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Sample records for cell antigen recognition

  1. ɣδ T cell receptor ligands and modes of antigen recognition

    PubMed Central

    Champagne, Eric

    2011-01-01

    T lymphocytes expressing the γδ-type of T cell receptors for antigens contribute to all aspects of immune responses, including defenses against viruses, bacteria, parasites and tumors, allergy and autoimmunity. Multiple subsets have been individualized in humans as well as in mice and they appear to recognize in a TCR-dependent manner antigens as diverse as small non-peptidic molecules, soluble or membrane-anchored polypeptides and molecules related to MHC antigens on cell surfaces, implying diverse modes of antigen recognition. We review here the γδ TCR ligands which have been identified along the years and their characteristics, with emphasis on a few systems which have been extensively studied such as human γδ T cells responding to phosphoantigens or murine γδ T cells activated by allogeneic MHC antigens. We discuss a speculative model of antigen recognition involving simultaneous TCR recognition of MHC-like and non-MHC ligands which could fit with most available data and shares many similarities with the classical model of MHC-restricted antigen recognition for peptides or lipids by T cells subsets with αβ-type TCRs. PMID:21298486

  2. Atypical natural killer T-cell receptor recognition of CD1d–lipid antigens

    PubMed Central

    Le Nours, Jérôme; Praveena, T.; Pellicci, Daniel G.; Gherardin, Nicholas A.; Ross, Fiona J.; Lim, Ricky T.; Besra, Gurdyal S.; Keshipeddy, Santosh; Richardson, Stewart K.; Howell, Amy R.; Gras, Stephanie; Godfrey, Dale I.; Rossjohn, Jamie; Uldrich, Adam P.

    2016-01-01

    Crucial to Natural Killer T (NKT) cell function is the interaction between their T-cell receptor (TCR) and CD1d-antigen complex. However, the diversity of the NKT cell repertoire and the ensuing interactions with CD1d-antigen remain unclear. We describe an atypical population of CD1d–α-galactosylceramide (α-GalCer)-reactive human NKT cells that differ markedly from the prototypical TRAV10-TRAJ18-TRBV25-1+ type I NKT cell repertoire. These cells express a range of TCR α- and β-chains that show differential recognition of glycolipid antigens. Two atypical NKT TCRs (TRAV21-TRAJ8-TRBV7–8 and TRAV12-3-TRAJ27-TRBV6-5) bind orthogonally over the A′-pocket of CD1d, adopting distinct docking modes that contrast with the docking mode of all type I NKT TCR-CD1d-antigen complexes. Moreover, the interactions with α-GalCer differ between the type I and these atypical NKT TCRs. Accordingly, diverse NKT TCR repertoire usage manifests in varied docking strategies and specificities towards CD1d–α-GalCer and related antigens, thus providing far greater scope for diverse glycolipid antigen recognition. PMID:26875526

  3. A structural basis for antigen recognition by the T cell-like lymphocytes of sea lamprey

    SciTech Connect

    Deng, Lu; Velikovsky, C. Alejandro; Xu, Gang; Iyer, Lakshminarayan M.; Tasumi, Satoshi; Kerzic, Melissa C.; Flajnik, Martin F.; Aravind, L.; Pancer, Zeev; Mariuzza, Roy A.

    2010-10-28

    Adaptive immunity in jawless vertebrates is mediated by leucine-rich repeat proteins called 'variable lymphocyte receptors' (VLRs). Two types of VLR (A and B) are expressed by mutually exclusive lymphocyte populations in lamprey. VLRB lymphocytes resemble the B cells of jawed vertebrates; VLRA lymphocytes are similar to T cells. We determined the structure of a high-affinity VLRA isolated from lamprey immunized with hen egg white lysozyme (HEL) in unbound and antigen-bound forms. The VLRA-HEL complex demonstrates that certain VLRAs, like {gamma}{delta} T-cell receptors (TCRs) but unlike {alpha}{beta} TCRs, can recognize antigens directly, without a requirement for processing or antigen-presenting molecules. Thus, these VLRAs feature the nanomolar affinities of antibodies, the direct recognition of unprocessed antigens of both antibodies and {gamma}{delta} TCRs, and the exclusive expression on the lymphocyte surface that is unique to {alpha}{beta} and {gamma}{delta} TCRs.

  4. Intravacuolar Membranes Regulate CD8 T Cell Recognition of Membrane-Bound Toxoplasma gondii Protective Antigen.

    PubMed

    Lopez, Jodie; Bittame, Amina; Massera, Céline; Vasseur, Virginie; Effantin, Grégory; Valat, Anne; Buaillon, Célia; Allart, Sophie; Fox, Barbara A; Rommereim, Leah M; Bzik, David J; Schoehn, Guy; Weissenhorn, Winfried; Dubremetz, Jean-François; Gagnon, Jean; Mercier, Corinne; Cesbron-Delauw, Marie-France; Blanchard, Nicolas

    2015-12-15

    Apicomplexa parasites such as Toxoplasma gondii target effectors to and across the boundary of their parasitophorous vacuole (PV), resulting in host cell subversion and potential presentation by MHC class I molecules for CD8 T cell recognition. The host-parasite interface comprises the PV limiting membrane and a highly curved, membranous intravacuolar network (IVN) of uncertain function. Here, using a cell-free minimal system, we dissect how membrane tubules are shaped by the parasite effectors GRA2 and GRA6. We show that membrane association regulates access of the GRA6 protective antigen to the MHC I pathway in infected cells. Although insertion of GRA6 in the PV membrane is key for immunogenicity, association of GRA6 with the IVN limits presentation and curtails GRA6-specific CD8 responses in mice. Thus, membrane deformations of the PV regulate access of antigens to the MHC class I pathway, and the IVN may play a role in immune modulation.

  5. Low-avidity recognition by CD4+ T cells directed to self-antigens.

    PubMed

    Gebe, John A; Falk, Ben A; Rock, Kellee A; Kochik, Sharon A; Heninger, Anne K; Reijonen, Helena; Kwok, William W; Nepom, Gerald T

    2003-05-01

    Self-reactive T cells populate the peripheral immune system, and likely form the reservoir from which autoreactive cells are derived. We analyzed a panel of self and non-self peptides presented by HLA-DR4, a class II molecule associated with autoimmunity, by immunization of mice transgenic for HLA-DR4. Significant structural avidity for T cell recognition, as measured by MHC class II tetramer binding to CD4(+) T cells was only observed in mice immunized with the non-self antigens. T cell hybridomas were generated from mice immunized with the naturally processed self-peptide hGAD65 (552-572) and also from mice immunized with an influenza-derived non-self epitope (HA 306-318). T cells specific for the self peptide failed to bind tetramers and exhibited low functional avidity as measured by the peptide concentration required to reach half-maximum proliferation values. In contrast, T cells specific for the non-self HA (306-318) peptide exhibited high structural and functional avidity profiles. As recently described in studies of murine CD8(+) T cell function, the predominance of low avidity recognition of self-peptide epitopes may be a characteristic feature of CD4(+) T cells responding to autoantigens.

  6. Innate and humoral recognition of the products of cell death: differential antigenicity and immunogenicity in lupus.

    PubMed

    Arora, P; Malik, M; Sachdeva, R; Saxena, L; Das, J; Ramachandran, V G; Pal, R

    2017-03-01

    While apoptotic debris is believed to constitute the original antigenic insult in lupus (which is characterized by a time-dependent diversification of autoreactivity), whether such debris and autoantibodies specifically recognizing its constituents mediate differential effects on innate and humoral responses in lupus-prone mice is currently unknown. Apoptotic blebs (as opposed to cellular lysate) enhanced preferentially the maturation of dendritic cells (DCs) from bone marrow precursors drawn from lupus-prone mice. Murine, somatically mutated, apoptotic cell-reactive immunoglobulin (Ig)G monoclonal antibodies demonstrated enhanced recognition of DCs and also displayed a prominent lupus strain-specific bias in mediating DC maturation. Further, immunization of such antibodies specifically in lupus-prone mice resulted in widespread humoral autoreactivity; hypergammaglobulinaemia (a hallmark of systemic autoimmunity) was observed, accompanied by enhanced antibody titres to cellular moieties. Induced antibodies recognized antigens distinct from those recognized by the antibodies employed for immunization; in particular, nephritis-associated anti-double stranded (ds) DNA antibodies and neonatal lupus-associated anti-Ro60 antibodies were elicited by a non-dsDNA, non-Ro60 reactive antibody, and Sm was a favoured target. Further, only in lupus-prone mice did such immunization enhance the kinetics of humoral anti-self responses, resulting in the advanced onset of glomerulosclerosis. These studies reveal that preferential innate and humoral recognition of the products of cell death in a lupus milieu influence the indices associated with autoimmune pathology.

  7. Immune recognition of protein antigens

    SciTech Connect

    Laver, W.G.; Air, G.M.

    1985-01-01

    This book contains 33 papers. Some of the titles are: Antigenic Structure of Influenze Virus Hemagglutinin; Germ-line and Somatic Diversity in the Antibody Response to the Influenza Virus A/PR/8/34 Hemagglutinin; Recognition of Cloned Influenza A Virus Gene Products by Cytotoxic T Lymphocytes; Antigenic Structure of the Influenza Virus N2 Neuraminidase; and The Molecular and Genetic Basis of Antigenic Variation in Gonococcal Pillin.

  8. T-cell recognition of a cross-reactive antigen(s) in erythrocyte stages of Plasmodium falciparum and Plasmodium yoelii: inhibition of parasitemia by this antigen(s).

    PubMed Central

    Lucas, B; Engels, A; Camus, D; Haque, A

    1993-01-01

    In the current study, we investigated the presence of a cross-reactive antigen(s) in the erythrocyte stage from Plasmodium yoelii (265 BY strain) and Plasmodium falciparum through recognition by T cells primed in vivo with antigens from each of these parasites. BALB/c mice are naturally resistant to P. falciparum but are susceptible to P. yoelii infection. Mice that had recovered from P. yoelii primary infection became resistant to a second infection. A higher in vitro proliferative response to a soluble blood stage preparation of P. falciparum was observed in splenic cells from immune animals than in those from mice with a patent P. yoelii infection. The antigen-induced proliferative response was enhanced when animals were exposed to a secondary infection. Animals exposed to a challenge infection were treated with anti-CD4 or anti-CD8 monoclonal antibodies to deplete the corresponding subset of T cells. There was a marked diminution in P. falciparum antigen-induced proliferative response in the total splenic cell populations from CD8-depleted but not from CD4-depleted mice. In CD8-depleted and nondepleted animals, the antigen-induced proliferation in the total cell populations was markedly lower than in the T-cell-rich populations, indicating inhibitory activities of B cells and/or macrophages. There was no such difference in the stimulation between total and T-enriched cell populations from CD4-depleted animals. Flow cytometry analysis demonstrated the presence of an almost equal percentage of CD8+ (59.6%) and CD4+ (64%) T cells in the spleen preparations following in vivo depletion of CD4- and CD8-bearing T cells, respectively. When cultured with P. yoelii blood stage antigen, splenocytes from animals immunized with P. falciparum antigen displayed a significant proliferative response which was markedly diminished by treatment with anti-Thy-1.2 antibody plus complement. Animals immunized with P. falciparum antigen and then challenged with P. yoelii blood stage

  9. Recombinant Salmonella typhimurium strains that invade nonphagocytic cells are resistant to recognition by antigen-specific cytotoxic T lymphocytes.

    PubMed Central

    Gao, X M; Tite, J P; Lipscombe, M; Rowland-Jones, S; Ferguson, D J; McMichael, A J

    1992-01-01

    To address the question of whether Salmonella-infected nonphagocytic cells could serve as target cells for recognition by antigen-specific, major histocompatibility complex class I-restricted cytotoxic T lymphocytes (CTL), four recombinant Salmonella typhimurium constructs that expressed full-length, or fragments of, influenza A virus nucleoprotein (NP) were made. The bacteria were shown to infect Chinese hamster ovary (CHO) cells. Appropriate major histocompatibility complex restriction molecules, HLA-B27 and H-2 Db, were transfected into CHO cells, which were then infected with recombinant S. typhimurium and used as targets for NP-specific CTL. The cells in which NP was expressed by intracellularly replicating bacteria were not lysed by NP-specific CTL, although they were killed when appropriate influenza A virus or peptides were used. Thus, S.typhimurium bacteria within nonphagocytic cells were resistant to CTL recognition. In contrast to these results, mice infected with recombinant S.typhimurium that expressed fragments of NP in the periplasm were primed for NP-specific CTL responses. The results indicate that CTL responses specific to Salmonella antigens can be generated, but the bacteria may be safe from the CTL attack once they have entered the nonphagocytic cells. Images PMID:1500187

  10. The Tumor Antigen NY-ESO-1 Mediates Direct Recognition of Melanoma Cells by CD4+ T Cells after Intercellular Antigen Transfer.

    PubMed

    Fonteneau, Jean Francois; Brilot, Fabienne; Münz, Christian; Gannagé, Monique

    2016-01-01

    NY-ESO-1-specific CD4(+) T cells are of interest for immune therapy against tumors, because it has been shown that their transfer into a patient with melanoma resulted in tumor regression. Therefore, we investigated how NY-ESO-1 is processed onto MHC class II molecules for direct CD4(+) T cell recognition of melanoma cells. We could rule out proteasome and autophagy-dependent endogenous Ag processing for MHC class II presentation. In contrast, intercellular Ag transfer, followed by classical MHC class II Ag processing via endocytosis, sensitized neighboring melanoma cells for CD4(+) T cell recognition. However, macroautophagy targeting of NY-ESO-1 enhanced MHC class II presentation. Therefore, both elevated NY-ESO-1 release and macroautophagy targeting could improve melanoma cell recognition by CD4(+) T cells and should be explored during immunotherapy of melanoma.

  11. Disruption of HLA class II antigen presentation in Burkitt lymphoma: implication of a 47,000 MW acid labile protein in CD4+ T-cell recognition.

    PubMed

    God, Jason M; Zhao, Dan; Cameron, Christine A; Amria, Shereen; Bethard, Jennifer R; Haque, Azizul

    2014-07-01

    While Burkitt lymphoma (BL) has a well-known defect in HLA class I-mediated antigen presentation, the exact role of BL-associated HLA class II in generating a poor CD4(+) T-cell response remains unresolved. Here, we found that BL cells are deficient in their ability to optimally stimulate CD4(+) T cells via the HLA class II pathway. This defect in CD4(+) T-cell recognition was not associated with low levels of co-stimulatory molecules on BL cells, as addition of external co-stimulation failed to elicit CD4(+) T-cell activation by BL. Further, the defect was not caused by faulty antigen/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Interestingly, functional class II-peptide complexes were formed at acidic pH 5·5, which restored immune recognition. Acidic buffer (pH 5·5) eluate from BL cells contained molecules that impaired class II-mediated antigen presentation and CD4(+) T-cell recognition. Biochemical analysis showed that these molecules were greater than 30,000 molecular weight in size, and proteinaceous in nature. In addition, BL was found to have decreased expression of a 47,000 molecular weight enolase-like molecule that enhances class II-mediated antigen presentation in B cells, macrophages and dendritic cells, but not in BL cells. These findings demonstrate that BL likely has multiple defects in HLA class II-mediated antigen presentation and immune recognition, which may be exploited for future immunotherapies.

  12. Molecular analysis of antigen recognition by insulin-specific T-cell hybridomas from B6 wild-type and bm12 mutant mice.

    PubMed Central

    Sherman, D H; Hochman, P S; Dick, R; Tizard, R; Ramachandran, K L; Flavell, R A; Huber, B T

    1987-01-01

    Molecular analysis of the heterodimeric T-cell antigen receptor of insulin-specific class II-restricted T-cell hybridomas (THys) derived from C57BL/6 (B6) wild-type and B6.C-H-2bm12 (bm12) mutant mice revealed that such T cells use a diverse V gene repertoire. Analysis of three THys that use related V genes, however, showed a number of novel features. Two THys that share major histocompatibility complex restriction use V alpha genes that are 98.6% homologous. Two THys sharing the same antigen fine specificity use a particular germ line V beta D beta J beta combination. A 21-base-pair deletion in the 5' segment of the J beta gene occurs in one THy, suggesting a novel mechanism for generating diversity in T-cell antigen receptor beta genes. The first amino acid encoded by N sequences at the V-D junction is conserved in a pair of T cells which recognize identical antigenic epitopes. The implications of these findings for the structural mechanisms underlying major histocompatibility complex-restricted antigen-specific T-cell recognition are discussed. Images PMID:2439899

  13. γ-Radiation Promotes Immunological Recognition of Cancer Cells through Increased Expression of Cancer-Testis Antigens In Vitro and In Vivo

    PubMed Central

    Bode, Beata; Wenger, Roland H.; Lehmann, Kuno; Sartori, Alessandro A.; Moch, Holger; Knuth, Alexander

    2011-01-01

    Background γ-radiation is an effective treatment for cancer. There is evidence that radiotherapy supports tumor-specific immunity. It was described that irradiation induces de novo protein synthesis and enhances antigen presentation, we therefore investigated whether γ-radiation results in increased expression of cancer-testis (CT) antigens and MHC-I, thus allowing efficient immunological control. This is relevant because the expression of CT-antigens and MHC-I on tumor cells is often heterogeneous. We found that the changes induced by γ-radiation promote the immunological recognition of the tumor, which is illustrated by the increased infiltration by lymphocytes after radiotherapy. Methods/Findings We compared the expression of CT-antigens and MHC-I in various cancer cell lines and fresh biopsies before and after in vitro irradiation (20 Gy). Furthermore, we compared paired biopsies that were taken before and after radiotherapy from sarcoma patients. To investigate whether the changed expression of CT-antigens and MHC-I is specific for γ-radiation or is part of a generalized stress response, we analyzed the effect of hypoxia, hyperthermia and genotoxic stress on the expression of CT-antigens and MHC-I. In vitro irradiation of cancer cell lines and of fresh tumor biopsies induced a higher or de novo expression of different CT-antigens and a higher expression of MHC-I in a time- and dose-dependent fashion. Importantly, we show that irradiation of cancer cells enhances their recognition by tumor-specific CD8+ T cells. The analysis of paired biopsies taken from a cohort of sarcoma patients before and after radiotherapy confirmed our findings and, in addition showed that irradiation resulted in higher infiltration by lymphocytes. Other forms of stress did not have an impact on the expression of CT-antigens or MHC-I. Conclusions Our findings suggest that γ-radiation promotes the immunological recognition of the tumor. We therefore propose that combining

  14. Antigen recognition. V. Requirement for histocompatibility between antigen-presenting cell and B cell in the response to a thymus- dependent antigen, and lack of allogeneic restriction between T and B cells

    PubMed Central

    1981-01-01

    The restrictions imposed by the major histocompatibility complex on T-B- antigen-presenting cell (APC) interactions were studied with an in vivo adoptive transfer system, using mutually tolerant T and B cells taken from one-way fetal liver chimeras. It was found that the B cells and adoptive recipient (which provides APC function) have to share determinants encoded by the left-hand end of the H-2 complex for cooperation, whereas there is apparently no such requirement for T-B cell syngeneicity. Suppression arising from allogeneic effects between the host and the transferred T or B cells was excluded by the use of tolerant as well as normal adoptive recipients; both were functionally equivalent. We conclude that under experimental conditions, unrestricted helper T cell function and concurrent APC-B cell genetic restriction can be demonstrated in vivo. PMID:7276826

  15. Recognition of tumor antigens in 4T1 cells by natural IgM from three strains of mice with different susceptibilities to spontaneous breast cancer

    PubMed Central

    Díaz-Zaragoza, Mariana; Hernández-Ávila, Ricardo; Ostoa-Saloma, Pedro

    2017-01-01

    The issue of antibody responses to tumors is potentially important to cancer immunologists. Early detection of cancer represents one of the most promising approaches to reduce the growing cancer burden. Natural immunoglobulin (Ig)M antibodies have been associated with the recognition and elimination of cancerous and precancerous cells. Using natural IgM antibodies, the present study identified a set of antigens in healthy mice from three different strains and examined whether the global patterns of antibodies are able to discriminate between a condition of more or less susceptibility to breast cancer. The current study performed two-dimensional (2D) immunoblotting to detect antigens from 4T1 cells using natural IgM from serum of healthy female mice from three different strains. The t-test was used to analyze the total number of spots. There were no significant differences in the numbers of antigens recognized in each strain. However, differences in patterns were observed on 2D immunoblots among the three strains. The reactivity patterns of natural IgM antibodies to particular antigens exhibited non-random clustering, which discriminated between strains with different susceptibilities to spontaneous breast cancer. The results demonstrated that the patterns of reactivity to defined subsets of antigens are able to provide information regarding differential diagnosis associated with breast cancer sensitivity. Therefore, it may be concluded that it is possible to segregate the IgM humoral immune response toward cancer antigens according to the genetic background of individuals. In addition, it is possible to identify the recognized antigens that allow grouping or discriminate between the different IgM antibodies expressed. The possible association between a particular antigen and cancer susceptibility requires further study, but the methodology exposed in the present study may identify potential candidates for this possible association. PMID:28123554

  16. Recognition sites for microbes and components of the immune system on human mast cells: relationship to CD antigens and implications for host defense.

    PubMed

    Mayerhofer, M; Aichberger, K J; Florian, S; Valent, P

    2007-01-01

    Traditionally, mast cells (MCs) have been considered to play an important role in allergic disorders and helminth infections. More recently, MCs have been implicated in a variety of different infectious diseases including life-threatening disorders caused by viruses and bacteria. Apart from recognition through specific IgE, MCs are considered to recognize such bacteria and viruses via specific cell surface binding sites. In addition, MCs interact with diverse components and cells of the immune system and thereby may facilitate the targeting and the elimination of invading microbes in the tissues. The current article provides an overview on MC antigens contributing to microbe recognition and targeting as an important element of natural host-defense.

