MHC class II. After IFN-γ-stimulation, ovalbumin- (OVA, 1 mg/mL) or OVA323-339 peptide-(0.5 μg/mL) treated SMCs failed to induce OT-II CD4(+) T cell activation/proliferation; this was also accompanied by a lack of expression of key costimulatory molecules (OX40L, CD40, CD70, and CD86) on SMCs. Finally, OVA-treated SMCs failed to induce DO11.10-GFP hybridoma activation, a process independent of costimulation. Our results demonstrate that while murine primary aortic SMCs express MHC class II and can acquire exogenous antigens, they fail to activate T cells through a failure in antigen presentation and a lack of costimulatory molecule expression.

  19. Brucella abortus Inhibits Major Histocompatibility Complex Class II Expression and Antigen Processing through Interleukin-6 Secretion via Toll-Like Receptor 2▿

    PubMed Central

    Barrionuevo, Paula; Cassataro, Juliana; Delpino, M. Victoria; Zwerdling, Astrid; Pasquevich, Karina A.; Samartino, Clara García; Wallach, Jorge C.; Fossati, Carlos A.; Giambartolomei, Guillermo H.

    2008-01-01

    The strategies that allow Brucella abortus to survive inside macrophages for prolonged periods and to avoid the immunological surveillance of major histocompatibility complex class II (MHC-II)-restricted gamma interferon (IFN-γ)-producing CD4+ T lymphocytes are poorly understood. We report here that infection of THP-1 cells with B. abortus inhibited expression of MHC-II molecules and antigen (Ag) processing. Heat-killed B. abortus (HKBA) also induced both these phenomena, indicating the independence of bacterial viability and involvement of a structural component of the bacterium. Accordingly, outer membrane protein 19 (Omp19), a prototypical B. abortus lipoprotein, inhibited both MHC-II expression and Ag processing to the same extent as HKBA. Moreover, a synthetic lipohexapeptide that mimics the structure of the protein lipid moiety also inhibited MHC-II expression, indicating that any Brucella lipoprotein could down-modulate MHC-II expression and Ag processing. Inhibition of MHC-II expression and Ag processing by either HKBA or lipidated Omp19 (L-Omp19) depended on Toll-like receptor 2 and was mediated by interleukin-6. HKBA or L-Omp19 also inhibited MHC-II expression and Ag processing of human monocytes. In addition, exposure to the synthetic lipohexapeptide inhibited Ag-specific T-cell proliferation and IFN-γ production of peripheral blood mononuclear cells from Brucella-infected patients. Together, these results indicate that there is a mechanism by which B. abortus may prevent recognition by T cells to evade host immunity and establish a chronic infection. PMID:17984211

  20. Evidence for a conformational change in a class II major histocompatibility complex molecule occurring in the same pH range where antigen binding is enhanced

    PubMed Central

    1996-01-01

    Many class II histocompatibility complex molecules bind antigenic peptides optimally at low pH, consistent with their exposure to antigen in acidic endosomal compartments. While it has been suggested that a partially unfolded state serves as an intermediate involved in peptide binding, very little evidence for such a state has been obtained. In this report, we show that the murine class II molecule IE becomes increasingly less stable to sodium dodecyl sulfate-induced dissociation since the pH is decreased in the same range that enhances antigenic peptide binding. Furthermore, at mildly acidic pH levels, IEk binds the fluorescent dye 1-anilino-naphthalene-8-sulfonic acid (ANS), a probe for exposed nonpolar sites in proteins, suggesting that protonation produces a molten globule-like state. The association of IEk with a single high-affinity peptide had only a small effect in these two assays, indicating that the changes that occur are distal to the peptide-binding groove. Circular dichroism analysis shows that a pH shift from neutral to mildly acidic pH causes subtle changes in the environment of aromatic residues but does not grossly disrupt the secondary structure of IEk. We propose a model in which perturbations in interdomain contacts outside the peptide-binding domain of IEk occur at acidic pH, producing a partially unfolded state that facilitates optimal antigen binding. PMID:8551214

  1. Domain structures and molecular evolution of class I and class II major histocompatibility gene complex (MHC) products deduced from amino acid and nucleotide sequence homologies

    NASA Astrophysics Data System (ADS)

    Ohnishi, Koji

    1984-12-01

    Domain structures of class I and class II MHC products were analyzed from a viewpoint of amino acid and nucleotide sequence homologies. Alignment statistics revealed that class I (transplantation) antigen H chains consist of four mutually homologous domains, and that class II (HLA-DR) antigen β and α chains are both composed of three mutually homologous ones. The N-terminal three and two domains of class I and class II (both β and α) gene products, respectively, all of which being ˜90 residues long, were concluded to be homologous to β2-microglobulin (β2M). The membraneembedded C-terminal shorter domains of these MHC products were also found to be homologous to one another and to the third domain of class I H chains. Class I H chains were found to be more closely related to class II α chains than to class II β chains. Based on these findings, an exon duplication history from a common ancestral gene encoding a β2M-like primodial protein of one-domain-length up to the contemporary MHC products was proposed.

  2. Class II major histocompatibility complex mutant mice to study the germ-line bias of T-cell antigen receptors.

    PubMed

    Silberman, Daniel; Krovi, Sai Harsha; Tuttle, Kathryn D; Crooks, James; Reisdorph, Richard; White, Janice; Gross, James; Matsuda, Jennifer L; Gapin, Laurent; Marrack, Philippa; Kappler, John W

    2016-09-20

    The interaction of αβ T-cell antigen receptors (TCRs) with peptides bound to MHC molecules lies at the center of adaptive immunity. Whether TCRs have evolved to react with MHC or, instead, processes in the thymus involving coreceptors and other molecules select MHC-specific TCRs de novo from a random repertoire is a longstanding immunological question. Here, using nuclease-targeted mutagenesis, we address this question in vivo by generating three independent lines of knockin mice with single-amino acid mutations of conserved class II MHC amino acids that often are involved in interactions with the germ-line-encoded portions of TCRs. Although the TCR repertoire generated in these mutants is similar in size and diversity to that in WT mice, the evolutionary bias of TCRs for MHC is suggested by a shift and preferential use of some TCR subfamilies over others in mice expressing the mutant class II MHCs. Furthermore, T cells educated on these mutant MHC molecules are alloreactive to each other and to WT cells, and vice versa, suggesting strong functional differences among these repertoires. Taken together, these results highlight both the flexibility of thymic selection and the evolutionary bias of TCRs for MHC. PMID:27588903

  3. Class II major histocompatibility complex mutant mice to study the germ-line bias of T-cell antigen receptors

    PubMed Central

    Silberman, Daniel; Krovi, Sai Harsha; Tuttle, Kathryn D.; Crooks, James; Reisdorph, Richard; White, Janice; Gross, James; Matsuda, Jennifer L.; Gapin, Laurent; Marrack, Philippa; Kappler, John W.

    2016-01-01

    The interaction of αβ T-cell antigen receptors (TCRs) with peptides bound to MHC molecules lies at the center of adaptive immunity. Whether TCRs have evolved to react with MHC or, instead, processes in the thymus involving coreceptors and other molecules select MHC-specific TCRs de novo from a random repertoire is a longstanding immunological question. Here, using nuclease-targeted mutagenesis, we address this question in vivo by generating three independent lines of knockin mice with single-amino acid mutations of conserved class II MHC amino acids that often are involved in interactions with the germ-line–encoded portions of TCRs. Although the TCR repertoire generated in these mutants is similar in size and diversity to that in WT mice, the evolutionary bias of TCRs for MHC is suggested by a shift and preferential use of some TCR subfamilies over others in mice expressing the mutant class II MHCs. Furthermore, T cells educated on these mutant MHC molecules are alloreactive to each other and to WT cells, and vice versa, suggesting strong functional differences among these repertoires. Taken together, these results highlight both the flexibility of thymic selection and the evolutionary bias of TCRs for MHC. PMID:27588903

  4. Class II major histocompatibility complex mutant mice to study the germ-line bias of T-cell antigen receptors.

    PubMed

    Silberman, Daniel; Krovi, Sai Harsha; Tuttle, Kathryn D; Crooks, James; Reisdorph, Richard; White, Janice; Gross, James; Matsuda, Jennifer L; Gapin, Laurent; Marrack, Philippa; Kappler, John W

    2016-09-20

    The interaction of αβ T-cell antigen receptors (TCRs) with peptides bound to MHC molecules lies at the center of adaptive immunity. Whether TCRs have evolved to react with MHC or, instead, processes in the thymus involving coreceptors and other molecules select MHC-specific TCRs de novo from a random repertoire is a longstanding immunological question. Here, using nuclease-targeted mutagenesis, we address this question in vivo by generating three independent lines of knockin mice with single-amino acid mutations of conserved class II MHC amino acids that often are involved in interactions with the germ-line-encoded portions of TCRs. Although the TCR repertoire generated in these mutants is similar in size and diversity to that in WT mice, the evolutionary bias of TCRs for MHC is suggested by a shift and preferential use of some TCR subfamilies over others in mice expressing the mutant class II MHCs. Furthermore, T cells educated on these mutant MHC molecules are alloreactive to each other and to WT cells, and vice versa, suggesting strong functional differences among these repertoires. Taken together, these results highlight both the flexibility of thymic selection and the evolutionary bias of TCRs for MHC.

  5. Association between Single Nucleotide Polymorphisms of the Major Histocompatibility Complex Class II Gene and Newcastle Disease Virus Titre and Body Weight in Leung Hang Khao Chickens

    PubMed Central

    Molee, A.; Kongroi, K.; Kuadsantia, P.; Poompramun, C.; Likitdecharote, B.

    2016-01-01

    The aim of the present study was to investigate the effect of single nucleotide polymorphisms in the major histocompatibility complex (MHC) class II gene on resistance to Newcastle disease virus and body weight of the Thai indigenous chicken, Leung Hang Khao (Gallus gallus domesticus). Blood samples were collected for single nucleotide polymorphism analysis from 485 chickens. Polymerase chain reaction sequencing was used to classify single nucleotide polymorphisms of class II MHC. Body weights were measured at the ages of 3, 4, 5, and 7 months. Titres of Newcastle disease virus at 2 weeks to 7 months were determined and the correlation between body weight and titre was analysed. The association between single nucleotide polymorphisms and body weight and titre were analysed by a generalized linear model. Seven single nucleotide polymorphisms were identified: C125T, A126T, C209G, C242T, A243T, C244T, and A254T. Significant correlations between log titre and body weight were found at 2 and 4 weeks. Associations between single nucleotide polymorphisms and titre were found for C209G and A254T, and between all single nucleotide polymorphisms (except A243T) and body weight. The results showed that class II MHC is associated with both titre of Newcastle disease virus and body weight in Leung Hang Khao chickens. This is of concern because improved growth traits are the main goal of breeding selection. Moreover, the results suggested that MHC has a pleiotropic effect on the titre and growth performance. This mechanism should be investigated in a future study. PMID:26732325

  6. A molecular map of the chicken major histocompatibility complex: the class II beta genes are closely linked to the class I genes and the nucleolar organizer.

    PubMed Central

    Guillemot, F; Billault, A; Pourquié, O; Béhar, G; Chaussé, A M; Zoorob, R; Kreibich, G; Auffray, C

    1988-01-01

    We have cloned in a cosmid vector four DNA clusters covering 320 kb of the chicken MHC (B complex), including five class II (B-L) beta genes defining two related isotypic families. Additional B complex genes have been revealed using tissue-specific cDNA probes. A cosmid fragment has been used to isolate a cDNA for a class I (B-F) transcript. This transcript, that is by far the most divergent known member of the class I gene family, hybridized to six B-F genes present in the cosmids. One of the clusters was shown to contain two rRNA transcriptional units from the nucleolar organizer region (NOR), marking the telomeric boundary of the B complex. None of the other B complex genes hybridizes to, or has the transcriptional characteristics of mammalian MHC class II alpha or class III genes. The map we have obtained shows that the B complex does not contain well defined class I and class II regions since B-F and B-L beta genes are closely associated with unrelated genes. Moreover, class II beta genes are very closely linked to class I genes in two clusters, and to the NOR in a third one. Images PMID:3141149

  7. Key Role of Toll-Like Receptor 2 in the Inflammatory Response and Major Histocompatibility Complex Class II Downregulation in Brucella abortus-Infected Alveolar Macrophages

    PubMed Central

    Ferrero, Mariana C.; Hielpos, M. Soledad; Carvalho, Natalia B.; Barrionuevo, Paula; Corsetti, Patricia P.; Giambartolomei, Guillermo H.; Oliveira, Sergio C.

    2014-01-01

    Alveolar macrophages (AM) seem to constitute the main cellular target of inhaled brucellae. Here, we show that Brucella abortus invades and replicates in murine AM without inducing cytotoxicity. B. abortus infection induced a statistically significant increase of tumor necrosis factor alpha (TNF-α), CXCL1 or keratinocyte chemoattractant (KC), interleukin-1β (IL-1β), IL-6, and IL-12 in AM from C57BL/6 mice and BALB/c mice, but these responses were generally weaker and/or delayed compared to those elicited in peritoneal macrophages. Studies using knockout mice for TLR2, TLR4, and TLR9 revealed that TNF-α and KC responses were mediated by TLR2 recognition. Brucella infection reduced in a multiplicity of infection-dependent manner the expression of major histocompatibility complex class II (MHC-II) molecules induced by gamma interferon (IFN-γ) in AM. The same phenomenon was induced by incubation with heat-killed B. abortus (HKBA) or the lipidated form of the 19-kDa outer membrane protein of Brucella (L-Omp19), and it was shown to be mediated by TLR2 recognition. In contrast, no significant downregulation of MHC-II was induced by either unlipidated Omp19 or Brucella LPS. In a functional assay, treatment of AM with either L-Omp19 or HKBA reduced the MHC-II-restricted presentation of OVA peptides to specific T cells. One week after intratracheal infection, viable B. abortus was detected in AM from both wild-type and TLR2 KO mice, but CFU counts were higher in the latter. These results suggest that B. abortus survives in AM after inhalatory infection in spite of a certain degree of immune control exerted by the TLR2-mediated inflammatory response. Both the modest nature of the latter and the modulation of MHC-II expression by the bacterium may contribute to such survival. PMID:24478078

  8. Key role of Toll-like receptor 2 in the inflammatory response and major histocompatibility complex class ii downregulation in Brucella abortus-infected alveolar macrophages.

    PubMed

    Ferrero, Mariana C; Hielpos, M Soledad; Carvalho, Natalia B; Barrionuevo, Paula; Corsetti, Patricia P; Giambartolomei, Guillermo H; Oliveira, Sergio C; Baldi, Pablo C

    2014-02-01

    Alveolar macrophages (AM) seem to constitute the main cellular target of inhaled brucellae. Here, we show that Brucella abortus invades and replicates in murine AM without inducing cytotoxicity. B. abortus infection induced a statistically significant increase of tumor necrosis factor alpha (TNF-α), CXCL1 or keratinocyte chemoattractant (KC), interleukin-1β (IL-1β), IL-6, and IL-12 in AM from C57BL/6 mice and BALB/c mice, but these responses were generally weaker and/or delayed compared to those elicited in peritoneal macrophages. Studies using knockout mice for TLR2, TLR4, and TLR9 revealed that TNF-α and KC responses were mediated by TLR2 recognition. Brucella infection reduced in a multiplicity of infection-dependent manner the expression of major histocompatibility complex class II (MHC-II) molecules induced by gamma interferon (IFN-γ) in AM. The same phenomenon was induced by incubation with heat-killed B. abortus (HKBA) or the lipidated form of the 19-kDa outer membrane protein of Brucella (L-Omp19), and it was shown to be mediated by TLR2 recognition. In contrast, no significant downregulation of MHC-II was induced by either unlipidated Omp19 or Brucella LPS. In a functional assay, treatment of AM with either L-Omp19 or HKBA reduced the MHC-II-restricted presentation of OVA peptides to specific T cells. One week after intratracheal infection, viable B. abortus was detected in AM from both wild-type and TLR2 KO mice, but CFU counts were higher in the latter. These results suggest that B. abortus survives in AM after inhalatory infection in spite of a certain degree of immune control exerted by the TLR2-mediated inflammatory response. Both the modest nature of the latter and the modulation of MHC-II expression by the bacterium may contribute to such survival. PMID:24478078

  9. Characterization and evolution of major histocompatibility complex class II genes in the aye-aye, Daubentonia madagascariensis.

    PubMed

    Go, Yasuhiro; Rakotoarisoa, Gilbert; Kawamoto, Yoshi; Shima, Taizo; Koyama, Naoki; Randrianjafy, Albert; Mora, Roger; Hirai, Hirohisa

    2005-04-01

    Major histocompatibility complex genes (Mhc-DQB and Mhc-DRB) were sequenced in seven aye-ayes (Daubentonia madagascariecsis), which is an endemic and endangered species in Madagascar. An aye-aye from a north-eastern population showed genetic relatedness to individuals of a north-western population and had a somewhat different repertoire from another north-eastern individual. These observations suggest that the extent of genetic variation in Mhc genes is not excessively small in the aye-aye in spite of recent rapid destruction of their habitat by human activities. In light of Mhc gene evolution, trans-species and allelic polymorphisms can be estimated to have been retained for more than 50 Ma (million years) based on the time scale of lemur evolution. PMID:15322927

  10. Dominating expression of negative regulatory factors downmodulates major histocompatibility complex Class-II expression on dendritic cells in chronic hepatitis C infection

    PubMed Central

    Tomer, Shallu; Chawla, Yogesh K; Duseja, Ajay; Arora, Sunil K

    2016-01-01

    AIM: To elucidate the molecular mechanisms leading to development of functionally impaired dendritic cells (DCs) in chronic hepatitis C (CHC) patients infected with genotype 3 virus. METHODS: This prospective study was conducted on the cohorts of CHC individuals identified as responders or non-responders to antiviral therapy. Myeloid DCs were isolated from the peripheral blood of each subject using CD1c (BDCA1)+ DC isolation Kit. Monocytes from healthy donor were cultured with DC growth factors such as IL-4 and GM-CSF either in the presence or absence of hepatitis C virus (HCV) viral proteins followed by LPS stimulation. Phenotyping was done by flowcytometry and gene expression profiling was evaluated by real-time PCR. RESULTS: Non-responders [sustained virological response (SVR)-ve] to conventional antiviral therapy had significantly higher expression of genes associated with interferon responsive element such as IDO1 and PD-L1 (6-fold) and negative regulators of JAK-STAT pathway such as SOCS (6-fold) as compared to responders (SVR+ve) to antiviral therapy. The down-regulated genes in non-responders included factors involved in antigen processing and presentation mainly belonging to major histocompatibility complex (MHC) Class-II family as HLA-DP, HLA-DQ (2-fold) and superoxide dismutase (2-fold). Cells grown in the presence of HCV viral proteins had genes down-regulated for factors involved in innate response, interferon signaling, DC maturation and co-stimulatory signaling to T-cells, while the genes for cytokine signaling and Toll-like receptors (4-fold) were up-regulated as compared to cells grown in absence of viral proteins. CONCLUSION: Underexpressed MHC class-II genes and upregulated negative regulators in non-responders indicate diminished capacity to present antigen and may constitute mechanism of functionally defective state of DCs. PMID:27298560

  11. Low Major Histocompatibility Complex Class II Variation in the Endangered Indo-Pacific Humpback Dolphin (Sousa chinensis): Inferences About the Role of Balancing Selection.

    PubMed

    Zhang, Xiyang; Lin, Wenzhi; Zhou, Ruilian; Gui, Duan; Yu, Xinjian; Wu, Yuping

    2016-03-01

    It has been widely reported that the major histocompatibility complex (MHC) is under balancing selection due to its immune function across terrestrial and aquatic mammals. The comprehensive studies at MHC and other neutral loci could give us a synthetic evaluation about the major force determining genetic diversity of species. Previously, a low level of genetic diversity has been reported among the Indo-Pacific humpback dolphin (Sousa chinensis) in the Pearl River Estuary (PRE) using both mitochondrial marker and microsatellite loci. Here, the expression and sequence polymorphism of 2 MHC class II genes (DQB and DRB) in 32 S. chinensis from PRE collected between 2003 and 2011 were investigated. High ratios of non-synonymous to synonymous substitution rates, codon-based selection analysis, and trans-species polymorphism (TSP) support the hypothesis that balancing selection acted on S. chinensis MHC sequences. However, only 2 haplotypes were detected at either DQB or DRB loci. Moreover, the lack of deviation from the Hardy-Weinberg expectation at DRB locus combined with the relatively low heterozygosity at both DQB locus and microsatellite loci suggested that balancing selection might not be sufficient, which further suggested that genetic drift associated with historical bottlenecks was not mitigated by balancing selection in terms of the loss of MHC and neutral variation in S. chinensis. The combined results highlighted the importance of maintaining the genetic diversity of the endangered S. chinensis. PMID:26787544

  12. Extensive polymorphism and evidence of selection pressure on major histocompatibility complex DLA-DRB1, DQA1 and DQB1 class II genes in Croatian grey wolves.

    PubMed

    Arbanasić, H; Huber, Đ; Kusak, J; Gomerčić, T; Hrenović, J; Galov, A

    2013-01-01

    The genes of the major histocompatibility complex (MHC) are a key component of the mammalian immune system and have become important molecular markers for measuring fitness-related genetic variation in wildlife populations. Because of human persecution and habitat fragmentation, the grey wolf has become extinct from a large part of Western and Central Europe, and remaining populations have become isolated. In Croatia, the grey wolf population, part of the Dinaric-Balkan population, shrank nearly to extinction during the 20th century, and is now legally protected. Using the cloning-sequencing method, we investigated the genetic diversity and evolutionary history of exon 2 of MHC class II DLA-DRB1, DQA1 and DQB1 genes in 77 individuals. We identified 13 DRB1, 7 DQA1 and 11 DQB1 highly divergent alleles, and 13 DLA-DRB1/DQA1/DQB1 haplotypes. Selection analysis comparing the relative rates of non-synonymous to synonymous mutations (d(N)/d(S)) showed evidence of positive selection pressure acting on all three loci. Trans-species polymorphism was found, suggesting the existence of balancing selection. Evolutionary codon models detected considerable difference between alpha and beta chain gene selection patterns: DRB1 and DQB1 appeared to be under stronger selection pressure, while DQA1 showed signs of moderate selection. Our results suggest that, despite the recent contraction of the Croatian wolf population, genetic variability in selectively maintained immune genes has been preserved. PMID:23134500

  13. Low Major Histocompatibility Complex Class II Variation in the Endangered Indo-Pacific Humpback Dolphin (Sousa chinensis): Inferences About the Role of Balancing Selection.

    PubMed

    Zhang, Xiyang; Lin, Wenzhi; Zhou, Ruilian; Gui, Duan; Yu, Xinjian; Wu, Yuping

    2016-03-01

    It has been widely reported that the major histocompatibility complex (MHC) is under balancing selection due to its immune function across terrestrial and aquatic mammals. The comprehensive studies at MHC and other neutral loci could give us a synthetic evaluation about the major force determining genetic diversity of species. Previously, a low level of genetic diversity has been reported among the Indo-Pacific humpback dolphin (Sousa chinensis) in the Pearl River Estuary (PRE) using both mitochondrial marker and microsatellite loci. Here, the expression and sequence polymorphism of 2 MHC class II genes (DQB and DRB) in 32 S. chinensis from PRE collected between 2003 and 2011 were investigated. High ratios of non-synonymous to synonymous substitution rates, codon-based selection analysis, and trans-species polymorphism (TSP) support the hypothesis that balancing selection acted on S. chinensis MHC sequences. However, only 2 haplotypes were detected at either DQB or DRB loci. Moreover, the lack of deviation from the Hardy-Weinberg expectation at DRB locus combined with the relatively low heterozygosity at both DQB locus and microsatellite loci suggested that balancing selection might not be sufficient, which further suggested that genetic drift associated with historical bottlenecks was not mitigated by balancing selection in terms of the loss of MHC and neutral variation in S. chinensis. The combined results highlighted the importance of maintaining the genetic diversity of the endangered S. chinensis.

  14. Allelic and haplotype variation of major histocompatibility complex class II DRB1 and DQB loci in the St Lawrence beluga (Delphinapterus leucas).

    PubMed

    1999-07-01

    In order to assess levels of major histocompatibility complex (Mhc) variation within the St Lawrence beluga (Delphinapterus leucas) the variation at the beluga Mhc DRB1 class II locus was assessed by single-strand conformation polymorphism (SSCP) analysis of the peptide-binding region for 313 whales collected from 13 sampling locations across North America. In addition, samples from west Greenland and the St Lawrence were also typed at the DQB locus, allowing comparison to a previous study and assessment of linkage disequilibrium of alleles at the two loci. Comparisons of DRB1 and DQB allele frequencies among all sampling locations indicated genetic structure (alpha < 0.005). Most of this structure resulted from differences between the different wintering groups. Significant genetic structure (alpha = 0.05) exists among each pair of the following groups at both the DRB1 and DQB loci; St Lawrence, Hudson Strait, Bering Sea, Cunningham Inlet, and Davis Strait (minus Cunningham Inlet), except the St Lawrence and Hudson Strait for the DQB locus. In the St Lawrence population, six of the eight DRB1 alleles are present representing all five known allelic lineages. Evidence of linkage disequilibrium between the DRB1 and DQB is present in two sampling locations, the St Lawrence and Nuussuaq (alpha = 0.05). Analysis of probable DRB1-DQB haplotypes among groups of beluga suggests a haplotype reduction in the St Lawrence. PMID:10447854

  15. Major histocompatibility complex class II DAB alleles associated with intestinal parasite load in the vulnerable Chinese egret (Egretta eulophotes).

    PubMed

    Lei, Wei; Zhou, Xiaoping; Fang, Wenzhen; Lin, Qingxian; Chen, Xiaolin

    2016-07-01

    The maintenance of major histocompatibility complex (MHC) polymorphism has been hypothesized to result from many mechanisms such as rare-allele advantage, heterozygote advantage, and allele counting. In the study reported herein, 224 vulnerable Chinese egrets (Egretta eulophotes) were used to examine these hypotheses as empirical results derived from bird studies are rare. Parasite survey showed that 147 (65.63%) individuals were infected with 1-3 helminths, and 82.31% of these infected individuals carried Ascaridia sp. Using asymmetric polymerase chain reaction technique, 10 DAB1, twelve DAB2, and three DAB3 exon 2 alleles were identified at each single locus. A significant association of the rare allele Egeu-DAB2*05 (allele frequency: 0.022) with helminth resistance was found for all helminths, as well as for the most abundant morphotype Ascaridia sp. in the separate analyses. Egeu-DAB2*05 occurred frequently in uninfected individuals, and individuals carrying Egeu-DAB2*05 had significantly lower helminth morphotypes per individual (HMI) (the number of HMI) and the fecal egg count values. Further, the parasite infection measurements were consistently lower in individuals with an intermediate number of different alleles in the duplicated DAB loci. Significantly, heterozygosity within each DAB locus was not correlated with any parasite infection measurements. These results indicate that the diversity in MHC Egeu-DAB gene is associated with intestinal parasite load and maintained by pathogen-driven selection that probably operate through both the rare-allele advantage and the allele counting strategy, and suggest that Egeu-DAB2*05 might be a valuable indicator of better resistance to helminth diseases in the vulnerable Chinese egret. PMID:27386085

  16. Disentangling the effects of recombination, selection, and demography on the genetic variation at a major histocompatibility complex class II gene in the alpine chamois.

    PubMed

    Mona, S; Crestanello, B; Bankhead-Dronnet, S; Pecchioli, E; Ingrosso, S; D'Amelio, S; Rossi, L; Meneguz, P G; Bertorelle, G

    2008-09-01

    The major histocompatibility complex (MHC) harbours some of the most polymorphic loci in vertebrate genomes. MHC genes are thought to be subject to some form of balancing selection, most likely pathogen-mediated selection. Hence, MHC genes are excellent candidates for exploring adaptive processes. In this study, we investigated the genetic variation at exon 2 of the DRB class II MHC locus in 191 alpine chamois (Rupicapra rupicapra) from 10 populations in the eastern Alps of Italy. In particular, we were interested in distinguishing and estimating the relative impact of selective and demographic factors, while taking into account the confounding effect of recombination. The extremely high d(n)/d(s) ratio and the presence of trans-species polymorphisms suggest that a strong long-term balancing selection effect has been operating at this locus throughout the evolutionary history of this species. We analysed patterns of genetic variation within and between populations, and the mitochondrial D-loop polymorphism patterns were analysed to provide a baseline indicator of the effects of demographic processes. These analyses showed that (i) the chamois experienced a demographic decline in the last 5000-30 000 years, most likely related to the postglacial elevation in temperature; (ii) this demographic process can explain the results of neutrality tests applied to MHC variation within populations, but cannot justify the much weaker divergence between populations implied by MHC as opposed to mitochondrial DNA; (iii) similar sets of divergent alleles are probably maintained with similar frequencies by balancing selection in different populations, and this mechanism is also operating in small isolated populations, which are strongly affected by drift.

  17. High-affinity binding of short peptides to major histocompatibility complex class II molecules by anchor combinations.

    PubMed Central

    Hammer, J; Belunis, C; Bolin, D; Papadopoulos, J; Walsky, R; Higelin, J; Danho, W; Sinigaglia, F; Nagy, Z A

    1994-01-01

    We have previously identified four anchor positions in HLA-DRB1*0101-binding peptides, and three anchors involved in peptide binding to DRB1*0401 and DRB1*1101 molecules, by screening of an M13 peptide display library (approximately 20 million independent nonapeptides) for DR-binding activity. In this study, high stringency screening of the M13 library for DRB1*0401 binding has resulted in identification of three further anchor positions. Taken together, a peptide-binding motif has been obtained, in which six of seven positions show enrichment of certain residues. We have demonstrated an additive effect of anchors in two different ways: (i) the addition of more anchors is shown to compensate for progressive truncation of designer peptides; (ii) the incorporation of an increasing number of anchors into 6- or 7-residue-long designer peptides is shown to result in a gradual increase of binding affinity to the level of 13-residue-long high-affinity epitopes. The anchor at relative position 1 seems to be obligatory, in that its substitution abrogates binding completely, whereas the elimination of other anchors results only in partial loss of binding affinity. The spacing between anchors is critical, since their effect is lost by shifting them one position toward the N or C terminus. The information born out of this study has been successfully used to identify DR-binding sequences from natural proteins. PMID:8183931

  18. Development of novel major histocompatibility complex class I and class II-deficient NOD-SCID IL2R gamma chain knockout mice for modeling human xenogeneic graft-versus-host disease.

    PubMed

    Pino, Steve; Brehm, Michael A; Covassin-Barberis, Laurence; King, Marie; Gott, Bruce; Chase, Thomas H; Wagner, Jennifer; Burzenski, Lisa; Foreman, Oded; Greiner, Dale L; Shultz, Leonard D

    2010-01-01

    Immunodeficient mice have been used as recipients of human peripheral blood mononuclear cells (PBMC) for in vivo analyses of human xeno-graft-versus-host disease (GVHD). This xeno-GVHD model system in many ways mimics the human disease. The model system is established by intravenous or intraperitoneal injection of human PBMC or spleen cells into unconditioned or irradiated immunodeficient recipient mice. Recently, the development of several stocks of immunodeficient Prkdc ( scid ) (scid) and recombination activating 1 or 2 gene (Rag1 or Rag2) knockout mice bearing a targeted mutation in the gene encoding the IL2 receptor gamma chain (IL2rgamma) have been reported. The addition of the mutated IL2rgamma gene onto an immunodeficient mouse stock facilitates heightened engraftment with human PBMC. Stocks of mice with mutations in the IL2rgamma gene have been studied in several laboratories on NOD-scid, NOD-Rag1 ( null ), BALB/c-Rag1 ( null ), BALB/c-Rag2 ( null ), and Stock-H2(d)-Rag2 ( null ) strain backgrounds. Parameters to induce human xeno-GVHD in H2(d)-Rag2 ( null ) IL2rgamma ( null ) mice have been published, but variability in the frequency of disease and kinetics of GVHD were observed. The availability of the NOD-scid IL2rgamma ( null ) stock that engrafts more readily with human PBMC than does the Stock-H2(d)-Rag2 ( null ) IL2rgamma ( null ) stock should lead to a more reproducible humanized mouse model of GVHD and for the use in drug evaluation and validation. Furthermore, GVHD in human PBMC-engrafted scid mice has been postulated to result predominately from a human anti-mouse major histocompatibility complex (MHC) class II reactivity. Our recent development of NOD-scid IL2rgamma ( null ) beta2m ( null ) and NOD-scid IL2rgamma ( null ) Ab ( null ) stocks of mice now make it possible to investigate directly the role of host MHC class I and class II in the pathogenesis of GVHD in humanized mice using NOD-scid IL2rgamma ( null ) stocks that engraft at high

  19. Selective immunosuppression by administration of major histocompatibility complex (MHC) class II-binding peptides. I. Evidence for in vivo MHC blockade preventing T cell activation

    PubMed Central

    1992-01-01

    Draining lymph node cells (LNC) from mice immunized with hen egg white lysozyme (HEL) display at their surface antigen-MHC complexes able to stimulate, in the absence of any further antigen addition, HEL peptide- specific, class II-restricted T cell hybridomas. Chloroquine addition to these LNC cultures fails to inhibit antigen presentation, indicating that antigenic complexes of class II molecules and HEL peptides are formed in vivo. MHC class II restriction of antigen presentation by LNC from HEL-primed mice was verified by the use of anti-class II monoclonal antibodies. Coinjection of HEL and the I-Ak-binding peptide HEL 112-129 in mice of H-2k haplotype inhibits the ability of LNC to stimulate I-Ak-restricted, HEL 46-61-specific T cell hybridomas. Similar results are obtained in mice coinjected with the HEL peptides 46-61 and 112-129. Inhibition of T hybridoma activation can also be observed using as antigen-presenting cells irradiated, T cell-depleted LNC from mice coinjected with HEL 46-61 and HEL 112-129, ruling out the possible role of either specific or nonspecific suppressor T cells. Inhibition of T cell proliferation is associated with MHC-specific inhibition of antigen presentation and with occupancy by the competitor of class II binding sites, as measured by activation of peptide- specific T cell hybridomas. These results demonstrate that administration of MHC class II binding peptide competitors selectively inhibits antigen presentation to class II-restricted T cells, indicating competitive blockade of class II molecules in vivo. PMID:1569402

  20. Human CD4-major histocompatibility complex class II (DQw6) transgenic mice in an endogenous CD4/CD8-deficient background: reconstitution of phenotype and human-restricted function

    PubMed Central

    1994-01-01

    To reconstitute the human immune system in mice, transgenic mice expressing human CD4 and human major histocompatibility complex (MHC) class II (DQw6) molecules in an endogenous CD4- and CD8-deficient background (mCD4/8-/-), after homologous recombination, have been generated. We report that expression of human CD4 molecule in mCD4/8-/- mice rescues thymocyte development and completely restores the T cell compartment in peripheral lymphoid organs. Upon vesicular stomatitis virus (VSV) challenge, the reconstituted mature T cell population effectively provide T help to B cells in immunoglobulin class switching from IgM to specific IgG-neutralizing antibodies. Human CD4+DQw6+ double transgenic mice are tolerant to DQw6 and the DQw6 molecule functions in antigen presentation, effectively generating a human MHC class II-restricted T cell response to streptococcal M6C2 peptide. These data show that both the hCD4 and DQw6 molecules are functional in mCD4/8-/- mice, fully and stably reconstituting this limb of the human immune system in mice. This animal model provides a powerful in vivo tool to dissect the human CD4-human class II MHC interaction, especially its role in human autoimmune diseases, superantigen-mediated diseases, and acquired immunodeficiency syndrome (AIDS). PMID:7964466

  1. Trypanosoma cruzi Infection Modulates In Vivo Expression of Major Histocompatibility Complex Class II Molecules on Antigen-Presenting Cells and T-Cell Stimulatory Activity of Dendritic Cells in a Strain-Dependent Manner

    PubMed Central

    Alba Soto, Catalina D.; Mirkin, Gerardo A.; Solana, Maria E.; González Cappa, Stella M.

    2003-01-01

    A striking feature of Chagas' disease is the diversity of clinical presentations. Such variability may be due to the heterogeneity among Trypanosoma cruzi isolates or to the host immune response. Employing two strains which differ in their virulence, we investigated the effect of in vivo infection on professional antigen-presenting cells (APC). Acute infection with the virulent RA strain downregulated the expression of major histocompatibility complex (MHC) class II on splenic dendritic cells (DC) and inhibited its induction on peritoneal macrophages and splenic B cells. It also impaired the ability of DC to prime allogeneic T cells and to form homotypic clusters, suggesting a low maturation state of these cells. In contrast, the low-virulence K98 strain maintained the expression of MHC class II on DC or stimulated it on peritoneal macrophages and B cells and preserved DC's T-cell priming capacity and homotypic clustering. DC from RA-infected mice elicited a lower activation of T. cruzi-specific T-cell proliferation than those from K98-infected mice. APC from RA-infected mice that reached the chronic phase of infection restored MHC class II levels to those found in K98-infected mice and upregulated costimulatory molecules expression, suggesting that the immunosuppression caused by this strain is only transient. Taken together, the results indicate that in vivo infection with T. cruzi modulates APC functionality and that this is accomplished in a strain-dependent manner. PMID:12595432

  2. A synthetic random basic copolymer with promiscuous binding to class II major histocompatibility complex molecules inhibits T-cell proliferative responses to major and minor histocompatibility antigens in vitro and confers the capacity to prevent murine graft-versus-host disease in vivo.

    PubMed Central

    Schlegel, P G; Aharoni, R; Chen, Y; Chen, J; Teitelbaum, D; Arnon, R; Sela, M; Chao, N J

    1996-01-01

    Graft-versus-host disease (GVHD) is a T-cell-mediated disease of transplanted donor T cells recognizing host alloantigens. Data presented in this report show, to our knowledge, for the first time that a synthetic copolymer of the amino acids L-Glu, L-Lys, L-Ala, and L-Tyr (molecular ratio, 1.9:6.0:4.7:1.0; Mr, 6000-8500) [corrected], termed GLAT, with promiscuous binding to multiple major histocompatibility complex class II alleles is capable of preventing lethal GVHD in the B10.D2 --> BALB/c model (both H-2d) across minor histocompatibility barriers. Administration of GLAT over a limited time after transplant significantly reduced the incidence, onset, and severity of disease. GLAT also improved long-term survival from lethal GVHD: 14/25 (56%) of experimental mice survived > 140 days after transplant compared to 2/26 of saline-treated or to 1/10 of hen egg lysozyme-treated control mice (P < 0.01). Long-term survivors were documented to be fully chimeric by PCR analysis of a polymorphic microsatellite region in the interleukin 1beta gene. In vitro, GLAT inhibited the mixed lymphocyte culture in a dose-dependent fashion across a variety of major barriers tested. Furthermore, GLAT inhibited the response of nylon wool-enriched T cells to syngeneic antigen-presenting cells presenting minor histocompatibility antigens. Prepulsing of the antigen-presenting cells with GLAT reduced the proliferative response, suggesting that GLAT inhibits antigen presentation. Images Fig. 1 Fig. 2 Fig. 4 PMID:8643529

  3. Correction of the X-linked immunodeficiency phenotype by transgenic expression of human Bruton tyrosine kinase under the control of the class II major histocompatibility complex Ea locus control region

    PubMed Central

    Drabek, Dubravka; Raguz, Selina; De Wit, Ton P. M.; Dingjan, Gemma M.; Savelkoul, Huub F. J.; Grosveld, Frank; Hendriks, Rudolf W.

    1997-01-01

    Bruton tyrosine kinase (Btk) is essential for the development of pre-B cells to mature B cell stages. Btk-deficient mice manifest an X-linked immunodeficiency (xid) defect characterized by a reduction of peripheral IgMlow IgDhigh B cells, a lack of peritoneal CD5+ B cells, low serum levels of IgM and IgG3, and impaired responses to T cell independent type II (TI-II) antigens. We have generated transgenic mice in which expression of the human Btk gene is driven by the murine class II major histocompatibility complex Ea gene locus control region, which provides gene expression from the pre-B cell stage onwards. When these transgenic mice were mated onto a Btk− background, correction of the xid B cell defects was observed: B cells differentiated to mature IgMlowIgDhigh stages, peritoneal CD5+ B cells were present, and serum Ig levels and in vivo responses to TI-II antigens were in the normal ranges. A comparable rescue by transgenic Btk expression was also observed in heterozygous Btk+/− female mice in those B-lineage cells that were Btk-deficient as a result of X chromosome inactivation. These findings indicate that the Btk− phenotype in the mouse can be corrected by expression of human Btk from the pre-B cell stage onwards. PMID:9012832

  4. T cell stimulation by staphylococcal enterotoxins. Clonally variable response and requirement for major histocompatibility complex class II molecules on accessory or target cells

    PubMed Central

    1988-01-01

    Staphylococcal enterotoxins (SE) are the most potent mitogens for T lymphocytes known; concentrations of less than 10(-9) M are sufficient for T cell activation. The mechanism of T cell activation by SE is unknown. We have used cloned human cytotoxic and proliferative T lymphocytes to dissect the molecular mechanism of T cell activation by SE. With rare exceptions, all TCR alpha/beta chain-expressing T cell clones of CD4+ or CD8+ phenotype, as well as CD4-8- TCR alpha/beta chain negative chain-expressing T lymphocyte clones, respond with proliferation and/or cytotoxicity to SE. For triggering of all these clones, the presence of autologous or allogeneic MHC class II molecules on accessory or target cells is necessary. This requirement for class II antigens is not due to an immunological recognition of processed SE, since inhibition of antigen processing has no influence on the T cell response to SE. SE acts on the T cells directly since (a) they stimulate a rise in intracellular calcium concentration in T cell lines or purified T cells, and (b) accessory cells can be replaced by phorbolesters in the proliferative activation of resting T cells by SE. Furthermore, the T cell response to SE shows extensive clonal heterogeneity. These results suggest that SE are functionally bivalent mitogens binding highly selectively to HLA class II molecules and the TCR. Thus, compared with other polyclonal T cell activating agents, activation with SE most closely mimicks the physiological way of MHC- restricted antigen recognition by T lymphocytes. PMID:3259256

  5. Brief Note Low diversity of the major histocompatibility complex class II DRA gene in domestic goats (Capra hircus) in Southern China.

    PubMed

    Chen, L P; E, G X; Zhao, Y J; Na, R S; Zhao, Z Q; Zhang, J H; Ma, Y H; Sun, Y W; Zhong, T; Zhang, H P; Huang, Y F

    2015-01-01

    DRA encodes the alpha chain of the DR heterodimer, is closely linked to DRB and is considered almost monomorphic in major histocompatibility complex region. In this study, we identified the exon 2 of DRA to evaluate the immunogenetic diversity of Chinese south indigenous goat. Two single nucleotide polymorphisms in an untranslated region and one synonymous substitution in coding region were identified. These data suggest that high immunodiversity in native Chinese population. PMID:26125900

  6. Molecular characterization by high-resolution isoelectric focusing of the products encoded by the class II region loci of the major histocompatibility complex in humans. I. DR and DQ gene variants.

    PubMed

    Rodriguez de Cordoba, S; Nunez-Roldan, A; Winchester, R; Marshall, P; Carrier, C; Mollen, N; Walker, M; Ginsberg-Fellner, F; Rubinstein, P

    1987-09-01

    We describe a new approach to the analysis of the structural polymorphism of the DR beta, DQ alpha, and DQ beta polypeptide chains of human histocompatibility class II antigens. In comparison to conventional two-dimensional gel studies, this method provides sharper definition of the protein bands and side-by-side comparisons within the same gel, thereby permitting the detection of minor differences in the isoelectric points of the protein chains. Using this methodology we have analyzed the IEF polymorphism and the variability in the number of the DR beta chains encoded by different DR haplotypes. Twenty DR beta chain variants, which include the products of no less than two separate DR beta loci, have been thus far identified. Alleles at one of these loci are assumed to code for DR beta chains carrying the DR alloespecificities DR1, DR2, DR3, DR4, DR5, DRw6, DR7, and DR8. Alleles at a second DR beta locus encode DR beta chains that may be shared by serologically DR-different haplotypes and carry supertypic serologic specificities (i.e., DRw52 and DRw53). We also demonstrate here that the structural polymorphisms of the DQ alpha and DQ beta chains are more extensive than previously thought, report the characterization of 14 DQ beta variants, and define their relationship to the previously described DQw serologic specificities. In addition, we describe the class II haplotype associations observed for the different DR and DQ variants characterized. PMID:3679903

  7. Dectin-1-triggered Recruitment of Light Chain 3 Protein to Phagosomes Facilitates Major Histocompatibility Complex Class II Presentation of Fungal-derived Antigens*

    PubMed Central

    Ma, Jun; Becker, Courtney; Lowell, Clifford A.; Underhill, David M.

    2012-01-01

    Dectin-1 is a pattern recognition receptor that is important for innate immune responses against fungi in humans and mice. Dectin-1 binds to β-glucans in fungal cell walls and triggers phagocytosis, production of reactive oxygen by the NADPH oxidase, and inflammatory cytokine production which all contribute to host immune responses against fungi. Although the autophagy pathway was originally characterized for its role in the formation of double-membrane compartments engulfing cytosolic organelles and debris, recent studies have suggested that components of the autophagy pathway may also participate in traditional phagocytosis. In this study, we show that Dectin-1 signaling in macrophages and bone marrow-derived dendritic cells triggers formation of LC3II, a major component of the autophagy machinery. Further, Dectin-1 directs the recruitment of LC3II to phagosomes, and this requires Syk, activation of reactive oxygen production by the NADPH oxidase, and ATG5. Using LC3-deficient dendritic cells we show that whereas LC3 recruitment to phagosomes is not important for triggering phagocytosis, killing or Dectin-1-mediated inflammatory cytokine production, it facilitates recruitment of MHC class II molecules to phagosomes and promotes presentation of fungal-derived antigens to CD4 T cells. PMID:22902620

  8. Reassociation with beta 2-microglobulin is necessary for Kb class I major histocompatibility complex binding of exogenous peptides.

    PubMed Central

    Rock, K L; Rothstein, L E; Gamble, S R; Benacerraf, B

    1990-01-01

    T lymphocytes recognize endogenously produced antigenic peptides in association with major histocompatibility complex (MHC)-encoded molecules. Peptides from the extracellular fluid can be displayed in association with class I and class II MHC molecules. Here we report that mature Kb class I MHC molecules bind peptides upon dissociation and reassociation of their light chain. Intact Kb heterodimers, unlike class II MHC molecules, are relatively unreceptive to binding peptides. This property may maintain segregation of class I and class II MHC-restricted peptides and has implications for the use of peptides as vaccines. Images PMID:2217182

  9. Major histocompatibility complex class II polymorphisms are associated with the development of anti-resorptive agent-induced osteonecrosis of the jaw.

    PubMed

    Stockmann, Philipp; Nkenke, Emeka; Englbrecht, Matthias; Schlittenbauer, Tilo; Wehrhan, Falk; Rauh, Claudia; Beckmann, Matthias W; Fasching, Peter A; Kreusch, Thomas; Mackensen, Andreas; Wullich, Bernd; Schett, Georg; Spriewald, Bernd M

    2013-01-01

    The aetiology of anti-resorptive agent-induced osteonecrosis of the jaw (ARONJ) is still under debate. Clinical and genetic risk factors are currently being investigated to help understand its pathogenesis. This case-control study analysed a large number of cancer patients (n = 230) under therapy with intravenous bisphosphonates, half of which were diagnosed with ARONJ. Multiple myeloma, greater patient age and the use of more than one bisphosphonate were identified as clinical risk factors on logistic regression analysis. In addition, 204 patients were genotyped for HLA-DRB1 and DQB1 and the allele frequencies were compared between ARONJ (n = 94) and unaffected cancer patients (n = 110). For the HLA class II alleles, a strong increase in the frequency of DRB1*15, DQB1*06:02, DRB1*01 and DQB1*05:01 was observed in the ARONJ group. These results were reinforced on analysis of the respective haplotypes, with DRB1*15-DQB1*06:02 being significantly associated with the development of ARONJ (odds ratio [OR] 2.5; 95% confidence interval [CI] 1.3-5.0). The presence of at least one of the haplotypes DRB1*15-DQB1*06:02 and DRB1*01-DQB1*05:01 was highly associated with the development of ARONJ (OR 3.0; 95% CI 1.7-5.5). The data in this study of a large number of cancer patients receiving intravenous bisphosphonates suggest that MHC class II polymorphisms represent genetic risk factors for the development of ARONJ. This result supports recent findings that inflammation and infection might play an important role in the pathogenesis of ARONJ.

  10. Combination of the histone deacetylase inhibitor depsipeptide and 5-fluorouracil upregulates major histocompatibility complex class II and p21 genes and activates caspase-3/7 in human colon cancer HCT-116 cells

    PubMed Central

    Okada, Kouji; Hakata, Shuko; Terashima, Jun; Gamou, Toshie; Habano, Wataru; Ozawa, Shogo

    2016-01-01

    Epigenetic anticancer drugs such as histone deacetylase (HDAC) inhibitors have been combined with existing anticancer drugs for synergistic or additive effects. In the present study, we found that a very low concentration of depsipeptide, an HDAC inhibitor, potentiated the antitumor activity of 5-fluorouracil (5-FU) in a human colon cancer cell model using HCT-116, HT29, and SW48 cells via the inhibition of colony formation ability or cellular viability. Exposure to a combination of 5-FU (1.75 µM) and 1 nM depsipeptide for 24 and 48 h resulted in a 3- to 4-fold increase in activated caspase-3/7, while 5-FU alone failed to activate caspase-3/7. Microarray and subsequent gene ontology analyses revealed that compared to 5-FU or depsipeptide alone, the combination treatment of 5-FU and depsipeptide upregulated genes related to cell death and the apoptotic process consistent with the inhibition of colony formation and caspase-3/7 activation. These analyses indicated marked upregulation of antigen processing and presentation of peptide or polysaccharide antigen via major histocompatibility complex (MHC) class (GO:0002504) and MHC protein complex (GO:0042611). Compared with vehicle controls, the cells treated with the combination of 5-FU and depsipeptide showed marked induction (3- to 8.5-fold) of expression of MHC class II genes, but not of MHC class I genes. Furthermore, our global analysis of gene expression, which was focused on genes involved in the molecular regulation of MHC class II genes, showed enhancement of pro-apoptotic PCAF and CIITA after the combination of 5-FU and depsipeptide. These results may indicate a closer relationship between elevation of MHC class II expression and cellular apoptosis induced by the combination of depsipeptide and 5-FU. To the best of our knowledge, this is the first study to report that the combination of 5-FU and depsipeptide induces human colon cancer cell apoptosis in a concerted manner with the induction of MHC class II gene

  11. Combination of the histone deacetylase inhibitor depsipeptide and 5-fluorouracil upregulates major histocompatibility complex class II and p21 genes and activates caspase-3/7 in human colon cancer HCT-116 cells.

    PubMed

    Okada, Kouji; Hakata, Shuko; Terashima, Jun; Gamou, Toshie; Habano, Wataru; Ozawa, Shogo

    2016-10-01

    Epigenetic anticancer drugs such as histone deacetylase (HDAC) inhibitors have been combined with existing anticancer drugs for synergistic or additive effects. In the present study, we found that a very low concentration of depsipeptide, an HDAC inhibitor, potentiated the antitumor activity of 5-fluorouracil (5-FU) in a human colon cancer cell model using HCT-116, HT29, and SW48 cells via the inhibition of colony formation ability or cellular viability. Exposure to a combination of 5-FU (1.75 µM) and 1 nM depsipeptide for 24 and 48 h resulted in a 3- to 4-fold increase in activated caspase-3/7, while 5-FU alone failed to activate caspase-3/7. Microarray and subsequent gene ontology analyses revealed that compared to 5-FU or depsipeptide alone, the combination treatment of 5-FU and depsipeptide upregulated genes related to cell death and the apoptotic process consistent with the inhibition of colony formation and caspase-3/7 activation. These analyses indicated marked upregulation of antigen processing and presentation of peptide or polysaccharide antigen via major histocompatibility complex (MHC) class (GO:0002504) and MHC protein complex (GO:0042611). Compared with vehicle controls, the cells treated with the combination of 5-FU and depsipeptide showed marked induction (3- to 8.5-fold) of expression of MHC class II genes, but not of MHC class I genes. Furthermore, our global analysis of gene expression, which was focused on genes involved in the molecular regulation of MHC class II genes, showed enhancement of pro-apoptotic PCAF and CIITA after the combination of 5-FU and depsipeptide. These results may indicate a closer relationship between elevation of MHC class II expression and cellular apoptosis induced by the combination of depsipeptide and 5-FU. To the best of our knowledge, this is the first study to report that the combination of 5-FU and depsipeptide induces human colon cancer cell apoptosis in a concerted manner with the induction of MHC

  12. The Missing Link in Epstein-Barr Virus Immune Evasion: the BDLF3 Gene Induces Ubiquitination and Downregulation of Major Histocompatibility Complex Class I (MHC-I) and MHC-II

    PubMed Central

    Quinn, Laura L.; Williams, Luke R.; White, Claire; Forrest, Calum; Rowe, Martin

    2015-01-01

    ABSTRACT The ability of Epstein-Barr virus (EBV) to spread and persist in human populations relies on a balance between host immune responses and EBV immune evasion. CD8+ cells specific for EBV late lytic cycle antigens show poor recognition of target cells compared to immediate early and early antigen-specific CD8+ cells. This phenomenon is due in part to the early EBV protein BILF1, whose immunosuppressive activity increases with lytic cycle progression. However, published data suggest the existence of a hitherto unidentified immune evasion protein further enhancing protection against late EBV antigen-specific CD8+ cells. We have now identified the late lytic BDLF3 gene as the missing link accounting for efficient evasion during the late lytic cycle. Interestingly, BDLF3 also contributes to evasion of CD4+ cell responses to EBV. We report that BDLF3 downregulates expression of surface major histocompatibility complex (MHC) class I and class II molecules in the absence of any effect upon other surface molecules screened, including CD54 (ICAM-1) and CD71 (transferrin receptor). BDLF3 both enhanced internalization of surface MHC molecules and reduced the rate of their appearance at the cell surface. The reduced expression of surface MHC molecules correlated with functional protection against CD8+ and CD4+ T cell recognition. The molecular mechanism was identified as BDLF3-induced ubiquitination of MHC molecules and their subsequent downregulation in a proteasome-dependent manner. IMPORTANCE Immune evasion is a necessary feature of viruses that establish lifelong persistent infections in the face of strong immune responses. EBV is an important human pathogen whose immune evasion mechanisms are only partly understood. Of the EBV immune evasion mechanisms identified to date, none could explain why CD8+ T cell responses to late lytic cycle genes are so infrequent and, when present, recognize lytically infected target cells so poorly relative to CD8+ T cells specific for

  13. A mouse aminopeptidase N is a marker for antigen-presenting cells and appears to be co-expressed with major histocompatibility complex class II molecules.

    PubMed

    Hansen, A S; Norén, O; Sjöström, H; Werdelin, O

    1993-09-01

    To analyze the expression of mouse aminopeptidase N (APN) on the cells of the immune system a panel of rat monoclonal antibodies against mouse intestinal APN was generated. These antibodies were used to affinity purify functional mouse APN from both intestine and kidney, and by flow cytometry to examine the APN expression of the cells of the mouse immune system. An APN closely related, perhaps identical, to the intestinal APN was expressed on a subpopulation of spleen cells and stimulated peritoneal exudate cells, primarily representing antigen-presenting cells, such as B cells, macrophages, dendritic cells, and veiled cells. In contrast this APN expression could not be detected on thymocytes or spleen T cells. As a corollary, APN was expressed on monocyte, macrophage, and B lymphoma cell lines, but not on T hybridoma or thymoma cell lines. The expression of APN showed a striking correlation with the MHC class II expression in all the cell populations studied. This apparent co-expression suggests a role for APN in antigen processing.

  14. Major Histocompatibility Complex class IIB polymorphism in an ancient Spanish breed.

    PubMed

    Atlija, Marina; Gutíerrez-Gil, Beatriz; Arranz, Juan-Jose; Semmer, Jördis; Stear, Michael J; Buitkamp, Johannes

    2015-09-01

    Genes from the Major Histocompatibility Complex class II region are involved in the presentation of antigens. Therefore, they have the key role in regulating the immune response and in the resistance to infections. We investigated the Major Histocompatibility Complex class IIB genes, DRB and DQB, in Churra sheep, one of the most important indigenous breeds of Spain. These genes are among the most polymorphic in the mammalian genome. Furthermore, often different numbers of class IIB genes per haplotype exist, complicating the genotyping and sequencing of these genes. Especially the DQB region is only partially characterized in sheep and the repertoire of DRB and DQB alleles in Churra sheep, an ancient breed, is unknown. Here, we sequenced the class IIB genes for 15 rams that are the pedigree heads of a selection Nucleus herd. In total, we found 12 DRB and 25 DQB alleles. From these, 3 and 15 were new, respectively. Fourteen haplotypes carrying one or two DQB alleles could be deduced and the evolutionary relationship of these was investigated by phylogenetic trees. Based on the sequences of these most common class II alleles, a more efficient genotyping system for larger numbers of Churra sheep will be developed. PMID:26184839

  15. Assessment of biodiversity in Chilean cattle using the distribution of major histocompatibility complex class II BoLA-DRB3 allele.

    PubMed

    Takeshima, S-N; Miyasaka, T; Matsumoto, Y; Xue, G; Diaz, V de la Barra; Rogberg-Muñoz, A; Giovambattista, G; Ortiz, M; Oltra, J; Kanemaki, M; Onuma, M; Aida, Y

    2015-01-01

    Bovine leukocyte antigens (BoLAs) are used extensively as markers for bovine disease and immunological traits. In this study, we estimated BoLA-DRB3 allele frequencies using 888 cattle from 10 groups, including seven cattle breeds and three crossbreeds: 99 Red Angus, 100 Black Angus, 81 Chilean Wagyu, 49 Hereford, 95 Hereford × Angus, 71 Hereford × Jersey, 20 Hereford × Overo Colorado, 113 Holstein, 136 Overo Colorado, and 124 Overo Negro cattle. Forty-six BoLA-DRB3 alleles were identified, and each group had between 12 and 29 different BoLA-DRB3 alleles. Overo Negro had the highest number of alleles (29); this breed is considered in Chile to be an 'Old type' European Holstein Friesian descendant. By contrast, we detected 21 alleles in Holstein cattle, which are considered to be a 'Present type' Holstein Friesian cattle. Chilean cattle groups and four Japanese breeds were compared by neighbor-joining trees and a principal component analysis (PCA). The phylogenetic tree showed that Red Angus and Black Angus cattle were in the same clade, crossbreeds were closely related to their parent breeds, and Holstein cattle from Chile were closely related to Holstein cattle in Japan. Overall, the tree provided a thorough description of breed history. It also showed that the Overo Negro breed was closely related to the Holstein breed, consistent with historical data indicating that Overo Negro is an 'Old type' Holstein Friesian cattle. This allelic information will be important for investigating the relationship between major histocompatibility complex (MHC) and disease.

  16. Balancing selection and genetic drift at major histocompatibility complex class II genes in isolated populations of golden snub-nosed monkey (Rhinopithecus roxellana)

    PubMed Central

    2012-01-01

    Background Small, isolated populations often experience loss of genetic variation due to random genetic drift. Unlike neutral or nearly neutral markers (such as mitochondrial genes or microsatellites), major histocompatibility complex (MHC) genes in these populations may retain high levels of polymorphism due to balancing selection. The relative roles of balancing selection and genetic drift in either small isolated or bottlenecked populations remain controversial. In this study, we examined the mechanisms maintaining polymorphisms of MHC genes in small isolated populations of the endangered golden snub-nosed monkey (Rhinopithecus roxellana) by comparing genetic variation found in MHC and microsatellite loci. There are few studies of this kind conducted on highly endangered primate species. Results Two MHC genes were sequenced and sixteen microsatellite loci were genotyped from samples representing three isolated populations. We isolated nine DQA1 alleles and sixteen DQB1 alleles and validated expression of the alleles. Lowest genetic variation for both MHC and microsatellites was found in the Shennongjia (SNJ) population. Historical balancing selection was revealed at both the DQA1 and DQB1 loci, as revealed by excess non-synonymous substitutions at antigen binding sites (ABS) and maximum-likelihood-based random-site models. Patterns of microsatellite variation revealed population structure. FST outlier analysis showed that population differentiation at the two MHC loci was similar to the microsatellite loci. Conclusions MHC genes and microsatellite loci showed the same allelic richness pattern with the lowest genetic variation occurring in SNJ, suggesting that genetic drift played a prominent role in these isolated populations. As MHC genes are subject to selective pressures, the maintenance of genetic variation is of particular interest in small, long-isolated populations. The results of this study may contribute to captive breeding and translocation programs

  17. A mutational analysis of the Abetaz/Aalphad major histocompatibility complex class II molecule that restricts autoreactive T cells in (NZBxNZW)F1 mice. The critical influence of alanine at position 69 in the Aalphad chain.

    PubMed

    Sai, T; Mine, M; Fukuoka, M; Koarada, S; Kimoto, M

    1999-03-01

    Autoimmune symptoms of (NZBxNZW)F1 (H-2d/z) mice are reported to be critically related to the heterozygosity at the H-2 complex of the murine major histocompatibility complex (MHC). We previously showed that several Abetaz/Aalphad MHC class II molecule-restricted autoreactive T-cell clones from B/WF1 mice were pathogenic upon transfer to preautoimmune B/WF1 mice. In this study, to identify the crucial amino acid residues in Abetaz/Aalphad molecules for T-cell activation, we generated a panel of transfectant cell lines. These transfectant cell lines express the Abetaz/Aalphad MHC molecules with a mutation at each residue alpha11, alpha28, alpha57, alpha69, alpha70, alpha76 of Aalphad chain and beta86 of Abetaz chain. Replacing alpha69 alanine with threonine, valine or serine completely eliminated the ability to stimulate autoreactive T-cell clones without affecting the ability to present foreign antigen keyhole limpet haemocyanin (KLH) or L-plastin peptide to specific T-cell clones. Replacing beta86 valine with aspartic acid resulted in a decrease in the stimulation for antigen-reactive as well as autoreactive T-cell clones. Substitutions at other residues had minimal or no effect on the stimulation of either auto- or antigen-reactive T-cell clones. These results suggest that alanine at residue 69 of the Aalphad chain is critical for the activation of autoreactive Abetaz/Aalphad-restricted T-cell clones. Possible explanations for this are discussed. PMID:10233712

  18. Identification of the transcription factors NF-YA and NF-YB as factors A and B that bound to the promoter of the major histocompatibility complex class II gene I-A beta.

    PubMed Central

    Celada, A; McKercher, S R; Maki, R A

    1996-01-01

    The Y box is a conserved sequence in the promoter of major histocompatibility complex (MHC) class II genes, which contains a CCAAT sequence (CCAAT box). Previously, we partially purified the DNA-binding protein that recognizes the Y box of the I-A beta gene and showed that it consisted of two components (factors A and B) both of which were necessary for optimal DNA binding. The genes for the heteromeric protein NF-Y (NF-YA and NF-YB), which binds to the I-E alpha Y box have been cloned. We subsequently isolated the genes for NF-YA and NF-YB using oligonucleotides designed from the published sequences. NF-YA and NF-YB were tested for binding to the I-A beta and I-E alpha Y boxes. While neither NF-YA or NF-YB alone bound to the Y box, when the components were mixed the complex bound to the I-A beta Y box with high affinity. Moreover, NF-YA and NF-YB could be complemented for binding to DNA by factor B or factor A, respectively. These results suggest that the active binding protein is NF-YA in factor A extracts and NF-YB in factor B extracts. Finally, antibodies against NF-YA and NF-YB were shown to induce a supershift when nuclear extracts were added to the double-stranded oligodeoxynucleotide covering the Y box of the I-A beta gene. Antisense expression constructs of both NF-YA and NF-YB were made and their effect on expression from the I-A beta promoter was tested. Either antisense construction, when transfected into cells, lowered the expression of a reporter gene linked to the I-A beta promoter. This study provides direct evidence of the identification of NF-YA and NF-YB as the previously described factors A and B. Moreover, these results strongly implicate NF-Y in the expression of the MHC class II gene I-A beta. PMID:8760361

  19. Major histocompatibility complex class I-restricted alloreactive CD4+ T cells.

    PubMed

    Boyle, Louise H; Goodall, Jane C; Gaston, J S Hill

    2004-05-01

    Although it is well established that CD4+ T cells generally recognize major histocompatibility complex (MHC) class II molecules, MHC class I-reactive CD4+ T cells have occasionally been reported. Here we describe the isolation and characterization of six MHC class I-reactive CD4+ T-cell lines, obtained by co-culture of CD4+ peripheral blood T cells with the MHC class II-negative, transporter associated with antigen processing (TAP)-negative cell line, T2, transfected with human leucocyte antigen (HLA)-B27. Responses were inhibited by the MHC class I-specific monoclonal antibody (mAb), W6/32, demonstrating the direct recognition of MHC class I molecules. In four cases, the restriction element was positively identified as HLA-A2, as responses by these clones were completely inhibited by MA2.1, an HLA-A2-specific mAb. Interestingly, three of the CD4+ T-cell lines only responded to cells expressing HLA-B27, irrespective of their restricting allele, implicating HLA-B27 as a possible source of peptides presented by the stimulatory MHC class I alleles. In addition, these CD4+ MHC class I alloreactive T-cell lines could recognize TAP-deficient cells and therefore may have particular clinical relevance to situations where the expression of TAP molecules is decreased, such as viral infection and transformation of cells. PMID:15096184

  20. Analysis of T cell stimulation by superantigen plus major histocompatibility complex class II molecules or by CD3 monoclonal antibody: costimulation by purified adhesion ligands VCAM-1, ICAM-1, but not ELAM-1

    PubMed Central

    1991-01-01

    Many ligands of adhesion molecules mediate costimulation of T cell activation. The generality of this emerging concept is best determined by using model systems which exploit physiologically relevant ligands. We developed such an "antigen-specific" model system for stimulation of resting CD4+ human T cells using the following purified ligands: (a) major histocompatibility complex class II plus the superantigen Staphylococcus enterotoxin A, to engage the T cell receptor (TCR); (b) adhesion proteins vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), and endothelial leukocyte adhesion molecule 1 (ELAM-1), to provide potential cell surface costimulatory signals; and (c) recombinant interleukin 1 beta (rIL-1 beta)/rIL-6 as costimulatory cytokines. In this biochemically defined system, we find that resting CD4+ T cells require costimulation in order to respond to TCR engagement. This costimulation can be provided by VCAM-1 or ICAM-1; however adhesion alone is not sufficient since ELAM-1 mediates adhesion but not costimulation. The cytokines IL-1 beta and IL-6 by themselves cannot mediate costimulation, but augment the adhesion ligand-mediated costimulation. Direct comparison with the model of TCR/CD3 engagement by CD3 monoclonal antibody demonstrated comparable costimulatory requirements in both systems, thereby authenticating the commonly used CD3 model. The costimulation mediated by the activation-dependent interaction of the VLA-4 and LFA-1 integrins with their respective ligands VCAM-1 and ICAM-1 leads to increased IL-2R alpha (CD25) expression and proliferation in both CD45RA+ CD4+ and CD45RO+ CD4+ T cells. The integrins also regulate the secretion of IL-2, IL-4, and granulocyte/macrophage colony-stimulating factor. In contrast the activation-independent adhesion of CD4+ T cell to ELAM-1 molecules does not lead to T cell stimulation as measured by proliferation, IL-2R alpha expression, or cytokine release. These findings imply

  1. Cytokines Regulate Proteolysis in Major Histocompatibility Complex Class II–Dependent Antigen Presentation by Dendritic Cells

    PubMed Central

    Fiebiger, Edda; Meraner, Paul; Weber, Ekkehard; Fang, I-Fei; Stingl, Georg; Ploegh, Hidde; Maurer, Dieter

    2001-01-01

    Endo/lysosomal proteases control two key events in antigen (Ag) presentation: the degradation of protein Ag and the generation of peptide-receptive major histocompatibility complex (MHC) class II molecules. Here we show that the proinflammatory cytokines tumor necrosis factor α and interleukin (IL)-1β rapidly increase the activity of cathepsin (cat) S and catB in human dendritic cells (DCs). As a consequence, a wave of MHC class II sodium dodecyl sulfate stable dimer formation ensues in a catS-dependent fashion. In contrast, the antiinflammatory cytokine IL-10 renders DCs incapable of upregulating catS and catB activity and in fact, attenuates the level of both enzymes. Suppressed catS and catB activity delays MHC class II sodium dodecyl sulfate stable dimer formation and impairs Ag degradation. In DCs exposed to tetanus toxoid, IL-10 accordingly reduces the number of MHC class II–peptide complexes accessible to tetanus toxoid–specific T cell receptors, as analyzed by measuring T cell receptor downregulation in Ag-specific T cell clones. Thus, the control of protease activity by pro- and antiinflammatory cytokines is an essential feature of the Ag presentation properties of DCs. PMID:11304549

  2. Macrophage cell lines derived from major histocompatibility complex II-negative mice

    NASA Technical Reports Server (NTRS)

    Beharka, A. A.; Armstrong, J. W.; Chapes, S. K.; Spooner, B. S. (Principal Investigator)

    1998-01-01

    Two bone-marrow-derived macrophage cell lines, C2D and C2Dt, were isolated from major histocompatibility class II negative knock-out mice. The C2D cell line was stabilized by continuous culture in colony-stimulating factor-1 and the C2Dt cell line was transformed with SV40 virus large T antigen. These cells exhibited phenotypic properties of macrophages including morphology and expression of Mac 1 and Mac 2 cell surface molecules. These cells also had comparable growth to the bone-marrow-derived macrophage cell line B6MP102. These new cell lines were not spontaneously cytotoxic and were only capable of modest killing of F5b tumor cells when stimulated with LPS and interferon-gamma, but not when stimulated with LPS alone or with staphylococcal exotoxin. C2D and C2Dt cells phagocytosed labeled Staphylococcus aureus similarly to B6MP102 cells but less well than C2D peritoneal macrophages. These cell lines secreted interleukin-6, but not tumor necrosis factor or nitric oxide in response to LPS or staphlococcal enterotoxins A or B C2D(t) cells were tumorigenic in C2D and C57BL/6J mice but C2D cells were not. These data suggest that macrophage cell lines can be established from bone marrow cells of major histocompatibility complex II-negative mice.

  3. Porcine major histocompatibility complex (MHC) class I molecules and analysis of their peptide-binding specificities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In all vertebrate animals, CD8+ cytotoxic T lymphocytes (CTLs) are controlled by major histocompatibility complex class I (MHC-I) molecules, which are highly polymorphic peptide receptors selecting and presenting endogenously derived epitopes to circulating cytotoxic lymphocytes (CTLs). The polymorp...

  4. Inhibition by chloroquine of the class II major histocompatibility complex-restricted presentation of endogenous antigens varies according to the cellular origin of the antigen-presenting cells, the nature of the T-cell epitope, and the responding T cell.

    PubMed Central

    Lombard-Platlet, S; Bertolino, P; Deng, H; Gerlier, D; Rabourdin-Combe, C

    1993-01-01

    Chloroquine treatment of antigen-presenting cells (APC) was explored as a tool to investigate the processing pathway for major histocompatibility complex (MHC) class II-restricted presentation of the endogenous secreted hen egg lysozyme (HEL) and transmembrane measles virus haemagglutinin (HA). A 72-hr pretreatment of the APC with 25 microM chloroquine blocked the presentation of the HEL(52-61) T-cell epitope generated from endogenous HEL to the I-Ak-restricted 3A9 T-cell hybridoma by MHC class II-transfected L cells expressing the invariant chain (Ii). The presentation of exogenously added HEL peptides was not affected. Under the same conditions, no inhibition of the presentation of HEL(106-116) to the I-Ed-restricted G28 high-avidity T-cell hybridoma, nor of HA when synthesized by L cells, was observed. When B-lymphoid APC were used, inhibition was observed in every case with a low number of B APC pretreated for 48 hr with chloroquine prior to the T-cell stimulation test. Moreover, addition of chloroquine to untreated B APC during the T-cell stimulation assay was sufficient to inhibit completely the presentation of HEL(106-116) to the B10.D24.42 low avidity T-cell hybridoma. Altogether these studies suggest that an apparent resistance of endogenous Ag presentation to chloroquine inhibition may not necessarily indicate the existence of a non-endosomal pathway but may be due to the nature of the T-cell epitope, to the use of 'non-professional' APC such as L cells, to the use of T cells of high avidity, and to high amounts of pre-existing MHC class II-peptide complexes expressed by the APC. We demonstrate here that, at least in conventional APC such as B cells, class II-restricted presentation of both endogenous secreted HEL and transmembrane HA involves an endosomal pathway. PMID:7508420

  5. Characterisation of Major Histocompatibility Complex Class I in the Australian Cane Toad, Rhinella marina

    PubMed Central

    Lillie, Mette; Shine, Richard; Belov, Katherine

    2014-01-01

    The Major Histocompatibility Complex (MHC) class I is a highly variable gene family that encodes cell-surface receptors vital for recognition of intracellular pathogens and initiation of immune responses. The MHC class I has yet to be characterised in bufonid toads (Order: Anura; Suborder: Neobatrachia; Family: Bufonidae), a large and diverse family of anurans. Here we describe the characterisation of a classical MHC class I gene in the Australian cane toad, Rhinella marina. From 25 individuals sampled from the Australian population, we found only 3 alleles at this classical class I locus. We also found large number of class I alpha 1 alleles, implying an expansion of class I loci in this species. The low classical class I genetic diversity is likely the result of repeated bottleneck events, which arose as a result of the cane toad's complex history of introductions as a biocontrol agent and its subsequent invasion across Australia. PMID:25093458

  6. Human Herpesvirus 7 U21 Tetramerizes To Associate with Class I Major Histocompatibility Complex Molecules

    PubMed Central

    May, Nathan A.; Wang, Qiuhong; Balbo, Andrea; Konrad, Sheryl L.; Buchli, Rico; Hildebrand, William H.; Schuck, Peter

    2014-01-01

    ABSTRACT The U21 gene product from human herpesvirus 7 binds to and redirects class I major histocompatibility complex (MHC) molecules to a lysosomal compartment. The molecular mechanism by which U21 reroutes class I MHC molecules to lysosomes is not known. Here, we have reconstituted the interaction between purified soluble U21 and class I MHC molecules, suggesting that U21 does not require additional cellular proteins to interact with class I MHC molecules. Our results demonstrate that U21, itself predicted to contain an MHC class I-like protein fold, interacts tightly with class I MHC molecules as a tetramer, in a 4:2 stoichiometry. These observations have helped to elucidate a refined model describing the mechanism by which U21 escorts class I MHC molecules to the lysosomal compartment. IMPORTANCE In this report, we show that the human herpesvirus 7 (HHV-7) immunoevasin U21, itself a class I MHC-like protein, binds with high affinity to class I MHC molecules as a tetramer and escorts them to lysosomes, where they are degraded. While many class I MHC-like molecules have been described in detail, this unusual viral class I-like protein functions as a tetramer, associating with class I MHC molecules in a 4:2 ratio, illuminating a functional significance of homooligomerization of a class I MHC-like protein. PMID:24390327

  7. Molecular identification, polymorphism, and expression analysis of major histocompatibility complex class IIA and B genes of turbot (Scophthalmus maximus).

    PubMed

    Zhang, Yu-Xi; Chen, Song-Lin

    2006-01-01

    Major histocompatibility complex (MHC) class II has a central role in the adaptive immune system by presenting foreign peptides to the T-cell receptor. The full lengths of MHC class II A and B cDNA were cloned from turbot by homology cloning and rapid amplification of cDNA ends polymerase chain reaction (RACE PCR), and genomic organization, molecular polymorphism, and expression of turbot class IIB gene were examined to study the function of class IIB gene in fish. The deduced amino acid sequence of turbot class II A (GenBank accession no.DQ001730) and turbot class IIB (GenBank accession no. DQ094170) had 69.8%, 67.6%, 65.5%, 59.2%, 54.5%, 52.8%, 46.2%, 46.6%, 28.3%, 28.5%, 22.2% identity and 71.5%, 70.7%, 67.1%, 68.4%, 46.7%, 53.5%, 46.7%, 50.0%, 25.2%, 29.2%, 27.6% identity with those of Japanese flounder, striped sea bass, red sea bream, cichlid, rainbow trout, Atlantic salmon, carp, zebrafish, nurse shark, mouse and human, respectively. Eleven class IIB alleles were identified from three turbot individuals. The amino acid sequence of turbot class IIB designated as Scma-DAB*0101 had 86.9%, 88.6%, 88.6%, 89.4%, 87.8%, 86.9%, 84.1%, 86.5%, 87.3%, 77.1%, and 86.9% identity with those of turbot class IIB 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 (Scma-DAB*0201- Scma-DAB*1201), respectively. Six different class IIB alleles observed in a single individual may infer the existence of three loci at least. Semiquantitative reverse transcriptase PCR (RT-PCR) demonstrated that turbot class IIA and B were ubiquitously expressed in normal tissues. Challenge of turbot with pathogenic bacteria, Vibrio anguillarum, resulted in a significant decrease in the expression of MHC class IIB mRNA from 24 h to 48 h after infection in liver and head kidney, and a significant decrease from 24 h to 72 h after infection in spleen, followed by an increase after 96 h, respectively.

  8. Properties and Applications of Single-Chain Major Histocompatibility Complex Class I Molecules

    PubMed Central

    Kotsiou, Eleni; Brzostek, Joanna

    2011-01-01

    Abstract Stable major histocompatibility complex (MHC) class I molecules at the cell surface consist of three separate, noncovalently associated components: the class I heavy chain, the β2-microglobulin light chain, and a presented peptide. These three components are assembled inside cells via complex pathways involving many other proteins that have been studied extensively. Correct formation of disulfide bonds in the endoplasmic reticulum is central to this process of MHC class I assembly. For a single specific peptide to be presented at the cell surface for possible immune recognition, between hundreds and thousands of peptide-containing precursor polypeptides are required, so the overall process is relatively inefficient. To increase the efficiency of antigen presentation by MHC class I molecules, and for possible therapeutic purposes, single-chain molecules have been developed in which the three, normally separate components have been joined together via flexible linker sequences in a single polypeptide chain. Remarkably, these single-chain MHC class I molecules fold up correctly, as judged by functional recognition by cells of the immune system, and more recently by X-ray crystallographic structural data. This review focuses on the interesting properties and potential of this new type of engineered MHC class I molecule. Antioxid. Redox Signal. 15, 645–655. PMID:21126187

  9. Evolutionary instability of the major histocompatibility complex class I loci in New World primates

    PubMed Central

    Cadavid, Luis F.; Shufflebotham, Clare; Ruiz, Francisco J.; Yeager, Meredith; Hughes, Austin L.; Watkins, David I.

    1997-01-01

    Homologues of the human major histocompatibility complex (MHC) HLA-A, -B, -E, -F, and -G loci are present in all the Catarrhini (Old World primates, apes, and humans), and some of their allelic lineages have survived several speciation events. Analysis of 26 MHC class I cDNAs from seven different genera of New World primates revealed that the Callitrichinae (tamarins and marmosets) are an exception to these rules of MHC stability. In gene trees of primate MHC class I genes, sequences from the Callitrichinae cluster in a genus-specific fashion, whereas in the other genera of New World primates, as in the Catarrhini, they cluster in a transgeneric way. The genus-specific clustering of the Callitrichinae cDNAs indicates that there is no orthology between MHC class I loci in genera of this phyletic group. Additionally, the Callitrichinae genera exhibit limited variability of their MHC class I genes, in contrast to the high variability displayed by all other primates. Each Callitrichinae genus, therefore, expresses its own set of MHC class I genes, suggesting that an unusually high rate of turnover of loci occurs in this subfamily. The limited variability of MHC class I genes in the Callitrichinae is likely the result of the recent origin of these loci. PMID:9405648

  10. Mechanism of induction of class I major histocompatibility antigen expression by murine leukemia virus.

    PubMed

    Faller, D V; Wilson, L D; Flyer, D C

    1988-03-01

    Alterations in expression of major histocompatibility complex (MHC) antigens on tumor cells clearly correlate with the tumorgenicity and metastatic potential of those cells. These changes in the biological behavior of the tumor cells are presumably secondary to resulting changes in their susceptibility to immune recognition and destruction. Murine leukemia viruses (MuLV) exert regulatory effects on class I genes of the MHC locus. MuLV infection results in substantial increases in cell surface expression of all three class I MHC antigens. These viral effects on MHC antigen expression profoundly influence immune-mediated interaction with the infected cells, as assessed by cytotoxic T lymphocyte recognition and killing. Control of class I MHC and beta-2 microglobulin genes by MuLV takes place via a trans-acting molecular mechanism. MuLV controls expression of widely separated endogenous cellular MHC genes, transfected xenogeneic class I MHC genes, and unintegrated chimeric genes consisting of fragments of class I MHC genes linked to a bacterial reporter gene. These findings indicate that MuLV exerts its effects on MHC expression via a trans mechanism. The MuLV-responsive sequences on the MHC genes appear to lie within 1.2 kilobases upstream of the initiation codon for those genes.

  11. Class I major histocompatibility proteins are an essential component of the simian virus 40 receptor.

    PubMed

    Breau, W C; Atwood, W J; Norkin, L C

    1992-04-01

    The class I molecules encoded by the major histocompatibility complex (MHC) present endogenously synthesized antigenic peptide fragments to cytotoxic T lymphocytes. We show here that these proteins are an essential component of the cell surface receptor for simian virus 40 (SV40). First, SV40 binding to cells can be blocked by two monoclonal antibodies against class I human lymphocyte antigen (HLA) proteins but not by monoclonal antibodies specific for other cell surface proteins. Second, SV40 does not bind to cells of two different human lymphoblastoid cell lines which do not express surface class I MHC proteins because of genetic defects in the beta 2-microglobulin gene in one line and in the HLA complex in the other. Transfection of these cell lines with cloned genes for beta 2-microglobulin and HLA-B8, respectively, restored expression of their surface class I MHC proteins and resulted in concomitant SV40 binding. Finally, SV40 binds to purified HLA proteins in vitro and selectively binds to class I MHC proteins in a cell surface extract.

  12. Selection, trans-species polymorphism, and locus identification of major histocompatibility complex class IIβ alleles of New World ranid frogs

    USGS Publications Warehouse

    Kiemnec-Tyburczy, Karen M.; Richmond, Jonathan Q.; Savage, Anna E.; Zamudio, Kelly R.

    2010-01-01

    Genes encoded by the major histocompatibility complex (MHC) play key roles in the vertebrate immune system. However, our understanding of the evolutionary processes and underlying genetic mechanisms shaping these genes is limited in many taxa, including amphibians, a group currently impacted by emerging infectious diseases. To further elucidate the evolution of the MHC in frogs (anurans) and develop tools for population genetics, we surveyed allelic diversity of the MHC class II ??1 domain in both genomic and complementary DNA of seven New World species in the genus Rana (Lithobates). To assign locus affiliation to our alleles, we used a "gene walking" technique to obtain intron 2 sequences that flanked MHC class II?? exon 2. Two distinct intron sequences were recovered, suggesting the presence of at least two class II?? loci in Rana. We designed a primer pair that successfully amplified an orthologous locus from all seven Rana species. In total, we recovered 13 alleles and documented trans-species polymorphism for four of the alleles. We also found quantitative evidence of selection acting on amino acid residues that are putatively involved in peptide binding and structural stability of the ??1 domain of anurans. Our results indicated that primer mismatch can result in polymerase chain reaction (PCR) bias, which influences the number of alleles that are recovered. Using a single locus may minimize PCR bias caused by primer mismatch, and the gene walking technique was an effective approach for generating single-copy orthologous markers necessary for future studies of MHC allelic variation in natural amphibian populations. ?? 2010 Springer-Verlag.

  13. Identification of 32 major histocompatibility complex class I alleles in African green monkeys.

    PubMed

    Cao, Y; Li, A; Li, L; Yan, X; Fa, Y; Zeng, L; Fan, J; Liu, B; Sun, Z

    2014-09-01

    The African green monkey may be an ideal replacement for the rhesus monkey in biomedical research, but relatively little is known about the genetic background of major histocompatibility complex (MHC) class I molecules. In analysis of 12 African green monkeys, 13 Chae-A and 19 Chae-B alleles were identified. Among these alleles, 12 Chae-A and 9 Chae-B were new lineages. The full amino acid length deduced for Chae-A genes is 365 amino acids, but for Chae-B genes, the lengths are 365, 362, 361, and 359 amino acids, respectively. There were 1-3 Chae-A alleles and 2-5 Chae-B alleles in each animal. In African green monkeys, rhesus monkeys, and cynomolgus monkeys, the MHC-A and MHC-B alleles display trans-species polymorphism, rather than being clustered in a species-specific fashion.

  14. Enhanced Direct Major Histocompatibility Complex Class I Self-Antigen Presentation Induced by Chlamydia Infection

    PubMed Central

    Cram, Erik D.; Simmons, Ryan S.; Palmer, Amy L.; Hildebrand, William H.; Rockey, Daniel D.

    2015-01-01

    The direct major histocompatibility complex (MHC) class I antigen presentation pathway ensures intracellular peptides are displayed at the cellular surface for recognition of infected or transformed cells by CD8+ cytotoxic T lymphocytes. Chlamydia spp. are obligate intracellular bacteria and, as such, should be targeted by CD8+ T cells. It is likely that Chlamydia spp. have evolved mechanisms to avoid the CD8+ killer T cell responses by interfering with MHC class I antigen presentation. Using a model system of self-peptide presentation which allows for posttranslational control of the model protein's stability, we tested the ability of various Chlamydia species to alter direct MHC class I antigen presentation. Infection of the JY lymphoblastoid cell line limited the accumulation of a model host protein and increased presentation of the model-protein-derived peptides. Enhanced self-peptide presentation was detected only when presentation was restricted to defective ribosomal products, or DRiPs, and total MHC class I levels remained unaltered. Skewed antigen presentation was dependent on a bacterial synthesized component, as evidenced by reversal of the observed phenotype upon preventing bacterial transcription, translation, and the inhibition of bacterial lipooligosaccharide synthesis. These data suggest that Chlamydia spp. have evolved to alter the host antigen presentation machinery to favor presentation of defective and rapidly degraded forms of self-antigen, possibly as a mechanism to diminish the presentation of peptides derived from bacterial proteins. PMID:26597986

  15. The molecular chaperone calnexin facilitates folding and assembly of class I histocompatibility molecules.

    PubMed Central

    Vassilakos, A; Cohen-Doyle, M F; Peterson, P A; Jackson, M R; Williams, D B

    1996-01-01

    Calnexin, a membrane protein of the endoplasmic reticulum, is generally thought to function as a molecular chaperone, based on indirect or correlative evidence. To examine calnexin's functions more directly, we reconstituted the assembly of class I histocompatibility molecules in the absence or presence of calnexin in Drosophila melanogaster cells. Calnexin enhanced the assembly of class I heavy chains with beta 2-microglobulin as much as 5-fold. The improved assembly appeared largely due to more efficient folding of heavy chains, as evidenced by increased reactivity with a conformation-sensitive monoclonal antibody and by a reduction in the level of aggregates. Similar findings were obtained in mouse or human cells when the interaction of calnexin with class I heavy chains was prevented by treatment with the oligosaccharide processing inhibitor castanospermine. The ability of calnexin to facilitate castanospermine. The ability of calnexin to facilitate heavy chain folding and to prevent the formation of aggregates provides compelling evidence that calnexin functions as a bona fide molecular chaperone. Images PMID:8612572

  16. Efficient major histocompatibility complex class I presentation of exogenous antigen upon phagocytosis by macrophages.

    PubMed Central

    Kovacsovics-Bankowski, M; Clark, K; Benacerraf, B; Rock, K L

    1993-01-01

    Antigens in extracellular fluids can be processed and presented with major histocompatibility complex (MHC) class I molecules by a subset of antigen presenting cells (APCs). Chicken egg ovalbumin (Ova) linked to beads was presented with MHC class I molecules by these cells up to 10(4)-fold more efficiently than soluble Ova. This enhanced presentation was observed with covalently or noncovalently linked Ova and with beads of different compositions. A key parameter in the activity of these conjugates was the size of the beads. The APC that is responsible for this form of presentation is a macrophage. These cells internalize the antigen constructs through phagocytosis, since cytochalasin B inhibited presentation. Processing of the antigen and association with MHC class I molecules appears to occur intracellularly as presentation was observed under conditions where there was no detectable release of peptides into the extracellular fluids. When injected in vivo in C57BL/6 mice, Ova-beads, but not soluble Ova, primed CD4- CD8+ cytotoxic T lymphocytes (CTLs). Similar results were obtained in BALB/c mice immunized with beta-galactosidase-beads. The implications of these findings for development of nonliving vaccines that stimulate CTL immunity are discussed. PMID:8506338

  17. Isolation and characterization of major histocompatibility complex class IIB genes from the nurse shark.

    PubMed Central

    Bartl, S; Weissman, I L

    1994-01-01

    The major histocompatibility complex (MHC) contains a set of linked genes which encode cell surface proteins involved in the binding of small peptide antigens for their subsequent recognition by T lymphocytes. MHC proteins share structural features and the presence and location of polymorphic residues which play a role in the binding of antigens. In order to compare the structure of these molecules and gain insights into their evolution, we have isolated two MHC class IIB genes from the nurse shark, Ginglymostoma cirratum. Two clones, most probably alleles, encode proteins which differ by 13 amino acids located in the putative antigen-binding cleft. The protein structure and the location of polymorphic residues are similar to their mammalian counterparts. Although these genes appear to encode a typical MHC protein, no T-cell-mediated responses have been demonstrated in cartilaginous fish. The nurse shark represents the most phylogenetically primitive organism in which both class IIA [Kasahara, M., Vazquez, M., Sato, K., McKinney, E.C. & Flajnik, M.F. (1992) Proc. Natl. Acad. Sci USA 89, 6688-6692] and class IIB genes, presumably encoding the alpha/beta heterodimer, have been isolated. Images Fig. 2 PMID:8278377

  18. Genomic organization of duplicated major histocompatibility complex class I regions in Atlantic salmon (Salmo salar)

    PubMed Central

    Lukacs, Morten F; Harstad, Håvard; Grimholt, Unni; Beetz-Sargent, Marianne; Cooper, Glenn A; Reid, Linda; Bakke, Hege G; Phillips, Ruth B; Miller, Kristina M; Davidson, William S; Koop, Ben F

    2007-01-01

    Background We have previously identified associations between major histocompatibility complex (MHC) class I and resistance towards bacterial and viral pathogens in Atlantic salmon. To evaluate if only MHC or also closely linked genes contributed to the observed resistance we ventured into sequencing of the duplicated MHC class I regions of Atlantic salmon. Results Nine BACs covering more than 500 kb of the two duplicated MHC class I regions of Atlantic salmon were sequenced and the gene organizations characterized. Both regions contained the proteasome components PSMB8, PSMB9, PSMB9-like and PSMB10 in addition to the transporter for antigen processing TAP2, as well as genes for KIFC1, ZBTB22, DAXX, TAPBP, BRD2, COL11A2, RXRB and SLC39A7. The IA region contained the recently reported MHC class I Sasa-ULA locus residing approximately 50 kb upstream of the major Sasa-UBA locus. The duplicated class IB region contained an MHC class I locus resembling the rainbow trout UCA locus, but although transcribed it was a pseudogene. No other MHC class I-like genes were detected in the two duplicated regions. Two allelic BACs spanning the UBA locus had 99.2% identity over 125 kb, while the IA region showed 82.5% identity over 136 kb to the IB region. The Atlantic salmon IB region had an insert of 220 kb in comparison to the IA region containing three chitin synthase genes. Conclusion We have characterized the gene organization of more than 500 kb of the two duplicated MHC class I regions in Atlantic salmon. Although Atlantic salmon and rainbow trout are closely related, the gene organization of their IB region has undergone extensive gene rearrangements. The Atlantic salmon has only one class I UCA pseudogene in the IB region while trout contains the four MHC UCA, UDA, UEA and UFA class I loci. The large differences in gene content and most likely function of the salmon and trout class IB region clearly argues that sequencing of salmon will not necessarily provide information

  19. Major histocompatibility complex class I genes of the coelacanth Latimeria chalumnae.

    PubMed

    Betz, U A; Mayer, W E; Klein, J

    1994-11-01

    The coelacanth fish Latimeria chalumnae is the sole surviving species of a phylogenetic lineage that was founded more than 400 million years ago and that has changed morphologically very little since that time. Little is known about the molecular evolution of this "living fossil," considered by some taxonomists to be the closest living relative of tetrapods. Here we describe the isolation and characterization of L. chalumnae major histocompatibility complex (MHC) class I genes. The exon-intron organization of these genes is the same as that of their mammalian counterparts. The genes fall into four families, which we designate Lach-UA through Lach-UD. There are multiple loci in all of the families. Genes of the first two families are transcribed. The Lach-UA family bears the characteristics of functional, polymorphic class I genes; the other three families may be represented by nonclassical genes. All the Lach loci arose by duplication from an ancestral gene after the foundation of the coelacanth lineage. Intergenic variation is highest at positions corresponding to the mammalian peptide-binding region. The closest relatives of the Lach genes among the MHC genes sequenced thus far are those of the amphibian Xenopus.

  20. Trophoblast Major Histocompatibility Complex Class I Expression Is Associated with Immune-Mediated Rejection of Bovine Fetuses Produced by Cloning.

    PubMed

    Rutigliano, Heloisa M; Thomas, Aaron J; Wilhelm, Amanda; Sessions, Benjamin R; Hicks, Brady A; Schlafer, Donald H; White, Kenneth L; Davies, Christopher J

    2016-08-01

    Trophoblast cells from bovine somatic cell nuclear transfer (SCNT) conceptuses express major histocompatibility complex class I (MHC-I) proteins early in gestation, and this may be one cause of the significant first-trimester embryonic mortality observed in these pregnancies. MHC-I homozygous-compatible (n = 9), homozygous-incompatible (n = 8), and heterozygous-incompatible (n = 5) SCNT pregnancies were established. The control group consisted of eight pregnancies produced by artificial insemination. Uterine and placental samples were collected on Day 35 ± 1 of pregnancy, and expression of MHC-I, leukocyte markers, and cytokines were examined by immunohistochemistry. Trophoblast cells from all SCNT pregnancies expressed MHC-I, while trophoblast cells from age-matched control pregnancies were negative for MHC-I expression. Expression of MHC-I antigens by trophoblast cells from SCNT pregnancies was associated with lymphocytic infiltration in the endometrium. Furthermore, MHC-I-incompatible conceptuses, particularly the heterozygous-incompatible ones, induced a more pronounced lymphocytic infiltration than MHC-I-compatible conceptuses. Cells expressing cluster of differentiation (CD) 3, gamma/deltaTCR, and MHC-II were increased in the endometrium of SCNT pregnancies compared to the control group. CD4(+) lymphocytes were increased in MHC-I-incompatible pregnancies compared to MHC-I-compatible and control pregnancies. CD8(+), FOXP3(+), and natural killer cells were increased in MHC-I heterozygous-incompatible SCNT pregnancies compared to homozygous SCNT and control pregnancies.

  1. Cross-linking staphylococcal enterotoxin A bound to major histocompatibility complex class I is required for TNF-alpha secretion

    NASA Technical Reports Server (NTRS)

    Wright, A. D.; Chapes, S. K.

    1999-01-01

    The mechanism of how superantigens function to activate cells has been linked to their ability to bind and cross-link the major histocompatibility complex class II (MHCII) molecule. Cells that lack the MHCII molecule also respond to superantigens, however, with much less efficiency. Therefore, the purpose of this study was to confirm that staphylococcal enterotoxin A (SEA) could bind the MHCI molecule and to test the hypothesis that cross-linking SEA bound to MHCII-deficient macrophages would induce a more robust cytokine response than without cross-linking. We used a capture enzyme-linked immunosorbent assay and an immunprecipitation assay to directly demonstrate that MHCI molecules bind SEA. Directly cross-linking MHCI using monoclonal antibodies or cross-linking bound SEA with an anti-SEA antibody or biotinylated SEA with avidin increased TNF-alpha and IL-6 secretion by MHCII(-/-) macrophages. The induction of a vigorous macrophage cytokine response by SEA/anti-SEA cross-linking of MHCI offers a mechanism to explain how MHCI could play an important role in superantigen-mediated pathogenesis. Copyright 1999 Academic Press.

  2. Trophoblast Major Histocompatibility Complex Class I Expression Is Associated with Immune-Mediated Rejection of Bovine Fetuses Produced by Cloning.

    PubMed

    Rutigliano, Heloisa M; Thomas, Aaron J; Wilhelm, Amanda; Sessions, Benjamin R; Hicks, Brady A; Schlafer, Donald H; White, Kenneth L; Davies, Christopher J

    2016-08-01

    Trophoblast cells from bovine somatic cell nuclear transfer (SCNT) conceptuses express major histocompatibility complex class I (MHC-I) proteins early in gestation, and this may be one cause of the significant first-trimester embryonic mortality observed in these pregnancies. MHC-I homozygous-compatible (n = 9), homozygous-incompatible (n = 8), and heterozygous-incompatible (n = 5) SCNT pregnancies were established. The control group consisted of eight pregnancies produced by artificial insemination. Uterine and placental samples were collected on Day 35 ± 1 of pregnancy, and expression of MHC-I, leukocyte markers, and cytokines were examined by immunohistochemistry. Trophoblast cells from all SCNT pregnancies expressed MHC-I, while trophoblast cells from age-matched control pregnancies were negative for MHC-I expression. Expression of MHC-I antigens by trophoblast cells from SCNT pregnancies was associated with lymphocytic infiltration in the endometrium. Furthermore, MHC-I-incompatible conceptuses, particularly the heterozygous-incompatible ones, induced a more pronounced lymphocytic infiltration than MHC-I-compatible conceptuses. Cells expressing cluster of differentiation (CD) 3, gamma/deltaTCR, and MHC-II were increased in the endometrium of SCNT pregnancies compared to the control group. CD4(+) lymphocytes were increased in MHC-I-incompatible pregnancies compared to MHC-I-compatible and control pregnancies. CD8(+), FOXP3(+), and natural killer cells were increased in MHC-I heterozygous-incompatible SCNT pregnancies compared to homozygous SCNT and control pregnancies. PMID:27385783

  3. [Modified Class II tunnel preparation].

    PubMed

    Rimondini, L; Baroni, C

    1991-05-15

    Tunnel preparations for restoration of Class II carious lesions in primary molars preserve the marginal ridge and minimize sacrifice of healthy tooth substructure. Materials with improved bonding to tooth structure and increase potential for fluoride release allow Class II restorations without "extension for prevention". PMID:1864420

  4. Contrasting evolutionary histories of MHC class I and class II loci in grouse—Effects of selection and gene conversion

    USGS Publications Warehouse

    Minias, Piotr; Bateson, Zachary W; Whittingham, Linda A; Johnson, Jeff A.; Oyler-McCance, Sara J.; Dunn, Peter O

    2016-01-01

    Genes of the major histocompatibility complex (MHC) encode receptor molecules that are responsible for recognition of intracellular and extracellular pathogens (class I and class II genes, respectively) in vertebrates. Given the different roles of class I and II MHC genes, one might expect the strength of selection to differ between these two classes. Different selective pressures may also promote different rates of gene conversion at each class. Despite these predictions, surprisingly few studies have looked at differences between class I and II genes in terms of both selection and gene conversion. Here, we investigated the molecular evolution of MHC class I and II genes in five closely related species of prairie grouse (Centrocercus and Tympanuchus) that possess one class I and two class II loci. We found striking differences in the strength of balancing selection acting on MHC class I versus class II genes. More than half of the putative antigen-binding sites (ABS) of class II were under positive or episodic diversifying selection, compared with only 10% at class I. We also found that gene conversion had a stronger role in shaping the evolution of MHC class II than class I. Overall, the combination of strong positive (balancing) selection and frequent gene conversion has maintained higher diversity of MHC class II than class I in prairie grouse. This is one of the first studies clearly demonstrating that macroevolutionary mechanisms can act differently on genes involved in the immune response against intracellular and extracellular pathogens.

  5. Polarisation of Major Histocompatibility Complex II Host Genotype with Pathogenesis of European Brown Hare Syndrome Virus

    PubMed Central

    Iacovakis, Christos; Mamuris, Zissis; Moutou, Katerina A.; Touloudi, Antonia; Hammer, Anne Sofie; Valiakos, George; Giannoulis, Themis; Stamatis, Costas; Spyrou, Vassiliki; Athanasiou, Labrini V.; Kantere, Maria; Asferg, Tommy; Giannakopoulos, Alexios; Salomonsen, Charlotte M.; Bogdanos, Dimitrios; Birtsas, Periklis; Petrovska, Liljana; Hannant, Duncan; Billinis, Charalambos

    2013-01-01

    and MHC class II genotype within the European brown hare in Denmark. PMID:24069299

  6. Covalent assembly of a soluble T cell receptor-peptide-major histocompatibility class I complex.

    PubMed Central

    Grégoire, C; Lin, S Y; Mazza, G; Rebai, N; Luescher, I F; Malissen, B

    1996-01-01

    We used stepwise photochemical cross-linking for specifically assembling soluble and covalent complexes made of a T-cell antigen receptor (TCR) and a class I molecule of the major histocompatibility complex (MHC) bound to an antigenic peptide. For that purpose, we have produced in myeloma cells a single-chain Fv construct of a TCR specific for a photoreactive H-2Kd-peptide complex. Photochemical cross-linking of this TCR single-chain Fv with a soluble form of the photoreactive H-2Kd-peptide ligand resulted in the formation of a ternary covalent complex. We have characterized the soluble ternary complex and showed that it reacted with antibodies specific for epitopes located either on the native TCR or on the Kd molecules. By preventing the fast dissociation kinetics observed with most T cell receptors, this approach provides a means of preparing soluble TCR-peptide-MHC complexes on large-scale levels. Images Fig. 3 Fig. 4 PMID:8692966

  7. Diacylglycerol kinase α regulates tubular recycling endosome biogenesis and major histocompatibility complex class I recycling.

    PubMed

    Xie, Shuwei; Naslavsky, Naava; Caplan, Steve

    2014-11-14

    Major histocompatibility complex class I (MHC I) presents intracellular-derived peptides to cytotoxic T lymphocytes and its subcellular itinerary is important in regulating the immune response. While a number of diacylglycerol kinase isoforms have been implicated in clathrin-dependent internalization, MHC I lacks the typical motifs known to mediate clathrin-dependent endocytosis. Here we show that depletion of diacylglycerol kinase α (DGKα), a kinase devoid of a clathrin-dependent adaptor protein complex 2 binding site, caused a delay in MHC I recycling to the plasma membrane without affecting the rate of MHC I internalization. We demonstrate that DGKα knock-down causes accumulation of intracellular and surface MHC I, resulting from decreased degradation. Furthermore, we provide evidence that DGKα is required for the generation of phosphatidic acid required for tubular recycling endosome (TRE) biogenesis. Moreover, we show that DGKα forms a complex with the TRE hub protein, MICAL-L1. Given that MICAL-L1 and the F-BAR-containing membrane-tubulating protein Syndapin2 associate selectively with phosphatidic acid, we propose a positive feedback loop in which DGKα generates phosphatidic acid to drive its own recruitment to TRE via its interaction with MICAL-L1. Our data support a novel role for the involvement of DGKα in TRE biogenesis and MHC I recycling.

  8. Localization of eight additional genes in the human major histocompatibility complex, including the gene encoding the casein kinase II {beta} subunit (CSNK2B)

    SciTech Connect

    Albertella, M.R.; Jones, H.; Thomson, W.

    1996-09-01

    A wide range of autoimmune and other diseases are known to be associated with the major histocompatibility complex. Many of these diseases are linked to the genes encoding the polymorphic histocompatibility complex. Many of these diseases are linked to the genes encoding the polymorphic histocompatibility antigens in the class I and class II regions, but some appear to be more strongly associated with genes in the central 1100-kb class III region, making it important to characterize this region fully for the presence of novel genes. An {approximately}220-kb segment of DNA in the class III region separating the Hsp70 (HSPA1L) and BAT1 (D6S8IE) genes, which was previously known to contain 14 genes. Genomic DNA fragments spanning the gaps between the known genes were used as probes to isolate cDNAs corresponding to five new genes within this region. Evidence from Northern blot analysis and exon trapping experiments that suggested the presence of at least two more new genes was also obtained. Partial cDNA and complete exonic genomic sequencing of one of the new genes has identified it as the casein kinase II{beta} subunit (CSNK2B). Two of the other novel genes lie within a region syntenic to that implicated in susceptibility to experimental allergic orchitis in the mouse, an autoimmune disease of the testis, and represent additional candidates for the Orch-1 locus associated with this disease. In addition, characterization of the 13-kb intergenic gap separating the RD (D6545) and G11 (D6S60E) genes has revealed the presence of a gene encoding a 1246-amino-acid polypeptide that shows significant sequence similarity to the yeast anti-viral Ski2p gene product. 49 refs., 8 figs.

  9. Defective major histocompatibility complex class I expression on lymphoid cells in autoimmunity.

    PubMed Central

    Fu, Y; Nathan, D M; Li, F; Li, X; Faustman, D L

    1993-01-01

    Lymphocytes from patients with insulin-dependent diabetes mellitus (IDDM), a chronic autoimmune disease, have recently been shown to have decreased surface expression of MHC class I antigens. Since IDDM and other autoimmune diseases share a strong genetic association with MHC class II genes, which may in turn be linked to genes that affect MHC class I expression, we studied other autoimmune diseases to determine whether MHC class I expression is abnormal. Fresh PBLs were isolated from patients with IDDM, Hashimoto's thyroiditis, Graves' disease, systemic lupus erythematosis, rheumatoid arthritis, and Sjogren's syndrome. Nondiabetic and non-insulin-dependent diabetes mellitus patients served as controls. MHC class I expression was measured with a conformationally dependent monoclonal antibody, W6/32. Freshly prepared PBLs from the autoimmune diseases studied and the corresponding fresh EBV-transformed B cell lines had decreased MHC class I expression compared with PBLs from normal volunteers and non-insulin-dependent (nonautoimmune) diabetic patients. Only 3 of more than 180 donors without IDDM or other clinically recognized autoimmune disease had persistently decreased MHC class I expression; one patient was treated with immunosuppressive drugs, and subsequent screening of the other two patients revealed high titers of autoantibodies, revealing clinically occult autoimmunity. Patients with nonautoimmune inflammation (osteomyelitis or tuberculosis) had normal MHC class I expression. Autoimmune diseases are characterized by decreased expression of MHC class I on lymphocytes. MHC class I expression may be necessary for self-tolerance, and abnormalities in such expression may lead to autoimmunity. PMID:8486790

  10. Characterization of anti-channel catfish MHC class II monoclonal antibodies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study characterizes four monoclonal antibodies (mAb) developed against the major histocompatibility complex (MHC) class II beta chain of the channel catfish, Ictalurus punctatus. Immunoprecipitations using catfish clonal B cells revealed that each of these mAbs immunoselected proteins of appro...

  11. Dynamics of Major Histocompatibility Complex Class I Association with the Human Peptide-loading Complex*

    PubMed Central

    Panter, Michaela S.; Jain, Ankur; Leonhardt, Ralf M.; Ha, Taekjip; Cresswell, Peter

    2012-01-01

    Although the human peptide-loading complex (PLC) is required for optimal major histocompatibility complex class I (MHC I) antigen presentation, its composition is still incompletely understood. The ratio of the transporter associated with antigen processing (TAP) and MHC I to tapasin, which is responsible for MHC I recruitment and peptide binding optimization, is particularly critical for modeling of the PLC. Here, we characterized the stoichiometry of the human PLC using both biophysical and biochemical approaches. By means of single-molecule pulldown (SiMPull), we determined a TAP/tapasin ratio of 1:2, consistent with previous studies of insect-cell microsomes, rat-human chimeric cells, and HeLa cells expressing truncated TAP subunits. We also report that the tapasin/MHC I ratio varies, with the PLC population comprising both 2:1 and 2:2 complexes, based on mutational and co-precipitation studies. The MHC I-saturated PLC may be particularly prevalent among peptide-selective alleles, such as HLA-C4. Additionally, MHC I association with the PLC increases when its peptide supply is reduced by inhibiting the proteasome or by blocking TAP-mediated peptide transport using viral inhibitors. Taken together, our results indicate that the composition of the human PLC varies under normal conditions and dynamically adapts to alterations in peptide supply that may arise during viral infection. These findings improve our understanding of the quality control of MHC I peptide loading and may aid the structural and functional modeling of the human PLC. PMID:22829594

  12. Identification of the class I genes of the mouse major histocompatibility complex by DNA-mediated gene transfer.

    PubMed

    Goodenow, R S; McMillan, M; Nicolson, M; Sher, B T; Eakle, K; Davidson, N; Hood, L

    1982-11-18

    DNA-mediated gene transfer was used to identify cloned class I genes from the major histocompatibility complex of the BALB/c mouse. Three genes encoding the transplantation antigens H-2 Kd, Dd and Ld were identified as well as genes encoding the Qa-2,3 and two TL differentiation antigens. As many as 10 putative novel class I genes were detected by the association of their gene products with beta 2-microglobulin. Alloantiserum prepared to one of the novel antigens was used to demonstrate the expression of the previously undetected antigen on spleen cells of various inbred, congeneic, and recombinant congeneic strains of mice. PMID:6815535

  13. Features of target cell lysis by class I and class II MHC restricted cytolytic T lymphocytes

    SciTech Connect

    Maimone, M.M.; Morrison, L.A.; Braciale, V.L.; Braciale, T.J.

    1986-12-01

    The lytic activity of influenza virus-specific muvine cytolytic T lymphocyte (CTL) clones that are restricted by either H-2K/D (class I) or H-2I (class II) major histocompatibility (MHC) locus products was compared on an influenza virus-infected target cell expressing both K/D and I locus products. With the use of two in vitro measurements of cytotoxicity, conventional /sup 51/Cr release, and detergent-releasable radiolabeled DNA (as a measure of nuclear disintegration in the early post-lethal hit period), the authors found no difference between class I and class II MHC-restricted CTL in the kinetics of target cell destruction. In addition, class II MHC-restricted antiviral CTL failed to show any lysis of radiolabeled bystander cells. Killing of labeled specific targets by these class II MHC-restricted CTL was also efficiently inhibited by unlabeled specific competitor cells in a cold target inhibition assay. In sum, these data suggest that class I and class II MHC-restricted CTL mediate target cell destruction by an essentially similar direct mechanism.

  14. Blocking MHC class II on human endothelium mitigates acute rejection

    PubMed Central

    Abrahimi, Parwiz; Qin, Lingfeng; Chang, William G.; Bothwell, Alfred L.M.; Tellides, George; Saltzman, W. Mark; Pober, Jordan S.

    2016-01-01

    Acute allograft rejection is mediated by host CD8+ cytotoxic T lymphocytes (CTL) targeting graft class I major histocompatibility complex (MHC) molecules. In experimental rodent models, rejection requires differentiation of naive CD8+ T cells into alloreactive CTL within secondary lymphoid organs, whereas in humans, CTL may alternatively develop within the graft from circulating CD8+ effector memory T cells (TEM) that recognize class I MHC molecules on graft endothelial cells (EC). This latter pathway is poorly understood. Here, we show that host CD4+ TEM, activated by EC class II MHC molecules, provide critical help for this process. First, blocking HLA-DR on EC lining human artery grafts in immunodeficient mice reduces CD8+ CTL development within and acute rejection of the artery by adoptively transferred allogeneic human lymphocytes. Second, siRNA knockdown or CRISPR/Cas9 ablation of class II MHC molecules on EC prevents CD4+ TEM from helping CD8+ TEM to develop into CTL in vitro. Finally, implanted synthetic microvessels, formed from CRISPR/Cas9-modified EC lacking class II MHC molecules, are significantly protected from CD8+ T cell–mediated destruction in vivo. We conclude that human CD8+ TEM–mediated rejection targeting graft EC class I MHC molecules requires help from CD4+ TEM cells activated by recognition of class II MHC molecules. PMID:26900601

  15. Endothelial activation by hydrogen peroxide. Selective increases of intercellular adhesion molecule-1 and major histocompatibility complex class I.

    PubMed Central

    Bradley, J. R.; Johnson, D. R.; Pober, J. S.

    1993-01-01

    Products of activated leukocytes may alter vascular endothelial cell (EC) function. For example, ECs respond to leukocyte-derived cytokines, such as tumor necrosis factor (TNF) or interleukin-1, by reversibly altering levels of expression of specific gene products that promote inflammation. In contrast, hydrogen peroxide, a product of TNF-activated neutrophils, can produce irreversible EC injury and death. In this study, we have investigated the effects of subinjurious concentrations of hydrogen peroxide on EC inflammatory functions. Treatment with 50 to 100 mumol/L hydrogen peroxide selectively increases surface expression of intercellular adhesion molecule-1 and major histocompatibility complex class I, but not endothelial leukocyte adhesion molecule-1 (also known as E-selectin), vascular cell adhesion molecule-1, or gp96, a constitutively expressed EC surface protein. Increased major histocompatibility complex class I and intercellular adhesion molecule-1 surface expression is associated with specifically increased messenger RNA levels, suggesting selective endothelial gene activation. Hydrogen peroxide does not activate the transcription factor Nuclear Factor kappa B, an important mediator of TNF-induced gene expression. Co-treatment with hydrogen peroxide inhibits TNF-induced gene expression at 4 hours, an effect which can be attributed to reversible inhibition of TNF binding to EC surface receptors. Hydrogen peroxide also antagonizes the actions of interleukin-1. At 24 hours, TNF and hydrogen peroxide produce, at most, additive increases in intercellular adhesion molecule-1 and major histocompatibility complex class I. These results suggest that subinjurious concentrations of hydrogen peroxide can activate endothelium and that the effects of hydrogen peroxide on ECs differ from those of inflammatory cytokines. Images Figure 3 Figure 4 Figure 5 PMID:8098585

  16. Reassociation with beta 2-microglobulin is necessary for Db class I major histocompatibility complex binding of an exogenous influenza peptide.

    PubMed Central

    Rock, K L; Gamble, S; Rothstein, L; Benacerraf, B

    1991-01-01

    A synthetic peptide corresponding to residues 365-380 of the influenza nucleoprotein (NP365-380) has been previously shown to associate with class I major histocompatibility complex-encoded molecules and to stimulate cytotoxic T lymphocytes [Townsend, A. R. M., Rothbard, J., Gotch, F. M., Bahadur, G., Wraith, D. & McMichael, A. J. (1986) Cell 44, 959-968]. We find that intact Db class I heterodimers on the cell surface are unreceptive to binding this antigen. However, NP365-380 readily associates with Db molecules on the plasma membrane in the presence of exogenous beta 2-microglobulin. In addition, there is a second pathway through which this peptide associates with class I molecules that requires energy and de novo protein synthesis. These findings have implications for maintaining the immunological identity of cells and for the use of peptides as vaccines for priming cytolytic T-cell immunity. Images PMID:1986378

  17. HLA class II genes: typing by DNA analysis.

    PubMed

    Bidwell, J L; Bidwell, E A; Bradley, B A

    1990-04-01

    A detailed understanding of the structure and function of the human major histocompatibility complex (MHC) has ensued from studies by molecular biologist during the last decade. Virtually all of the HLA genes have now been cloned, and the nucleotide sequences of their different allelic forms have been determined. Typing for these HLA alleles is a fundamental prerequisite for tissue matching in allogeneic organ transplantation. Until very recently, typing procedures have been dominated by serological and cellular methods. The availability of cloned DNA from HLA genes has now permitted the technique of restriction fragment length polymorphism (RFLP) analysis to be applied, with remarkable success and advantage, to phenotyping of both HLA Class I and Class II determinants. For the HLA Class II genes DR and DQ, a simple two-stage RFLP analysis permits the accurate identification of all specificities defined by serology, and of many which are defined by cellular typing. At the present time, however, RFLP typing of HLA Class I genes is not as practicable or as informative as that for HLA Class II genes. The present clinical applications of HLA-DR and DQ RFLP typing are predominantly in phenotyping of living donors, including selection of HLA-matched volunteer bone marrow donors, in allograft survival studies, and in studies of HLA Class II-associated diseases. However, the time taken to perform RFLP analysis precludes its use for the typing of cadaveric kidney donors. Nucleotide sequence data for the alleles of HLA Class II genes have now permitted the development of allele-specific oligonucleotide (ASO) typing, a second category of DNA analysis. This has been greatly facilitated by the ability to amplify specific HLA Class II DNA 'target' sequences using the polymerase chain reaction (PCR) technique. The accuracy of DNA typing techniques should ensure that this methodology will eventually replace conventional HLA phenotyping.

  18. Expression of bovine non-classical major histocompatibility complex class 1 proteins in mouse P815 and human K562 cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Major histocompatibility complex class I (MHC-I) proteins can be expressed as cell surface or secreted proteins. To investigate whether bovine non-classical MHC-I proteins are expressed as cell surface or secreted proteins, and to assess the reactivity pattern of monoclonal antibodies with non-class...

  19. Rheumatoid Rescue of Misfolded Cellular Proteins by MHC Class II Molecules: A New Hypothesis for Autoimmune Diseases.

    PubMed

    Arase, Hisashi

    2016-01-01

    Misfolded proteins localized in the endoplasmic reticulum are degraded promptly and thus are not transported outside cells. However, misfolded proteins in the endoplasmic reticulum are rescued from protein degradation upon association with major histocompatibility complex (MHC) class II molecules and are transported to the cell surface by MHC class II molecules without being processed to peptides. Studies on the misfolded proteins rescued by MHC class II molecules have revealed that misfolded proteins associated with MHC class II molecules are specific targets for autoantibodies produced in autoimmune diseases. Furthermore, a strong correlation has been observed between autoantibody binding to misfolded proteins associated with MHC class II molecules and the autoimmune disease susceptibility conferred by each MHC class II allele. These new insights into MHC class II molecules suggest that misfolded proteins rescued from protein degradation by MHC class II molecules are recognized as "neo-self" antigens by immune system and are involved in autoimmune diseases as autoantibody targets.

  20. Major histocompatibility complex class I expression on neurons in subacute sclerosing panencephalitis and experimental subacute measles encephalitis

    SciTech Connect

    Gogate, N.; Yamabe, Toshio; Verma, L.; Dhib-Jalbut, S.

    1996-04-01

    Lack of major histocompatibility class I antigens on neurons has been implicated as a possible mechanism for viral persistence in the brain since these antigens are required for cytotoxic T-lymphocyte recognition of infected cells. In subacute sclerosing panencephalitis (SSPE), measles virus (MV) persists in neurons, resulting in a fatal chronic infection. MHC class I mRNA expression was examined in formalin-fixed brain tissue from 6 SSPE patients by in situ hybridization. In addition MHC class I protein expression in MV-infected neurons was examined in experimental Subacute Measles Encephalitis (SME) by double immunohistochemistry. MHC class I mRNA expression was found to be upregulated in SSPE tissues studied, and in 5 out of 6 cases the expression was definitively seen on neurons. The percentage of neurons expressing MHC class I mRNA ranged between 20 to 84% in infected areas. There was no correlation between the degree of infection and expression of MHC class I molecules on neurons. Importantly, the number of neurons co-expressing MHC class I and MV antigens was markedly low, varying between 2 to 8%. Similar results were obtained in SME where 20 to 30% of the neurons expressed MHC class I but < 8% co-expressed MHC class I and MV antigens. Perivascular infiltrating cells in the infected regions in SME expressed IFN{gamma} immunoreactivity. The results suggest that MV may not be directly involved in the induction of MHC class I on neurons and that cytokines such as IFN{gamma} may play an important role. Furthermore, the paucity of neurons co-expressing MHC class I and MV antigens in SSPE and SME suggests that such cells are either rapidly cleared by cytotoxic T lymphocytes (CTL), or, alternatively, lack of co-expression of MHC class I on MV infected neurons favors MV persistence in these cells by escaping CTL recognition. 33 refs., 3 figs., 3 tabs.

  1. Failure of expression of class I major histocompatibility antigens to alter tumor immunogenicity of a spontaneous murine carcinoma.

    PubMed

    Carlow, D A; Kerbel, R S; Elliott, B E

    1989-05-10

    We have shown previously that clonal immunogenic variants of murine mammary adenocarcinoma 10.1 can be isolated after treatment in vitro with the DNA-hypomethylating agent 5-azacytidine (5-aza). Such immunogenic variants frequently express elevated class I major histocompatibility complex antigens relative to the level of expression in the parent tumor and are rejected in syngeneic mice by a T-cell-dependent process. To ascertain whether elevated immunogenicity is a function of increased class I antigen expression, we isolated high class I antigen expressors from 5-aza-treated 10.1 cells by using the fluorescence-activated cell sorter. Clonal variants displaying any increase in class I antigen expression were more efficient stimulators of allo-class I antigen-specific cytolytic T-cell precursors. However, these variants displayed unaltered tumorigenicity in immunocompetent syngeneic mice. Thus, phenotypic changes other than, or in addition to, elevated class I antigen expression cause the reduced tumorigenicity of immunogenic clones of 10.1 cells isolated after 5-aza treatment.

  2. MHC evolution in three salmonid species: a comparison between class II alpha and beta genes.

    PubMed

    Gómez, Daniela; Conejeros, Pablo; Marshall, Sergio H; Consuegra, Sofia

    2010-08-01

    The genes of the major histocompatibility complex (MHC) are amongst the most variable in vertebrates and represent some of the best candidates to study processes of adaptive evolution. However, despite the number of studies available, most of the information on the structure and function of these genes come from studies in mammals and birds in which the MHC class I and II genes are tightly linked and class II alpha exhibits low variability in many cases. Teleost fishes are among the most primitive vertebrates with MHC and represent good organisms for the study of MHC evolution because their class I and class II loci are not physically linked, allowing for independent evolution of both classes of genes. We have compared the diversity and molecular mechanisms of evolution of classical MH class II alpha and class II beta loci in farm populations of three salmonid species: Oncorhynchus kisutch, Oncorhynchus mykiss and Salmo salar. We found single classical class II loci and high polymorphism at both class II alpha and beta genes in the three species. Mechanisms of evolution were common for both class II genes, with recombination and point mutation involved in generating diversity and positive selection acting on the peptide-binding residues. These results suggest that the maintenance of variability at the class IIalpha gene could be a mechanism to increase diversity in the MHC class II in salmonids in order to compensate for the expression of one single classical locus and to respond to a wider array of parasites. PMID:20521040

  3. MHC evolution in three salmonid species: a comparison between class II alpha and beta genes.

    PubMed

    Gómez, Daniela; Conejeros, Pablo; Marshall, Sergio H; Consuegra, Sofia

    2010-08-01

    The genes of the major histocompatibility complex (MHC) are amongst the most variable in vertebrates and represent some of the best candidates to study processes of adaptive evolution. However, despite the number of studies available, most of the information on the structure and function of these genes come from studies in mammals and birds in which the MHC class I and II genes are tightly linked and class II alpha exhibits low variability in many cases. Teleost fishes are among the most primitive vertebrates with MHC and represent good organisms for the study of MHC evolution because their class I and class II loci are not physically linked, allowing for independent evolution of both classes of genes. We have compared the diversity and molecular mechanisms of evolution of classical MH class II alpha and class II beta loci in farm populations of three salmonid species: Oncorhynchus kisutch, Oncorhynchus mykiss and Salmo salar. We found single classical class II loci and high polymorphism at both class II alpha and beta genes in the three species. Mechanisms of evolution were common for both class II genes, with recombination and point mutation involved in generating diversity and positive selection acting on the peptide-binding residues. These results suggest that the maintenance of variability at the class IIalpha gene could be a mechanism to increase diversity in the MHC class II in salmonids in order to compensate for the expression of one single classical locus and to respond to a wider array of parasites.

  4. Restriction fragment length polymorphism within the class I gene loci of the equine major histocompatibility complex

    SciTech Connect

    Alexander, A.J.; Bailey, E.; Woodward, J.G.

    1986-03-05

    Fourteen standard bred horses were serotyped as homozygous for 1 of 6 Equine Leukocyte Antigen (ELA) specificities. DNA was purified from peripheral leukocytes and digested with Hind III or Pvu II. Southern blot hybridization analysis was carried out using a /sup 32/P-labeled mouse cDNA probe (PH2IIa) specific for class I MHC genes. Both enzymes generated blots that contained a large number of bands (23 to 30) per horse. Significant polymorphism existed among most fragment sizes, while a dozen highly conserved band sizes suggested the presence of Qa/tla - like genes. Only 2 animals (both W6's) showed identical band patterns. Polymorphism was greatest between horses of different serotypes and was significantly decreased within serotypes. Unique bands were present on both blots for both W1's and W6's and may account for the serologic specificity seen in ELA W1 and W6 horses. This study is consistent with the findings in other higher vertebrates and implies that the MHC of the horse includes a highly polymorphic class I multigene family.

  5. Genetic polymorphism of the swine major histocompatibility complex ( SLA) class I genes, SLA-1, -2 and -3.

    PubMed

    Ando, Asako; Kawata, Hisako; Shigenari, Atsuko; Anzai, Tatsuya; Ota, Masao; Katsuyama, Yoshihiko; Sada, Masaharu; Goto, Rieko; Takeshima, Shin-Nosuke; Aida, Yoko; Iwanaga, Takahiro; Fujimura, Nobuyuki; Suzuki, Yoshiyuki; Gojobori, Takashi; Inoko, Hidetoshi

    2003-12-01

    In order to identify and characterize genetic polymorphism of the swine major histocompatibility complex ( Mhc: SLA) class I genes, RT-PCR products of the second and third exons of the three SLA classical class I genes, SLA-1, SLA-2 and SLA-3 were subjected to nucleotide determination. These analyses allowed the identification of four, eight and seven alleles at the SLA-1, SLA-2 and SLA-3 loci, respectively, from three different breeds of miniature swine and one mixed breed. Among them, 12 alleles were novel. Construction of a phylogenetic tree using the nucleotide sequences of those 19 alleles indicated that the SLA-1 and -2 genes are more closely related to each other than to SLA-3. Selective forces operating at single amino acid sites of the SLA class I molecules were analyzed by the Adaptsite Package program. Ten positive selection sites were found at the putative antigen recognition sites (ARSs). Among the 14 positively selected sites observed in the human MHC ( HLA) classical class I molecules, eight corresponding positions in the SLA class I molecules were inferred as positively selected. On the other hand, four amino acids at the putative ARSs were identified as negatively selected in the SLA class I molecules. These results suggest that selective forces operating in the SLA class I molecules are almost similar to those of the HLA class I molecules, although several functional sites for antigen and cytotoxic T-lymphocyte recognition by the SLA class I molecules may be different from those of the HLA class I molecules.

  6. New horizons in mouse immunoinformatics: reliable in silico prediction of mouse class I histocompatibility major complex peptide binding affinity.

    PubMed

    Hattotuwagama, Channa K; Guan, Pingping; Doytchinova, Irini A; Flower, Darren R

    2004-11-21

    Quantitative structure-activity relationship (QSAR) analysis is a main cornerstone of modern informatic disciplines. Predictive computational models, based on QSAR technology, of peptide-major histocompatibility complex (MHC) binding affinity have now become a vital component of modern day computational immunovaccinology. Historically, such approaches have been built around semi-qualitative, classification methods, but these are now giving way to quantitative regression methods. The additive method, an established immunoinformatics technique for the quantitative prediction of peptide-protein affinity, was used here to identify the sequence dependence of peptide binding specificity for three mouse class I MHC alleles: H2-D(b), H2-K(b) and H2-K(k). As we show, in terms of reliability the resulting models represent a significant advance on existing methods. They can be used for the accurate prediction of T-cell epitopes and are freely available online ( http://www.jenner.ac.uk/MHCPred). PMID:15534705

  7. Unusual association of beta 2-microglobulin with certain class I heavy chains of the murine major histocompatibility complex.

    PubMed Central

    Bushkin, Y; Tung, J S; Pinter, A; Michaelson, J; Boyse, E A

    1986-01-01

    Class I products of the major histocompatibility complex (MHC) comprise a heavy chain of about 45 kDa noncovalently linked to a 12-kDa beta 2-microglobulin (beta 2m) light chain encoded on a different chromosome. We find that class I products of some mouse strains include an additional 62-kDa molecule which on the following evidence consists of a heavy chain linked covalently with beta 2m. Production of the 62-kDa protein invariably accorded with the occurrence of cysteine at position 121 of the heavy chain (Kb,Kbm1,Kbm3,Dd, and Ld). Substitution of arginine at position 121 invariably accorded with absence of the 62-kDa protein (Kbm6,Kbm7,Kbm9,Kd, and Db). On the basis of observed production versus nonproduction of the 62-kDa molecule, predictions are made regarding residue 121 in class I products for which this is not yet known; namely, Kk, Ks, and Dk, which produce the 62-kDa molecule, as compared with Kj, Qa-2, and TL, which do not. Reported differences in immunologic reactivity between Kb mutant strains with Arg-121 in place of Cys-121 imply that the occurrence of 62-kDa class I products in mice of Cys-121 genotype has functional consequences. Images PMID:3510435

  8. Posttranscriptional Inhibition of Class I Major Histocompatibility Complex Presentation on Hepatocytes and Lymphoid Cells in Chronic Woodchuck Hepatitis Virus Infection

    PubMed Central

    Michalak, Tomasz I.; Hodgson, Paul D.; Churchill, Norma D.