  17. Multiple mechanisms underlie defective recognition of melanoma cells cultured in three-dimensional architectures by antigen-specific cytotoxic T lymphocytes

    PubMed Central

    Feder-Mengus, C; Ghosh, S; Weber, W P; Wyler, S; Zajac, P; Terracciano, L; Oertli, D; Heberer, M; Martin, I; Spagnoli, G C; Reschner, A

    2007-01-01

    Cancer cells' growth in three-dimensional (3D) architectures promotes resistance to drugs, cytokines, or irradiation. We investigated effects of 3D culture as compared to monolayers (2D) on melanoma cells' recognition by tumour-associated antigen (TAA)-specific HLA-A*0201-restricted cytotoxic T-lymphocytes (CTL). Culture of HBL, D10 (both HLA-A*0201+, TAA+) and NA8 (HLA-A*0201+, TAA−) melanoma cells on polyHEMA-coated plates, resulted in generation of 3D multicellular tumour spheroids (MCTS). Interferon-gamma (IFN-γ) production by HLA-A*0201-restricted Melan-A/MART-127–35 or gp100280–288-specific CTL clones served as immunorecognition marker. Co-culture with melanoma MCTS, resulted in defective TAA recognition by CTL as compared to 2D as witnessed by decreased IFN-γ production and decreased Fas Ligand, perforin and granzyme B gene expression. A multiplicity of mechanisms were potentially involved. First, MCTS per se limit CTL capacity of recognising HLA class I restricted antigens by reducing exposed cell surfaces. Second, expression of melanoma differentiation antigens is downregulated in MCTS. Third, expression of HLA class I molecules can be downregulated in melanoma MCTS, possibly due to decreased interferon-regulating factor-1 gene expression. Fourth, lactic acid production is increased in MCTS, as compared to 2D. These data suggest that melanoma cells growing in 3D, even in the absence of immune selection, feature characteristics capable of dramatically inhibiting TAA recognition by specific CTL. PMID:17342088

  18. Rational antigen modification as a strategy to upregulate or downregulate antigen recognition.

    PubMed

    Abrams, S I; Schlom, J

    2000-02-01

    Recent and rapid advances in our understanding of the cellular and molecular mechanisms of antigen recognition by CD8(+) and CD4(+) T lymphocytes have led to the birth of possibilities for site-directed, rational modification of cognate antigenic determinants. This immunologic concept has vast biomedical implications for regulation of host immunity against the pathogenesis of diverse disease processes. The upregulation of antigen-specific T-cell responses by 'agonistic' peptides would be most desirable in response to invasive pathogenic challenges, such as infectious and neoplastic disease, while the downregulation of antigen-specific T-cell responses by 'antagonistic' peptides would be most efficacious during inappropriate pathologic consequences, such as autoimmunity. The capacity to experimentally manipulate intrinsic properties of cognate peptide ligands to appropriately alter the nature, course and potency of cellular immune interactions has important potential in both preventive and therapeutic clinical paradigms.

  19. Proliferation of thymic stem cells with and without receptors for interleukin 2. Implications for intrathymic antigen recognition

    PubMed Central

    1985-01-01

    We have tested the dividing cells in the mouse thymus for expression of interleukin 2 (IL-2) receptors (IL-2-R) using the rat monoclonal antibody 7D4. A discrete subpopulation of the lymphoblasts clearly expressed IL-2-R at levels comparable to those on mitogen-activated peripheral T cells. This subpopulation, however, represented a small minority of the proliferating cells. IL-2-R-bearing cells were depleted from the PNA+ (peanut agglutinin) lymphoblast population, which contains the direct precursors of most of the cells in the thymus. The majority of receptor-bearing cells were found in the PNA- lymphoblast population, where they constituted only approximately 12% of the cells. Thus, virtually all the PNA+ and most of the PNA- blast cells were in cycle without detectable IL-2-R expression. This indicates that they were not dividing in response to IL-2, and implies that they were not dividing in response to antigen, but rather to novel thymus-specific mitogenic stimuli. On the other hand, the proliferating cells that do express IL-2-R were enriched 4-5-fold in the rapidly growing neonatal thymus, suggesting that they may also play a key role in T cell development. PMID:3921650

  20. The Dynamics of the Human Leukocyte Antigen Head Domain Modulates Its Recognition by the T-Cell Receptor.

    PubMed

    García-Guerrero, Estefanía; Pérez-Simón, José Antonio; Sánchez-Abarca, Luis Ignacio; Díaz-Moreno, Irene; De la Rosa, Miguel A; Díaz-Quintana, Antonio

    2016-01-01

    Generating the immune response requires the discrimination of peptides presented by the human leukocyte antigen complex (HLA) through the T-cell receptor (TCR). However, how a single amino acid substitution in the antigen bonded to HLA affects the response of T cells remains uncertain. Hence, we used molecular dynamics computations to analyze the molecular interactions between peptides, HLA and TCR. We compared immunologically reactive complexes with non-reactive and weakly reactive complexes. MD trajectories were produced to simulate the behavior of isolated components of the various p-HLA-TCR complexes. Analysis of the fluctuations showed that p-HLA binding barely restrains TCR motions, and mainly affects the CDR3 loops. Conversely, inactive p-HLA complexes displayed significant drop in their dynamics when compared with its free versus ternary forms (p-HLA-TCR). In agreement, the free non-reactive p-HLA complexes showed a lower amount of salt bridges than the responsive ones. This resulted in differences between the electrostatic potentials of reactive and inactive p-HLA species and larger vibrational entropies in non-elicitor complexes. Analysis of the ternary p-HLA-TCR complexes also revealed a larger number of salt bridges in the responsive complexes. To summarize, our computations indicate that the affinity of each p-HLA complex towards TCR is intimately linked to both, the dynamics of its free species and its ability to form specific intermolecular salt-bridges in the ternary complexes. Of outstanding interest is the emerging concept of antigen reactivity involving its interplay with the HLA head sidechain dynamics by rearranging its salt-bridges.

  1. The Dynamics of the Human Leukocyte Antigen Head Domain Modulates Its Recognition by the T-Cell Receptor

    PubMed Central

    García-Guerrero, Estefanía; Pérez-Simón, José Antonio; Sánchez-Abarca, Luis Ignacio; Díaz-Moreno, Irene; De la Rosa, Miguel A.; Díaz-Quintana, Antonio

    2016-01-01

    Generating the immune response requires the discrimination of peptides presented by the human leukocyte antigen complex (HLA) through the T-cell receptor (TCR). However, how a single amino acid substitution in the antigen bonded to HLA affects the response of T cells remains uncertain. Hence, we used molecular dynamics computations to analyze the molecular interactions between peptides, HLA and TCR. We compared immunologically reactive complexes with non-reactive and weakly reactive complexes. MD trajectories were produced to simulate the behavior of isolated components of the various p-HLA-TCR complexes. Analysis of the fluctuations showed that p-HLA binding barely restrains TCR motions, and mainly affects the CDR3 loops. Conversely, inactive p-HLA complexes displayed significant drop in their dynamics when compared with its free versus ternary forms (p-HLA-TCR). In agreement, the free non-reactive p-HLA complexes showed a lower amount of salt bridges than the responsive ones. This resulted in differences between the electrostatic potentials of reactive and inactive p-HLA species and larger vibrational entropies in non-elicitor complexes. Analysis of the ternary p-HLA-TCR complexes also revealed a larger number of salt bridges in the responsive complexes. To summarize, our computations indicate that the affinity of each p-HLA complex towards TCR is intimately linked to both, the dynamics of its free species and its ability to form specific intermolecular salt-bridges in the ternary complexes. Of outstanding interest is the emerging concept of antigen reactivity involving its interplay with the HLA head sidechain dynamics by rearranging its salt-bridges. PMID:27124285

  2. Cryptococcus gattii Capsule Blocks Surface Recognition Required for Dendritic Cell Maturation Independent of Internalization and Antigen Processing.

    PubMed

    Huston, Shaunna M; Ngamskulrungroj, Popchai; Xiang, Richard F; Ogbomo, Henry; Stack, Danuta; Li, Shu Shun; Timm-McCann, Martina; Kyei, Stephen K; Oykhman, Paul; Kwon-Chung, Kyung J; Mody, Christopher H

    2016-02-01

    Cryptococcus gattii is an emerging fungal pathogen on the west coast of Canada and the United States that causes a potentially fatal infection in otherwise healthy individuals. In previous investigations of the mechanisms by which C. gattii might subvert cell-mediated immunity, we found that C. gattii failed to induce dendritic cell (DC) maturation, leading to defective T cell responses. However, the virulence factor and the mechanisms of evasion of DC maturation remain unknown. The cryptococcal polysaccharide capsule is a leading candidate because of its antiphagocytic properties. Consequently, we asked if the capsule of C. gattii was involved in evasion of DC maturation. We constructed an acapsular strain of C. gattii through CAP59 gene deletion by homologous integration. Encapsulated C. gattii failed to induce human monocyte-derived DC maturation and T cell proliferation, whereas the acapsular mutant induced both processes. Surprisingly, encapsulation impaired DC maturation independent of its effect on phagocytosis. Indeed, DC maturation required extracellular receptor signaling that was dependent on TNF-α and p38 MAPK, but not ERK activation, and the cryptococcal capsule blocked this extracellular recognition. Although the capsule impaired phagocytosis that led to pH-dependent serine-, threonine-, and cysteine-sensitive protease-dependent Ag processing, it was insufficient to impair T cell responses. In summary, C. gattii affects two independent processes, leading to DC maturation and Ag processing. The polysaccharide capsule masked extracellular detection and reduced phagocytosis that was required for DC maturation and Ag processing, respectively. However, the T cell response was fully restored by inducing DC maturation.

  3. Regression of human kidney cancer following allogeneic stem cell transplantation is associated with recognition of an HERV-E antigen by T cells

    PubMed Central

    Takahashi, Yoshiyuki; Harashima, Nanae; Kajigaya, Sachiko; Yokoyama, Hisayuki; Cherkasova, Elena; McCoy, J. Philip; Hanada, Ken-ichi; Mena, Othon; Kurlander, Roger; Abdul, Tawab; Srinivasan, Ramaprasad; Lundqvist, Andreas; Malinzak, Elizabeth; Geller, Nancy; Lerman, Michael I.; Childs, Richard W.

    2008-01-01

    Transplanted donor lymphocytes infused during hematopoietic stem cell transplantation (HSCT) have been shown to cure patients with hematological malignancies. However, less is known about the effects of HSCT on metastatic solid tumors. Thus, a better understanding of the immune cells and their target antigens that mediate tumor regression is urgently needed to develop more effective HSCT approaches for solid tumors. Here we report regression of metastatic renal cell carcinoma (RCC) in patients following nonmyeloablative HSCT consistent with a graft-versus-tumor effect. We detected RCC-reactive donor-derived CD8+ T cells in the blood of patients following nonmyeloablative HSCT. Using cDNA expression cloning, we identified a 10-mer peptide (CT-RCC-1) as a target antigen of RCC-specific CD8+ T cells. The genes encoding this antigen were found to be derived from human endogenous retrovirus (HERV) type E and were expressed in RCC cell lines and fresh RCC tissue but not in normal kidney or other tissues. We believe this to be the first solid tumor antigen identified using allogeneic T cells from a patient undergoing HSCT. These data suggest that HERV-E is activated in RCC and that it encodes an overexpressed immunogenic antigen, therefore providing a potential target for cellular immunity. PMID:18292810

  4. Direct role for proliferating cell nuclear antigen in substrate recognition by the E3 ubiquitin ligase CRL4Cdt2.

    PubMed

    Havens, Courtney G; Shobnam, Nadia; Guarino, Estrella; Centore, Richard C; Zou, Lee; Kearsey, Stephen E; Walter, Johannes C

    2012-03-30

    The E3 ubiquitin ligase Cullin-ring ligase 4-Cdt2 (CRL4(Cdt2)) is emerging as an important cell cycle regulator that targets numerous proteins for destruction in S phase and after DNA damage, including Cdt1, p21, and Set8. CRL4(Cdt2) substrates contain a "PIP degron," which consists of a canonical proliferating cell nuclear antigen (PCNA) interaction motif (PIP box) and an adjacent basic amino acid. Substrates use their PIP box to form a binary complex with PCNA on chromatin and the basic residue to recruit CRL4(Cdt2) for substrate ubiquitylation. Using Xenopus egg extracts, we identify an acidic residue in PCNA that is essential to support destruction of all CRL4(Cdt2) substrates. This PCNA residue, which adjoins the basic amino acid of the bound PIP degron, is dispensable for substrate binding to PCNA but essential for CRL4(Cdt2) recruitment to chromatin. Our data show that the interaction of CRL4(Cdt2) with substrates requires molecular determinants not only in the substrate degron but also on PCNA. The results illustrate a potentially general mechanism by which E3 ligases can couple ubiquitylation to the formation of protein-protein interactions.

  5. Structures of MART-126/27-35Peptide/HLA-A2 Complexes Reveal a Remarkable Disconnect between Antigen Structural Homology and T Cell Recognition

    SciTech Connect

    Borbulevych, Oleg Y; Insaidoo, Francis K; Baxter, Tiffany K; Powell, Jr., Daniel J.; Johnson, Laura A; Restifo, Nicholas P; Baker, Brian M

    2008-09-17

    Small structural changes in peptides presented by major histocompatibility complex (MHC) molecules often result in large changes in immunogenicity, supporting the notion that T cell receptors are exquisitely sensitive to antigen structure. Yet there are striking examples of TCR recognition of structurally dissimilar ligands. The resulting unpredictability of how T cells will respond to different or modified antigens impacts both our understanding of the physical bases for TCR specificity as well as efforts to engineer peptides for immunomodulation. In cancer immunotherapy, epitopes and variants derived from the MART-1/Melan-A protein are widely used as clinical vaccines. Two overlapping epitopes spanning amino acid residues 26 through 35 are of particular interest: numerous clinical studies have been performed using variants of the MART-1 26-35 decamer, although only the 27-35 nonamer has been found on the surface of targeted melanoma cells. Here, we show that the 26-35 and 27-35 peptides adopt strikingly different conformations when bound to HLA-A2. Nevertheless, clonally distinct MART-1{sub 26/27-35}-reactive T cells show broad cross-reactivity towards these ligands. Simultaneously, however, many of the cross-reactive T cells remain unable to recognize anchor-modified variants with very subtle structural differences. These dichotomous observations challenge our thinking about how structural information on unligated peptide/MHC complexes should be best used when addressing questions of TCR specificity. Our findings also indicate that caution is warranted in the design of immunotherapeutics based on the MART-1 26/27-35 epitopes, as neither cross-reactivity nor selectivity is predictable based on the analysis of the structures alone.

  6. Limited HLA sequence variation outside of antigen recognition domain exons of 360 10 of 10 matched unrelated hematopoietic stem cell transplant donor-recipient pairs.

    PubMed

    Hou, L; Vierra-Green, C; Lazaro, A; Brady, C; Haagenson, M; Spellman, S; Hurley, C K

    2017-01-01

    Traditional DNA-based typing focuses primarily on interrogating the exons of human leukocyte antigen (HLA) genes that form the antigen recognition domain (ARD). The relevance of mismatching donor and recipient for HLA variation outside the ARD on hematopoietic stem cell transplantation (HSCT) outcomes is unknown. This study was designed to evaluate the frequency of variation outside the ARD in 10 of 10 (HLA-A, -B, -C, -DRB1, -DQB1) matched unrelated donor transplant pairs (n = 360). Next-generation DNA sequencing was used to characterize both HLA exons and introns for HLA-A, -B, -C alleles; exons 2, 3 and the intervening intron for HLA-DRB1 and exons only for HLA-DQA1 and -DQB1. Over 97% of alleles at each locus were matched for their nucleotide sequence outside of the ARD exons. Of the 4320 allele comparisons overall, only 17 allele pairs were mismatched for non-ARD exons, 41 for noncoding regions and 9 for ARD exons. The observed variation between donor and recipient usually involved a single nucleotide difference (88% of mismatches); 88% of the non-ARD exon variants impacted the amino acid sequence. The impact of amino acid sequence variation caused by substitutions in exons outside ARD regions in D-R pairs will be difficult to assess in HSCT outcome studies because these mismatches do not occur very frequently.

  7. Dominant recognition of a cross-reactive B-cell epitope in Mycobacterium leprae 10 K antigen by immunoglobulin G1 antibodies across the disease spectrum in leprosy

    PubMed Central

    Hussain, R; Dockrell, H M; Chiang, T J

    1999-01-01

    Mycobacterium leprae-specific immunoglobulin G1 (IgG1) antibodies in patients with leprosy show a direct correlation with bacterial load (ρ=0·748; P < 0002) suggesting that IgG1 B-cell responses may be surrogate markers of disease progression. To investigate if this upregulation was a general feature of IgG1 responses to all M. leprae (ML) antigens, we analysed responses to several recombinant purified ML heat-shock proteins (HSP). Three recombinant HSPs (ML10 K, ML 18 K and ML 65 K) were tested for their ability to induce various IgG subclasses in patients with either the lepromatous (LL/BL, n = 26) or tuberculoid form (BT/TT, n = 39) of the disease as well as in healthy households (HC, n = 14) and endemic controls (EC = 19). Our major findings were: (1) selective augmentation of IgG1 antibody responses to ML10 K; (2) recognition of a restricted number of epitopes across the disease spectrum and healthy controls by IgG1 antibodies; (3) dominant recognition of cross-reactive epitopes which were common to both ML and MT 10 K. This response was not related to contamination with endotoxin. Epitope mapping using 15-mer overlapping peptides spanning the ML 10 000 MW revealed an immunodominant IgG1 binding peptide (aa41–55) in patients as well as healthy controls. This peptide is a shared epitope with M. tuberculosis 10 K suggesting that postswitched IgG1 B cells recognizing this epitope rather than naive B cells are being expanded. PMID:10233750

  8. Coexpression of PD-1, 2B4, CD160 and KLRG1 on exhausted HCV-specific CD8+ T cells is linked to antigen recognition and T cell differentiation.

    PubMed

    Bengsch, Bertram; Seigel, Bianca; Ruhl, Marianne; Timm, Jörg; Kuntz, Martin; Blum, Hubert E; Pircher, Hanspeter; Thimme, Robert

    2010-06-10

    Exhausted CD8+ T cell responses during chronic viral infections are defined by a complex expression pattern of inhibitory receptors. However, very little information is currently available about the coexpression patterns of these receptors on human virus-specific CD8+ T cells and their correlation with antiviral functions, T cell differentiation and antigen recognition. We addressed these important aspects in a cohort of 38 chronically HCV infected patients and found a coexpression of inhibitory receptors such as 2B4, CD160 and KLRG1 in association with PD-1 in about half of the HCV-specific CD8+ T cell responses. Importantly, this exhaustive phenotype was associated with low and intermediate levels of CD127 expression, an impaired proliferative capacity, an intermediate T cell differentiation stage and absence of sequence variations within the corresponding epitopes, indicating ongoing antigen triggering. In contrast, a low expression of inhibitory receptors by the remaining HCV-specific CD8+ T cells occurred in concert with a CD127hi phenotype, an early T cell differentiation stage and presence of viral sequence variations within the corresponding epitopes. In sum, these results suggest that T cell exhaustion contributes to the failure of about half of HCV-specific CD8+ T cell responses and that it is determined by a complex interplay of immunological (e.g. T cell differentiation) and virological (e.g. ongoing antigen triggering) factors.

  9. Substrate recognition by the Lyn protein-tyrosine kinase. NMR structure of the immunoreceptor tyrosine-based activation motif signaling region of the B cell antigen receptor.

    PubMed

    Gaul, B S; Harrison, M L; Geahlen, R L; Burton, R A; Post, C B

    2000-05-26

    The immunoreceptor tyrosine-based activation motif (ITAM) plays a central role in transmembrane signal transduction in hematopoietic cells by mediating responses leading to proliferation and differentiation. An initial signaling event following activation of the B cell antigen receptor is phosphorylation of the CD79a (Ig-alpha) ITAM by Lyn, a Src family protein-tyrosine kinase. To elucidate the structural basis for recognition between the ITAM substrate and activated Lyn kinase, the structure of an ITAM-derived peptide bound to Lyn was determined using exchange-transferred nuclear Overhauser NMR spectroscopy. The bound substrate structure has an irregular helix-like character. Docking based on the NMR data into the active site of the closely related Lck kinase strongly favors ITAM binding in an orientation similar to binding of cyclic AMP-dependent protein kinase rather than that of insulin receptor tyrosine kinase. The model of the complex provides a rationale for conserved ITAM residues, substrate specificity, and suggests that substrate binds only the active conformation of the Src family tyrosine kinase, unlike the ATP cofactor, which can bind the inactive form.

  10. Natural micropolymorphism in human leukocyte antigens provides a basis for genetic control of antigen recognition

    SciTech Connect

    Archbold, Julia K.; Macdonald, Whitney A.; Gras, Stephanie; Ely, Lauren K.; Miles, John J.; Bell, Melissa J.; Brennan, Rebekah M.; Beddoe, Travis; Wilce, Matthew C.J.; Clements, Craig S.; Purcell, Anthony W.; McCluskey, James; Burrows, Scott R.; Rossjohn, Jamie

    2009-07-10

    Human leukocyte antigen (HLA) gene polymorphism plays a critical role in protective immunity, disease susceptibility, autoimmunity, and drug hypersensitivity, yet the basis of how HLA polymorphism influences T cell receptor (TCR) recognition is unclear. We examined how a natural micropolymorphism in HLA-B44, an important and large HLA allelic family, affected antigen recognition. T cell-mediated immunity to an Epstein-Barr virus determinant (EENLLDFVRF) is enhanced when HLA-B*4405 was the presenting allotype compared with HLA-B*4402 or HLA-B*4403, each of which differ by just one amino acid. The micropolymorphism in these HLA-B44 allotypes altered the mode of binding and dynamics of the bound viral epitope. The structure of the TCR-HLA-B*4405EENLLDFVRF complex revealed that peptide flexibility was a critical parameter in enabling preferential engagement with HLA-B*4405 in comparison to HLA-B*4402/03. Accordingly, major histocompatibility complex (MHC) polymorphism can alter the dynamics of the peptide-MHC landscape, resulting in fine-tuning of T cell responses between closely related allotypes.

  11. Podosomes of dendritic cells facilitate antigen sampling

    PubMed Central

    Reinieren-Beeren, Inge; Cambi, Alessandra; Figdor, Carl G.; van den Bogaart, Geert

    2014-01-01

    Summary Dendritic cells sample the environment for antigens and play an important role in establishing the link between innate and acquired immunity. Dendritic cells contain mechanosensitive adhesive structures called podosomes that consist of an actin-rich core surrounded by integrins, adaptor proteins and actin network filaments. They facilitate cell migration via localized degradation of extracellular matrix. Here we show that podosomes of human dendritic cells locate to spots of low physical resistance in the substrate (soft spots) where they can evolve into protrusive structures. Pathogen recognition receptors locate to these protrusive structures where they can trigger localized antigen uptake, processing and presentation to activate T-cells. Our data demonstrate a novel role in antigen sampling for podosomes of dendritic cells. PMID:24424029

  12. Podosomes of dendritic cells facilitate antigen sampling.

    PubMed

    Baranov, Maksim V; Ter Beest, Martin; Reinieren-Beeren, Inge; Cambi, Alessandra; Figdor, Carl G; van den Bogaart, Geert

    2014-03-01

    Dendritic cells sample the environment for antigens and play an important role in establishing the link between innate and acquired immunity. Dendritic cells contain mechanosensitive adhesive structures called podosomes that consist of an actin-rich core surrounded by integrins, adaptor proteins and actin network filaments. They facilitate cell migration via localized degradation of extracellular matrix. Here, we show that podosomes of human dendritic cells locate to spots of low physical resistance in the substrate (soft spots) where they can evolve into protrusive structures. Pathogen recognition receptors locate to these protrusive structures where they can trigger localized antigen uptake, processing and presentation to activate T-cells. Our data demonstrate a novel role in antigen sampling for the podosomes of dendritic cells.

  13. Nonclassical antigen-processing pathways are required for MHC class II-restricted direct tumor recognition by NY-ESO-1-specific CD4(+) T cells.