    2000-01-01

    Woodchuck hepatitis virus (WHV), similar to human hepatitis B virus, causes acute liver inflammation that can progress to chronic hepatitis and hepatocellular carcinoma. WHV also invades cells of the host lymphatic system, where it persists for life. We report here that acute and chronic hepadnavirus hepatitis is characterized by a profound difference in the expression of class I major histocompatibility complex (MHC) molecules on the surface of infected hepatocytes and, notably, lymphoid cells. While acute WHV infection is accompanied by the enhanced hepatocyte surface presentation of class I MHC antigen and upregulated transcription of the relevant hepatic genes, inhibition of class I antigen display on liver cells is a uniform hallmark of chronic WHV infection. This inhibition in chronic hepatitis occurs despite augmented (as in acute infection) expression of hepatic genes for class I MHC heavy chain, β2-microglobulin, and transporters associated with antigen processing (TAP1 and TAP2). Further, the class I antigen inhibition is not related to the histological severity of hepatocellular injury, the extent of lymphocytic infiltrations, the level of intrahepatic gamma interferon induction, or the hepatic WHV load. Importantly, the antigen expression is also inhibited on organ lymphoid cells of chronically infected hosts. The results obtained in this study demonstrate that the defective presentation of class I MHC molecules on cells supporting persistent WHV replication is due to viral posttranscriptional interference. This event may diminish the susceptibility of infected hepatocytes to virus-specific T-cell-mediated elimination, hinder virus clearance, and deregulate the class I MHC-dependent functions of the host immune system. This multifarious effect could be critical for perpetuation of liver damage and evasion of the antiviral immunological surveillance in chronic infection and therefore could be supportive of hepadnavirus persistence. PMID:10775584

  9. Characterization and expression of MHC class II alpha and II beta genes in mangrove red snapper (Lutjanus argentimaculatus).

    PubMed

    Wang, Tianyan; Tan, Shangjin; Cai, Zhonghua

    2015-12-01

    The major histocompatibility complex (MHC) class II plays a key role in adaptive immunity by presenting foreign peptides to CD4(+) T cells and by triggering the adaptive immune response. While the structure and function of MHC class II have been well characterized in mammalian, limited research has been done on fishes. In this study, we characterized the gene structure and expression of MHC class II α (Lunar-DAA) and II β (Lunar-DAB) of mangrove red snapper (Lutjanus argentimaculatus). Both genes shared, respectively, a high similarity and typical features with other vertebrate MHC class II α and II β. The phylogenetic analysis of the deduced peptides revealed that both Lunar-DAA and Lunar-DAB were located in the teleost subclass. Western blotting analyses indicated that both MHC class II α and II β were expressed ubiquitously in immune-related cells, tissues and organs, and that MHC class II α and II β chains existed mainly as heterodimers. While it was highly expressed in gills, thymus, head kidney (HK), spleen, head kidney macrophage and spleen leucocytes, MHC class II β chain was expressed with a low abundance in skin, intestine, stomach and heart. The highest expression of MHC class II β in thymus confirmed the conclusion that thymus is one of the primary lymphoid organs in fishes. The detection of MHC class II αβ dimers in HK macrophages and spleen leucocytes indicated that HK macrophages and spleen leucocytes play a critical role in the adaptive immunity in fishes. All these results provide valuable information for understanding the structure of MHC class II α and II β and their function in immune responses.

  10. Characterization and expression of MHC class II alpha and II beta genes in mangrove red snapper (Lutjanus argentimaculatus).

    PubMed

    Wang, Tianyan; Tan, Shangjin; Cai, Zhonghua

    2015-12-01

    The major histocompatibility complex (MHC) class II plays a key role in adaptive immunity by presenting foreign peptides to CD4(+) T cells and by triggering the adaptive immune response. While the structure and function of MHC class II have been well characterized in mammalian, limited research has been done on fishes. In this study, we characterized the gene structure and expression of MHC class II α (Lunar-DAA) and II β (Lunar-DAB) of mangrove red snapper (Lutjanus argentimaculatus). Both genes shared, respectively, a high similarity and typical features with other vertebrate MHC class II α and II β. The phylogenetic analysis of the deduced peptides revealed that both Lunar-DAA and Lunar-DAB were located in the teleost subclass. Western blotting analyses indicated that both MHC class II α and II β were expressed ubiquitously in immune-related cells, tissues and organs, and that MHC class II α and II β chains existed mainly as heterodimers. While it was highly expressed in gills, thymus, head kidney (HK), spleen, head kidney macrophage and spleen leucocytes, MHC class II β chain was expressed with a low abundance in skin, intestine, stomach and heart. The highest expression of MHC class II β in thymus confirmed the conclusion that thymus is one of the primary lymphoid organs in fishes. The detection of MHC class II αβ dimers in HK macrophages and spleen leucocytes indicated that HK macrophages and spleen leucocytes play a critical role in the adaptive immunity in fishes. All these results provide valuable information for understanding the structure of MHC class II α and II β and their function in immune responses. PMID:26454477

  11. Characterization of the oligodeoxynucleotide-mediated inhibition of interferon-gamma-induced major histocompatibility complex class I and intercellular adhesion molecule-1.

    PubMed

    Ramanathan, M; Lantz, M; MacGregor, R D; Garovoy, M R; Hunt, C A

    1994-10-01

    The major histocompatibility complex (MHC) Class I and II genes and intercellular adhesion molecule-1 (ICAM-1) are regulated by interferon-gamma in a variety of cell types. We have previously shown that the oligodeoxynucleotide 5'-GGG GTT GGT TGT GTT GGG TGT TGT GT-RNH2 (oligo I) inhibits the interferon-gamma-mediated enhancement of MHC Class I and ICAM-1 proteins in the K562 cell line. We have now investigated the mechanism of action of oligo I and report that it acts by inhibiting the binding of interferon-gamma to cells. We also show that the dose-response curves, the selectivity profile, and the kinetics of oligo I are consistent with this novel mechanism of action. The dose-response curves for oligo I, obtained using antibodies against the MHC Class I heavy chain, beta 2-microglobulin, or ICAM-1, are almost superimposable at each observation time. MHC Class I induction by 6400 units/ml interferon-alpha or interferon-beta or ICAM-1 enhancement by 800 units/ml tumor necrosis factor-alpha is not inhibited by oligo I. However, the synergistic induction of MHC Class I by mixtures of tumor necrosis factor-alpha and interferon-gamma is inhibited. Oligo I belongs to a class of active oligodeoxynucleotides that inhibits interferon-gamma-induced MHC Class I and ICAM-1 in K562 cells. The activity and potency is sequence-dependent, but remarkably different sequences can have comparable effects. The activity of oligo I in the HeLa S3 cell line inhibits the interferon-gamma-mediated enhancement of both ICAM-1 and MHC Class II DR and the interferon-gamma-mediated reduction in transferrin receptor expression. Thus, oligo I appears to specifically inhibit interferon-gamma-induced changes in protein expression, which is consistent with oligo I acting at an early step(s) in the induction process. Taken together, our results show that oligo I exerts its effects by inhibiting the association of interferon-gamma with the cell surface, which is a novel mechanism of action for

  12. Immunological Functions of the Membrane Proximal Region of MHC Class II Molecules

    PubMed Central

    Harton, Jonathan; Jin, Lei; Hahn, Amy; Drake, Jim

    2016-01-01

    Major histocompatibility complex (MHC) class II molecules present exogenously derived antigen peptides to CD4 T cells, driving activation of naïve T cells and supporting CD4-driven immune functions. However, MHC class II molecules are not inert protein pedestals that simply bind and present peptides. These molecules also serve as multi-functional signaling molecules delivering activation, differentiation, or death signals (or a combination of these) to B cells, macrophages, as well as MHC class II-expressing T cells and tumor cells. Although multiple proteins are known to associate with MHC class II, interaction with STING (stimulator of interferon genes) and CD79 is essential for signaling. In addition, alternative transmembrane domain pairing between class II α and β chains influences association with membrane lipid sub-domains, impacting both signaling and antigen presentation. In contrast to the membrane-distal region of the class II molecule responsible for peptide binding and T-cell receptor engagement, the membrane-proximal region (composed of the connecting peptide, transmembrane domain, and cytoplasmic tail) mediates these “non-traditional” class II functions. Here, we review the literature on the function of the membrane-proximal region of the MHC class II molecule and discuss the impact of this aspect of class II immunobiology on immune regulation and human disease. PMID:27006762

  13. Immunological Functions of the Membrane Proximal Region of MHC Class II Molecules.

    PubMed

    Harton, Jonathan; Jin, Lei; Hahn, Amy; Drake, Jim

    2016-01-01

    Major histocompatibility complex (MHC) class II molecules present exogenously derived antigen peptides to CD4 T cells, driving activation of naïve T cells and supporting CD4-driven immune functions. However, MHC class II molecules are not inert protein pedestals that simply bind and present peptides. These molecules also serve as multi-functional signaling molecules delivering activation, differentiation, or death signals (or a combination of these) to B cells, macrophages, as well as MHC class II-expressing T cells and tumor cells. Although multiple proteins are known to associate with MHC class II, interaction with STING (stimulator of interferon genes) and CD79 is essential for signaling. In addition, alternative transmembrane domain pairing between class II α and β chains influences association with membrane lipid sub-domains, impacting both signaling and antigen presentation. In contrast to the membrane-distal region of the class II molecule responsible for peptide binding and T-cell receptor engagement, the membrane-proximal region (composed of the connecting peptide, transmembrane domain, and cytoplasmic tail) mediates these "non-traditional" class II functions. Here, we review the literature on the function of the membrane-proximal region of the MHC class II molecule and discuss the impact of this aspect of class II immunobiology on immune regulation and human disease. PMID:27006762

  14. Dissociation of β2-microglobulin determines the surface quality control of major histocompatibility complex class I molecules.

    PubMed

    Montealegre, Sebastián; Venugopalan, Vaishnavi; Fritzsche, Susanne; Kulicke, Corinna; Hein, Zeynep; Springer, Sebastian

    2015-07-01

    Major histocompatibility complex class I proteins, which present antigenic peptides to cytotoxic T lymphocytes at the surface of all nucleated cells, are endocytosed and destroyed rapidly once their peptide ligand has dissociated. The molecular mechanism of this cellular quality control process, which prevents rebinding of exogenous peptides and thus erroneous immune responses, is unknown. To identify the nature of the decisive step in endocytic sorting of class I molecules and its location, we have followed the removal of optimally and suboptimally peptide-loaded murine H-2K(b) class I proteins from the cell surface. We find that the binding of their light chain, β2-microglobulin (β2m), protects them from endocytic destruction. Thus, the extended survival of suboptimally loaded K(b) molecules at 25°C is attributed to decreased dissociation of β2m. Because all forms of K(b) are constantly internalized but little β2m-receptive heavy chain is present at the cell surface, it is likely that β2m dissociation and recognition of the heavy chain for lysosomal degradation take place in an endocytic compartment.

  15. Tetraspan microdomains distinct from lipid rafts enrich select peptide-MHC class II complexes.

    PubMed

    Kropshofer, H; Spindeldreher, S; Röhn, T A; Platania, N; Grygar, C; Daniel, N; Wölpl, A; Langen, H; Horejsi, V; Vogt, A B

    2002-01-01

    Complexes of peptide and major histocompatibility complex (MHC) class II are expressed on the surface of antigen-presenting cells but their molecular organization is unknown. Here we show that subsets of MHC class II molecules localize to membrane microdomains together with tetraspan proteins, the peptide editor HLA-DM and the costimulator CD86. Tetraspan microdomains differ from other membrane areas such as lipid rafts, as they enrich MHC class II molecules carrying a selected set of peptide antigens. Antigen-presenting cells deficient in tetraspan microdomains have a reduced capacity to activate CD4+ T cells. Thus, the organization of uniformly loaded peptide-MHC class II complexes in tetraspan domains may be a very early event that determines both the composition of the immunological synapse and the quality of the subsequent T helper cell response.

  16. Contrasting patterns of selection acting on MHC class I and class II DRB genes in the Alpine marmot (Marmota marmota).

    PubMed

    Kuduk, K; Johanet, A; Allainé, D; Cohas, A; Radwan, J

    2012-08-01

    The major histocompatibility complex (MHC) genes code for proteins that play a critical role in the immune system response. The MHC genes are among the most polymorphic genes in vertebrates, presumably due to balancing selection. The two MHC classes appear to differ in the rate of evolution, but the reasons for this variation are not well understood. Here, we investigate the level of polymorphism and the evolution of sequences that code for the peptide-binding regions of MHC class I and class II DRB genes in the Alpine marmot (Marmota marmota). We found evidence for four expressed MHC class I loci and two expressed MHC class II loci. MHC genes in marmots were characterized by low polymorphism, as one to eight alleles per putative locus were detected in 38 individuals from three French Alps populations. The generally limited degree of polymorphism, which was more pronounced in class I genes, is likely due to bottleneck the populations undergone. Additionally, gene duplication within each class might have compensated for the loss of polymorphism at particular loci. The two gene classes showed different patterns of evolution. The most polymorphic of the putative loci, Mama-DRB1, showed clear evidence of historical positive selection for amino acid replacements. However, no signal of positive selection was evident in the MHC class I genes. These contrasting patterns of sequence evolution may reflect differences in selection pressures acting on class I and class II genes.

  17. Variation in positively selected major histocompatibility complex class I loci in rufous-collared sparrows (Zonotrichia capensis).

    PubMed

    Jones, Matthew R; Cheviron, Zachary A; Carling, Matthew D

    2014-12-01

    The major histocompatibility complex (MHC) is a highly variable family of genes involved in parasite recognition and the initiation of adaptive immune system responses. Variation in MHC loci is maintained primarily through parasite-mediated selection or disassortative mate choice. To characterize MHC diversity of rufous-collared sparrows (Zonotrichia capensis), an abundant South American passerine, we examined allelic and nucleotide variation in MHC class I exon 3 using pyrosequencing. Exon 3 comprises a substantial portion of the peptide-binding region (PBR) of class I MHC and thus plays an important role in intracellular pathogen defense. We identified 98 putatively functional alleles that produce 56 unique protein sequences across at least 6 paralogous loci. Allelic diversity per individual and exon-wide nucleotide diversity were relatively low; however, we found specific amino acid positions with high nucleotide diversity and signatures of positive selection (elevated d N /d S ) that may correspond to the PBR. Based on the variation in physicochemical properties of amino acids at these "positively selected sites," we identified ten functional MHC supertypes. Spatial variation in nucleotide diversity and the number of MHC alleles, proteins, and supertypes per individual suggests that environmental heterogeneity may affect patterns of MHC diversity. Furthermore, populations with high MHC diversity have higher prevalence of avian malaria, consistent with parasite-mediated selection on MHC. Together, these results provide a framework for subsequent investigations of selective agents acting on MHC in Z. capensis. PMID:25186067

  18. Pathogenicity of Bovine Neonatal Pancytopenia-associated vaccine-induced alloantibodies correlates with Major Histocompatibility Complex class I expression

    PubMed Central

    Benedictus, Lindert; Luteijn, Rutger D.; Otten, Henny; Jan Lebbink, Robert; van Kooten, Peter J. S.; Wiertz, Emmanuel J. H. J.; Rutten, Victor P. M. G.; Koets, Ad P.

    2015-01-01

    Bovine Neonatal Pancytopenia (BNP), a fatal bleeding syndrome of neonatal calves, is caused by maternal alloantibodies absorbed from colostrum and is characterized by lymphocytopenia, thrombocytopenia and bone marrow hypoplasia. An inactivated viral vaccine is the likely source of alloantigens inducing BNP-associated alloantibodies in the dam. In this study the specificity of BNP alloantibodies was assessed and was linked to the pathology of BNP. We demonstrated that Major Histocompatibility Complex class I (MHC I) and Very Late Antigen-3, an integrin α3/β1 heterodimer, were the major targets of BNP alloantibodies. However, alloantibody binding to various bovine cell types correlated with MHC I expression, rather than integrin β1 or α3 expression. Likewise, alloantibody-dependent complement-mediated cell lysis correlated strongly with MHC I expression. Examination of several tissues of third trimester bovine foetuses revealed that cells, shown to be affected in calves with BNP, were characterized by high MHC class I expression and high levels of alloantibody binding. We conclude that in spite of the heterogeneous specificity of BNP associated maternal alloantibodies, MHC I-specific antibodies mediate the pathogenicity of BNP in the calf and that cells with high MHC I expression were preferentially affected in BNP. PMID:26235972

  19. Persistent measles virus infection enhances major histocompatibility complex class I expression and immunogenicity of murine neuroblastoma cells.

    PubMed

    Gopas, J; Itzhaky, D; Segev, Y; Salzberg, S; Trink, B; Isakov, N; Rager-Zisman, B

    1992-01-01

    The effect of persistent measles virus infection on the expression of major histocompatibility complex (MHC) class I antigens was studied. Mouse neuroblastoma cells C1300, clone NS20Y, were persistently infected with the Edmonston strain of measles virus. The persistently infected cell line, NS20Y/MS, expressed augmented levels of both H-2Kk and H-2Dd MHC class I glycoproteins. Activation of two interferon(IFN)-induced enzymes, known to be part of the IFN system: (2'-5')oligoadenylate synthetase and double-stranded-RNA-activated protein kinase, was detected. Measles-virus-infected cells elicited cytotoxic T lymphocytes that recognized and lysed virus-infected and uninfected neuroblastoma cells in an H-2-restricted fashion. Furthermore, immunization of mice with persistently infected cells conferred resistance to tumor growth after challenge with the highly malignant NS20Y cells. The rationale for using measles virus for immunotherapy is that most patients develop lifelong immunity after recovery or vaccination from this infection. Patients developing cancer are likely to have memory cells. A secondary response induced by measles-virus-infected cells may therefore induce an efficient immune response against non-infected tumour cells.

  20. Pathogenicity of Bovine Neonatal Pancytopenia-associated vaccine-induced alloantibodies correlates with Major Histocompatibility Complex class I expression.

    PubMed

    Benedictus, Lindert; Luteijn, Rutger D; Otten, Henny; Lebbink, Robert Jan; van Kooten, Peter J S; Wiertz, Emmanuel J H J; Rutten, Victor P M G; Koets, Ad P

    2015-01-01

    Bovine Neonatal Pancytopenia (BNP), a fatal bleeding syndrome of neonatal calves, is caused by maternal alloantibodies absorbed from colostrum and is characterized by lymphocytopenia, thrombocytopenia and bone marrow hypoplasia. An inactivated viral vaccine is the likely source of alloantigens inducing BNP-associated alloantibodies in the dam. In this study the specificity of BNP alloantibodies was assessed and was linked to the pathology of BNP. We demonstrated that Major Histocompatibility Complex class I (MHC I) and Very Late Antigen-3, an integrin α3/β1 heterodimer, were the major targets of BNP alloantibodies. However, alloantibody binding to various bovine cell types correlated with MHC I expression, rather than integrin β1 or α3 expression. Likewise, alloantibody-dependent complement-mediated cell lysis correlated strongly with MHC I expression. Examination of several tissues of third trimester bovine foetuses revealed that cells, shown to be affected in calves with BNP, were characterized by high MHC class I expression and high levels of alloantibody binding. We conclude that in spite of the heterogeneous specificity of BNP associated maternal alloantibodies, MHC I-specific antibodies mediate the pathogenicity of BNP in the calf and that cells with high MHC I expression were preferentially affected in BNP. PMID:26235972

  1. Amino Acid Polymorphisms in Hepatitis C Virus Core Affect Infectious Virus Production and Major Histocompatibility Complex Class I Molecule Expression

    PubMed Central

    Tasaka-Fujita, Megumi; Sugiyama, Nao; Kang, Wonseok; Masaski, Takahiro; Murayama, Asako; Yamada, Norie; Sugiyama, Ryuichi; Tsukuda, Senko; Watashi, Koichi; Asahina, Yasuhiro; Sakamoto, Naoya; Wakita, Takaji; Shin, Eui-Cheol; Kato, Takanobu

    2015-01-01

    Amino acid (aa) polymorphisms in the hepatitis C virus (HCV) genotype 1b core protein have been reported to be a potent predictor for poor response to interferon (IFN)-based therapy and a risk factor for hepatocarcinogenesis. We investigated the effects of these polymorphisms with genotype 1b/2a chimeric viruses that contained polymorphisms of Arg/Gln at aa 70 and Leu/Met at aa 91. We found that infectious virus production was reduced in cells transfected with chimeric virus RNA that had Gln at aa 70 (aa70Q) compared with RNA with Arg at aa 70 (aa70R). Using flow cytometry analysis, we confirmed that HCV core protein accumulated in aa70Q clone transfected cells, and it caused a reduction in cell-surface expression of major histocompatibility complex (MHC) class I molecules induced by IFN treatment through enhanced protein kinase R phosphorylation. We could not detect any effects due to the polymorphism at aa 91. In conclusion, the polymorphism at aa 70 was associated with efficiency of infectious virus production, and this deteriorated virus production in strains with aa70Q resulted in the intracellular accumulation of HCV proteins and attenuation of MHC class I molecule expression. These observations may explain the strain-associated resistance to IFN-based therapy and hepatocarcinogenesis of HCV. PMID:26365522

  2. Regulation of calreticulin-major histocompatibility complex (MHC) class I interactions by ATP.

    PubMed

    Wijeyesakere, Sanjeeva Joseph; Gagnon, Jessica K; Arora, Karunesh; Brooks, Charles L; Raghavan, Malini

    2015-10-13

    The MHC class I peptide loading complex (PLC) facilitates the assembly of MHC class I molecules with peptides, but factors that regulate the stability and dynamics of the assembly complex are largely uncharacterized. Based on initial findings that ATP, in addition to MHC class I-specific peptide, is able to induce MHC class I dissociation from the PLC, we investigated the interaction of ATP with the chaperone calreticulin, an endoplasmic reticulum (ER) luminal, calcium-binding component of the PLC that is known to bind ATP. We combined computational and experimental measurements to identify residues within the globular domain of calreticulin, in proximity to the high-affinity calcium-binding site, that are important for high-affinity ATP binding and for ATPase activity. High-affinity calcium binding by calreticulin is required for optimal nucleotide binding, but both ATP and ADP destabilize enthalpy-driven high-affinity calcium binding to calreticulin. ATP also selectively destabilizes the interaction of calreticulin with cellular substrates, including MHC class I molecules. Calreticulin mutants that affect ATP or high-affinity calcium binding display prolonged associations with monoglucosylated forms of cellular MHC class I, delaying MHC class I dissociation from the PLC and their transit through the secretory pathway. These studies reveal central roles for ATP and calcium binding as regulators of calreticulin-substrate interactions and as key determinants of PLC dynamics.

  3. Lipopeptides: a novel antigen repertoire presented by major histocompatibility complex class I molecules.

    PubMed

    Morita, Daisuke; Sugita, Masahiko

    2016-10-01

    Post-translationally modified peptides, such as those containing either phosphorylated or O-glycosylated serine/threonine residues, may be presented to cytotoxic T lymphocytes (CTLs) by MHC class I molecules. Most of these modified peptides are captured in the MHC class I groove in a similar manner to that for unmodified peptides. N-Myristoylated 5-mer lipopeptides have recently been identified as a novel chemical class of MHC class I-presented antigens. The rhesus classical MHC class I allele, Mamu-B*098, was found to be capable of binding N-myristoylated lipopeptides and presenting them to CTLs. A high-resolution X-ray crystallographic analysis of the Mamu-B*098:lipopeptide complex revealed that the myristic group as well as conserved C-terminal serine residue of the lipopeptide ligand functioned as anchors, whereas the short stretch of three amino acid residues located in the middle of the lipopeptides was only exposed externally with the potential to interact directly with specific T-cell receptors. Therefore, the modes of lipopeptide-ligand interactions with MHC class I and with T-cell receptors are novel and fundamentally distinct from that for MHC class I-presented peptides. Another lipopeptide-presenting MHC class I allele has now been identified, leading us to the prediction that MHC class I molecules may be separated on a functional basis into two groups: one presenting long peptides and the other presenting short lipopeptides. Since the N-myristoylation of viral proteins is often linked to pathogenesis, CTLs capable of sensing N-myristoylation may serve to control pathogenic viruses, raising the possibility for the development of a new type of lipopeptide vaccine. PMID:27402593

  4. Murine retroviruses control class I major histocompatibility antigen gene expression via a trans effect at the transcriptional level.

    PubMed

    Wilson, L D; Flyer, D C; Faller, D V

    1987-07-01

    Moloney murine leukemia virus (M-MuLV) and Moloney murine sarcoma virus (M-MSV) exert a regulatory effect on the class I genes of the murine major histocompatibility complex (MHC). We have previously shown that M-MuLV infection of mouse fibroblasts results in a substantial increase in cell surface expression of H-2K, H-2D, and H-2L proteins, whereas M-MSV, upon coinfection of the same cells, is apparently able to override the MuLV-induced increase in H-2 expression. As a result of this modulation, immune recognition of the infected cells is profoundly altered. Our efforts have been directed toward elucidating the molecular basis for this phenomenon. We report here that stimulation of interferon production as a result of infection with MuLV does not occur and, therefore, is not the cause of MuLV-induced enhancement of MHC expression. Control of H-2 class I and beta 2-microglobulin gene expression by M-MuLV, and probably by M-MSV, takes place at the transcriptional level as indicated by nuclear runoff studies and analysis of steady-state mRNA levels. Our demonstration that M-MuLV controls expression of widely separated endogenous cellular genes (those coding for H-2D, H-2K, H-2L, and beta 2-microglobulin), transfected class I MHC genes, and unintegrated chimeric genes consisting of fragments of class I MHC genes linked to sequences encoding a procaryotic enzyme, chloramphenicol acetyltransferase, suggests that M-MuLV exerts its effect in trans and not by proviral integration in the vicinity of the H-2 gene complex. Finally, we show that the sequences of at least one MHC gene, which are responsive to trans regulation by M-MuLV, lie within 1.2 kilobases upstream of the initiation codon for that gene.

  5. Unusual association of. beta. /sub 2/-microglobulin with certain class I heavy chains of the murine major histocompatibility complex

    SciTech Connect

    Bushkin, Y.; Tung, J.S.; Pinter, A.; Michaelson, J.; Boyse, E.A.

    1986-01-01

    Class I products of the major histocompatibility complex (MHC) comprise a heavy chain of about 45 kDa noncovalently linked to a 12-kDa ..beta../sub 2/-microglobulin (..beta../sub 2/m) light chain encoded on a different chromosome. The authors find that class I products of some mouse strains include an additional 62-kDa molecule which on the following evidence consists of a heavy chain linked covalently with ..beta../sub 2/m. Production of the 62-kDa protein invariably accorded with the occurrence of cysteine at position 121 of the heavy chain (K/sup b/, K/sup bm3/, D/sup d/, and L/sup d/). Substitution of arginine at position 121 invariably accorded with absence of the 62-kDa protein (K/sup bm6/, K/sup bm7/, K/sup bm9/, K/sup d/, and D/sup b/). On the basis of observed production versus nonproduction of the 62-kDa molecule, predictions are made regarding residue 121 in class I products for which this is not yet known; namely, K/sup k/, K/sup s/, and D/sup k/, which produce the 62-kDa molecule, as compared with K/sup j/, Qa-2, and TL, which do not. Reported differences in immunologic reactivity between K/sup b/ mutant strains with Arg-121 in place of Cys-121 imply that the occurrence of 62-kDa class I products in mice of Cys-121 genotype has functional consequences. Lymph node cells were labelled with (/sup 35/S)cysteine and Na/sup 125/I.

  6. Organization and evolution of D region class I genes in the mouse major histocompatibility complex

    PubMed Central

    1986-01-01

    Chromosome walking has been used to study the organization of the class I genes in the D and Qa regions of the MHC of the BALB/c mouse and in the D region of the AKR mouse. Five and eight class I genes are found in the D and Qa regions of the BALB/c mouse, respectively, while the AKR mouse contains only a single class I D region gene that has been identified by transfection as the Dk gene. Restriction map homologies and crosshybridization experiments suggest that the multiple class I genes in the D region of the BALB/c mouse have been generated by unequal crossing-over involving class I genes from the Qa region. The expanded D region of BALB/c and other H-2d haplotype mouse strains appears to be metastable, since evidence for gene contraction in the Dd region has been found in two mutant strains. Thus the D region and also the Qa region class I genes are in a dynamic state, evolving by gene expansion and contraction. PMID:3701254

  7. Coronavirus induction of class I major histocompatibility complex expression in murine astrocytes is virus strain specific

    PubMed Central

    1994-01-01

    Neurotropic strains of mouse hepatitis viruses (MHV) such as MHV-A59 (A59) and MHV-4 (JHMV) cause acute and chronic encephalomyelitis and demyelination in susceptible strains of mice and rats. They are widely used as models of human demyelinating diseases such as multiple sclerosis (MS), in which immune mechanisms are thought to participate in the development of lesions in the central nervous system (CNS). The effects of MHV infection on target cell functions in the CNS are not well understood, but A59 has been shown to induce the expression of MHC class I molecules in glial cells after in vivo and in vitro infection. Changes in class I expression in infected cells may contribute to the immunopathogenesis of MHV infection in the CNS. In this communication, a large panel of MHV strains was tested for their ability to stimulate class I expression in primary astrocytes in vitro. The data show that the more hepatotropic strains, such as MHV-A59, MHV-1, MHV-2, MHV-3, MHV-D, MHV-K, and MHV-NuU, were potent inducers of class I expression in astrocytes during acute infection, measured by radioimmunoassay. The Kb molecule was preferentially expressed over Db. By contrast, JHMV and several viral strains derived from it did not stimulate the expression of class I molecules. Assays of virus infectivity indicated that the class I-inducing activity did not correlate with the ability of the individual viral strain to replicate in astrocytes. However, exposure of the viruses or the supernatants from infected astrocytes to ultraviolet light abolished the class I-inducing activity, indicating that infectious virus is required for class I expression. These data also suggest that class I expression was induced directly by virus infection, and not by the secretion of a soluble substance into the medium by infected astrocytes. Finally, analyses of A59/JHMV recombinant viral strains suggest that class I-inducing activity resides in one of the A59 structural genes. PMID:8064222

  8. Transfer of cloned human class I major histocompatibility complex genes into HLA mutant human lymphoblastoid cells.

    PubMed Central

    Shimizu, Y; Koller, B; Geraghty, D; Orr, H; Shaw, S; Kavathas, P; DeMars, R

    1986-01-01

    Three new kinds of recombinant DNA constructs were used to transfer cloned human class I HLA genes (A2 and B8) into unique HLA mutant lymphoblastoid cells: pHeBo(x): a class I gene, "x," in plasmid vector pHeBo, which contains a hygromycin resistance gene and Epstein-Barr virus oriP element that sustains extrachromosomal replication; pHPT(x): gene x in a vector with a hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene; pHPTe(x): gene x in a vector with the HPRT gene and oriP element. Cell surface class I antigen expression was strong in transferents made with class I-deficient lymphoblastoid cell line mutants .144 (A-null), .53 (B-null), and .184 (A-null, B-null). Transferents expressing HLA-A2 were recognized specifically by HLA-A2-specific cytotoxic T lymphocytes. When introduced on either of the vectors with the Epstein-Barr virus oriP element, the class I gene replicated extrachromosomally and was lost at rates of 0.2 to 0.3 per cell division. When introduced with vector pHPT (lacking Epstein-Barr virus oriP), the B8 gene was inserted at different chromosomal locations. Introduction of the HLA-B8 gene failed to restore antigen expression by HLA-B-null mutant .174, providing evidence that, unlike mutants exemplified by .53, .144, and .184, some HLA antigen loss mutants are deficient in a trans-acting function needed for class I antigen expression. Of more general interest, the results obtained with HLA class I genes in vectors that replicate extrachromosomally suggest ways of relating genic expression to chromatin structure and function and of attempting to clone functional human centromeres. Images PMID:3023867

  9. Transfer of cloned human class I major histocompatibility complex genes into HLA mutant human lymphoblastoid cells.

    PubMed

    Shimizu, Y; Koller, B; Geraghty, D; Orr, H; Shaw, S; Kavathas, P; DeMars, R

    1986-04-01

    Three new kinds of recombinant DNA constructs were used to transfer cloned human class I HLA genes (A2 and B8) into unique HLA mutant lymphoblastoid cells: pHeBo(x): a class I gene, "x," in plasmid vector pHeBo, which contains a hygromycin resistance gene and Epstein-Barr virus oriP element that sustains extrachromosomal replication; pHPT(x): gene x in a vector with a hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene; pHPTe(x): gene x in a vector with the HPRT gene and oriP element. Cell surface class I antigen expression was strong in transferents made with class I-deficient lymphoblastoid cell line mutants .144 (A-null), .53 (B-null), and .184 (A-null, B-null). Transferents expressing HLA-A2 were recognized specifically by HLA-A2-specific cytotoxic T lymphocytes. When introduced on either of the vectors with the Epstein-Barr virus oriP element, the class I gene replicated extrachromosomally and was lost at rates of 0.2 to 0.3 per cell division. When introduced with vector pHPT (lacking Epstein-Barr virus oriP), the B8 gene was inserted at different chromosomal locations. Introduction of the HLA-B8 gene failed to restore antigen expression by HLA-B-null mutant .174, providing evidence that, unlike mutants exemplified by .53, .144, and .184, some HLA antigen loss mutants are deficient in a trans-acting function needed for class I antigen expression. Of more general interest, the results obtained with HLA class I genes in vectors that replicate extrachromosomally suggest ways of relating genic expression to chromatin structure and function and of attempting to clone functional human centromeres. PMID:3023867

  10. Vaccine-induced antibodies linked to bovine neonatal pancytopenia (BNP) recognize cattle major histocompatibility complex class I (MHC I).

    PubMed

    Deutskens, Fabian; Lamp, Benjamin; Riedel, Christiane M; Wentz, Eveline; Lochnit, Günter; Doll, Klaus; Thiel, Heinz-Jürgen; Rümenapf, Till

    2011-01-01

    A mysterious disease affecting calves, named bovine neonatal pancytopenia (BNP), emerged in 2007 in several European countries. Epidemiological studies revealed a connection between BNP and vaccination with an inactivated vaccine against bovine virus diarrhea (BVD). Alloantibodies reacting with blood leukocytes of calves were detected in serum and colostrum of dams, which have given birth to calves affected by BNP. To understand the linkage between vaccination and the development of alloantibodies, we determined the antigens reacting with these alloantibodies. Immunoprecipitation of surface proteins from bovine leukocytes and kidney cells using sera from dams with a confirmed case of BNP in their gestation history reacted with two dominant protein species of 44 and 12 kDa. These proteins were not detected by sera from dams, free of BVDV and not vaccinated against BVD, and from sera of animals vaccinated with a different inactivated BVD vaccine. The 44 kDa protein was identified by mass spectrometry analysis as MHC I, the other as β-2-microglobulin. The presence of major histocompatibility complex class I (MHC I) in the vaccine was confirmed by Western blot using a MHC I specific monoclonal antibody. A model of BNP pathogenesis is proposed. PMID:21878124

  11. Transgenic mice with enhanced neuronal major histocompatibility complex class I expression recover locomotor function better after spinal cord injury.

    PubMed

    Joseph, M Selvan; Bilousova, Tina; Zdunowski, Sharon; Wu, Zhongqi-Phyllis; Middleton, Blake; Boudzinskaia, Maia; Wong, Bonnie; Ali, Noore; Zhong, Hui; Yong, Jing; Washburn, Lorraine; Escande-Beillard, Nathalie; Dang, Hoa; Edgerton, V Reggie; Tillakaratne, Niranjala J K; Kaufman, Daniel L

    2011-03-01

    Mice that are deficient in classical major histocompatibility complex class I (MHCI) have abnormalities in synaptic plasticity and neurodevelopment and have more extensive loss of synapses and reduced axon regeneration after sciatic nerve transection, suggesting that MHCI participates in maintaining synapses and axon regeneration. Little is known about the biological consequences of up-regulating MHCI's expression on neurons. To understand MHCI's neurobiological activity better, and in particular its role in neurorepair after injury, we have studied neurorepair in a transgenic mouse model in which classical MHCI expression is up-regulated only on neurons. Using a well-established spinal cord injury (SCI) model, we observed that transgenic mice with elevated neuronal MHCI expression had significantly better recovery of locomotor abilities after SCI than wild-type mice. Although previous studies have implicated inflammation as both deleterious and beneficial for recovery after SCI, our results point directly to enhanced neuronal MHCI expression as a beneficial factor for promoting recovery of locomotor function after SCI.

  12. Enhanced expression of class I major histocompatibility complex gene (Dk) products on immunogenic variants of a spontaneous murine carcinoma.

    PubMed

    Carlow, D A; Kerbel, R S; Feltis, J T; Elliott, B E

    1985-08-01

    Both immunogenic and nonimmunogenic variant clones were isolated from a recently obtained spontaneous murine adenocarcinoma after treatment (xenogenization) with either the mutagen ethyl methanesulfonate or the DNA hypomethylating agent, and "gene activator," 5-azacytidine. Clonal analysis of the untreated tumor population confirmed that immunogenic variants arose as a consequence of the xenogenization protocol. At a dose of 10(6) cells per mouse, nonimmunogenic variants, like the parental tumor line, grew progressively in normal syngeneic recipients. In contrast, immunogenic variants were rejected in normal syngeneic mice and grew progressively only in T-cell-deficient nude mice. Serologic analysis of the respective clonal variants revealed that immunogenic variants expressed substantially elevated (fourfold to tenfold) levels of class I H-2Dk antigen relative to parental or nonimmunogenic cell lines. Two variants exhibiting marginal immunogenicity expressed high and low levels of major histocompatibility complex (MHC) antigen, respectively suggesting that elevated MHC expression, although possibly a contributing factor, did not account for the immunogenic phenotype in all cases. Finally, the immunogenic phenotype of two variants decayed with time in culture. Clones in the process of reversion lost their elevated Dk gene expression and became progressively more tumorigenic in normal syngeneic mice. Together, these data are consistent with a hypothesis that elevated MHC expression can contribute to the immunogenic phenotype of originally low MHC-expressing tumors and that the reduced level of MHC observed in certain clinical cancers may have significant implications with regard to immunologic aspects of the tumor-host relationship.

  13. Major Histocompatibility Complex class I proteins are critical for maintaining neuronal structural complexity in the aging brain.

    PubMed

    Lazarczyk, Maciej J; Kemmler, Julia E; Eyford, Brett A; Short, Jennifer A; Varghese, Merina; Sowa, Allison; Dickstein, Daniel R; Yuk, Frank J; Puri, Rishi; Biron, Kaan E; Leist, Marcel; Jefferies, Wilfred A; Dickstein, Dara L

    2016-01-01

    Major histocompatibility complex class I (MHCI) proteins have been implicated in neuronal function through the modulation of neuritogenesis, synaptogenesis, synaptic plasticity, and memory consolidation during development. However, the involvement of MHCI in the aged brain is unclear. Here we demonstrate that MHCI deficiency results in significant dendritic atrophy along with an increase in thin dendritic spines and a reduction in stubby spines in the hippocampus of aged (12 month old) mice. Ultrastructural analyses revealed a decrease in spine head diameter and post synaptic density (PSD) area, as well as an increase in overall synapse density, and non-perforated, small spines. Interestingly, we found that the changes in synapse density and morphology appear relatively late (after the age of 6 months). Finally, we found a significant age dependent increase in the levels of the glutamate receptor, GluN2B in aged MHCI knockout mice, with no change in GluA2/3, VGluT1, PSD95 or synaptophysin. These results indicate that MHCI may be also be involved in maintaining brain integrity at post-developmental stages notably in the modulation of neuronal and spine morphology and synaptic function during non-pathological aging which could have significant implications for cognitive function. PMID:27229916

  14. Expression of major histocompatibility complex class I-related chain A/B (MICA/B) in pancreatic carcinoma.

    PubMed

    Dambrauskas, Zilvinas; Svensson, Helena; Joshi, Meghnad; Hyltander, Anders; Naredi, Peter; Iresjö, Britt-Marie

    2014-01-01

    Major histocompatibility complex class I-related chain A and B (MICA/B) are two stress-inducible ligands that bind to the immunoreceptor NKG2D and play an important role in mediating cytotoxicity of NK and T cells. Release of MIC molecules from the cell surface is thought to constitute an immune escape mechanism of tumor cells and thus could be associated with more aggressive course of tumor growth. In this study, we investigated the expression of MICA/B in ductal pancreatic carcinoma and serum in relation to tumor stage, differentiation and survival. MICA/B expression in tumor tissues and sera from patients with pancreatic cancer were analyzed by immunohistochemical staining (IHC), western blotting and ELISA, respectively. MICA/B expression was present in 17 of 22 (77%) of the tumors but not in normal pancreatic ductal epithelial cells. Poorly differentiated tumors showed more pronounced MICA/B expression compared to differentiated tumors, but did not correlate significantly to other tumor characteristics. MICA/B-negative tumors displayed significantly lower incidence of lymph node metastases (p<0.01), and less mortality within 3 years following resection (p<0.02). In conclusion, tissue levels of MICA/B expression were elevated in pancreatic cancer cells without elevated levels in serum, despite well-recognized acute phase reactants in serum. Poorly differentiated tumors showed high MICA/B expression, which was related to extended tumor lymph node metastases and less frequent long-term survival.

  15. Constraints within major histocompatibility complex class I restricted peptides: Presentation and consequences for T-cell recognition

    SciTech Connect

    Theodossis, Alex; Guillonneau, Carole; Welland, Andrew; Ely, Lauren K.; Clements, Craig S.; Williamson, Nicholas A.; Webb, Andrew I.; Wilce, Jacqueline A.; Mulder, Roger J.; Dunstone, Michelle A.; Doherty, Peter C.; McCluskey, James; Purcell, Anthony W.; Turner, Stephen J.; Rossjohn, Jamie

    2010-03-24

    Residues within processed protein fragments bound to major histocompatibility complex class I (MHC-I) glycoproteins have been considered to function as a series of 'independent pegs' that either anchor the peptide (p) to the MHC-I and/or interact with the spectrum of {alpha}{beta}-T-cell receptors (TCRs) specific for the pMHC-I epitope in question. Mining of the extensive pMHC-I structural database established that many self- and viral peptides show extensive and direct interresidue interactions, an unexpected finding that has led us to the idea of 'constrained' peptides. Mutational analysis of two constrained peptides (the HLA B44 restricted self-peptide (B44DP{alpha}-EEFGRAFSF)) and an H2-D{sup b} restricted influenza peptide (D{sup b}PA, SSLENFRAYV) demonstrated that the conformation of the prominently exposed arginine in both peptides was governed by interactions with MHC-I-orientated flanking residues from the peptide itself. Using reverse genetics in a murine influenza model, we revealed that mutation of an MHC-I-orientated residue (SSLENFRAYV {yields} SSLENARAYV) within the constrained PA peptide resulted in a diminished cytotoxic T lymphocyte (CTL) response and the recruitment of a limited pMHC-I specific TCR repertoire. Interactions between individual peptide positions can thus impose fine control on the conformation of pMHC-I epitopes, whereas the perturbation of such constraints can lead to a previously unappreciated mechanism of viral escape.

  16. Major histocompatibility complex class I molecules protect motor neurons from astrocyte-induced toxicity in amyotrophic lateral sclerosis.

    PubMed

    Song, SungWon; Miranda, Carlos J; Braun, Lyndsey; Meyer, Kathrin; Frakes, Ashley E; Ferraiuolo, Laura; Likhite, Shibi; Bevan, Adam K; Foust, Kevin D; McConnell, Michael J; Walker, Christopher M; Kaspar, Brian K

    2016-04-01

    Astrocytes isolated from individuals with amyotrophic lateral sclerosis (ALS) are toxic to motor neurons (MNs) and play a non-cell autonomous role in disease pathogenesis. The mechanisms underlying the susceptibility of MNs to cell death remain unclear. Here we report that astrocytes derived from either mice bearing mutations in genes associated with ALS or human subjects with ALS reduce the expression of major histocompatibility complex class I (MHCI) molecules on MNs; reduced MHCI expression makes these MNs susceptible to astrocyte-induced cell death. Increasing MHCI expression on MNs increases survival and motor performance in a mouse model of ALS and protects MNs against astrocyte toxicity. Overexpression of a single MHCI molecule, HLA-F, protects human MNs from ALS astrocyte-mediated toxicity, whereas knockdown of its receptor, the killer cell immunoglobulin-like receptor KIR3DL2, on human astrocytes results in enhanced MN death. Thus, our data indicate that, in ALS, loss of MHCI expression on MNs renders them more vulnerable to astrocyte-mediated toxicity. PMID:26928464

  17. Selective modulation of MHC class II chaperons by a novel IFN-γ-inducible class II transactivator variant in lung adenocarcinoma A549 cells.

    PubMed

    Chiu, Bau-Lin; Li, Chia-Hsuan; Chang, Chien-Chung

    2013-10-11

    Class II transactivator (CIITA) plays a critical role in controlling major histocompatibility complex (MHC) class II gene expression. In this study, two novel alternatively spliced variants of human interferon (IFN)-γ-inducible CIITA, one missing exon 7 (CIITAΔE7), the other with TAG inserted at exon 4/5 junction (CIITA-TAG), were identified and characterized. Both variants are naturally occurring since they are present in primary cells. Unlike CIITA-TAG, CIITAΔE7 is expressed more abundantly in lung adenocarcinoma A549 cells than in the non-transformed counterpart BEAS-2B cells following IFN-γ stimulation. Transfection experiments showed that CIITAΔE7 induced a markedly lower level of surface HLA-DR, -DP, -DQ expression than CIITA-TAG in A549 cells but not in BEAS-2B cells, although both variants elicited similar amounts of total DR, DP, and DQ proteins. This differential effect was correlated with, in A549 cells, decreased expression of Ii and HLA-DM genes, along with increased expression of HLA-DO genes. Ii and HLA-DM are chaperons assisting in HLA class II assembly, while HLA-DO functions to inhibit endosomal peptide loading and HLA class II membrane transport. These findings raise the possibility that CIITAΔE7 interacts with unknown cancer-associated factors to selectively modulate genes involved in the assembly and transport of HLA class II molecules.

  18. Evolutionary history of black grouse major histocompatibility complex class IIB genes revealed through single locus sequence-based genotyping

    PubMed Central

    2013-01-01

    Background Gene duplications are frequently observed in the Major Histocompatibility Complex (MHC) of many species, and as a consequence loci belonging to the same MHC class are often too similar to tell apart. In birds, single locus genotyping of MHC genes has proven difficult due to concerted evolution homogenizing sequences at different loci. But studies on evolutionary history, mode of selection and heterozygosity correlations on the MHC cannot be performed before it is possible to analyse duplicated genes separately. In this study we investigate the architecture and evolution of the MHC class IIB genes in black grouse. We developed a sequence-based genotyping method for separate amplification of the two black grouse MHC class IIB genes BLB1 and BLB2. Based on this approach we are able to study differences in structure and selection between the two genes in black grouse and relate these results to the chicken MHC structure and organization. Results Sequences were obtained from 12 individuals and separated into alleles using the software PHASE. We compared nucleotide diversity measures and employed selection tests for BLB1 and BLB2 to explore their modes of selection. Both BLB1 and BLB2 are transcribed and display classic characteristics of balancing selection as predicted for expressed MHC class IIB genes. We found evidence for both intra- and interlocus recombination or gene conversion, as well as indication for positive but differential selection at both loci. Moreover, the two loci appear to be linked. Phylogenetic analyses revealed orthology of the black grouse MHC class IIB genes to the respective BLB loci in chicken. Conclusions The results indicate that the duplication of the BLB gene occurred before the species divergence into black grouse, chicken and pheasant. Further, we conclude that BLB1 and BLB2 in black grouse are subjected to homogenizing concerted evolution due to interlocus genetic exchange after species divergence. The loci are in linkage

  19. Lectin-deficient calnexin is capable of binding class I histocompatibility molecules in vivo and preventing their degradation.

    PubMed

    Leach, Michael R; Williams, David B

    2004-03-01

    Calnexin is a membrane-bound lectin of the endoplasmic reticulum (ER) that binds transiently to newly synthesized glycoproteins. By interacting with oligosaccharides of the form Glc(1)Man(9)GlcNAc(2), calnexin enhances the folding of glycoprotein substrates, retains misfolded variants in the ER, and in some cases participates in their degradation. Calnexin has also been shown to bind polypeptides in vivo that do not possess a glycan of this form and to function in vitro as a molecular chaperone for nonglycosylated proteins. To test the relative importance of the lectin site compared with the polypeptide-binding site, we have generated six calnexin mutants defective in oligosaccharide binding using site-directed mutagenesis. Expressed as glutathione S-transferase fusions, these mutants were still capable of binding ERp57, a thiol oxidoreductase, and preventing the aggregation of a nonglycosylated substrate, citrate synthase. They were, however, unable to bind Glc(1) Man(9)GlcNAc(2) oligosaccharide and were compromised in preventing the aggregation of the monoglucosylated substrate jack bean alpha-mannosidase. Two of these mutants were then engineered into full-length calnexin for heterologous expression in Drosophila cells along with the murine class I histocompatibility molecules K(b) and D(b) as model glycoproteins. In this system, lectin site-defective calnexin was able to replace wild type calnexin in forming a complex with K(b) and D(b) heavy chains and preventing their degradation. Thus, at least for class I molecules, the lectin site of calnexin is dispensable for some of its chaperone functions. PMID:14699098

  20. Early Endosomes Are Required for Major Histocompatiblity Complex Class II Transport to Peptide-loading Compartments

    PubMed Central

    Brachet, Valérie; Péhau-Arnaudet, Gérard; Desaymard, Catherine; Raposo, Graça; Amigorena, Sebastian

    1999-01-01

    Antigen presentation to CD4+ T lymphocytes requires transport of newly synthesized major histocompatibility complex (MHC) class II molecules to the endocytic pathway, where peptide loading occurs. This step is mediated by a signal located in the cytoplasmic tail of the MHC class II-associated Ii chain, which directs the MHC class II-Ii complexes from the trans-Golgi network (TGN) to endosomes. The subcellular machinery responsible for the specific targeting of MHC class II molecules to the endocytic pathway, as well as the first compartments these molecules enter after exit from the TGN, remain unclear. We have designed an original experimental approach to selectively analyze this step of MHC class II transport. Newly synthesized MHC class II molecules were caused to accumulate in the Golgi apparatus and TGN by incubating the cells at 19°C, and early endosomes were functionally inactivated by in vivo cross-linking of transferrin (Tf) receptor–containing endosomes using Tf-HRP complexes and the HRP-insoluble substrate diaminobenzidine. Inactivation of Tf-containing endosomes caused a marked delay in Ii chain degradation, peptide loading, and MHC class II transport to the cell surface. Thus, early endosomes appear to be required for delivery of MHC class II molecules to the endocytic pathway. Under cross-linking conditions, most αβIi complexes accumulated in tubules and vesicles devoid of γ-adaptin and/or mannose-6-phosphate receptor, suggesting an AP1-independent pathway for the delivery of newly synthesized MHC class II molecules from the TGN to endosomes. PMID:10473634

  1. Functional analysis of Mycoplasma arthritidis-derived mitogen interactions with class II molecules.

    PubMed Central

    Bernatchez, C; Al-Daccak, R; Mayer, P E; Mehindate, K; Rink, L; Mecheri, S; Mourad, W

    1997-01-01

    The ability of superantigens (SAGs) to trigger various cellular events via major histocompatibility complex (MHC) class II molecules is largely mediated by their mode of interaction. Having two MHC class II binding sites, staphylococcal enterotoxin A (SEA) is able to dimerize MHC class II molecules on the cell surface and consequently induces cytokine gene expression in human monocytes. In contrast, cross-linking with specific monoclonal antibodies or T-cell receptor is required for staphylococcal enterotoxin B (SEB) and toxic shock syndrome toxin 1 (TSST-1) to induce similar responses. In the present study, we report how Mycoplasma arthritidis-derived mitogen (MAM) may interact with MHC class II molecules to induce cytokine gene expression in human monocytes. The data presented indicate that MAM-induced cytokine gene expression in human monocytes is Zn2+ dependent. The MAM-induced response is completely abolished by pretreatment with SEA mutants that have lost their capacity to bind either the MHC class II alpha or beta chain, with wild-type SEB, or with wild-type TSST-1, suggesting that MAM induces cytokine gene expression most probably by inducing dimerization of class II molecules. In addition, it seems that SEA and MAM interact with the same or overlapping binding sites on the MHC class II beta chain and, on the other hand, that they bind to the alpha chain most probably through the regions that are involved in SEB and TSST-1 binding. PMID:9169724

  2. TNF-α Induces Macroautophagy and Regulates MHC Class II Expression in Human Skeletal Muscle Cells*

    PubMed Central

    Keller, Christian W.; Fokken, Claudia; Turville, Stuart G.; Lünemann, Anna; Schmidt, Jens; Münz, Christian; Lünemann, Jan D.

    2011-01-01

    Macroautophagy, a homeostatic process that shuttles cytoplasmic constituents into endosomal and lysosomal compartments, has recently been shown to deliver antigens for presentation on major histocompatibility complex (MHC) class II molecules. Skeletal muscle fibers show a high level of constitutive macroautophagy and express MHC class II molecules upon immune activation. We found that tumor necrosis factor-α (TNF-α), a monokine overexpressed in inflammatory myopathies, led to a marked up-regulation of macroautophagy in skeletal myocytes. Furthermore, TNF-α augmented surface expression of MHC class II molecules in interferon-γ (IFN-γ)-treated myoblasts. The synergistic effect of TNF-α and IFN-γ on the induction of MHC class II surface expression was not reflected by higher intracellular human leukocyte antigen (HLA)-DR levels and was reversed by macroautophagy inhibition, suggesting that TNF-α facilitates antigen processing via macroautophagy for more efficient MHC class II loading. Muscle biopsies from patients with sporadic inclusion body myositis, a well defined myopathy with chronic inflammation, showed that over 20% of fibers that contained autophagosomes costained for MHC class II molecules and that more than 40% of double-positive muscle fibers had contact with CD4+ and CD8+ immune cells. These findings establish a mechanism through which TNF-α regulates both macroautophagy and MHC class II expression and suggest that macroautophagy-mediated antigen presentation contributes to the immunological environment of the inflamed human skeletal muscle. PMID:20980264

  3. Ethanol Metabolism Alters Major Histocompatibility Complex Class I-Restricted Antigen Presentation In Liver Cells

    PubMed Central

    Osna, Natalia A.; White, Ronda L.; Thiele, Geoffrey M.; Donohue, Terrence M.

    2009-01-01

    The proteasome is a major enzyme that cleaves proteins for antigen presentation. Cleaved peptides traffic to the cell surface, where they are presented in the context of MHC class I. Recognition of these complexes by cytotoxic T lymphocytes is crucial for elimination of cells bearing “non-self” proteins. Our previous studies revealed that ethanol suppresses proteasome function in ethanol-metabolizing liver cells. We hypothesized that proteasome suppression reduces the hydrolysis of antigenic peptides, thereby decreasing the presentation of the peptide-MHC class I-complexes on the cell surface. To test this, we used the mouse hepatocyte cell line (CYP2E1/ADH-transfected HepB5 cells) or primary mouse hepatocytes, both derived from livers of C57Bl/6 mice, which present the ovalbumin peptide, SIINFEKL, complexed with H2Kb. To induce H2Kb expression, HepB5 cells were treated with interferon gamma (IFNγ) and then exposed to ethanol. In these cells, ethanol metabolism decreased not only proteasome activity, but also hydrolysis of the C-extended peptide, SIINFEKL-TE and the presentation of SIINFEKL-H2Kb complexes measured after the delivery of SIINFEKL-TE to cytoplasm. The suppressive effects of ethanol were, in part, attributed to ethanol-elicited impairment of IFNγ signaling. However, in primary hepatocytes, even in the absence of IFNγ, we observed a similar decline in proteasome activity and antigen presentation after ethanol exposure. We conclude that proteasome function is directly suppressed by ethanol metabolism and indirectly, by preventing the activating effects of IFNγ. Ethanol-elicited reduction in proteasome activity contributes to the suppression of SIINFEKL-H2Kb presentation on the surface of liver cells. Immune response to viral antigens plays a crucial role in the pathogenesis of hepatitis C or B viral infections (HCV and HBV, respectively). Professional antigen-presenting cells (dendritic cells and macrophages) are responsible for priming the

  4. Altered transcription of genes coding for class I histocompatibility antigens in murine tumor cells

    PubMed Central

    1983-01-01

    Three murine tumors induced by Moloney murine leukemia virus (M-MLV) which exhibited loss of some or all H-2 class I antigens at the cell surface were analyzed at the DNA and RNA level with molecular probes specific of H-2 heavy chains and beta 2-microglobulin sequences. No observable difference could be detected at the DNA level between the tumors and the parent animals. However, a decrease in H-2 mRNA was observed, especially in phenotypically H-2 negative tumor, BM5R, where H-2 transcripts were at least 30-fold less abundant. These results show that an H-2-negative character may result from a general alteration in the transcription of H-2 genes, which could reflect some kind of regulatory process. PMID:6311935

  5. Early failure of Class II resin composite versus Class II amalgam restorations placed by dental students.

    PubMed

    Overton, J D; Sullivan, Diane J

    2012-03-01

    Using the information from remake request slips in a dental school's predoctoral clinic, we examined the short-term survival of Class II resin composite restorations versus Class II dental amalgam restorations. In the student clinic, resin composite is used in approximately 58 percent of Class II restorations placed, and dental amalgam is used in the remaining 42 percent. In the period examined, Class II resin composite restorations were ten times more likely to be replaced at no cost to the patient than Class II dental amalgam restorations. A total of eighty-four resin composite restorations and six amalgam restorations were replaced due to an identified failure.

  6. MOLECULAR GENETICS OF THE SWINE MAJOR HISTOCOMPATIBILITY COMPLEX, THE SLA COMPLEX

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The swine major histocompatibility complex (MHC) or swine leukocyte antigen (SLA) complex is one of the most gene-dense regions in the swine genome. It consists of three major gene clusters, the SLA class I, class III and class II regions, that span ~1.1, 0.7 and 0.5 Mb, respectively, making the swi...

  7. DNA sequence of the Peromyscus leucopus MHC class II gene Aa (MhcPeleAa)

    SciTech Connect

    Crew, M.D.; Bates, L.M.

    1996-09-01

    The genus Peromyscus has been extensively studied by populations biologists and ecologists for over eighty years, with P. leucopus (the white-footed mouse) being one of the most intensively investigated species. Polymorphic major histocompatibility complex (MHC) genes have proven useful in population genetic studies and might be helpful in understanding the population dynamics of Peromyscus species which are ubiquitously distributed over North and Central America. Polymorphism of P. leucopus MHC (MhcPele) class II genes was evident by restriction fragment length polymorphism (RFLP) analyses using human and mouse probes and Pele class II loci exhibited degrees of polymorphism similar to H2 class II genes (A-like>E-like). 8 refs., 2 figs.

  8. Determinant selection of major histocompatibility complex class I- restricted antigenic peptides is explained by class I-peptide affinity and is strongly influenced by nondominant anchor residues

    PubMed Central

    1994-01-01

    The contribution of major histocompatibility complex (MHC) class I- peptide affinity to immunodominance of particular peptide antigens (Ags) in the class I-restricted cytotoxic T lymphocyte (CTL) response is not clearly established. Therefore, we have compared the H-2Kb- restricted binding and presentation of the immunodominant ovalbumin (OVA)257-264 (SIINFEKL) determinant to that of a subdominant OVA determinant OVA55-62 (KVVRFDKL). Immunodominance of OVA257-264 was not attributable to the specific T cell repertoire but correlated instead with more efficient Ag presentation. This enhanced Ag presentation could be accounted for by the higher affinity of Kb/OVA257-264 compared with Kb/OVA55-62 despite the presence of a conserved Kb-binding motif in both peptides. Kinetic binding studies using purified soluble H-2Kb molecules (Kbs) and biosensor techniques indicated that the Kon for association of OVA257-264-C6 and Kbs at 25 degrees C was integral of 10- fold faster (5.9 x 10(3) M-1 s-1 versus 6.5 x 10(2) M-1 s-1), and the Koff approximately twofold slower (9.1 x 10(-6) s-1 versus 1.6 x 10(-5) s-1), than the rate constants for interaction of OVA55-62-C6 and Kbs. The association of these peptides with Kb was significantly influenced by multiple residues at presumed nonanchor sites within the peptide sequence. The contribution of each peptide residue to Kb-binding was dependent upon the sequence context and the summed contributions were not additive. Thus the affinity of MHC class I-peptide binding is a critical factor controlling presentation of peptide Ag and immunodominance in the class I-restricted CTL response. PMID:7523572

  9. Genetic Variation on the BAT1-NFKBIL1-LTA Region of Major Histocompatibility Complex Class III Associates with Periodontitis

    PubMed Central

    Marchesani, Marja; Vlachopoulou, Efthymia; Mäntylä, Päivi; Paju, Susanna; Buhlin, Kåre; Suominen, Anna L.; Contreras, Johanna; Knuuttila, Matti; Hernandez, Marcela; Huumonen, Sisko; Nieminen, Markku S.; Perola, Markus; Sinisalo, Juha; Lokki, Marja-Liisa; Pussinen, Pirkko J.

    2014-01-01

    Periodontitis is a chronic inflammatory disease with a multifactorial etiology. We investigated whether human major histocompatibility complex (MHC) polymorphisms (6p21.3) are associated with periodontal parameters. Parogene 1 population samples (n = 169) were analyzed with 13,245 single nucleotide polymorphisms (SNPs) of the MHC region. Eighteen selected SNPs (P ≤ 0.001) were replicated in Parogene 2 population samples (n = 339) and the Health 2000 Survey (n = 1,420). All subjects had a detailed clinical and radiographic oral health examination. Serum lymphotoxin-α (LTA) concentrations were measured in the Parogene populations, and the protein was detected in inflamed periodontal tissue. In the Parogene 1 population, 10 SNPs were associated with periodontal parameters. The strongest associations emerged from the parameters bleeding on probing (BOP) and a probing pocket depth (PPD) of ≥6 mm with the genes BAT1, NFKBIL1, and LTA. Six SNPs, rs11796, rs3130059, rs2239527, rs2071591, rs909253, and rs1041981 (r2, ≥0.92), constituted a risk haplotype. In the Parogene 1 population, the haplotype had the strongest association with the parameter BOP, a PPD of ≥6 mm, and severe periodontitis with odds ratios (95% confidence intervals) of 2.63 (2.21 to 3.20), 2.90 (2.37 to 3.52), and 3.10 (1.63 to 5.98), respectively. These results were replicated in the other two populations. High serum LTA concentrations in the Parogene population were associated with the periodontitis risk alleles of the LTA SNPs (rs909253 and rs1041981) of the haplotype. In addition, the protein was expressed in inflamed gingival connective tissue. We identified a novel BAT1-NFKBIL1-LTA haplotype as a significant contributor to the risk of periodontitis. The genetic polymorphisms in the MHC class III region may be functionally important in periodontitis susceptibility. PMID:24566624

  10. Molecular Architecture of the Major Histocompatibility Complex Class I-binding Site of Ly49 Natural Killer Cell Receptors*

    PubMed Central

    Deng, Lu; Cho, Sangwoo; Malchiodi, Emilio L.; Kerzic, Melissa C.; Dam, Julie; Mariuzza, Roy A.

    2008-01-01

    Natural killer (NK) cells play a vital role in the detection and destruction of virally infected and tumor cells during innate immune responses. The highly polymorphic Ly49 family of NK receptors regulates NK cell function by sensing major histocompatibility complex class I (MHC-I) molecules on target cells. Despite the determination of two Ly49-MHC-I complex structures, the molecular features of Ly49 receptors that confer specificity for particular MHC-I alleles have not been identified. To understand the functional architecture of Ly49-binding sites, we determined the crystal structures of Ly49C and Ly49G and completed refinement of the Ly49C-H-2Kb complex. This information, combined with mutational analysis of Ly49A, permitted a structure-based classification of Ly49s that we used to dissect the binding site into three distinct regions, each having different roles in MHC recognition. One region, located at the center of the binding site, has a similar structure across the Ly49 family and mediates conserved interactions with MHC-I that contribute most to binding. However, the preference of individual Ly49s for particular MHC-I molecules is governed by two regions that flank the central region and are structurally more variable. One of the flanking regions divides Ly49s into those that recognize both H-2D and H-2K versus only H-2D ligands, whereas the other discriminates among H-2D or H-2K alleles. The modular design of Ly49-binding sites provides a framework for predicting the MHC-binding specificity of Ly49s that have not been characterized experimentally. PMID:18426793

  11. Molecular Architecture of the Major Histocompatibility Complex Class I-Binding Site of Ly49 Natural Killer Cell Receptors

    SciTech Connect

    Deng,L.; Cho, S.; Malchiodi, E.; Kerzic, M.; Dam, J.; Mariuzza, R.

    2008-01-01

    Natural killer (NK) cells play a vital role in the detection and destruction of virally infected and tumor cells during innate immune responses. The highly polymorphic Ly49 family of NK receptors regulates NK cell function by sensing major histocompatibility complex class I (MHC-I) molecules on target cells. Despite the determination of two Ly49-MHC-I complex structures, the molecular features of Ly49 receptors that confer specificity for particular MHC-I alleles have not been identified. To understand the functional architecture of Ly49-binding sites, we determined the crystal structures of Ly49C and Ly49G and completed refinement of the Ly49C-H-2Kb complex. This information, combined with mutational analysis of Ly49A, permitted a structure-based classification of Ly49s that we used to dissect the binding site into three distinct regions, each having different roles in MHC recognition. One region, located at the center of the binding site, has a similar structure across the Ly49 family and mediates conserved interactions with MHC-I that contribute most to binding. However, the preference of individual Ly49s for particular MHC-I molecules is governed by two regions that flank the central region and are structurally more variable. One of the flanking regions divides Ly49s into those that recognize both H-2D and H-2K versus only H-2D ligands, whereas the other discriminates among H-2D or H-2K alleles. The modular design of Ly49-binding sites provides a framework for predicting the MHC-binding specificity of Ly49s that have not been characterized experimentally.

  12. High-throughput engineering and analysis of peptide binding to class II MHC.

    PubMed

    Jiang, Wei; Boder, Eric T

    2010-07-27

    Class II major histocompatibility complex (MHC-II) proteins govern stimulation of adaptive immunity by presenting antigenic peptides to CD4+ T lymphocytes. Many allelic variants of MHC-II exist with implications in peptide presentation and immunity; thus, high-throughput experimental tools for rapid and quantitative analysis of peptide binding to MHC-II are needed. Here, we present an expression system wherein peptide and MHC-II are codisplayed on the surface of yeast in an intracellular association-dependent manner and assayed by flow cytometry. Accordingly, the relative binding of different peptides and/or MHC-II variants can be assayed by genetically manipulating either partner, enabling the application of directed evolution approaches for high-throughput characterization or engineering. We demonstrate the application of this tool to map the side-chain preference for peptides binding to HLA-DR1 and to evolve novel HLA-DR1 mutants with altered peptide-binding specificity.

  13. Role of Plasmacytoid Dendritic Cells for Aberrant Class II Expression in Exocrine Glands from Estrogen-Deficient Mice of Healthy Background

    PubMed Central

    Arakaki, Rieko; Nagaoka, Ai; Ishimaru, Naozumi; Yamada, Akiko; Yoshida, Satoko; Hayashi, Yoshio

    2009-01-01

    Although it has been well documented that aberrant major histocompatibility complex class II molecules may contribute to the development of autoimmune disorders, the precise mechanisms responsible for their tissue-specific expression remain unknown. Here we show that estrogen deficiency induces aberrant class II major histocompatibility complex expression in exocrine glands via interactions between epithelial cells and plasmacytoid dendritic cells. Relatively modest but functionally significant expression levels of major histocompatibility complex class II and class II transactivator molecules were observed in the exocrine glands of ovariectomized (Ovx) C57BL/6 (B6) mice, but were not seen in the exocrine glands of control B6 mice. We observed that the salivary dendritic cells adjacent to the apoptotic epithelial cells positive for terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling, were activated in Ovx mice, but were not activated in control mice. We obtained evidence that the salivary gland cells express both interferon regulatory factor-1 and class II transactivator type IV molecules in Ovx mice. Salivary gland cells from Ovx mice were also capable of inducing the activation of antigen-specific T cells from OT-II transgenic mice. These findings indicate that estrogen deficiency initiates class II transactivator type IV mRNA expression in exocrine glands via interactions between epithelial cells and plasmacytoid dendritic cells, suggesting that plasmacytoid dendritic cells play a pivotal role in gender-based autoimmune disorders in postmenopausal women. PMID:19359524

  14. Major histocompatibility complex class I-specific and -restricted killing of beta 2-microglobulin-deficient cells by CD8+ cytotoxic T lymphocytes.

    PubMed Central

    Glas, R; Franksson, L; Ohlén, C; Höglund, P; Koller, B; Ljunggren, H G; Kärre, K

    1992-01-01

    Cytotoxic T lymphocytes (CTLs) recognize major histocompatibility complex (MHC) class I molecules, normally composed of a heavy chain, a beta 2-microglobulin (beta 2m), and peptide antigens. beta 2m is considered essential for the assembly and intracellular transport of MHC class I molecules as well as their peptide presentation to CTLs. Contrary to this dogma, we now report the generation of allospecific and restricted CD8+ and TCR alpha beta+ CTLs (where TCR is T-cell receptor) capable of killing beta 2m-deficient cells. Such CTLs were obtained by priming mice with live allogeneic beta 2m- spleen cells or mutant lymphoma cells producing MHC class I protein but no detectable beta 2m. Although both beta 2m- and beta 2m-expressing lymphoma cells were rejected in allogeneic mice, only the former were efficient inducers of CTLs recognizing beta 2m- cells. These CTLs were MHC class I (H-2Kb or Db)-specific and CD8-dependent and did not require serum as a source of external beta 2m in the culture. They could be induced across major and minor histocompatibility barriers. The H-2-restricted CTLs generated in the latter case failed to kill the antigen-processing-deficient target RMA-S cells. The results show that MHC class I heavy chains in beta 2m- cells can be transported to the cell surface and act as antigens or antigen-presenting molecules to allospecific and MHC-restricted CTLs. PMID:1454824

  15. Major histocompatibility complex class I evolution in songbirds: universal primers, rapid evolution and base compositional shifts in exon 3

    PubMed Central

    Alcaide, Miguel; Liu, Mark

    2013-01-01

    Genes of the Major Histocompatibility Complex (MHC) have become an important marker for the investigation of adaptive genetic variation in vertebrates because of their critical role in pathogen resistance. However, despite significant advances in the last few years the characterization of MHC variation in non-model species still remains a challenging task due to the redundancy and high variation of this gene complex. Here we report the utility of a single pair of primers for the cross-amplification of the third exon of MHC class I genes, which encodes the more polymorphic half of the peptide-binding region (PBR), in oscine passerines (songbirds; Aves: Passeriformes), a group especially challenging for MHC characterization due to the presence of large and complex MHC multigene families. In our survey, although the primers failed to amplify exon 3 from two suboscine passerine birds, they amplified exon 3 of multiple MHC class I genes in all 16 species of oscine songbirds tested, yielding a total of 120 sequences. The 16 songbird species belong to 14 different families, primarily within the Passerida, but also in the Corvida. Using a conservative approach based on the analysis of cloned amplicons (n = 16) from each species, we found between 3 and 10 MHC sequences per individual. Each allele repertoire was highly divergent, with the overall number of polymorphic sites per species ranging from 33 to 108 (out of 264 sites) and the average number of nucleotide differences between alleles ranging from 14.67 to 43.67. Our survey in songbirds allowed us to compare macroevolutionary dynamics of exon 3 between songbirds and non-passerine birds. We found compelling evidence of positive selection acting specifically upon peptide-binding codons across birds, and we estimate the strength of diversifying selection in songbirds to be about twice that in non-passerines. Analysis using comparative methods suggest weaker evidence for a higher GC content in the 3rd codon position of

  16. Major histocompatibility class I molecules present Urtica dioica agglutinin, a superantigen of vegetal origin, to T lymphocytes.

    PubMed

    Rovira, P; Buckle, M; Abastado, J P; Peumans, W J; Truffa-Bachi, P

    1999-05-01

    The Urtica dioica agglutinin (UDA) shares with the superantigens the property of activating T cell subsets bearing particular Vbeta segments of the TCR. However, UDA is a lectin capable of binding to many glycoproteins on cell membranes. The implication of MHC versus other glycoproteins in UDA presentation was presently studied. Using mutant mice lacking MHC class I (MHC-I), MHC class II (MHC-II) or both MHC antigens, we provided evidence that MHC-I and MHC-II molecules serve as UDA receptors. Presentation by either one of these molecules ensured similar T cell responses and co-stimulatory signals were mandatory for optimal T cell activation and proliferation both in MHC-I and MHC-II contexts. Remarkably, in the absence of MHC molecules, UDA could not be efficiently presented to T cells by other glycosylated proteins. Surface plasmon resonance studies were used to confirm the binding of UDA to MHC-I molecules using a fusion protein consisting of MHC-I domains and beta2-microglobulin. The results indicated that the interaction between UDA and MHC-I molecules implicated lectin-binding site(s) of UDA. Taken together, our data demonstrate that, in addition to MHC-II antigens, MHC-I molecules serve as an alternative ligand for UDA.

  17. Molecular characterization of three Mhc class II B haplotypes in the ring-necked pheasant.

    PubMed

    Wittzell, H; von Schantz, T; Zoorob, R; Auffray, C

    1994-01-01

    We investigated the class II B genes in a free-ranging population of the ring-necked pheasant Phasianus colchicus by a combination of restriction fragment length polymorphism (RFLP), polymerase chain reaction (PCR), and DNA sequencing. Special attention was paid to the variation in the second exon, which encodes the peptide-binding beta 1-domain. The population was introduced, but it still exhibited major histocompatibility complex polymorphism with at least three segregating class II B haplotypes and consequently six genotypes. We found two class II B genes associated with each haplotype. The class II B genes of birds had until then only been molecularly characterized in the domestic chicken. The pheasant genes were highly variable, although one of the amplified sequences was found in two different haplotypes. Taken together, the most polymorphic positions (residues 37 and 38) were not identical in any of the predicted protein sequences, but all except one of the motifs had already been found in the domestic chicken. Structurally important features in mammalian class II B genes were generally conserved also in the pheasant sequences, but the loss of a potential salt bridge constituent (Arg72) in several sequences may suggest a slightly different structure of the adjacent parts of the peptide-binding groove. The pheasant genes are most closely related to the so called B-LBII family in the chicken, indicating that this represents a major line of development among avian class II B genes.

  18. Polycomb recruitment at the Class II transactivator gene.

    PubMed

    Boyd, Nathaniel H; Morgan, Julie E; Greer, Susanna F

    2015-10-01

    The Class II Transactivator (CIITA) is the master regulator of Major Histocompatibility Class II (MHC II) genes. Transcription of CIITA through the IFN-γ inducible CIITA promoter IV (CIITA pIV) during activation is characterized by a decrease in trimethylation of histone H3 lysine 27 (H3K27me3), catalyzed by the histone methyltransferase Enhancer of Zeste Homolog 2 (EZH2). While EZH2 is the known catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) and is present at the inactive CIITA pIV, the mechanism of PRC2 recruitment to mammalian promoters remains unknown. Here we identify two DNA-binding proteins, which interact with and regulate PRC2 recruitment to CIITA pIV. We demonstrate Yin Yang 1 (YY1) and Jumonji domain containing protein 2 (JARID2) are binding partners along with EZH2 in mammalian cells. Upon IFN-γ stimulation, YY1 dissociates from CIITA pIV while JARID2 binding to CIITA pIV increases, suggesting novel roles for these proteins in regulating expression of CIITA pIV. Knockdown of YY1 and JARID2 yields decreased binding of EZH2 and H3K27me3 at CIITA pIV, suggesting important roles for YY1 and JARID2 at CIITA pIV. JARID2 knockdown also results in significantly elevated levels of CIITA mRNA upon IFN-γ stimulation. This study is the first to identify novel roles of YY1 and JARID2 in the epigenetic regulation of the CIITA pIV by recruitment of PRC2. Our observations indicate the importance of JARID2 in CIITA pIV silencing, and also provide a novel YY1-JARID2-PRC2 regulatory complex as a possible explanation of differential PRC2 recruitment at inducible versus permanently silenced genes.

  19. Transcription specificity of the class Ib genes SLA-6, SLA-7 and SLA-8 of the swine major histocompatibility complex and comparison with class Ia genes.

    PubMed

    Kusza, S; Flori, L; Gao, Y; Teillaud, A; Hu, R; Lemonnier, G; Bosze, Z; Bourneuf, E; Vincent-Naulleau, S; Rogel-Gaillard, C

    2011-10-01

    Our aim was to analyse the transcription levels of the three non-classical class Ib genes SLA-6, SLA-7 and SLA-8 of the swine major histocompatibility complex in various tissues and conditions and to compare them to the transcription levels of classical class Ia genes. Twenty-five adult tissues from two pig breeds, pig renal PK15 cells infected with the Pseudorabies virus, and peripheral blood mononuclear cells (PBMCs) stimulated by lipopolysaccharide or a mixture of phorbol myristate acetate and ionomycin were included in our study. Relative transcription was quantified by quantitative real-time PCR. On average, in adult tissues and PBMCs and compared to SLA-6, the transcription level of SLA-Ia genes was 100-1000 times higher, the level of SLA-8 was 10-20 times higher, and that of SLA-7 was five times higher. Thus, SLA-8 is the most transcribed SLA-Ib gene, followed by the SLA-7 and SLA-6 genes. The highest transcription levels of SLA-Ib transcripts were found in the lymphoid organs, followed by the lung and the digestive tract. The tissue variability of expression levels was widest for the SLA-6 gene, with a 1:32 ratio between the lowest and highest levels in contrast to a 1:12 ratio for the SLA-7 and SLA-8 genes and a 1:16 ratio for the SLA-Ia genes. During PK-15 infection and PBMC stimulation, SLA-Ia and SLA-8 genes were downregulated, whereas SLA-6 and SLA-7 were upregulated, downregulated or not significantly modified. Our overall results confirm the tissue-wide transcription of the three SLA-Ib genes and suggest that they have complementary roles.

  20. Acute Viral Escape Selectively Impairs Nef-Mediated Major Histocompatibility Complex Class I Downmodulation and Increases Susceptibility to Antiviral T Cells.

    PubMed

    Weiler, Andrea M; Das, Arpita; Akinyosoye, Oluwasayo; Cui, Sherry; O'Connor, Shelby L; Scheef, Elizabeth A; Reed, Jason S; Panganiban, Antonito T; Sacha, Jonah B; Rakasz, Eva G; Friedrich, Thomas C; Maness, Nicholas J

    2016-02-01

    Nef-specific CD8(+) T lymphocytes (CD8TL) are associated with control of simian immunodeficiency virus (SIV) despite extensive nef variation between and within animals. Deep viral sequencing of the immunodominant Mamu-B*017:01-restricted Nef165-173IW9 epitope revealed highly restricted evolution. A common acute escape variant, T170I, unexpectedly and uniquely degraded Nef's major histocompatibility complex class I (MHC-I) downregulatory capacity, rendering the virus more vulnerable to CD8TL targeting other epitopes. These data aid in a mechanistic understanding of Nef functions and suggest means of immunity-mediated control of lentivirus replication. PMID:26637459

  1. Acute Viral Escape Selectively Impairs Nef-Mediated Major Histocompatibility Complex Class I Downmodulation and Increases Susceptibility to Antiviral T Cells.

    PubMed

    Weiler, Andrea M; Das, Arpita; Akinyosoye, Oluwasayo; Cui, Sherry; O'Connor, Shelby L; Scheef, Elizabeth A; Reed, Jason S; Panganiban, Antonito T; Sacha, Jonah B; Rakasz, Eva G; Friedrich, Thomas C; Maness, Nicholas J

    2015-12-04

    Nef-specific CD8(+) T lymphocytes (CD8TL) are associated with control of simian immunodeficiency virus (SIV) despite extensive nef variation between and within animals. Deep viral sequencing of the immunodominant Mamu-B*017:01-restricted Nef165-173IW9 epitope revealed highly restricted evolution. A common acute escape variant, T170I, unexpectedly and uniquely degraded Nef's major histocompatibility complex class I (MHC-I) downregulatory capacity, rendering the virus more vulnerable to CD8TL targeting other epitopes. These data aid in a mechanistic understanding of Nef functions and suggest means of immunity-mediated control of lentivirus replication.

  2. Acute Viral Escape Selectively Impairs Nef-Mediated Major Histocompatibility Complex Class I Downmodulation and Increases Susceptibility to Antiviral T Cells

    PubMed Central

    Weiler, Andrea M.; Das, Arpita; Akinyosoye, Oluwasayo; Cui, Sherry; O'Connor, Shelby L.; Scheef, Elizabeth A.; Reed, Jason S.; Panganiban, Antonito T.; Sacha, Jonah B.; Rakasz, Eva G.; Friedrich, Thomas C.

    2015-01-01

    Nef-specific CD8+ T lymphocytes (CD8TL) are associated with control of simian immunodeficiency virus (SIV) despite extensive nef variation between and within animals. Deep viral sequencing of the immunodominant Mamu-B*017:01-restricted Nef165–173IW9 epitope revealed highly restricted evolution. A common acute escape variant, T170I, unexpectedly and uniquely degraded Nef's major histocompatibility complex class I (MHC-I) downregulatory capacity, rendering the virus more vulnerable to CD8TL targeting other epitopes. These data aid in a mechanistic understanding of Nef functions and suggest means of immunity-mediated control of lentivirus replication. PMID:26637459

  3. Mechanistic understanding and significance of small peptides interaction with MHC class II molecules for therapeutic applications.

    PubMed

    Afridi, Saifullah; Hoessli, Daniel C; Hameed, Muhammad Waqar

    2016-07-01

    Major histocompatibility complex (MHC) class II molecules are expressed by antigen-presenting cells and stimulate CD4(+) T cells, which initiate humoral immune responses. Over the past decade, interest has developed to therapeutically impact the peptides to be exposed to CD4(+) T cells. Structurally diverse small molecules have been discovered that act on the endogenous peptide exchanger HLA-DM by different mechanisms. Exogenously delivered peptides are highly susceptible to proteolytic cleavage in vivo; however, it is only when successfully incorporated into stable MHC II-peptide complexes that these peptides can induce an immune response. Many of the small molecules so far discovered have highlighted the molecular interactions mediating the formation of MHC II-peptide complexes. As potential drugs, these small molecules open new therapeutic approaches to modulate MHC II antigen presentation pathways and influence the quality and specificity of immune responses. This review briefly introduces how CD4(+) T cells recognize antigen when displayed by MHC class II molecules, as well as MHC class II-peptide-loading pathways, structural basis of peptide binding and stabilization of the peptide-MHC complexes. We discuss the concept of MHC-loading enhancers, how they could modulate immune responses and how these molecules have been identified. Finally, we suggest mechanisms whereby MHC-loading enhancers could act upon MHC class II molecules.

  4. Endoplasmic reticulum aminopeptidase 1 function and its pathogenic role in regulating innate and adaptive immunity in cancer and major histocompatibility complex class I-associated autoimmune diseases.

    PubMed

    Fruci, D; Romania, P; D'Alicandro, V; Locatelli, F

    2014-08-01

    Major histocompatibility complex (MHC) class I molecules present antigenic peptides on the cell surface to alert natural killer (NK) cells and CD8(+) T cells for the presence of abnormal intracellular events, such as virus infection or malignant transformation. The generation of antigenic peptides is a multistep process that ends with the trimming of N-terminal extensions in the endoplasmic reticulum (ER) by aminopeptidases ERAP1 and ERAP2. Recent studies have highlighted the potential role of ERAP1 in reprogramming the immunogenicity of tumor cells in order to elicit innate and adaptive antitumor immune responses, and in conferring susceptibility to autoimmune diseases in predisposed individuals. In this review, we will provide an overview of the current knowledge about the role of ERAP1 in MHC class I antigen processing and how its manipulation may constitute a promising tool for cancer immunotherapy and treatment of MHC class I-associated autoimmune diseases.

  5. The major histocompatibility complex of the rat,RT 1 : II. biochemical evidence for a complex genetic organization.

    PubMed

    Sporer, R; Black, G; Rigiero, C; Manson, L; Götze, D

    1978-12-01

    Recombinational analysis has shown that the rat MHC,RT1 is divided into two regions:RT1.A, which codes for class I (transplantation) antigens, andRT1.B, which controls the humoral immune response and proliferative response to allogeneic cells as well as the expression of class II (Ia) antigens. Serological and sequence studies suggest that there might be more than one antigen-coding locus within theRT1.A region. Results obtained by sequential immunoprecipitation reveal that both regions code for at least two gene products. By implication, theRT1 complex must therefore harbor at least four loci;RT1.A andD coding for class I glycoproteins (45,000 daltons); andRT1.B andE coding for class II (Ia) glycoproteins (35,000 and 28,000 daltons).

  6. New polymorphic microsatellite markers in the human MHC class II region.

    PubMed

    Matsuzaka, Y; Makino, S; Nakajima, K; Tomizawa, M; Oka, A; Kimura, M; Bahram, S; Tamiya, G; Inoko, H

    2000-12-01

    The human major histocompatibility complex (MHC) class II region spans approximately 1.1 Mb and presently contains over 30 functional genes Susceptibility loci to numerous diseases, mainly of autoimmune nature are known to map to the this region, as assessed by associations with particular HLA class II alleles. However, it has been difficult to precisely localize these susceptibility loci to a single gene, for example DQB1 or DRB1, due to the tight linkage disequilibrium observed in the HLA class II region. To facilitate disease mapping within this region, we have analyzed 2 to approximately 5 bases short tandem repeats (microsatellites) in this same region. A total of 494 microsatellites were identified from the genomic sequence of the HLA class II region. These consist of 158 di-, 65 tri-, 163 tetra-, and 108 pent-nucleotide repeats, out of which four were located within the coding sequence of expressed genes (Daxx, BING1, RXRB and COL11A2). Twenty-two repeats were selected as polymorphic markers due to their high (average) number of alleles (8.9) as well as their high polymorphic content value (PIC) (0.58). These novel polymorphic microsatellites will provide useful genetic markers in HLA-related research, such as genetic mapping of HLA class II-associated diseases, transplantation matching, population genetics, identification of recombination hot spots as well as linkage disequilibrium studies.

  7. 49 CFR 238.317 - Class II brake test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Class II brake test. 238.317 Section 238.317... Requirements for Tier I Passenger Equipment § 238.317 Class II brake test. (a) A Class II brake test shall be.... In these circumstances, a Class II brake test shall be performed prior to the train's departure...

  8. 49 CFR 238.317 - Class II brake test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Class II brake test. 238.317 Section 238.317... Requirements for Tier I Passenger Equipment § 238.317 Class II brake test. (a) A Class II brake test shall be.... In these circumstances, a Class II brake test shall be performed prior to the train's departure...

  9. 49 CFR 238.317 - Class II brake test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Class II brake test. 238.317 Section 238.317... Requirements for Tier I Passenger Equipment § 238.317 Class II brake test. (a) A Class II brake test shall be.... In these circumstances, a Class II brake test shall be performed prior to the train's departure...

  10. Molecular and biological interaction between major histocompatibility complex class I antigens and luteinizing hormone receptors or beta-adrenergic receptors triggers cellular response in mice.

    PubMed Central

    Solano, A R; Cremaschi, G; Sánchez, M L; Borda, E; Sterin-Borda, L; Podestá, E J

    1988-01-01

    Purified IgG from BALB/c mouse anti-C3H serum exerts positive inotropic and chronotropic effects in C3H mouse atria and induces testosterone synthesis in C3H mouse Leydig cells. The effect depends on IgG concentration and can be abolished by beta-adrenergic-receptor and luteinizing hormone-receptor antagonists. IgG interferes with the binding of dihydroalprenolol and luteinizing hormone. Monoclonal antibodies against major histocompatibility complex class I antigens were active on the Leydig cells of C3H and BALB/c mice. There was a parallelism between the effect of each individual monoclonal antibody with specificity for a particular haplotype and the response of the target cell from the strains carrying such haplotypes. These antibodies could precipitate the soluble luteinizing hormone-receptor complex. The results suggested that bound hormone triggers the association of major histocompatibility class I antigen with the receptor, thereby activating the respective target cells. PMID:2839829

  11. Major histocompatibility complex class I genes in murine fibrosarcoma IC9 are down regulated at the level of the chromatin structure.

    PubMed Central

    Maschek, U; Pülm, W; Segal, S; Hämmerling, G J

    1989-01-01

    The fibrosarcoma IC9 is deficient in the expression of the major histocompatibility complex class I genes Kb, Kk, and Dk and expresses only the Db molecule. Because class I deficiency may enable tumor cells to escape the immune response by cytotoxic T lymphocytes, we investigated why the class I genes are not expressed. Expression of the silent class I genes could not be induced, but all known DNA-binding factors specific for class I genes could be detected in nuclear extracts of IC9 cells. After cloning of the silent Kb gene from the IC9 cells and subsequent transfection of this cloned Kb gene into LTK- and IC9 cells, normal Kb antigens were expressed on the cell surface of both cell lines. Digestion of the chromatin of IC9 cells with micrococcal nuclease and DNase I showed a decreased nuclease sensitivity of the silent class I genes in comparison with active genes and the absence of DNase I hypersensitive sites in the promoter region of the silent Dk gene. These findings demonstrate that class I expression is turned off by a cis-acting regulatory mechanism at the level of the chromatin structure. Images PMID:2506438

  12. Disequilibrium patterns of the peptide transporter loci within the HLA class II region

    SciTech Connect

    Klitz, W.; Stephens, C.J.; Carrington, M.

    1994-09-01

    Disequilibrium between genetic markers is expected to decline monotonically with recombinational map distance. We present evidence from the HLA class II region which seems to violate this principle. Pairwise disequilibrium values from a sample of northern Europeans were calculated for six loci ranging in physical separation from 7 kb to 550 kb. The histocompatibility loci DRB1, DQA1 and DQB1 located on the distal end of the class II region behave as a single evolutionary unit within which extremely high linkage disequilibrium exists. Lower but significant levels of disequilibrium are present between these loci and DPB1 located at the proximal edge of the HLA complex. The peptide transporter loci TAP1 and TAP2, located in the intervening region, reveal no disequilibrium with each other and low or negligible disequilibrium with the flanking loci. This evidence suggests either a high rate of gene conversion in the TAP loci which mixes TAP alleles among haplotypes while maintaining the flanking markers, or recombinational hot spots near and between the TAP loci operating in combination with selection to preserve particular combinations of alleles at the flanking histocompatibility loci. Whatever explanation proves correct, this work demonstrates that the lack of association of TAP alleles with a DR-DQ associated disease cannot be used as evidence for a centromeric boundary of influence on that disease.

  13. MHC class I and MHC class II DRB gene variability in wild and captive Bengal tigers (Panthera tigris tigris).

    PubMed

    Pokorny, Ina; Sharma, Reeta; Goyal, Surendra Prakash; Mishra, Sudanshu; Tiedemann, Ralph

    2010-10-01

    Bengal tigers are highly endangered and knowledge on adaptive genetic variation can be essential for efficient conservation and management. Here we present the first assessment of allelic variation in major histocompatibility complex (MHC) class I and MHC class II DRB genes for wild and captive tigers from India. We amplified, cloned, and sequenced alpha-1 and alpha-2 domain of MHC class I and beta-1 domain of MHC class II DRB genes in 16 tiger specimens of different geographic origin. We detected high variability in peptide-binding sites, presumably resulting from positive selection. Tigers exhibit a low number of MHC DRB alleles, similar to other endangered big cats. Our initial assessment-admittedly with limited geographic coverage and sample size-did not reveal significant differences between captive and wild tigers with regard to MHC variability. In addition, we successfully amplified MHC DRB alleles from scat samples. Our characterization of tiger MHC alleles forms a basis for further in-depth analyses of MHC variability in this illustrative threatened mammal.

  14. MHC class I and MHC class II DRB gene variability in wild and captive Bengal tigers (Panthera tigris tigris).

    PubMed

    Pokorny, Ina; Sharma, Reeta; Goyal, Surendra Prakash; Mishra, Sudanshu; Tiedemann, Ralph

    2010-10-01

    Bengal tigers are highly endangered and knowledge on adaptive genetic variation can be essential for efficient conservation and management. Here we present the first assessment of allelic variation in major histocompatibility complex (MHC) class I and MHC class II DRB genes for wild and captive tigers from India. We amplified, cloned, and sequenced alpha-1 and alpha-2 domain of MHC class I and beta-1 domain of MHC class II DRB genes in 16 tiger specimens of different geographic origin. We detected high variability in peptide-binding sites, presumably resulting from positive selection. Tigers exhibit a low number of MHC DRB alleles, similar to other endangered big cats. Our initial assessment-admittedly with limited geographic coverage and sample size-did not reveal significant differences between captive and wild tigers with regard to MHC variability. In addition, we successfully amplified MHC DRB alleles from scat samples. Our characterization of tiger MHC alleles forms a basis for further in-depth analyses of MHC variability in this illustrative threatened mammal. PMID:20821315

  15. Molecular polymorphism and expression analysis of MHC class II B gene from red sea bream (Chrysophrys major).

    PubMed

    Chen, Song-Lin; Zhang, Yu-Xi; Xu, Mei-Yu; Ji, Xiang-Shan; Yu, Guo-Cai; Dong, Cheng-Fang

    2006-01-01

    MHC class II (major histocompatibility complex class II) plays an important role in the immune response of vertebrates. Its function is to present antigenic peptides to the T-cell receptor. In order to study the function and molecular polymorphism of class II B gene in fish, we have isolated cDNAs encoding class II B from spleen cDNA library of red sea bream (Chrysophrys major) by using EST sequencing, and examined genomic organization, molecular polymorphism and expression of red sea bream class II B gene. As in other vertebrates, five exons and four introns were identified in red sea bream class II B gene. Seven class II B alleles were identified from seven individuals of red sea bream. The deduced amino acid sequence of red sea bream MHC class II B 1(Chma-DAB*0101) had 87.1, 85.1, 87.1, 90.4, 87.1, 90.8% identity with those of red sea bream class II B 2, 3, 4, 5, 6, 7(Chma-DAB*0201-Chma-DAB*0701), respectively, and had 75.2, 74.5, 55.9, 55.1, 34.3 and 30.4% identity with those of striped sea bass, cichlid, rainbow trout, Atlantic salmon, mouse and human, respectively. Four different class II B alleles were observed in a single individual and two different 3' untranslated region (3' UTR) sequences from this individual may infer the existence of two loci at least. Semi-quantitative RT-PCR demonstrated that high expression was detected in liver, head kidney, kidney, intestine, gill, stomach, hear and spleen, low expression in muscle and blood. Challenge of red sea bream with the pathogenic bacteria, Vibrio anguillarum, resulted in a significant decrease in the expression of MHC class II B mRNA from 5 to 72 h after infection in liver, spleen, head kidney and intestine, followed by a recovery to normal level after 96 h.

  16. Evidence for multiple MHC class II β loci in New Zealand's critically endangered kakapo, Strigops habroptilus.

    PubMed

    Knafler, Gabrielle J; Fidler, Andrew; Jamieson, Ian G; Robertson, Bruce C

    2014-02-01

    Immunologically important genes of the major histocompatibility complex (MHC) have been characterized in a number of avian species with the general finding of considerable variation in size and structural organization among organisms. A range of nonpasserines which represent early-diverging Neoave lineages have been described as having only one MHC class II β locus potentially leading to the conclusion that this is the ancestral condition. Here, we examine the monotypic, early-diverging, critically endangered kakapo, Strigops habroptilus, for allelic variation at MHC class II β exon 2, as part of species' recovery efforts. We found two to four confirmed sequence variants per individual indicating the presence of more than one MHC class II β locus. Given the kakapo's basal evolutionary status, evidence for multiple MHC class II β loci seems to counter the proposed mono-locus history of modern birds. However, MHC gene duplication, maintenance, and loss among and within bird species may confound avian relationships making it difficult to elucidate the ancestral state. This study adds essential data for disentangling the course of MHC structural evolution in birds.

  17. MHC class II molecules, cathepsins, and La/SSB proteins in lacrimal acinar cell endomembranes.

    PubMed

    Yang, T; Zeng, H; Zhang, J; Okamoto, C T; Warren, D W; Wood, R L; Bachmann, M; Mircheff, A K

    1999-11-01

    Sjögren's syndrome is a chronic autoimmune disease affecting the lacrimal glands and other epithelia. It has been suggested that acinar cells of the lacrimal glands provoke local autoimmune responses, leading to Sjögren's syndrome when they begin expressing major histocompatibility complex (MHC) class II molecules. We used isopycnic centrifugation and phase partitioning to resolve compartments that participate in traffic between the basolateral membranes and the endomembrane system to test the hypothesis that MHC class II molecules enter compartments that contain potential autoantigens, i.e., La/SSB, and enzymes capable of proteolytically processing autoantigen, i.e., cathepsins B and D. A series of compartments identified as secretory vesicle membranes, prelysosomes, and microdomains of the trans-Golgi network involved in traffic to the basolateral membrane, to the secretory vesicles, and to the prelysosomes were all prominent loci of MHC class II molecules, La/SSB, and cathepsins B and D. These observations support the thesis that lacrimal gland acinar cells that have been induced to express MHC class II molecules function as autoantigen processing and presenting cells.

  18. Association of Major Histocompatibility Complex Class 1 Chain-Related Gene A Dimorphism with Type 1 Diabetes and Latent Autoimmune Diabetes in Adults in the Algerian Population

    PubMed Central

    Belanteur, Khadidja; Amroun, Habiba; Benyahia, Amel; Heniche, Amel; Azzouz, Malha; Mimouni, Safia; Gervais, Thibaud; Latinne, Dominique; Boudiba, Aissa; Attal, Nabila; Abbadi, Mohamed Cherif

    2012-01-01

    Major histocompatibility complex class I chain-related gene A (MICA-129) dimorphism was investigated in 73 autoimmune diabetes patients (type 1 diabetes and latent autoimmune diabetes in adults) and 75 controls from Algeria. Only MICA-129 Val allele and MICA-129 Val/Val genotype frequencies were higher among patients than in the control group. Statistical analysis of the estimated extended HLA-DR-DQ-MICA haplotypes shown that individual effects of MICA alleles on HLA-DQ2-DR3-MICA-129 Val/Val and HLA-DQ8-DR4-MICA-129 Val/Val haplotypes were significantly higher in patients than in the control groups. These preliminary data might suggest a relevant role of MICA-129 Val/Val single nucleotide polymorphism (weak/weak binders of NKG2D receptor) in the pathogenesis of T1D and LADA. PMID:22323559

  19. Gene Conversion in the Evolution of Both the H-2 and Qa Class I Genes of the Murine Major Histocompatibility Complex

    PubMed Central

    Kuhner, M.; Watts, S.; Klitz, W.; Thomson, G.; Goodenow, R. S.

    1990-01-01

    In order to better understand the role of gene conversion in the evolution of the class I gene family of the major histocompatibility complex (MHC), we have used a computer algorithm to detect clustered sequence similarities among 24 class I DNA sequences from the H-2, Qa, and Tla regions of the murine MHC. Thirty-four statistically significant clusters were detected; individual analysis of the clusters suggested at least 25 past gene conversion or recombination events. These clusters are comparable in size to the conversions observed in the spontaneously occurring H-2K(bm) and H-2K(km2) mutations, and are distributed throughout all exons of the class I gene. Thus, gene conversion does not appear to be restricted to the regions of the class I gene encoding their antigen-presentation function. Moreover, both the highly polymorphic H-2 loci and the relatively monomorphic Qa and Tla loci appear to have participated as donors and recipients in conversion events. If gene conversion is not limited to the highly polymorphic loci of the MHC, then another factor, presumably natural selection, must be responsible for maintaining the observed differences in level of variation. PMID:2076814

  20. MHC class II-assortative mate choice in European badgers (Meles meles).

    PubMed

    Sin, Yung Wa; Annavi, Geetha; Newman, Chris; Buesching, Christina; Burke, Terry; Macdonald, David W; Dugdale, Hannah L

    2015-06-01

    The major histocompatibility complex (MHC) plays a crucial role in the immune system, and in some species, it is a target by which individuals choose mates to optimize the fitness of their offspring, potentially mediated by olfactory cues. Under the genetic compatibility hypothesis, individuals are predicted to choose mates with compatible MHC alleles, to increase the fitness of their offspring. Studies of MHC-based mate choice in wild mammals are under-represented currently, and few investigate more than one class of MHC genes. We investigated mate choice based on the compatibility of MHC class I and II genes in a wild population of European badgers (Meles meles). We also investigated mate choice based on microsatellite-derived pairwise relatedness, to attempt to distinguish MHC-specific effects from genomewide effects. We found MHC-assortative mating, based on MHC class II, but not class I genes. Parent pairs had smaller MHC class II DRB amino acid distances and smaller functional distances than expected from random pairings. When we separated the analyses into within-group and neighbouring-group parent pairs, only neighbouring-group pairs showed MHC-assortative mating, due to similarity at MHC class II loci. Our randomizations showed no evidence of genomewide-based inbreeding, based on 35 microsatellite loci; MHC class II similarity was therefore the apparent target of mate choice. We propose that MHC-assortative mate choice may be a local adaptation to endemic pathogens, and this assortative mate choice may have contributed to the low MHC genetic diversity in this population. PMID:25913367

  1. MHC class II-assortative mate choice in European badgers (Meles meles).

    PubMed

    Sin, Yung Wa; Annavi, Geetha; Newman, Chris; Buesching, Christina; Burke, Terry; Macdonald, David W; Dugdale, Hannah L

    2015-06-01

    The major histocompatibility complex (MHC) plays a crucial role in the immune system, and in some species, it is a target by which individuals choose mates to optimize the fitness of their offspring, potentially mediated by olfactory cues. Under the genetic compatibility hypothesis, individuals are predicted to choose mates with compatible MHC alleles, to increase the fitness of their offspring. Studies of MHC-based mate choice in wild mammals are under-represented currently, and few investigate more than one class of MHC genes. We investigated mate choice based on the compatibility of MHC class I and II genes in a wild population of European badgers (Meles meles). We also investigated mate choice based on microsatellite-derived pairwise relatedness, to attempt to distinguish MHC-specific effects from genomewide effects. We found MHC-assortative mating, based on MHC class II, but not class I genes. Parent pairs had smaller MHC class II DRB amino acid distances and smaller functional distances than expected from random pairings. When we separated the analyses into within-group and neighbouring-group parent pairs, only neighbouring-group pairs showed MHC-assortative mating, due to similarity at MHC class II loci. Our randomizations showed no evidence of genomewide-based inbreeding, based on 35 microsatellite loci; MHC class II similarity was therefore the apparent target of mate choice. We propose that MHC-assortative mate choice may be a local adaptation to endemic pathogens, and this assortative mate choice may have contributed to the low MHC genetic diversity in this population.

  2. Adenosine signaling inhibits CIITA-mediated MHC class II transactivation in lung fibroblast cells.

    PubMed

    Fang, Mingming; Xia, Jun; Wu, Xiaoyan; Kong, Hui; Wang, Hong; Xie, Weiping; Xu, Yong

    2013-08-01

    Efficient antigen presentation by major histocompatibility complex (MHC) molecules represents a critical process in adaptive immunity. Class II transactivator (CIITA) is considered the master regulator of MHC class II (MHC II) transcription. Previously, we have shown that CIITA expression is upregulated in smooth muscle cells deficient in A2b adenosine receptor. Here, we report that treatment with the adenosine receptor agonist adenosine-5'N-ethylcarboxamide (NECA) attenuated MHC II transcription in lung fibro-blast cells as a result of CIITA repression. Further analysis revealed that NECA preferentially abrogated CIITA transcription through promoters III and IV. Blockade with a selective A2b receptor antagonist MRS-1754 restored CIITA-dependent MHC II transactivation. Forskolin, an adenylyl cyclase activator, achieved the same effect as NECA. A2b signaling repressed CIITA transcription by altering histone modifications and recruitment of key factors on the CIITA promoters in a STAT1-dependent manner. MRS-1754 blocked the antagonism of transforming growth factor beta (TGF-β) in CIITA induction by interferon gamma (IFN-γ), alluding to a potential dialogue between TGF-β and adenosine signaling pathways. Finally, A2b signaling attenuated STAT1 phosphorylation and stimulated TGF-β synthesis. In conclusion, we have identified an adenosine-A2b receptor-adenylyl cyclase axis that influences CIITA-mediated MHC II transactivation in lung fibroblast cells and as such have provided invaluable insights into the development of novel immune-modulatory strategies.

  3. T cell receptor genes in a series of class I major histocompatibility complex-restricted cytotoxic T lymphocyte clones specific for a Plasmodium berghei nonapeptide: implications for T cell allelic exclusion and antigen-specific repertoire

    PubMed Central

    1991-01-01

    We report here the first extensive study of a T cell repertoire for a class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocyte (CTL) response. We have found that the T cell receptors (TCRs) carried by 28 H-2Kd-restricted CTL clones specific for a single Plasmodium berghei circumsporozoite nonapeptide are highly diverse in terms of V alpha, J alpha, and J beta segments and aminoacid composition of the junctional regions. However, despite this extensive diversity, a high proportion of the TCRs contain the same V beta segment. These results are in contrast to most previously reported T cell responses towards class II MHC-peptide complexes, where the TCR repertoires appeared to be much more limited. In our study, the finding of a dominant V beta in the midst of otherwise highly diverse TCRs suggests the importance of the V beta segment in shaping the T cell repertoire specific for a given MHC-peptide complex. As an additional finding, we observed that nearly all clones have rearranged both TCR alpha loci. Moreover, as many as one-third of the CTL clones that we analyzed apparently display two productive alpha rearrangements. This argues against a regulated model of sequential recombination at the alpha locus and consequently raises the question of whether allelic exclusion of the TCR alpha chain is achieved at all. PMID:1836010

  4. 46 CFR 50.30-15 - Class II pressure vessels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Class II pressure vessels. 50.30-15 Section 50.30-15... Fabrication Inspection § 50.30-15 Class II pressure vessels. (a) Class II pressure vessels shall be subject to... pressure vessels shall be performed during the welding of the longitudinal joint. At this time the...

  5. 46 CFR 50.30-15 - Class II pressure vessels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Class II pressure vessels. 50.30-15 Section 50.30-15... Fabrication Inspection § 50.30-15 Class II pressure vessels. (a) Class II pressure vessels shall be subject to... pressure vessels shall be performed during the welding of the longitudinal joint. At this time the...

  6. 46 CFR 50.30-15 - Class II pressure vessels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Class II pressure vessels. 50.30-15 Section 50.30-15... Fabrication Inspection § 50.30-15 Class II pressure vessels. (a) Class II pressure vessels shall be subject to... pressure vessels shall be performed during the welding of the longitudinal joint. At this time the...

  7. 46 CFR 50.30-15 - Class II pressure vessels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Class II pressure vessels. 50.30-15 Section 50.30-15... Fabrication Inspection § 50.30-15 Class II pressure vessels. (a) Class II pressure vessels shall be subject to... pressure vessels shall be performed during the welding of the longitudinal joint. At this time the...

  8. 46 CFR 50.30-15 - Class II pressure vessels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Class II pressure vessels. 50.30-15 Section 50.30-15... Fabrication Inspection § 50.30-15 Class II pressure vessels. (a) Class II pressure vessels shall be subject to... pressure vessels shall be performed during the welding of the longitudinal joint. At this time the...

  9. 78 FR 37114 - Self-Regulation of Class II Gaming

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ... the issuance of a certificate for tribal self-regulation of Class II gaming. 78 FR 20236, April 4... concerning the issuance of certificates for tribal self-regulation of Class II gaming: To correct a section... National Indian Gaming Commission 25 CFR Part 518 RIN 3141-AA44 Self-Regulation of Class II Gaming...

  10. The CD8+ T cell repertoire in beta 2-microglobulin-deficient mice is biased towards reactivity against self-major histocompatibility class I

    PubMed Central

    1994-01-01

    Beta 2-Microglobulin-deficient (beta 2m -/-) mice are reported to lack cell surface expression of major histocompatibility complex (MHC) class I molecules, CD8+ T cells, and the ability to mount MHC class I- specific T cell responses. We have observed that beta 2m -/- mice possess CD8+ T cells that can be induced to perform strong allospecific cytotoxic responses against nonself-MHC class I by in vivo priming. We report that these beta 2m -/- cytotoxic T lymphocyte (CTL) differ from those induced in beta 2m-positive littermates in that they cross-react and kill cells expressing self-MHC class I at normal ligand density with beta 2m. beta 2m -/- CTL could even be induced in primary mixed lymphocyte culture by self-MHC class I expressing stimulator cells, whereas allogeneic stimulator cells failed to elicit a response under similar conditions. Cells with a reduced cell surface MHC class I expression were less sensitive, while syngeneic beta 2m -/- cells were resistant to the beta 2m -/- CTL. This antiself-MHC reactivity could not be induced when beta 2m -/- T cells matured in an environment with normal MHC class I expression in bone marrow chimeric mice. Antiself- MHC reactivity was also observed against human peptide loading- deficient cells expressing the appropriate murine class I molecules, suggesting that affinity to self-MHC class I may occur irrespective of peptide content. The results fit with a model where positive and negative selection of CD8+ T cells in beta 2m -/- mice is mediated by low levels of MHC class I free heavy chains. In this model, low ligand density on selecting cells leads to positive selection of rare T cells that bind to low levels of MHC class I free heavy chains, resulting in a very small peripheral CD8+ compartment. Due to low density of the selecting ligand, negative selection does not remove T cells recognizing beta 2m-positive cells expressing self-MHC class I at normal ligand density, which generates a T cell repertoire that would

  11. Transloading of tumor cells with foreign major histocompatibility complex class I peptide ligand: a novel general strategy for the generation of potent cancer vaccines.

    PubMed Central

    Schmidt, W; Steinlein, P; Buschle, M; Schweighoffer, T; Herbst, E; Mechtler, K; Kirlappos, H; Birnstiel, M L

    1996-01-01

    The major hurdle to be cleared in active immunotherapy of cancer is the poor immunogenicity of cancer cells. In previous attempts to overcome this problem, whole tumor cells have been used as vaccines, either admixed with adjuvant(s) or genetically engineered to express nonself proteins or immunomodulatory factors before application. We have developed a novel approach to generate an immunogeneic, highly effective vaccine: major histocompatibility complex (MHC) class I-positive cancer cells are administered together with MHC class I-matched peptide ligands of foreign, nonself origin, generated by a procedure we term transloading. Murine tumor lines of the H2-Kd or the H2-Db haplotype, melanoma M-3 and B16-F10, respectively, as well as colon carcinoma CT-26 (H2-Kd), were transloaded with MHC-matched influenza virus-derived peptides and applied as irradiated vaccines. Mice bearing a deposit of live M-3 melanoma cells were efficiently cured by this treatment. In the CT-26 colon carcinoma and the B16-F10 melanoma, high efficacies were obtained against tumor challenge, suggesting the universal applicability of this new type of vaccine. With foreign peptide ligands adapted to the requirements of a desired MHC class I haplotype, this concept may be used for the treatment of human cancers. Images Fig. 1 PMID:8790404

  12. Introduction of protein or DNA delivered via recombinant Salmonella typhimurium into the major histocompatibility complex class I presentation pathway of macrophages.

    PubMed

    Catic, A; Dietrich, G; Gentschev, I; Goebel, W; Kaufmann, S H; Hess, J

    1999-02-01

    Recombinant (r) Salmonella typhimurium aroA strains which display the hen egg ovalbumin OVA(257-264) peptide SIINFEKL in secreted form were constructed. In addition, attenuated rS. typhimurium pcDNA-OVA constructs harbouring a eukaryotic expression plasmid encoding complete OVA were used to introduce the immunodominant OVA(257-264) epitope into the major histocompatibility complex (MHC) class I presentation pathway. Both modes of antigen delivery (DNA and protein) by Salmonella vaccine carriers stimulated OVA(257-264)-specific CD8 T-cell hybridomas. An in vitro infection system was established that allowed both rSalmonella carrier devices to facilitate MHC class I delivery of OVA(257-264) by coexpression of listeriolysin (Hly) or by coinfection with rS. typhimurium Hlys (Hess J., Gentschev I., Miko D., Welzel M., Ladel C., Goebel W., Kaufmann S.H.E., Proc. Natl. Acad. Sci. USA 93 (1996) 1458-1463). Coexpression of Hly and coinfection with rS. typhimurium Hlys slightly improved MHC class I processing of OVA. Our data provide further evidence for the feasibility of attenuated, Hly-expressing rS. typhimurium carriers secreting heterologous antigens or harbouring heterologous DNA as effective vaccines for stimulating CD8 T cells in addition to CD4 T cells. PMID:10594975

  13. Introduction of protein or DNA delivered via recombinant Salmonella typhimurium into the major histocompatibility complex class I presentation pathway of macrophages.

    PubMed

    Catic, A; Dietrich, G; Gentschev, I; Goebel, W; Kaufmann, S H; Hess, J

    1999-02-01

    Recombinant (r) Salmonella typhimurium aroA strains which display the hen egg ovalbumin OVA(257-264) peptide SIINFEKL in secreted form were constructed. In addition, attenuated rS. typhimurium pcDNA-OVA constructs harbouring a eukaryotic expression plasmid encoding complete OVA were used to introduce the immunodominant OVA(257-264) epitope into the major histocompatibility complex (MHC) class I presentation pathway. Both modes of antigen delivery (DNA and protein) by Salmonella vaccine carriers stimulated OVA(257-264)-specific CD8 T-cell hybridomas. An in vitro infection system was established that allowed both rSalmonella carrier devices to facilitate MHC class I delivery of OVA(257-264) by coexpression of listeriolysin (Hly) or by coinfection with rS. typhimurium Hlys (Hess J., Gentschev I., Miko D., Welzel M., Ladel C., Goebel W., Kaufmann S.H.E., Proc. Natl. Acad. Sci. USA 93 (1996) 1458-1463). Coexpression of Hly and coinfection with rS. typhimurium Hlys slightly improved MHC class I processing of OVA. Our data provide further evidence for the feasibility of attenuated, Hly-expressing rS. typhimurium carriers secreting heterologous antigens or harbouring heterologous DNA as effective vaccines for stimulating CD8 T cells in addition to CD4 T cells.

  14. Respiratory Syncytial Virus Infection Upregulates NLRC5 and Major Histocompatibility Complex Class I Expression through RIG-I Induction in Airway Epithelial Cells

    PubMed Central

    Guo, Xuancheng; Liu, Taixiang; Shi, Hengfei; Wang, Jingjing; Ji, Ping; Wang, Hongwei; Hou, Yayi; Tan, Ren Xiang

    2015-01-01

    ABSTRACT Respiratory syncytial virus (RSV) is the leading cause of acute respiratory tract viral infection in infants, causing bronchiolitis and pneumonia. The host antiviral response to RSV acts via retinoic acid-inducible gene I (RIG-I). We show here that RSV infection upregulates major histocompatibility complex class I (MHC-I) expression through the induction of NLRC5, a NOD-like, CARD domain-containing intracellular protein that has recently been identified as a class I MHC transactivator (CITA). RSV infection of A549 cells promotes upregulation of NLRC5 via beta interferon (IFN-β) production, since the NLRC5-inducing activity in a conditioned medium from RSV-infected A549 cells was removed by antibody to IFN-β, but not by antibody to IFN-γ. RSV infection resulted in RIG-I upregulation and induction of NLRC5 and MHC-I. Suppression of RIG-I induction significantly blocked NLRC5, as well as MHC-I, upregulation and diminished IRF3 activation. Importantly, Vero cells deficient in interferon production still upregulated MHC-I following introduction of the RSV genome by infection or transfection, further supporting a key role for RIG-I. A model is therefore proposed in which the host upregulates MHC-I expression during RSV infection directly via the induction of RIG-I and NLRC5 expression. Since elevated expression of MHC-I molecules can sensitize host cells to T lymphocyte-mediated cytotoxicity or immunopathologic damage, the results have significant implications for the modification of immunity in RSV disease. IMPORTANCE Human respiratory syncytial virus (RSV) is the leading cause of bronchiolitis and pneumonia in infants and young children worldwide. Infection early in life is linked to persistent wheezing and allergic asthma in later life, possibly related to upregulation of major histocompatibility class I (MHC-I) on the cell surface, which facilitates cytotoxic T cell activation and antiviral immunity. Here, we show that RSV infection of lung epithelial

  15. Cohesin regulates MHC class II genes through interactions with MHC class II insulators.

    PubMed

    Majumder, Parimal; Boss, Jeremy M

    2011-10-15

    Cohesin is a multiprotein, ringed complex that is most well-known for its role in stabilizing the association of sister chromatids between S phase and M. More recently, cohesin was found to be associated with transcriptional insulators, elements that are associated with the organization of chromatin into regulatory domains. The human MHC class II (MHC-II) locus contains 10 intergenic elements, termed MHC-II insulators, which bind the transcriptional insulator protein CCCTC-binding factor. MHC-II insulators interact with each other, forming a base architecture of discrete loops and potential regulatory domains. When MHC-II genes are expressed, their proximal promoter regulatory regions reorganize to the foci established by the interacting MHC-II insulators. MHC-II insulators also bind cohesin, but the functional role of cohesin in regulating this system is not known. In this article, we show that the binding of cohesin to MHC-II insulators occurred irrespective of MHC-II expression but was required for optimal expression of the HLA-DR and HLA-DQ genes. In a DNA-dependent manner, cohesin subunits interacted with CCCTC-binding factor and the MHC-II-specific transcription factors regulatory factor X and CIITA. Intriguingly, cohesin subunits were important for DNA looping interactions between the HLA-DRA promoter region and a 5' MHC-II insulator but were not required for interactions between the MHC-II insulators themselves. This latter observation introduces cohesin as a regulator of MHC-II expression by initiating or stabilizing MHC-II promoter regulatory element interactions with the MHC-II insulator elements, events that are required for maximal MHC-II transcription.

  16. Class II Resin Composites: Restorative Options.

    PubMed

    Patel, Minesh; Mehta, Shamir B; Banerji, Subir

    2015-10-01

    Tooth-coloured, resin composite restorations are amongst the most frequently prescribed forms of dental restoration to manage defects in posterior teeth. The attainment of a desirable outcome when placing posterior resin composite restorations requires the clinician to have a good understanding of the benefits (as well as the limitations) posed by this material, together with a sound knowledge of placement technique. Numerous protocols and materials have evolved to assist the dental operator with this type of demanding posterior restoration. With the use of case examples, four techniques available are reported here. CPD/Clinical Relevance: This article explores varying techniques for the restoration of Class II cavities using resin composite.

  17. Introducing the Clark Class II restoration.

    PubMed

    Clark, David

    2007-10-01

    As we introduce the concepts summarized in this article to practicing dentists, they show a broad spectrum of responses from shock and disbelief to sheer exuberance. As these cavity shapes are implemented we will see a dramatic reduction in the rate of tooth fracturing. We also anticipate that these restorations will outlast the class II amalgams that have served so well in the past. This very brief article can only touch on the dramatic differences of this minimally traumatic and incredibly durable direct composite. A full instructional DVD together with a textbook and hands-on courses are available and recommended.

  18. Susceptibility to Theiler's virus-induced demyelinating disease correlates with astrocyte class II induction and antigen presentation.

    PubMed Central

    Borrow, P; Nash, A A

    1992-01-01

    Theiler's murine encephalomyelitis virus (TMEV) is a picornavirus which induces a chronic demyelinating disease of the central nervous system (CNS) in certain susceptible mouse strains. Demyelination has been shown to result from immunopathological responses mediated by CD4+, major histocompatibility complex (MHC) class II-restricted T cells. As little or no class II is expressed in the normal mouse CNS, the ability of astrocytes to express these proteins and present antigen to T cells from TMEV-infected mice was investigated here. It is shown that astrocytes are capable of presenting TMEV to virus-specific T cells in vitro, and that this ability is dependent on prior induction of MHC class II by interferon-gamma (IFN-gamma) treatment. Unlike other viruses such as murine hepatitis virus-JHM (a coronavirus) and measles, TMEV is not capable of inducing class II on astrocytes directly. There is a correlation between the ease of class II induction on astrocytes from different mouse strains by IFN-gamma and mouse strain susceptibility to TMEV-induced demyelinating disease. These results suggest that following viral infection and initial T-cell infiltration into the CNS, class II induction on astrocytes is a key step allowing local antigen presentation and amplification of immunopathological responses within the CNS and hence the development of demyelinating disease. PMID:1628891

  19. Susceptibility to Theiler's virus-induced demyelinating disease correlates with astrocyte class II induction and antigen presentation.

    PubMed

    Borrow, P; Nash, A A

    1992-05-01

    Theiler's murine encephalomyelitis virus (TMEV) is a picornavirus which induces a chronic demyelinating disease of the central nervous system (CNS) in certain susceptible mouse strains. Demyelination has been shown to result from immunopathological responses mediated by CD4+, major histocompatibility complex (MHC) class II-restricted T cells. As little or no class II is expressed in the normal mouse CNS, the ability of astrocytes to express these proteins and present antigen to T cells from TMEV-infected mice was investigated here. It is shown that astrocytes are capable of presenting TMEV to virus-specific T cells in vitro, and that this ability is dependent on prior induction of MHC class II by interferon-gamma (IFN-gamma) treatment. Unlike other viruses such as murine hepatitis virus-JHM (a coronavirus) and measles, TMEV is not capable of inducing class II on astrocytes directly. There is a correlation between the ease of class II induction on astrocytes from different mouse strains by IFN-gamma and mouse strain susceptibility to TMEV-induced demyelinating disease. These results suggest that following viral infection and initial T-cell infiltration into the CNS, class II induction on astrocytes is a key step allowing local antigen presentation and amplification of immunopathological responses within the CNS and hence the development of demyelinating disease.

  20. Promoter accessibility within the environment of the MHC is affected in class II-deficient combined immunodeficiency.

    PubMed Central

    Kara, C J; Glimcher, L H

    1993-01-01

    Class II-deficient combined immunodeficiency (CID) is a hereditary disease resulting in abrogation of transcription of the class II genes of the major histocompatibility complex, due to a defect in a trans-acting regulatory factor. Cell lines from certain CID patients lack factor binding at multiple sites in class II promoters in vivo. A mutation in one of the promoter binding proteins could explain this 'bare' phenotype only if these factors bind cooperatively or in a temporal hierarchy. Alternatively, the mutation could affect the configuration of the promoter within the MHC locus. Here, we provide evidence that the factor(s) defective in class II-deficient CID controls the accessibility of class II promoters within the environment of the MHC. The in vivo occupancy of wild type and mutated class II promoter constructs was examined in stable transfectants of normal and CID-derived cell lines. The CID promoter phenotype could not be reproduced in a normal cell line by eliminating binding at any one promoter element, suggesting that these factors bind independently, both spatially and temporally. In contrast, promoter occupancy was partially restored in two CID lines at a randomly integrated wild type promoter, implying that the promoter is inaccessible to factors in its native environment, but accessible when moved to another location in the genome. Images PMID:8428578

  1. Recognition of Major Histocompatibility Complex Antigens on Cultured Human Biliary Epithelial Cells by Alloreactive Lymphocytes

    PubMed Central

    Saidman, Susan L.; Duquesnoy, Rene J.; Zeevi, Adriana; Fung, John J.; Starzl, Thomas E.; Demetris, A. Jake

    2010-01-01

    We have developed an in vitro system to study the interactions between biliary epithelium and lymphocytes using cultured human biliary epithelial cells. No class II antigens were detected by immunoperoxidase staining of the normal biliary epithelial cells, but alloactivated lymphocyte culture supernatants were able to induce class II expression. The activity of the supernatants was blocked with an anti-γ-interferon monoclonal antibody. In addition, recombinant human γ-interferon alone induced the expression of class II antigens and increased the intensity of class I staining of cultured biliary epithelial cells. Biliary epithelial cell–induced proliferation of alloreactive T lymphocytes demonstrated that the major histocompatibility complex molecules carry functional lymphocyte-activating determinants. The recognition of major histocompatibility complex determinants was confirmed by monoclonal antibody–blocking studies and by stimulation of an alloreactive T-cell clone. However, the biliary epithelial cells were much less potent stimulators than arterial endothelial cells tested in the same assay system. PMID:1704868

  2. Coexpression of class I major histocompatibility antigen and viral RNA in central nervous system of mice infected with Theiler's virus: a model for multiple sclerosis.

    PubMed

    Lindsley, M D; Patick, A K; Prayoonwiwat, N; Rodriguez, M

    1992-09-01

    Chronic infection of susceptible strains of mice with Theiler's murine encephalomyelitis virus (TMEV) results in central nervous system (CNS) demyelination similar to multiple sclerosis. Demyelination induced by TMEV is mediated, in part, by class I-restricted CD8+ T lymphocytes. For these T cells to function, they must recognize virus-infected CNS targets in the presence of class I major histocompatibility complex (MHC) antigen. Therefore, we studied in vivo expression of class I MHC antigen and viral antigen-RNA in prototypic mouse strains that are susceptible (SJL/J) or resistant (C57BL/10SNJ) to TMEV-induced demyelination. In brains of resistant mice, viral antigen-RNA expression peaked on day 3 after infection and was effectively diminished by day 5 such that few virus-infected cells were ever detected in the spinal cord. In contrast, susceptible mice demonstrated delay in clearance of TMEV from the brain and a subsequent increase and persistence of viral antigen-RNA in the spinal cord for as long as 277 days. Viral infection resulted in "upregulation" of class I MHC expression in the CNS. Class I MHC antigens were expressed as early as 1 day after infection in the choroid plexus of both strains of mice before detection of viral antigen or inflammation. In resistant mice, class I MHC expression predominated in the gray matter of the brain and spinal cord on day 7 after infection but returned to undetectable levels by day 28. In susceptible mice, class I MHC expression in the CNS persisted and was intense in the white matter of the spinal cord throughout chronic infection and demyelination. No class I MHC expression was detected in the CNS of uninfected mice. Coexpression of viral RNA and class I MHC antigen was demonstrated in CNS cells by using simultaneous in situ hybridization and immunoperoxidase technique. These results support the hypothesis that a class I-restricted immune response directed against virus-infected cells may be important in the mechanism

  3. Beta 2-microglobulin is not required for cell surface expression of the murine class I histocompatibility antigen H-2Db or of a truncated H-2Db.

    PubMed

    Allen, H; Fraser, J; Flyer, D; Calvin, S; Flavell, R

    1986-10-01

    beta 2-Microglobulin (beta 2m) has been thought essential for transport of all major histocompatibility complex class I antigens to the cell surface. Here, we show that the mouse class I antigen H-2Db is expressed at the cell surface even when there is no beta 2m present within the cell. This was established by transfecting the H-2Db gene into the R1E cell line, which lacks beta 2m. The conformation of the Db antigen expressed by the R1E transfectant is very different from that of the native molecule. This Db antigen is not recognized by Db-allospecific and Db-restricted cytotoxic T lymphocytes or by most monoclonal antibodies to the native Db. We show further that a deletion construct of the Db gene, which consists of exon 1 linked to exons 4-8, expresses a truncated Db antigen lacking domains 1 and 2 [Db-(1 + 2)] at the cell surface after transfection into the R1E line. Previous biochemical and crystallographic data have indicated that domain 3 is associated with beta 2m; unexpectedly, Db-(1 + 2) does not associate with beta 2m when the mouse beta 2mb gene is transfected into the R1E transfectant expressing the truncated Db. This suggests that interactions with domains 1 and 2 are important for the paired association of domain 3 and beta 2m in the native Db antigen.

  4. Pulse-chase analysis for studies of MHC class II biosynthesis, maturation, and peptide loading

    PubMed Central

    Hou, Tieying; Rinderknecht, Cornelia H; Hadjinicolaou, Andreas V; Busch, Robert; Mellins, Elizabeth

    2014-01-01

    Pulse-chase analysis is a commonly used technique for studying the synthesis, processing and transport of proteins. Cultured cells expressing proteins of interest are allowed to take up radioactively labeled amino acids for a brief interval (“pulse”), during which all newly synthesized proteins incorporate the label. The cells are then returned to non-radioactive culture medium for various times (“chase”), during which proteins may undergo conformational changes, trafficking, or degradation. Proteins of interest are isolated (usually by immunoprecipitation) and resolved by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and the fate of radiolabeled molecules is examined by autoradiography. This chapter describes a pulse-chase protocol suitable for studies of major histocompatibility complex (MHC) class II biosynthesis and maturation. We discuss how results are affected by the recognition by certain anti-class II antibodies of distinct class II conformations associated with particular biosynthetic states. Our protocol can be adapted to follow the fate of many other endogenously synthesized proteins, including viral or transfected gene products, in cultured cells. PMID:23329504

  5. Contact sensitizers specifically increase MHC class II expression on murine immature dendritic cells.

    PubMed

    Herouet, C; Cottin, M; LeClaire, J; Enk, A; Rousset, F

    2000-01-01

    Contact sensitivity is a T-cell-mediated immune disease that can occur when low-molecular-weight chemicals penetrate the skin. In vivo topical application of chemical sensitizers results in morphological modification of Langerhans cells (LC). Moreover, within 18 h, LC increase their major histocompatibility complex (MHC) class II antigens expression and migrate to lymph nodes where they present the sensitizer to T lymphocytes. We wanted to determine if such an effect could also be observed in vitro. However, because of the high genetic diversity encountered in humans, assays were performed with dendritic cells (DC) obtained from a Balb/c mouse strain. The capacity of a strong sensitizer, DNBS (2,4-dinitrobenzene sulfonic acid), to modulate the phenotype of bone marrow-derived DC in vitro, was investigated. A specific and marked increase of MHC class II molecules expression was observed within 18 h. To eliminate the use of animals in sensitization studies, the XS52 DC line was tested at an immature stage. A 30-min contact with the strong sensitizers DNBS and oxazolone, or the moderate mercaptobenzothiazole, resulted in upregulation of MHC class II molecules expression, analyzed after 18-h incubation. This effect was not observed with irritants (dimethyl sulfoxide and sodium lauryl sulfate) nor with a neutral molecule (sodium chloride). These data suggested the possibility of developing an in vitro model for the identification of the sensitizing potential of chemicals, using a constant and non animal-consuming material.