    PubMed

    Matsuzaki, Junko; Tsuji, Takemasa; Luescher, Immanuel; Old, Lloyd J; Shrikant, Protul; Gnjatic, Sacha; Odunsi, Kunle

    2014-04-01

    Tumor antigen-specific CD4(+) T cells that directly recognize cancer cells are important for orchestrating antitumor immune responses at the local tumor sites. However, the mechanisms of direct MHC class II (MHC-II) presentation of intracellular tumor antigen by cancer cells are poorly understood. We found that two functionally distinct subsets of CD4(+) T cells were expanded after HLA-DPB1*04 (DP04)-binding NY-ESO-1157-170 peptide vaccination in patients with ovarian cancer. Although both subsets recognized exogenous NY-ESO-1 protein pulsed on DP04(+) target cells, only one type recognized target cells with intracellular expression of NY-ESO-1. The tumor-recognizing CD4(+) T cells more efficiently recognized the short 8-9-mer peptides than the non-tumor-recognizing CD4(+) T cells. In addition to endosomal/lysosomal proteases that are typically involved in MHC-II antigen presentation, several pathways in the MHC class I presentation pathways, such as the proteasomal degradation and transporter-associated with antigen-processing-mediated peptide transport, were also involved in the presentation of intracellular NY-ESO-1 on MHC-II. The presentation was inhibited significantly by primaquine, a small molecule that inhibits endosomal recycling, consistent with findings that pharmacologic inhibition of new protein synthesis enhances antigen presentation. Together, our data demonstrate that cancer cells selectively present peptides from intracellular tumor antigens on MHC-II by multiple nonclassical antigen-processing pathways. Harnessing the direct tumor-recognizing ability of CD4(+) T cells could be a promising strategy to enhance antitumor immune responses in the immunosuppressive tumor microenvironment.

  14. Loss of T Cell Antigen Recognition Arising from Changes in Peptide and Major Histocompatibility Complex Protein Flexibility: Implications for Vaccine Design

    SciTech Connect

    Insaidoo, Francis K.; Borbulevych, Oleg Y.; Hossain, Moushumi; Santhanagopolan, Sujatha M.; Baxter, Tiffany K.; Baker, Brian M.

    2012-05-08

    Modification of the primary anchor positions of antigenic peptides to improve binding to major histocompatibility complex (MHC) proteins is a commonly used strategy for engineering peptide-based vaccine candidates. However, such peptide modifications do not always improve antigenicity, complicating efforts to design effective vaccines for cancer and infectious disease. Here we investigated the MART-1{sub 27-35} tumor antigen, for which anchor modification (replacement of the position two alanine with leucine) dramatically reduces or ablates antigenicity with a wide range of T cell clones despite significantly improving peptide binding to MHC. We found that anchor modification in the MART-1{sub 27-35} antigen enhances the flexibility of both the peptide and the HLA-A*0201 molecule. Although the resulting entropic effects contribute to the improved binding of the peptide to MHC, they also negatively impact T cell receptor binding to the peptide {center_dot} MHC complex. These results help explain how the 'anchor-fixing' strategy fails to improve antigenicity in this case, and more generally, may be relevant for understanding the high specificity characteristic of the T cell repertoire. In addition to impacting vaccine design, modulation of peptide and MHC flexibility through changes to antigenic peptides may present an evolutionary strategy for the escape of pathogens from immune destruction.

  15. TL antigen as a transplantation antigen recognized by TL-restricted cytotoxic T cells

    PubMed Central

    1994-01-01

    In contrast to broadly expressed classical class I antigens of the major histocompatibility complex, structurally closely related TL antigens are expressed in a highly restricted fashion. Unlike classical class I antigens, TL antigens are not known to be targets of cytotoxic T cells or to mediate graft rejection. Whereas classical class I antigens function as antigen-presenting molecules to T cell receptors (TCR), the role of TL is yet to be defined. To elucidate the function of TL, we have derived transgenic mice expressing TL in most tissues including skin by introducing a TL gene, T3b of C57BL/6 mouse origin, driven by the H-2Kb promoter. By grafting the skin of transgenic mice, we demonstrate that TL can serve as a transplantation antigen and mediate a TCR-alpha/beta+ CD8+ cytotoxic T cell response. This T cell recognition of TL does not require antigen presentation by H-2 molecules. Furthermore, we show that C57BL/6 F1 mice develop CD8+ T cells that are cytotoxic for C57BL/6 TL+ leukemia cells, providing further support for the concept that aberrantly expressed nonmutated proteins such as TL can be recognized as tumor antigens. PMID:8113675

  16. Specific T-cell recognition of the merozoite proteins rhoptry-associated protein 1 and erythrocyte-binding antigen 1 of Plasmodium falciparum.

    PubMed Central

    Jakobsen, P H; Hviid, L; Theander, T G; Afare, E A; Ridley, R G; Heegaard, P M; Stuber, D; Dalsgaard, K; Nkrumah, F K

    1993-01-01

    The merozoite proteins merozoite surface protein 1 (MSP-1) and rhoptry-associated protein 1 (RAP-1) and synthetic peptides containing sequences of MSP-1, RAP-1, and erythrocyte-binding antigen 1, induced in vitro proliferative responses of lymphocytes collected from Ghanaian blood donors living in an area with a high rate of transmission of malaria. Lymphocytes from a large proportion of the Ghanaian blood donors proliferated in response to the RAP-1 peptide, unlike those of Danish control blood donors, indicating that this sequence contains a malaria-specific T-cell epitope broadly recognized by individuals living in an area with a high transmission rate of malaria. Most of the donor plasma samples tested contained immunoglobulin G (IgG) and IgM antibodies recognizing the merozoite proteins, while only a minority showed high IgG reactivity to the synthetic peptides. PMID:8418048

  17. Kinetics of T-cell receptor-dependent antigen recognition determined in vivo by multi-spectral normalized epifluorescence laser scanning

    NASA Astrophysics Data System (ADS)

    Favicchio, Rosy; Zacharakis, Giannis; Oikonomaki, Katerina; Zacharopoulos, Athanasios; Mamalaki, Clio; Ripoll, Jorge

    2012-07-01

    Detection of multiple fluorophores in conditions of low signal represents a limiting factor for the application of in vivo optical imaging techniques in immunology where fluorescent labels report for different functional characteristics. A noninvasive in vivo Multi-Spectral Normalized Epifluorescence Laser scanning (M-SNELS) method was developed for the simultaneous and quantitative detection of multiple fluorophores in low signal to noise ratios and used to follow T-cell activation and clonal expansion. Colocalized DsRed- and GFP-labeled T cells were followed in tandem during the mounting of an immune response. Spectral unmixing was used to distinguish the overlapping fluorescent emissions representative of the two distinct cell populations and longitudinal data reported the discrete pattern of antigen-driven proliferation. Retrieved values were validated both in vitro and in vivo with flow cytometry and significant correlation between all methodologies was achieved. Noninvasive M-SNELS successfully quantified two colocalized fluorescent populations and provides a valid alternative imaging approach to traditional invasive methods for detecting T cell dynamics.

  18. Generalized immunological recognition of the major merozoite surface antigen (gp195) of Plasmodium falciparum

    SciTech Connect

    Chang, S.P.; Hui, G.S.N.; Kato, A.; Siddiqui, W.A. )

    1989-08-01

    The antibody response to the Plasmodium falciparum major merozoite surface antigen (gp195) of congenic mouse strains differing in H-2 haplotype has been examined. All seven strains of mice were capable of producing gp195-specific antibodies. Generalized immune recognition of gp195 by mice of diverse H-2 haplotypes distinguished gp195 from the P. falciparum circumsporozoite protein and the 230-kDa and 48/45-kDa gamete surface antigens. However, the H-2 genetic locus appeared to influence the specificity of gp105-specific antibodies. Immunoblot patterns of mouse sera with parasite antigens revealed a complex pattern of reactivity with terminal and intermediate processing fragments of gp195. The majority of immunoblot bands observed were similar for all of the mouse strains; however, there were several strains that additionally recognized a few unique fragments or displayed more intense reactivities with specific processing fragments. These results suggest that while individuals of diverse major histocompatibility complex makeup are capable of recognizing the gp195 antigen, the recognition of specific gp195 B-cell and T-cell epitopes may be under control of the major histocompatibility complex.

  19. Efficient generation of B lymphocytes by recognition of self-antigens

    PubMed Central

    Eschbach, Cathrin; Bach, Martina P.; Fidler, Ingrid; Pelanda, Roberta; Köhler, Fabian; Rajewsky, Klaus; Jumaa, Hassan

    2012-01-01

    Antibody diversity is generated by a random gene recombination process with the inherent risk of the production of autoreactive specificities. The current view suggests that B cells expressing such specificities are negatively selected at an early developmental stage. Using the knock-in model system of the 3–83 autoreactive B-cell antigen receptor (BCR) in combination with precursor-BCR (pre-BCR) deficiency, we show here that the 3–83 BCR mediates efficient generation of B cells in the presence, but not the absence, of a strongly recognized auto-antigen. Experiments with mixed bone marrow chimeras showed that combining the 3–83 BCR with the corresponding auto-antigen resulted in efficient reconstitution of B-cell development in immune-deficient mice. These results suggest that B cells are positively selected by recognition of self-antigens during developmental stages that precede receptor editing. Moreover, the data indicate that the pre- BCR functions as a specialized autoreactive BCR to initiate positive selection at a stage where the cells express immunoglobulin heavy but not light chains. PMID:21604259

  20. Photoaffinity antigens for human γδ T cells1

    PubMed Central

    Sarikonda, Ghanashyam; Wang, Hong; Puan, Kia-Joo; Liu, Xiao-hui; Lee, Hoi K.; Song, Yongcheng; Distefano, Mark D.; Oldfield, Eric; Prestwich, Glenn D.; Morita, Craig T.

    2009-01-01

    Vγ2Vδ2 T cells comprise the major subset of peripheral blood γ δ T cells in humans and expand during infections by recognizing small, nonpeptide prenyl pyrophosphates. These molecules include (E)-4-hydroxy-3-methyl-but-2-enyl-pyrophosphate (HMBPP), a microbial isoprenoid intermediate, and isopentenyl pyrophosphate (IPP), an endogenous isoprenoid intermediate. Recognition of these nonpeptide antigens is mediated by the Vγ2Vδ2 T cell antigen receptor (TCR). Several findings suggest that prenyl pyrophosphates are presented by an antigen presenting molecule: contact between T cells and APCs is required; the antigens do not bind the Vγ2Vδ2 TCR directly; and antigen recognition is abrogated by TCR mutations in CDRs distant from the putative antigen recognition site. Identification of the putative antigen presenting molecule, however, has been hindered by the inability to achieve stable association of nonpeptide prenyl pyrophosphate antigens with the presenting molecule. In this study, we show that photoaffinity analogs of HMBPP, meta/para-benzophenone-(methylene)-prenyl pyrophosphates (m/p-BZ-(C)-C5-OPP), can cross-link to the surface of tumor cell lines and be presented as antigens to γ δ T cells. Mutant tumor cell lines lacking MHC class I, MHC class II, β2-microglobulin, and CD1, as well as tumor cell lines from a variety of tissues and individuals, will all crosslink to and present m-BZ-C5-OPP. Finally, pulsing of BZ-(C)-C5-OPP is inhibited by IPP and an inactive analog, suggesting that they bind to the same molecule. Taken together, these results suggest that nonpeptide antigens are presented by a novel antigen presenting molecule that is widely distributed, non-polymorphic, but not classical MHC class I, MHC class II, or CD1. This is an author-produced version of a manuscript accepted for publication in The Journal of Immunology (The JI). The American Association of Immunologists, Inc. (AAI), publisher of The JI, holds the copyright to this manuscript

  1. Regulator T cells: specific for antigen and/or antigen receptors?

    PubMed

    Rubin, B; de Durana, Y Diaz; Li, N; Sercarz, E E

    2003-05-01

    Adaptive immune responses are regulated by many different molecular and cellular effectors. Regulator T cells are coming to their rights again, and these T cells seem to have ordinary alpha/beta T-cell receptors (TCRs) and to develop in the thymus. Autoimmune responses are tightly regulated by such regulatory T cells, a phenomenon which is beneficial to the host in autoimmune situations. However, the regulation of autoimmune responses to tumour cells is harmful to the host, as this regulation delays the defence against the outgrowth of neoplastic cells. In the present review, we discuss whether regulatory T cells are specific for antigen and/or for antigen receptors. Our interest in these phenomena comes from the findings that T cells produce many more TCR-alpha and TCR-beta chains than are necessary for surface membrane expression of TCR-alphabeta heterodimers with CD3 complexes. Excess TCR chains are degraded by the proteasomes, and TCR peptides thus become available to the assembly pathway of major histocompatibility complex class I molecules. Consequently, do T cells express two different identification markers on the cell membrane, the TCR-alphabeta clonotype for recognition by B-cell receptors and clonotypic TCR-alphabeta peptides for recognition by T cells?

  2. Intestinal Antigen-Presenting Cells

    PubMed Central

    Flannigan, Kyle L.; Geem, Duke; Harusato, Akihito; Denning, Timothy L.

    2016-01-01

    The microbiota that populate the mammalian intestine are critical for proper host physiology, yet simultaneously pose a potential danger. Intestinal antigen-presenting cells, namely macrophages and dendritic cells (DCs), are integral components of the mucosal innate immune system that maintain co-existence with the microbiota in face of this constant threat. Intestinal macrophages and DCs integrate signals from the microenvironment to orchestrate innate and adaptive immune responses that ultimately lead to durable tolerance of the microbiota. Tolerance is not a default response, however, because macrophages and DCs remain poised to vigorously respond to pathogens that breach the epithelial barrier. In this review, we summarize the salient features of macrophages and DCs in the healthy and inflamed intestine and discuss how signals from the microbiota can influence their function. PMID:25976247

  3. Antigen presentation by Hodgkin's disease cells.

    PubMed

    Fisher, R I; Cossman, J; Diehl, V; Volkman, D J

    1985-11-01

    The L428 tumor cell line is a long-term tissue culture of Reed-Sternberg cells which was derived from the pleural effusion of a patient with Hodgkin's disease. The L428 cells express all known cell surface antigens, cytochemical staining, and cytologic features of freshly explanted Reed-Sternberg cells. In addition to the previously described HLA-DR cell surface antigens, the L428 cells are now demonstrated to express both DS and SB alloantigens. Thus, the L428 cells express all of the known subclasses of the human immune response genes that are located in the major histocompatibility complex. Furthermore, the L428 cells are capable of presenting soluble antigen to T cells in a genetically restricted fashion. T cell lines were established from normal donors previously immunized with tetanus toxoid. The T cells utilized were incapable of tetanus toxoid-induced proliferation unless antigen-presenting cells were added to the cultures. However, T cells from the two normal donors, which like the L428 cells expressed HLA-DR 5, demonstrated significant proliferative responses when cultured with tetanus toxoid and L428 cells. No proliferative response was observed when the L428 cells were used as antigen-presenting cells for a DR (4,-), DR (2,-) or DR (1,7) T cell line. The tetanus toxoid dose-response curve was similar regardless of whether autologous mononuclear leukocytes or L428 cells were used as antigen-presenting cells. The T cell proliferation induced by soluble antigen was also blocked by anti-HLA-DR antibody. Thus, functionally, Hodgkin's disease may be classified as a tumor of antigen-presenting cells.

  4. HLA class II antigen presentation by prostate cancer cells.

    PubMed

    Younger, A R; Amria, S; Jeffrey, W A; Mahdy, A E M; Goldstein, O G; Norris, J S; Haque, A

    2008-01-01

    Prostate cancer is the second most commonly diagnosed cancer in men. Recent evidence suggests that reduced expression of target protein antigens and human leukocyte antigen (HLA) molecules is the predominant immune escape mechanism of malignant prostate tumor cells. The purpose of this study was to investigate the prospect of antigen specific immunotherapy against prostate cancer via the HLA class II pathway of immune recognition. Here, we show for the first time that prostate cancer cells express HLA class II proteins that are recognized by CD4+ T cells. Prostate tumor cells transduced with class II molecules efficiently presented tumor-associated antigens/peptides to CD4+ T cells. This data suggests that malignant prostate tumors can be targeted via the HLA class II pathway, and that class II-positive tumors could be employed for direct antigen presentation, and CD4+ T-cell mediated tumor immunotherapy.Prostate Cancer and Prostatic Diseases (2008) 11, 334-341; doi:10.1038/sj.pcan.4501021; published online 16 October 2007.

  5. Heat shock protein 90-mediated peptide-selective presentation of cytosolic tumor antigen for direct recognition of tumors by CD4(+) T cells.

    PubMed

    Tsuji, Takemasa; Matsuzaki, Junko; Caballero, Otavia L; Jungbluth, Achim A; Ritter, Gerd; Odunsi, Kunle; Old, Lloyd J; Gnjatic, Sacha

    2012-04-15

    Tumor Ag-specific CD4(+) T cells play important functions in tumor immunosurveillance, and in certain cases they can directly recognize HLA class II-expressing tumor cells. However, the underlying mechanism of intracellular Ag presentation to CD4(+) T cells by tumor cells has not yet been well characterized. We analyzed two naturally occurring human CD4(+) T cell lines specific for different peptides from cytosolic tumor Ag NY-ESO-1. Whereas both lines had the same HLA restriction and a similar ability to recognize exogenous NY-ESO-1 protein, only one CD4(+) T cell line recognized NY-ESO-1(+) HLA class II-expressing melanoma cells. Modulation of Ag processing in melanoma cells using specific molecular inhibitors and small interfering RNA revealed a previously undescribed peptide-selective Ag-presentation pathway by HLA class II(+) melanoma cells. The presentation required both proteasome and endosomal protease-dependent processing mechanisms, as well as cytosolic heat shock protein 90-mediated chaperoning. Such tumor-specific pathway of endogenous HLA class II Ag presentation is expected to play an important role in immunosurveillance or immunosuppression mediated by various subsets of CD4(+) T cells at the tumor local site. Furthermore, targeted activation of tumor-recognizing CD4(+) T cells by vaccination or adoptive transfer could be a suitable strategy for enhancing the efficacy of tumor immunotherapy.

  6. The Potential Role of Solvation in Antibody Recognition of the Lewis Y Antigen

    PubMed Central

    Saha, Somdutta; Murali, Ramachandran; Pashov, Anastas

    2015-01-01

    Solvents play an important role in protein folding, protein-protein associations, stability, and specificity of recognition as in the case of antibody-antigen interactions through hydrogen bonds. One of the underappreciated features of protein-associated waters is that it weakens inter- and intra-molecular interactions by modulating electrostatic interactions and influencing conformational changes. Such observations demonstrate the direct relationship between macroscopic solvent effects on protein-protein interactions and atom-scale solvent-protein interactions. Although crystallographic solvents do explain some aspects of solvent-mediated interactions, molecular simulation allows the study of the dynamic role of solvents. Thus, analysis of conformations from molecular simulations are employed to understand the role of solvent on the inherent polyspecificity of a Lewis Y reactive germline gene relative to its expanded hybridomas and a humanized anti-Lewis Y antibody. Our analysis reveals that solvent mediates critical contacts through charged residues to facilitate cross-reactivity to carbohydrate antigens, but also increases the flexibility of some anti-Lewis Y antibodies concomitant with mutations (amino acid substitutions) to the germline antibody. Such flexibility might better allow for recognition and binding of internal structures of extended carbohydrate structures on tumor cells. PMID:26492616

  7. Recognition of Microbial Glycolipids by Natural Killer T Cells

    PubMed Central

    Zajonc, Dirk M.; Girardi, Enrico

    2015-01-01

    T cells can recognize microbial antigens when presented by dedicated antigen-presenting molecules. While peptides are presented by classical members of the major histocompatibility complex (MHC) family (MHC I and II), lipids, glycolipids, and lipopeptides can be presented by the non-classical MHC member, CD1. The best studied subset of lipid-reactive T cells are type I natural killer T (iNKT) cells that recognize a variety of different antigens when presented by the non-classical MHCI homolog CD1d. iNKT cells have been shown to be important for the protection against various microbial pathogens, including B. burgdorferi, the causative agents of Lyme disease, and S. pneumoniae, which causes pneumococcal meningitis and community-acquired pneumonia. Both pathogens carry microbial glycolipids that can trigger the T cell antigen receptor (TCR), leading to iNKT cell activation. iNKT cells have an evolutionary conserved TCR alpha chain, yet retain the ability to recognize structurally diverse glycolipids. They do so using a conserved recognition mode, in which the TCR enforces a conserved binding orientation on CD1d. TCR binding is accompanied by structural changes within the TCR binding site of CD1d, as well as the glycolipid antigen itself. In addition to direct recognition of microbial antigens, iNKT cells can also be activated by a combination of cytokines (IL-12/IL-18) and TCR stimulation. Many microbes carry TLR antigens, and microbial infections can lead to TLR activation. The subsequent cytokine response in turn lower the threshold of TCR-mediated iNKT cell activation, especially when weak microbial or even self-antigens are presented during the cause of the infection. In summary, iNKT cells can be directly activated through TCR triggering of strong antigens, while cytokines produced by the innate immune response may be necessary for TCR triggering and iNKT cell activation in the presence of weak antigens. Here, we will review the molecular basis of iNKT cell

  8. Specific recognition of mycobacterial protein and peptide antigens by gamma-delta T cell subsets following infection with virulent Mycobacterium bovis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Promoting effective immunity to Mycobacterium tuberculosis complex pathogens is a challenge that is of interest to the fields of human and veterinary medicine alike. We report that gamma delta T cells from virulent Mycobacterium bovis-infected cattle respond specifically and directly to complex, pro...

  9. Antigenically Modified Human Pluripotent Stem Cells Generate Antigen-Presenting Dendritic Cells

    PubMed Central

    Zeng, Jieming; Wu, Chunxiao; Wang, Shu

    2015-01-01

    Human pluripotent stem cells (hPSCs) provide a promising platform to produce dendritic cell (DC) vaccine. To streamline the production process, we investigated a unique antigen-loading strategy that suits this novel platform. Specifically, we stably modified hPSCs using tumour antigen genes in the form of a full-length tumour antigen gene or an artificial tumour antigen epitope-coding minigene. Such antigenically modified hPSCs were able to differentiate into tumour antigen-presenting DCs. Without conventional antigen-loading, DCs derived from the minigene-modified hPSCs were ready to prime a tumour antigen-specific T cell response and further expand these specific T cells in restimulation processes. These expanded tumour antigen-specific T cells were potent effectors with central memory or effector memory phenotype. Thus, we demonstrated that immunocompetent tumour antigen-loaded DCs can be directly generated from antigenically modified hPSCs. Using such strategy, we can completely eliminate the conventional antigen-loading step and significantly simplify the production of DC vaccine from hPSCs. PMID:26471005

  10. Antigen Export Reduces Antigen Presentation and Limits T Cell Control of M. tuberculosis.

    PubMed

    Srivastava, Smita; Grace, Patricia S; Ernst, Joel D

    2016-01-13

    Persistence of Mycobacterium tuberculosis results from bacterial strategies that manipulate host adaptive immune responses. Infected dendritic cells (DCs) transport M. tuberculosis to local lymph nodes but activate CD4 T cells poorly, suggesting bacterial manipulation of antigen presentation. However, M. tuberculosis antigens are also exported from infected DCs and taken up and presented by uninfected DCs, possibly overcoming this blockade of antigen presentation by infected cells. Here we show that the first stage of this antigen transfer, antigen export, benefits M. tuberculosis by diverting bacterial proteins from the antigen presentation pathway. Kinesin-2 is required for antigen export and depletion of this microtubule-based motor increases activation of antigen-specific CD4 T cells by infected cells and improves control of intracellular infection. Thus, although antigen transfer enables presentation by bystander cells, it does not compensate for reduced antigen presentation by infected cells and represents a bacterial strategy for CD4 T cell evasion.