  6. Autoantibody Profiles in Collagen Disease Patients with Interstitial Lung Disease (ILD): Antibodies to Major Histocompatibility Complex Class I-Related Chain A (MICA) as Markers of ILD

    PubMed Central

    Furukawa, Hiroshi; Oka, Shomi; Shimada, Kota; Masuo, Kiyoe; Nakajima, Fumiaki; Funano, Shunichi; Tanaka, Yuki; Komiya, Akiko; Fukui, Naoshi; Sawasaki, Tatsuya; Tadokoro, Kenji; Nose, Masato; Tsuchiya, Naoyuki; Tohma, Shigeto

    2015-01-01

    Interstitial lung disease (ILD) is frequently associated with collagen disease. It is then designated as collagen vascular disease-associated ILD (CVD-ILD), and influences patients’ prognosis. The prognosis of acute-onset diffuse ILD (AoDILD) occurring in patients with collagen disease is quite poor. Here, we report our investigation of auto-antibody (Ab) profiles to determine whether they may be useful in diagnosing CVD-ILD or AoDILD in collagen disease. Auto-Ab profiles were analyzed using the Lambda Array Beads Multi-Analyte System, granulocyte immunofluorescence test, Proto-Array Human Protein Microarray, AlphaScreen assay, and glutathione S-transferase capture enzyme-linked immunosorbent assay in 34 patients with rheumatoid arthritis (RA) with or without CVD-ILD and in 15 patients with collagen disease with AoDILD. The average anti-major histocompatibility complex class I-related chain A (MICA) Ab levels were higher in RA patients with CVD-ILD than in those without (P = 0.0013). The ratio of the average anti-MICA Ab level to the average anti-human leukocyte antigen class I Ab level (ie, MICA/Class I) was significantly higher in RA patients with CVD-ILD compared with those without (P = 4.47 × 10−5). To the best of our knowledge, this is the first report of auto-Ab profiles in CVD-ILD. The MICA/Class I ratio could be a better marker for diagnosing CVD-ILD than KL-6 (Krebs von den lungen-6). PMID:26327779

  7. Stable isotope tagging of epitopes: a highly selective strategy for the identification of major histocompatibility complex class I-associated peptides induced upon viral infection.

    PubMed

    Meiring, Hugo D; Soethout, Ernst C; Poelen, Martien C M; Mooibroek, Dennis; Hoogerbrugge, Ronald; Timmermans, Hans; Boog, Claire J; Heck, Albert J R; de Jong, Ad P J M; van Els, Cécile A C M

    2006-05-01

    Identification of peptides presented in major histocompatibility complex (MHC) class I molecules after viral infection is of strategic importance for vaccine development. Until recently, mass spectrometric identification of virus-induced peptides was based on comparative analysis of peptide pools isolated from uninfected and virus-infected cells. Here we report on a powerful strategy aiming at the rapid, unambiguous identification of naturally processed MHC class I-associated peptides, which are induced by viral infection. The methodology, stable isotope tagging of epitopes (SITE), is based on metabolic labeling of endogenously synthesized proteins during infection. This is accomplished by culturing virus-infected cells with stable isotope-labeled amino acids that are expected to be anchor residues (i.e. residues of the peptide that have amino acid side chains that bind into pockets lining the peptide-binding groove of the MHC class I molecule) for the human leukocyte antigen allele of interest. Subsequently these cells are mixed with an equal number of non-infected cells, which are cultured in normal medium. Finally peptides are acid-eluted from immunoprecipitated MHC molecules and subjected to two-dimensional nanoscale LC-MS analysis. Virus-induced peptides are identified through computer-assisted detection of characteristic, binomially distributed ratios of labeled and unlabeled molecules. Using this approach we identified novel measles virus and respiratory syncytial virus epitopes as well as infection-induced self-peptides in several cell types, showing that SITE is a unique and versatile method for unequivocal identification of disease-related MHC class I epitopes.

  8. Autoantibody Profiles in Collagen Disease Patients with Interstitial Lung Disease (ILD): Antibodies to Major Histocompatibility Complex Class I-Related Chain A (MICA) as Markers of ILD.

    PubMed

    Furukawa, Hiroshi; Oka, Shomi; Shimada, Kota; Masuo, Kiyoe; Nakajima, Fumiaki; Funano, Shunichi; Tanaka, Yuki; Komiya, Akiko; Fukui, Naoshi; Sawasaki, Tatsuya; Tadokoro, Kenji; Nose, Masato; Tsuchiya, Naoyuki; Tohma, Shigeto

    2015-01-01

    Interstitial lung disease (ILD) is frequently associated with collagen disease. It is then designated as collagen vascular disease-associated ILD (CVD-ILD), and influences patients' prognosis. The prognosis of acute-onset diffuse ILD (AoDILD) occurring in patients with collagen disease is quite poor. Here, we report our investigation of auto-antibody (Ab) profiles to determine whether they may be useful in diagnosing CVD-ILD or AoDILD in collagen disease. Auto-Ab profiles were analyzed using the Lambda Array Beads Multi-Analyte System, granulocyte immunofluorescence test, Proto-Array Human Protein Microarray, AlphaScreen assay, and glutathione S-transferase capture enzyme-linked immunosorbent assay in 34 patients with rheumatoid arthritis (RA) with or without CVD-ILD and in 15 patients with collagen disease with AoDILD. The average anti-major histocompatibility complex class I-related chain A (MICA) Ab levels were higher in RA patients with CVD-ILD than in those without (P = 0.0013). The ratio of the average anti-MICA Ab level to the average anti-human leukocyte antigen class I Ab level (ie, MICA/Class I) was significantly higher in RA patients with CVD-ILD compared with those without (P = 4.47 × 10(-5)). To the best of our knowledge, this is the first report of auto-Ab profiles in CVD-ILD. The MICA/Class I ratio could be a better marker for diagnosing CVD-ILD than KL-6 (Krebs von den lungen-6).

  9. Class II-antigen-negative patient and mutant B-cell lines represent at least three, and probably four, distinct genetic defects defined by complementation analysis.

    PubMed Central

    Bénichou, B; Strominger, J L

    1991-01-01

    Expression of class II major histocompatibility complex antigens in defective B-lymphoblastoid cell lines from patients with class II antigen deficiency and from in vitro mutants generated with the same phenotype was studied. By heterogenetic fusion experiments, at least three, and probably four, complementation groups were defined. Furthermore, clone 13 (a DR-, DP-, but DQ+ cell line) appeared to belong to the RJ2.2.5 complementation group, for which all other members are DR-, DP-, and also DQ-. Thus, it is hypothesized that the cell lines of this group lack the activity of a gene that can differentially regulate the DR/DP and the DQ promoters. Images PMID:1852002

  10. Susceptibility of amphibians to chytridiomycosis is associated with MHC class II conformation

    PubMed Central

    Bataille, Arnaud; Cashins, Scott D.; Grogan, Laura; Skerratt, Lee F.; Hunter, David; McFadden, Michael; Scheele, Benjamin; Brannelly, Laura A.; Macris, Amy; Harlow, Peter S.; Bell, Sara; Berger, Lee; Waldman, Bruce

    2015-01-01

    The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause precipitous population declines in its amphibian hosts. Responses of individuals to infection vary greatly with the capacity of their immune system to respond to the pathogen. We used a combination of comparative and experimental approaches to identify major histocompatibility complex class II (MHC-II) alleles encoding molecules that foster the survival of Bd-infected amphibians. We found that Bd-resistant amphibians across four continents share common amino acids in three binding pockets of the MHC-II antigen-binding groove. Moreover, strong signals of selection acting on these specific sites were evident among all species co-existing with the pathogen. In the laboratory, we experimentally inoculated Australian tree frogs with Bd to test how each binding pocket conformation influences disease resistance. Only the conformation of MHC-II pocket 9 of surviving subjects matched those of Bd-resistant species. This MHC-II conformation thus may determine amphibian resistance to Bd, although other MHC-II binding pockets also may contribute to resistance. Rescuing amphibian biodiversity will depend on our understanding of amphibian immune defence mechanisms against Bd. The identification of adaptive genetic markers for Bd resistance represents an important step forward towards that goal. PMID:25808889

  11. Susceptibility of amphibians to chytridiomycosis is associated with MHC class II conformation.

    PubMed

    Bataille, Arnaud; Cashins, Scott D; Grogan, Laura; Skerratt, Lee F; Hunter, David; McFadden, Michael; Scheele, Benjamin; Brannelly, Laura A; Macris, Amy; Harlow, Peter S; Bell, Sara; Berger, Lee; Waldman, Bruce

    2015-04-22

    The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause precipitous population declines in its amphibian hosts. Responses of individuals to infection vary greatly with the capacity of their immune system to respond to the pathogen. We used a combination of comparative and experimental approaches to identify major histocompatibility complex class II (MHC-II) alleles encoding molecules that foster the survival of Bd-infected amphibians. We found that Bd-resistant amphibians across four continents share common amino acids in three binding pockets of the MHC-II antigen-binding groove. Moreover, strong signals of selection acting on these specific sites were evident among all species co-existing with the pathogen. In the laboratory, we experimentally inoculated Australian tree frogs with Bd to test how each binding pocket conformation influences disease resistance. Only the conformation of MHC-II pocket 9 of surviving subjects matched those of Bd-resistant species. This MHC-II conformation thus may determine amphibian resistance to Bd, although other MHC-II binding pockets also may contribute to resistance. Rescuing amphibian biodiversity will depend on our understanding of amphibian immune defence mechanisms against Bd. The identification of adaptive genetic markers for Bd resistance represents an important step forward towards that goal. PMID:25808889

  12. Susceptibility of amphibians to chytridiomycosis is associated with MHC class II conformation.

    PubMed

    Bataille, Arnaud; Cashins, Scott D; Grogan, Laura; Skerratt, Lee F; Hunter, David; McFadden, Michael; Scheele, Benjamin; Brannelly, Laura A; Macris, Amy; Harlow, Peter S; Bell, Sara; Berger, Lee; Waldman, Bruce

    2015-04-22

    The pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd) can cause precipitous population declines in its amphibian hosts. Responses of individuals to infection vary greatly with the capacity of their immune system to respond to the pathogen. We used a combination of comparative and experimental approaches to identify major histocompatibility complex class II (MHC-II) alleles encoding molecules that foster the survival of Bd-infected amphibians. We found that Bd-resistant amphibians across four continents share common amino acids in three binding pockets of the MHC-II antigen-binding groove. Moreover, strong signals of selection acting on these specific sites were evident among all species co-existing with the pathogen. In the laboratory, we experimentally inoculated Australian tree frogs with Bd to test how each binding pocket conformation influences disease resistance. Only the conformation of MHC-II pocket 9 of surviving subjects matched those of Bd-resistant species. This MHC-II conformation thus may determine amphibian resistance to Bd, although other MHC-II binding pockets also may contribute to resistance. Rescuing amphibian biodiversity will depend on our understanding of amphibian immune defence mechanisms against Bd. The identification of adaptive genetic markers for Bd resistance represents an important step forward towards that goal.

  13. High-throughput engineering and analysis of peptide binding to class II MHC

    PubMed Central

    Jiang, Wei; Boder, Eric T.

    2010-01-01

    Class II major histocompatibility complex (MHC-II) proteins govern stimulation of adaptive immunity by presenting antigenic peptides to CD4+ T lymphocytes. Many allelic variants of MHC-II exist with implications in peptide presentation and immunity; thus, high-throughput experimental tools for rapid and quantitative analysis of peptide binding to MHC-II are needed. Here, we present an expression system wherein peptide and MHC-II are codisplayed on the surface of yeast in an intracellular association-dependent manner and assayed by flow cytometry. Accordingly, the relative binding of different peptides and/or MHC-II variants can be assayed by genetically manipulating either partner, enabling the application of directed evolution approaches for high-throughput characterization or engineering. We demonstrate the application of this tool to map the side-chain preference for peptides binding to HLA-DR1 and to evolve novel HLA-DR1 mutants with altered peptide-binding specificity. PMID:20622157

  14. Expressed MHC class II genes in sea otters (Enhydra lutris) from geographically disparate populations

    USGS Publications Warehouse

    Bowen, L.; Aldridge, B.M.; Miles, A.K.; Stott, J.L.

    2006-01-01

    The major histocompatibility complex (MHC) is central to maintaining the immunologic vigor of individuals and populations. Classical MHC class II genes were targeted for partial sequencing in sea otters (Enhydra lutris) from populations in California, Washington, and Alaska. Sequences derived from sea otter peripheral blood leukocyte mRNAs were similar to those classified as DQA, DQB, DRA, and DRB in other species. Comparisons of the derived amino acid compositions supported the classification of these as functional molecules from at least one DQA, DQB, and DRA locus and at least two DRB loci. While limited in scope, phylogenetic analysis of the DRB peptide-binding region suggested the possible existence of distinct clades demarcated by geographic region. These preliminary findings support the need for additional MHC gene sequencing and expansion to a comprehensive study targeting additional otters. ?? 2006 Blackwell Munksgaard.

  15. Influence of kinship and MHC class II genotype on visual traits in zebrafish larvae (Danio rerio).

    PubMed

    Hinz, Cornelia; Gebhardt, Katharina; Hartmann, Alexander K; Sigman, Lauren; Gerlach, Gabriele

    2012-01-01

    Kin recognition can drive kin selection and the evolution of social behaviour. In zebrafish (Danio rerio, Hamilton 1822), kin recognition is based on olfactory and visual imprinting processes. If larvae are exposed to visual and chemical cues of kin at day 5 and 6 post fertilization they will recognize kin throughout life, while exposure to non-kin fails to trigger any recognition. Chemical imprinting signals are transcribed by polymorphic genes of the major histocompatibility complex (MHC) code; however, the underlying mechanism for visual imprinting remains unclear. Here we provide evidence for the existence of family-specific differences in morphometry and pigmentation pattern of six day old zebrafish larvae. While rump, tail and body pigmentation were dependent on relatedness, iris pigmentation and morphometry were also influenced by MHC class II genotype. Our study revealed that the MHC not only influences the chemical signature of individuals, but also their visual appearance. PMID:23251449

  16. Characterization of major histocompatibility complex class I loci of the lark sparrow (Chondestes grammacus) and insights into avian MHC evolution.

    PubMed

    Lyons, Amanda C; Hoostal, Matthew J; Bouzat, Juan L

    2015-08-01

    The major histocompatibilty complex (MHC) has become increasingly important in the study of the immunocapabilities of non-model vertebrates due to its direct involvement in the immune response. The characterization of MHC class I loci in the lark sparrow (Chondestes grammacus) revealed multiple MHC class I loci with elevated genetic diversity at exon 3, evidence of differential selection between the peptide binding region (PBR) and non-PBR, and the presence of multiple pseudogenes with limited divergence. The minimum number of functional MHC class I loci was estimated at four. Sequence analysis revealed d N /d S ratios significantly less than one at non-PBR sites, indicative of negative selection, whereas PBR sites associated with antigen recognition showed ratios greater than 1 but non-significant. GenBank surveys and phylogenetic analyses of previously reported avian MHC class I sequences revealed variable signatures of evolutionary processes acting upon this gene family, including gene duplication and potential concerted evolution. An increase in the number of class I loci across species coincided with an increase in pseudogene prevalence, revealing the importance of gene duplication in the expansion of multigene families and the creation of pseudogenes.

  17. The major histocompatibility class I locus in Atlantic salmon (Salmo salar L.): polymorphism, linkage analysis and protein modelling.

    PubMed

    Grimholt, Unni; Drabløs, Finn; Jørgensen, Sven Martin; Høyheim, Bjørn; Stet, René J M

    2002-11-01

    A cDNA library screening using the conserved exon 4 of Atlantic salmon Mhc class I as probe provided the basis for a study on Mhc class I polymorphism in a breeding population. Twelve different alleles were identified in the 82 dams and sires studied. No individual expressed more than two alleles, which corresponded to the diploid segregation patterns of the polymorphic marker residing within the 3'-untranslated tail. Close linkage between the Sasa-UBA and Sasa-TAP2B loci strengthens the claim that Sasa-UBA is the major Mhc class I locus in Atlantic salmon. We found no evidence for a second expressed classical or non-classical Mhc class I locus in Atlantic salmon. A phylogenetic analysis of salmonid Mhc class I sequences showed domains conserved between rainbow trout, brown trout and Atlantic salmon. Evidence for shuffling of the alpha(1) domain was identified and lineages of the remaining alpha(2) through the cytoplasmic tail gene segment can be defined. The coding sequence of one allele was found associated with two different markers, suggesting recombination within the 3'-tail dinucleotide repeat itself. Protein modelling of several Sasa-UBA alleles shows distinct differences in their peptide binding domains and enables a further understanding of the functionality of the high polymorphism. PMID:12439620

  18. Closely Related Mycobacterial Strains Demonstrate Contrasting Levels of Efficacy as Antitumor Vaccines and Are Processed for Major Histocompatibility Complex Class I Presentation by Multiple Routes in Dendritic Cells

    PubMed Central

    Cheadle, Eleanor J.; O'Donnell, Dearbhaile; Selby, Peter J.; Jackson, Andrew M.

    2005-01-01

    Mycobacteria expressing recombinant antigens are already being developed as vaccines against both infections and tumors. Little is known about how dendritic cells might process such antigens. Two different mycobacterial species, the fast-growing Mycobacterium smegmatis and the slow-growing M. bovis M. bovis BCG, were engineered to express a model tumor antigen, the Kb-restricted dominant cytotoxic T-lymphocyte epitope OVA257-264. Recombinant M. bovis BCG but not recombinant M. smegmatis conferred protection to mice challenged with the B16-OVA tumor cell line. We went on to investigate whether the contrast in antitumor efficacy could be due to differences in how dendritic cells process antigen from the two mycobacterial strains for class I presentation. Both strains of mycobacteria caused phenotypic maturation of dendritic cells, but recombinant M. smegmatis infection led to a greater degree of dendritic cell maturation than recombinant M. bovis BCG infection. Antigen from recombinant M. smegmatis was processed and presented as OVA257-264 on Kb molecules by the dendritic cell line DC2.4 but not by bone marrow-derived dendritic cells (BMDC) or splenic dendritic cells. In contrast, antigen from recombinant M. bovis BCG was presented by all three dendritic cell types as long as the mycobacteria were viable. Such presentation was dependent on proteasome function and nascent major histocompatibility complex (MHC) class I molecules in DC2.4 cells but independent of the proteasome and transporter associated with antigen processings (TAP) in BMDC and splenic dendritic cells. These data demonstrate for the first time that antigen vectored by the slow-growing M. bovis BCG but not that vectored by fast-growing, readily destroyed M. smegmatis is processed and presented on MHC class I by in vitro-generated dendritic cells, which has implications for recombinant microbial vaccine development. PMID:15664917

  19. Cloning and modeling of CD8 beta in the amphibian ambystoma Mexicanum. Evolutionary conserved structures for interactions with major histocompatibility complex (MHC) class I molecules.

    PubMed

    Fellah, Julien S; Tuffèry, Pierre; Etchebest, Catherine; Guillet, Françoise; Bleux, Christian; Charlemagne, Jacques

    2002-04-17

    Mammalian and avian T-cells exhibit a large number of well characterized surface molecules associated with their maturation degree. Very little is known in comparison with T-cell differentiation in ectothermic vertebrates. This is mainly due to the lack of probes to identify T-cell subsets. We cloned and sequenced the first ectothermic CD8 beta DNA complementary to RNA from an amphibian species, the Mexican axolotl. The CD8 beta chain was 30-36% identical with its avian and mammalian homologues. The extracellular V-like domain contained the two typically conserved cysteines and was followed by a J-like sequence containing the canonical Phe-Gly-X-Gly stretch. The connecting peptide was much longer than in other species and contained potential O-glycosylation sites. The axolotl CD8 beta and major histocompatibility complex class I molecules were modeled using human HLA-A2/CD8 alphaalpha complex as template. The backbone conformation of axolotl CD8 beta matched well with the CD8 alpha-2 subunit of the human complex but significant structural differences were located in the CDR1, CDR2 and DE loops. Both axolotl and human class I showed large negative surface potential. The interacting area of the human CD8 alpha chain and of the corresponding region of axolotl CD8 beta had positive electrostatic potential compatible with complexation with the corresponding class I molecules. The presence of a CD8 beta homologue in an amphibian species implies that it was already present in the Devonian ancestor of amphibians and mammals, i.e. more than 400 million years ago. PMID:12034498

  20. Retinoids act as multistep modulators of the major histocompatibility class I presentation pathway and sensitize neuroblastomas to cytotoxic lymphocytes.

    PubMed

    Vertuani, Simona; De Geer, Anna; Levitsky, Victor; Kogner, Per; Kiessling, Rolf; Levitskaya, Jelena

    2003-11-15

    The current therapeutic modalities achieve low response rates in human neuroblastoma, a frequent extracranial malignancy of the early childhood. We have assessed the effect of retinoids, used presently for the treatment of neuroblastoma, on the discrete steps of the MHC class I processing machinery and susceptibility of neuroblastoma cells to CTL-mediated killing. We demonstrate that retinoic acid derivatives induce the expression of proteolytic and regulatory subunits of the immunoproteasome, increase the half-life of MHC class I complexes, and enhance the sensitivity of neuroblastoma cells to both MHC class I-restricted peptide-specific and HLA nonrestricted lysis by CTLs. Importantly, effects of retinoids on the MHC class I pathway appear to be independent of IFN-gamma and/or TNF-alpha as intermediate messengers. To our knowledge, this is the first demonstration of inflammation-unrelated biological molecules that induce systemic modulation of antigen presentation in nonprofessional antigen presenting cells. Our findings suggest that the application of retinoids and T cell-based immunotherapy may be an effective combination for the treatment of neuroblastoma.

  1. Transcription of non-classic major histocompatibility complex (MHC) class I in the bovine placenta throughout gestation and after Brucella abortus infection.

    PubMed

    Dos Santos, Larissa Sarmento; da Silva Mol, Juliana Pinto; de Macedo, Auricélio Alves; Silva, Ana Patrícia Carvalho; Dos Santos Ribeiro, Diego Luiz; Santos, Renato Lima; da Paixão, Tatiane Alves; de Carvalho Neta, Alcina Vieira

    2015-10-15

    Transcription of non-classical major histocompatibility complex class I (MHC-I) was assessed in the bovine placenta throughout gestation. Additionally, the effect of Brucella abortus infection on expression of non-classical MHC-I was also evaluated using a chorioallantoic membrane explant model of infection. The non-classical MHC-I genes MICB and NC3 had higher levels of transcription in the intercotyledonary region when compared to the placentome, which had higher levels of transcription at the second trimester of gestation. NC1 and classical MHC-I had very low levels of transcription throughout gestation. Trophoblastic cells of B. abortus-infected chorioallantoic membrane explants had an increase in transcription of non-classical MHC-I at 4h post infection. Therefore, this study provides an analysis of non-classical MHC-I transcription at different stages of gestation and different placental tissues, and during B. abortus infection. These findings provide additional knowledge on immune regulation in placental tissues, a known immune-privileged site.

  2. Interaction between the CD8 coreceptor and major histocompatibility complex class I stabilizes T cell receptor-antigen complexes at the cell surface.

    PubMed

    Wooldridge, Linda; van den Berg, Hugo A; Glick, Meir; Gostick, Emma; Laugel, Bruno; Hutchinson, Sarah L; Milicic, Anita; Brenchley, Jason M; Douek, Daniel C; Price, David A; Sewell, Andrew K

    2005-07-29

    The off-rate (k(off)) of the T cell receptor (TCR)/peptide-major histocompatibility complex class I (pMHCI) interaction, and hence its half-life, is the principal kinetic feature that determines the biological outcome of TCR ligation. However, it is unclear whether the CD8 coreceptor, which binds pMHCI at a distinct site, influences this parameter. Although biophysical studies with soluble proteins show that TCR and CD8 do not bind cooperatively to pMHCI, accumulating evidence suggests that TCR associates with CD8 on the T cell surface. Here, we titrated and quantified the contribution of CD8 to TCR/pMHCI dissociation in membrane-constrained interactions using a panel of engineered pMHCI mutants that retain faithful TCR interactions but exhibit a spectrum of affinities for CD8 of >1,000-fold. Data modeling generates a "stabilization factor" that preferentially increases the predicted TCR triggering rate for low affinity pMHCI ligands, thereby suggesting an important role for CD8 in the phenomenon of T cell cross-reactivity.

  3. Major histocompatibility complex class I chain related (MIC) A gene, TNFa microsatellite alleles and TNFB alleles in juvenile idiopathic arthritis patients from Latvia.

    PubMed

    Nikitina Zake, Liene; Cimdina, Ija; Rumba, Ingrida; Dabadghao, Preethi; Sanjeevi, Carani B

    2002-05-01

    In order to analyze involvement of major histocompatibility complex class I chain-related gene A (MICA) and tumor necrosis factor a (TNFa) microsatellite polymorphisms as well as TNFB gene in juvenile idiopathic arthritis (JIA), we studied 128 patients divided into groups according to clinical features [monoarthritis (n = 14), oligoarthritis (n = 58), polyarthritis (n = 50), and systemic (n = 6)], and 114 age- and sex-matched healthy controls from Latvia. DNA samples were amplified with specific primers and used for genotyping of MICA and TNFa microsatellite. Typing for a biallelic NcoI polymerase chain reaction RFLP polymorphism located at the first intron of TNFB gene was done as follows: restriction digests generated fragments of 555bp and 185bp for TNFB*1 allele, and 740bp for TNFB*2 allele. The results were compared between cases and controls. We found significant increase of MICA allele A4 (p = 0.009; odds ratio [OR] = 2.3) and allele TNFa2 (p = 0.0001; OR = 4.4) in patients compared with controls. The frequency of allele TNFa9 was significantly decreased (p = 0.0001; OR = 0.1) in patients with JIA. No significant differences of TNFB allele frequency were found. Our data suggest that MICA and TNFa microsatellite polymorphisms may be used as markers for determination of susceptibility and protection from JIA.

  4. Structural analysis of the human interferon gamma receptor: a small segment of the intracellular domain is specifically required for class I major histocompatibility complex antigen induction and antiviral activity.

    PubMed Central

    Cook, J R; Jung, V; Schwartz, B; Wang, P; Pestka, S

    1992-01-01

    Mutations of the human interferon gamma (IFN-gamma) receptor intracellular domain have permitted us to define a restricted region of that domain as necessary for both induction of class I major histocompatibility complex antigen by IFN-gamma and protection against encephalomyocarditis virus. This region consists of five amino acids (YDKPH), all of which are conserved in the human and murine receptors. Tyr-457 and His-461 are essential for activity. Approximately 80% of the amino acids of the intracellular domain of the receptor is not required for major histocompatibility complex class I antigen induction or for antiviral protection against encephalomyocarditis virus. The observation that there was no protection by IFN-gamma against vesiculostomatitis virus indicates that other factors, in addition to chromosome 21 accessory factor(s), are required to generate the full complement of transduction signals from the human IFN-gamma receptor. Images PMID:1454813

  5. The structure of the antigen-binding groove of major histocompatibility complex class I molecules determines specific selection of self-peptides.

    PubMed Central

    van Bleek, G M; Nathenson, S G

    1991-01-01

    We have examined the effect of diversity in the antigen-binding groove of the Kb, Db, Kbm1, and Kbm8 major histocompatibility complex (MHC) class I molecules on the set of self-peptides they present on the cell surface, by using a procedure we recently developed in our laboratory to isolate endogenously processed peptides bound to MHC class I molecules. We found that such naturally processed peptides are 7-10 amino acids long. A major motif of tyrosine and phenylalanine residues at positions three and five was found for peptides binding to Kb. The availability of Kb mutant molecules Kbm1 and Kbm8, each with localized clustered changes in the antigen-binding cleft, allowed us to probe the effect of such small alterations on peptide selection. We found that such changes in different regions in the antigen-binding groove exert an absolute effect by changing subsets of self-peptides bound to these MHC molecules. In the Kbm1 mutant, the binding of the characteristic major set of Kb-associated peptides with tyrosine at position three or both positions three and five is abrogated, although this MHC molecule still binds peptides with tyrosine at position seven; the latter peptides also bind to Kb. Kbm8 shares the major Tyr-3, Tyr-5 peptide set that binds to Kb but does not bind the peptides with tyrosine at position seven. Thus differences in binding selectivity in Kbm1 and Kbm8 appear to be the major determinant for the observed alterations in in vivo immune responses. PMID:1763019

  6. Heterogenous graft rejection pathways in class I major histocompatibility complex-disparate combinations and their differential susceptibility to immunomodulation induced by intravenous presensitization with relevant alloantigens

    PubMed Central

    1991-01-01

    The present study investigates the heterogeneity of graft rejection pathways in class I major histocompatibility complex (MHC)-disparate combinations and the susceptibility of each pathway to immunomodulation induced by intravenous presensitization with alloantigens. Depletion of CD8+ T cells was induced by repeated administration of anti-CD8 monoclonal antibody. CD8+ T cell-depleted mice failed to generate anti- allo class I MHC cytotoxic T cell (CTL) responses but exhibited anti- allo class I MHC T cell responses, such as mixed lymphocyte reaction (MLR)/IL-2 production, that were induced by CD4+ T cells. In contrast, donor-specific intravenous presensitization (DSP), as a model of donor- specific transfusion, induced almost complete elimination of CD4+ and CD8+ T cell-mediated MLR/IL-2 production, whereas this regimen did not affect the generation of CTL responses induced by DSP-resistant elements (CD8+ CTL precursors and CD4+ CTL helpers). Prolongation of skin graft survival was not induced by either of the above two regimens alone, but by the combination of these. Prolonged graft survival was obtained irrespective of whether the administration of anti-CD8 antibody capable of eliminating CTL was started before or after DSP. The combination of DSP with injection of anti-CD4 antibody also effectively prolonged graft survival. However, this was the case only when the injection of antibody was started before DSP, because such antibody administration was capable of inhibiting the generation of CTL responses by eliminating DSP-resistant CD4+ CTL helpers. These results indicate that (a) the graft rejection in class I-disparate combinations is induced by CD8+ CTL-involved and -independent pathways that are resistant and susceptible to DSP, respectively; (b) DSP contributes to, but is not sufficient for, the prolongation of graft survival; and (c) the suppression of graft rejection requires an additional treatment for reducing DSP-resistant CTL responses. The results are

  7. Composition of MHC class II-enriched lipid microdomains is modified during maturation of primary dendritic cells.

    PubMed

    Setterblad, Niclas; Roucard, Corinne; Bocaccio, Claire; Abastado, Jean-Pierre; Charron, Dominique; Mooney, Nuala

    2003-07-01

    Dendritic cells (DCs) are the most potent antigen presenting cells. Major histocompatibility complex (MHC) class II molecule expression changes with maturation; immature DCs concentrate MHC class II molecules intracellularly, whereas maturation increases surface expression of MHC class II and costimulatory molecules to optimize antigen presentation. Signal transduction via MHC class II molecules localized in lipid microdomains has been described in B lymphocytes and in the THP-1 monocyte cell line. We have characterized MHC class II molecules throughout human DC maturation with particular attention to their localization in lipid-rich microdomains. Only immature DCs expressed empty MHC class II molecules, and maturation increased the level of peptide-bound heterodimers. Ligand binding to surface human leukocyte antigen (HLA)-DR induced rapid internalization in immature DCs. The proportion of cell-surface detergent-insoluble glycosphingolipid-enriched microdomain-clustered HLA-DR was higher in immature DCs despite the higher surface expression of HLA-DR in mature DCs. Constituents of HLA-DR containing microdomains included the src kinase Lyn and the cytoskeletal protein tubulin in immature DCs. Maturation modified the composition of the HLA-DR-containing microdomains to include protein kinase C (PKC)-delta, Lyn, and the cytoskeletal protein actin, accompanied by the loss of tubulin. Signaling via HLA-DR redistributed HLA-DR and -DM and PKC-delta as well as enriching the actin content of mature DC microdomains. The increased expression of HLA-DR as a result of DC maturation was therefore accompanied by modification of the spatial organization of HLA-DR. Such regulation could contribute to the distinct responses induced by ligand binding to MHC class II molecules in immature versus mature DCs.

  8. 25 CFR 522.10 - Individually owned class II and class III gaming operations other than those operating on...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Individually owned class II and class III gaming... GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.10 Individually owned class II and class...

  9. 25 CFR 522.10 - Individually owned class II and class III gaming operations other than those operating on...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 2 2014-04-01 2014-04-01 false Individually owned class II and class III gaming... GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.10 Individually owned class II and class...

  10. 25 CFR 522.10 - Individually owned class II and class III gaming operations other than those operating on...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Individually owned class II and class III gaming... GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.10 Individually owned class II and class...

  11. 25 CFR 522.10 - Individually owned class II and class III gaming operations other than those operating on...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Individually owned class II and class III gaming... GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.10 Individually owned class II and class...

  12. 25 CFR 522.10 - Individually owned class II and class III gaming operations other than those operating on...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Individually owned class II and class III gaming... GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.10 Individually owned class II and class...

  13. The major histocompatibility complex of primates.

    PubMed

    Heise, E R; Cook, D J; Schepart, B S; Manning, C H; McMahan, M R; Chedid, M; Keever, C A

    1987-08-31

    The major histocompatibility complex (MHC) encodes cell surface glycoproteins that function in self-nonself recognition and in allograft rejection. Among primates, the MHC has been well defined only in the human; in the chimpanzee and in two species of macaque monkeys the MHC is less well characterized. Serologic, biochemical and genetic evidence indicates that the basic organization of the MHC linkage group has been phylogenetically conserved. However, the number of genes and their linear relationship on the chromosomes differ between species. Class I MHC loci encode molecules that are the most polymorphic genes known. These molecules are ubiquitous in their tissue distribution and typically are recognized together with nominal antigens by cytotoxic lymphocytes. Class II MHC loci constitute a smaller family of serotypes serving as restricting elements for regulatory T lymphocytes. The distribution of class II antigens is limited mainly to cell types serving immune functions, and their expression is subject to up and down modulation. Class III loci code for components C2, C4 and Factor B (Bf) of the complement system. Interspecies differences in the extent of polymorphism occur, but the significance of this finding in relation to fitness and natural selection is unclear. Detailed information on the structure and regulation of MHC gene expression will be required to understand fully the biologic role of the MHC and the evolutionary relationships between species. Meanwhile, MHC testing has numerous applications to biomedical research, especially in preclinical tissue and organ transplantation studies, the study of disease mechanisms, parentage determination and breeding colony management. In this review, the current status of MHC definition in nonhuman primates will be summarized. Special emphasis is placed on the CyLA system of M. fascicularis which is a major focus in our laboratory. A highly polymorphic cynomolgus MHC has been partially characterized and consists

  14. Class II correction with the Incognito lingual appliance.

    PubMed

    Lawson, Robert B

    2013-09-01

    The Incognito fully customized lingual appliance provides excellent torque control. This offers the potential for class II correction using inter-maxillary traction without the usual iatrogenic effects associated with their use. A case is presented showing the potential of these appliances in controlling torque and achieving full class II correction on a non-extraction basis.

  15. Rapid Evolution of Major Histocompatibility Complex Class I Genes in Primates Generates New Disease Alleles in Humans via Hitchhiking Diversity

    PubMed Central

    Shiina, Takashi; Ota, Masao; Shimizu, Sayoko; Katsuyama, Yoshihiko; Hashimoto, Nami; Takasu, Miwa; Anzai, Tatsuya; Kulski, Jerzy K.; Kikkawa, Eri; Naruse, Taeko; Kimura, Natsuki; Yanagiya, Kazuyo; Watanabe, Atsushi; Hosomichi, Kazuyoshi; Kohara, Sakae; Iwamoto, Chie; Umehara, Yumi; Meyer, Alice; Wanner, Valérie; Sano, Kazumi; Macquin, Cécile; Ikeo, Kazuho; Tokunaga, Katsushi; Gojobori, Takashi; Inoko, Hidetoshi; Bahram, Seiamak

    2006-01-01

    A plausible explanation for many MHC-linked diseases is lacking. Sequencing of the MHC class I region (coding units or full contigs) in several human and nonhuman primate haplotypes allowed an analysis of single nucleotide variations (SNV) across this entire segment. This diversity was not evenly distributed. It was rather concentrated within two gene-rich clusters. These were each centered, but importantly not limited to, the antigen-presenting HLA-A and HLA-B/-C loci. Rapid evolution of MHC-I alleles, as evidenced by an unusually high number of haplotype-specific (hs) and hypervariable (hv) (which could not be traced to a single species or haplotype) SNVs within the classical MHC-I, seems to have not only hitchhiked alleles within nearby genes, but also hitchhiked deleterious mutations in these same unrelated loci. The overrepresentation of a fraction of these hvSNV (hv1SNV) along with hsSNV, as compared to those that appear to have been maintained throughout primate evolution (trans-species diversity; tsSNV; included within hv2SNV) tends to establish that the majority of the MHC polymorphism is de novo (species specific). This is most likely reminiscent of the fact that these hsSNV and hv1SNV have been selected in adaptation to the constantly evolving microbial antigenic repertoire. PMID:16702430

  16. Efficiency of Class I and Class II malocclusion treatment with four premolar extractions

    PubMed Central

    JANSON, Guilherme; NAKAMURA, Alexandre; BARROS, Sérgio Estelita; BOMBONATTI, Roberto; CHIQUETO, Kelly

    2014-01-01

    Four premolar extractions is a successful protocol to treat Class I malocclusion, but it is a less efficient way when compared with other Class II treatment protocols. Objective: The objective of this study was to evaluate the influence of anteroposterior discrepancy on the success of four premolar extractions protocol. For that, treatment efficiency of Class I and complete Class II malocclusions, treated with four premolar extractions were compared. Methods: A sample of 107 records from 75 Class I (mean age of 13.98 years - group 1) and 32 Class II (mean age of 13.19 years - group 2) malocclusion patients treated with four premolar extractions was selected. The initial and final occlusal status of each patient was evaluated on dental casts with the PAR index. The treatment time was calculated based on the clinical charts, and the treatment efficiency was obtained by the ratio between the percentage of PAR reduction and treatment time. The PAR index and its components, the treatment time and the treatment efficiency of the groups were statistically compared with t tests and Mann-Whitney U-test. Results: The Class II malocclusion patients had a greater final PAR index than Class I malocclusion patients, and similar duration (Class I - 28.95 mo. and Class II - 28.10 mo.) and treatment efficiency. Conclusion: The treatment of the complete Class II malocclusion with four premolar extractions presented worse occlusal results than Class I malocclusion owing to incomplete molar relationship correction. PMID:24918660

  17. Characterization and 454 pyrosequencing of Major Histocompatibility Complex class I genes in the great tit reveal complexity in a passerine system

    PubMed Central

    2012-01-01

    Background The critical role of Major Histocompatibility Complex (Mhc) genes in disease resistance and their highly polymorphic nature make them exceptional candidates for studies investigating genetic effects on survival, mate choice and conservation. Species that harbor many Mhc loci and high allelic diversity are particularly intriguing as they are potentially under strong selection and studies of such species provide valuable information as to the mechanisms maintaining Mhc diversity. However comprehensive genotyping of complex multilocus systems has been a major challenge to date with the result that little is known about the consequences of this complexity in terms of fitness effects and disease resistance. Results In this study, we genotyped the Mhc class I exon 3 of the great tit (Parus major) from two nest-box breeding populations near Oxford, UK that have been monitored for decades. Characterization of Mhc class I exon 3 was adopted and bidirectional sequencing was carried using the 454 sequencing platform. Full analysis of sequences through a stepwise variant validation procedure allowed reliable typing of more than 800 great tits based on 214,357 reads; from duplicates we estimated the repeatability of typing as 0.94. A total of 862 alleles were detected, and the presence of at least 16 functional loci was shown - the highest number characterized in a wild bird species. Finally, the functional alleles were grouped into 17 supertypes based on their antigen binding affinities. Conclusions We found extreme complexity at the Mhc class I of the great tit both in terms of allelic diversity and gene number. The presence of many functional loci was shown, together with a pseudogene family and putatively non-functional alleles; there was clear evidence that functional alleles were under strong balancing selection. This study is the first step towards an in-depth analysis of this gene complex in this species, which will help understanding how parasite

  18. Immunotoxin Against a Donor MHC Class II Molecule Induces Indefinite Survival of Murine Kidney Allografts

    PubMed Central

    Brown, K.; Nowocin, A. K.; Meader, L.; Edwards, L. A.; Smith, R. A.

    2016-01-01

    Rejection of donor organs depends on the trafficking of donor passenger leukocytes to the secondary lymphoid organs of the recipient to elicit an immune response via the direct antigen presentation pathway. Therefore, the depletion of passenger leukocytes may be clinically applicable as a strategy to improve graft survival. Because major histocompatibility complex (MHC) class II+ cells are most efficient at inducing immune responses, selective depletion of this population from donor grafts may dampen the alloimmune response and prolong graft survival. In a fully MHC mismatched mouse kidney allograft model, we describe the synthesis of an immunotoxin, consisting of the F(ab′)2 fragment of a monoclonal antibody against the donor MHC class II molecule I‐Ak conjugated with the plant‐derived ribosomal inactivating protein gelonin. This anti–I‐Ak gelonin immunotoxin depletes I‐Ak expressing cells specifically in vitro and in vivo. When given to recipients of kidney allografts, it resulted in indefinite graft survival with normal graft function, presence of Foxp3+ cells within donor grafts, diminished donor‐specific antibody formation, and delayed rejection of subsequent donor‐type skin grafts. Strategies aimed at the donor arm of the immune system using agents such as immunotoxins may be a useful adjuvant to existing recipient‐orientated immunosuppression. PMID:26799449

  19. Antibody recognition of an immunogenic influenza hemagglutinin-human leukocyte antigen class II complex

    PubMed Central

    1991-01-01

    The A/Japan/57 influenza hemagglutin (HA) peptide HA 128-145, when bound by human histocompatibility leukocyte antigen-DRw11 cells, is recognized by the human CD4+ T cell clone V1. A rabbit antiserum has been raised against HA 128-145 which recognizes not only the free peptide, but also the HA 128-145/DRw11 complex on a solid matrix, in solution, or on the surface of viable cells. The detection of these complexes on viable cells was shown to be class II specific, DRw11 restricted, and commensurate with the level of DRw11 expression. The identity of DRw11 as the cell surface molecule binding HA 128-145 was confirmed by immunoprecipitation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and tryptic peptide mapping. Using this antiserum HA 128-145/DRw11 complexes could be detected on the cell surface as soon as 30 min after the peptide was added, and increased up to 24 h. Dissociation kinetics showed these complexes were long-lived, with a half-life of approximately 14 h. This anti-HA peptide antiserum represents the first direct means of studying antigenic peptide-human leukocyte antigen class II complexes on the surface of living cells without the addition of a non-amino acid moiety to the peptide. The properties of this antiserum thus provide the potential to study naturally processed antigenic peptides as well as the mechanism of processing itself in a physiologically relevant system. PMID:2056278

  20. Btn2a2, a T cell immunomodulatory molecule coregulated with MHC class II genes

    PubMed Central

    Sarter, Kerstin; Leimgruber, Elisa; Gobet, Florian; Agrawal, Vishal; Dunand-Sauthier, Isabelle; Barras, Emmanuèle; Mastelic-Gavillet, Béatris; Kamath, Arun; Fontannaz, Paola; Guéry, Leslie; Duraes, Fernanda do Valle; Lippens, Carla; Ravn, Ulla; Santiago-Raber, Marie-Laure; Magistrelli, Giovanni; Fischer, Nicolas; Siegrist, Claire-Anne; Hugues, Stéphanie

    2016-01-01

    Evidence has recently emerged that butyrophilins, which are members of the extended B7 family of co-stimulatory molecules, have diverse functions in the immune system. We found that the human and mouse genes encoding butyrophilin-2A2 (BTN2A2) are regulated by the class II trans-activator and regulatory factor X, two transcription factors dedicated to major histocompatibility complex class II expression, suggesting a role in T cell immunity. To address this, we generated Btn2a2-deficient mice. Btn2a2−/− mice exhibited enhanced effector CD4+ and CD8+ T cell responses, impaired CD4+ regulatory T cell induction, potentiated antitumor responses, and exacerbated experimental autoimmune encephalomyelitis. Altered immune responses were attributed to Btn2a2 deficiency in antigen-presenting cells rather than T cells or nonhematopoietic cells. These results provide the first genetic evidence that BTN2A2 is a co-inhibitory molecule that modulates T cell–mediated immunity. PMID:26809444

  1. The major histocompatibility complex in monotremes: an analysis of the evolution of Mhc class I genes across all three mammalian subclasses.

    PubMed

    Miska, Katarzyna B; Harrison, Gavan A; Hellman, Lars; Miller, Robert D

    2002-09-01

    We report the isolation and characterization of cDNA clones of expressed, functional major histocompatibility complex class-I ( Mhc-I) genes from two species of monotremes: the duck-billed platypus and the short-beaked echidna. The cDNA clones were isolated from libraries constructed from spleen RNA, clearly establishing their expression in at least this one peripheral lymphoid organ. From the presence of conserved amino acid residues, it appears the expressed sequences encode molecules that likely function as classical Mhc-I. These clones were isolated using monotreme Mhc-I processed pseudogenes as probes. These processed pseudogenes were isolated from genomic DNA and, based on their structure, are likely independently derived in the platypus and echidna. When all the monotreme sequences were included in phylogenetic analyses, we found no apparent orthologous relationships between the platypus and echidna Mhc-I. Analyses that included a large number of Mhc-I sequences from other taxa support a separate monotreme Mhc-I clade, basal to a therian Mhc-I clade that is comprised of sequences from marsupial and placental mammals. The phylogenies also support the hypothesis that Mhc-I genes of placental mammals, marsupials, and monotremes are derived from three separate lineages of Mhc-I genes, best explained by two rounds of duplications and deletions. The first round would have occurred prior to the divergence of monotremes and therians, and the second prior to the divergence of marsupials and placental mammals. The sequences described here represent the first reported functional monotreme Mhc-I, as well as the first processed pseudogenes of any type from monotremes.

  2. In silico prediction of peptide binding affinity to class I mouse major histocompatibility complexes: a comparative molecular similarity index analysis (CoMSIA) study.

    PubMed

    Hattotuwagama, Channa K; Doytchinova, Irini A; Flower, Darren R

    2005-01-01

    Current methods for the in silico identification of T cell epitopes (which form the basis of many vaccines, diagnostics, and reagents) rely on the accurate prediction of peptide-major histocompatibility complex (MHC) affinity. A three-dimensional quantitative structure-activity relationship (3D-QSAR) for the prediction of peptide binding to class I MHC molecules was established using the comparative molecular similarity index analysis (CoMSIA) method. Three MHC alleles were studied: H2-D(b), H2-K(b), and H2-K(k). Models were produced for each allele. Each model consisted of five physicochemical descriptors-steric bulk, electrostatic potentials, hydrophobic interactions, and hydrogen-bond donor and hydrogen-bond acceptor abilities. The models have an acceptable level of predictivity: cross-validation leave-one-out statistical terms q2 and SEP (standard error of prediction) ranged between 0.490 and 0.679 and between 0.525 and 0.889, respectively. The non-cross-validated statistical terms r2 and SEE (standard error of estimate) ranged between 0.913 and 0.979 and between 0.167 and 0.248, respectively. The use of coefficient contour maps, which indicate favored and disfavored areas for each position of the MHC-bound peptides, allowed the binding specificity of each allele to be identified, visualized, and understood. The present study demonstrates the effectiveness of CoMSIA as a method for studying peptide-MHC interactions. The peptides used in this study are available on the Internet (http://www.jenner.ac.uk/AntiJen). The partial least-squares method is available commercially in the SYBYL molecular modeling software package. PMID:16180918

  3. Us3 kinase encoded by herpes simplex virus 1 mediates downregulation of cell surface major histocompatibility complex class I and evasion of CD8+ T cells.

    PubMed

    Imai, Takahiko; Koyanagi, Naoto; Ogawa, Ryo; Shindo, Keiko; Suenaga, Tadahiro; Sato, Ayuko; Arii, Jun; Kato, Akihisa; Kiyono, Hiroshi; Arase, Hisashi; Kawaguchi, Yasushi

    2013-01-01

    Detection and elimination of virus-infected cells by CD8(+) cytotoxic T lymphocytes (CTLs) depends on recognition of virus-derived peptides presented by major histocompatibility complex class I (MHC-I) molecules on the surface of infected cells. In the present study, we showed that inactivation of the activity of viral kinase Us3 encoded by herpes simplex virus 1 (HSV-1), the etiologic agent of several human diseases and a member of the alphaherpesvirinae, significantly increased cell surface expression of MHC-I, thereby augmenting CTL recognition of infected cells in vitro. Overexpression of Us3 by itself had no effect on cell surface expression of MHC-I and Us3 was not able to phosphorylate MHC-I in vitro, suggesting that Us3 indirectly downregulated cell surface expression of MHC-I in infected cells. We also showed that inactivation of Us3 kinase activity induced significantly more HSV-1-specific CD8(+) T cells in mice. Interestingly, depletion of CD8(+) T cells in mice significantly increased replication of a recombinant virus encoding a kinase-dead mutant of Us3, but had no effect on replication of a recombinant virus in which the kinase-dead mutation was repaired. These results indicated that Us3 kinase activity is required for efficient downregulation of cell surface expression of MHC-I and mediates evasion of HSV-1-specific CD8(+) T cells. Our results also raised the possibility that evasion of HSV-1-specific CD8(+) T cells by HSV-1 Us3-mediated inhibition of MHC-I antigen presentation might in part contribute to viral replication in vivo.

  4. Prediction of peptides binding to MHC class I and II alleles by temporal motif mining

    PubMed Central

    2013-01-01

    Background MHC (Major Histocompatibility Complex) is a key player in the immune response of most vertebrates. The computational prediction of whether a given antigenic peptide will bind to a specific MHC allele is important in the development of vaccines for emerging pathogens, the creation of possibilities for controlling immune response, and for the applications of immunotherapy. One of the problems that make this computational prediction difficult is the detection of the binding core region in peptides, coupled with the presence of bulges and loops causing variations in the total sequence length. Most machine learning methods require the sequences to be of the same length to successfully discover the binding motifs, ignoring the length variance in both motif mining and prediction steps. In order to overcome this limitation, we propose the use of time-based motif mining methods that work position-independently. Results The prediction method was tested on a benchmark set of 28 different alleles for MHC class I and 27 different alleles for MHC class II. The obtained results are comparable to the state of the art methods for both MHC classes, surpassing the published results for some alleles. The average prediction AUC values are 0.897 for class I, and 0.858 for class II. Conclusions Temporal motif mining using partial periodic patterns can capture information about the sequences well enough to predict the binding of the peptides and is comparable to state of the art methods in the literature. Unlike neural networks or matrix based predictors, our proposed method does not depend on peptide length and can work with both short and long fragments. This advantage allows better use of the available training data and the prediction of peptides of uncommon lengths. PMID:23368521

  5. Class I and class II ribonuclease H activities in Crithidia fasciculata (Protozoa).

    PubMed

    Vonwirth, H; Köck, J; Büsen, W

    1991-01-15

    The protozoan Crithidia fasciculata contains two different ribonuclease H activities. These enzymes display similar physical and biochemical characteristics to their homologues in higher eukaryotes, for instance calf thymus class I and class II ribonuclease H. Class I ribonuclease H of lower and higher eukaryotes can be activated by Mg2(+)- and Mn2(+)-ions. However, the presence of Mn2(+)-ions is inhibitory for the Mg2(+)-dependent class II ribonuclease H activity of Crithidia fasciculata and calf thymus. The protozoan class I-homologue enzyme appears to be serologically related to the class I ribonuclease H of calf thymus.

  6. Linkage map of the human major histocompatibility complex including the tumor necrosis factor genes

    SciTech Connect

    Carroll, M.C.; Katzman, P.; Alicot, E.M.; Koller, B.H.; Geraghty, D.E.; Orr, H.T.; Strominger, J.L.; Spies, T.

    1987-12-01

    The tumor necrosis factor (TNF) ..cap alpha.. and ..beta.. gene pair has been linked in the human major histocompatibility complex to HLA-B, HLA-C, and, tentatively, HLA-E and HLA-A on one side and to the class III complement/steroid 21-hydroxylase gene cluster on the other by pulsed-field gel electrophoresis. The TNF genes are located 200 kilobases (kb) centromeric of HLA-B and about 350 kb telomeric of the class III cluster. Together with previous data on the linkage and structures of the class II and class III regions, a restriction map of the entire human major histocompatibility complex of about 3500 kb has been prepared.

  7. Equine Herpesvirus 1 Multiply Inserted Transmembrane Protein pUL43 Cooperates with pUL56 in Downregulation of Cell Surface Major Histocompatibility Complex Class I

    PubMed Central

    Huang, Teng; Ma, Guanggang

    2015-01-01

    ABSTRACT Herpesviruses have evolved an array of strategies to counteract antigen presentation by major histocompatibility complex class I (MHC-I). Previously, we identified pUL56 of equine herpesvirus 1 (EHV-1) as one major determinant of the downregulation of cell surface MHC-I (G. Ma, S. Feineis, N. Osterrieder, and G. R. Van de Walle, J. Virol. 86:3554–3563, 2012, http://dx.doi.org/10.1128/JVI.06994-11; T. Huang, M. J. Lehmann, A. Said, G. Ma, and N. Osterrieder, J. Virol. 88:12802–12815, 2014, http://dx.doi.org/10.1128/JVI.02079-14). Since pUL56 was able to exert its function only in the context of virus infection, we hypothesized that pUL56 cooperates with another viral protein. Here, we generated and screened a series of EHV-1 single-gene deletion mutants and found that the pUL43 orthologue was required for downregulation of cell surface MHC-I expression at the same time of infection as when pUL56 exerts its function. We demonstrate that the absence of pUL43 was not deleterious to virus growth and that expression of pUL43 was detectable from 2 h postinfection (p.i.) but decreased after 8 h p.i. due to lysosomal degradation. pUL43 localized within Golgi vesicles and required a unique hydrophilic N-terminal domain to function properly. Finally, coexpression of pUL43 and pUL56 in transfected cells reduced the cell surface expression of MHC-I. This process was dependent on PPxY motifs present in pUL56, suggesting that late domains are required for pUL43- and pUL56-dependent sorting of MHC class I for lysosomal degradation. IMPORTANCE We describe here that the poorly characterized herpesviral protein pUL43 is involved in downregulation of cell surface MHC-I. pUL43 is an early protein and degraded in lysosomes. pUL43 resides in the Golgi vesicles and needs an intact N terminus to induce MHC-I downregulation in infected cells. Importantly, pUL43 and pUL56 cooperate to reduce MHC-I expression on the surface of transfected cells. Our results suggest a model for

  8. Genomic Alterations in CIITA Are Frequent in Primary Mediastinal Large B Cell Lymphoma and Are Associated with Diminished MHC Class II Expression.

    PubMed

    Mottok, Anja; Woolcock, Bruce; Chan, Fong Chun; Tong, King Mong; Chong, Lauren; Farinha, Pedro; Telenius, Adèle; Chavez, Elizabeth; Ramchandani, Suvan; Drake, Marie; Boyle, Merrill; Ben-Neriah, Susana; Scott, David W; Rimsza, Lisa M; Siebert, Reiner; Gascoyne, Randy D; Steidl, Christian

    2015-11-17

    Primary mediastinal large B cell lymphoma (PMBCL) is an aggressive non-Hodgkin's lymphoma, predominantly affecting young patients. We analyzed 45 primary PMBCL tumor biopsies and 3 PMBCL-derived cell lines for the presence of genetic alterations involving the major histocompatibility complex (MHC) class II transactivator CIITA and found frequent aberrations consisting of structural genomic rearrangements, missense, nonsense, and frame-shift mutations (53% of primary tumor biopsies and all cell lines). We also detected intron 1 mutations in 47% of the cases, and detailed sequence analysis strongly suggests AID-mediated aberrant somatic hypermutation as the mutational mechanism. Furthermore, we demonstrate that genomic lesions in CIITA result in decreased protein expression and reduction of MHC class II surface expression, creating an immune privilege phenotype in PMBCL. In summary, we establish CIITA alterations as a common mechanism of immune escape through reduction of MHC class II expression in PMBCL, with potential implications for future treatments targeting microenvironment-related biology.

  9. Engineering of chimeric class II polyhydroxyalkanoate synthases.

    PubMed

    Niamsiri, Nuttawee; Delamarre, Soazig C; Kim, Young-Rok; Batt, Carl A

    2004-11-01

    PHA synthase is a key enzyme involved in the biosynthesis of polyhydroxyalkanoates (PHAs). Using a combinatorial genetic strategy to create unique chimeric class II PHA synthases, we have obtained a number of novel chimeras which display improved catalytic properties. To engineer the chimeric PHA synthases, we constructed a synthetic phaC gene from Pseudomonas oleovorans (phaC1Po) that was devoid of an internal 540-bp fragment. Randomly amplified PCR products (created with primers based on conserved phaC sequences flanking the deleted internal fragment) were generated using genomic DNA isolated from soil and were substituted for the 540-bp internal region. The chimeric genes were expressed in a PHA-negative strain of Ralstonia eutropha, PHB(-)4 (DSM 541). Out of 1,478 recombinant clones screened for PHA production, we obtained five different chimeric phaC1Po genes that produced more PHA than the native phaC1Po. Chimeras S1-71, S4-8, S5-58, S3-69, and S3-44 exhibited 1.3-, 1.4-, 2.0-, 2.1-, and 3.0-fold-increased levels of in vivo activity, respectively. All of the mutants mediated the synthesis of PHAs with a slightly increased molar fraction of 3-hydroxyoctanoate; however, the weight-average molecular weights (Mw) of the PHAs in all cases remained almost the same. Based upon DNA sequence analyses, the various phaC fragments appear to have originated from Pseudomonas fluorescens and Pseudomonas aureofaciens. The amino acid sequence analyses showed that the chimeric proteins had 17 to 20 amino acid differences from the wild-type phaC1Po, and these differences were clustered in the same positions in the five chimeric clones. A threading model of PhaC1Po, developed based on homology of the enzyme to the Burkholderia glumae lipase, suggested that the amino acid substitutions found in the active chimeras were located mostly on the protein model surface. Thus, our combinatorial genetic engineering strategy proved to be broadly useful for improving the catalytic

  10. Management of Class II malocclusion with ectopic maxillary canines

    PubMed Central

    Mascarenhas, Rohan; Parveen, Shahista; Ansari, Tariq Aziz

    2015-01-01

    Correction of Class II relationship, deep bite and ectopically erupting canines is an orthodontic challenge for the clinician. A 13-year-old male patient presented with Class II malocclusion, ectopically erupting canines, and cross bite with maxillary left lateral incisor. He was treated with a combination of Headgear, Forsus™ fatigue resistant device [FFRD] with fixed mechanotherapy for the management of space deficiency and correction of Class II malocclusions. Headgear was used to distalize upper first molars and also to prevent further downward and forward growth of the maxilla. Then Forsus™ FFRD was used for the advancement of the mandible. The molar and canine relationship were corrected from a Class II to a Class I. The objectives were to establish good occlusion and enable eruption of unerupted canines. All these objectives were achieved and remained stable. PMID:26097371

  11. HLA Class I and Class II Conserved Extended Haplotypes and Their Fragments or Blocks in Mexicans: Implications for the Study of Genetic Diversity in Admixed Populations

    PubMed Central

    Ohashi, Marina; Lebedeva, Tatiana; Acuña-Alonzo, Víctor; Yunis, María; Granados-Montiel, Julio; Cruz-Lagunas, Alfredo; Vargas-Alarcón, Gilberto; Rodríguez-Reyna, Tatiana S.; Fernandez-Viña, Marcelo; Granados, Julio; Yunis, Edmond J.

    2013-01-01

    Major histocompatibility complex (MHC) genes are highly polymorphic and informative in disease association, transplantation, and population genetics studies with particular importance in the understanding of human population diversity and evolution. The aim of this study was to describe the HLA diversity in Mexican admixed individuals. We studied the polymorphism of MHC class I (HLA-A, -B, -C), and class II (HLA-DRB1, -DQB1) genes using high-resolution sequence based typing (SBT) method and we structured the blocks and conserved extended haplotypes (CEHs) in 234 non-related admixed Mexican individuals (468 haplotypes) by a maximum likelihood method. We found that HLA blocks and CEHs are primarily from Amerindian and Caucasian origin, with smaller participation of African and recent Asian ancestry, demonstrating a great diversity of HLA blocks and CEHs in Mexicans from the central area of Mexico. We also analyzed the degree of admixture in this group using short tandem repeats (STRs) and HLA-B that correlated with the frequency of most probable ancestral HLA-C/−B and -DRB1/−DQB1 blocks and CEHs. Our results contribute to the analysis of the diversity and ancestral contribution of HLA class I and HLA class II alleles and haplotypes of Mexican admixed individuals from Mexico City. This work will help as a reference to improve future studies in Mexicans regarding allotransplantation, immune responses and disease associations. PMID:24086347

  12. Murine neuroblastoma vaccines produced by retroviral transfer of MHC class II genes.

    PubMed

    Hock, R A; Reynolds, B D; Tucker-McClung, C L; Heuer, J G

    1996-01-01

    Malignant tumors express tumor-related antigens, but effective antitumor immunity does not occur in the primary host. One hypothesis is that there is insufficient stimulation of T-cell responses due to ineffective antigen presentation. An approach to overcome these deficiencies is to modify tumor cells to express major histocompatibility complex (MHC) class II genes and thus facilitate the presentation of antigens directly by tumor cells. Our experiments with a murine neuroblastoma cell line (neuro-2a) transduced with DR (xenogeneic), 1-Ab (allogeneic), or 1-Ak (syngeneic) MHC class II genes support this notion. The relative potencies of the modified neuro-2a to induce immunity to unmodified neuro-2a were neuro-2a/DR > neuro-2a/1-Ab > neuro-2a/1-Ak. Modified neuro-2a also could stimulate naive splenocyte proliferation in vitro. The relative magnitude of the proliferative responses seen after stimulation with modified tumor cells was neuro-2a/DR > neuro-2a/1-Ab > neuro-2a/1-Ak > unmodified neuro-2a. Hence, the tumor cell-induced splenocyte proliferative responses observed in vitro correlate with the effectiveness of the tumor cell vaccines to induce antitumor immunity in vivo. These data show that the expression of exogenous MHC class II on tumor cells is a potent stimulus for specific antitumor immunity. Because of the correlation of the in vivo and in vitro immune responses to modified tumor cells, the tumor-induced lymphocyte proliferation assay may be useful in evaluating tumor cell vaccines produced by additional genetic modifications of tumor cells.

  13. Characterization of MHC class I and II genes in a subantarctic seabird, the blue petrel, Halobaena caerulea (Procellariiformes).