  11. Predicted complementarity determining regions of the T cell antigen receptor determine antigen specificity.

    PubMed Central

    Katayama, C D; Eidelman, F J; Duncan, A; Hooshmand, F; Hedrick, S M

    1995-01-01

    The antigen receptor on T cells (TCR) has been predicted to have a structure similar to a membrane-anchored form of an immunoglobulin F(ab) fragment. Virtually all of the conserved amino acids that are important for inter- and intramolecular interactions in the VH-VL pair are also conserved in the TCR V alpha and V beta chains. A molecular model of the TCR has been constructed by homology and we have used the information from this, as well as the earlier structural predictions of others, to study the basis for specificity. Specifically, regions of a TCR cloned from an antigen-specific T cell were stitched into the corresponding framework of a second TCR. Results indicate that the substitution of amino acid sequences corresponding to the complementarity determining regions (CDRs) of immunoglobulin can convey the specificity for antigen and major histocompatibility complex molecules. These data are consistent with a role, but not an exclusive role, for CDR3 in antigen peptide recognition. Images PMID:7534228

  12. Antigen Presentation by MHC-Dressed Cells

    PubMed Central

    Nakayama, Masafumi

    2015-01-01

    Professional antigen-presenting cells (APCs) such as conventional dendritic cells (DCs) process protein antigens to MHC-bound peptides and then present the peptide–MHC complexes to T cells. In addition to this canonical antigen presentation pathway, recent studies have revealed that DCs and non-APCs can acquire MHC class I (MHCI) and/or MHC class II (MHCII) from neighboring cells through a process of cell–cell contact-dependent membrane transfer called trogocytosis. These MHC-dressed cells subsequently activate or regulate T cells via the preformed antigen peptide–MHC complexes without requiring any further processing. In addition to trogocytosis, intercellular transfer of MHCI and MHCII can be mediated by secretion of membrane vesicles such as exosomes from APCs, generating MHC-dressed cells. This review focuses on the physiological role of antigen presentation by MHCI- or MHCII-dressed cells, and also discusses differences and similarities between trogocytosis and exosome-mediated transfer of MHC. PMID:25601867

  13. CD1 mediated T cell recognition of glycolipids.

    PubMed

    Zajonc, Dirk M; Kronenberg, Mitchell

    2007-10-01

    Specialized subsets of T lymphocytes can distinguish the carbohydrate portions of microbial and self-glycolipids when they are presented by proteins in the CD1 family of antigen presenting molecules. Recent immunochemical and structural analyses indicate that the chemical composition of the presented carbohydrate, together with its precise orientation above the CD1 binding groove, determines if a particular T cell is activated. More recently, however, it has been shown that the lipid backbone of the glycolipid, buried inside the CD1 protein, also can have an impact on T cell activation. While glycolipid recognition is a relatively new category of T cell specificity, the powerful combination of microbial antigen discovery and structural biochemistry has provided great insight into the mechanism of carbohydrate recognition.

  14. Recognition of mycobacterial antigens by sera from patients with leprosy.

    PubMed Central

    Vega-Lopez, F; Stoker, N G; Locniskar, M F; Dockrell, H M; Grant, K A; McAdam, K P

    1988-01-01

    Mycobacterium leprae sonic extracts prepared from armadillo-derived bacteria were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting (immunoblotting) procedures and probed with serum or plasma samples from 20 patients with lepromatous leprosy and 14 healthy endemic controls. Five proteins of 33, 25, 18, 15, and 12 kilodaltons (kDa) were frequently recognized; the 33- and 15-kDa proteins were, respectively, recognized with high intensity by 16 and 13 of the 20 samples from patients with leprosy, whereas only one healthy donor had antibodies that recognized the 15-kDa protein. By the use of M. leprae-specific murine monoclonal antibodies it was demonstrated that the 33-, 25-, and 15-kDa antigens were different from those bound by the available murine monoclonal antibodies. The 18- and 12-kDa proteins detected had molecular masses similar to those detected by the corresponding murine monoclonal antibodies. The serum and plasma samples from patients with leprosy were also used to probe Western blots of a soluble extract of M. tuberculosis. They recognized, among others, antigens with molecular weights similar to those detected in the M. leprae antigenic preparations, although with less intensity and at a lower frequency. Images PMID:3068245

  15. Carbohydrate specificity of the recognition of diverse glycolipids by natural killer T cells.

    PubMed

    Zajonc, Dirk M; Kronenberg, Mitchell

    2009-07-01

    Most T lymphocytes recognize peptide antigens bound to or presented by molecules encoded in the major histocompatibility complex (MHC). The CD1 family of antigen-presenting molecules is related to the MHC-encoded molecules, but CD1 proteins present lipid antigens, mostly glycolipids. Here we review T-lymphocyte recognition of glycolipids, with particular emphasis on the subpopulation known as natural killer T (NKT) cells. NKT cells influence many immune responses, they have a T-cell antigen receptor (TCR) that is restricted in diversity, and they share properties with cells of the innate immune system. NKT cells recognize antigens presented by CD1d with hexose sugars in alpha-linkage to lipids, although other, related antigens are known. The hydrophobic alkyl chains are buried in the CD1d groove, with the carbohydrate exposed for TCR recognition, together with the surface of the CD1d molecule. Therefore, understanding the biochemical basis for antigen recognition by NKT cells requires an understanding of how the trimolecular complex of CD1d, glycolipid, and the TCR is formed, which is in part a problem of carbohydrate recognition by the TCR. Recent investigations from our laboratories as well as studies from other groups have provided important information on the structural basis for NKT-cell specificity.

  16. Antibodies Raised Against Chlamydial Lipopolysaccharide Antigens Reveal Convergence in Germline Gene Usage and Differential Epitope Recognition

    PubMed Central

    Brooks, Cory L; Müller-Loennies, Sven; Borisova, Svetlana N.; Brade, Lore; Kosma, Paul; Hirama, Tomoko; MacKenzie, C. Roger; Brade, Helmut; Evans, Stephen V

    2011-01-01

    In order to explore monoclonal antibody recognition carbohydrate antigens, several structures from two monoclonal antibodies directed against carbohydrate epitopes derived from chlamydial LPS have been solved to high resolution. With the exception of CDR H3, antibodies S54-10 and S73-2 are both derived from the same set of germline gene segments as the previously reported structures S25-2 and S45-18. Despite this similarity, the antibodies differ in specificity and the mechanism by which they recognize their cognate antigen. S54-10 uses an unrelated CDR H3 to recognize its antigen in a fashion analogous to S45-18; however, S73-2 recognizes the same antigen as S45-18 and S54-10 in a wholly unrelated manner. Together, these antibody-antigen structures provide snapshots into how the immune system uses the same set of inherited germline gene segments to generate multiple possible specificities that allow for differential recognition of epitopes, and how unrelated CDR H3 sequences can result in convergent binding of clinically-relevant bacterial antigens. PMID:20000757

  17. Distinct antigen recognition pattern during zoonotic visceral leishmaniasis in humans and dogs.

    PubMed

    Goto, Yasuyuki; Howard, Randall F; Bhatia, Ajay; Trigo, Joelma; Nakatani, Maria; Netto, Eduardo M; Reed, Steven G

    2009-03-23

    Leishmania infantum is a causative agent of endemic zoonotic visceral leishmaniasis (VL) in regions of South America and the Mediterranean. Dogs are the major reservoirs for L. infantum in these regions, and control of disease in dogs could have a significant impact on human disease. Although dogs share many symptoms of VL with humans as a result of L. infantum infection, they also show some unique clinical manifestations, which are often a combination of visceral and cutaneous leishmaniasis, suggesting different mechanisms of disease development in dogs and humans. Here, we compare antibody responses of dogs and humans with VL to various defined leishmanial antigens. Parasite lysate and K39, the two most commonly used antigens for serodiagnosis of VL, detected the highest levels of antibodies in both humans and dogs with VL, whereas the recognition patterns of these antigens were distinct between the hosts. Among other defined antigens tested, LmSTI1 and CPB detected higher levels of antibodies in dogs and humans, respectively. These results indicate there is a difference between humans and dogs in antigen recognition patterns during VL. We infer that different strategies may need to be used in development of vaccines and diagnostics for humans and for dogs. In addition, we show a correlation between antibody titers to several antigens and severity of clinical symptoms during canine VL.

  18. Red cell antigens: Structure and function

    PubMed Central

    Pourazar, Abbasali

    2007-01-01

    Landsteiner and his colleagues demonstrated that human beings could be classified into four groups depending on the presence of one (A) or another (B) or both (AB) or none (O) of the antigens on their red cells. The number of the blood group antigens up to 1984 was 410. In the next 20 years, there were 16 systems with 144 antigens and quite a collection of antigens waiting to be assigned to systems, pending the discovery of new information about their relationship to the established systems. The importance of most blood group antigens had been recognized by immunological complications of blood transfusion or pregnancies; their molecular structure and function however remained undefined for many decades. Recent advances in molecular genetics and cellular biochemistry resulted in an abundance of new information in this field of research. In this review, we try to give some examples of advances made in the field of ‘structure and function of the red cell surface molecules.’ PMID:21938229

  19. Tumor escape mechanisms: Potential role of soluble HLA antigens and NK cells activating ligands

    PubMed Central

    Campoli, Michael; Ferrone, Soldano

    2009-01-01

    The crucial role played by HLA antigens and natural killer (NK) cell activating ligands in the interactions of malignant cells with components of the host's immune system has stimulated interest in the characterization of their expression by malignant cells. Convincing evidence generated by the immunohistochemical staining of surgically removed malignant lesions with monoclonal antibodies (mAb) recognizing HLA antigens and NK cell activating ligands indicates that the surface expression of these molecules is frequently altered on malignant cells. These changes appear to have clinical significance, since in some types of malignant disease they are associated with the histopathological characteristics of the lesions as well as with disease free interval and survival. These associations have been suggested to reflect the effect of HLA antigen and NK cell activating ligand abnormalities on the interactions of tumor cells with antigen-specific cytotoxic T lymphocytes (CTL) and with NK cells. Nevertheless, there are examples in which disease progresses in the face of appropriate HLA antigen and/or NK cell activating ligand as well as tumor antigen expression by malignant cells and of functional antigen-specific CTL in the investigated patient. In such scenarios, it is likely that the tumor microenvironment is unfavorable for CTL and NK cell activity and contributes to tumor immune escape. Many distinct escape mechanisms have been shown to protect malignant cells from immune recognition and destruction in the tumor microenvironment. In this paper, following the description of the structural and functional characteristics of soluble HLA antigens and NK cell activating ligands, we will review changes in their serum level in malignant disease and discuss their potential role in the escape mechanisms utilized by tumor cells to avoid recognition and destruction. PMID:18700879

  20. Stable isotope labeling of oligosaccharide cell surface antigens

    SciTech Connect

    Unkefer, C.J.; Silks, L.A. III; Martinez, R.A.

    1998-12-31

    The overall goal of this Laboratory Directed Research and Development (LDRD) project was to develop new methods for synthesis of {sup 13}C-labeled oligosaccharides that are required for nuclear magnetic resonance (NMR) studies of their solution conformation. Oligosaccharides are components of the cell`s outer surface and are involved in important processes such as cell-cell recognition and adhesion. Recently, Danishefsky and coworkers at Slone-Kettering Cancer Center developed a method for the solid-phase chemical synthesis of oligosaccharides. The specific goal of this LDRD project was to prepare uniform {sup 13}C-labeled aldohexose precursors required for the solid-phase synthesis of the Lewis blood-group antigenic determinants. We report the synthesis of {sup 13}C-labeled D-glucal, D-galactal and Fucosyl precursors. We have been collaborating with the Danishefsky group on the synthesis of the Lewis oligosaccharides and the NMR analysis of their solution conformation.

  1. Antigen affinity and antigen dose exert distinct influences on CD4 T-cell differentiation.

    PubMed

    Keck, Simone; Schmaler, Mathias; Ganter, Stefan; Wyss, Lena; Oberle, Susanne; Huseby, Eric S; Zehn, Dietmar; King, Carolyn G

    2014-10-14

    Cumulative T-cell receptor signal strength and ensuing T-cell responses are affected by both antigen affinity and antigen dose. Here we examined the distinct contributions of these parameters to CD4 T-cell differentiation during infection. We found that high antigen affinity positively correlates with T helper (Th)1 differentiation at both high and low doses of antigen. In contrast, follicular helper T cell (TFH) effectors are generated after priming with high, intermediate, and low affinity ligand. Unexpectedly, memory T cells generated after priming with very low affinity antigen remain impaired in their ability to generate secondary Th1 effectors, despite being recalled with high affinity antigen. These data challenge the view that only strongly stimulated CD4 T cells are capable of differentiating into the TFH and memory T-cell compartments and reveal that differential strength of stimulation during primary T-cell activation imprints unique and long lasting T-cell differentiation programs.

  2. T cell tolerance and activation to a transgene-encoded tumor antigen.

    PubMed

    Antoniou, A; McCormick, D; Scott, D; Yeoman, H; Chandler, P; Mellor, A; Dyson, J

    1996-05-01

    Much has been learned in recent years concerning the nature of tumor antigens recognized by T cells. To apply this knowledge clinically, the nature of the host response to individual and multiple tumor antigens has to be characterized. This will help to define the efficacy of immune surveillance and the immune status of the host following exposure to tumor antigens expressed on pre-neoplastic tissue. To approach these questions, we have developed a transgenic mouse which expresses the tumor-specific antigen P91A. The single amino acid substitution in P91A results in the expression of a new MHC class I (H-2Ld)-binding peptide. In transgenic tissue, the H-2Ld/P91A complex is expressed in isolation from other tumor-associated antigens, allowing definition of the immune response to a single defined tumor antigen, a situation closely analogous to events during tumorigenesis. We show that CD8+ T cell immune surveillance of P91A is ineffective without the introduction of a helper determinant operating through stimulation of CD4+ T cells. Recognition of the isolated P91A tumor antigen on normal tissue by CD8+ T cells is a tolerogenic process. Induction of T cell tolerance suggests tumor antigen-T cell interactions occurring during tumorigenesis may elicit T cell tolerance and hence confound some immunotherapeutic approaches.

  3. Diverse Endogenous Antigens for Mouse Natural Killer T Cells: Self-Antigens That Are Not Glycosphingolipids

    PubMed Central

    Pei, Bo; Speak, Anneliese O; Shepherd, Dawn; Butters, Terry; Cerundolo, Vincenzo; Platt, Frances M; Kronenberg, Mitchell

    2011-01-01

    Natural killer T cells with an invariant antigen receptor (iNKT cells) represent a highly conserved and unique subset of T lymphocytes having properties of innate and adaptive immune cells. They have been reported to regulate a variety of immune responses, including the response to cancers and the development of autoimmunity. The development and activation of iNKT cells is dependent on self-antigens presented by the CD1d antigen-presenting molecule. It is widely believed that these self-antigens are glycosphingolipids (GSLs), molecules that contain ceramide as the lipid backbone. Here we used a variety of methods to show that mammalian antigens for mouse iNKT cells need not be GSLs, including the use of cell lines deficient in GSL biosynthesis and an inhibitor of GSL biosynthesis. Presentation of these antigens required the expression of CD1d molecules that could traffic to late endosomes, the site where self-antigen is acquired. Extracts of antigen-presenting cells (APCs) contain a self-antigen that could stimulate iNKT cells when added to plates coated with soluble, recombinant CD1d molecules. The antigen(s) in these extracts are resistant to sphingolipid-specific hydrolase digestion, consistent with the results using live APCs. Lyosphosphatidylcholine, a potential self-antigen that activated human iNKT cell lines, did not activate mouse iNKT cell hybridomas. Our data indicate that there may be more than one type of self-antigen for iNKT cells, that the self-antigens comparing mouse and human may not be conserved, and that the search to identify these molecules should not be confined to GSLs. PMID:21191069

  4. Viral cell recognition and entry.

    PubMed Central

    Rossmann, M. G.

    1994-01-01

    Rhinovirus infection is initiated by the recognition of a specific cell-surface receptor. The major group of rhinovirus serotypes attach to intercellular adhesion molecule-1 (ICAM-1). The attachment process initiates a series of conformational changes resulting in the loss of genomic RNA from the virion. X-ray crystallography and sequence comparisons suggested that a deep crevice or canyon is the site on the virus recognized by the cellular receptor molecule. This has now been verified by electron microscopy of human rhinovirus 14 (HRV14) and HRV16 complexed with a soluble component of ICAM-1. A hydrophobic pocket underneath the canyon is the site of binding of various hydrophobic drug compounds that can inhibit attachment and uncoating. This pocket is also associated with an unidentified, possibly cellular in origin, "pocket factor." The pocket factor binding site overlaps the binding site of the receptor. It is suggested that competition between the pocket factor and receptor regulates the conformational changes required for the initiation of the entry of the genomic RNA into the cell. PMID:7849588

  5. Antigen-Presenting Cells and Antigen Presentation in Tertiary Lymphoid Organs

    PubMed Central

    Hughes, Catherine E.; Benson, Robert A.; Bedaj, Marija; Maffia, Pasquale

    2016-01-01

    Tertiary lymphoid organs (TLOs) form in territorialized niches of peripheral tissues characterized by the presence of antigens; however, little is known about mechanism(s) of antigen handling by ectopic lymphoid structures. In this mini review, we will discuss the role of antigen-presenting cells and mechanisms of antigen presentation in TLOs, summarizing what is currently known about this facet of the formation and function of these tissues as well as identifying questions yet to be addressed. PMID:27872626

  6. Isolation and In vivo Transfer of Antigen Presenting Cells

    PubMed Central

    Arora, Pooja; Kharkwal, Shalu Sharma; Porcelli, Steven A.

    2016-01-01

    Transfer of antigen presenting cells in vivo is a method used by immunologists to examine the potency of antigen presentation by a selected population of cells. This method is most commonly used to analyze presentation of protein antigens to MHC class I or II restricted T cells, but it can also be used for studies of nonconventional antigens such as CD1-presented lipids. In a recent study focusing on CD1d-restricted glycolipid antigen presentation to Natural Killer T cells, we compared antigen presenting properties of splenic B cells, CD8αPos dendritc cells (DCs) and CD8αNeg DCs (Arora et al., 2014). This protocol describes the detailed method used for isolation of these cell populations, and their transfer into recipient mice to analyze their antigen presenting properties. PMID:27390759

  7. Deconstructing the peptide-MHC specificity of T cell recognition

    PubMed Central

    Birnbaum, Michael E.; Mendoza, Juan L.; Sethi, Dhruv K.; Dong, Shen; Glanville, Jacob; Dobbins, Jessica; Özkan, Engin; Davis, Mark M.; Wucherpfennig, Kai W.; Garcia, K. Christopher

    2014-01-01

    Summary In order to survey a universe of MHC-presented peptide antigens whose numbers greatly exceed the diversity of the T cell repertoire, T cell receptors (TCRs) are thought to be cross-reactive. However, the nature and extent of TCR cross-reactivity has not been conclusively measured experimentally. We developed a system to identify MHC-presented peptide ligands by combining TCR selection of highly diverse yeast-displayed peptide-MHC libraries with deep sequencing. While we identified hundreds of peptides reactive with each of five different mouse and human TCRs, the selected peptides possessed TCR recognition motifs that bore a close resemblance to their known antigens. This structural conservation of the TCR interaction surface allowed us to exploit deep sequencing information to computationally identify activating microbial and self-ligands for human autoimmune TCRs. The mechanistic basis of TCR cross-reactivity described here enables effective surveillance of diverse self and foreign antigens, but without necessitating degenerate recognition of non-homologous peptides. PMID:24855945

  8. Unidirectional transfer of microRNA-loaded exosomes from T cells to antigen-presenting cells

    PubMed Central

    Mittelbrunn, María; Gutiérrez-Vázquez, Cristina; Villarroya-Beltri, Carolina; González, Susana; Sánchez-Cabo, Fátima; González, Manuel Ángel; Bernad, Antonio; Sánchez-Madrid, Francisco

    2011-01-01

    The immune synapse is an exquisitely evolved means of communication between T cells and antigen-presenting cells (APCs) during antigen recognition. Recent evidence points to the transfer of RNA via exosomes as a novel mode of intercellular communication. Here we show that exosomes of T, B and dendritic immune cells contain microRNA (miRNA) repertoires that differ from those of their parent cells. We investigate whether miRNAs are exchanged during cognate immune interactions, and demonstrate the existence of antigen-driven unidirectional transfer of miRNAs from the T cell to the APC, mediated by the delivery of CD63+ exosomes on immune synapse formation. Inhibition of exosome production by targeting neutral sphingomyelinase-2 impairs transfer of miRNAs to APCs. Moreover, miRNAs transferred during immune synapsis are able to modulate gene expression in recipient cells. Thus, our results support a mechanism of cellular communication involving antigen-dependent, unidirectional intercellular transfer of miRNAs by exosomes during immune synapsis. PMID:21505438

  9. Blood Group Antigen Recognition via the Group A Streptococcal M Protein Mediates Host Colonization

    PubMed Central

    De Oliveira, David M. P.; Hartley-Tassell, Lauren; Everest-Dass, Arun; Day, Christopher J.; Dabbs, Rebecca A.; Ve, Thomas; Kobe, Bostjan; Nizet, Victor; Packer, Nicolle H.; Walker, Mark J.; Jennings, Michael P.

    2017-01-01

    ABSTRACT Streptococcus pyogenes (group A streptococcus [GAS]) is responsible for over 500,000 deaths worldwide each year. The highly virulent M1T1 GAS clone is one of the most frequently isolated serotypes from streptococcal pharyngitis and invasive disease. The oral epithelial tract is a niche highly abundant in glycosylated structures, particularly those of the ABO(H) blood group antigen family. Using a high-throughput approach, we determined that a strain representative of the globally disseminated M1T1 GAS clone 5448 interacts with numerous, structurally diverse glycans. Preeminent among GAS virulence factors is the surface-expressed M protein. M1 protein showed high affinity for several terminal galactose blood group antigen structures. Deletion mutagenesis shows that M1 protein mediates glycan binding via its B repeat domains. Association of M1T1 GAS with oral epithelial cells varied significantly as a result of phenotypic differences in blood group antigen expression, with significantly higher adherence to those cells expressing H antigen structures compared to cells expressing A, B, or AB antigen structures. These data suggest a novel mechanism for GAS attachment to host cells and propose a link between host blood group antigen expression and M1T1 GAS colonization. PMID:28119471

  10. Direct activation of antigen-presenting cells is required for CD8+ T-cell priming and tumor vaccination

    PubMed Central

    Kratky, Wolfgang; Reis e Sousa, Caetano; Oxenius, Annette; Spörri, Roman

    2011-01-01

    Successful priming of adaptive immune responses is crucially dependent on innate activation signals that convert resting antigen-presenting cells (APCs) into immunogenic ones. APCs expressing the relevant innate pattern recognition receptors can be directly activated by pathogen-associated molecular patterns (PAMPs) to become competent to prime T-cell responses. Alternatively, it has been suggested that APCs could be activated indirectly by proinflammatory mediators synthesized by PAMP-exposed cells. However, data obtained with CD4+ T cells suggest that inflammatory signals often cannot substitute for direct pattern recognition in APC activation for the priming of T helper responses. To test whether the same is true for CD8+ T cells, we studied cytotoxic T lymphocyte development in vitro and in mixed chimeric mice in which coexisting APCs can either present a preprocessed model antigen or directly recognize a given PAMP, but not both. We show that indirectly activated APCs promote antigen-specific proliferation of naïve CD8+ T cells but fail to support their survival and cytotoxic T lymphocyte differentiation. Furthermore, CD8+ T cells primed by indirectly activated APCs are unable to reject tumors. Thus, inflammation cannot substitute for direct recognition of single PAMPs in CD8+ T-cell priming. These findings have important practical implications for vaccine design, indicating that adjuvants must be judiciously chosen to trigger the relevant pattern recognition receptors in APCs. PMID:21987815

  11. Antigen-Presenting Cells in the Skin.

    PubMed

    Kashem, Sakeen W; Haniffa, Muzlifah; Kaplan, Daniel H

    2017-02-06

    Professional antigen-presenting cells (APCs) in the skin include dendritic cells, monocytes, and macrophages. They are highly dynamic, with the capacity to enter skin from the peripheral circulation, patrol within tissue, and migrate through lymphatics to draining lymph nodes. Skin APCs are endowed with antigen sensing, processing, and presenting machinery and play key roles in initiating, modulating, and resolving cutaneous inflammation. Skin APCs are a highly heterogeneous population with functionally specialized subsets that are developmentally imprinted and modulated by local tissue microenvironmental and inflammatory cues. This review explores recent advances that have allowed for a more accurate taxonomy of APC subsets found in both mouse and human skin. It also examines the functional specificity of individual APC subsets and their collaboration with other immune cell types that together promote adaptive T cell and regional cutaneous immune responses during homeostasis, inflammation, and disease. Expected final online publication date for the Annual Review of Immunology Volume 35 is April 26, 2017 . Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  12. A human T cell clone that mediates the monocyte procoagulant response to specific sensitizing antigen.

    PubMed

    Schwartz, B S; Reitnauer, P J; Hank, J A; Sondel, P M

    1985-09-01

    A panel of human purified protein derivative of the tubercle bacillus (PPD)-reactive T cell clones was derived by cloning out of soft agar followed by cultivation on inactivated feeder cells in the presence of interleukin-2. 1 of 4 clones tested was able to mediate an increase in monocyte procoagulant activity (PCA) in response to PPD. All four clones had identical surface marker phenotypes (T4+, T8-) and proliferated in response to antigen. The reactive T cell clone possessed no PCA of its own, but upon being presented with PPD was able to instruct monocytes to increase their expression of PCA. Antigen presentation could be performed only by autologous monocytes; allogeneic monocytes from donors unrelated to the donor of the reactive clone could not present antigen to cells of the clone in a way that would initiate the procoagulant response. Cells of the reactive clone did not mediate increased monocyte PCA in response to Candida, even though peripheral blood mononuclear cells from the donor demonstrated increased PCA to both Candida and PPD. Thus, the PCA response to specific antigen can be mediated by a single clone of cells that shows specificity in the recognition of both antigen and antigen presenting cell.

  13. A possible model for cell-cell recognition via surface macromolecules.

    PubMed

    Burger, M M; Turner, R S; Kuhns, W J; Weinbaum, G

    1975-07-17

    Alternative possibilities for the establishment of the proper cell distribution during embryogenesis are summarized at the beginning, followed by an assessment of the examples known so far where cell-cell recognition is known to be mediated via cell surface components. In the second part the species-specific recognition process which occurs during the sorting-out of dissociated sponge cells is analysed since it may serve as a possible model for cell-cell recognition in higher animals. Three possible mechanisms for the establishment of proper cell distribution are considered. These include, first, chemotaxis: secondly, guidance of cell or cell sheet movement by extracellular matrix or by surrounding cells and thirdly, random movement followed by recognition at the final point of destination. Recognition is necessary for both of the two latter processes, i.e. for cell guidance as well as for locking the cells into their final position after random movement. Two basically different recognition mechanisms should be distinguished from each other. On the one hand cells may recognize each other with the help of macromolecules situated in or just outside of the plasmamembrane which fit to each other like enzymes and substrates or antibodies and antigens. On the other hand, cells may exchange information by exchanging cytoplasmatic components via vesicles or gap junctions. The species-specific aggregation of dissociated sponge cells is considered to be a possible model for cell-cell recognition in higher animals. A proteoglycan-like intercellular macromolecule called aggregation factor seems to mediate recognition of a given species of cells in the reaggregation process of dissociated cells. The data available at the present time suggest that a monovalent surface macromolecule (baseplate) may mediate the recognition process probably by recognizing the carbohydrate side chains of the multivalent proteoglycan aggregation factor. A cell-free system was devised to mimic this

  14. LOCALIZATION OF ANTIGEN IN TISSUE CELLS

    PubMed Central

    Coons, Albert H.; Leduc, Elizabeth H.; Kaplan, Melvin H.

    1951-01-01

    The fate of three proteins, crystalline hen's egg albumin, crystalline bovine plasma albumin, and human plasma γ-globulin, was traced after intravenous injection into mice. This was done by preparing frozen sections of quick-frozen tissue, allowing what foreign protein might be present in the section to react with homologous antibody labelled with fluorescein, and examining the section under the fluorescence microscope. By this means, which employs the serological specificity of the protein as a natural "marker," all three of these proteins were found in the cells of the reticulo-endothelial system, the connective tissue, the vascular endothelium, the lymphocytes of spleen and lymph node, and the epithelium of the kidney tubules, the liver, and in very small amounts in the adrenal. The central nervous system was not studied. All three persisted longest in the reticulo-endothelial system and the connective tissue, and in the doses employed egg white (10 mg.) was no longer detectable after 1 day, bovine albumin (10 mg.) after 2 days, and human γ-globulin (4 mg.) after 6 days, although in a somewhat higher dose (10 mg.) human γ-globulin persisted longer than 8 days. Egg albumin differed from the others in not being detectable in the cells of the renal glomerulus. It was found that each of the three proteins was present in the nuclei of each cell type enumerated above, often in higher concentration than in the cytoplasm. Further, some of the nuclei not only contained antigen, soon after injection, but were also surrounded by a bright ring associated with the nuclear membrane. By means of photographic records under the fluorescence microscope of sections stained for antigen, and direct observation under the light microscope of the same field subsequently stained with hematoxylin and eosin, it could be determined that the antigen was not adsorbed to chromatin or nucleoli, but was apparently in solution in the nuclear sap. PMID:14803641

  15. Regulation of NK-cell function by mucins via antigen-presenting cells.

    PubMed

    Laskarin, G; Redzovic, A; Medancic, S Srsen; Rukavina, D

    2010-12-01

    Decidual antigen-presenting cells including dendritic cells (DCs) and CD14(+) macrophages, as mediators of the first encounter with fetal antigens, appear to be critically involved in the initiation of primary immune response by regulating innate- and adaptive immunity. Interleukin-15, produced by them, permits the proliferation and differentiation of CD3(-)CD16(-)CD94(+)NKG2A(+)CD56(+bright) decidual NK cells that identify trophoblast cells. These cells are able to kill them after Th1 cytokine overstimulation and by increasing the release of preformed cytotoxic mediators. Thus, the local microenvironment is a potent modulator of antigen-presenting cell functions. Tumor associated glycoprotein-72 (TAG-72) and mucine 1 (MUC-1) are glycoproteins secreted by uterine epithelial cells. Our hypothesis is that TAG-72 and MUC-1 are the natural ligands for carbohydrate recognition domains (CRDs) of endocytic mannose receptor (MR or CD206) and DC-specific ICAM non-integrin (DC-SIGN or CD209) expressed on decidual CD14(+) macrophages and CD1a(+) DCs. They might be able to condition antigen-presenting cells to produce distinct profiles of cyto/chemokines with consequential reduction in NK-cell numbers and cytotoxic potential leading to insufficient control over trophoblast growth. This hypothesis could explain the disappearance of MUC-1 beneath the attached embryo during the process of successful implantation when tight regulation of trophoblast invasion is needed. As IL-15 is the earliest and the most important factor in NK-cell proliferation, differentiation, and maturation, we expected primarily an increase of IL-15 expression in antigen-presenting cells concomitant with the disappearance of mucins and the enhancement in NK cells numbers and of cytotoxic potential after their close contact with early pregnancy decidual antigen-presenting cells. If our hypothesis is correct, it would contribute to the understanding of the role of mucins in the redirection of immune response

  16. T Helper Cell Tolerance to Ubiquitous Nuclear Antigens

    PubMed Central

    NAKKEN, BRITT; DAVIS, KAREN E.; PAN, ZIJIAN; BACHMANN, MICHAEL; FARRIS, A. DARISE

    2007-01-01

    Systemic autoimmune diseases are characterized by the development of anti-nuclear autoantibodies. In order to understand the immunologic events leading to the development of such antibodies, knowledge of mechanisms of immune tolerance to nuclear antigens is required. By utilizing adoptive T cell transfer strategies with transgenic mouse models expressing nuclear neo-self antigens, T cell tolerance to the lupus-related nuclear antigens human La and nRNP A has been demonstrated. These findings also indicate the existence in normal animals of autoreactive B cells continuously presenting nuclear antigen, suggesting that nuclear antigens are not sequestered from the immune system. Investigations of CD4+ T cell tolerance to non-nuclear antigens have revealed a number of mechanisms that protect the host from autoreactivity, including autoreactive T cell deletion, regulatory T cell development and anergy induction. Recent studies using T cell receptor and neo-self nuclear antigen transgenic mice are revealing the importance of such mechanisms in maintaining tolerance to nuclear antigens. Mechanisms of tolerogenic antigen presentation, identification of tolerogenic antigen source(s), and the pathways leading to loss of tolerance to nuclear antigens in systemic autoimmune disease states are currently being sought. PMID:14629620

  17. T-cell responses to minor histocompatibility antigens.

    PubMed Central

    Lai, P K; Waterfield, J D; Gascoigne, N R; Sharrock, C E; Mitchison, N A

    1982-01-01

    We have investigated the helper and cytotoxic T-cell response to minor histocompatibility antigens and generated long term antigen-specific cell lines to them. Antigen-specific activity was selected for by regular restimulation with irradiated cells bearing the antigens in the presence of interleukin 2, so that alloreactivity to other cell surface antigens was gradually lost. Helper T cells cultured over several months were active in vivo and in vitro, but the culturing method eventually selected for cytotoxic T cells at the expense of helper T cells, with concomitant changes in the proportions of cells expressing the Lyt phenotypes. Individual long term cultures of cytotoxic T cells specific for minor histocompatibility antigens were restricted by either H2K or D but not both. Helper T cells to minor histocompatibility antigens derived directly from primed F1 mice did not show restriction to the priming parental haplotype. This is consistent with antigen reprocessing by the F1 antigen presenting cells such that populations of helper T cells restricted by both parental H-2 haplotypes were primed. F1 cytotoxic T cells were restricted to the parental H-2 haplotype used for in vitro boosting, irrespective of which H-2 was used for in vivo priming. PMID:6214502

  18. Proliferating cell nuclear antigen: a proteomics view.

    PubMed

    Naryzhny, S N

    2008-11-01

    Proliferating cell nuclear antigen (PCNA), a cell cycle marker protein, is well known as a DNA sliding clamp for DNA polymerase delta and as an essential component for eukaryotic chromosomal DNA replication and repair. Due to its mobility inside nuclei, PCNA is dynamically presented in a soluble or chromatin-associated form. The heterogeneity and specific modifications of PCNA may reflect its multiple functions and the presence of many binding partners in the cell. The recent proteomics approaches applied to characterizing PCNA interactions revealed multiple PCNA partners with a wide spectrum of activity and unveiled the possible existence of new PCNA functions. Since more than 100 PCNA-interacting proteins and several PCNA modifications have already been reported, a proteomics point of view seems exactly suitable to better understand the role of PCNA in cellular functions.

  19. Antigen presentation for priming T cells in central system.

    PubMed

    Dasgupta, Shaoni; Dasgupta, Subhajit

    2017-01-01

    Generation of myelin antigen-specific T cells is a major event in neuroimmune responses that causes demyelination. The antigen-priming of T cells and its location is important in chronic and acute inflammation. In autoimmune multiple sclerosis, the effector T cells are considered to generate in periphery. However, the reasons for chronic relapsing-remitting events are obscure. Considering mechanisms, a feasible aim of research is to investigate the role of antigen-primed T cells in lupus cerebritis. Last thirty years of investigations emphasize the relevance of microglia and infiltrated dendritic cells/macrophages as antigen presenting cells in the central nervous system. The recent approach towards circulating B-lymphocytes is an important area in the context. Here, we analyze the existing findings on antigen presentation in the central nervous system. The aim is to visualize signaling events of myelin antigen presentation to T cells and lead to the strategy of future goals on immunotherapy research.

  20. Viral Escape Mutant Epitope Maintains TCR Affinity for Antigen yet Curtails CD8 T Cell Responses.

    PubMed

    Shorter, Shayla K; Schnell, Frederick J; McMaster, Sean R; Pinelli, David F; Andargachew, Rakieb; Evavold, Brian D

    2016-01-01

    T cells have the remarkable ability to recognize antigen with great specificity and in turn mount an appropriate and robust immune response. Critical to this process is the initial T cell antigen recognition and subsequent signal transduction events. This antigen recognition can be modulated at the site of TCR interaction with peptide:major histocompatibility (pMHC) or peptide interaction with the MHC molecule. Both events could have a range of effects on T cell fate. Though responses to antigens that bind sub-optimally to TCR, known as altered peptide ligands (APL), have been studied extensively, the impact of disrupting antigen binding to MHC has been highlighted to a lesser extent and is usually considered to result in complete loss of epitope recognition. Here we present a model of viral evasion from CD8 T cell immuno-surveillance by a lymphocytic choriomeningitis virus (LCMV) escape mutant with an epitope for which TCR affinity for pMHC remains high but where the antigenic peptide binds sub optimally to MHC. Despite high TCR affinity for variant epitope, levels of interferon regulatory factor-4 (IRF4) are not sustained in response to the variant indicating differences in perceived TCR signal strength. The CD8+ T cell response to the variant epitope is characterized by early proliferation and up-regulation of activation markers. Interestingly, this response is not maintained and is characterized by a lack in IL-2 and IFNγ production, increased apoptosis and an abrogated glycolytic response. We show that disrupting the stability of peptide in MHC can effectively disrupt TCR signal strength despite unchanged affinity for TCR and can significantly impact the CD8+ T cell response to a viral escape mutant.

  1. Viral Escape Mutant Epitope Maintains TCR Affinity for Antigen yet Curtails CD8 T Cell Responses

    PubMed Central

    Shorter, Shayla K.; Schnell, Frederick J.; McMaster, Sean R.; Pinelli, David F.; Andargachew, Rakieb; Evavold, Brian D.

    2016-01-01

    T cells have the remarkable ability to recognize antigen with great specificity and in turn mount an appropriate and robust immune response. Critical to this process is the initial T cell antigen recognition and subsequent signal transduction events. This antigen recognition can be modulated at the site of TCR interaction with peptide:major histocompatibility (pMHC) or peptide interaction with the MHC molecule. Both events could have a range of effects on T cell fate. Though responses to antigens that bind sub-optimally to TCR, known as altered peptide ligands (APL), have been studied extensively, the impact of disrupting antigen binding to MHC has been highlighted to a lesser extent and is usually considered to result in complete loss of epitope recognition. Here we present a model of viral evasion from CD8 T cell immuno-surveillance by a lymphocytic choriomeningitis virus (LCMV) escape mutant with an epitope for which TCR affinity for pMHC remains high but where the antigenic peptide binds sub optimally to MHC. Despite high TCR affinity for variant epitope, levels of interferon regulatory factor-4 (IRF4) are not sustained in response to the variant indicating differences in perceived TCR signal strength. The CD8+ T cell response to the variant epitope is characterized by early proliferation and up-regulation of activation markers. Interestingly, this response is not maintained and is characterized by a lack in IL-2 and IFNγ production, increased apoptosis and an abrogated glycolytic response. We show that disrupting the stability of peptide in MHC can effectively disrupt TCR signal strength despite unchanged affinity for TCR and can significantly impact the CD8+ T cell response to a viral escape mutant. PMID:26915099

  2. Murine cell-mediated immune response recognizes an enterovirus group-specific antigen(s).

    PubMed Central

    Beck, M A; Tracy, S M

    1989-01-01

    Splenocytes taken from mice inoculated with coxsackievirus B3 (CVB3) (Nancy) developed an in vitro proliferative response against CVB3 antigen. This response could not be detected earlier than 8 days postinoculation but could be detected up to 28 days after exposure to CB3. CVB3-sensitized splenocytes responded not only to the CVB3 antigen but to other enteroviruses as well. This response was found to be enterovirus specific in that no response was detected to a non-enteroviral picornavirus, encephalomyocarditis virus, or to an unrelated influenza virus. The generation of a splenocyte population capable of responding to an enterovirus group antigen(s) was not limited to inoculation of mice with CVB3, as similar responses were generated when mice were inoculated with CVB2. Cell subset depletions revealed that the major cell type responding to the enterovirus group antigen(s) was the CD4+ T cell. Current evidence suggests that the group antigen(s) resides in the structural proteins of the virus, since spleen cells from mice inoculated with a UV-inactivated, highly purified preparation of CVB3 virions also responded in vitro against enteroviral antigens. PMID:2476566

  3. Molecular Characterization of a Fully Human Chimeric T-Cell Antigen Receptor for Tumor-Associated Antigen EpCAM

    PubMed Central

    Shirasu, Naoto; Yamada, Hiromi; Shibaguchi, Hirotomo; Kuroki, Motomu; Kuroki, Masahide

    2012-01-01

    The transduction of T cells to express chimeric T-cell antigen receptor (CAR) is an attractive strategy for adaptive immunotherapy for cancer, because the CAR can redirect the recognition specificity of T cells to tumor-associated antigens (TAAs) on the surface of target cells, thereby avoiding the limitations of HLA restriction. However, there are considerable problems with the clinical application of CAR, mostly due to its xenogeneic components, which could be immunogenic in humans. Moreover, while extensive studies on the CARs have been performed, the detailed molecular mechanisms underlying the activation of CAR-grafted T cells remain unclear. In order to eliminate potential immunogenicity and investigate the molecular basis of the CAR-mediated T-cell activation, we constructed a novel CAR (CAR57-28ζ) specific for one of the most important TAAs, epithelial cell adhesion molecule (EpCAM), using only human-derived genes. We revealed that in Jurkat T cells, lentivirally expressed CAR57-28ζ can transmit the T-cell-activating signals sufficient to induce IL-2 production upon EpCAM stimulation. An immunofluorescent analysis clearly showed that the CAR57-28ζ induces the formation of signaling clusters containing endogenous CD3ζ at the CAR/EpCAM interaction interface. These results suggest that this CAR gene may be safely and effectively applied for adaptive T-cell immunotherapy. PMID:22547929

  4. Two genetically identical antigen-presenting cell clones display heterogeneity in antigen processing.

    PubMed Central

    Michalek, M T; Benacerraf, B; Rock, K L

    1989-01-01

    Evidence from various antigen systems suggests that antigen processing can be one factor that determines the repertoire of immunogenic peptides. Thus, processing events may account for some of the disparity between the available and expressed helper T-cell repertoires. In this report, we demonstrate that the immunodominant T-cell determinant in ovalbumin [p323-339; ovalbumin-(323-339) heptadecapeptide] is processed differently by two genetically identical antigen-presenting cell lines, M12 and A20. The ovalbumin-specific T-cell-T-cell hybridomas, DO-11.10 and 3DO-54.8, were used to detect processed antigen. These T-T hybridomas have different fine specificities for the p323-339 determinant. A20 cells presented native ovalbumin well to both T-T hybridomas, whereas M12 cells presented native ovalbumin well to 3DO-54.8 but very inefficiently to DO-11.10. M12 and A20 cells effectively stimulated both T-T hybridomas with the same concentrations of the immunogenic synthetic peptide p323-339. Therefore, M12 cells and DO-11.10 can interact with each other, and both T-T hybridomas have similar sensitivities for the same immunogenic peptide. We conclude that genetically identical antigen-presenting cells can display heterogeneity in the fine processing of an immunodominant T-cell determinant, and synthetic model peptides that represent the minimal stimulatory sequence of a T-cell determinant are not necessarily identical to the structure of in vivo processed antigen. Heterogeneity in antigen processing by individual antigen-presenting cells would serve to increase the repertoire of immunogenic peptides that are presented to T cells. PMID:2470101

  5. Innate-like recognition of microbes by invariant natural killer T cells.

    PubMed

    Kronenberg, Mitchell; Kinjo, Yuki

    2009-08-01

    Invariant natural killer T cells (iNKT cells) express a restricted T cell antigen receptor (TCR) repertoire and they respond rapidly to glycolipid antigens presented by CD1d. These glycolipid antigens have hexose sugars in alpha-linkage to two types of lipids that can bind to CD1d. Recent work has shown that the responses of iNKT cells to antigen-bearing microbes can have a profound impact on the development of inflammatory diseases. iNKT cells overcome the limitation of their limited TCR diversity by also responding in a foreign antigen-independent fashion to some infectious agents, similar to NK cells. Recent results demonstrate several mechanisms for the indirect activation of iNKT cells by viruses or TLR ligands, dependent on self-antigen recognition and/or different cytokines produced by antigen presenting cells. The means by which iNKT cells influence other cell types and overall host defense are likewise diverse, illustrating the flexibility and functional diversity of this T lymphocyte sublineage.