    PubMed

    Strandh, Maria; Lannefors, Mimi; Bonadonna, Francesco; Westerdahl, Helena

    2011-10-01

    The great polymorphism observed in the major histocompatibility complex (MHC) genes is thought to be maintained by pathogen-mediated selection possibly combined with MHC-disassortative mating, guided by MHC-determined olfactory cues. Here, we partly characterize the MHC class I and II B of the blue petrel, Halobaena caerulea (Procellariiformes), a bird with significant olfactory abilities that lives under presumably low pathogen burdens in Subantarctica. Blue petrels are long-lived, monogamous birds which suggest the necessity of an accurate mate choice process. The species is ancestral to songbirds (Passeriformes; many MHC loci), although not to gamefowls (Galliformes; few MHC loci). Considering the phylogenetic relationships and the low subantarctic pathogen burden, we expected few rather than many MHC loci in the blue petrel. However, when we analysed partial MHC class I and class II B cDNA and gDNA sequences we found evidence for as many as at least eight MHC class I loci and at least two class II B loci. These class I and II B sequences showed classical MHC characteristics, e.g. high nucleotide diversity, especially in putative peptide-binding regions where signatures of positive selection was detected. Trans-species polymorphism was found between MHC class II B sequences of the blue petrel and those of thin-billed prion, Pachyptila belcheri, two species that diverged ∼25 MYA. The observed MHC allele richness in the blue petrel may well serve as a basis for mate choice, especially since olfactory discrimination of MHC types may be possible in this species. PMID:21607694

  14. Archform Comparisons between Skeletal Class II and III Malocclusions

    PubMed Central

    Jiang, JiuHui; Xu, TianMin; Li, CuiYing

    2014-01-01

    The purpose of this cross-sectional research was to explore the relationship of the mandibular dental and basal bone archforms between severe Skeletal Class II (SC2) and Skeletal Class III (SC3) malocclusions. We also compared intercanine and intermolar widths in these two malocclusion types. Thirty-three virtual pretreatment mandibular models (Skeletal Class III group) and Thirty-five Skeletal Class II group pretreatment models were created with a laser scanning system. FA (the midpoint of the facial axis of the clinical crown)and WALA points (the most prominent point on the soft-tissue ridge)were employed to produce dental and basal bone archforms, respectively. Gained scatter diagrams of the samples were processed by nonlinear regression analysis via SPSS 17.0. The mandibular dental and basal bone intercanine and intermolar widths were significantly greater in the Skeletal Class III group compared to the Skeletal Class II group. In both groups, a moderate correlation existed between dental and basal bone arch widths in the canine region, and a high correlation existed between dental and basal bone arch widths in the molar region. The coefficient of correlation of the Skeletal Class III group was greater than the Skeletal Class II group. Fourth degree, even order power functions were used as best-fit functions to fit the scatter plots. The radius of curvature was larger in Skeletal Class III malocclusions compared to Skeletal Class II malocclusions (rWALA3>rWALA2>rFA3>rFA2). In conclusion, mandibular dental and basal intercanine and intermolar widths were significantly different between the two groups. Compared with Skeletal Class II subjects, the mandibular archform was more flat for Skeletal Class III subjects. PMID:24971597

  15. Disparate MHC class II haplotypes in myelin oligodendrocyte glycoprotein- and myelin basic protein-induced experimental autoimmune encephalomyelitis.

    PubMed

    Muhallab, Saad; Dahlman, Ingrid; Wallström, Erik

    2005-04-01

    The major histocompatibility complex (MHC) regulates multiple sclerosis (MS) and its model experimental autoimmune encephalomyelitis (EAE). We created four new intra-MHC recombinant rat strains, between the MHC haplotypes RT1(n) (BN) and RT1(l) (LEW) on the LEW background, to define disease regulation and localization within the MHC. Immunization with recombinant myelin oligodendrocyte glycoprotein (a.a.1-125; MOG)/IFA induced EAE in strains expressing the MHC class II allele RT1.B(n), whereas strains expressing the RT1.B(l) were resistant. In myelin basic protein peptide (MBP(GP)63-88)/CFA-induced EAE, RT1.B(l) expressing strains were susceptible whereas strains expressing the RT1.B(n) were resistant. High levels of antigen-specific IFN-gamma secreting lymphoid cells and antigen-specific serum IgG antibodies were only recorded in rats with an MHC class II allele that permitted MOG- or MBP-EAE, respectively. Genetically, we localized the MHC regulation of the investigated EAE models to the central part of the MHC, containing the MHC class II (RT1.B/D) and the centromeric parts of the MHC class III. No influences were evident from the classical MHC class I (RT1.A), the telomeric parts of the MHC class III or the non-classical MHC class I (RT1.C/E/M) in contrast to previous reports. The MHC class II haplotype-specific regulation of EAE induced with two different CNS antigens demonstrates a strikingly specific MHC-association even within the same target organ. PMID:15748954

  16. Evidence of a second polymorphic ELA class I (ELA-B) locus and gene order for three loci of the equine major histocompatibility complex.

    PubMed

    Bernoco, D; Byrns, G; Bailey, E; Lew, A M

    1987-01-01

    Two antisera, B-442 and R-2046, were produced by immunizing offspring with purified peripheral blood lymphocytes from a parent matched for the ELA-A specificity carried on the unshared haplotype. Absorption analysis demonstrated that these antisera contained at least two families of cytotoxic antibodies, one directed against antigens present on T and B cells, and a second directed preferentially against antigens present on surface Ig positive cells. Immunoprecipitation studies using these antisera demonstrated that both antisera contain antibodies specific for glycoproteins with molecular weights characteristic of class I and class II MHC antigens. In lymphocyte typing tests of unfractionated lymphocytes, only the class I activity was readily detectable since the class II activity killed less than 25% of the cells. Family studies demonstrated that these antisera recognize products of genes linked to the ELA system. Based on two recombinants in an extended family it became apparent that the specificities detected by B-442 and R-2046 are not products of the ELA-A locus, but rather they are products of at least one other locus, defined in this paper as ELA-B. In this family a third recombinant was found between the A blood group system and the ELA-A locus. Based on these three recombinants, the most probable linear relationship of the following genes is: A blood group system/ELA-A/ELA-B.

  17. Recognition of the Major Histocompatibility Complex (MHC) Class Ib Molecule H2-Q10 by the Natural Killer Cell Receptor Ly49C.

    PubMed

    Sullivan, Lucy C; Berry, Richard; Sosnin, Natasha; Widjaja, Jacqueline M L; Deuss, Felix A; Balaji, Gautham R; LaGruta, Nicole L; Mirams, Michiko; Trapani, Joseph A; Rossjohn, Jamie; Brooks, Andrew G; Andrews, Daniel M

    2016-09-01

    Murine natural killer (NK) cells are regulated by the interaction of Ly49 receptors with major histocompatibility complex class I molecules (MHC-I). Although the ligands for inhibitory Ly49 were considered to be restricted to classical MHC (MHC-Ia), we have shown that the non-classical MHC molecule (MHC-Ib) H2-M3 was a ligand for the inhibitory Ly49A. Here we establish that another MHC-Ib, H2-Q10, is a bona fide ligand for the inhibitory Ly49C receptor. H2-Q10 bound to Ly49C with a marginally lower affinity (∼5 μm) than that observed between Ly49C and MHC-Ia (H-2K(b)/H-2D(d), both ∼1 μm), and this recognition could be prevented by cis interactions with H-2K in situ To understand the molecular details underpinning Ly49·MHC-Ib recognition, we determined the crystal structures of H2-Q10 and Ly49C bound H2-Q10. Unliganded H2-Q10 adopted a classical MHC-I fold and possessed a peptide-binding groove that exhibited features similar to those found in MHC-Ia, explaining the diverse peptide binding repertoire of H2-Q10. Ly49C bound to H2-Q10 underneath the peptide binding platform to a region that encompassed residues from the α1, α2, and α3 domains, as well as the associated β2-microglobulin subunit. This docking mode was conserved with that previously observed for Ly49C·H-2K(b) Indeed, structure-guided mutation of Ly49C indicated that Ly49C·H2-Q10 and Ly49C·H-2K(b) possess similar energetic footprints focused around residues located within the Ly49C β4-stand and L5 loop, which contact the underside of the peptide-binding platform floor. Our data provide a structural basis for Ly49·MHC-Ib recognition and demonstrate that MHC-Ib represent an extended family of ligands for Ly49 molecules. PMID:27385590

  18. Role of major histocompatibility complex class I-related molecules A*A5·1 allele in ulcerative colitis in Chinese patients

    PubMed Central

    Lü, Min; Xia, Bing; Ge, Liuqing; Li, Yi; Zhao, Jie; Chen, Fan; Zhou, Feng; Zhang, Xiaolian; Tan, Jinquan

    2009-01-01

    The major histocompatibility complex (MHC) class I-related molecules A (MICA) is a stress-inducible cell surface antigen that is recognized by intestinal epithelial Vδ1 γδ T cells, natural killer (NK) cells and CD8+ T cells with NKG2D receptor participating in the immunological reaction in the intestinal mucosa. The present study aimed to investigate the functions of the MICA*A5.1 allele in the development of ulcerative colitis (UC) in the Chinese population. The microsatellite polymorphisms of MICA were genotyped in 124 unrelated Chinese patients with UC and 172 ethnically matched healthy controls using a semiautomatic fluorescently labelled polymerase chain reaction. MICA*A5.1-expressing Raji cells were generated by gene transfection. Cytotoxicity of NK cells to Raji cells expressing different MICA molecules was detected using the lactate dehydrogenase method. Soluble MICA in the culture supernatant was detected by enzyme-linked immunosorbent assay. The frequency of MICA*A5.1 was significantly higher in UC patients compared with the healthy controls (29·0% versus 17·4%, P= 0·001, corrected P= 0·005, OR = 1·936, 95% CI 1·310–2·863) and the frequency of a MICA*A5.1/A5.1 homozygous genotype was increased in UC patients (18·5% versus 7% in healthy controls, P= 0·0032, corrected P= 0·048, OR = 3·036, 95% CI 1·447–6·372). Raji cells with MICA*A5.1 expression produced more soluble MICA (t = 5·75, P < 0·01) than Raji cells with full-length MICA expression in culture supernatant. Raji cells with MICA*A5.1 expression were more resistant to killing by NK cells than Raji cells with full-length MICA expression. The MICA*A5.1 allele and MICA*A5.1/A5.1 genotype are significantly associated with Chinese UC patients in central China. MICA*A5.1 may play a role in the development of UC by producing more soluble MICA and resistance to NK cells. PMID:19016911

  19. Expression of bovine non-classical major histocompatibility complex class I proteins in mouse P815 and human K562 cells.

    PubMed

    Parasar, Parveen; Wilhelm, Amanda; Rutigliano, Heloisa M; Thomas, Aaron J; Teng, Lihong; Shi, Bi; Davis, William C; Suarez, Carlos E; New, Daniel D; White, Kenneth L; Davies, Christopher J

    2016-08-01

    Major histocompatibility complex class I (MHC-I) proteins can be expressed as cell surface or secreted proteins. To investigate whether bovine non-classical MHC-I proteins are expressed as cell surface or secreted proteins, and to assess the reactivity pattern of monoclonal antibodies with non-classical MHC-I isoforms, we expressed the MHC proteins in murine P815 and human K562 (MHC-I deficient) cells. Following antibiotic selection, stably transfected cell lines were stained with H1A or W6/32 antibodies to detect expression of the MHC-I proteins by flow cytometry. Two non-classical proteins (BoLA-NC1*00501 and BoLA-NC3*00101) were expressed on the cell surface in both cell lines. Surprisingly, the BoLA-NC4*00201 protein was expressed on the cell membrane of human K562 but not mouse P815 cells. Two non-classical proteins (BoLA-NC1*00401, which lacks a transmembrane domain, and BoLA-NC2*00102) did not exhibit cell surface expression. Nevertheless, Western blot analyses demonstrated expression of the MHC-I heavy chain in all transfected cell lines. Ammonium-sulfate precipitation of proteins from culture supernatants showed that BoLA-NC1*00401 was secreted and that all surface expressed proteins where shed from the cell membrane by the transfected cells. Interestingly, the surface expressed MHC-I proteins were present in culture supernatants at a much higher concentration than BoLA-NC1*00401. This comprehensive study shows that bovine non-classical MHC-I proteins BoLA-NC1*00501, BoLA-NC3*00101, and BoLA-NC4*00201 are expressed as surface isoforms with the latter reaching the cell membrane only in K562 cells. Furthermore, it demonstrated that BoLA-NC1*00401 is a secreted isoform and that significant quantities of membrane associated MHC-I proteins can be shed from the cell membrane. PMID:27473990

  20. Class II barodontalgia: review and report of a case.

    PubMed

    Woodmansey, Karl

    2008-01-01

    Barodontalgia is a rarely reported condition involving changes in ambient pressure resulting in tooth pain. According to Ferjentsik and Aker, Class II barodontalgia is observed in teeth that have pre-existing pulpal disease and an ultimate diagnosis of irreversible pulpitis.1 This article describes a case of Class II barodontalgia that was experienced on a commercial airline flight and reviews current knowledge regarding this phenomenon, including proposed etiologic mechanisms.

  1. MHC class II diversity of koala (Phascolarctos cinereus) populations across their range.

    PubMed

    Lau, Q; Jaratlerdsiri, W; Griffith, J E; Gongora, J; Higgins, D P

    2014-10-01

    Major histocompatibility complex class II (MHCII) genes code for proteins that bind and present antigenic peptides and trigger the adaptive immune response. We present a broad geographical study of MHCII DA β1 (DAB) and DB β1 (DBB) variants of the koala (Phascolarctos cinereus; n=191) from 12 populations across eastern Australia, with a total of 13 DAB and 7 DBB variants found. We identified greater MHCII variation and, possibly, additional gene copies in koala populations in the north (Queensland and New South Wales) relative to the south (Victoria), confirmed by STRUCTURE analyses and genetic differentiation using analysis of molecular variance. The higher MHCII diversity in the north relative to south could potentially be attributed to (i) significant founder effect in Victorian populations linked to historical translocation of bottlenecked koala populations and (ii) increased pathogen-driven balancing selection and/or local genetic drift in the north. Low MHCII genetic diversity in koalas from the south could reduce their potential response to disease, although the three DAB variants found in the south had substantial sequence divergence between variants. This study assessing MHCII diversity in the koala with historical translocations in some populations contributes to understanding the effects of population translocations on functional genetic diversity.

  2. High levels of MHC class II allelic diversity in lake trout from Lake Superior

    USGS Publications Warehouse

    Dorschner, M.O.; Duris, T.; Bronte, C.R.; Burnham-Curtis, M. K.; Phillips, R.B.

    2000-01-01

    Sequence variation in a 216 bp portion of the major histocompatibility complex (MHC) II B1 domain was examined in 74 individual lake trout (Salvelinus namaycush) from different locations in Lake Superior. Forty-three alleles were obtained which encoded 71-72 amino acids of the mature protein. These sequences were compared with previous data obtained from five Pacific salmon species and Atlantic salmon using the same primers. Although all of the lake trout alleles clustered together in the neighbor-joining analysis of amino acid sequences, one amino acid allelic lineage was shared with Atlantic salmon (Salmo salar), a species in another genus which probably diverged from Salvelinus more than 10-20 million years ago. As shown previously in other salmonids, the level of nonsynonymous nucleotide substitution (d(N)) exceeded the level of synonymous substitution (d(S)). The level of nucleotide diversity at the MHC class II B1 locus was considerably higher in lake trout than in the Pacific salmon (genus Oncorhynchus). These results are consistent with the hypothesis that lake trout colonized Lake Superior from more than one refuge following the Wisconsin glaciation. Recent population bottlenecks may have reduced nucleotide diversity in Pacific salmon populations.

  3. MHC class II diversity of koala (Phascolarctos cinereus) populations across their range

    PubMed Central

    Lau, Q; Jaratlerdsiri, W; Griffith, J E; Gongora, J; Higgins, D P

    2014-01-01

    Major histocompatibility complex class II (MHCII) genes code for proteins that bind and present antigenic peptides and trigger the adaptive immune response. We present a broad geographical study of MHCII DA β1 (DAB) and DB β1 (DBB) variants of the koala (Phascolarctos cinereus; n=191) from 12 populations across eastern Australia, with a total of 13 DAB and 7 DBB variants found. We identified greater MHCII variation and, possibly, additional gene copies in koala populations in the north (Queensland and New South Wales) relative to the south (Victoria), confirmed by STRUCTURE analyses and genetic differentiation using analysis of molecular variance. The higher MHCII diversity in the north relative to south could potentially be attributed to (i) significant founder effect in Victorian populations linked to historical translocation of bottlenecked koala populations and (ii) increased pathogen-driven balancing selection and/or local genetic drift in the north. Low MHCII genetic diversity in koalas from the south could reduce their potential response to disease, although the three DAB variants found in the south had substantial sequence divergence between variants. This study assessing MHCII diversity in the koala with historical translocations in some populations contributes to understanding the effects of population translocations on functional genetic diversity. PMID:24690756

  4. Diagnostic features of Angle's Class II div 2 malocclusion

    PubMed Central

    Dodda, Kiran Kumar; Prasad, Singamsetty E. R. V.; Kanuru, Ravi Krishna; Nalluri, Siddhartha; Mittapalli, Radhika; Raghavendra

    2015-01-01

    Statement of Problem: A thorough knowledge of the salient features of malocclusion makes the practitioner to come to a proper diagnosis and to formulate proper mechanotherapy. It also helps to predict the prognosis, prior to the onset of treatment process. Among the various malocclusions, Class II div 2 occurs the least often. The literature review does not clearly describe the classical skeletal and dental features of Angle's Class II div 2 malocclusion. Purpose of Study: The aim of this study is to describe the unique features of Angle's Class II division 2 malocclusion. Materials and Methods: A total of 612 pre-treatment records (study models and cephalograms), with age ranging from 14 to 25 years, were obtained from the hospital records of Drs Sudha and Nageswar Rao Siddhartha Institute of Dental Sciences. Among these samples, 317 were Class II div 1 and 295 were Class II div 2. The lateral cephalograms were analyzed by using Kodak software and the arch width analysis was calculated by using digital vernier calipers. Results: Student's t test was used for the study. On the cephalograms, the vertical skeletal measurements and few of the dental variables showed a significant difference. On the plaster models, the maxillary transverse measurements revealed a notable discrimination between the groups. Conclusion: Angle's Class II div 2 malocclusion has a marked horizontal growth pattern with decreased lower facial thirds, palatally inclined upper anteriors, and remarkably increased transverse maxillary arch dimensions. PMID:26759807

  5. Coordinated changes of histone modifications and HDAC mobilization regulate the induction of MHC class II genes by Trichostatin A

    PubMed Central

    2006-01-01

    The deacetylase inhibitor Trichostatin A (TSA) induces the transcription of the Major Histocompatibility Class II (MHC II) DRA gene in a way independent of the master coactivator CIITA. To analyze the molecular mechanisms by which this epigenetic regulator stimulates MHC II expression, we used chromatin immunoprecipitation (ChIP) assays to monitor the alterations in histone modifications that correlate with DRA transcription after TSA treatment. We found that a dramatic increase in promoter linked histone acetylation is followed by an increase in Histone H3 lysine 4 methylation and a decrease of lysine 9 methylation. Fluorescence recovery after photobleaching (FRAP) experiments showed that TSA increases the mobility of HDAC while decreasing the mobility of the class II enhanceosome factor RFX5. These data, in combination with ChIP experiments, indicate that the TSA-mediated induction of DRA transcription involves HDAC relocation and enhanceosome stabilization. In order to gain a genome-wide view of the genes responding to inhibition of deacetylases, we compared the transcriptome of B cells before and after TSA treatment using Affymetrix microarrays. This analysis showed that in addition to the DRA gene, the entire MHC II family and the adjacent histone cluster that are located in chromosome 6p21-22 locus are strongly induced by TSA. A complex pattern of gene reprogramming by TSA involves immune recognition, antiviral, apoptotic and inflammatory pathways and extends the rationale for using Histone Deacetylase Inhibitors (HDACi) to modulate the immune response. PMID:16452299

  6. The histone acetyltransferase domains of CREB-binding protein (CBP) and p300/CBP-associated factor are not necessary for cooperativity with the class II transactivator.

    PubMed

    Harton, J A; Zika, E; Ting, J P

    2001-10-19

    The class II transactivator (CIITA) is a transcriptional co-activator regulating the constitutive and interferon-gamma-inducible expression of class II major histocompatibility complex (MHC) and related genes. Promoter remodeling occurs following CIITA induction, suggesting the involvement of chromatin remodeling factors. Transcription of numerous genes requires the histone acetyltransferase (HAT) activities of CREB-binding protein (CBP), p300, and/or p300/CBP-associated factor (pCAF). These co-activators cooperate with CIITA and are hypothesized to promote class II major histocompatibility complex transcription through their HAT activity. To directly test this, we used HAT-defective CBP and pCAF. We demonstrate that cooperation between CIITA and CBP is independent of CBP HAT activity. Further, although pCAF enhances CIITA-mediated transcription, pCAF HAT domain dependence appears contingent upon the concentration of available CIITA. When HAT-defective CBP and pCAF are both present, cooperativity with CIITA is maintained. Consistent with a recent report, we show that nuclear localization of CIITA is enhanced by lysine 144, an in vitro target of pCAF-mediated HAT. Yet we find that neither mutation of lysine 144 nor deletion of residues 132-209 affects transcriptional cooperation with CBP or pCAF. Thus, acetylation of this residue may not be the primary mechanism for pCAF/CBP cooperation with CIITA. In conclusion, the HAT activities of the co-activators are not necessary for cooperation with CIITA.

  7. 18 CFR 415.21 - Class II projects.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Class II projects. 415.21 Section 415.21 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... part, include all projects other than Class I projects, in non-tidal areas of the basin, which...

  8. 18 CFR 415.21 - Class II projects.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Class II projects. 415.21 Section 415.21 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... part, include all projects other than Class I projects, in non-tidal areas of the basin, which...

  9. 18 CFR 415.21 - Class II projects.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Class II projects. 415.21 Section 415.21 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... part, include all projects other than Class I projects, in non-tidal areas of the basin, which...

  10. 18 CFR 415.21 - Class II projects.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Class II projects. 415.21 Section 415.21 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION... part, include all projects other than Class I projects, in non-tidal areas of the basin, which...

  11. Development of a simultaneous high resolution typing method for three SLA class II genes, SLA-DQA, SLA-DQB1, and SLA-DRB1 and the analysis of SLA class II haplotypes.

    PubMed

    Le, MinhThong; Choi, Hojun; Choi, Min-Kyeung; Cho, Hyesun; Kim, Jin-Hoi; Seo, Han Geuk; Cha, Se-Yeon; Seo, Kunho; Dadi, Hailu; Park, Chankyu

    2015-06-15

    The characterization of the genetic variations of major histocompatibility complex (MHC) is essential to understand the relationship between the genetic diversity of MHC molecules and disease resistance and susceptibility in adaptive immunity. We previously reported the development of high-resolution individual locus typing methods for three of the most polymorphic swine leukocyte antigens (SLA) class II loci, namely, SLA-DQA, SLA-DQB1, and SLA-DRB1. In this study, we extensively modified our previous protocols and developed a method for the simultaneous amplification of the three SLA class II genes and subsequent analysis of individual loci using direct sequencing. The unbiased and simultaneous amplification of alleles from the all three hyper-polymorphic and pseudogene containing genes such as MHC genes is extremely challenging. However, using this method, we demonstrated the successful typing of SLA-DQA, SLA-DQB1, and SLA-DRB1 for 31 selected individuals comprising 26 different SLA class II haplotypes which were identified from 700 animals using the single locus typing methods. The results were identical to the known genotypes from the individual locus typing. The new method has significant benefits over the individual locus typing, including lower typing cost, use of less biomaterial, less effort and fewer errors in handling large samples for multiple loci. We also extensively characterized the haplotypes of SLA class II genes and reported three new haplotypes. Our results should serve as a basis to investigate the possible association between polymorphisms of MHC class II and differences in immune responses to exogenous antigens.

  12. Bacterial superantigens promote acute nasopharyngeal infection by Streptococcus pyogenes in a human MHC Class II-dependent manner.

    PubMed

    Kasper, Katherine J; Zeppa, Joseph J; Wakabayashi, Adrienne T; Xu, Stacey X; Mazzuca, Delfina M; Welch, Ian; Baroja, Miren L; Kotb, Malak; Cairns, Ewa; Cleary, P Patrick; Haeryfar, S M Mansour; McCormick, John K

    2014-05-01

    Establishing the genetic determinants of niche adaptation by microbial pathogens to specific hosts is important for the management and control of infectious disease. Streptococcus pyogenes is a globally prominent human-specific bacterial pathogen that secretes superantigens (SAgs) as 'trademark' virulence factors. SAgs function to force the activation of T lymphocytes through direct binding to lateral surfaces of T cell receptors and class II major histocompatibility complex (MHC-II) molecules. S. pyogenes invariably encodes multiple SAgs, often within putative mobile genetic elements, and although SAgs are documented virulence factors for diseases such as scarlet fever and the streptococcal toxic shock syndrome (STSS), how these exotoxins contribute to the fitness and evolution of S. pyogenes is unknown. Here we show that acute infection in the nasopharynx is dependent upon both bacterial SAgs and host MHC-II molecules. S. pyogenes was rapidly cleared from the nasal cavity of wild-type C57BL/6 (B6) mice, whereas infection was enhanced up to ∼10,000-fold in B6 mice that express human MHC-II. This phenotype required the SpeA superantigen, and vaccination with an MHC -II binding mutant toxoid of SpeA dramatically inhibited infection. Our findings indicate that streptococcal SAgs are critical for the establishment of nasopharyngeal infection, thus providing an explanation as to why S. pyogenes produces these potent toxins. This work also highlights that SAg redundancy exists to avoid host anti-SAg humoral immune responses and to potentially overcome host MHC-II polymorphisms.

  13. 40 CFR 144.19 - Transitioning from Class II to Class VI.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Transitioning from Class II to Class VI. 144.19 Section 144.19 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) UNDERGROUND INJECTION CONTROL PROGRAM General Program Requirements §...

  14. 40 CFR 144.19 - Transitioning from Class II to Class VI.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Transitioning from Class II to Class VI. 144.19 Section 144.19 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) UNDERGROUND INJECTION CONTROL PROGRAM General Program Requirements §...

  15. 40 CFR 144.19 - Transitioning from Class II to Class VI.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Transitioning from Class II to Class VI. 144.19 Section 144.19 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED) UNDERGROUND INJECTION CONTROL PROGRAM General Program Requirements §...

  16. The peculiar distribution of class I and class II aldolases in diatoms and in red algae.

    PubMed

    Kroth, Peter G; Schroers, Yvonne; Kilian, Oliver

    2005-12-01

    Diatom plastids probably evolved by secondary endocytobiosis from a red alga that was up by a eukaryotic host cell. Apparently, this process increased the complexity of the intracellular distribution of metabolic enzymes. We identified genes encoding fructose-bisphosphate aldolases (FBA) in two centric (Odontella sinensis, Thalassiosira pseudonana) and one pennate (Phaeodactylum tricornutum) diatoms and found that four different aldolases are present in both groups: two plastid targeted class II enzymes (FBAC1 and FBAC2), one cytosolic class II (FBA3) and one cytosolic class I (FBA4) enzyme. The pennate Phaeodactylum possesses an additional plastidic class I enzyme (FBAC5). We verified the classification of the different aldolases in the diatoms by enzymatic characterization of isolated plastids and whole cell extracts. Interestingly, our results imply that in plastids of centric and pennate diatoms mainly either class I or class II aldolases are active. We also identified genes for both class I and class II aldolases in red algal EST databases, thus presenting a fascinating example of the reutilization and recompartmentalization of different aldolase isoenzymes during secondary endocytobiosis but as well demonstrating the limited use of metabolic enzymes as markers for the interpretation of phylogenetic histories in algae.

  17. Multivesicular bodies in intestinal epithelial cells: responsible for MHC class II-restricted antigen processing and origin of exosomes

    PubMed Central

    Büning, Jürgen; von Smolinski, Dorthe; Tafazzoli, Kianush; Zimmer, Klaus-Peter; Strobel, Stephan; Apostolaki, Maria; Kollias, George; Heath, Joan K; Ludwig, Diether; Gebert, Andreas

    2008-01-01

    In normal conditions intestinal epithelial cells (IECs) constitutively stimulate regulatory CD4+ T cells. However, in Crohn's disease (CD), this major histocompatibility complex (MHC) class II-restricted antigen presentation results in stimulation of proinflammatory CD4+ T cells. We hypothesized that these alternative functions might be mediated by differential sorting and processing of antigens into distinct MHC II-enriched compartments (MIICs). Accordingly, we analysed the endocytic pathways of lumenally applied ovalbumin (OVA) in IECs of the jejunum and ileum of wild-type (WT) and TNFΔARE/WT mice that develop a CD-resembling ileitis. Using quantitative reverse transcription polymerase chain reaction, we found that messenger RNA levels of interferon-γ, tumour necrosis factor-α, interleukin-17 and interleukin-10 were significantly up-regulated in the inflamed ileum of TNFΔARE/WT mice, confirming CD-like inflammation. Fluorescence and immunoelectron microscopy revealed the presence of MHC II and invariant chain throughout the late endocytic compartments, with most molecules concentrated in the multivesicular bodies (MVB). OVA was targeted into MVB and, in contrast to other MIICs, accumulated in these structures within 120 min of exposure. The IEC-specific A33 antigen localized to internal vesicles of MVB and A33/class II-bearing exosomes were identified in intercellular spaces. Remarkably, the expression pattern of MHC II/invariant chain molecules and the trafficking of OVA were independent of mucosal inflammation and the specific region in the small intestine. MVB seem to be principally responsible for class II-associated antigen processing in IECs and to constitute the origin of MHC II-loaded exosomes. The distinctive functions of IECs in antigen presentation to CD4+ T cells might arise as a result of differential processing within the MVB identified here. PMID:18710406

  18. PowerScope a Class II corrector - A case report.

    PubMed

    Paulose, Joby; Antony, Palathottungal Joseph; Sureshkumar, Brijesh; George, Susha Mariam; Mathew, Manu Mundackal; Sebastian, Joseph

    2016-01-01

    Managing mild to moderate Class II malocclusion is a one of the common and major challenges to orthodontists. Class II discrepancies with mandibular deficiency during active growth are usually treated by myofunctional appliances. Fixed functional appliances evolved due to the noncompliance with conventional myofunctional appliances. This case report illustrates the efficiency of PowerScope in correction of skeletal Class II with mandibular deficiency in a patient aged 13 years who has reported to the department with a chief complaint of forwardly placed upper front teeth. This case with functional jaw retrusion was treated initially with MBT 0.022" prescription followed by PowerScope. Pre-, mid- and post-treatment cephalograms were obtained, and cephalometric analysis was performed. Stable and successful results were obtained with a substantial improvement in facial profile, skeletal jaw relationship, and overall esthetic appearance of the patient. A significant forward displacement of the mandible was the principal element for successful correction of Class II malocclusion. PowerScope provides the best results for Class II management, thus enables us to treat such cases by a nonextraction approach rather than contemplating extractions. PMID:27307671

  19. Mutant MHC class II epitopes drive therapeutic immune responses to cancer

    PubMed Central

    Kreiter, Sebastian; Vormehr, Mathias; van de Roemer, Niels; Diken, Mustafa; Löwer, Martin; Diekmann, Jan; Boegel, Sebastian; Schrörs, Barbara; Vascotto, Fulvia; Castle, John C.; Tadmor, Arbel D.; Schoenberger, Stephen P.; Huber, Christoph; Türeci, Özlem; Sahin, Ugur

    2016-01-01

    Tumour-specific mutations are ideal targets for cancer immunotherapy as they lack expression in healthy tissues and can potentially be recognized as neo-antigens by the mature T-cell repertoire. Their systematic targeting by vaccine approaches, however, has been hampered by the fact that every patient’s tumour possesses a unique set of mutations (‘the mutanome’) that must first be identified. Recently, we proposed a personalized immunotherapy approach to target the full spectrum of a patient’s individual tumour-specific mutations1. Here we show in three independent murine tumour models that a considerable fraction of non-synonymous cancer mutations is immunogenic and that, unexpectedly, the majority of the immunogenic mutanome is recognized by CD4+ T cells. Vaccination with such CD4+ immunogenic mutations confers strong antitumour activity. Encouraged by these findings, we established a process by which mutations identified by exome sequencing could be selected as vaccine targets solely through bioinformatic prioritization on the basis of their expression levels and major histocompatibility complex (MHC) class II-binding capacity for rapid production as synthetic poly-neo-epitope messenger RNA vaccines. We show that vaccination with such polytope mRNA vaccines induces potent tumour control and complete rejection of established aggressively growing tumours in mice. Moreover, we demonstrate that CD4+ T cell neo-epitope vaccination reshapes the tumour microenvironment and induces cytotoxic T lymphocyte responses against an independent immunodominant antigen in mice, indicating orchestration of antigen spread. Finally, we demonstrate an abundance of mutations predicted to bind to MHC class II in human cancers as well by employing the same predictive algorithm on corresponding human cancer types. Thus, the tailored immunotherapy approach introduced here may be regarded as a universally applicable blueprint for comprehensive exploitation of the substantial neo

  20. Linkage relationships and haplotype polymorphism among cichlid Mhc class II B loci.

    PubMed Central

    Málaga-Trillo, E; Zaleska-Rutczynska, Z; McAndrew, B; Vincek, V; Figueroa, F; Sültmann, H; Klein, J

    1998-01-01

    The species flocks of cichlid fishes in the Great East African Lakes are paradigms of adaptive radiation and hence, of great interest to evolutionary biologists. Phylogenetic studies of these fishes have, however, been hampered by the lack of suitable polymorphic markers. The genes of the major histocompatibility complex hold the promise to provide, through their extensive polymorphism, a large number of such markers, but their use has been hampered by the complexity of the genetic system and the lack of definition of the individual loci. In this study we take the first substantial step to alleviate this problem. Using a combination of methods, including the typing of single sperm cells, gyno- or androgenetic individuals, and haploid embryos, as well as sequencing of class II B restriction fragments isolated from gels for Southern blots, we identify the previously characterized homology groups as distinct loci. At least 17 polymorphic class II B loci, all of which are presumably transcribed, have been found among the different species studied. Most of these loci are shared across the various cichlid species and genera. The number of loci per haplotype varies from individual to individual, ranging from 1 to 13. A total of 21 distinct haplotypes differing in the number of loci they carry has thus far been identified. All the polymorphic loci are part of the same cluster in which, however, distances between at least some of the loci (as indicated by recombination frequencies) are relatively large. Both the individual loci and the haplotypes can now be used to study phylogenetic relationships among the members of the species flocks and the mode in which speciation occurs during adaptive radiation. PMID:9649539

  1. Interspecific hybridization increases MHC class II diversity in two sister species of newts.

    PubMed

    Nadachowska-Brzyska, Krystyna; Zieliński, Piotr; Radwan, Jacek; Babik, Wiesław

    2012-02-01

    Our understanding of the evolutionary mechanisms generating variation within the highly polymorphic major histocompatibility complex (MHC) genes remains incomplete. Assessing MHC variation across multiple populations, of recent and ancient divergence, may facilitate understanding of geographical and temporal aspects of variation. Here, we applied 454 sequencing to perform a large-scale, comprehensive analysis of MHC class II in the closely related, hybridizing newts, Lissotriton vulgaris (Lv) and Lissotriton montandoni (Lm). Our study revealed an extensive (299 alleles) geographically structured polymorphism. Populations at the southern margin of the Lv distribution, inhabited by old and distinct lineages (southern Lv), exhibited moderate MHC variation and strong population structure, indicating little gene flow or extensive local adaptation. Lissotriton vulgaris in central Europe and the northern Balkans (northern Lv) and almost all Lm populations had a high MHC variation. A much higher proportion of MHC alleles was shared between Lm and northern Lv than between Lm and southern Lv. Strikingly, the average pairwise F(ST) between northern Lv and Lm was significantly lower than between northern and southern Lv for MHC, but not for microsatellites. Thus, high MHC variation in Lm and northern Lv may result from gene flow between species. We hypothesize that the interspecific exchange of MHC genes may be facilitated by frequency-dependent selection. A marginally significant correlation between the MHC and microsatellite allelic richness indicates that demographic factors may have contributed to the present-day pattern of MHC variation, but unequivocal signatures of adaptive evolution in MHC class II sequences emphasize the role of selection on a longer timescale.

  2. MHC class II transcription is associated with inflammatory responses in a wild marine mammal.

    PubMed

    Montano-Frías, Jorge E; Vera-Massieu, Camila; Álvarez-Martínez, Roberto; Flores-Morán, Adriana; Acevedo-Whitehouse, Karina

    2016-08-01

    Inflammation is one of the most important non-specific and rapid responses that a vertebrate can elicit in response to damage or a foreign insult. To date, despite increasing evidence that the innate and adaptive branches of immunity are more intricately related than previously thought, few have examined interactions between the Major Histocompatibility Complex (MHC, a polymorphic region of the vertebrate genome that is involved with antigen presentation) and inflammation, and even less is known about these interactions in an eco-immunological context. Here, we examined the effect of MHC class II DRB gene multiplicity and transcription on phytohemagglutinin (PHA)-induced inflammation during the early stages of development of California sea lions. Neither constitutive nor expressed ZacaDRB diversity was found to be associated with pup responses to PHA at any of the stages of pup development. However, for two-month-old pups, those with a specific MHC-DRB locus (ZacaDRB-A) tended to have less efficient responsive inflammation. Transcription of distinct MHC-DRB loci was also linked to PHA-induced inflammation, with patterns that varied markedly between ages, and that suggested that ongoing infectious processes could limit the capacity to respond to a secondary challenge. Life history constraints and physiological processes associated with development of California sea lions, in conjunction with their changing pathogenic environment could explain the observed effects of MHC class II transcription on PHA-induced inflammation. To our knowledge, ours is the first study to examine the importance of expressed vs. constitutive MHC loci on inflammation in a natural population. PMID:27137083

  3. Cloning and characterization of a new swine MHC (SLA) class II DQB allele.

    PubMed

    Hosokawa, T; Tanioka, Y; Tanigawa, M; Matsumoto, Y; Onodera, T; Matsumoto, Y

    1998-06-01

    Major histocompatibility complex (MHC) of pigs is known as swine leukocyte antigen (SLA). The cDNA encoding a new allele of SLA class II DQ beta-chain was successfully isolated from a CSK miniature pig (derived from Göttingen strain) and characterized by sequence analyses. SLA-DQB cDNA fragment encoding beta 2-domain was amplified by reverse transcriptase-polymerase chain reaction using the sequences preserved in a various vertebrates as primers. Using non-radioisotope technique with the PCR product as a probe, cDNA clone G01 was isolated from a spleen cDNA library, and nucleotide sequence of this clone was determined. This clone encompassed a whole SLA-DQ beta-chain coding region, containing a total length of 1161 nucleotides with an open reading frame (ORF) of 786 nucleotides, 5' untranslated region of 15 nucleotides, and 3' untranslated region of 360 nucleotides ending with a canonical polyadenylation signal, followed by a poly A tail. Sequence comparisons of the ORF of this clone with those of known SLA-DQB genes confirmed that this clone is a new allele (SLA-DQB*G01). Phylogenetic analysis of the nucleotide sequences of swine, human, and murine MHC class II genes indicated that SLA-DQB was more similar to HLA-DQB1 than H-2A beta. Comparison of the nucleotide and deduced amino acid sequences among SLA-DQB alleles showed that the SLA-DQ beta-chain polymorphism was found almost in beta 1-domain which contains the antigenic peptide binding sites.

  4. Allelic diversity at class II DRB1 and DQB loci of the pig MHC (SLA).

    PubMed

    Kanai, T H; Tanioka, Y; Tanigawa, M; Matsumoto, Y; Ueda, S; Onodera, T; Matsumoto, Y

    1999-12-01

    The loci encoding the beta chain of the pig major histocompatibility complex (MHC) class II antigens, SLA-DR and -DQ, have been known to exhibit a remarkable degree of allelic polymorphism. Here, to understand the generation of SLA class II polymorphism, 25 SLA-DRB1 and 24 SLA-DQB genes including newly identified 12 SLA-DRB1 and 7 SLA-DQB genes obtained from miniature pigs were analyzed based on the nucleotide and deduced amino acid sequences. Most of the allelic diversity was attributed to the variable sequences which encode a beta1 domain consisting of a beta-pleated sheet followed by an a helix. In the beta1 domain coding region, there were four GC-rich sequences, which have been considered to involve the intra-exon sequence exchange also in other gene evolutions. The first and second GC-rich sequences were alpha-like sequences, which have been shown to be a putative recombination signal, and were stably conserved among SLA-DRB1 and DQB genes. These alpha-like sequences identified in SLA-DRB1 and SLA-DQB were found to encode the first turning point of the beta-pleated sheet and the boundary between the beta-pleated sheet and the alpha helix. Analysis of clustered sequence variation also suggested intra-exon gene conversions in which the alpha-like sequences act as putative breakpoints. In addition to point mutations and selection mechanism, intra-exon gene conversions must be an important mechanism in the generation of allelic polymorphism at the SLA-DRB1 and SLA-DQB.

  5. Large-scale MHC class II genotyping of a wild lemur population by next generation sequencing.

    PubMed

    Huchard, Elise; Albrecht, Christina; Schliehe-Diecks, Susanne; Baniel, Alice; Roos, Christian; Kappeler, Peter M; Peter, Peter M Kappeler; Brameier, Markus

    2012-12-01

    The critical role of major histocompatibility complex (MHC) genes in disease resistance, along with their putative function in sexual selection, reproduction and chemical ecology, make them an important genetic system in evolutionary ecology. Studying selective pressures acting on MHC genes in the wild nevertheless requires population-wide genotyping, which has long been challenging because of their extensive polymorphism. Here, we report on large-scale genotyping of the MHC class II loci of the grey mouse lemur (Microcebus murinus) from a wild population in western Madagascar. The second exons from MHC-DRB and -DQB of 772 and 672 individuals were sequenced, respectively, using a 454 sequencing platform, generating more than 800,000 reads. Sequence analysis, through a stepwise variant validation procedure, allowed reliable typing of more than 600 individuals. The quality of our genotyping was evaluated through three independent methods, namely genotyping the same individuals by both cloning and 454 sequencing, running duplicates, and comparing parent-offspring dyads; each displaying very high accuracy. A total of 61 (including 20 new) and 60 (including 53 new) alleles were detected at DRB and DQB genes, respectively. Both loci were non-duplicated, in tight linkage disequilibrium and in Hardy-Weinberg equilibrium, despite the fact that sequence analysis revealed clear evidence of historical selection. Our results highlight the potential of 454 sequencing technology in attempts to investigate patterns of selection shaping MHC variation in contemporary populations. The power of this approach will nevertheless be conditional upon strict quality control of the genotyping data.

  6. Single-Molecule Motions of MHC Class II Rely on Bound Peptides

    PubMed Central

    Kozono, Haruo; Matsushita, Yufuku; Ogawa, Naoki; Kozono, Yuko; Miyabe, Toshihiro; Sekiguchi, Hiroshi; Ichiyanagi, Kouhei; Okimoto, Noriaki; Taiji, Makoto; Kanagawa, Osami; Sasaki, Yuji C.

    2015-01-01

    The major histocompatibility complex (MHC) class II protein can bind peptides of different lengths in the region outside the peptide-binding groove. Peptide-flanking residues (PFRs) contribute to the binding affinity of the peptide for MHC and change the immunogenicity of the peptide/MHC complex with regard to T cell receptor (TCR). The mechanisms underlying these phenomena are currently unknown. The molecular flexibility of the peptide/MHC complex may be an important determinant of the structures recognized by certain T cells. We used single-molecule x-ray analysis (diffracted x-ray tracking (DXT)) and fluorescence anisotropy to investigate these mechanisms. DXT enabled us to monitor the real-time Brownian motion of the peptide/MHC complex and revealed that peptides without PFRs undergo larger rotational motions than peptides with PFRs. Fluorescence anisotropy further revealed that peptides without PFRs exhibit slightly larger motions on the nanosecond timescale. These results demonstrate that peptides without PFRs undergo dynamic motions in the groove of MHC and consequently are able to assume diverse structures that can be recognized by T cells. PMID:25606683

  7. MHC class II B diversity in blue tits: a preliminary study

    PubMed Central

    Aguilar, Juan Rivero-de; Schut, Elske; Merino, Santiago; Martínez, Javier; Komdeur, Jan; Westerdahl, Helena

    2013-01-01

    In this study, we partly characterize major histocompatibility complex (MHC) class II B in the blue tit (Cyanistes caeruleus). A total of 22 individuals from three different European locations: Spain, The Netherlands, and Sweden were screened for MHC allelic diversity. The MHC genes were investigated using both PCR-based methods and unamplified genomic DNA with restriction fragment length polymorphism (RFLP) and southern blots. A total of 13 different exon 2 sequences were obtained independently from DNA and/or RNA, thus confirming gene transcription and likely functionality of the genes. Nine out of 13 alleles were found in more than one country, and two alleles appeared in all countries. Positive selection was detected in the region coding for the peptide binding region (PBR). A maximum of three alleles per individual was detected by sequencing and the RFLP pattern consisted of 4–7 fragments, indicating a minimum number of 2–4 loci per individual. A phylogenetic analysis, demonstrated that the blue tit sequences are divergent compared to sequences from other passerines resembling a different MHC lineage than those possessed by most passerines studied to date. PMID:23919136

  8. Polymorphisms at MHC class II DRB1 exon 2 locus in Pyrenean chamois (Rupicapra pyrenaica pyrenaica).

    PubMed

    Cavallero, Serena; Marco, Ignasi; Lavín, Santiago; D'Amelio, Stefano; López-Olvera, Jorge R

    2012-07-01

    Chamois (Rupicapra spp.) are mountain ungulates from Southern and Central Europe and the Near East. A newly reported border disease virus (BDV) has affected the easternmost populations of Pyrenean chamois, leading to a dramatic population decrease that may drive to genetic variability loss. The Major Histocompatibility Complex (MHC) is a sensitive marker for genetic variation of populations: polymorphism on the MHC genes is affected both by pathogens and population dynamics and it is ecologically relevant, as depending on host-pathogen relationships and life history features. In the present study MHC class II DRB1 exon 2 variation was investigated in 81 Pyrenean chamois (Rupicapra pyrenaica pyrenaica) belonging to four populations. Haplotype analysis, population genetics statistics and network analysis were carried out, in order to analyze variability, phylogeography and genealogy, and the effects of geography and demographic trend. Twenty-nine haplotypes were identified, 26 of them newly described, with high Gene diversity (Gd). The variability observed in the easternmost populations of Pyrenean chamois showed a higher genetic diversity than that previously reported for other populations of Pyrenean and Cantabrian chamois (Rupicapra pyrenaica parva). The most frequent allele was RupyDRB*15, previously undetected, which seems to play a significant role in genotyping the variability, suggesting a possible effect of positive selection. PMID:22425496

  9. ITAM signaling in dendritic cells controls T helper cell priming by regulating MHC class II recycling

    PubMed Central

    Graham, Daniel B.; Akilesh, Holly M.; Gmyrek, Grzegorz B.; Piccio, Laura; Gilfillan, Susan; Sim, Julia; Belizaire, Roger; Carrero, Javier A.; Wang, Yinan; Blaufuss, Gregory S.; Sandoval, Gabriel; Fujikawa, Keiko; Cross, Anne H.; Russell, John H.; Cella, Marina

    2010-01-01

    Immature dendritic cells (DCs) specialize in antigen capture and maintain a highly dynamic pool of intracellular major histocompatibility complex class II (MHCII) that continuously recycles from peptide loading compartments to the plasma membrane and back again. This process facilitates sampling of environmental antigens for presentation to T helper cells. Here, we show that a signaling pathway mediated by the DC immunoreceptor tyrosine-based activation motif (ITAM)–containing adaptors (DAP12 and FcRγ) and Vav family guanine nucleotide exchange factors controls the half-life of surface peptide-MHCII (pMHCII) complexes and is critical for CD4 T-cell triggering in vitro. Strikingly, mice with disrupted DC ITAMs show defective T helper cell priming in vivo and are protected from experimental autoimmune encephalitis. Mechanistically, we show that deficiency in ITAM signaling results in increased pMHCII internalization, impaired recycling, and an accumulation of ubiquitinated MHCII species that are prematurely degraded in lysosomes. We propose a novel mechanism for control of T helper cell priming. PMID:20634378

  10. Yeast surface display of a noncovalent MHC class II heterodimer complexed with antigenic peptide.

    PubMed

    Boder, Eric T; Bill, Jerome R; Nields, Andrew W; Marrack, Philippa C; Kappler, John W

    2005-11-20

    Microbial protein display technologies have enabled directed molecular evolution of binding and stability properties in numerous protein systems. In particular, dramatic improvements to antibody binding affinity and kinetics have been accomplished using these tools in recent years. Examples of successful application of display technologies to other immunological proteins have been limited to date. Herein, we describe the expression of human class II major histocompatibility complex allele (MHCII) HLA-DR4 on the surface of Saccharomyces cerevisiae as a noncovalently associated heterodimer. The yeast-displayed MHCII is fully native as assessed by binding of conformationally specific monoclonal antibodies; failure of antibodies specific for empty HLA-DR4 to bind yeast-displayed protein indicates antigenic peptide is bound. This report represents the first example of a noncovalent protein dimer displayed on yeast and of successful display of wild-type MHCII. Results further point to the potential for using yeast surface display for engineering and analyzing the antigen binding properties of MHCII.

  11. Cell surface display of functional human MHC class II proteins: yeast display versus insect cell display

    PubMed Central

    Wen, Fei; Sethi, Dhruv K.; Wucherpfennig, Kai W.; Zhao, Huimin

    2011-01-01

    Reliable and robust systems for engineering functional major histocompatibility complex class II (MHCII) proteins have proved elusive. Availability of such systems would enable the engineering of peptide-MHCII (pMHCII) complexes for therapeutic and diagnostic applications. In this paper, we have developed a system based on insect cell surface display that allows functional expression of heterodimeric DR2 molecules with or without a covalently bound human myelin basic protein (MBP) peptide, which is amenable to directed evolution of DR2–MBP variants with improved T cell receptor (TCR)-binding affinity. This study represents the first example of functional display of human pMHCII complexes on insect cell surface. In the process of developing this pMHCII engineering system, we have also explored the potential of using yeast surface display for the same application. Our data suggest that yeast display is a useful system for analysis and engineering of peptide binding of MHCII proteins, but not suitable for directed evolution of pMHC complexes that bind with low affinity to self-reactive TCRs. PMID:21752831

  12. Airway in Class I and Class II skeletal pattern: A computed tomography study

    PubMed Central

    Paul, Deepthi; Varma, Sapna; Ajith, V. V.

    2015-01-01

    Background and Objectives: A normal airway is required for the normal growth of the craniofacial structures. The present study was designed to evaluate and compare the airway in Class I and Class II skeletal pattern and to see if there is any association between the airway and maxillomandibular relationship. Materials and Methods: Peripheral nervous system computed tomography scans of 30 patients were divided into two groups as Class I (ANB ≤ 4.5°), Class II (ANB ≥ 4.5°). The Dolphin three-dimensional version 11 was used to assess the airway. Statistical Analysis: Correlations between the variables were tested with the Pearson correlation coefficient. Independent sample t-test was performed to compare the averages between the two groups. P < 0.05 was considered as statistically significant. Results: The ANB angle was negatively correlated with all the airway parameters. The airway area and volume was significantly reduced in Class II subjects compared to Class I. Conclusion: The results suggest a strong association between the airway and skeletal pattern showing a reduced airway in Class II patients with a high ANB angle. PMID:26321823

  13. Phylogenetic relationships of class II fumarase genes from trichomonad species.

    PubMed

    Gerbod, D; Edgcomb, V P; Noël, C; Vanácová, S; Wintjens, R; Tachezy, J; Sogin, M L; Viscogliosi, E

    2001-08-01

    Class II fumarase sequences were obtained by polymerase chain reaction from five trichomonad species. All residues known to be highly conserved in this enzyme were present. Nuclear run-on assays showed that one of the two genes identified in Tritrichomonas foetus was expressed, whereas no fumarase transcripts were detected in the related species Trichomonas vaginalis. These findings corroborate previous biochemical data. Fumarase genes were also expressed in Monocercomonas sp. and Tetratrichomonas gallinarum but not in Pentatrichomonas hominis, Trichomonas gallinae, Trichomonas tenax, and Trichomitus batrachorum under the culture conditions used. Molecular trees inferred by likelihood methods reveal that trichomonad sequences have no affinity to described class II fumarase genes from other eukaryotes. The absence of functional mitochondria in protists such as trichomonads suggests that they diverged from other eukaryotes prior to the alpha-proteobacterial symbiosis that led to mitochondria. Furthermore, they are basal to other eukaryotes in rRNA analyses. However, support for the early-branching status of trichomonads and other amitochondriate protists based on phylogenetic analyses of multiple data sets has been equivocal. Although the presence of hydrogenosomes suggests that trichomonads once had mitochondria, their class II iron-independent fumarase sequences differ markedly from those of other mitochondriate eukaryotes. All of the class II fumarase genes described from other eukaryotes are of apparent alpha-proteobacterial origin and hence a marker of mitochondrial evolution. In contrast, the class II fumarase from trichomonads emerges among other eubacterial homologs. This is intriguing evidence for an independent acquisition of these genes in trichomonads apart from the mitochondrial endosymbiosis event that gave rise to the form present in other eukaryotes. The ancestral trichomonad class II fumarase may represent a prokaryotic form that was replaced in

  14. Phylogenetic relationships of class II fumarase genes from trichomonad species.

    PubMed

    Gerbod, D; Edgcomb, V P; Noël, C; Vanácová, S; Wintjens, R; Tachezy, J; Sogin, M L; Viscogliosi, E

    2001-08-01

    Class II fumarase sequences were obtained by polymerase chain reaction from five trichomonad species. All residues known to be highly conserved in this enzyme were present. Nuclear run-on assays showed that one of the two genes identified in Tritrichomonas foetus was expressed, whereas no fumarase transcripts were detected in the related species Trichomonas vaginalis. These findings corroborate previous biochemical data. Fumarase genes were also expressed in Monocercomonas sp. and Tetratrichomonas gallinarum but not in Pentatrichomonas hominis, Trichomonas gallinae, Trichomonas tenax, and Trichomitus batrachorum under the culture conditions used. Molecular trees inferred by likelihood methods reveal that trichomonad sequences have no affinity to described class II fumarase genes from other eukaryotes. The absence of functional mitochondria in protists such as trichomonads suggests that they diverged from other eukaryotes prior to the alpha-proteobacterial symbiosis that led to mitochondria. Furthermore, they are basal to other eukaryotes in rRNA analyses. However, support for the early-branching status of trichomonads and other amitochondriate protists based on phylogenetic analyses of multiple data sets has been equivocal. Although the presence of hydrogenosomes suggests that trichomonads once had mitochondria, their class II iron-independent fumarase sequences differ markedly from those of other mitochondriate eukaryotes. All of the class II fumarase genes described from other eukaryotes are of apparent alpha-proteobacterial origin and hence a marker of mitochondrial evolution. In contrast, the class II fumarase from trichomonads emerges among other eubacterial homologs. This is intriguing evidence for an independent acquisition of these genes in trichomonads apart from the mitochondrial endosymbiosis event that gave rise to the form present in other eukaryotes. The ancestral trichomonad class II fumarase may represent a prokaryotic form that was replaced in

  15. Plastid Class I and Cytosol Class II Aldolase of Euglena gracilis (Purification and Characterization).

    PubMed Central

    Pelzer-Reith, B.; Wiegand, S.; Schnarrenberger, C.

    1994-01-01

    The plastidic class I and cytosolic class II aldolases of Euglena gracilis have been purified to apparent homogeneity. In autotrophically grown cells, up to 81% of the total activity is due to class I activity, whereas in heterotrophically grown cells, it is only 7%. The class I aldolase has been purified to a specific activity of 20 units/mg protein by anion-exchange chromatography, affinity chromatography, and gel filtration. The native enzyme (molecular mass 160 kD) consisted of four identical subunits of 40 kD. The class II aldolase was purified to a specific activity of 21 units/mg by (NH4)2SO4 fractionation, anion-exchange chromatography, chromatography on hydroxylapatite, and gel filtration. The native enzyme (molecular mass 80 kD) consisted of two identical subunits of 38 kD. The Km (fructose-1,6-bisphosphate) values were 12 [mu]M for the class I enzyme and 175 [mu]M for the class II enzyme. The class II aldolase was inhibited by 1 mM ethylenediaminetetraacetate (EDTA), 0.8 mM cysteine, 0.5 mM Zn2+, or 0.5 mM Cu2+. Na+, K+, Rb+, and NH4+ (but not Li+ or Cs+) enhanced the activity up to 7-fold. After inactivation by EDTA, the activity could be partially restored by Mn2+, Cu2+, or Co2+. A subclassification of class II aldolases is proposed based on (a) activation/inhibition by Cys and (b) activation or not by divalent ions. PMID:12232396

  16. In vitro digestion with proteases producing MHC class II ligands.

    PubMed

    Tohmé, Mira; Maschalidi, Sophia; Manoury, Bénédicte

    2013-01-01

    Proteases generate peptides that bind to MHC class II molecules to interact with a wide diversity of CD4(+) T cells. They are expressed in dedicated organelles: endosomes and lysosomes of professional antigen presenting cells (pAPCs) such as B cells, macrophages, and dendritic cells. The identification of endosomal proteases which produce antigenic peptides is important, for example, for better vaccination and to prevent autoimmune diseases. Here, we describe a panel of technics (in vitro digestion assays of protein with recombinant proteases or purified endosomes/lysosomes, T cell stimulation) to monitor the production of MHC class II ligands. PMID:23329510

  17. An innovative approach to Class II preparation and restoration.

    PubMed

    Haase, S L

    1998-01-01

    When patients exhibit Class II defects requiring restoration, the treatment modality and respective preparation requirements may present challenges to the clinician. Aesthetics, chairside time, and expense become factors for the consideration of both dentist and patient. However, a new sonically driven system for the preparation and restoration of proximal defects was recently introduced (SONICSYS, Ivoclar Vivadent, Amherst, NY). This system, composed of diamond-coated tips and prefabricated ceramic inserts, promises to enable clinicians to efficiently, confidently, and expertly prepare and restore Class II defects in a timely, consistent, and cost-efficient manner. This article describes the components of the system and demonstrates its utilization in a case report.

  18. Mice lacking all conventional MHC class II genes

    PubMed Central

    Madsen, Lars; Labrecque, Nathalie; Engberg, Jan; Dierich, Andrée; Svejgaard, Arne; Benoist, Christophe; Mathis, Diane; Fugger, Lars

    1999-01-01

    MHC class II (MHC-II) molecules play a central role in the selection of the T cell repertoire, in the establishment and regulation of the adaptive immune response, and in autoimmune deviation. We have generated knockout mice lacking all four of the classical murine MHC-II genes (MHCIIΔ/Δ mice), via a large (80-kilobase) deletion of the entire class II region that was engineered by homologous recombination and Cre recombinase-mediated excision. These mice feature immune system perturbations like those of Aα and Aβ knockout animals, notably a dearth of CD4+ lymphocytes in the thymus and spleen. No new anatomical or physiological abnormalities were observed in MHCIIΔ/Δ mice. Because these animals are devoid of all classical MHC-II chains, even unpaired chains, they make excellent recipients for MHC-II transgenes from other species, avoiding the problem of interspecies cross-pairing of MHC-II chains. Therefore, they should be invaluable for engineering “humanized” mouse models of human MHC-II-associated autoimmune disorders. PMID:10468609

  19. 40 CFR 147.3400 - Navajo Indian lands-Class II wells.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Navajo Indian lands-Class II wells... Indian Lands § 147.3400 Navajo Indian lands—Class II wells. The UIC program for Class II injection wells... granted the Navajo Nation primacy for the SDWA Class II UIC program”), is the program administered by...

  20. 40 CFR 147.3400 - Navajo Indian lands-Class II wells.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Navajo Indian lands-Class II wells... Indian Lands § 147.3400 Navajo Indian lands—Class II wells. The UIC program for Class II injection wells... granted the Navajo Nation primacy for the SDWA Class II UIC program”), is the program administered by...

  1. CIITA promoter I CARD-deficient mice express functional MHC class II genes in myeloid and lymphoid compartments.

    PubMed

    Zinzow-Kramer, W M; Long, A B; Youngblood, B A; Rosenthal, K M; Butler, R; Mohammed, A-U-R; Skountzou, I; Ahmed, R; Evavold, B D; Boss, J M

    2012-06-01

    Three distinct promoters control the master regulator of major histocompatibility complex (MHC) class II expression, class II transactivator (CIITA), in a cell type-specific manner. Promoter I (pI) CIITA, expressed primarily by dendritic cells (DCs) and macrophages, expresses a unique isoform that contains a caspase-recruitment domain (CARD). The activity and function of this isoform are not understood, but are believed to enhance the function of CIITA in antigen-presenting cells. To determine whether isoform I of CIITA has specific functions, CIITA mutant mice were created in which isoform I was replaced with isoform III sequences. Mice in which pI and the CARD-encoding exon were deleted were also created. No defect in the formation of CD4 T cells, the ability to respond to a model antigen or bacterial or viral challenge was observed in mice lacking CIITA isoform I. Although CIITA and MHC-II expression was decreased in splenic DCs, pI knockout animals expressed CIITA from downstream promoters, suggesting that control of pI activity is mediated by unknown distal elements that could act at pIII, the B-cell promoter. Thus, no critical function is linked to the CARD domain of CIITA isoform I with respect to basic immune system development, function and challenge.

  2. MHC Class II-Restricted Presentation of the Major House Dust Mite Allergen Der p 1 Is GILT-Dependent: Implications for Allergic Asthma

    PubMed Central

    West, Laura Ciaccia; Grotzke, Jeff E.; Cresswell, Peter

    2013-01-01

    Gamma-interferon-inducible lysosomal thiol reductase (GILT) is known to reduce disulfide bonds present in proteins internalized by antigen presenting cells, facilitating optimal processing and presentation of peptides on Major Histocompatibility Complex class II molecules, as well as the subsequent activation of CD4-positive T lymphocytes. Here, we show that GILT is required for class II-restricted processing and presentation of immunodominant epitopes from the major house dust mite allergen Der p 1. In the absence of GILT, CD4-positive T cell responses to Der p 1 are significantly reduced, resulting in mitigated allergic airway inflammation in response to Der p 1 and house dust mite extracts in a murine model of asthma. PMID:23326313

  3. MHC class II DR allelic diversity in bighorn sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We hypothesized that decreased diversity and/or unique polymorphisms in MHC class II alleles of bighorn sheep (BHS, Ovis canadensis) are responsible for lower titer of antibodies against Mannheimia haemolytica leukotoxin, in comparison to domestic sheep (DS, Ovis aries). To test this hypothesis, DRA...

  4. Class II malocclusion nonextraction treatment with growth control*

    PubMed Central

    Assunção, Zilda Lúcia Valentim

    2014-01-01

    The present study reports a case of Angle Class II malocclusion treatment of a male growing patient with 10-mm overjet, excessive overbite and transverse maxillary deficiency. The case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO), with DI equal to or greater than 10, as a requirement for the title of certified by the BBO. PMID:25628088

  5. HLA class II and autoimmunity: epitope selection vs differential expression.

    PubMed

    Müller-Hilke, Brigitte

    2009-01-01

    Autoimmune diseases like rheumatoid arthritis (RA), multiple sclerosis, psoriasis and insulin-dependent diabetes mellitus are subject to a complex pathogenesis controlled by multiple genes and numerous environmental factors. The strongest genetic association is with certain HLA class II haplotypes and we here summarize the evidence supporting differential expression as a mechanism supporting the autoimmune process. PMID:19118870

  6. 18 CFR 415.21 - Class II projects.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Class II projects. 415.21 Section 415.21 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-FLOOD PLAIN REGULATIONS Types of Projects and Jurisdiction § 415.21...

  7. Predicting promiscuous antigenic T cell epitopes of Mycobacterium tuberculosis mymA operon proteins binding to MHC Class I and Class II molecules.

    PubMed

    Saraav, Iti; Pandey, Kirti; Sharma, Monika; Singh, Swati; Dutta, Prasun; Bhardwaj, Anshu; Sharma, Sadhna

    2016-10-01

    Limited efficacy of Bacillus Calmette-Guérin vaccine has raised the need to explore other immunogenic candidates to develop an effective vaccine against Mycobacterium tuberculosis (Mtb). Both CD4+ and CD8+ T cells play a critical role in host immunity to Mtb. Infection of macrophages with Mtb results in upregulation of mymA operon genes thereby suggesting their importance as immune targets. In the present study, after exclusion of self-peptides mymA operon proteins of Mtb were analyzed in silico for the presence of Human Leukocyte Antigen (HLA) Class I and Class II binding peptides using Bioinformatics and molecular analysis section, NetMHC 3.4, ProPred and Immune epitope database software. Out of 56 promiscuous epitopes obtained, 41 epitopes were predicted to be antigenic for MHC Class I. In MHC Class II, out of 336 promiscuous epitopes obtained, 142 epitopes were predicted to be antigenic. The comparative bioinformatics analysis of mymA operon proteins found Rv3083 to be the best vaccine candidate. Molecular docking was performed with the most antigenic peptides of Rv3083 (LASGAASVV with alleles HLA-B51:01, HAATSGTLI with HLA-A02, IVTATGLNI and EKIHYGLKVNTA with HLA-DRB1_01:01) to study the structural basis for recognition of peptides by various HLA molecules. The software binding prediction was validated by the obtained molecular docking score of peptide-HLA complex. These peptides can be further investigated for their immunological relevance in patients of tuberculosis using major histocompatibility complex tetramer approach. PMID:27389362

  8. The role of charge and multiple faces of the CD8 alpha/alpha homodimer in binding to major histocompatibility complex class I molecules: support for a bivalent model.