  6. Targeted delivery of antigen to hamster nasal lymphoid tissue with M-cell-directed lectins.

    PubMed Central

    Giannasca, P J; Boden, J A; Monath, T P

    1997-01-01

    The nasal cavity of a rodent is lined by an epithelium organized into distinct regional domains responsible for specific physiological functions. Aggregates of nasal lymphoid tissue (NALT) located at the base of the nasal cavity are believed to be sites of induction of mucosal immune responses to airborne antigens. The epithelium overlying NALT contains M cells which are specialized for the transcytosis of immunogens, as demonstrated in other mucosal tissues. We hypothesized that NALT M cells are characterized by distinct glycoconjugate receptors which influence antigen uptake and immune responses to transcytosed antigens. To identify glycoconjugates that may distinguish NALT M cells from other cells of the respiratory epithelium (RE), we performed lectin histochemistry on sections of the hamster nasal cavity with a panel of lectins. Many classes of glycoconjugates were found on epithelial cells in this region. While most lectins bound to sites on both the RE and M cells, probes capable of recognizing alpha-linked galactose were found to label the follicle-associated epithelium (FAE) almost exclusively. By morphological criteria, the FAE contains >90% M cells. To determine if apical glycoconjugates on M cells were accessible from the nasal cavity, an M-cell-selective lectin and a control lectin in parallel were administered intranasally to hamsters. The M-cell-selective lectin was found to specifically target the FAE, while the control lectin did not. Lectin bound to M cells in vivo was efficiently endocytosed, consistent with the role of M cells in antigen transport. Intranasal immunization with lectin-test antigen conjugates without adjuvant stimulated induction of specific serum immunoglobulin G, whereas antigen alone or admixed with lectin did not. The selective recognition of NALT M cells by a lectin in vivo provides a model for microbial adhesin-host cell receptor interactions on M cells and the targeted delivery of immunogens to NALT following intranasal

  7. Chimeric Antigen Receptor-Engineered T Cells for Immunotherapy of Cancer

    PubMed Central

    Cartellieri, Marc; Bachmann, Michael; Feldmann, Anja; Bippes, Claudia; Stamova, Slava; Wehner, Rebekka; Temme, Achim; Schmitz, Marc

    2010-01-01

    CD4+ and CD8+ T lymphocytes are powerful components of adaptive immunity, which essentially contribute to the elimination of tumors. Due to their cytotoxic capacity, T cells emerged as attractive candidates for specific immunotherapy of cancer. A promising approach is the genetic modification of T cells with chimeric antigen receptors (CARs). First generation CARs consist of a binding moiety specifically recognizing a tumor cell surface antigen and a lymphocyte activating signaling chain. The CAR-mediated recognition induces cytokine production and tumor-directed cytotoxicity of T cells. Second and third generation CARs include signal sequences from various costimulatory molecules resulting in enhanced T-cell persistence and sustained antitumor reaction. Clinical trials revealed that the adoptive transfer of T cells engineered with first generation CARs represents a feasible concept for the induction of clinical responses in some tumor patients. However, further improvement is required, which may be achieved by second or third generation CAR-engrafted T cells. PMID:20467460

  8. Recognition Strategies of Group 3 Innate Lymphoid Cells

    PubMed Central

    Killig, Monica; Glatzer, Timor; Romagnani, Chiara

    2014-01-01

    During the early phase of an inflammatory response, innate cells can use different strategies to sense environmental danger. These include the direct interaction of specific activating receptors with pathogen-encoded/danger molecules or the engagement of cytokine receptors by pro-inflammatory mediators produced by antigen presenting cells in the course of the infection. These general recognition strategies, which have been extensively described for innate myeloid cells, are shared by innate lymphoid cells (ILC), such as Natural Killer (NK) cells. The family of ILC has recently expanded with the discovery of group 2 (ILC2) and group 3 ILC (ILC3), which play an important role in the defense against extracellular pathogens. Although ILC3 and NK cells share some phenotypic characteristics, the recognition strategies employed by the various ILC3 subsets have been only partially characterized. In this review, we will describe and comparatively discuss how ILC3 sense environmental cues and how the triggering of different receptors may regulate their functional behavior during an immune response. PMID:24744763

  9. Recognition of local anesthetics by alphabeta+ T cells.

    PubMed

    Zanni, M P; von Greyerz, S; Hari, Y; Schnyder, B; Pichler, W J

    1999-02-01

    Patients with drug allergy show a specific immune response to drugs. Chemically nonreactive drugs like, for example, local anesthetics are directly recognized by alphabeta+ T cells in an HLA-DR restricted way, as neither drug metabolism nor protein processing is required for T cell stimulation. In this study we identified some of the structural requirements that determine cross-reactivity of T cells to local anesthetics, with the aim to improve the molecular basis for the selection of alternatives in individuals sensitized to a certain local anesthetic and to better understand presentation and T cell recognition of these drugs. Fifty-five clones (52 lidocaine specific, three mepivacaine specific from two allergic donors) were analyzed. Stimulatory compounds induced a down-regulation of the T cell receptor, demonstrating that these non-peptide antigens are recognized by the T cell receptor itself. A consistent cross-reactivity between lidocaine and mepivacaine was found, as all except one lidocaine specific clone proliferated to both drugs tested. Sixteen chemically related local anesthetics (including ester local anesthetics, OH- and desalkylated metabolites) were used to identify structural requirements for T cell recognition. Each of the four clones examined in detail was uniquely sensitive to changes in the structures of the local anesthetic: clone SFT24, i.e., did not recognize any of the tested OH- or desalkylated metabolites, while the clone OFB2 proliferated to all OH-metabolites and other differently modified molecules. The broadly reactive clone OFB2 allowed us to propose a model, suggesting that the structure of the amine side chain of local anesthetics is essential for recognition by the T cell receptor.

  10. Pattern recognition monitoring of PEM fuel cell

    DOEpatents

    Meltser, Mark Alexander

    1999-01-01

    The CO-concentration in the H.sub.2 feed stream to a PEM fuel cell stack is monitored by measuring current and voltage behavior patterns from an auxiliary cell attached to the end of the stack. The auxiliary cell is connected to the same oxygen and hydrogen feed manifolds that supply the stack, and discharges through a constant load. Pattern recognition software compares the current and voltage patterns from the auxiliary cell to current and voltage signature determined from a reference cell similar to the auxiliary cell and operated under controlled conditions over a wide range of CO-concentrations in the H.sub.2 fuel stream.

  11. Pattern recognition monitoring of PEM fuel cell

    DOEpatents

    Meltser, M.A.

    1999-08-31

    The CO-concentration in the H{sub 2} feed stream to a PEM fuel cell stack is monitored by measuring current and voltage behavior patterns from an auxiliary cell attached to the end of the stack. The auxiliary cell is connected to the same oxygen and hydrogen feed manifolds that supply the stack, and discharges through a constant load. Pattern recognition software compares the current and voltage patterns from the auxiliary cell to current and voltage signature determined from a reference cell similar to the auxiliary cell and operated under controlled conditions over a wide range of CO-concentrations in the H{sub 2} fuel stream. 4 figs.

  12. Functional role of T-cell receptor nanoclusters in signal initiation and antigen discrimination

    PubMed Central

    Tabarin, Thibault; Yamamoto, Yui; Ma, Yuanqing; Nicovich, Philip R.; Bridgeman, John S.; Cohnen, André; Benzing, Carola; Gao, Yijun; Crowther, Michael D.; Tungatt, Katie; Dolton, Garry; Sewell, Andrew K.; Price, David A.; Acuto, Oreste; Parton, Robert G.; Gooding, J. Justin; Rossy, Jérémie; Rossjohn, Jamie; Gaus, Katharina

    2016-01-01

    Antigen recognition by the T-cell receptor (TCR) is a hallmark of the adaptive immune system. When the TCR engages a peptide bound to the restricting major histocompatibility complex molecule (pMHC), it transmits a signal via the associated CD3 complex. How the extracellular antigen recognition event leads to intracellular phosphorylation remains unclear. Here, we used single-molecule localization microscopy to quantify the organization of TCR–CD3 complexes into nanoscale clusters and to distinguish between triggered and nontriggered TCR–CD3 complexes. We found that only TCR–CD3 complexes in dense clusters were phosphorylated and associated with downstream signaling proteins, demonstrating that the molecular density within clusters dictates signal initiation. Moreover, both pMHC dose and TCR–pMHC affinity determined the density of TCR–CD3 clusters, which scaled with overall phosphorylation levels. Thus, TCR–CD3 clustering translates antigen recognition by the TCR into signal initiation by the CD3 complex, and the formation of dense signaling-competent clusters is a process of antigen discrimination. PMID:27573839

  13. Functional role of T-cell receptor nanoclusters in signal initiation and antigen discrimination.

    PubMed

    Pageon, Sophie V; Tabarin, Thibault; Yamamoto, Yui; Ma, Yuanqing; Bridgeman, John S; Cohnen, André; Benzing, Carola; Gao, Yijun; Crowther, Michael D; Tungatt, Katie; Dolton, Garry; Sewell, Andrew K; Price, David A; Acuto, Oreste; Parton, Robert G; Gooding, J Justin; Rossy, Jérémie; Rossjohn, Jamie; Gaus, Katharina

    2016-09-13

    Antigen recognition by the T-cell receptor (TCR) is a hallmark of the adaptive immune system. When the TCR engages a peptide bound to the restricting major histocompatibility complex molecule (pMHC), it transmits a signal via the associated CD3 complex. How the extracellular antigen recognition event leads to intracellular phosphorylation remains unclear. Here, we used single-molecule localization microscopy to quantify the organization of TCR-CD3 complexes into nanoscale clusters and to distinguish between triggered and nontriggered TCR-CD3 complexes. We found that only TCR-CD3 complexes in dense clusters were phosphorylated and associated with downstream signaling proteins, demonstrating that the molecular density within clusters dictates signal initiation. Moreover, both pMHC dose and TCR-pMHC affinity determined the density of TCR-CD3 clusters, which scaled with overall phosphorylation levels. Thus, TCR-CD3 clustering translates antigen recognition by the TCR into signal initiation by the CD3 complex, and the formation of dense signaling-competent clusters is a process of antigen discrimination.

  14. Responses of bovine WC1(+) gammadelta T cells to protein and nonprotein antigens of Mycobacterium bovis.

    PubMed

    Welsh, Michael D; Kennedy, Hilary E; Smyth, Allister J; Girvin, R Martyn; Andersen, Peter; Pollock, John M

    2002-11-01

    WC1(+) gammadelta T cells of Mycobacterium bovis-infected cattle are highly responsive to M. bovis sonic extract (MBSE). In mycobacterial infections of other species, gammadelta T cells have been shown to respond to protein and nonprotein antigens, but the bovine WC1(+) gammadelta T-cell antigenic targets within MBSE require further definition in terms of the dominance of protein versus nonprotein components. The present study sought to characterize the WC1(+) gammadelta T-cell antigenic targets, together with the role of interleukin-2 (IL-2), in the context of M. bovis infection. This was achieved by testing crude and defined antigens to assess protein versus nonprotein recognition by WC1(+) gammadelta T cells in comparison with CD4(+) alphabeta T cells. Both cell types proliferated strongly in response to MBSE, with CD4(+) T cells being the major producers of gamma interferon (IFN-gamma). However, enzymatic digestion of the protein in MBSE removed its ability to stimulate CD4(+) T-cell responses, whereas some WC1(+) gammadelta T-cell proliferation remained. The most antigenic protein inducing proliferation and IFN-gamma secretion in WC1(+) gammadelta T-cell cultures was found to be ESAT-6, which is a potential novel diagnostic reagent and vaccine candidate. In addition, WC1(+) gammadelta T-cell proliferation was observed in response to stimulation with prenyl pyrophosphate antigens (isopentenyl pyrophosphate and monomethyl phosphate). High levels of cellular activation (CD25 expression) resulted from MBSE stimulation of WC1(+) gammadelta T cells from infected animals. A similar degree of activation was induced by IL-2 alone, but for WC1(+) gammadelta T-cell division IL-2 was found to act only as a costimulatory signal, enhancing antigen-driven responses. Overall, the data indicate that protein antigens are important stimulators of WC1(+) gammadelta T-cell proliferation and IFN-gamma secretion in M. bovis infection, with nonprotein antigens inducing significant

  15. The irre cell recognition module (IRM) proteins.

    PubMed

    Fischbach, Karl-Friedrich; Linneweber, Gerit Arne; Andlauer, Till Felix Malte; Hertenstein, Alexander; Bonengel, Bernhard; Chaudhary, Kokil

    2009-01-01

    One of the most challenging problems in developmental neurosciences is to understand the establishment and maintenance of specific membrane contacts between axonal, dendritic, and glial processes in the neuropils, which eventually secure neuronal connectivity. However, underlying cell recognition events are pivotal in other tissues as well. This brief review focuses on the pleiotropic functions of a small, evolutionarily conserved group of proteins of the immunoglobulin superfamily involved in cell recognition. In Drosophila, this protein family comprises Irregular chiasm C/Roughest (IrreC/Rst), Kin of irre (Kirre), and their interacting protein partners, Sticks and stones (SNS) and Hibris (Hbs). For simplicity, we propose to name this ensemble of proteins the irre cell recognition module (IRM) after the first identified member of this family. Here, we summarize evidence that the IRM proteins function together in various cellular interactions, including myoblast fusion, cell sorting, axonal pathfinding, and target recognition in the optic neuropils of Drosophila. Understanding IRM protein function will help to unravel the epigenetic rules by which the intricate neurite networks in sensory neuropils are formed.

  16. Treatment of solid tumors with chimeric antigen receptor-engineered T cells: current status and future prospects.

    PubMed

    Di, Shengmeng; Li, Zonghai

    2016-04-01

    Chimeric antigen receptors (CARs) are artificial recombinant receptors that generally combine the antigen-recognition domain of a monoclonal antibody with T cell activation domains. Recent years have seen great success in clinical trials employing CD19-specific CAR-T cell therapy for B cell leukemia. Nevertheless, solid tumors remain a major challenge for CAR-T cell therapy. This review summarizes the preclinical and clinical studies on the treatment of solid tumors with CAR-T cells. The major hurdles for the success of CAR-T and the novel strategies to address these hurdles have also been described and discussed.

  17. Ceramide Inhibits Antigen Uptake and Presentation by Dendritic Cells

    PubMed Central

    Sallusto, Federica; Nicolò, Chiara; De Maria, Ruggero; Corinti, Silvia; Testi, Roberto

    1996-01-01

    Ceramides are intramembrane diffusible mediators involved in transducing signals originated from a variety of cell surface receptors. Different adaptive and differentiative cellular responses, including apoptotic cell death, use ceramide-mediated pathways as an essential part of the program. Here, we show that human dendritic cells respond to CD40 ligand, as well as to tumor necrosis factor-α and IL-1β, with intracellular ceramide accumulation, as they are induced to differentiate. Dendritic cells down-modulate their capacity to take up soluble antigens in response to exogenously added or endogenously produced ceramides. This is followed by an impairment in presenting soluble antigens to specific T cell clones, while cell viability and the capacity to stimulate allogeneic responses or to present immunogenic peptides is fully preserved. Thus, ceramide-mediated pathways initiated by different cytokines can actively modulate professional antigen-presenting cell function and antigen-specific immune responses. PMID:8976196

  18. Cell-free antigens of Sporothrix brasiliensis: antigenic diversity and application in an immunoblot assay.

    PubMed

    Almeida-Paes, Rodrigo; Bailão, Alexandre Melo; Pizzini, Cláudia Vera; Reis, Rosani Santos; Soares, Célia Maria de Almeida; Peralta, José Mauro; Gutierrez-Galhardo, Maria Clara; Zancopé-Oliveira, Rosely Maria

    2012-11-01

    Sporotrichosis is a subcutaneous mycosis diagnosed by isolation of the fungus in culture. Serological tests for help in diagnosis in general do not use purified or recombinant antigens, because there is a paucity of described immunoreactive proteins, especially for the new described Sporothrix species, such as Sporothrix brasiliensis. This study aims to characterise antigens from S. brasiliensis and verify their application in serodiagnosis of sporotrichosis. An immunoblot assay allied with computer-based analysis was used to identify putative antigenic molecules in a cell-free extracts of both morphological phases of this fungus, and to delineate antigenic polymorphism among seven S. brasiliensis isolates and one S. schenckii Brazilian strain. The mycelial and yeast phase of the fungus originated 14 and 23 reactive bands, respectively, which were variable in intensity. An 85 kDa antigen, verified in the yeast phase of the fungus, was observed in all strains used and the immunodominant protein was identified. This protein, however, cross-react with serum samples from patients infected with other pathogens. The results show that the S. brasiliensis cell-free antigen extract is a single and inexpensive source of antigens, and can be applied on the sporotrichosis serodiagnosis.

  19. Cancer testis antigen expression in testicular germ cell tumorigenesis.

    PubMed

    Bode, Peter K; Thielken, Andrea; Brandt, Simone; Barghorn, André; Lohe, Bernd; Knuth, Alexander; Moch, Holger

    2014-06-01

    Cancer testis antigens are encoded by germ line-associated genes that are present in normal germ cells of testis and ovary but not in differentiated tissues. Their expression in various human cancer types has been interpreted as 're-expression' or as intratumoral progenitor cell signature. Cancer testis antigen expression patterns have not yet been studied in germ cell tumorigenesis with specific emphasis on intratubular germ cell neoplasia unclassified as a precursor lesion for testicular germ cell tumors. Immunohistochemistry was used to study MAGEA3, MAGEA4, MAGEC1, GAGE1 and CTAG1B expression in 325 primary testicular germ cell tumors, including 94 mixed germ cell tumors. Seminomatous and non-seminomatous components were separately arranged and evaluated on tissue microarrays. Spermatogonia in the normal testis were positive, whereas intratubular germ cell neoplasia unclassified was negative for all five CT antigens. Cancer testis antigen expression was only found in 3% (CTAG1B), 10% (GAGE1, MAGEA4), 33% (MAGEA3) and 40% (MAGEC1) of classic seminoma but not in non-seminomatous testicular germ cell tumors. In contrast, all spermatocytic seminomas were positive for cancer testis antigens. These data are consistent with a different cell origin in spermatocytic seminoma compared with classic seminoma and support a progression model with loss of cancer testis antigens in early tumorigenesis of testicular germ cell tumors and later re-expression in a subset of seminomas.

  20. Antigen specificity of invariant natural killer T-cells.

    PubMed

    Birkholz, Alysia M; Kronenberg, Mitchell

    2015-12-01

    Natural killer T-cells, with an invariant T-cell antigen receptor α-chain (iNKT cells), are unique and conserved subset of lymphocytes capable of altering the immune system through their rapid and potent cytokine responses. They are reactive to lipid antigens presented by the CD1d molecule, an antigen-presenting molecule that is not highly polymorphic. iNKT cell responses frequently involve mixtures of cytokines that work against each other, and therefore attempts are underway to develop synthetic antigens that elicit only strong interferon-gamma (IFNγ) or only strong interleukin-4 responses but not both. Strong IFNγ responses may correlate with tighter binding to CD1d and prolonged stimulation of iNKT cells, and this may be useful for vaccine adjuvants and for stimulating anti-tumor responses. iNKT cells are self-reactive although the structure of the endogenous antigen is controversial. By contrast, bacterial and fungal lipids that engage the T-cell receptor and activate IFNγ from iNKT cells have been identified from both pathogenic and commensal organisms and the responses are in some cases highly protective from pathogens in mice. It is possible that the expanding knowledge of iNKT cell antigens and iNKT cell activation will provide the basis for therapies for patients suffering from infectious and immune diseases and cancer.

  1. T cell recognition of beryllium.

    PubMed

    Dai, Shaodong; Falta, Michael T; Bowerman, Natalie A; McKee, Amy S; Fontenot, Andrew P

    2013-12-01

    Chronic beryllium disease (CBD) is a granulomatous lung disorder caused by a hypersensitivity to beryllium and characterized by the accumulation of beryllium-specific CD4(+) T cells in the lung. Genetic susceptibility to beryllium-induced disease is strongly associated with HLA-DP alleles possessing a glutamic acid at the 69th position of the β-chain (βGlu69). The structure of HLA-DP2, the most prevalent βGlu69-containing molecule, revealed a unique solvent-exposed acidic pocket that includes βGlu69 and represents the putative beryllium-binding site. The delineation of mimotopes and endogenous self-peptides that complete the αβTCR ligand for beryllium-specific CD4(+) T cells suggests a unique role of these peptides in metal ion coordination and the generation of altered self-peptides, blurring the distinction between hypersensitivity and autoimmunity.

  2. Immunological and clinical significance of HLA class I antigen processing machinery component defects in malignant cells

    PubMed Central

    Concha-Benavente, Fernando; Srivastava, Raghvendra; Ferrone, Soldano; Ferris, Robert L.

    2017-01-01

    Experimental as well as clinical studies demonstrate that the immune system plays a major role in controlling generation and progression of tumors. The cancer immunoediting theory supports the notion that tumor cell immunogenicity is dynamically shaped by the immune system, as it eliminates immunogenic tumor cells in the early stage of the disease and then edits their antigenicity. The end result is the generation of a tumor cell population able to escape from immune recognition and elimination by tumor infiltrating lymphocytes. Two major mechanisms, which affect the target cells and the effector phase of the immune response, play a crucial role in the editing process. One is represented by the downregulation of tumor antigen (TA) processing and presentation because of abnormalities in the HLA class I antigen processing machinery (APM). The other one is represented by the anergy of effector immune infiltrates in the tumor microenvironment caused by aberrant inhibitory signals triggered by immune checkpoint receptor (ICR) ligands, such as programmed death ligand-1 (PD-L1). In this review, we will focus on tumor immune escape mechanisms caused by defects in HLA class I APM component expression and/or function in different types of cancer, with emphasis on head and neck cancer (HNC). We will also discuss the immunological implications and clinical relevance of these HLA class I APM abnormalities. Finally, we will describe strategies to counteract defective TA presentation with the expectation that they will enhance tumor recognition and elimination by tumor infiltrating effector T cells. PMID:27264839

  3. Cell-mediated immunity to soluble and particulate inhaled antigens

    PubMed Central

    Hill, J. O.; Burrell, R.