    PubMed Central

    Giblin, P A; Leahy, D J; Mennone, J; Kavathas, P B

    1994-01-01

    The CD8 dimer interacts with the alpha 3 domain of major histocompatibility complex class I molecules through two immunoglobulin variable-like domains. In this study a crystal structure-informed mutational analysis has been performed to identify amino acids in the CD8 alpha/alpha homodimer that are likely to be involved in binding to class I. Several key residues are situated on the top face of the dimer within loops analogous to the complementarity-determining regions (CDRs) of immunoglobulin. In addition, other important amino acids are located in the A and B beta-strands on the sides of the dimer. The potential involvement of amino acids on both the top and the side faces of the molecule is consistent with a bivalent model for the interaction between a single CD8 alpha/alpha homodimer and two class I molecules and may have important implications for signal transduction in class I-expressing cells. This study also demonstrates a role for the positive surface potential of CD8 in class I binding and complements previous work demonstrating the importance of a negatively charged loop on the alpha 3 domain of class I for CD8 alpha/alpha-class I interaction. We propose a model whereby residues located on the CDR-like loops of the CD8 homodimer interact with the alpha 3 domain of MHC class I while amino acids on the side of the molecule containing the A and B beta-strands contact the alpha 2 domain of class I. Images PMID:8127870

  9. Genotyping of black grouse MHC class II B using reference Strand-Mediated Conformational Analysis (RSCA)

    PubMed Central

    2011-01-01

    Background The Major Histocompatibility Complex (MHC) is a cluster of genes involved in the vertebrate immune system and includes loci with an extraordinary number of alleles. Due to the complex evolution of MHC genes, alleles from different loci within the same MHC class can be very similar and therefore difficult to assign to separate loci. Consequently, single locus amplification of MHC genes is hard to carry out in species with recently duplicated genes in the same MHC class, and multiple MHC loci have to be genotyped simultaneously. Since amplified alleles have the same length, accurate genotyping is difficult. Reference Strand-Mediated Conformational Analysis (RSCA), which is increasingly used in studies of natural populations with multiple MHC genes, is a genotyping method capable to provide high resolution and accuracy in such cases. Findings We adapted the RSCA method to genotype multiple MHC class II B (BLB) genes in black grouse (Tetrao tetrix), a non-model galliform bird species, using a 96-Capillary Array Electrophoresis, the MegaBACE™ 1000 DNA Analysing System (GE Healthcare). In this study we used fluorescently labelled reference strands from both black grouse and hazel grouse and observed good agreement between RSCA and cloning/sequencing since 71 alleles were observed by cloning/sequencing and 76 alleles by RSCA among the 24 individuals included in the comparison. At the individual level however, there was a trend towards more alleles scored with RSCA (1-6 per individual) than cloning/sequencing (1-4 per individual). In 63% of the pair-wise comparison, the identical allele was scored in RSCA as in cloning/sequencing. Nine out of 24 individuals had the same number of alleles in RSCA as in cloning/sequencing. Our RSCA protocol allows a faster RSCA genotyping than presented in many other RSCA studies. Conclusions In this study, we have developed the RSCA typing method further to work on a 96-Capillary Array Electrophoresis (MegaBACE™ 1000). Our

  10. Salmonella typhimurium delta aroA delta aroD mutants expressing a foreign recombinant protein induce specific major histocompatibility complex class I-restricted cytotoxic T lymphocytes in mice.

    PubMed Central

    Turner, S J; Carbone, F R; Strugnell, R A

    1993-01-01

    Recombinant Salmonella typhimurium aroA aroD mutants which expressed ovalbumin were constructed. The two expression constructs used were based on either pUC18 or pBR322. The pBR322-based construct was more stable in vitro and in vivo than the pUC-based construct. Salmonellae containing the stable pBR322-based plasmid induced major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes (CTL), in contrast to salmonellae containing the pUC18-based expression construct. The priming of MHC class I-restricted CTL was increased by multiple immunizations. The study described in this report suggest that S. typhimurium delta aro mutants have the capacity to induce MHC class I-restricted CTL against carried antigens and that MHC class I-restricted CTL responses require stable in vivo expression of the target antigen. Further, the results indicate that the Salmonella typhi delta aro mutants currently undergoing evaluation in studies with humans may be good carriers of viral antigens with CTL determinants. Images PMID:8225611

  11. Provocation of skin graft rejection across murine class II differences by non--bone-marrow-derived cells

    SciTech Connect

    Stuart, P.M.; Beck-Maier, B.; Melvold, R.W.

    1984-04-01

    We have evaluated the relative contribution of bone-marrow-derived cells to skin allograft immunogenicity in mice differing only at class II major histocompatibility genes by using bone marrow radiation chimeras as donors. The mouse strains used were C57BL/6Kh (B6) and B6.C-H-2bm12 (bm12), which differ only at at A beta gene of the I region of the mouse H-2 complex. Our results demonstrated that skin from (B6----bm12) chimeras was accepted by bm12 recipients and rejected by B6 mice in a manner indistinguishable from that of normal bm12 skin. Likewise, naive bm12 mice rejected (bm12----B6) chimeric skin and normal B6 skin equally well, and B6 animals accepted both types of skin grafts. Our data argues that the donor cell-type leading to graft rejection across limited I region differences is not of bone marrow origin, and that these cells must--at least under certain circumstances--express class II antigens.

  12. Molecular characterization of MHC class II in a nonmodel anuran species, the fire-bellied toad Bombina bombina.

    PubMed

    Hauswaldt, J Susanne; Stuckas, H; Pfautsch, S; Tiedemann, R

    2007-06-01

    While the anuran Xenopus comprises one of the best characterized nonmammalian taxa regarding the major histocompatibility complex (MHC), the organization of this gene complex has never been studied in other anurans, and information on amphibian MHC (other than Xenopus) is generally very scarce. Here, we describe the characterization of the first MHC class II B cDNA sequences from a nonmodel anuran species, the European fire-bellied toad (Bombina bombina). We isolated two transcript sequences differing substantially in amino acid composition and length within the beta2 domain. To investigate the variability of the peptide binding region in this species, we sequenced a 158-bp large fragment from wild B. bombina (n = 20) and identified eight distinct alleles. All substitutions but one were nonsynonymous, and many of the highly polymorphic sites corresponded with amino acid positions known to be involved in antigen binding. The level of variation we found in B. bombina was similar compared to that previously found in a comparable sample of a wild urodelan species, Ambystoma tigrinum, and to that found in Xenopus laevis. Based on the cDNA data and the individual's allelic diversity, we conclude that Bombina possesses at least two class II B loci. With our new beta1 primers, we were able to generate sequences in other species of anurans. We provide here a first phylogenetic analysis of this gene in amphibians.

  13. Direct enumeration of Borrelia-reactive CD4 T cells ex vivo by using MHC class II tetramers

    PubMed Central

    Meyer, Abbie L.; Trollmo, Christina; Crawford, Frances; Marrack, Philippa; Steere, Allen C.; Huber, Brigitte T.; Kappler, John; Hafler, David A.

    2000-01-01

    We characterized antigen-specific CD4+ T cells in six patients with treatment-resistant Lyme arthritis, using an HLA-DRB1*0401 major histocompatibility complex (MHC) class II tetramer covalently loaded with OspA164–175, an immunodominant epitope of Borrelia burgdorferi. Direct analysis of OspA-tetramer binding CD4+ cells in patients expressing the HLA-DRB1*0401 allele revealed frequencies of between <0.005 and 0.1% in peripheral blood (n = 6), and between <0.005 and 3.1% in synovial fluid (n = 3). OspA-tetramer+CD4+ cells were directly cloned at 1 cell per well and expanded by mitogen and IL-2 on allogeneic feeder cells. As measured by [3H]thymidine incorporation, 95% of 168 T cell clones from synovial fluid binding the OspA-tetramer were antigen-reactive. Clones generated from peripheral blood revealed a different pattern of responsiveness when compared with clones generated from synovial fluid, as measured by proliferation, IFN-γ, and IL-13 secretion. These clones, selected on the basis of their peptide binding, also responded to whole protein, but with a different cytokine profile. Our studies demonstrate that MHC class II tetramers can be used in humans to directly identify, isolate, and characterize antigen-reactive T cells from an inflammatory compartment. PMID:11005833

  14. Discordant patterns of linkage disequilibrium of the peptide-transporter loci within the HLA class II region

    SciTech Connect

    Klitz, W.; Grote, M.; Stephens, J.C.

    1995-12-01

    Disequilibrium between genetic markers is expected to decline monotonically with recombinational map distance. We present evidence from the HLA class II region that seems to violate this principle. Pairwise disequilibrium values were calculated for six loci ranging in physical separation from 15 kb to 550 kb. The histocompatibility loci DRB1, DQA1, and DQBI, located on the distal end of the class II region, behave as a single evolutionary unit within which extremely high linkage disequilibrium exists. Lower but still significant levels of disequilibrium are present between these loci and DPB1, located at the proximal edge of the HLA complex. The peptide-transporter loci TAP1 and TAP2, located in the intervening region, reveal no disequilibrium with each other and low or negligible disequilibrium with the flanking loci. The action of two genetic processes is required to account for this phenomenon: a recombinational hotspot operating between TAP1 and TAP2, to eliminate disequilibrium between these loci, and at the same time selection operating on particular combinations of alleles across the DR-DP region, to create disequilibrium in the favored haplotypes. The forces producing the patterns of disequilibrium observed here have implications for the mapping of trait loci and disease genes: markers of TAP1, for example, would give a false impression as to the influence of DPB1 on a trait known to be associated with DQB1. 44 refs., 2 figs., 3 tabs.

  15. Tissue-specific, inducible and functional expression of the E alpha d MHC class II gene in transgenic mice.

    PubMed Central

    Pinkert, C A; Widera, G; Cowing, C; Heber-Katz, E; Palmiter, R D; Flavell, R A; Brinster, R L

    1985-01-01

    We have introduced the class II E alpha d gene into (C57BL/6 X SJL) F2 mice which do not express their endogenous E alpha gene. The mRNA expression of the E alpha d gene shows the same tissue distribution as the endogenous class II genes except in the case of one mouse, which carried 19 copies of the E alpha d gene. In this mouse expression of E alpha d mRNA was seen in all tissues tested. Expression of the transgene was induced by gamma-interferon in isolated macrophages from the transgenic mice. In addition, fluorescence activated cell sorter (FACS) analysis, mixed lymphocyte response and antigen-presentation experiments showed that the product of the transferred gene is expressed on the cell surface and functions as a major histocompatibility complex restriction element. Transmission of the gene occurred only with female transgenic mice, all males were infertile or did not transmit the gene, suggesting an effect of the transferred DNA sequence on male reproductive function. Images Fig. 2. PMID:3935430

  16. Amino Acid Variation in HLA Class II Proteins Is a Major Determinant of Humoral Response to Common Viruses

    PubMed Central

    Hammer, Christian; Begemann, Martin; McLaren, Paul J.; Bartha, István; Michel, Angelika; Klose, Beate; Schmitt, Corinna; Waterboer, Tim; Pawlita, Michael; Schulz, Thomas F.; Ehrenreich, Hannelore; Fellay, Jacques

    2015-01-01

    The magnitude of the human antibody response to viral antigens is highly variable. To explore the human genetic contribution to this variability, we performed genome-wide association studies of the immunoglobulin G response to 14 pathogenic viruses in 2,363 immunocompetent adults. Significant associations were observed in the major histocompatibility complex region on chromosome 6 for influenza A virus, Epstein-Barr virus, JC polyomavirus, and Merkel cell polyomavirus. Using local imputation and fine mapping, we identified specific amino acid residues in human leucocyte antigen (HLA) class II proteins as the most probable causal variants underlying these association signals. Common HLA-DRβ1 haplotypes showed virus-specific patterns of humoral-response regulation. We observed an overlap between variants affecting the humoral response to influenza A and EBV and variants previously associated with autoimmune diseases related to these viruses. The results of this study emphasize the central and pathogen-specific role of HLA class II variation in the modulation of humoral immune response to viral antigens in humans. PMID:26456283

  17. 25 CFR 522.11 - Individually owned class II gaming operations operating on September 1, 1986.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.11 Individually owned class II gaming operations operating on September 1... 25 Indians 2 2010-04-01 2010-04-01 false Individually owned class II gaming operations...

  18. 25 CFR 522.11 - Individually owned class II gaming operations operating on September 1, 1986.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.11 Individually owned class II gaming operations operating on September 1... 25 Indians 2 2014-04-01 2014-04-01 false Individually owned class II gaming operations...

  19. 25 CFR 522.11 - Individually owned class II gaming operations operating on September 1, 1986.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.11 Individually owned class II gaming operations operating on September 1... 25 Indians 2 2011-04-01 2011-04-01 false Individually owned class II gaming operations...

  20. 25 CFR 522.11 - Individually owned class II gaming operations operating on September 1, 1986.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.11 Individually owned class II gaming operations operating on September 1... 25 Indians 2 2013-04-01 2013-04-01 false Individually owned class II gaming operations...

  1. 25 CFR 522.11 - Individually owned class II gaming operations operating on September 1, 1986.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.11 Individually owned class II gaming operations operating on September 1... 25 Indians 2 2012-04-01 2012-04-01 false Individually owned class II gaming operations...

  2. Evaluation of arch width among Class I normal occlusion, Class II Division 1, Class II Division 2, and Class III malocclusion in Indian population

    PubMed Central

    Patel, Dolly; Mehta, Falguni; Patel, Nimesh; Mehta, Nishit; Trivedi, Ipist; Mehta, Apexa

    2015-01-01

    Objective: To test the hypothesis that there is no difference between Class I (CI) normal occlusion, Class II division 1 (CIId1) and CII division 2 (CIId2), and Class III (CIII) malocclusion with respect to arch widths, width of the maxillary and mandibular arches, gender dimorphism within groups, and gender comparisons. Materials and Methods: Samples of 40 CI subjects, 40 CIId1 subjects, 40 CIId2 subjects, and 34 CIII subjects were studied. All subjects were Indians with no history of orthodontic treatment. An analysis of variance and Duncan's test statistically compared the groups and genders. Results: CIId1 malocclusion showed the narrowest maxillary arch compared with the other types of malocclusions. CIII malocclusion showed largest mandibular arch than other types of malocclusions. Gender dimorphism is more commonly seen in CI normal occlusion than other types of malocclusions. Gender dimorphism is not observed in CIId1 group. Gender comparisons revealed arch width differences between different types of malocclusions more pronounced in males than in females. The maxillary/mandibular intermolar width difference is positive for CI normal occlusion and negative for CIId1, CIId2, and CIII malocclusions, which suggested, the presence of crossbite tendency in CII and CIII malocclusions. Conclusion: The hypothesis is rejected by the findings of this study. PMID:26604575

  3. Cylindrical bubbles and blobs from a Class II Hydrophobin

    NASA Astrophysics Data System (ADS)

    Russo, Paul; Pham, Michael; Blalock, Brad

    2012-02-01

    Cerato ulmin is a class II hydrophobin. In aqueous suspensions, it easily forms cylindrical air bubbles and cylindrical oil blobs. The conditions for formation of these unusual structures will be discussed, along with scattering and microscopic investigations of their remarkable stability. Possible applications in diverse fields including polymer synthesis and oil spill remediation will be considered. Acknowledgment is made to Dr. Wayne C. Richards of the Canadian Forest Service for the gift of Cerato ulmin.

  4. In silico identification of supertypes for class II MHCs.

    PubMed

    Doytchinova, Irini A; Flower, Darren R

    2005-06-01

    The development of epitope-based vaccines, which have wide population coverage, is greatly complicated by MHC polymorphism. The grouping of alleles into supertypes, on the basis of common structural and functional features, addresses this problem directly. In the present study we applied a combined bioinformatics approach, based on analysis of both protein sequence and structure, to identify similarities in the peptide binding sites of 2225 human class II MHC molecules, and thus define supertypes and supertype fingerprints. Two chemometric techniques were used: hierarchical clustering using three-dimensional Comparative Similarity Indices Analysis fields and nonhierarchical k-means clustering using sequence-based z-descriptors. An average consensus of 84% was achieved, i.e., 1872 of 2225 class II molecules were classified in the same supertype by both techniques. Twelve class II supertypes were defined: five DRs, three DQs, and four DPs. The HLA class II supertypes and their fingerprints given in parenthesis are DR1 (Trp(9beta)), DR3 (Glu(9beta), Gln(70beta), and Gln/Arg(74beta)), DR4 (Glu(9beta), Gln/Arg(70beta), and Glu/Ala(74beta)), DR5 (Glu(9beta), Asp(70beta)), and DR9 (Lys/Gln(9beta)); DQ1 (Ala/Gly(86beta)), DQ2 (Glu(86beta), Lys(71beta)), and DQ3 (Glu(86beta), Thr/Asp(71beta)); DPw1 (Asp(84beta) and Lys(69beta)), DPw2 (Gly/Val(84beta) and Glu(69beta)), DPw4 (Gly/Val(84beta) and Lys(69beta)), and DPw6 (Asp(84beta) and Glu(69beta)). Apart from the good agreement between known binding motifs and our classification, several new supertypes, and corresponding thematic binding motifs, were also defined. PMID:15905552

  5. Characterization of recombination in the HLA class II region

    SciTech Connect

    Cullen, M.; Carrington, M.; Noble, J.

    1997-02-01

    Studies of linkage disequilibrium across the HLA class II region have been useful in predicting where recombination is most likely to occur. The strong associations between genes within the 85-kb region from DQB1 to DRB1 are consistent with low frequency of recombination in this segment of DNA. Conversely, a lack of association between alleles of TAP1 and TAP2 ({approximately}15 kb) has been observed, suggesting that recombination occurs here with relatively high frequency. Much of the HLA class II region has now been sequenced, providing the tools to undertake detailed analysis of recombination. Twenty-seven families containing one or two recombinant chromosomes within the 500-kb interval between the DPB1 and DRB1 genes were used to determine patterns of recombination across this region. SSCP analysis and microsatellite typing yielded identification of 127 novel polymorphic markers distributed throughout the class II region, allowing refinement of the site of crossover in 30 class II recombinant chromosomes. The three regions where recombination was observed most frequently are as follows: the 45-kb interval between HLA-DNA and RING3 (11 cases), the 50-kb interval between DQB3 and DQB1 (6 cases), and an 8.8-kb segment of the TAP2 gene (3 cases). Six of the 10 remaining recombinants await further characterization, pending identification of additional informative markers, while four recombinants were localized to other intervals (outliers). Analysis of association between markers flanking HLA-DNA to RING3 (45 kb), as well as TAP1 to TAP2 (15 kb), by use of independent CEPH haplotypes indicated little or no linkage disequilibrium, supporting the familial recombination data. A notable sequence motif located within a region associated with increased rates of recombination consisted of a (TGGA){sub 12} tandem repeat within the TAP2 gene. 74 refs., 3 figs., 2 tabs.

  6. Treatment of a Class II deepbite with microimplant anchorage.

    PubMed

    Park, Hyo-Sang; Kim, Ji-Yeun; Kwon, Tae-Geon

    2011-03-01

    The goal of this report was to illustrate new treatment mechanics for using microimplants for the treatment of a Class II Division 2 deepbite malocclusion. A 29-year-old woman with a deepbite was treated with the aid of microimplant anchorage. Microimplants placed between the maxillary second premolars and first molars were used as anchorage to apply a distal force to the anterior teeth to correct the Class II canine and molar relationships. A distal force was applied to long hooks that were crimped between the lateral incisors and the canines. By applying a backward force to the long hooks, the maxillary anterior teeth experienced palatal root movement with no change in the vertical and anteroposterior positions of the incisal edges. The distal extrusive movement of the maxillary second molars achieved by disengaging the second molars from the archwire during distal force application and an anterior bite-block bonded on the lingual surface of the maxillary central incisors produced the increase in vertical dimension. The distal force to the long extended hooks from the microimplants was possibly good mechanics for obtaining the palatal root movement and correcting the Class II canine and molar relationships. The anterior bite-block and disengagement of the maxillary second molars during distal force application were effective for increasing the vertical dimension.

  7. MHC Class II haplotypes of Colombian Amerindian tribes.

    PubMed

    Yunis, Juan J; Yunis, Edmond J; Yunis, Emilio

    2013-07-01

    We analyzed 1041 individuals belonging to 17 Amerindian tribes of Colombia, Chimila, Bari and Tunebo (Chibcha linguistic family), Embera, Waunana (Choco linguistic family), Puinave and Nukak (Maku-Puinave linguistic families), Cubeo, Guanano, Tucano, Desano and Piratapuyo (Tukano linguistic family), Guahibo and Guayabero (Guayabero Linguistic Family), Curripaco and Piapoco (Arawak linguistic family) and Yucpa (Karib linguistic family). for MHC class II haplotypes (HLA-DRB1, DQA1, DQB1). Approximately 90% of the MHC class II haplotypes found among these tribes are haplotypes frequently encountered in other Amerindian tribes. Nonetheless, striking differences were observed among Chibcha and non-Chibcha speaking tribes. The DRB1*04:04, DRB1*04:11, DRB1*09:01 carrying haplotypes were frequently found among non-Chibcha speaking tribes, while the DRB1*04:07 haplotype showed significant frequencies among Chibcha speaking tribes, and only marginal frequencies among non-Chibcha speaking tribes. Our results suggest that the differences in MHC class II haplotype frequency found among Chibcha and non-Chibcha speaking tribes could be due to genetic differentiation in Mesoamerica of the ancestral Amerindian population into Chibcha and non-Chibcha speaking populations before they entered into South America.

  8. Hantavirus Gc glycoprotein: evidence for a class II fusion protein.

    PubMed

    Tischler, Nicole D; Gonzalez, Angel; Perez-Acle, Tomas; Rosemblatt, Mario; Valenzuela, Pablo D T

    2005-11-01

    Hantavirus cell entry is promoted by its envelope glycoproteins, Gn and Gc, through cell attachment and by fusion between viral and endosomal membranes at low pH. However, the role of Gn and Gc in receptor binding and cell fusion has not yet been defined. In this work, a sequence presenting characteristics similar to those of class II fusion peptides (FPs) of alphavirus E1 and flavivirus E proteins is identified within the hantavirus Gc glycoprotein. A three-dimensional comparative molecular model based on crystallographic data of tick-borne encephalitis virus E protein is proposed for the Andes virus (ANDV) Gc ectodomain, which supports a feasible class II fusion-protein fold. In vitro experimental evidence is provided for the binding activity of the ANDV FP candidate to artificial membranes, as demonstrated by fluorescence anisotropy assays. Taken together, these results support the hypothesis that the Gc glycoprotein of hantaviruses and of other members of the family Bunyaviridae directs the viral fusion activity and that it may be classified as a class II viral fusion protein.

  9. MHC Class II haplotypes of Colombian Amerindian tribes

    PubMed Central

    Yunis, Juan J.; Yunis, Edmond J.; Yunis, Emilio

    2013-01-01

    We analyzed 1041 individuals belonging to 17 Amerindian tribes of Colombia, Chimila, Bari and Tunebo (Chibcha linguistic family), Embera, Waunana (Choco linguistic family), Puinave and Nukak (Maku-Puinave linguistic families), Cubeo, Guanano, Tucano, Desano and Piratapuyo (Tukano linguistic family), Guahibo and Guayabero (Guayabero Linguistic Family), Curripaco and Piapoco (Arawak linguistic family) and Yucpa (Karib linguistic family). for MHC class II haplotypes (HLA-DRB1, DQA1, DQB1). Approximately 90% of the MHC class II haplotypes found among these tribes are haplotypes frequently encountered in other Amerindian tribes. Nonetheless, striking differences were observed among Chibcha and non-Chibcha speaking tribes. The DRB1*04:04, DRB1*04:11, DRB1*09:01 carrying haplotypes were frequently found among non-Chibcha speaking tribes, while the DRB1*04:07 haplotype showed significant frequencies among Chibcha speaking tribes, and only marginal frequencies among non-Chibcha speaking tribes. Our results suggest that the differences in MHC class II haplotype frequency found among Chibcha and non-Chibcha speaking tribes could be due to genetic differentiation in Mesoamerica of the ancestral Amerindian population into Chibcha and non-Chibcha speaking populations before they entered into South America. PMID:23885196

  10. H2-M3 Major Histocompatibility Complex Class Ib-Restricted CD8 T Cells Induced by Salmonella enterica Serovar Typhimurium Infection Recognize Proteins Released by Salmonella Serovar Typhimurium

    PubMed Central

    Ugrinovic, S.; Brooks, C. G.; Robson, J.; Blacklaws, B. A.; Hormaeche, C. E.; Robinson, J. H.

    2005-01-01

    Salmonella enterica serovar Typhimurium causes a typhoid-like disease in mice which has been studied extensively as a model for typhoid fever in humans. CD8 T cells contribute to protection against S. enterica serovar Typhimurium in mice, but little is known about the specificity and major histocompatibility complex (MHC) restriction of the response. We report here that CD8 T-cell lines derived from S. enterica serovar Typhimurium-infected BALB/c mice lysed bone marrow macrophages infected with S. enterica serovar Typhimurium or pulsed with proteins from S. enterica serovar Typhimurium culture supernatants. Cytoxicity was beta-2-microglobulin dependent and largely TAP dependent, although not MHC class Ia restricted, as target cells of several different MHC haplotypes were lysed. The data suggested the participation of class Ib MHC molecules although no evidence for the presence of Qa1-restricted T cells could be found, unlike in previous reports. Instead, the T-cell lines lysed H2-M3-transfected fibroblasts infected with S. enterica serovar Typhimurium SL3261 or treated with Salmonella culture supernatants. Thus, this report increases the number of MHC class Ib antigen-presenting molecules known for Salmonella antigens to three: Qa-1, HLA-E, and now H2-M3. It also expands the range of pathogens that induce H2-M3-restricted CD8 T cells to include an example of gram-negative bacteria. PMID:16299293

  11. Endocytosis of the class I major histocompatibility antigen via a phorbol myristate acetate-inducible pathway is a cell-specific phenomenon and requires the cytoplasmic domain [published erratum appears in J Cell Biol 1989 Sep;109(3):1381

    PubMed Central

    1989-01-01

    Class I major histocompatibility (MHC) antigens are expressed by virtually all mammalian cells, yet their levels of expression and behavior on the cell surface vary in a cell-specific fashion. A panel of lymphoid (both B and T) and nonlymphoid cell lines was used to study the kinetics of internalization of the H-2Ld class I MHC in different cell types. These studies revealed that endocytosis of H-2Ld occurs by both constitutive and PMA-regulated pathways in lymphoid cells, but only by a PMA-refractory pathway in the nonlymphoid cells tested. Transfectant derivatives of the T lymphoma, EL4, which express wild- type or mutant H-2Ld class I MHC antigens, were used to investigate the requirement for the cytoplasmic domain of the class I MHC antigen for its endocytosis in T lymphocytes. These studies showed that modification or deletion of the cytoplasmic domain of H-2Ld abrogates endocytosis via a PMA-regulated pathway. The role of cytoplasmic domain phosphorylation in PMA-inducible endocytosis was examined. The wild- type H-2Ld antigen is phosphorylated in all cell types examined, and this phosphorylation is up-regulated by PMA treatment. In contrast, cytoplasmic domain mutants of H-2Ld fail to be phosphorylated in vivo, in the presence or absence of PMA. The universality of PMA-inducible hyperphosphorylation of the class I MHC antigen among diverse cell types leads us to conclude that phosphorylation of the cytoplasmic domain, while perhaps necessary, is not sufficient for triggering endocytosis via a PMA-inducible pathway. Furthermore, the results with the cytoplasmic domain mutants of H-2Ld suggest that a structural conformation of the class I MHC cytoplasmic domain is required for endocytosis via this route. PMID:2925787

  12. An Important Role for Major Histocompatibility Complex Class I-Restricted T Cells, and a Limited Role for Gamma Interferon, in Protection of Mice against Lethal Herpes Simplex Virus Infection

    PubMed Central

    Holterman, Ai-Xuan; Rogers, Kathleen; Edelmann, Kurt; Koelle, David M.; Corey, Lawrence; Wilson, Christopher B.

    1999-01-01

    Herpes simplex virus (HSV) inhibits major histocompatibility complex (MHC) class I expression in infected cells and does so much more efficiently in human cells than in murine cells. Given this difference, if MHC class I-restricted T cells do not play an important role in protection of mice from HSV, an important role for these cells in humans would be unlikely. However, the contribution of MHC class I-restricted T cells to the control of HSV infection in mice remains unclear. Further, the mechanisms by which these cells may act to control infection, particularly in the nervous system, are not well understood, though a role for gamma interferon (IFN-γ) has been proposed. To address the roles of MHC class I and of IFN-γ, C57BL/6 mice deficient in MHC class I expression (β2 microglobulin knockout [β2KO] mice), in IFN-γ expression (IFN-γKO mice), or in both (IFN-γKO/β2KO mice) were infected with HSV by footpad inoculation. β2KO mice were markedly compromised in their ability to control infection, as indicated by increased lethality and higher concentrations of virus in the feet and spinal ganglia. In contrast, IFN-γ appeared to play at most a limited role in viral clearance. The results suggest that MHC class I-restricted T cells play an important role in protection of mice against neuroinvasive HSV infection and do so largely by mechanisms other than the production of IFN-γ. PMID:9971787

  13. Deletion of naïve T cells recognizing the minor histocompatibility antigen HY with toxin-coupled peptide-MHC class I tetramers inhibits cognate CTL responses and alters immunodominance.

    PubMed

    Hess, Sabrina M; Young, Ellen F; Miller, Keith R; Vincent, Benjamin G; Buntzman, Adam S; Collins, Edward J; Frelinger, Jeffrey A; Hess, Paul R

    2013-12-01

    Alloreactive T-cell responses directed against minor histocompatibility (H) antigens, which arise from diverse genetic disparities between donor and recipient outside the MHC, are an important cause of rejection of MHC-matched grafts. Because clinically significant responses appear to be directed at only a few antigens, the selective deletion of naïve T cells recognizing donor-specific, immunodominant minor H antigens in recipients before transplantation may be a useful tolerogenic strategy. We have previously demonstrated that peptide-MHC class I tetramers coupled to a toxin can efficiently eliminate specific TCR-transgenic T cells in vivo. Here, using the minor histocompatibility antigen HY as a model, we investigated whether toxic tetramers could inhibit the subsequent priming of the two H2-D(b)-restricted, immunodominant T-cell responses by deleting precursor CTL. Immunization of female mice with male bone marrow elicited robust CTL activity against the Uty and Smcy epitopes, with Uty constituting the major response. As hypothesized, toxic tetramer administration prior to immunization increased survival of cognate peptide-pulsed cells in an in vivo CTL assay, and reduced the frequency of corresponding T cells. However, tetramer-mediated decreases in either T-cell population magnified CTL responses against the non-targeted epitope, suggesting that D(b)-Uty(+) and D(b)-Smcy(+) T cells compete for a limited common resource during priming. Toxic tetramers conceivably could be used in combination to dissect manipulate CD8(+) T-cell immunodominance hierarchies, and to prevent the induction of donor-specific, minor H antigen CTL responses in allotransplantation.

  14. Deletion of naïve T cells recognizing the minor histocompatibility antigen HY with toxin-coupled peptide-MHC class I tetramers inhibits cognate CTL responses and alters immunodominance

    PubMed Central

    Hess, Sabrina M.; Young, Ellen F.; Miller, Keith R.; Vincent, Benjamin G.; Buntzman, Adam S.; Collins, Edward J.; Frelinger, Jeffrey A.; Hess, Paul R.

    2013-01-01

    Alloreactive T-cell responses directed against minor histocompatibility (H) antigens, which arise from diverse genetic disparities between donor and recipient outside the MHC, are an important cause of rejection of MHC-matched grafts. Because clinically significant responses appear to be directed at only a few antigens, the selective deletion of naïve T cells recognizing donor-specific, immunodominant minor H antigens in recipients before transplantation may be a useful tolerogenic strategy. We have previously demonstrated that peptide-MHC class I tetramers coupled to a toxin can efficiently eliminate specific TCR-transgenic T cells in vivo. Here, using the minor histocompatibility antigen HY as a model, we investigated whether toxic tetramers could inhibit the subsequent priming of the two H2-Db-restricted, immunodominant T-cell responses by deleting precursor CTL. Immunization of female mice with male bone marrow elicited robust CTL activity against the Uty and Smcy epitopes, with Uty constituting the major response. As hypothesized, toxic tetramer administration prior to immunization increased survival of cognate peptide-pulsed cells in an in vivo CTL assay, and reduced the frequency of corresponding T cells. However, tetramer-mediated decreases in either T-cell population magnified CTL responses against the non-targeted epitope, suggesting that Db-Uty+ and Db-Smcy+ T cells compete for a limited common resource during priming. Toxic tetramers conceivably could be used in combination to dissect or manipulate CD8+ T-cell immunodominance hierarchies, and to prevent the induction of donor-specific, minor H antigen CTL responses in allotransplantation. PMID:24161680

  15. Molecular characterization of MHC class II in the Australian invasive cane toad reveals multiple splice variants.

    PubMed

    Lillie, Mette; Cui, Jian; Shine, Richard; Belov, Katherine

    2016-07-01

    The cane toad has gained notoriety for its invasion across the Australian landscape, with significant impacts on the native Australian fauna. The invasion has accelerated over time, with invading cane toads adapted for highly dispersive traits. This, however, has come at the cost of the immune system, with lower investment in some immune functions. To investigate the cane toad's immunogenetics, we characterized four major histocompatibility complex (MHC) class IIA and three MHC class IIB loci. Preliminary observations suggest very low allelic diversity at all loci. We also observed various splice isoforms. One isoform seen at one class IIA and two class IIB loci was missing exon 2, which is essential to peptide binding and presentation. The other isoform, observed at a class IIA locus, is likely to be a soluble MHC product. These results may suggest a significant role of alternative splicing of MHC loci in the Australian cane toad. PMID:27233954

  16. Spectral Energy Distribution Analysis of Class I and Class II FU Orionis Stars

    NASA Astrophysics Data System (ADS)

    Gramajo, Luciana V.; Rodón, Javier A.; Gómez, Mercedes

    2014-06-01

    FU Orionis stars (FUors) are eruptive pre-main sequence objects thought to represent quasi-periodic or recurring stages of enhanced accretion during the low-mass star-forming process. We characterize the sample of known and candidate FUors in a homogeneous and consistent way, deriving stellar and circumstellar parameters for each object. We emphasize the analysis in those parameters that are supposed to vary during the FUor stage. We modeled the spectral energy distributions of 24 of the 26 currently known FUors, using the radiative transfer code of Whitney et al. We compare our models with those obtained by Robitaille et al. for Taurus class II and I sources in quiescence periods by calculating the cumulative distribution of the different parameters. FUors have more massive disks: we find that ~80% of the disks in FUors are more massive than any Taurus class II and I sources in the sample. Median values for the disk mass accretion rates are ~10-7 M ⊙ yr-1 versus ~10-5 M ⊙ yr-1 for standard young stellar objects (YSOs) and FUors, respectively. While the distributions of envelope mass accretion rates for class I FUors and standard class I objects are similar, FUors, on average, have higher envelope mass accretion rates than standard class II and class I sources. Most FUors (~70%) have envelope mass accretion rates above 10-7 M ⊙ yr-1. In contrast, 60% of the classical YSO sample has an accretion rate below this value. Our results support the current scenario in which changes experimented by the circumstellar disk explain the observed properties of these stars. However, the increase in the disk mass accretion rate is smaller than theoretically predicted, although in good agreement with previous determinations.

  17. Spectral energy distribution analysis of class I and class II FU Orionis stars

    SciTech Connect

    Gramajo, Luciana V.; Gómez, Mercedes; Rodón, Javier A. E-mail: mercedes@oac.uncor.edu

    2014-06-01

    FU Orionis stars (FUors) are eruptive pre-main sequence objects thought to represent quasi-periodic or recurring stages of enhanced accretion during the low-mass star-forming process. We characterize the sample of known and candidate FUors in a homogeneous and consistent way, deriving stellar and circumstellar parameters for each object. We emphasize the analysis in those parameters that are supposed to vary during the FUor stage. We modeled the spectral energy distributions of 24 of the 26 currently known FUors, using the radiative transfer code of Whitney et al. We compare our models with those obtained by Robitaille et al. for Taurus class II and I sources in quiescence periods by calculating the cumulative distribution of the different parameters. FUors have more massive disks: we find that ∼80% of the disks in FUors are more massive than any Taurus class II and I sources in the sample. Median values for the disk mass accretion rates are ∼10{sup –7} M {sub ☉} yr{sup –1} versus ∼10{sup –5} M {sub ☉} yr{sup –1} for standard young stellar objects (YSOs) and FUors, respectively. While the distributions of envelope mass accretion rates for class I FUors and standard class I objects are similar, FUors, on average, have higher envelope mass accretion rates than standard class II and class I sources. Most FUors (∼70%) have envelope mass accretion rates above 10{sup –7} M {sub ☉} yr{sup –1}. In contrast, 60% of the classical YSO sample has an accretion rate below this value. Our results support the current scenario in which changes experimented by the circumstellar disk explain the observed properties of these stars. However, the increase in the disk mass accretion rate is smaller than theoretically predicted, although in good agreement with previous determinations.

  18. MHC class II genes in the European badger (Meles meles): characterization, patterns of variation, and transcription analysis.

    PubMed

    Sin, Yung Wa; Dugdale, Hannah L; Newman, Chris; Macdonald, David W; Burke, Terry

    2012-04-01

    The major histocompatibility complex (MHC) comprises many genes, some of which are polymorphic with numerous alleles. Sequence variation among alleles is most pronounced in exon 2 of the class II genes, which encodes the α1 and β1 domains that form the antigen-binding site (ABS) for the presentation of peptides. The MHC thus plays an important role in pathogen defense. European badgers (Meles meles) are a good species in which to study the MHC, as they harbor a variety of pathogens. We present the first characterization of MHC class II genes, isolated from genomic DNA (gDNA) and complementary DNA (cDNA), in the European badger. Examination of seven individuals revealed four DRB, two DQB, two DQA, and two DRA putatively functional gDNA sequences. All of these sequences, except DRA, exhibited high variability in exon 2; DRB had the highest variability. The ABS codons demonstrated high variability, due potentially to balancing selection, while non-ABS codons had lower variability. Positively selected sites were detected in DRB and DQA. Phylogenetic analysis demonstrated trans-species polymorphism of class II genes. Comparison with cDNA from whole blood revealed that only DRB had a transcription pattern reflecting the alleles that were present in the gDNA, while the other three genes had disparities between gDNA and cDNA. Only one sequence was transcribed, even though two gDNA sequences were present, from each of both DQB and DRA. Our characterization of badger MHC sequences forms a basis for further studies of MHC variability, mate choice, and pathogen resistance in this, and other, species. PMID:22038175

  19. Characterization of expressed class II MHC sequences in the banner-tailed kangaroo rat (Dipodomys spectabilis) reveals multiple DRB loci.

    PubMed

    Busch, Joseph D; Waser, Peter M; DeWoody, J Andrew

    2008-11-01

    Genes of the major histocompatibility complex (MHC) are exceptionally polymorphic due to the combined effects of natural and sexual selection. Most research in wild populations has focused on the second exon of a single class II locus (DRB), but complete gene sequences can provide an illuminating backdrop for studies of intragenic selection, recombination, and organization. To this end, we characterized class II loci in the banner-tailed kangaroo rat (Dipodomys spectabilis). Seven DRB-like sequences (provisionally named MhcDisp-DRB*01 through *07) were isolated from spleen cDNA and most likely comprise > or =5 loci; this multiformity is quite unlike the situation in muroid rodents such as Mus, Rattus, and Peromyscus. In silico translation revealed the presence of important structural residues for glycosylation sites, salt bonds, and CD4+ T-cell recognition. Amino-acid distances varied widely among the seven sequences (2-34%). Nuclear DNA sequences from the Disp-DRB*07 locus (approximately 10 kb) revealed a conventional exon/intron structure as well as a number of microsatellites and short interspersed nuclear elements (B4, Alu, and IDL-Geo subfamilies). Rates of nucleotide substitution at Disp-DRB*07 are similar in both exons and introns (pi = 0.015 and 0.012, respectively), which suggests relaxed selection and may indicate that this locus is an expressed pseudogene. Finally, we performed BLASTn searches against Dipodomys ordii genomic sequences (unassembled reads) and find 90-97% nucleotide similarity between the two kangaroo rat species. Collectively, these data suggest that class II diversity in heteromyid rodents is based on polylocism and departs from the muroid architecture.

  20. Extraordinary MHC class II B diversity in a non-passerine, wild bird: the Eurasian Coot Fulica atra (Aves: Rallidae)

    PubMed Central

    Alcaide, Miguel; Muñoz, Joaquin; Martínez-de la Puente, Josué; Soriguer, Ramón; Figuerola, Jordi

    2014-01-01

    The major histocompatibility complex (MHC) hosts the most polymorphic genes ever described in vertebrates. The MHC triggers the adaptive branch of the immune response, and its extraordinary variability is considered an evolutionary consequence of pathogen pressure. The last few years have witnessed the characterization of the MHC multigene family in a large diversity of bird species, unraveling important differences in its polymorphism, complexity, and evolution. Here, we characterize the first MHC class II B sequences isolated from a Rallidae species, the Eurasian Coot Fulica atra. A next-generation sequencing approach revealed up to 265 alleles that translated into 251 different amino acid sequences (β chain, exon 2) in 902 individuals. Bayesian inference identified up to 19 codons within the presumptive peptide-binding region showing pervasive evidence of positive, diversifying selection. Our analyses also detected a significant excess of high-frequency segregating sites (average Tajima's D = 2.36, P < 0.05), indicative of balancing selection. We found one to six different alleles per individual, consistent with the occurrence of at least three MHC class II B gene duplicates. However, the genotypes comprised of three alleles were by far the most abundant in the population investigated (49.4%), followed by those with two (29.6%) and four (17.5%) alleles. We suggest that these proportions are in agreement with the segregation of MHC haplotypes differing in gene copy number. The most widespread segregating haplotypes, according to our findings, would contain one single gene or two genes. The MHC class II of the Eurasian Coot is a valuable system to investigate the evolutionary implications of gene copy variation and extensive variability, the greatest ever found, to the best of our knowledge, in a wild population of a non-passerine bird. PMID:24683452

  1. Diversification of porcine MHC class II genes: evidence for selective advantage.

    PubMed

    Luetkemeier, Erin S; Malhi, Ripan S; Beever, Jonathan E; Schook, Lawrence B

    2009-02-01

    The major histocompatibility complex (MHC) is an immunological gene-dense region of high diversity in mammalian species. Sus scrofa was domesticated by at least six independent events over Eurasia during the Holocene period. It has been hypothesized that the level and distribution of MHC variation in pig populations reflect genetic selection and environmental influences. In an effort to define the complexity of MHC polymorphisms and the role of selection in the generation of class II gene diversity (DQB, DRB1, and pseudogene PsiDRB3), DNA from globally distributed unrelated domestic pigs of European and Asian origins and a Suidae out-group was analyzed. The number of pseudogene alleles identified (PsiDRB3 33) was greater than those found in the expressed genes (DQB 20 and DRB1 23) but the level of observed heterozygosity (PsiDRB3 0.452, DQB 0.732, and DRB1 0.767) and sequence diversity (PsiDRB3 0.029, DQB 0.062, and DRB1 0.074) were significantly lower in the pseudogene, respectively. The substitution ratios reflected an excess of d (N) (DQB 1.476, DRB1 1.724, and PsiDRB3 0.508) and the persistence of expressed gene alleles suggesting the influence of balancing selection, while the pseudogene was undergoing purifying selection. The lack of a clear MHC phylogeographic tree, coupled with close genetic distances observed between the European and Asian populations (DQB 0.047 and DRB1 0.063) suggested that unlike observations using mtDNA, the MHC diversity lacks phylogeographic structure and appears to be globally uniform. Taken together, these results suggest that, despite regional differences in selective breeding and environments, no skewing of MHC diversity has occurred.

  2. Characterization of bovine MHC class II DRB3 diversity in South American Holstein cattle populations.

    PubMed

    Takeshima, S-N; Giovambattista, G; Okimoto, N; Matsumoto, Y; Rogberg-Muñoz, A; Acosta, T J; Onuma, M; Aida, Y

    2015-12-01

    Holstein cattle dominate the global milk production industry because of their outstanding milk production, however, this breed is susceptible to tropical endemic pathogens and suffers from heat stress and thus fewer Holstein populations are raised in tropical areas. The bovine major histocompatibility complex (BoLA)-DRB3 class II gene is used as a marker for disease and immunological traits, and its polymorphism has been studied extensively in Holstein cattle from temperate and cold regions. We studied the genetic diversity of the BoLA-DRB3 gene in South American Holstein populations to determine whether tropical populations have diverged from those bred in temperate and cold regions by selection and/or crossbreeding with local native breeds. We specifically studied Exon 2 of this gene from 855 South American Holstein individuals by a polymerase chain reaction (PCR) sequence-based typing method. We found a high degree of gene diversity at the allelic (Na > 20 and He > 0.87) and molecular (π > 0.080) levels, but a low degree of population structure (FST = 0.009215). A principal components analysis and tree showed that the Bolivian subtropical population had the largest genetic divergence compared with Holsteins bred in temperate or cold regions, and that this population was closely related to Bolivian Creole cattle. Our results suggest that Holstein genetic divergence can be explained by selection and/or gene introgression from local germplasms. This is the first examination of BoLA-DRB3 in Holsteins adapted to tropical environments, and contributes to an ongoing effort to catalog bovine MHC allele frequencies by breed and location.

  3. Diversification of porcine MHC class II genes: evidence for selective advantage.

    PubMed

    Luetkemeier, Erin S; Malhi, Ripan S; Beever, Jonathan E; Schook, Lawrence B

    2009-02-01

    The major histocompatibility complex (MHC) is an immunological gene-dense region of high diversity in mammalian species. Sus scrofa was domesticated by at least six independent events over Eurasia during the Holocene period. It has been hypothesized that the level and distribution of MHC variation in pig populations reflect genetic selection and environmental influences. In an effort to define the complexity of MHC polymorphisms and the role of selection in the generation of class II gene diversity (DQB, DRB1, and pseudogene PsiDRB3), DNA from globally distributed unrelated domestic pigs of European and Asian origins and a Suidae out-group was analyzed. The number of pseudogene alleles identified (PsiDRB3 33) was greater than those found in the expressed genes (DQB 20 and DRB1 23) but the level of observed heterozygosity (PsiDRB3 0.452, DQB 0.732, and DRB1 0.767) and sequence diversity (PsiDRB3 0.029, DQB 0.062, and DRB1 0.074) were significantly lower in the pseudogene, respectively. The substitution ratios reflected an excess of d (N) (DQB 1.476, DRB1 1.724, and PsiDRB3 0.508) and the persistence of expressed gene alleles suggesting the influence of balancing selection, while the pseudogene was undergoing purifying selection. The lack of a clear MHC phylogeographic tree, coupled with close genetic distances observed between the European and Asian populations (DQB 0.047 and DRB1 0.063) suggested that unlike observations using mtDNA, the MHC diversity lacks phylogeographic structure and appears to be globally uniform. Taken together, these results suggest that, despite regional differences in selective breeding and environments, no skewing of MHC diversity has occurred. PMID:19142631

  4. Epstein-Barr virus LMP2A suppresses MHC class II expression by regulating the B-cell transcription factors E47 and PU.1.

    PubMed

    Lin, Jiun-Han; Lin, Ju-Yin; Chou, Ya-Ching; Chen, Mei-Ru; Yeh, Te-Huei; Lin, Chung-Wu; Lin, Sue-Jane; Tsai, Ching-Hwa

    2015-04-01

    Oncogenic Epstein-Barr virus (EBV) uses various approaches to escape host immune responses and persist in B cells. Such persistent infections may provide the opportunity for this virus to initiate tumor formation. Using EBV-immortalized lymphoblastoid cell lines (LCLs) as a model, we found that the expression of major histocompatibility complex (MHC) class II and CD74 in B cells is repressed after EBV infection. Class II transactivator (CIITA) is the master regulator of MHC class II-related genes. As expected, CIITA was downregulated in LCLs. We showed that downregulation of CIITA is caused by EBV latent membrane protein 2A (LMP2A) and driven by the CIITA-PIII promoter. Furthermore, we demonstrated that LMP2A-mediated E47 and PU.1 reduction resulted in CIITA suppression. Mechanistically, the LMP2A immunoreceptor tyrosine-based activation motif was critical for the repression of E47 and PU.1 promoter activity via Syk, Src, and the phosphatidylinositol 3-kinase/Akt pathway. Elimination of LMP2A in LCLs using a shLMP2A approach showed that the expression levels of E47, PU.1, CIITA, MHC class II, and CD74 are reversed. These data indicated that the LMP2A may reduce MHC class II expression through interference with the E47/PU.1-CIITA pathway. Finally, we demonstrated that MHC class II may be detected in tonsils and EBV-negative Hodgkin disease but not in EBV-associated posttransplant lymphoproliferative disease and Hodgkin disease.

  5. Variations in the Electrostatic Landscape of Class II Human Leukocyte Antigen Molecule Induced by Modifications in the Myelin Basic Protein Peptide: A Theoretical Approach

    PubMed Central

    Agudelo, William A.; Galindo, Johan F.; Ortiz, Marysol; Villaveces, José L.; Daza, Edgar E.; Patarroyo, Manuel E.

    2009-01-01

    The receptor-ligand interactions involved in the formation of the complex between Class II Major Histocompatibility Complex molecules and antigenic peptides, which are essential for establishing an adaptive immunological response, were analyzed in the Class II Human Leukocyte Antigen (HLA) - Myelin Basic Protein (MBP) peptide complex (HLA-DRβ1*1501-MBP) using a multipolar molecular electrostatic potential approach. The Human Leukocyte Antigen - peptide complex system was divided into four pockets together with their respective peptide fragment and the corresponding occupying amino acid was replaced by each of the remaining 19 amino acids. Partial atomic charges were calculated by a quantum chemistry approach at the Hatree Fock/3-21*G level, to study the behavior of monopole, dipole and quadrupole electrostatic multipolar moments. Two types of electrostatic behavior were distinguished in the pockets' amino acids: “anchoring” located in Pocket 1 and 4, and “recognition” located in Pocket 4 and 7. According to variations in the electrostatic landscape, pockets were ordered as: Pocket 1>Pocket 9≫Pocket 4≈Pocket 7 which is in agreement with the binding ability reported for Class II Major Histocompatibility Complex pockets. In the same way, amino acids occupying the polymorphic positions β13R, β26F, β28D, β9W, β74A, β47F and β57D were shown to be key for this Receptor-Ligand interaction. The results show that the multipolar molecular electrostatic potential approach is appropriate for characterizing receptor-ligand interactions in the MHC–antigenic peptide complex, which could have potential implications for synthetic vaccine design. PMID:19132105

  6. Bacterial Superantigens Promote Acute Nasopharyngeal Infection by Streptococcus pyogenes in a Human MHC Class II-Dependent Manner

    PubMed Central

    Kasper, Katherine J.; Zeppa, Joseph J.; Wakabayashi, Adrienne T.; Xu, Stacey X.; Mazzuca, Delfina M.; Welch, Ian; Baroja, Miren L.; Kotb, Malak; Cairns, Ewa; Cleary, P. Patrick; Haeryfar, S. M. Mansour; McCormick, John K.

    2014-01-01

    Establishing the genetic determinants of niche adaptation by microbial pathogens to specific hosts is important for the management and control of infectious disease. Streptococcus pyogenes is a globally prominent human-specific bacterial pathogen that secretes superantigens (SAgs) as ‘trademark’ virulence factors. SAgs function to force the activation of T lymphocytes through direct binding to lateral surfaces of T cell receptors and class II major histocompatibility complex (MHC-II) molecules. S. pyogenes invariably encodes multiple SAgs, often within putative mobile genetic elements, and although SAgs are documented virulence factors for diseases such as scarlet fever and the streptococcal toxic shock syndrome (STSS), how these exotoxins contribute to the fitness and evolution of S. pyogenes is unknown. Here we show that acute infection in the nasopharynx is dependent upon both bacterial SAgs and host MHC-II molecules. S. pyogenes was rapidly cleared from the nasal cavity of wild-type C57BL/6 (B6) mice, whereas infection was enhanced up to ∼10,000-fold in B6 mice that express human MHC-II. This phenotype required the SpeA superantigen, and vaccination with an MHC –II binding mutant toxoid of SpeA dramatically inhibited infection. Our findings indicate that streptococcal SAgs are critical for the establishment of nasopharyngeal infection, thus providing an explanation as to why S. pyogenes produces these potent toxins. This work also highlights that SAg redundancy exists to avoid host anti-SAg humoral immune responses and to potentially overcome host MHC-II polymorphisms. PMID:24875883

  7. Spectrum of MHC Class II Variability in Darwin’s Finches and Their Close Relatives

    PubMed Central

    Sato, Akie; Tichy, Herbert; Grant, Peter R.; Grant, B. Rosemary; Sato, Tetsuji; O’hUigin, Colm

    2011-01-01

    The study describes >400 major histocompatibility complex (MHC) class II B exon 2 and 114 intron 2 sequences of 36 passerine bird species, 13 of which belong to the group of Darwin’s finches (DFs) and the remaining 23 to close or more distant relatives of DFs in Central and South America. The data set is analyzed by a combination of judiciously selected statistical methods. The analysis reveals that reliable information concerning MHC organization, including the assignment of sequences to loci, and evolution, as well as the process of species divergence, can be obtained in the absence of genomic sequence data, if the analysis is taken several steps beyond the standard phylogenetic tree construction approach. The main findings of the present study are these: The MHC class II B region of the passerine birds is as elaborate in its organization, divergence, and genetic diversity as the MHC of the eutherian mammals, specifically the primates. Hence, the reported simplicity of the fowl MHC is an oddity. With the help of appropriate markers, the divergence of the MHC genes can be traced deep in the phylogeny of the bird taxa. Transspecies polymorphism is rampant at many of the bird MHC loci. In this respect, the DFs behave as if they were a single, genetically undifferentiated population. There is thus far no indication of alleles that could be considered species, genus, or even DF group specific. The implication of these findings is that DFs are in the midst of adaptive radiations, in which morphological differentiation into species is running ahead of genetic differentiation in genetic systems such as the MHC or the mitochondrial DNA. The radiations are so young that there has not been enough time to sort out polymorphisms at most of the loci among the morphologically differentiating species. These findings parallel those on Lake Victoria haplochromine fishes. Several of the DF MHC allelic lineages can be traced back to the MHC genes of the species Tiaris obscura

  8. Trans-species polymorphism and selection in the MHC class II DRA genes of domestic sheep.

    PubMed

    Ballingall, Keith T; Rocchi, Mara S; McKeever, Declan J; Wright, Frank

    2010-01-01

    Highly polymorphic genes with central roles in lymphocyte mediated immune surveillance are grouped together in the major histocompatibility complex (MHC) in higher vertebrates. Generally, across vertebrate species the class II MHC DRA gene is highly conserved with only limited allelic variation. Here however, we provide evidence of trans-species polymorphism at the DRA locus in domestic sheep (Ovis aries). We describe variation at the Ovar-DRA locus that is far in excess of anything described in other vertebrate species. The divergent DRA allele (Ovar-DRA*0201) differs from the sheep reference sequences by 20 nucleotides, 12 of which appear non-synonymous. Furthermore, DRA*0201 is paired with an equally divergent DRB1 allele (Ovar-DRB1*0901), which is consistent with an independent evolutionary history for the DR sub-region within this MHC haplotype. No recombination was observed between the divergent DRA and B genes in a range of breeds and typical levels of MHC class II DR protein expression were detected at the surface of leukocyte populations obtained from animals homozygous for the DRA*0201, DRB1*0901 haplotype. Bayesian phylogenetic analysis groups Ovar-DRA*0201 with DRA sequences derived from species within the Oryx and Alcelaphus genera rather than clustering with other ovine and caprine DRA alleles. Tests for Darwinian selection identified 10 positively selected sites on the branch leading to Ovar-DRA*0201, three of which are predicted to be associated with the binding of peptide antigen. As the Ovis, Oryx and Alcelaphus genera have not shared a common ancestor for over 30 million years, the DRA*0201 and DRB1*0901 allelic pair is likely to be of ancient origin and present in the founding population from which all contemporary domestic sheep breeds are derived. The conservation of the integrity of this unusual DR allelic pair suggests some selective advantage which is likely to be associated with the presentation of pathogen antigen to T-cells and the

  9. Trans-species polymorphism and selection in the MHC class II DRA genes of domestic sheep.

    PubMed

    Ballingall, Keith T; Rocchi, Mara S; McKeever, Declan J; Wright, Frank

    2010-06-30

    Highly polymorphic genes with central roles in lymphocyte mediated immune surveillance are grouped together in the major histocompatibility complex (MHC) in higher vertebrates. Generally, across vertebrate species the class II MHC DRA gene is highly conserved with only limited allelic variation. Here however, we provide evidence of trans-species polymorphism at the DRA locus in domestic sheep (Ovis aries). We describe variation at the Ovar-DRA locus that is far in excess of anything described in other vertebrate species. The divergent DRA allele (Ovar-DRA*0201) differs from the sheep reference sequences by 20 nucleotides, 12 of which appear non-synonymous. Furthermore, DRA*0201 is paired with an equally divergent DRB1 allele (Ovar-DRB1*0901), which is consistent with an independent evolutionary history for the DR sub-region within this MHC haplotype. No recombination was observed between the divergent DRA and B genes in a range of breeds and typical levels of MHC class II DR protein expression were detected at the surface of leukocyte populations obtained from animals homozygous for the DRA*0201, DRB1*0901 haplotype. Bayesian phylogenetic analysis groups Ovar-DRA*0201 with DRA sequences derived from species within the Oryx and Alcelaphus genera rather than clustering with other ovine and caprine DRA alleles. Tests for Darwinian selection identified 10 positively selected sites on the branch leading to Ovar-DRA*0201, three of which are predicted to be associated with the binding of peptide antigen. As the Ovis, Oryx and Alcelaphus genera have not shared a common ancestor for over 30 million years, the DRA*0201 and DRB1*0901 allelic pair is likely to be of ancient origin and present in the founding population from which all contemporary domestic sheep breeds are derived. The conservation of the integrity of this unusual DR allelic pair suggests some selective advantage which is likely to be associated with the presentation of pathogen antigen to T-cells and the

  10. 46 CFR 128.210 - Class II vital systems-materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ENGINEERING: EQUIPMENT AND SYSTEMS Materials and Pressure Design § 128.210 Class II vital systems—materials... 46 Shipping 4 2010-10-01 2010-10-01 false Class II vital systems-materials. 128.210 Section 128... chapter, materials used in Class II vital piping-systems may be accepted by the cognizant OCMI or...

  11. 78 FR 24061 - Minimum Technical Standards for Class II Gaming Systems and Equipment

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-24

    ... ensuring the integrity of electronic Class II games and aids. 73 FR 60508, Oct. 10, 2008. The technical... Class II gaming system; and to clarify the term ``alternate standard.'' 77 FR 58473, Sept. 21, 2012. In... control standards (MICS) for Class II gaming. 77 FR 58708, Sept. 21, 2012. Similar to the part...

  12. 40 CFR 147.3400 - Navajo Indian lands-Class II wells.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Navajo Indian lands-Class II wells... Indian Lands § 147.3400 Navajo Indian lands—Class II wells. The UIC program for Class II injection wells... outside those exterior boundaries (collectively referred to as “Navajo Indian lands for which EPA...

  13. 25 CFR 522.5 - Disapproval of a class II ordinance.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Disapproval of a class II ordinance. 522.5 Section 522.5 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.5 Disapproval of a class...

  14. 25 CFR 522.5 - Disapproval of a class II ordinance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Disapproval of a class II ordinance. 522.5 Section 522.5 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.5 Disapproval of a class...

  15. The class II transactivator (CIITA) is regulated by post-translational modification cross-talk between ERK1/2 phosphorylation, mono-ubiquitination and Lys63 ubiquitination.

    PubMed

    Morgan, Julie E; Shanderson, Ronald L; Boyd, Nathaniel H; Cacan, Ercan; Greer, Susanna F

    2015-06-19

    The class II transactivator (CIITA) is known as the master regulator for the major histocompatibility class II (MHC II) molecules. CIITA is dynamically regulated through a series of intricate post-translational modifications (PTMs). CIITA's role is to initiate transcription of MHC II genes, which are responsible for presenting extracellular antigen to CD4(+) T-cells. In the present study, we identified extracellular signal-regulated kinase (ERK)1/2 as the kinase responsible for phosphorylating the regulatory site, Ser(280), which leads to increased levels of mono-ubiquitination and an overall increase in MHC II activity. Further, we identify that CIITA is also modified by Lys(63)-linked ubiquitination. Lys(63) ubiquitinated CIITA is concentrated in the cytoplasm and following activation of ERK1/2, CIITA phosphorylation occurs and Lys=ubiquitinated CIITA translocates to the nucleus. CIITA ubiquitination and phosphorylation perfectly demonstrates how CIITA location and activity is regulated through PTM cross-talk. Identifying CIITA PTMs and understanding how they mediate CIITA regulation is necessary due to the critical role CIITA has in the initiation of the adaptive immune response.

  16. Class I and Class II Histone Deacetylases Are Potential Therapeutic Targets for Treating Pancreatic Cancer

    PubMed Central

    Wang, Guan; He, Jing; Zhao, Jianyun; Yun, Wenting; Xie, Chengzhi; Taub, Jeffrey W.; Azmi, Asfar; Mohammad, Ramzi M.; Dong, Yan; Kong, Wei; Guo, Yingjie; Ge, Yubin

    2012-01-01

    Background Pancreatic cancer is a highly malignant disease with an extremely poor prognosis. Histone deacetylase inhibitors (HDACIs) have shown promising antitumor activities against preclinical models of pancreatic cancer, either alone or in combination with chemotherapeutic agents. In this study, we sought to identify clinically relevant histone deacetylases (HDACs) to guide the selection of HDAC inhibitors (HDACIs) tailored to the treatment of pancreatic cancer. Methodology HDAC expression in seven pancreatic cancer cell lines and normal human pancreatic ductal epithelial cells was determined by Western blotting. Antitumor interactions between class I- and class II-selective HDACIs were determined by MTT assays and standard isobologram/CompuSyn software analyses. The effects of HDACIs on cell death, apoptosis and cell cycle progression, and histone H4, alpha-tubulin, p21, and γH2AX levels were determined by colony formation assays, flow cytometry analysis, and Western blotting, respectively. Results The majority of classes I and II HDACs were detected in the pancreatic cancer cell lines, albeit at variable levels. Treatments with MGCD0103 (a class I-selective HDACI) resulted in dose-dependent growth arrest, cell death/apoptosis, and cell cycle arrest in G2/M phase, accompanied by induction of p21 and DNA double-strand breaks (DSBs). In contrast, MC1568 (a class IIa-selective HDACI) or Tubastatin A (a HDAC6-selective inhibitor) showed minimal effects. When combined simultaneously, MC1568 significantly enhanced MGCD0103-induced growth arrest, cell death/apoptosis, and G2/M cell cycle arrest, while Tubastatin A only synergistically enhanced MGCD0103-induced growth arrest. Although MC1568 or Tubastatin A alone had no obvious effects on DNA DSBs and p21 expression, their combination with MGCD0103 resulted in cooperative induction of p21 in the cells. Conclusion Our results suggest that classes I and II HDACs are potential therapeutic targets for treating pancreatic

  17. Gamma interferon and 5-azacytidine cause transcriptional elevation of class I major histocompatibility complex gene expression in K562 leukemia cells in the absence of differentiation.