    1979-01-01

    In order to determine the influence of an antigen's physical properties on the development of cell-mediated immunity (CMI) in the lung following aerosol immunization, human serum albumin (HSA) was prepared in either a soluble or a particulate form, the latter being coupled to respirable, carboxylated latex beads. Antigen was administered via an aerosol to groups of guinea-pigs, twice weekly for up to 4 weeks. Additional groups of animals served as unexposed and unconjugated latex controls. Lymphoid cells for CMI assays were isolated from the lung by bronchopulmonary lavage and from blood for use in mitogen- and antigen-induced lymphocyte transformation assays, as well as indirect macrophage migration inhibition tests. Particulate HSA-exposed animals yielded the highest numbers of free lung cells containing predominantly macrophages, with up to 33% lymphocytes. These were followed by the latex control, soluble HSA and unexposed control groups, respectively. Only the animals exposed to particulate HSA had evidence of antigen reactivation in the lung cell populations as measured by lymphocyte stimulation assays. In contrast, a response to polyclonal mitogens was found only in animals exposed to antigen in a soluble form. Data from macrophage depletion experiments suggest that the antigenicity of inhaled antigens may be due to the types and numbers of cells responding to the stimulus, and the subsequent role the alveolar macrophage may play in the modulation of cellular immunity. PMID:393444

  4. Cytomegalovirus-Infected Cells Resist T Cell Mediated Killing in an HLA-Recognition Independent Manner.

    PubMed

    Proff, Julia; Walterskirchen, Christian; Brey, Charlotte; Geyeregger, Rene; Full, Florian; Ensser, Armin; Lehner, Manfred; Holter, Wolfgang

    2016-01-01

    In order to explore the potential of HLA-independent T cell therapy for human cytomegalovirus (HCMV) infections, we developed a chimeric antigen receptor (CAR) directed against the HCMV encoded glycoprotein B (gB), which is expressed at high levels on the surface of infected cells. T cells engineered with this anti-gB CAR recognized HCMV-infected cells and released cytokines and cytotoxic granules. Unexpectedly, and in contrast to analogous approaches for HIV, Hepatitis B or Hepatitis C virus, we found that HCMV-infected cells were resistant to killing by the CAR-modified T cells. In order to elucidate whether this phenomenon was restricted to the use of CARs, we extended our experiments to T cell receptor (TCR)-mediated recognition of infected cells. To this end we infected fibroblasts with HCMV-strains deficient in viral inhibitors of antigenic peptide presentation and targeted these HLA-class I expressing peptide-loaded infected cells with peptide-specific cytotoxic T cells (CTLs). Despite strong degranulation and cytokine production by the T cells, we again found significant inhibition of lysis of HCMV-infected cells. Impairment of cell lysis became detectable 1 day after HCMV infection and gradually increased during the following 3 days. We thus postulate that viral anti-apoptotic factors, known to inhibit suicide of infected host cells, have evolved additional functions to directly abrogate T cell cytotoxicity. In line with this hypothesis, CAR-T cell cytotoxicity was strongly inhibited in non-infected fibroblasts by expression of the HCMV-protein UL37x1, and even more so by additional expression of UL36. Our data extend the current knowledge on Betaherpesviral evasion from T cell immunity and show for the first time that, beyond impaired antigen presentation, infected cells are efficiently protected by direct blockade of cytotoxic effector functions through viral proteins.

  5. Carbohydrate-Mediated Targeting of Antigen to Dendritic Cells Leads to Enhanced Presentation of Antigen to T Cells

    PubMed Central

    Adams, Eddie W.; Ratner, Daniel M.; Seeberger, Peter H.; Hacohen, Nir

    2009-01-01

    The unique therapeutic value of dendritic cells (DCs) for the treatment of allergy, autoimmunity and transplant rejection is predicated upon our ability to selectively deliver antigens, drugs or nucleic acids to DCs in vivo. Here we describe a method for delivering whole protein antigens to DCs based on carbohydrate-mediated targeting of DC-expressed lectins. A series of synthetic carbohydrates was chemically-coupled to a model antigen, ovalbumin (OVA), and each conjugate was evaluated for its ability to increase the efficiency of antigen presentation by murine DCs to OVA-specific T cells (CD4+ and CD8+). In vitro data are presented that demonstrate that carbohydrate modification of OVA leads to a 50-fold enhancement of presentation of antigenic peptide to CD4+ T cells. A tenfold enhancement is observed for CD8+ T cells; this indicates that the targeted lectin(s) can mediate cross-presentation of antigens on MHC class I. Our data indicate that the observed enhancements in antigen presentation are unique to OVA that is conjugated to complex oligosaccharides, such as a high-mannose nonasaccharide, but not to monosaccharides. Taken together, our data suggest that a DC targeting strategy that is based upon carbohydrate-lectin interactions is a promising approach for enhancing antigen presentation via class I and class II molecules. PMID:18186095

  6. Evolution of MHC-based technologies used for detection of antigen-responsive T cells.

    PubMed

    Bentzen, Amalie Kai; Hadrup, Sine Reker

    2017-03-17

    T cell-mediated recognition of peptide-major histocompatibility complex (pMHC) class I and II molecules is crucial for the control of intracellular pathogens and cancer, as well as for stimulation and maintenance of efficient cytotoxic responses. Such interactions may also play a role in the development of autoimmune diseases. Novel insights into this mechanism are crucial to understanding disease development and establishing new treatment strategies. MHC multimers have been used for detection of antigen-responsive T cells since the first report by Altman et al. showed that tetramerization of pMHC class I molecules provided sufficient stability to T cell receptor (TCR)-pMHC interactions, allowing detection of MHC multimer-binding T cells using flow cytometry. Since this breakthrough the scientific community has aimed for expanding the capacity of MHC multimer-based detection technologies to facilitate large-scale epitope discovery and immune monitoring in limited biological material. Screening of T cell specificity using large libraries of pMHC molecules is suitable for analyses of T cell recognition potentially at genome-wide levels rather than analyses restricted to a selection of model antigens. Such strategies provide novel insights into the immune specificities involved in disease development and response to immunotherapy, and extend fundamental knowledge related to T cell recognition patterns and cross-recognition by TCRs. MHC multimer-based technologies have now evolved from detection of 1-2 different T cell specificities per cell sample, to include more than 1000 evaluable pMHC molecules using novel technologies. Here, we provide an overview of MHC multimer-based detection technologies developed over two decades, focusing primarily on MHC class I interactions.

  7. The Memory Function of the B Cell Antigen Receptor.

    PubMed

    Wienands, Jürgen; Engels, Niklas

    2016-01-01

    Activated B lymphocytes preserve their antigen experience by differentiating into long-lived pools of antibody-secreting plasma cells or various types of memory B cells (MBCs). The former population constantly produces serum immunoglobulins with sufficient specificity and affinity to thwart infections with recurrent pathogens. By contrast, memory B cell populations retain their antigen receptors on the cell surface and hence need pathogen-induced differentiation steps before they can actively contribute to host defense. The terminal differentiation of MBCs into antibody-secreting plasma cells is hallmarked by the absence of the lag phase characteristic for primary antibody responses. Moreover, secondary antibody responses are predominantly driven by MBCs that bear an antigen receptor of the IgG class on their surface although IgM-positive memory populations exist as well. These fundamental principles of B cell memory were enigmatic for decades. Only recently, we have begun to understand the underlying mechanisms. This review summarizes our current understanding of how different subpopulations of MBCs are generated during primary immune responses and how their functional heterogeneity on antigen recall is controlled by different signaling capabilities of B cell antigen receptor (BCR) isotypes and by the nature of the antigen.

  8. Evaluation of the Antigen-Experienced B-Cell Receptor Repertoire in Healthy Children and Adults

    PubMed Central

    IJspeert, Hanna; van Schouwenburg, Pauline A.; van Zessen, David; Pico-Knijnenburg, Ingrid; Driessen, Gertjan J.; Stubbs, Andrew P.; van der Burg, Mirjam

    2016-01-01

    Upon antigen recognition via their B cell receptor (BR), B cells migrate to the germinal center where they undergo somatic hypermutation (SHM) to increase their affinity for the antigen, and class switch recombination (CSR) to change the effector function of the secreted antibodies. These steps are essential to create an antigen-experienced BR repertoire that efficiently protects the body against pathogens. At the same time, the BR repertoire should be selected to protect against responses to self-antigen or harmless antigens. Insights into the processes of SHM, selection, and CSR can be obtained by studying the antigen-experienced BR repertoire. Currently, a large reference data set of healthy children and adults, which ranges from neonates to the elderly, is not available. In this study, we analyzed the antigen-experienced repertoire of 38 healthy donors (HD), ranging from cord blood to 74 years old, by sequencing IGA and IGG transcripts using next generation sequencing. This resulted in a large, freely available reference data set containing 412,890 IGA and IGG transcripts. We used this data set to study mutation levels, SHM patterns, antigenic selection, and CSR from birth to elderly HD. Only small differences were observed in SHM patterns, while the mutation levels increase in early childhood and stabilize at 6 years of age at around 7%. Furthermore, comparison of the antigen-experienced repertoire with sequences from the naive immune repertoire showed that features associated with autoimmunity such as long CDR3 length and IGHV4-34 usage are reduced in the antigen-experienced repertoire. Moreover, IGA2 and IGG2 usage was increased in HD in higher age categories, while IGG1 usage was decreased. In addition, we studied clonal relationship in the different samples. Clonally related sequences were found with different subclasses. Interestingly, we found transcripts with the same CDR1–CDR3 sequence, but different subclasses. Together, these data suggest that

  9. From the antigen-presenting cell to the antigen-presenting vesicle: the exosomes.

    PubMed

    Schartz, Noël Emile Célestin; Chaput, Nathalie; André, Fabrice; Zitvogel, Laurence

    2002-08-01

    Exosomes are membrane vesicles of 30 to 100 nm in diameter, of endocytic origin, and are produced and secreted in vitro by living cells of diverse origin. In vivo and in vitro experiments suggest, from their particular proteomic composition, that exosomes are involved in the transfer of tumor antigens to antigen presenting cells, and in the stimulation of a specific immune response. In this review, we provide a molecular characterization of exosomes. The hypotheses accounting for exosome biogenesis will be outlined. Finally, we will describe their bioactivities and discuss their potential relevance and clinical implementation for cancer immunotherapy.

  10. Self-Antigen Presentation by Dendritic Cells in Autoimmunity

    PubMed Central

    Hopp, Ann-Katrin; Rupp, Anne; Lukacs-Kornek, Veronika

    2014-01-01

    The operation of both central and peripheral tolerance ensures the prevention of autoimmune diseases. The maintenance of peripheral tolerance requires self-antigen presentation by professional antigen presenting cells (APCs). Dendritic cells (DCs) are considered as major APCs involved in this process. The current review discusses the role of DCs in autoimmune diseases, the various factors involved in the induction and maintenance of tolerogenic DC phenotype, and pinpoints their therapeutic capacity as well as potential novel targets for future clinical studies. PMID:24592266

  11. Induction of antigen-specific T suppressor cells by soluble Paracoccidioides brasiliensis antigen.

    PubMed Central

    Jimenez-Finkel, B E; Murphy, J W

    1988-01-01

    In naturally acquired paracoccidioidomycosis, patients have depressed in vivo and in vitro cell-mediated immune (CMI) responses to Paracoccidioides brasiliensis antigen. In addition, it has been reported that these patients have significant levels of circulating paracoccidioidal antigen in their sera. The primary purpose of this investigation was to assess the effects of P. brasiliensis antigen on the CMI responses in a mouse model. On the basis of findings with other fungal agents, we predicted that circulating paracoccidioidal antigen may be inducing suppressor cells which modulate the CMI response. In this study, we show (i) that a soluble P. brasiliensis culture filtrate antigen (Pb.Ag) emulsified in complete Freund adjuvant and injected subcutaneously into mice induces reasonably high levels of delayed-type hypersensitivity (DTH) in CBA/J mice; (ii) that Pb.Ag elicits DTH reactions specific for P. brasiliensis when injected into footpads of immunized mice; and (iii) that an intravenous injection of Pb.Ag induces a population of lymph node and spleen cells which, upon adoptive transfer, suppress the afferent limb of the DTH response to paracoccidioidal antigen. The afferent suppressor cells can be detected in spleens as early as 5 days after Pb.Ag treatment, are present in significant numbers by 7 days in both spleens and lymph nodes, and are virtually absent by 14 days. In contrast, at 14 days after antigen injection, efferent suppressor cells were detected in spleens and lymph nodes. The Pb.Ag-induced afferent suppressor cells specifically inhibit the antiparacoccidioidal DTH response. They are nylon wool-nonadherent cells, and their activity is abrogated by anti-Thy-1 and complement treatment, indicating that they are T lymphocytes. The phenotype of these afferent suppressor T cells is L3T4+ Lyt-1+2- I-J+. The Pb.Ag-specific suppressor cells described in this paper are similar to the Ts1 cells in the azobenzenearsonate, 4-hydroxy-3-nitrophenyl acetyl, and

  12. Multimolecular associations of the T-cell antigen receptor.

    PubMed

    Beyers, A D; Spruyt, L L; Williams, A F

    1992-09-01

    T cells are activated when the T-cell receptor for antigen (TCR) interacts with an antigenic peptide bound to a major histocompatibility complex (MHC) molecule on the surface of another cell. It is often assumed that T-cell activation is induced by the crosslinking of TCRs. In this article, Albertus Beyers, Louise Spruyt and Alan Williams argue that this mechanism is not generally applicable. They hypothesize that the key event in T-cell activation is the formation of multimolecular complexes consisting of the TCR and several other polypeptides, including CD4 or CD8, CD2, CD5 and the associated tyrosine kinases p59(fyn) and p56(lck).

  13. Chimeric antigen receptor T-cell therapy for solid tumors

    PubMed Central

    Newick, Kheng; Moon, Edmund; Albelda, Steven M

    2016-01-01

    Chimeric antigen receptor (CAR) T cells are engineered constructs composed of synthetic receptors that direct T cells to surface antigens for subsequent elimination. Many CAR constructs are also manufactured with elements that augment T-cell persistence and activity. To date, CAR T cells have demonstrated tremendous success in eradicating hematological malignancies (e.g., CD19 CARs in leukemias). This success is not yet extrapolated to solid tumors, and the reasons for this are being actively investigated. Here in this mini-review, we discuss some of the key hurdles encountered by CAR T cells in the solid tumor microenvironment. PMID:27162934

  14. The CD1 family: serving lipid antigens to T cells since the Mesozoic era.

    PubMed

    Zajonc, Dirk M

    2016-08-01

    Class I-like CD1 molecules are in a family of antigen-presenting molecules that bind lipids and lipopeptides, rather than peptides for immune surveillance by T cells. Since CD1 lacks the high degree of polymorphism found in their major histocompatibility complex (MHC) class I molecules, different species express different numbers of CD1 isotypes, likely to be able to present structurally diverse classes of lipid antigens. In this review, we will present a historical overview of the structures of the different human CD1 isotypes and also discuss species-specific adaptations of the lipid-binding groove. We will discuss how single amino acid changes alter the shape and volume of the CD1 binding groove, how these minor changes can give rise to different numbers of binding pockets, and how these pockets affect the lipid repertoire that can be presented by any given CD1 protein. We will compare the structures of various lipid antigens and finally, we will discuss recognition of CD1-presented lipid antigens by antigen receptors on T cells (TCRs).

  15. Autopresentation of hepatitis B virus envelope antigens by T cells.

    PubMed Central

    Ferrari, C; Pilli, M; Penna, A; Bertoletti, A; Valli, A; Cavalli, A; Pasetti, G; Fiaccadori, F

    1992-01-01

    Processing and presentation by T cells appear to be limited to antigens that can directly interact with the T-cell surface, thereby overcoming the T-cell inefficiency in antigen capture and internalization. Our study provides evidence that the hepatitis B virus (HBV) envelope proteins can also be efficiently processed and presented by CD4+ and CD8+ T cells to other T cells in a human leukocyte antigen class II-restricted fashion. This phenomenon suggests a receptor-mediated interaction between T cells and the HBV envelope and defines a system that can, we hope, be exploited for the identification of the receptor binding site within the HBV envelope and for the characterization of the putative cellular HBV receptor. PMID:1548778

  16. Identification of Theileria lestoquardi Antigens Recognized by CD8+ T Cells

    PubMed Central

    Ngugi, Daniel; Lizundia, Regina; Hostettler, Isabel; Woods, Kerry; Ballingall, Keith; MacHugh, Niall D.; Morrison, W. Ivan; Weir, Willie; Shiels, Brian; Werling, Dirk

    2016-01-01

    As part of an international effort to develop vaccines for Theileria lestoquardi, we undertook a limited screen to test T. lestoquardi orthologues of antigens recognised by CD8+ T lymphocyte responses against T. annulata and T. parva in cattle. Five MHC defined sheep were immunized by live T. lestoquardi infection and their CD8+ T lymphocyte responses determined. Thirteen T. lestoquardi orthologues of T. parva and T. annulata genes, previously shown to be targets of CD8+ T lymphocyte responses of immune cattle, were expressed in autologous fibroblasts and screened for T cell recognition using an IFNγ assay. Genes encoding T. lestoquardi antigens Tl8 (putative cysteine proteinase, 349 aa) or Tl9 (hypothetical secreted protein, 293 aa) were recognise by T cells from one animal that displayed a unique MHC class I genotype. Antigenic 9-mer peptide epitopes of Tl8 and Tl9 were identified through peptide scans using CD8+ T cells from the responding animal. These experiments identify the first T. lestoquardi antigens recognised by CD8+ T cell responses linked to specific MHC class I alleles. PMID:27611868

  17. Coproduction of carcinoembryonic antigen and nonspecific cross-reacting antigen by a continuous cell line from a human pancreatic tumor.

    PubMed

    Kuroki, M; Ichiki, S; Kuroki, M; Matsuoka, Y

    1982-08-01

    A simultaneous production of nonspecific cross-reacting antigen (NCA) and carcinoembryonic antigen (CEA) by the same individual cells of an established human pancreatic cell line (QGP-1) was demonstrated by the immunoperoxidase method. Kinetics of cell proliferation and production of CEA and NCA were analyzed, and active synthesis of both antigens was found to be accompanied with the active proliferation of cultured cells. Both antigens in culture medium were purified by immunoadsorption and gel filtration. Immunochemical studies confirmed that CEA and NCA produced by the QGP-1 cells had properties identical to those of authentic CEA derived from metastatic colorectal carcinoma and to those of NCA from normal lungs, respectively.

  18. Recognition of the Thomsen-Friedenreich Pancarcinoma Carbohydrate Antigen by a Lamprey Variable Lymphocyte Receptor*

    PubMed Central

    Luo, Ming; Velikovsky, C. Alejandro; Yang, Xinbo; Siddiqui, Maqbool A.; Hong, Xia; Barchi, Joseph J.; Gildersleeve, Jeffrey C.; Pancer, Zeev; Mariuzza, Roy A.

    2013-01-01

    Variable lymphocyte receptors (VLRs) are leucine-rich repeat proteins that mediate adaptive immunity in jawless vertebrates. VLRs were recently shown to recognize glycans, such as the tumor-associated Thomsen-Friedenreich antigen (TFα; Galβ1–3GalNAcα), with a selectivity rivaling or exceeding that of lectins and antibodies. To understand the basis for TFα recognition by one such VLR (VLRB.aGPA.23), we measured thermodynamic parameters for the binding interaction and determined the structure of the VLRB.aGPA.23-TFα complex to 2.2 Å resolution. In the structure, four tryptophan residues form a tight hydrophobic cage encasing the TFα disaccharide that completely excludes buried water molecules. This cage together with hydrogen bonding of sugar hydroxyls to polar side chains explains the exquisite selectivity of VLRB.aGPA.23. The topology of the glycan-binding site of VLRB.aGPA.23 differs markedly from those of lectins or antibodies, which typically consist of long, convex grooves for accommodating the oligosaccharide. Instead, the TFα disaccharide is sandwiched between a variable loop and the concave surface of the VLR formed by the β-strands of the leucine-rich repeat modules. Longer oligosaccharides are predicted to extend perpendicularly across the β-strands, requiring them to bend to match the concavity of the VLR solenoid. PMID:23782692

  19. Atypical Antigen Recognition Mode of a Shark Immunoglobulin New Antigen Receptor (IgNAR) Variable Domain Characterized by Humanization and Structural Analysis

    PubMed Central

    Kovalenko, Oleg V.; Olland, Andrea; Piché-Nicholas, Nicole; Godbole, Adarsh; King, Daniel; Svenson, Kristine; Calabro, Valerie; Müller, Mischa R.; Barelle, Caroline J.; Somers, William; Gill, Davinder S.; Mosyak, Lidia; Tchistiakova, Lioudmila

    2013-01-01

    The immunoglobulin new antigen receptors (IgNARs) are a class of Ig-like molecules of the shark immune system that exist as heavy chain-only homodimers and bind antigens by their single domain variable regions (V-NARs). Following shark immunization and/or in vitro selection, V-NARs can be generated as soluble, stable, and specific high affinity monomeric binding proteins of ∼12 kDa. We have previously isolated a V-NAR from an immunized spiny dogfish shark, named E06, that binds specifically and with high affinity to human, mouse, and rat serum albumins. Humanization of E06 was carried out by converting over 60% of non-complementarity-determining region residues to those of a human germ line Vκ1 sequence, DPK9. The resulting huE06 molecules have largely retained the specificity and affinity of antigen binding of the parental V-NAR. Crystal structures of the shark E06 and its humanized variant (huE06 v1.1) in complex with human serum albumin (HSA) were determined at 3- and 2.3-Å resolution, respectively. The huE06 v1.1 molecule retained all but one amino acid residues involved in the binding site for HSA. Structural analysis of these V-NARs has revealed an unusual variable domain-antigen interaction. E06 interacts with HSA in an atypical mode that utilizes extensive framework contacts in addition to complementarity-determining regions that has not been seen previously in V-NARs. On the basis of the structure, the roles of various elements of the molecule are described with respect to antigen binding and V-NAR stability. This information broadens the general understanding of antigen recognition and provides a framework for further design and humanization of shark IgNARs. PMID:23632026

  20. Atypical antigen recognition mode of a shark immunoglobulin new antigen receptor (IgNAR) variable domain characterized by humanization and structural analysis.

    PubMed

    Kovalenko, Oleg V; Olland, Andrea; Piché-Nicholas, Nicole; Godbole, Adarsh; King, Daniel; Svenson, Kristine; Calabro, Valerie; Müller, Mischa R; Barelle, Caroline J; Somers, William; Gill, Davinder S; Mosyak, Lidia; Tchistiakova, Lioudmila

    2013-06-14

    The immunoglobulin new antigen receptors (IgNARs) are a class of Ig-like molecules of the shark immune system that exist as heavy chain-only homodimers and bind antigens by their single domain variable regions (V-NARs). Following shark immunization and/or in vitro selection, V-NARs can be generated as soluble, stable, and specific high affinity monomeric binding proteins of ∼12 kDa. We have previously isolated a V-NAR from an immunized spiny dogfish shark, named E06, that binds specifically and with high affinity to human, mouse, and rat serum albumins. Humanization of E06 was carried out by converting over 60% of non-complementarity-determining region residues to those of a human germ line Vκ1 sequence, DPK9. The resulting huE06 molecules have largely retained the specificity and affinity of antigen binding of the parental V-NAR. Crystal structures of the shark E06 and its humanized variant (huE06 v1.1) in complex with human serum albumin (HSA) were determined at 3- and 2.3-Å resolution, respectively. The huE06 v1.1 molecule retained all but one amino acid residues involved in the binding site for HSA. Structural analysis of these V-NARs has revealed an unusual variable domain-antigen interaction. E06 interacts with HSA in an atypical mode that utilizes extensive framework contacts in addition to complementarity-determining regions that has not been seen previously in V-NARs. On the basis of the structure, the roles of various elements of the molecule are described with respect to antigen binding and V-NAR stability. This information broadens the general understanding of antigen recognition and provides a framework for further design and humanization of shark IgNARs.

  1. Semiquantitative measure of immune responses against erythropoietic stem cell antigens

    SciTech Connect

    Harrison, D.E.