    PubMed

    Chen, E; Karr, R W; Frost, J P; Gonwa, T A; Ginder, G D

    1986-05-01

    We studied the effects of gamma interferon (IFN-gamma) on HLA class I gene expression, differentiation, and proliferative capacity of K562 human leukemia cells. In the uninduced state, K562 cells show little or no class I gene expression but actively express the erythroid-specific gamma-globin gene as well as genes associated with cell proliferation, including the transferrin receptor, c-myc, and alpha-actin genes At both the surface protein and mRNA levels, IFN-gamma induces class I and beta 2-microglobulin gene expression, but does not alter the expression of the gamma-globin, transferrin receptor, c-myc, or alpha-actin genes. A 10-fold maximal induction of both class I surface protein and mRNA occurs at 48 h and is reversible upon withdrawal of IFN-gamma from the culture medium. In vitro nuclear run-on transcription assays were performed to directly establish that IFN-gamma exerts an early effect at the level of transcription, with maximal transcription rates occurring within 4 h. The difference between the time course of transcription induction and that of mRNA accumulation suggests that the regulation of class I gene expression in this human leukemic cell line also involves posttranscriptional mechanisms. Measurements of cell proliferation rates and cell cycle distribution, as well as the reversibility of the effects of IFN-gamma, demonstrate that the selective induction of class I genes in these cells occurs in the absence of differentiation.

  18. Dynamics of the Major Histocompatibility Complex Class I Processing and Presentation Pathway in the Course of Malaria Parasite Development in Human Hepatocytes: Implications for Vaccine Development

    PubMed Central

    Ma, Jinxia; Trop, Stefanie; Baer, Samantha; Rakhmanaliev, Elian; Arany, Zita; Dumoulin, Peter; Zhang, Hao; Romano, Julia; Coppens, Isabelle; Levitsky, Victor; Levitskaya, Jelena

    2013-01-01

    Control of parasite replication exerted by MHC class I restricted CD8+ T-cells in the liver is critical for vaccination-induced protection against malaria. While many intracellular pathogens subvert the MHC class I presentation machinery, its functionality in the course of malaria replication in hepatocytes has not been characterized. Using experimental systems based on specific identification, isolation and analysis of human hepatocytes infected with P. berghei ANKA GFP or P. falciparum 3D7 GFP sporozoites we demonstrated that molecular components of the MHC class I pathway exhibit largely unaltered expression in malaria-infected hepatocytes until very late stages of parasite development. Furthermore, infected cells showed no obvious defects in their capacity to upregulate expression of different molecular components of the MHC class I machinery in response to pro-inflammatory lymphokines or trigger direct activation of allo-specific or peptide-specific human CD8+ T-cells. We further demonstrate that ectopic expression of circumsporozoite protein does not alter expression of critical genes of the MHC class I pathway and its response to pro-inflammatory cytokines. In addition, we identified supra-cellular structures, which arose at late stages of parasite replication, possessed the characteristic morphology of merosomes and exhibited nearly complete loss of surface MHC class I expression. These data have multiple implications for our understanding of natural T-cell immunity against malaria and may promote development of novel, efficient anti-malaria vaccines overcoming immune escape of the parasite in the liver. PMID:24086507

  19. Efficient Targeting of Protein Antigen to the Dendritic Cell Receptor DEC-205 in the Steady State Leads to Antigen Presentation on Major Histocompatibility Complex Class I Products and Peripheral CD8+ T Cell Tolerance

    PubMed Central

    Bonifaz, Laura; Bonnyay, David; Mahnke, Karsten; Rivera, Miguel; Nussenzweig, Michel C.; Steinman, Ralph M.

    2002-01-01

    To identify endocytic receptors that allow dendritic cells (DCs) to capture and present antigens on major histocompatibility complex (MHC) class I products in vivo, we evaluated DEC-205, which is abundant on DCs in lymphoid tissues. Ovalbumin (OVA) protein, when chemically coupled to monoclonal αDEC-205 antibody, was presented by CD11c+ lymph node DCs, but not by CD11c− cells, to OVA-specific, CD4+ and CD8+ T cells. Receptor-mediated presentation was at least 400 times more efficient than unconjugated OVA and, for MHC class I, the DCs had to express transporter of antigenic peptides (TAP) transporters. When αDEC-205:OVA was injected subcutaneously, OVA protein was identified over a 4–48 h period in DCs, primarily in the lymph nodes draining the injection site. In vivo, the OVA protein was selectively presented by DCs to TCR transgenic CD8+ cells, again at least 400 times more effectively than soluble OVA and in a TAP-dependent fashion. Targeting of αDEC-205:OVA to DCs in the steady state initially induced 4–7 cycles of T cell division, but the T cells were then deleted and the mice became specifically unresponsive to rechallenge with OVA in complete Freund's adjuvant. In contrast, simultaneous delivery of a DC maturation stimulus via CD40, together with αDEC-205:OVA, induced strong immunity. The CD8+ T cells responding in the presence of agonistic αCD40 antibody produced large amounts of interleukin 2 and interferon γ, acquired cytolytic function in vivo, emigrated in large numbers to the lung, and responded vigorously to OVA rechallenge. Therefore, DEC-205 provides an efficient receptor-based mechanism for DCs to process proteins for MHC class I presentation in vivo, leading to tolerance in the steady state and immunity after DC maturation. PMID:12486105

  20. Tissue-specific and cell surface expression of human major histocompatibility complex class I heavy (HLA-B7) and light (beta 2-microglobulin) chain genes in transgenic mice.

    PubMed Central

    Chamberlain, J W; Nolan, J A; Conrad, P J; Vasavada, H A; Vasavada, H H; Ploegh, H L; Ganguly, S; Janeway, C A; Weissman, S M

    1988-01-01

    We introduced the human genes HLA-B7 and B2M encoding the heavy (HLA-B7) and light [beta 2-microglobulin (beta 2m)] chains of a human major histocompatibility complex class I antigen into separate lines of transgenic mice. The tissue-specific pattern of HLA-B7 RNA expression was similar to that of endogenous class I H-2 genes, although the HLA-B7 gene was about 10-fold underexpressed in liver. Identical patterns of RNA expression were detected whether the HLA-B7 gene contained 12 or 0.66 kilobase(s) (kb) of 5' flanking sequence. The level of expression was copy number dependent and as efficient as that of H-2 genes; gamma interferon enhanced HLA-B7 RNA expression in parallel to that of H-2. In addition to the mechanism(s) responsible for gamma interferon-enhanced expression, there must be at least one other tissue-specific mechanism controlling the constitutive levels of class I RNA. Tissue-specific human beta 2m RNA expression was similar to that of mouse beta 2m, including high-level expression in liver. Cell surface HLA-B7 increased 10- to 17-fold on T cells and on a subset of thymocytes from HLA-B7/B2M doubly transgenic mice compared to HLA-B7 singly transgenic mice. The pattern of expression of HLA-B7 on thymocytes resembled that of H-2K as opposed to H-2D. These results confirm that coexpression of both human chains is required for efficient surface expression and that HLA-B7 may share a regulatory mechanism with H-2K, which distinguishes it from H-2D. Images PMID:2459712

  1. Efficient targeting of protein antigen to the dendritic cell receptor DEC-205 in the steady state leads to antigen presentation on major histocompatibility complex class I products and peripheral CD8+ T cell tolerance.

    PubMed

    Bonifaz, Laura; Bonnyay, David; Mahnke, Karsten; Rivera, Miguel; Nussenzweig, Michel C; Steinman, Ralph M

    2002-12-16

    To identify endocytic receptors that allow dendritic cells (DCs) to capture and present antigens on major histocompatibility complex (MHC) class I products in vivo, we evaluated DEC-205, which is abundant on DCs in lymphoid tissues. Ovalbumin (OVA) protein, when chemically coupled to monoclonal alphaDEC-205 antibody, was presented by CD11c+ lymph node DCs, but not by CD11c- cells, to OVA-specific, CD4+ and CD8+ T cells. Receptor-mediated presentation was at least 400 times more efficient than unconjugated OVA and, for MHC class I, the DCs had to express transporter of antigenic peptides (TAP) transporters. When alphaDEC-205:OVA was injected subcutaneously, OVA protein was identified over a 4-48 h period in DCs, primarily in the lymph nodes draining the injection site. In vivo, the OVA protein was selectively presented by DCs to TCR transgenic CD8+ cells, again at least 400 times more effectively than soluble OVA and in a TAP-dependent fashion. Targeting of alphaDEC-205:OVA to DCs in the steady state initially induced 4-7 cycles of T cell division, but the T cells were then deleted and the mice became specifically unresponsive to rechallenge with OVA in complete Freund's adjuvant. In contrast, simultaneous delivery of a DC maturation stimulus via CD40, together with alphaDEC-205:OVA, induced strong immunity. The CD8+ T cells responding in the presence of agonistic alphaCD40 antibody produced large amounts of interleukin 2 and interferon gamma, acquired cytolytic function in vivo, emigrated in large numbers to the lung, and responded vigorously to OVA rechallenge. Therefore, DEC-205 provides an efficient receptor-based mechanism for DCs to process proteins for MHC class I presentation in vivo, leading to tolerance in the steady state and immunity after DC maturation.

  2. Lysis of pig endothelium by IL-2 activated human natural killer cells is inhibited by swine and human major histocompatibility complex (MHC) class I gene products.

    PubMed

    Itescu, S; Artrip, J H; Kwiatkowski, P A; Wang, S F; Minanov, O P; Morgenthau, A S; Michler, R E

    1997-01-01

    We have previously described a form of xenograft rejection, mediated by natural killer (NK) cells, occurring in pig-to-primate organ transplants beyond the period of antibody-mediated hyperacute rejection. In this study, two distinct NK activation pathways were identified as mechanisms of pig aortic endotheliual cell (PAEC) lysis by human NK cells. Using an antibody-dependent cellular cytotoxicity (ADCC) assay, a progressive increase in human NK lysis of PAEC was observed following incubation with human IgG at increasing serum titer. In the absence of IgG, a second mechanism of PAEC lysis by human NK cells was observed following activation with IL-2. IL-2 activation of human NK cells increased lysis of PAEC by over 3-fold compared with ADCC. These results indicate that IL-2 activation of human NK cells induces significantly higher levels of lytic activity than does conventional ADCC involving IgG and FcRIII. We next investigated the role of MHC class I molecules in the regulation of NK lysis following IL-2 activation. PAEC expression of SLA class I molecules was increased by up to 75% by treatment with human TNFa. Following treatment with TNFa at 1 u/ml, IL-2 activated human NK lysis of PAEC was inhibited at every effector:target (E:T) ratio tested. Maximal effect occurred at an E:T ratio of 10:1, with TNFa inhibiting specific lysis by 59% (p < 0.01). Incubation with an anti-SLA class I Mab, but not IgG isotype control, abrogated the protective effects of TNFa on NK lysis of PAEC, suggesting direct inhibitory effects of SLA class I molecules on human NK function. To investigate whether human MHC class I molecules might have similar effects on human NK lysis of PAEC, further experiments were performed using a soluble peptide derived from the alpha-helical region of HLA-B7. Incubation with the HLA-B7 derived peptide significantly reduced the IL-2 activated NK lytic activity against PAEC in a dose-dependent fashion. Maximal effect occurred at a concentration of 10 mg

  3. HLA class II (DR0401) molecules induce Foxp3+ regulatory T cell suppression of B cells in Plasmodium yoelii strain 17XNL malaria.

    PubMed

    Wijayalath, Wathsala; Danner, Rebecca; Kleschenko, Yuliya; Majji, Sai; Villasante, Eileen Franke; Richie, Thomas L; Brumeanu, Teodor-Doru; David, Chella S; Casares, Sofia

    2014-01-01

    Unlike human malaria parasites that induce persistent infection, some rodent malaria parasites, like Plasmodium yoelii strain 17XNL (Py17XNL), induce a transient (self-curing) malaria infection. Cooperation between CD4 T cells and B cells to produce antibodies is thought to be critical for clearance of Py17XNL parasites from the blood, with major histocompatibility complex (MHC) class II molecules being required for activation of CD4 T cells. In order to better understand the correspondence between murine malaria models and human malaria, and in particular the role of MHC (HLA) class II molecules, we studied the ability of humanized mice expressing human HLA class II molecules to clear Py17XNL infection. We showed that humanized mice expressing HLA-DR4 (DR0401) molecules and lacking mouse MHC class II molecules (EA(0)) have impaired production of specific antibodies to Py17XNL and cannot cure the infection. In contrast, mice expressing HLA-DR4 (DR0402), HLA-DQ6 (DQ0601), HLA-DQ8 (DQ0302), or HLA-DR3 (DR0301) molecules in an EA(0) background were able to elicit specific antibodies and self-cure the infection. In a series of experiments, we determined that the inability of humanized DR0401.EA(0) mice to elicit specific antibodies was due to expansion and activation of regulatory CD4(+) Foxp3(+) T cells (Tregs) that suppressed B cells to secrete antibodies through cell-cell interactions. Treg depletion allowed the DR0401.EA(0) mice to elicit specific antibodies and self-cure the infection. Our results demonstrated a differential role of MHC (HLA) class II molecules in supporting antibody responses to Py17XNL malaria and revealed a new mechanism by which malaria parasites stimulate B cell-suppressogenic Tregs that prevent clearance of infection. PMID:24166949

  4. Cellular components of the immune barrier in the spinal meninges and dorsal root ganglia of the normal rat: immunohistochemical (MHC class II) and electron-microscopic observations.

    PubMed

    Braun, J S; Kaissling, B; Le Hir, M; Zenker, W

    1993-08-01

    This report deals with the distribution, morphology and specific topical relationships of bone-marrow-derived cells (free cells) in the spinal meninges and dorsal root ganglia of the normal rat. The morphology of these cells has been studied by transmission and scanning electron microscopy. Cells expressing the major histocompatibility complex (MHC) class II gene product have been recognized by immunofluorescence. At the level of the transmission electron microscope, free cells are found in all layers of the meninges. Many of them display characteristic ultrastructural features of macrophages, whereas others show a highly vacuolated cytoplasm and are endowed with many processes. These elements lack a conspicuous lysosomal system and might represent dendritic cells. Scanning electron microscopy has revealed that free cells contact the cerebrospinal fluid via abundant cytoplasmic processes that cross the cell layers of the pia mater and of the arachnoid. Cells expressing the MHC class II antigen are also found in all layers of the meninges. They are particularly abundant in the layers immediately adjacent to the subarachnoid space, in the neighbourhood of dural vessels, along the spinal roots and in the dural funnels. In addition to the meninges, strong immunoreactivity for MHC class II antigen is observed in the dorsal root ganglia. The ultrastructural and immunohistochemical findings of this study suggest the existence of a well-developed system of immunological surveillance of the subarachnoid space and of the dorsal root ganglia.

  5. Genetic variation and balancing selection at MHC class II exon 2 in cultured stocks and wild populations of orange-spotted grouper (Epinephelus coioides).

    PubMed

    Meng, Z N; Yang, S; Fan, B; Wang, L; Lin, H R

    2012-11-12

    Major histocompatibility complex (MHC) molecules play vital roles in triggering adaptive immune responses and are considered the most variable molecules in vertebrates. Recently, many studies have focused on the polymorphism and evolution mode of MHC in both model and non-model organisms. Here, we analyzed the MHC class II exon 2-encoding β chain in comparison with the mitochondrial Cytb gene and our previously published microsatellite data set in three cultured stocks and four wild populations of the orange-spotted grouper (Epinephelus coioides) in order to investigate its genetic variation and mechanism of evolution. We detected one to four alleles in one individual, suggesting that at least two loci exist in the orange-spotted grouper, as well as a particularly high level of allelic diversity at the MHC loci. Furthermore, the cultured stocks exhibited reduced allelic diversity compared to the wild counterparts. We found evidence of balancing selection at MHC class II exon 2, and codon sites under positive selection were largely correspondent to the protein-binding region. In addition, MHC class II exon 2 revealed significant differences between population differentiation patterns from the neutral mitochondrial Cytb and microsatellites, which may indicate local adaptation at MHC loci in orange-spotted grouper originating from the South China Sea and Southeast Asia.

  6. Human B lymphoblastoid cells contain distinct patterns of cathepsin activity in endocytic compartments and regulate MHC class II transport in a cathepsin S-independent manner.

    PubMed

    Lautwein, Alfred; Kraus, Marianne; Reich, Michael; Burster, Timo; Brandenburg, J; Overkleeft, Herman S; Schwarz, Gerold; Kammer, Winfried; Weber, Ekkehard; Kalbacher, Hubert; Nordheim, Alfred; Driessen, Christoph

    2004-05-01

    Endocytic proteolysis represents a major functional component of the major histocompatibility complex class II antigen-presentation machinery. Although transport and assembly of class II molecules in the endocytic compartment are well characterized, we lack information about the pattern of endocytic protease activity along this pathway. Here, we used chemical tools that visualize endocytic proteases in an activity-dependent manner in combination with subcellular fractionation to dissect the subcellular distribution of the major cathepsins (Cat) CatS, CatB, CatH, CatD, CatC, and CatZ as well as the asparagine-specific endoprotease (AEP) in human B-lymphoblastoid cells (BLC). Endocytic proteases were distributed in two distinct patterns: CatB and CatZ were most prominent in early and late endosomes but absent from lysosomes, and CatH, CatS, CatD, CatC, and AEP distributed between late endosomes and lysosomes, suggesting that CatB and CatZ might be involved in the initial proteolytic attack on a given antigen. The entire spectrum of protease activity colocalized with human leukocyte antigen-DM and the C-terminal and N-terminal processing of invariant chain (Ii) in late endosomes. CatS was active in all endocytic compartments. Surprisingly and in contrast with results from dendritic cells, inhibition of CatS activity by leucine-homophenylalanine-vinylsulfone-phenol prevented N-terminal processing of Ii but did not alter the subcellular trafficking or surface delivery of class II complexes, as deferred from pulse-chase analysis in combination with subcellular fractionation and biotinylation of cell-surface protein. Thus, BLC contain distinct activity patterns of proteases in endocytic compartments and regulate the intracellular transport and surface-delivery of class II in a CatS-independent manner. PMID:14966190

  7. A growth-related concept for skeletal class II treatment.

    PubMed

    Teuscher, U

    1978-09-01

    The use of a combined activator--high-pull headgear appliance for treatment of Class II, Division 1 malocclusion is presented as a preliminary report. The activator itself is equipped with a palatal bar, lower lip pads, and torque-control auxiliaries for the upper incisors. The face-bow is mounted directly on the activator, and the extraoral force vector is equivalent to that of an anterior high-pull vector. During bite registration the veritcal displacement of the mandible is restricted to a minimum, and the anterior displacement should not exceed 6 mm. On the basis of current knowledge of the growth of the bony facial structures, treatment objectives and a specific approach for skeletal Class II correction are defined. Following these objectives, the therapy aims at correcting the malocclusion without diverting the anterior landmarks of the bony face from their specific lines of growth. This is brought about by the corresponding mechanics of the activator-headgear combination. The corrective effect of this appliance may be assumed to be the result of several different factors. The maxillary dentition is restrained in a posterior cranial direction, and an inhibitory effect on the maxilla counter to its line of development is attained. The mandibular dentition is influenced in an anterior downward direction by means of the bite registration, and the occlusion is unlocked during treatment. Any transfer of distally directed headgear forces from the maxilla to the mandible is prevented. Temporary stimulation of condylar growth, possibly combined with temporary posterior deflection of condylar growth, may also be induced. In this way it is possible to take maximum advantage of condylar growth in the sagittal dimension. Thus, not only is the malocclusion corrected but, at the same time, decisive profile improvement is achieved by anterior development of the mandible. From the experience gained so far with a Class II, Division 1 sample undergoing treatment with the

  8. Evaluation of mandibular length in subjects with Class I and Class II skeletal patterns using the cervical vertebrae maturation.

    PubMed

    Generoso, Rodrigo; Sadoco, Elaine Cristina; Armond, Mônica Costa; Gameiro, Gustavo Hauber

    2010-01-01

    The aim of this study was to compare the mandibular size in boys and girls with Class I and Class II skeletal patterns, taking into consideration the bone maturation stage, as defined by the cervical vertebrae maturation. One hundred and sixty cephalometric radiographs were obtained from subjects (aged between 7 and 12 years) with Class I or Class II skeletal patterns, according to the ANB angle and WITS appraisal. The Class I sample consisted of 80 subjects (40 boys, 40 girls). The Class II sample also consisted of 80 subjects (40 boys, 40 girls). On a cross-sectional basis, mandibular length (Co-Gn) was compared between groups and genders. The between-stages changes were also evaluated, with the cervical vertebrae analysis used for establishing the bone maturation stages at CS2, CS3, CS4 and CS5. The results were statistically analyzed by the Kruskal-Wallis test. The mandibular length differed between skeletal patterns only at the earlier stages of development. In the Class I pattern, the mandibular lengths of boys were greater than those of girls at stages CS2, CS4 and CS5, whereas in the Class II pattern, the mandibular lengths of boys were greater than those of girls at stages CS2, CS3 and CS4. The present results indicate a sexual dimorphism in the mandibular length at almost all stages of bone maturation, in exception of the CS5 stage in Class II.

  9. Structural Basis for the Recognition of Mutant Self by a Tumor-Specific, MHC Class II-Restricted T Cell Receptor

    SciTech Connect

    Deng,L.; Langley, R.; Brown, P.; Xu, G.; Teng, L.; Wang, Q.; Gonzales, M.; Callender, G.; Nishimura, M.; et al.

    2007-01-01

    Structural studies of complexes of T cell receptor (TCR) and peptide-major histocompatibility complex (MHC) have focused on TCRs specific for foreign antigens or native self. An unexplored category of TCRs includes those specific for self determinants bearing alterations resulting from disease, notably cancer. We determined here the structure of a human melanoma-specific TCR (E8) bound to the MHC molecule HLA-DR1 and an epitope from mutant triosephosphate isomerase. The structure had features intermediate between 'anti-foreign' and autoimmune TCR-peptide-MHC class II complexes that may reflect the hybrid nature of altered self. E8 manifested very low affinity for mutant triosephosphate isomerase-HLA-DR1 despite the highly tumor-reactive properties of E8 cells. A second TCR (G4) had even lower affinity but underwent peptide-specific formation of dimers, suggesting this as a mechanism for enhancing low-affinity TCR-peptide-MHC interactions for T cell activation.

  10. A trans-acting major histocompatibility complex-linked gene whose alleles determine gain and loss changes in the antigenic structure of a classical class I molecule

    PubMed Central

    1989-01-01

    The RT1.A locus of the rat MHC encodes the H chain of the single classical class I molecule of this species. One of the alleles of this polymorphic locus, RT1.Aa, is present in several laboratory inbred, congenic, and MHC recombinant rat strains. Studies of the RT1.Aa class I molecule from a number of these strains as a target for CTL show that its antigenicity, both as an alloantigen and a restricting element, is subject to gain and loss alterations by the action of a gene mapping in the MHC to the right of RT1.A. This locus is apparently present in two allelic forms (one possibly a null allele) corresponding to the presence or absence of a dominant transacting modifier, and has been named class I modification, or cim. The antigenic change brought about by cim is scarcely detectable serologically but highly immunogenic for CTL. Biochemical investigations show that cim affects the post- translational modification of RT1.Aa. PMID:2475574

  11. Reproductive failure and the major histocompatibility complex

    SciTech Connect

    Jin, K.; Gill, T.J. III; Ho, H.N.

    1995-06-01

    The association between HLA sharing and recurrent spontaneous abortion (RSA) was tested in 123 couples and the association between HLA sharing, and the outcome of treatment for unexplained infertility by in vitro fertilization (IVF) was tested in 76 couples, by using a new shared-allele test in order to identify more precisely the region of the major histocompatibility complex (MHC) influencing these reproductive defects. The shared-allele test circumvents the problem of rare alleles at HLA loci and at the same time provides a substantial gain in power over the simple {chi}{sup 2} test. Two statistical methods, a corrected homogeneity test and a bootstrap approach, were developed to compare the allele frequencies at each of the HLA-A, HLA-B, HLA-DR, and HLA-DQ loci; they were not statistically different amount the three patient groups and the control group. There was a significant excess of HLA-DR sharing in couples with RSA and a significant excess of HLA-DQ sharing in couples with unexplained infertility who failed treatment by IVF. These findings indicate that genes located in different parts of the class II region of the MHC affect different aspects of reproduction and strongly suggest that the sharing of HLA antigens per se is not the mechanism involved in the reproductive defects. The segment of the MHC that has genes affecting reproduction also has genes associated with different autoimmune diseases, and this juxtaposition may explain the association between reproductive defects and autoimmune diseases. 58 refs., 1 fig., 7 tabs.

  12. Trans-species polymorphism of the Mhc class II DRB-like gene in banded penguins (genus Spheniscus).

    PubMed

    Kikkawa, Eri F; Tsuda, Tomi T; Sumiyama, Daisuke; Naruse, Taeko K; Fukuda, Michio; Kurita, Masanori; Wilson, Rory P; LeMaho, Yvon; Miller, Gary D; Tsuda, Michio; Murata, Koichi; Kulski, Jerzy K; Inoko, Hidetoshi

    2009-05-01

    The Major Histocompatibility Complex (Mhc) class II DRB locus of vertebrates is highly polymorphic and some alleles may be shared between closely related species as a result of balancing selection in association with resistance to parasites. In this study, we developed a new set of PCR primers to amplify, clone, and sequence overlapping portions of the Mhc class II DRB-like gene from the 5'UTR end to intron 3, including exons 1, 2, and 3 and introns 1 and 2 in four species (20 Humboldt, six African, five Magellanic, and three Galapagos penguins) of penguin from the genus Spheniscus (Sphe). Analysis of gene sequence variation by the neighbor-joining method of 21 Sphe sequences and 20 previously published sequences from four other penguin species revealed overlapping clades within the Sphe species, but species-specific clades for the other penguin species. The overlap of the DRB-like gene sequence variants between the four Sphe species suggests that, despite their allopatric distribution, the Sphe species are closely related and that some shared DRB1 alleles may have undergone a trans-species inheritance because of balancing selection and/or recent rapid speciation. The new primers and PCR assays that we have developed for the identification of the DRB1 DNA and protein sequence variations appear to be useful for the characterization of the molecular evolution of the gene in closely related Penguin species and might be helpful for the assessment of the genetic health and the management of the conservation and captivity of these endangered species.

  13. [Therapy of class II, division 1. Orthodontics or surgery?].

    PubMed

    Dereudre, B; Casteigt, J; Lemasson, C; Baysse, F

    1984-01-01

    Concerning five observations of class II division 1, the authors justify therapies they used. Mandibular micrognathia is excluded. Proposed schedules are all based on a precise diagnosis and knowledge of abilities and limits of orthodontics. These limits depend upon orthodontical technics and also, individual factors, particularly if patient is an adult or a child. For a child, orthodontics are preferred and, according with prediction of mandibular growth and child's cooperation, non-extraction therapies are proposed. In adult, correction of deformity ignore such helpful factors as growth and cooperation; nevertheless, it can be successfully treated by orthodontics, using differential extractions, or, if orthodontics are impossible, by orthognathic surgery. Then, surgery will include orthodontical preparation and achievement of dental arches.

  14. Surgical Orthodontic Treatment of Severe Skeletal Class II

    PubMed Central

    Alsulaimani, Fahad F.; Al-Sebaei, Maisa O.; Afify, Ahmed R.

    2013-01-01

    This paper describes an adult Saudi male patient who presented with a severe skeletal class II deformity. The case was managed with a combination of presurgical orthodontic treatment followed by a double jaw orthognathic surgery and then another phase of orthodontic treatment for final occlusal detailing. Extraction of the four first premolars was done during the presurgical orthodontic phase of treatment to decompensate upper and lower incisors and to give room for surgical setback of the maxillary anterior segment. Double jaw surgery was performed: bilateral sagittal split ramus osteotomy for 8 mm mandibular advancement combined with three-piece Le Fort I maxillary osteotomy, 6 mm setback of the anterior segment, 8 mm impaction of the maxilla, and 5 mm advancement genioplasty. Although the anteroposterior discrepancy and the facial convexity were so severe, highly acceptable results were obtained, both esthetically as well as occlusally. PMID:23573428

  15. Crystal structure of swine major histocompatibility complex class I SLA-1 0401 and identification of 2009 pandemic swine-origin influenza A H1N1 virus cytotoxic T lymphocyte epitope peptides.

    PubMed

    Zhang, Nianzhi; Qi, Jianxun; Feng, Sijia; Gao, Feng; Liu, Jun; Pan, Xiaocheng; Chen, Rong; Li, Qirun; Chen, Zhaosan; Li, Xiaoying; Xia, Chun; Gao, George F

    2011-11-01

    The presentation of viral epitopes to cytotoxic T lymphocytes (CTLs) by swine leukocyte antigen class I (SLA I) is crucial for swine immunity. To illustrate the structural basis of swine CTL epitope presentation, the first SLA crystal structures, SLA-1 0401, complexed with peptides derived from either 2009 pandemic H1N1 (pH1N1) swine-origin influenza A virus (S-OIV(NW9); NSDTVGWSW) or Ebola virus (Ebola(AY9); ATAAATEAY) were determined in this study. The overall peptide-SLA-1 0401 structures resemble, as expected, the general conformations of other structure-solved peptide major histocompatibility complexes (pMHC). The major distinction of SLA-1 0401 is that Arg(156) has a "one-ballot veto" function in peptide binding, due to its flexible side chain. S-OIV(NW9) and Ebola(AY9) bind SLA-1 0401 with similar conformations but employ different water molecules to stabilize their binding. The side chain of P7 residues in both peptides is exposed, indicating that the epitopes are "featured" peptides presented by this SLA. Further analyses showed that SLA-1 0401 and human leukocyte antigen (HLA) class I HLA-A 0101 can present the same peptides, but in different conformations, demonstrating cross-species epitope presentation. CTL epitope peptides derived from 2009 pandemic S-OIV were screened and evaluated by the in vitro refolding method. Three peptides were identified as potential cross-species influenza virus (IV) CTL epitopes. The binding motif of SLA-1 0401 was proposed, and thermostabilities of key peptide-SLA-1 0401 complexes were analyzed by circular dichroism spectra. Our results not only provide the structural basis of peptide presentation by SLA I but also identify some IV CTL epitope peptides. These results will benefit both vaccine development and swine organ-based xenotransplantation.

  16. HIV-1 Nef binds PACS-2 to assemble a multikinase cascade that triggers major histocompatibility complex class I (MHC-I) down-regulation: analysis using short interfering RNA and knock-out mice.

    PubMed

    Atkins, Katelyn M; Thomas, Laurel; Youker, Robert T; Harriff, Melanie J; Pissani, Franco; You, Huihong; Thomas, Gary

    2008-04-25

    Human immunodeficiency virus, type 1, negative factor (Nef) initiates down-regulation of cell-surface major histocompatibility complex-I (MHC-I) by assembling an Src family kinase (SFK)-ZAP70/Syk-phosphoinositide 3-kinase (PI3K) cascade through the sequential actions of two sites, Nef EEEE(65) and PXXP(75). The internalized MHC-I molecules are then sequestered in endosomal compartments by a process requiring Nef Met(20). How Nef assembles the multikinase cascade to trigger the MHC-I down-regulation pathway is unknown. Here we report that EEEE(65)-dependent binding to the sorting protein PACS-2 targets Nef to the paranuclear region, enabling PXXP(75) to bind and activate a trans-Golgi network (TGN)-localized SFK. This SFK then phosphorylates ZAP-70 to recruit class I PI3K by interaction with the p85 C-terminal Src homology 2 domain. Using splenocytes and embryonic fibroblasts from PACS-2(-/-) mice, we confirm genetically that Nef requires PACS-2 to localize to the paranuclear region and assemble the multikinase cascade. Moreover, genetic loss of PACS-2 or inhibition of class I PI3K prevents Nef-mediated MHC-I down-regulation, demonstrating that short interfering RNA knockdown of PACS-2 phenocopies the gene knock-out. This PACS-2-dependent targeting pathway is not restricted to Nef, because PACS-2 is also required for trafficking of an endocytosed cation-independent mannose 6-phosphate receptor reporter from early endosomes to the TGN. Together, these results demonstrate PACS-2 is required for Nef action and sorting of itinerant membrane cargo in the TGN/endosomal system.

  17. 40 CFR 82.70 - Nonessential Class II products and exceptions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... in the production of plastic and elastomeric materials, which contain class II substances for solvent... designated as class II in 40 CFR part 82, appendix B to subpart A) are identified as being nonessential and... 21 CFR 2.125(e); (ii) Lubricants, coatings or cleaning fluids for electrical or electronic...

  18. Heligmosomoides polygyrus infection is associated with lower MHC class II gene expression in Apodemus flavicollis: indication for immune suppression?

    PubMed

    Axtner, Jan; Sommer, Simone

    2011-12-01

    Due to their key role in recognizing foreign antigens and triggering the subsequent immune response the genes of the major histocompatibility complex (MHC) provide a potential target for parasites to attack in order to evade detection and expulsion from the host. A diminished MHC gene expression results in less activated T cells and might serve as a gateway for pathogens and parasites. Some parasites are suspected to be immune suppressors and promote co-infections of other parasites even in other parts of the body. In our study we found indications that the gut dwelling nematode Heligmosomoides polygyrus might exert a systemic immunosuppressive effect in yellow-necked mice (Apodemus flavicollis). The amount of hepatic MHC class II DRB gene RNA transcripts in infected mice was negatively associated with infection intensity with H. polygyrus. The hepatic expression of immunosuppressive cytokines, such as transforming growth factor β and interleukin 10 was not associated with H. polygyrus infection. We did not find direct positive associations of H. polygyrus with other helminth species. But the prevalence and infection intensity of the nematodes Syphacia stroma and Trichuris muris were higher in multiple infected individuals. Furthermore, our data indicated antagonistic effects in the helminth community of A. flavicollis as cestode infection correlated negatively with H. polygyrus and helminth species richness. Our study shows that expression analyses of immune relevant genes can also be performed in wildlife, opening new aspects and possibilities for future ecological and evolutionary research. PMID:21983561

  19. Structural Basis for the Presentation of Tumor-Associated MHC Class II-Restricted Phosphopeptides to CD4+ T Cells

    SciTech Connect

    Li, Y.; Depontieu, F; Sidney, J; Salay, T; Engelhard, V; Hunt, D; Sette, A; Topalian, S; Mariuzza, R

    2010-01-01

    Dysregulated protein phosphorylation is a hallmark of malignant transformation. Transformation can generate major histocompatibility complex (MHC)-bound phosphopeptides that are differentially displayed on tumor cells for specific recognition by T cells. To understand how phosphorylation alters the antigenic identity of self-peptides and how MHC class II molecules present phosphopeptides for CD4{sup +} T-cell recognition, we determined the crystal structure of a phosphopeptide derived from melanoma antigen recognized by T cells-1 (pMART-1), selectively expressed by human melanomas, in complex with HLA-DR1. The structure revealed that the phosphate moiety attached to the serine residue at position P5 of pMART-1 is available for direct interactions with T-cell receptor (TCR) and that the peptide N-terminus adopts an unusual conformation orienting it toward TCR. This structure, combined with measurements of peptide affinity for HLA-DR1 and of peptide-MHC recognition by pMART-1-specific T cells, suggests that TCR recognition is focused on the N-terminal portion of pMART-1. This recognition mode appears to be distinct from that of foreign antigen complexes but is remarkably reminiscent of the way autoreactive TCRs engage self- or altered self-peptides, consistent with the tolerogenic nature of tumor-host immune interactions.

  20. MHC class II DRB diversity, selection pattern and population structure in a neotropical bat species, Noctilio albiventris

    PubMed Central

    Schad, J; Dechmann, D K N; Voigt, C C; Sommer, S

    2011-01-01

    Genes of the major histocompatibility complex (MHC) have a crucial role in the immune response of vertebrates, alter the individual odour and are involved in shaping mating preferences. Pathogen-mediated selection, sexual selection and maternal–fetal interactions have been proposed as the main drivers of frequently observed high levels of polymorphism in functionally important parts of the MHC. Bats constitute the second largest mammalian order and have recently emerged as important vectors of infectious diseases. In addition, Chiroptera are interesting study subjects in evolutionary ecology in the context of olfactory communication, mate choice and associated fitness benefits. Thus, it is surprising that they belong to the least studied mammalian taxa in terms of their MHC diversity. In this study, we investigated the variability in the functionally important MHC class II gene DRB, evidence for selection and population structure in the group-living lesser bulldog bat, Noctilio albiventris, in Panama. We found a single expressed, polymorphic Noal-DRB gene. The substitution pattern of the nucleotide sequences of the 18 detected alleles provided evidence for positive selection acting above the evolutionary history of the species in shaping MHC diversity. Roosting colonies were not genetically differentiated but females showed lower levels of heterozygosity than males, which might be a sign that the sexes differ in the selection pressures acting on the MHC. This study provides the prerequisites for further investigations of the role of the individual MHC constitution in parasite resistance, olfactory communication and mate choice in N. albiventris and other bats. PMID:21245894

  1. Constitutive and inducible expression of HLA class II determinants by human osteoblast-like cells in vitro.

    PubMed Central

    Skjødt, H; Hughes, D E; Dobson, P R; Russell, R G

    1990-01-01

    Activated immune cells release cytokines which modulate the activity of bone cells in vitro. Expression of major histocompatibility complex (HLA in humans) class II determinants on bone surface cells may be important in local immune cell activation. In this study, expression of HLA-DR and DQ by cultured human bone cells (HBC) derived from normal trabecular bone surfaces was assessed by fluorescence-activated cell sorter (FACS) analysis and immunoperoxidase techniques using monoclonal antibodies. A subset of HBC (10-30%) expressed DR constitutively while 5-15% displayed DQ during long-term culture. HBC lacked a number of monocyte and lymphocyte markers. In addition, both DR+ and DR- HBC (FACS separated) produced osteocalcin stimulated by 1,25-dihydroxyvitamin D2 (1,25(OH)2D3). This suggests that both phenotypes belong to the osteoblast lineage. The number of DR+ HBC was increased by interferon-gamma (IFN gamma; 40-95% DR+ cells) whereas DQ+ HBC remained unchanged or was slightly increased (5-20% DQ+ cells). Moreover, 1,25(OH)2D3 enhanced IFN gamma-induced DR expression and at high concentration (10(-7) M) augmented DR expression by itself. Other major osteotropic factors, parathyroid hormone, interleukin 1, and calcitonin, did not affect HBC DR expression. The findings suggest that HBC may participate in activation of the immune system and that some osteotropic factors may regulate this function. PMID:2110190

  2. Pseudomonas aeruginosa Cif protein enhances the ubiquitination and proteasomal degradation of the transporter associated with antigen processing (TAP) and reduces major histocompatibility complex (MHC) class I antigen presentation.

    PubMed

    Bomberger, Jennifer M; Ely, Kenneth H; Bangia, Naveen; Ye, Siying; Green, Kathy A; Green, William R; Enelow, Richard I; Stanton, Bruce A

    2014-01-01

    Cif (PA2934), a bacterial virulence factor secreted in outer membrane vesicles by Pseudomonas aeruginosa, increases the ubiquitination and lysosomal degradation of some, but not all, plasma membrane ATP-binding cassette transporters (ABC), including the cystic fibrosis transmembrane conductance regulator and P-glycoprotein. The goal of this study was to determine whether Cif enhances the ubiquitination and degradation of the transporter associated with antigen processing (TAP1 and TAP2), members of the ABC transporter family that play an essential role in antigen presentation and intracellular pathogen clearance. Cif selectively increased the amount of ubiquitinated TAP1 and increased its degradation in the proteasome of human airway epithelial cells. This effect of Cif was mediated by reducing USP10 deubiquitinating activity, resulting in increased polyubiquitination and proteasomal degradation of TAP1. The reduction in TAP1 abundance decreased peptide antigen translocation into the endoplasmic reticulum, an effect that resulted in reduced antigen available to MHC class I molecules for presentation at the plasma membrane of airway epithelial cells and recognition by CD8(+) T cells. Cif is the first bacterial factor identified that inhibits TAP function and MHC class I antigen presentation.

  3. MHC-class-II are expressed in a subpopulation of human neural stem cells in vitro in an IFNγ–independent fashion and during development

    PubMed Central

    Vagaska, B.; New, S. E. P.; Alvarez-Gonzalez, C.; D’Acquisto, F.; Gomez, S. G.; Bulstrode, N. W.; Madrigal, A.; Ferretti, P.

    2016-01-01

    Expression of major histocompatibility antigens class-2 (MHC-II) under non-inflammatory conditions is not usually associated with the nervous system. Comparative analysis of immunogenicity of human embryonic/fetal brain-derived neural stem cells (hNSCs) and human mesenchymal stem cells with neurogenic potential from umbilical cord (UC-MSCs) and paediatric adipose tissue (ADSCs), while highlighting differences in their immunogenicity, led us to discover subsets of neural cells co-expressing the neural marker SOX2 and MHC-II antigen in vivo during human CNS development. MHC-II proteins in hNSCs are functional, and differently regulated upon differentiation along different lineages. Mimicking an inflammatory response using the inflammatory cytokine IFNγ induced MHC-II up-regulation in both astrocytes and hNSCs, but not in UC-MSCs and ADSCs, either undifferentiated or differentiated, though IFNγ receptor expression was comparable. Together, hypoimmunogenicity of both UC-MSCs and ADSCs supports their suitability for allogeneic therapy, while significant immunogenicity of hNSCs and their progeny may at least in part underlie negative effects reported in some patients following embryonic neural cell grafts. Crucially, we show for the first time that MHC-II expression in developing human brains is not restricted to microglia as previously suggested, but is present in discrete subsets of neural progenitors and appears to be regulated independently of inflammatory stimuli. PMID:27080443

  4. Effect of herpes simplex virus types 1 and 2 on surface expression of class I major histocompatibility complex antigens on infected cells.

    PubMed Central

    Jennings, S R; Rice, P L; Kloszewski, E D; Anderson, R W; Thompson, D L; Tevethia, S S

    1985-01-01

    Cytotoxic T lymphocytes (CTL) generated in C57BL/6 (H-2b) mice in response to infection with the serologically distinct herpes simplex virus type 1 (HSV-1) or type 2 (HSV-2) were cross-reactive against target cells infected with either serotype. However, HSV-2-infected cells were shown to be much less susceptible to CTL-mediated lysis, and analysis through the use of HSV-1 X HSV-2 intertypic recombinants mapped the reduced susceptibility to a region contained within 0.82 to 1.00 map units of the HSV-2 genome. The study reported here was undertaken to determine the possible reasons for the reduced susceptibility of HSV-2-infected cells to lysis by CTL. Competition for the specific lysis of labeled HSV-1-infected cells by either HSV-1- or HSV-2-infected, unlabeled inhibitor cells and frequency analysis of the CTL precursor able to recognize HSV-1- and HSV-2-infected cells suggested that the reduced susceptibility of HSV-2-infected cells to lysis could be explained, at least in part, by reduced levels of target cell recognition. A determination of the surface expression of the critical elements involved in target cell recognition by CTL following infection with HSV-1 or HSV-2 revealed that all the major HSV-specific glycoprotein species were expressed. Infection with both HSV-1 and HSV-2 caused a reduction in the expression of the class I H-2 antigens. However, this reduction was much greater following infection with HSV-2. This suggested that one important factor contributing to reduced lysis of HSV-2-infected cells may be the altered or reduced expression of the class I H-2 self-antigens. PMID:2999432

  5. Ubiquitination by March-I prevents MHC class II recycling and promotes MHC class II turnover in antigen-presenting cells.

    PubMed

    Cho, Kyung-Jin; Walseng, Even; Ishido, Satoshi; Roche, Paul A

    2015-08-18

    MHC class II (MHC-II)-dependent antigen presentation by antigen-presenting cells (APCs) is carefully controlled to achieve specificity of immune responses; the regulated assembly and degradation of antigenic peptide-MHC-II complexes (pMHC-II) is one aspect of such control. In this study, we have examined the role of ubiquitination in regulating pMHC-II biosynthesis, endocytosis, recycling, and turnover in APCs. By using APCs obtained from MHC-II ubiquitination mutant mice, we find that whereas ubiquitination does not affect pMHC-II formation in dendritic cells (DCs), it does promote the subsequent degradation of newly synthesized pMHC-II. Acute activation of DCs or B cells terminates expression of the MHC-II E3 ubiquitin ligase March-I and prevents pMHC-II ubiquitination. Most importantly, this change results in very efficient pMHC-II recycling from the surface of DCs and B cells, thereby preventing targeting of internalized pMHC-II to lysosomes for degradation. Biochemical and functional assays confirmed that pMHC-II turnover is suppressed in MHC-II ubiquitin mutant DCs or by acute activation of wild-type DCs. These studies demonstrate that acute APC activation blocks the ubiquitin-dependent turnover of pMHC-II by promoting efficient pMHC-II recycling and preventing lysosomal targeting of internalized pMHC-II, thereby enhancing pMHC-II stability for efficient antigen presentation to CD4 T cells.

  6. Bone marrow transplantation across major histocompatibility barriers in mice: II. T cell requirement for engraftment in total lymphoid irradiation-conditioned recipients

    SciTech Connect

    Vallera, D.A.; Soderling, C.C.B.; Carlson, G.J.; Kersey, J.H.

    1982-03-01

    Studies were undertaken to examine the role of T lymphocytes in engraftment of bone marrow (BM) in animals conditioned with total lymphoid irradiation (TLI) prior to transplantation across major histocompatability barriers.Donor BM (added as a source of lymphohematopoietic stem cells) and spleen cells (added as a source of graft-versus-host disease (GVHD)-causing cells) were pretreated in vitro with monoclonal anti-Thy-1.2 plus complement (C). T cell-depleted grafts were then given to allogeneic mice conditioned with 900 rad of single dose TLI plus cyclophosphamide (CY). These mice did not engraft. Even in the absence of added spleen cells, elimination of the small T cell population from donor BM grafts prevented engraftment compared with animals that received the same conditioning regimen and untreated donor cells. These control animals demonstrated uniform evidence of engraftment about 1 month after transplantation. Similar findings were reported when recipients were conditioned with fractionated 17 x 100-rad TLI. In TLI plus CY-conditioned recipients, it was also observed that increasing the donation of treated bone marrow cells still did not result in significant engraftment. In contrast to TLI conditioning, when Thy-1.2 plus C-treated donor cells were given to recipients conditioned with total body irradiation (TBI), a high percentage of engraftment was demonstrated by an H-2 microcytotoxicity assay. Plausible mechanisms for these findings are discussed. (JMT)

  7. The production and crystallization of the human leukocyte antigen class II molecules HLA-DQ2 and HLA-DQ8 complexed with deamidated gliadin peptides implicated in coeliac disease

    SciTech Connect

    Henderson, Kate N.; Reid, Hugh H.; Borg, Natalie A.; Broughton, Sophie E.; Huyton, Trevor; Anderson, Robert P.; McCluskey, James; Rossjohn, Jamie

    2007-12-01

    The production and crystallization of human leukocyte antigen class II molecules HLA-DQ2 and HLA-DQ8 in complex with deamidated gliadin peptides is reported. Crystals of HLA-DQ2{sup PQPELPYPQ} diffracted to 3.9 Å, while the HLA-DQ8{sup EGSFQPSQE} crystals diffracted to 2.1 Å, allowing structure determination by molecular replacement. The major histocompatibility complex (MHC) class II molecules HLA-DQ2 and HLA-DQ8 are key risk factors in coeliac disease, as they bind deamidated gluten peptides that are subsequently recognized by CD4{sup +} T cells. Here, the production and crystallization of both HLA-DQ2 and HLA-DQ8 in complex with the deamidated gliadin peptides DQ2 α-I (PQPELPYPQ) and DQ8 α-I (EGSFQPSQE), respectively, are reported.

  8. Active site nanospace of aminoacyl tRNA synthetase: difference between the class I and class II synthetases.

    PubMed

    Dutta, Saheb; Choudhury, Kaberi; Banik, Sindrila Dutta; Nandi, Nilashis

    2014-03-01

    The present work is aimed at understanding the origin of the difference in the molecular organization of the active site nanospaces of the class I and class II aminoacyl tRNA synthetases (aaRSs) which are tunnel-like structures. The active site encloses the cognate amino acid (AA) and the adenosine triphosphate (ATP) to carry out aminoacylation reaction. Comparison of the structures of the active site of the class I and class II (aaRSs) shows that the nanodimensional tunnels are curved in opposite directions in the two classes. We investigated the origin of this difference using quantum mechanical computation of electrostatic potential (ESP) of substrates, surrounding residues and ions, using Atoms in Molecule (AIM) Theory and charge population analysis. We show that the difference is principally due to the variation in the spatial charge distribution of ATP in the two classes which correspond to extended and bent conformations of ATP. The present computation shows that the most feasible pathway for nucleophilic attack to alphaP is oppositely directed for class I and class II aaRSs. The available crystal structures show that the cognate AA is indeed located along the channel favorable for nucleophilic attack as predicted by the ESP analysis. It is also shown that the direction of the channel changes its orientation when the orientation of ATP is changed from extended to a bent like structure. We further used the AIM theory to confirm the direction of the approach of AA in each case and the results corroborate the results from the ESP analysis. The opposite curvatures of the active site nanospaces in class I and class II aaRSs are related with the influence of the charge distributions of the extended and bent conformations of ATP, respectively. The results of the computation of electrostatic potential by successive addition of active site residues show that their roles on the reaction are similar in both classes despite the difference in the organization of the

  9. Identification of peptides fromm foot-and-mouth disease virus structural proteins bound by class I swine leucocyte antigen (SLA) alleles, SLA-1*0401 and SLA-2*0401

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The analysis of peptide binding to porcine major histocompatibility complex (MHC) class I molecules has not been extensively performed. Critical to understanding the adaptive immune response of swine to infection is characterization of Swine Leucocyte Antigens (SLA) class I and class II peptide bind...

  10. Nef-induced CD4 and major histocompatibility complex class I (MHC-I) down-regulation are governed by distinct determinants: N-terminal alpha helix and proline repeat of Nef selectively regulate MHC-I trafficking.

    PubMed

    Mangasarian, A; Piguet, V; Wang, J K; Chen, Y L; Trono, D

    1999-03-01

    The Nef protein of primate lentiviruses triggers the accelerated endocytosis of CD4 and of class I major histocompatibility complex (MHC-I), thereby down-modulating the cell surface expression of these receptors. Nef acts as a connector between the CD4 cytoplasmic tail and intracellular sorting pathways both in the Golgi and at the plasma membrane, triggering the de novo formation of CD4-specific clathrin-coated pits (CCP). The downstream partners of Nef in this event are the adapter protein complex (AP) of CCP and possibly a subunit of the vacuolar ATPase. Whether Nef-induced MHC-I down-regulation stems from a similar mechanism is unknown. By comparing human immunodeficiency virus type 1 (HIV-1) Nef mutants for their ability to affect either CD4 or MHC-I expression, both in transient-transfection assays and in the context of HIV-1 infection, it was determined that Nef-induced CD4 and MHC-I down-regulation constitute genetically and functionally separate properties. Mutations affecting only CD4 regulation mapped to residues previously shown to mediate the binding of Nef to this receptor, such as W57 and L58, as well as to an AP-recruiting dileucine motif and to an acidic dipeptide in the C-terminal region of the protein. In contrast, mutation of residues in an alpha-helical region in the proximal portion of Nef and amino acid substitutions in a proline-based SH3 domain-binding motif selectively affected MHC-I down-modulation. Although both the N-terminal alpha-helix and the proline-rich region of Nef have been implicated in recruiting Src family protein kinases, the inhibitor herbimycin A did not block MHC-I down-regulation, suggesting that the latter process is not mediated through an activation of this family of tyrosine kinases. PMID:9971776

  11. Efficient In Vitro Refolding and Characterization of Major Histocompatibility Complex Class I-Related Chain Molecules A (MICA) and Natural Killer Group 2 Member D (NKG2D) Expressed in E. coli.

    PubMed

    Zhao, Xin; Acheampong, Desmond Omane; Wang, Youfu; Tang, Mingying; Xie, Wei; Chen, Zhiguo; Wang, Min; Zhang, Juan

    2015-01-01

    Major Histocompatibility Complex class I-related chain molecules A (MICA) and receptor Natural killer group 2 member D (NKG2D) are important membrane proteins with immunosurveillance properties which could serve as therapeutic targets for immunotherapy. However, expression of MICA and NKG2D in E. coli often leads to the formation of inclusion bodies. Here, we present simple, inexpensive and convenient protocol for the solubilization and refolding of inclusion bodies of MICA and NKG2D expressed in E. coli. The inclusion bodies were firstly dissolved in strong chaotropic reagent (8M urea) and subsequently purified by immobilized-metal affinity column. The denatured MICA/NKG2D was refolded by gradually removing both denaturant (8M urea) and imidazole via dialysis in dialysis buffer of pH 7.4. The appropriate pH of the dialysis buffer was selected based on the theoretical isoelectric points of MICA and NKG2D which were 5.0 and 5.2 respectively. The folded MICA and NKG2D demonstrated the capacity to bind to recombinant NKG2D and MICA respectively by ELISA, Western blot and Surface Plasmon Resonance (SPR) assays. Additionally, the folded MICA and NKG2D demonstrated significant binding to NKG2D-positive Human leukemic cell line U937 and MICA-positive Human pancreatic carcinoma, epithelial-like cell line (PANC-1) respectively, suggesting successful refolding. Successful refolding was further confirmed by Circular Dichroism spectroscopy (CD). We have successfully dissolved, refolded and characterized inclusion bodies of MICA/NKG2D expressed in E. coli using simple, inexpensive and convenient protocol which can be carried out in laboratories under-resourced.

  12. Associations between the major histocompatibility complex class I chain-related gene A transmembrane (MICA-TM) polymorphism and susceptibility to psoriasis and psoriatic arthritis: a meta-analysis.

    PubMed

    Song, Gwan Gyu; Kim, Jae-Hoon; Lee, Young Ho

    2014-01-01

    The aim of this study was to assess whether the major histocompatibility complex class I chain-related gene A transmembrane (MICA-TM) polymorphism is associated with the susceptibility to psoriasis and psoriatic arthritis (PsA). A meta-analysis was conducted to establish the association between the MICA-TM A9 allele and psoriasis and PsA in the general population and each ethnic group. Ten studies (6 psoriasis, 4 PsA) involving 2,002 cases and 1,933 controls were included in this meta-analysis. The Asian controls showed the lowest A9 allele prevalence (16.6%), whereas the European controls had the highest allele prevalence (33.3%). Meta-analysis revealed a significant association between the MICA-TM A9 allele and the entire study population, which included the psoriasis and PsA cases (OR 1.703; 95% CI 1.301-2.229; p = 1.0 × 10(-5)). We further divided the entire study population into the psoriasis and PsA groups. Meta-analysis revealed a significant association between the MICA-TM A9 allele and the entire study population (OR 1.427, 95% CI 1.021-1.994; p = 0.037) and Asians (OR 1.264; 95% CI 1.014-1.576; p = 0.037). A significant association was found between the MICA-TM A9 allele and PsA (OR 2.227; 95% CI 1.462-3.393; p = 1.9 × 10(-5)) and Europeans (OR 2.039; 95% CI 1.285-3.235; p = 0.002). This meta-analysis showed that the MICA-TM A9 allele is associated with psoriasis susceptibility in Asian populations and that the MICA-TM A9 allele is associated with a PsA risk in Europeans.

  13. Molecular characterization of chicken class II transactivator gene.

    PubMed

    Nikbakht Brujeni, Gholamreza; Khosravi, Mohammad

    2015-01-01

    Class II transactivator (CIITA) is an effective transcriptional factor regulating various genes in the immune system. Since the detection of CIITA in 1993, there has been considerable progress toward understanding its role as an activator of MHC II genes in human and mouse; however, there is little knowledge of this gene in other animals such as chicken. Molecular characterization of the chicken CIITA gene transcript was performed to determine its sequence and expression in different tissues. The CIITA cDNA was first generated through reverse transcriptase-polymerase chain reaction (RT-PCR) from Cobb chicken spleen cell RNA, using oligonucleotide primers based on the predicted cDNA sequence. The effect of the immune system stimulation on the CIITA gene expression in kidney, liver, thymus, and spleen were assessed by semi-quantitative RT-PCR analysis. A partial cDNA sequence (1,688 bp) encoding part of the NACHT domain followed by seven of the transactivator and one of the NLS domains were obtained. Comparison of the deduced amino acid sequence with other CIITAs reveals high level of similarities in amino acid composition, secondary structure and phosphorylation sites. Furthermore, in comparison to the Red Jungle Fowl (RJF) sequence, we found 17 single nucleotide polymorphisms in Cobb broiler chicken, ten of which were reported for the first time. Gene expression analysis indicated that CIITA RNA amounts increased in all the examined tissues following stimulation with Brucella antigen. This investigation may indicate that CIITA molecule has an important role in the chicken immune responses as well as human and other animals.

  14. Bone marrow transplantation across major histocompatibility barriers in mice. II. T cell requirement for engraftment in total lymphoid irradiation-conditioned recipients

    SciTech Connect

    Vallera, D.A.; Soderling, C.C.; Carlson, G.J.; Kersey, J.H.

    1982-03-01

    Studies were undertaken to examine the role of T lymphocytes in engraftment of bone marrow (BM) in animals conditioned with total lymphoid irradiation (TLI) prior to transplantation across major histocompatibility barriers. Donor BM (added as a source of lymphohematopoietic stem cells) and spleen cells (added as a source of graft-versus-host disease (GVHD)-causing cells) were pretreated in vitro with monoclonal anti-Thy-1.2 plus complement (C). T cell-depleted grafts were then give to allogeneic mice conditioned with 900 rad of single dose TLI plus cyclophosphamide (CY). These mice did not engraft. Even in the absence of added spleen cells, elimination of the small T cell population from donor BM grafts prevented engraftment compared with animals that received the same conditioning regimen and untreated donor cells. These control animals demonstrated uniform evidence of engraftment about 1 month after transplantation. Similar findings were reported when recipients were conditioned with fractionated 17 x 200-rad TLI. In TLI plus CY-conditional recipients, we have also observed that increasing the donation of treated bone marrow cells still did not result in significant engraftment. Furthermore, graft failure in mice receiving normal dosages of anti-Thy-1.2 plus C-treated donor cells was not a strain-restricted phenomenon. Moreover, removal of bone marrow T cells with monoclonal anti-Lyt-1 plus complement also resulted in graft failure in TLI-conditioned recipients. In contrast to TLI conditioning, when Thy-1.2 plus C-treated donor cells were given to recipients conditioned with total body irradiation (TBI), a high percentage of engraftment was demonstrated by an H-2 microcytotoxicity assay. Plausible mechanisms for there findings are discussed.

  15. Profiling antibodies to class II HLA in transplant patient sera.

    PubMed

    McMurtrey, Curtis; Lowe, Dave; Buchli, Rico; Daga, Sunil; Royer, Derek; Humphrey, Alisha; Cate, Steven; Osborn, Sean; Mojsilovic, Aleksandar; VanGundy, Rodney; Bardet, Wilfried; Duty, Andrew; Mojsilovic, Danijela; Jackson, Kenneth; Stastny, Peter; Briggs, David; Zehnder, Daniel; Higgins, Rob; Hildebrand, William

    2014-03-01

    Immunizing events including pregnancy, transfusions, and transplantation promote strong alloantibody responses to HLA. Such alloantibodies to HLA preclude organ transplantation, foster hyperacute rejection, and contribute to chronic transplant failure. Diagnostic antibody-screening assays detect alloreactive antibodies, yet key attributes including antibody concentration and isotype remain largely unexplored. The goal here was to provide a detailed profile of allogeneic antibodies to class II HLA. Methodologically, alloantibodies were purified from sensitized patient sera using an HLA-DR11 immunoaffinity column and subsequently categorized. Antibodies to DR11 were found to fix complement, exist at a median serum concentration of 2.3μg/mL, consist of all isotypes, and isotypes IgG2, IgM, and IgE were elevated. Because multimeric isotypes can confound diagnostic determinations of antibody concentration, IgM and IgA isotypes were removed and DR11-IgG tested alone. Despite removal of multimeric isotypes, patient-to-patient antibody concentrations did not correlate with MFI values. In conclusion, allogeneic antibody responses to DR11 are comprised of all antibody isotypes at differing proportions, these combined isotypes fix complement at nominal serum concentrations, and enhancements other than the removal of IgM and IgA multimeric isotypes may be required if MFI is to be used as a means of determining anti-HLA serum antibody concentrations in diagnostic clinical assays.

  16. Performance assessment for the class L-II disposal facility

    SciTech Connect

    1997-03-01

    This draft radiological performance assessment (PA) for the proposed Class L-II Disposal Facility (CIIDF) on the Oak Ridge Reservation (ORR) has been prepared to demonstrate compliance with the requirements of the US Department of Energy Order 5820.2A. This PA considers the disposal of low-level radioactive wastes (LLW) over the operating life of the facility and the long-term performance of the facility in providing protection to public health and the environment. The performance objectives contained in the order require that the facility be managed to accomplish the following: (1) Protect public health and safety in accordance with standards specified in environmental health orders and other DOE orders. (2) Ensure that external exposure to the waste and concentrations of radioactive material that may be released into surface water, groundwater, soil, plants, and animals results in an effective dose equivalent (EDE) that does not exceed 25 mrem/year to a member of the public. Releases to the atmosphere shall meet the requirements of 40 CFR Pt. 61. Reasonable effort should be made to maintain releases of radioactivity in effluents to the general environment as low as reasonably achievable. (1) Ensure that the committed EDEs received by individual who inadvertently may intrude into the facility after the loss of active institutional control (100 years) will not exceed 100 mrem/year for continuous exposure of 500 mrem for a single acute exposure. (4) Protect groundwater resources, consistent with federal, state, and local requirements.

  17. Pseudomycoicidin, a Class II Lantibiotic from Bacillus pseudomycoides

    PubMed Central

    Basi-Chipalu, Shradha; Dischinger, Jasmin; Josten, Michaele; Szekat, Christiane; Zweynert, Annegret; Sahl, Hans-Georg

    2015-01-01

    Lantibiotics are ribosomally synthesized antimicrobial peptides with substantial posttranslational modifications. They are characterized by the unique amino acids lanthionine and methyllanthionine, which are introduced by dehydration of Ser/Thr residues and linkage of the resulting dehydrated amino acids with Cys residues. BLAST searches using the mersacidin biosynthetic enzyme (MrsM) in the NCBI database revealed a new class II lantibiotic gene cluster in Bacillus pseudomycoides DSM 12442. Production of an antimicrobial substance with activity against Gram-positive bacteria was detectable in a cell wash extract of this strain. The substance was partially purified, and mass spectrometric analysis predicted a peptide of 2,786 Da in the active fraction. In order to characterize the putative lantibiotic further, heterologous expression of the predicted biosynthetic genes was performed in Escherichia coli. Coexpression of the prepeptide (PseA) along with the corresponding modification enzyme (PseM) resulted in the production of a modified peptide with the corresponding mass, carrying four out of eight possible dehydrations and supporting the presence of four thioether and one disulfide bridge. After the proteolytic removal of the leader, the core peptide exhibited antimicrobial activity. In conclusion, pseudomycoicidin is a novel lantibiotic with antimicrobial activity that was heterologously produced in E. coli. PMID:25769830

  18. Anteroposterior condylar position: A comparative study between subjects with normal occlusion and patients with Class I, Class II Division 1, and Class III malocclusions

    PubMed Central

    Fraga, Marcelo Reis; Rodrigues, Andréia Fialho; Ribeiro, Luiz Claudio; da Silva Campos, Marcio José; Vitral, Robert Willer Farinazzo

    2013-01-01

    Background The present study aimed to determine and compare the anteroposterior position of the condyle in the mandibular fossa between groups of asymptomatic subjects with normal occlusion and asymptomatic subjects with Class I, Class II Division 1, and Class III malocclusions. Material/Methods Thirty persons with normal occlusion, 30 with Class I malocclusion, 30 with Class II Division 1, and 30 with Class III had computed tomography scans of their temporomandibular joints. The anterior joint space/posterior joint space (AJS/PJS) ratio was determined for the right and left joints. The paired t test was used to analyze the AJS/PJS ratio between both sides for each group. The ANOVA test was applied to verify the differences between the groups for the measurements of the right and left sides. In case the ANOVA test confirmed significance, the Dunnett’s t test was performed to compare the groups of malocclusion with that of normal occlusion. Results The paired t test between the AJS/PJS relationships in the right and left sides showed the following p values: Class I (0.168), Class II Division 1 (0.662), Class III (0.991), and normal occlusion (0.390). The ANOVA test showed a p value of 0.445 for the comparisons of the right side and 0.040 for the left side. The Dunnett’s t test demonstrated a statistically significant difference between the Class II group and the normal occlusion group (p value of 0.026) in the joints of the left side. Conclusions Bilateral symmetry and lack of condyle centralization were common characteristics among all groups. The greatest condylar decentralization was observed in the Class II group, whereas the least condylar decentralization was found in the normal occlusion group. PMID:24165809

  19. 40 CFR Figure C-2 to Subpart C of... - Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Illustration of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate Equivalent Methods C Figure C-2 to Subpart C of Part 53... of the Slope and Intercept Limits for Class II and Class III PM2.5 Candidate Equivalent...

  20. 40 CFR 144.22 - Existing Class II enhanced recovery and hydrocarbon storage wells.

    Code of Fed