    1987-01-01

    A semiquantitative assay was developed and used to measure the effects of immune responses against 16 independent non-H-2 antigenic loci on erythropoietic stem cells. The assay compares repopulation in genetically anemic WBB6F1-W/Wv recipients that have normal immune responses, and in lethally irradiated WBB6F1 +/+ mice whose immune responses are suppressed by the irradiation. The differences in repopulating ability between these two types of recipients measure how immune responses affect erythropoietic stem cells. Stem cell repopulating abilities for the cells with antigens specified by the Thy-1, H-1, H-24, Ly-1, H-37, and H-17 loci were affected slightly, if at all. Repopulating abilities were moderately reduced by responses against antigens specified by H-15, 16, Ea-2, and Ly-2, 3 loci, and against the differences between the B6 and B10 genotypes, although marrow of these types cured W/Wv recipients. A surprising result occurred for the antigen specified by the H-8 locus, in which immune responses strongly reduced repopulating abilities, although this type of marrow cell cured W/Wv recipients. A comparison of these results with skin graft survival times suggests that the antigens specified by the H-17 and H-24 loci are strongly immunogenic on skin but not on marrow stem cells, while those specified by the H-12 and H-8 loci are strongly immunogenic on marrow stem cells but not on skin.

  2. Antibody-induced antigenic modulation is antigen dependent: characterization of 22 proteins on a malignant human B cell line

    SciTech Connect

    Pesando, J.M.; Hoffman, P.; Abed, M.

    1986-12-01

    Expression of several of the surface antigens on normal and malignant hematopoietic cells is reduced or is modulated by incubation with specific antibodies. Although antigenic modulation provides a means by which cells can escape antibody-mediated immune destruction, the physiologic significance and frequency of this phenomenon are both poorly understood. To begin to address these issues, the authors identified and characterized surface antigens on the malignant B cell line Laz 221 established from a patient with acute lymphoblastic leukemia (ALL). Indirect immunofluorescence analysis with the use of 26 hematopoietic cell populations and immune precipitation studies with the use of iodinated ALL cells indicate the 163 monoclonal antibodies (MoAb) identify 22 different proteins on this cell line, including at least six previously described surface molecules. Seven of these antigens are expressed by all nucleated cells examined, whereas only the ..mu.. chain of immunoglobulin is B cell specific. Studies that made use of multiple MoAb specific for the same antigen suggest that the capacity for antigenic modulation is an intrinsic property of individual antigens. These studies also suggest that the murine immune response to shared human antigens varies from one immunizing cell population to another. Immunogenicity of individual human antigens in the mouse may be a function of their cell surface environment.

  3. The effect of antigen encapsulation in chitosan particles on uptake, activation and presentation by antigen presenting cells.

    PubMed

    Koppolu, Bhanuprasanth; Zaharoff, David A

    2013-03-01

    Particle-based vaccine delivery systems are under exploration to enhance antigen-specific immunity against safe but poorly immunogenic polypeptide antigens. Chitosan is a promising biomaterial for antigen encapsulation and delivery due to its ability to form nano- and microparticles in mild aqueous conditions thus preserving the antigenicity of loaded polypeptides. In this study, the influence of chitosan encapsulation on antigen uptake, activation and presentation by antigen presenting cells (APCs) is explored. Fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) and ovalbumin (OVA) were used as model protein antigens and encapsulated in chitosan particles via precipitation-coacervation at loading efficiencies >89%. Formulation conditions were manipulated to create antigen-encapsulated chitosan particles (AgCPs) with discrete nominal sizes (300 nm, 1 μm, and 3 μm). Uptake of AgCPs by dendritic cells and macrophages was found to be dependent on particle size, antigen concentration and exposure time. Flow cytometry analysis revealed that uptake of AgCPs enhanced upregulation of surface activation markers on APCs and increased the release of pro-inflammatory cytokines. Lastly, antigen-specific T cells exhibited higher proliferative responses when stimulated with APCs activated with AgCPs versus soluble antigen. These data suggest that encapsulation of antigens in chitosan particles enhances uptake, activation and presentation by APCs.

  4. Variable expression of activation-linked surface antigens on human mast cells in health and disease.

    PubMed

    Valent, P; Schernthaner, G H; Sperr, W R; Fritsch, G; Agis, H; Willheim, M; Bühring, H J; Orfao, A; Escribano, L

    2001-02-01

    Mast cells (MC) are multipotent effector cells of the immune system. They contain an array of biologically active mediator substances in their granules. MC also express a number of functionally important cell surface antigens, including stem cell factor receptor (SCFR=kit=CD117), high affinity IgER (FcepsilonRI), or CSaR (CD88). Respective ligands can induce or promote degranulation, migration, or cytokine production. Other integral surface molecules can mediate adhesion or cell aggregation. Recent data suggest that a number of critical molecules are variably expressed on the surface of human MC. In fact, depending on the environment (organ), stage of cell maturation, type of disease, and other factors, MC express variable amounts of activation-linked antigens (CD25, CD63, CD69, CD88), cell recognition molecules (CD2, CD11, CD18, CD50, CD54), or cytokine receptors. At present, however, little is known about the mechanisms and regulation of expression of such antigens. The present article gives an overview of MC phenotypes in health and disease, and attempts to provide explanations for the phenotypic variability of MC.

  5. Synovial fluid antigen-presenting cells unmask peripheral blood T cell responses to bacterial antigens in inflammatory arthritis.

    PubMed Central

    Life, P F; Viner, N J; Bacon, P A; Gaston, J S

    1990-01-01

    We and others have previously shown that synovial fluid (SF) mononuclear cells (MC) from patients with both reactive arthritis and other inflammatory arthritides proliferate in vitro in response to bacteria clinically associated with the triggering of reactive arthritis. In all cases, such SFMC responses are greater than the corresponding peripheral blood (PB) MC responses, often markedly so, and the mechanism for this is unclear. We have investigated this phenomenon by comparing the relative abilities of irradiated non-T cells derived from PB and SF to support autologous T cell responses to ReA-associated bacteria. Seven patients whose SFMC had been shown previously to respond to bacteria were studied. We demonstrate antigen-specific responses of PB T cells to bacteria in the presence of SF non-T cells which are in marked contrast to the minimal responses of either unfractionated PBMC or PB T cells reconstituted with PB non-T cells. We also show that PB, but not SF T cells respond strongly to autologous SF non-T cells in the absence of antigen or mitogen. These findings demonstrate that SF antigen-presenting cells (APC) are potent activators of PB T cells. We conclude that the contrasting responses of SFMC and PBMC to bacterial antigens may be accounted for at least in part by an enhanced ability of SF APC to support T cell proliferative responses. PMID:2311298

  6. T Cells as Antigen Carriers for Anti-tumor Vaccination.

    PubMed

    Traversari, Catia; Russo, Vincenzo

    2016-01-01

    The exploitation of the physiologic processing and presenting machinery of dendritic cells (DCs) by in vivo loading of tumor-associated antigens may improve the immunogenic potential and clinical efficacy of DC-based cancer vaccines. The approach developed by our group was based on the clinical observation that some patients treated with the infusion of donor lymphocytes transduced to express the HSV-TK suicide gene for relapse of hematologic malignancies, after allogeneic hematopoietic stem cell transplantation, developed a T cell-mediated immune response specifically directed against the HSV-TK gene product.We demonstrated that lymphocytes genetically modified to express HSV-TK as well as self/tumor antigens, acting as antigen carriers, efficiently target DCs in vivo in tumor-bearing mice. The infusion of TRP-2-transduced lymphocytes induced the establishment of protective immunity and long-term memory in tumor-bearing mice by cross-presentation of the antigen mediated by the CD11c(+)CD8a(+) DCs subset. A similar approach was applied in a clinical setting. Ten patients affected by MAGE-3(+) metastatic melanoma were treated with autologous lymphocytes retrovirally transduced to express the MAGE-3 tumor antigen. In three patients, the treatment led to the increase of MAGE-3 specific CD8+ and CD4+ effectors and the development of long-term memory, which ultimately correlated with a favorable clinical outcome. Transduced lymphocytes represent an efficient way for in vivo loading of tumor-associated antigens of DCs.

  7. Cell-to-cell transfer of M. tuberculosis antigens optimizes CD4 T cell priming.

    PubMed

    Srivastava, Smita; Ernst, Joel D

    2014-06-11

    During Mycobacterium tuberculosis and other respiratory infections, optimal T cell activation requires pathogen transport from the lung to a local draining lymph node (LN). However, the infected inflammatory monocyte-derived dendritic cells (DCs) that transport M. tuberculosis to the local lymph node are relatively inefficient at activating CD4 T cells, possibly due to bacterial inhibition of antigen presentation. We found that infected migratory DCs release M. tuberculosis antigens as soluble, unprocessed proteins for uptake and presentation by uninfected resident lymph node DCs. This transfer of bacterial proteins from migratory to local DCs results in optimal priming of antigen-specific CD4 T cells, which are essential in controlling tuberculosis. Additionally, this mechanism does not involve transfer of the whole bacterium and is distinct from apoptosis or exosome shedding. These findings reveal a mechanism that bypasses pathogen inhibition of antigen presentation by infected cells and generates CD4 T cell responses that control the infection.

  8. C19orf48 Encodes a Minor Histocompatibility Antigen Recognized by CD8+ Cytotoxic T Cells from Renal Cell Carcinoma Patients

    PubMed Central

    Tykodi, Scott S.; Fujii, Nobuharu; Vigneron, Nathalie; Lu, Sharon M.; Mito, Jeffrey K.; Miranda, Maureen X.; Chou, Jeffrey; Voong, Lilien N.; Thompson, John A.; Sandmaier, Brenda M.; Cresswell, Peter; Van den Eynde, Benoît; Riddell, Stanley R.; Warren, Edus H.

    2009-01-01

    Purpose Tumor regression has been observed in some patients with metastatic renal cell carcinoma (RCC) after nonmyeloablative allogeneic hematopoietic cell transplantation (HCT). Cellular and molecular characterization of antigens recognized by tumor-reactive T cells isolated from responding patients could potentially provide insight into the mechanisms of tumor regression. Experimental Design CD8+ cytotoxic T lymphocyte (CTL) clones that recognized a novel RCC-associated minor histocompatibility (H) antigen presented by HLA-A*0201 were isolated from two patients with metastatic RCC who experienced tumor regression or stable disease following nonmyeloablative allogeneic HCT. These clones were used to screen a cDNA library and isolate the unique cDNA encoding the antigen. Results An alternative open reading frame in the C19orf48 gene located on chromosome 19q13 encodes the HLA-A*0201-restricted minor H antigen recognized by the RCC-reactive T cells. Differential T cell recognition of donor- and recipient-derived target cells is attributable to a nonsynonymous single nucleotide polymorphism within the nucleotide interval that encodes the antigenic peptide. Assays for gene expression and CTL recognition demonstrated that the C19orf48-encoded peptide is widely expressed in renal tumors and solid tumors of other histologies. The antigenic peptide can be processed for CTL recognition via both TAP-dependent and TAP-independent pathways. Conclusions Donor T cell responses against the HLA-A*0201-restricted minor H antigen encoded by C19orf48 may contribute to RCC regression after MHC-matched allogeneic HCT. PMID:18698046

  9. Characterization of antigen association with accessory cells: specific removal of processed antigens from the cell surface by phospholipases.

    PubMed Central

    Falo, L D; Haber, S I; Herrmann, S; Benacerraf, B; Rock, K L

    1987-01-01

    To characterize the basis for the cell surface association of processed antigen with the antigen-presenting cell (APC) we analyzed its sensitivity to enzymatic digestion. Antigen-exposed APC that are treated with phospholipase and then immediately fixed lose their ability to stimulate antigen-plus-Ia-specific T-T hybridomas. This effect is seen with highly purified phospholipase A2 and phospholipase C. In addition it is observed with three distinct antigens--ovalbumin, bovine insulin, and poly(LGlu56LLys35LPhe9) [(GluLysPhe)n]. The effect of phospholipases is highly specific. Identically treated APC are equivalent to controls in their ability to stimulate alloreactive hybridomas specific for precisely the same Ia molecule that is corecognized by antigen-plus-Ia-specific hybrids. Furthermore, the antigen-presenting function of enzyme-treated, fixed APC can be reconstituted by the addition of exogenous in vitro processed or "processing independent" antigens. In parallel studies 125I-labeled avidin was shown to specifically bind to APC that were previously exposed and allowed to process biotin-insulin. Biotin-insulin-exposed APC that are pretreated with phospholipase bind significantly less 125I-labeled avidin than do untreated, exposed APC. Identical enzyme treatment does not reduce the binding of avidin to a biotinylated antibody already bound to class II major histocompatibility complex molecules of APC. At least some of the biotin-insulin surface sites are immunologically relevant, because the presentation of processed biotin-insulin by fixed APC is blocked by avidin. This effect is specific. Avidin binding to biotin-insulin-exposed APC does not inhibit allospecific stimulation nor the presentation of unconjugated insulin. These studies demonstrate that phospholipase effectively removes processed cell surface antigen. PMID:3467371

  10. Modulation of human natural killer T cell ligands on TLR-mediated antigen-presenting cell activation.

    PubMed

    Salio, Mariolina; Speak, Anneliese O; Shepherd, Dawn; Polzella, Paolo; Illarionov, Petr A; Veerapen, Natacha; Besra, Gurdyal S; Platt, Frances M; Cerundolo, Vincenzo

    2007-12-18

    Invariant natural killer T (iNKT) cells are a subset of nonconventional T cells recognizing endogenous and/or exogenous glycolipid antigens in the context of CD1d molecules. It remains unclear whether innate stimuli can modify the profile of endogenous lipids recognized by iNKT cells on the surface of antigen-presenting cells (APCs). We report that activation of human APCs by Toll-like receptor ligands (TLR-L) modulates the lipid biosynthetic pathway, resulting in enhanced recognition of CD1d-associated lipids by iNKT cells, as defined by IFN-gamma secretion. APC-derived soluble factors further increase CD1d-restricted iNKT cell activation. Finally, using soluble tetrameric iNKT T cell receptors (TCR) as a staining reagent, we demonstrate specific up-regulation of CD1d-bound ligand(s) on TLR-mediated APC maturation. The ability of innate stimuli to modulate the lipid profile of APCs resulting in iNKT cell activation and APC maturation underscores the role of iNKT cells in assisting priming of antigen-specific immune responses.

  11. Modulation of human natural killer T cell ligands on TLR-mediated antigen-presenting cell activation

    PubMed Central

    Salio, Mariolina; Speak, Anneliese O.; Shepherd, Dawn; Polzella, Paolo; Illarionov, Petr A.; Veerapen, Natacha; Besra, Gurdyal S.; Platt, Frances M.; Cerundolo, Vincenzo

    2007-01-01

    Invariant natural killer T (iNKT) cells are a subset of nonconventional T cells recognizing endogenous and/or exogenous glycolipid antigens in the context of CD1d molecules. It remains unclear whether innate stimuli can modify the profile of endogenous lipids recognized by iNKT cells on the surface of antigen-presenting cells (APCs). We report that activation of human APCs by Toll-like receptor ligands (TLR-L) modulates the lipid biosynthetic pathway, resulting in enhanced recognition of CD1d-associated lipids by iNKT cells, as defined by IFN-γ secretion. APC-derived soluble factors further increase CD1d-restricted iNKT cell activation. Finally, using soluble tetrameric iNKT T cell receptors (TCR) as a staining reagent, we demonstrate specific up-regulation of CD1d-bound ligand(s) on TLR-mediated APC maturation. The ability of innate stimuli to modulate the lipid profile of APCs resulting in iNKT cell activation and APC maturation underscores the role of iNKT cells in assisting priming of antigen-specific immune responses. PMID:18077358

  12. Activated Brain Endothelial Cells Cross-Present Malaria Antigen.

    PubMed

    Howland, Shanshan W; Poh, Chek Meng; Rénia, Laurent

    2015-06-01

    In the murine model of cerebral malaria caused by P. berghei ANKA (PbA), parasite-specific CD8+ T cells directly induce pathology and have long been hypothesized to kill brain endothelial cells that have internalized PbA antigen. We previously reported that brain microvessel fragments from infected mice cross-present PbA epitopes, using reporter cells transduced with epitope-specific T cell receptors. Here, we confirm that endothelial cells are the population responsible for cross-presentation in vivo, not pericytes or microglia. PbA antigen cross-presentation by primary brain endothelial cells in vitro confers susceptibility to killing by CD8+ T cells from infected mice. IFNγ stimulation is required for brain endothelial cross-presentation in vivo and in vitro, which occurs by a proteasome- and TAP-dependent mechanism. Parasite strains that do not induce cerebral malaria were phagocytosed and cross-presented less efficiently than PbA in vitro. The main source of antigen appears to be free merozoites, which were avidly phagocytosed. A human brain endothelial cell line also phagocytosed P. falciparum merozoites. Besides being the first demonstration of cross-presentation by brain endothelial cells, our results suggest that interfering with merozoite phagocytosis or antigen processing may be effective strategies for cerebral malaria intervention.

  13. Design and Development of Therapies using Chimeric Antigen Receptor-Expressing T cells

    PubMed Central

    Dotti, Gianpietro; Gottschalk, Stephen; Savoldo, Barbara; Brenner, Malcolm K

    2013-01-01

    Summary Investigators developed chimeric antigen receptors (CARs) for expression on T cells more than 25 years ago. When the CAR is derived from an antibody, the resultant cell should combine the desirable targeting features of an antibody (e.g. lack of requirement for major histocompatibility complex recognition, ability to recognize non-protein antigens) with the persistence, trafficking and effector functions of a T-cell. This article describes how the past two decades have seen a crescendo of research which has now begun to translate these potential benefits into effective treatments for patients with cancer. We describe the basic design of CARs, describe how antigenic targets are selected, and the initial clinical experience with CART cells. Our review then describes our own and other investigators’ work aimed at improving the function of CARs and reviews the clinical studies in hematological and solid malignancies that are beginning to exploit these approaches. Finally, we show the value of adding additional engineering features to CAR-T cells, irrespective of their target, to render them better suited to function in the tumor environment, and discuss how the safety of these heavily modified cells may be maintained. PMID:24329793

  14. Unusual Water-mediated Antigenic Recognition of the Proinflammatory Cytokine Interleukin-18

    SciTech Connect

    Argiriadi, Maria A.; Xiang, Tao; Wu, Chengbin; Ghayur, Tariq; Borhani, David W.

    2009-10-21

    The unique cytokine interleukin-18 (IL-18) acts synergistically with IL-12 to regulate T-helper 1 and 2 lymphocytes and, as such, seems to underlie the pathogenesis of various autoimmune and allergic diseases. Several anti-IL-18 agents are in clinical development, including the recombinant human antibody ABT-325, which is entering trials for autoimmune diseases. Given competing cytokine/receptor and cytokine/receptor decoy interactions, understanding the structural basis for recognition is critical for effective development of anti-cytokine therapies. Here we report three crystal structures: the murine antibody 125-2H Fab fragment bound to human IL-18, at 1.5 {angstrom} resolution; the 125-2H Fab (2.3 {angstrom}); and the ABT-325 Fab (1.5 {angstrom}). These structures, along with human/mouse IL-18 chimera binding data, allow us to make three key observations relevant to the biology and antigenic recognition of IL-18 and related cytokines. First, several IL-18 residues shift dramatically (>10 {angstrom}) upon binding 125-2H, compared with unbound IL-18 (Kato, Z., Jee, J., Shikano, H., Mishima, M., Ohki, I., Ohnishi, H., Li, A., Hashimoto, K., Matsukuma, E., Omoya, K., Yamamoto, Y., Yoneda, T., Hara, T., Kondo, N., and Shirakawa, M. (2003) Nat. Struct. Biol. 10, 966-971). IL-18 thus exhibits plasticity that may be common to its interactions with other receptors. Related cytokines may exhibit similar plasticity. Second, ABT-325 and 125-2H differ significantly in combining site character and architecture, thus explaining their ability to bind IL-18 simultaneously at distinct epitopes. These data allow us to define the likely ABT-325 epitope and thereby explain the distinct neutralizing mechanisms of both antibodies. Third, given the high 125-2H potency, 10 well ordered water molecules are trapped upon complex formation in a cavity between two IL-18 loops and all six 125-2H complementarity-determining regions. Thus, counterintuitively, tight and specific antibody

  15. Induction of the autoantigen proliferating cell nuclear antigen in T lymphocytes by a mycobacterial antigen.

    PubMed Central

    Haftel, H M; Chang, Y; Hinderer, R; Hanash, S M; Holoshitz, J

    1994-01-01

    Mycobacteria have been implicated in the pathogenesis of autoimmunity. To determine the potential effect of mycobacterial antigens on peripheral blood mononuclear cells (PBMC), we analyzed PBMC incubated with the acetone-precipitable fraction of Mycobacterium tuberculosis (APMT) for changes in cellular protein expression. Two-dimensional gel analysis showed induction of a 36-kD polypeptide identified as proliferating cell nuclear antigen (PCNA), a known autoantigen, after incubation with AP-MT. PCNA plays a role in cell proliferation and is expressed as a late growth regulated factor. However, its synthesis in response to AP-MT was induced as an early event. The early induction of PCNA was regulated at a posttranscriptional level and was restricted to T cells. Treatment of PBMC with known T cell mitogens, namely PHA, anti-CD3 antibodies, and staphylococcal superantigens failed to induce an early PCNA increase. The distinct characteristics of the AP-MT effect on PCNA expression suggest a separate mechanism of induction in response to AP-MT, compared with the late increase observed in response to mitogens. The induction of PCNA in response to mycobacterial antigens may represent a pathogenically relevant mechanism in autoimmunity. Images PMID:7929811

  16. Chimaeric antigen receptor T-cell therapy for tumour immunotherapy

    PubMed Central

    Sha, Huan-huan; Wang, Dan-dan; Yan, Da-li; Hu, Yong; Yang, Su-jin; Liu, Si-wen

    2017-01-01

    Chimaeric antigen receptor (CAR) T-cell therapies, as one of the cancer immunotherapies, have heralded a new era of treating cancer. The accumulating data, especially about CAR-modified T cells against CD19 support that CAR T-cell therapy is a highly effective immune therapy for B-cell malignancies. Apart from CD19, there have been many trials of CAR T cells directed other tumour specific or associated antigens (TSAs/TAAs) in haematologic malignancies and solid tumours. This review will briefly summarize basic CAR structure, parts of reported TSAs/TAAs, results of the clinical trials of CAR T-cell therapies as well as two life-threatening side effects. Experiments in vivo or in vitro, ongoing clinical trials and the outlook for CAR T-cell therapies also be included. Our future efforts will focus on identification of more viable cancer targets and more strategies to make CAR T-cell therapy safer. PMID:28053197

  17. Chimeric Antigen Receptors Modified T-Cells for Cancer Therapy.

    PubMed

    Dai, Hanren; Wang, Yao; Lu, Xuechun; Han, Weidong

    2016-07-01

    The genetic modification and characterization of T-cells with chimeric antigen receptors (CARs) allow functionally distinct T-cell subsets to recognize specific tumor cells. The incorporation of costimulatory molecules or cytokines can enable engineered T-cells to eliminate tumor cells. CARs are generated by fusing the antigen-binding region of a monoclonal antibody (mAb) or other ligand to membrane-spanning and intracellular-signaling domains. They have recently shown clinical benefit in patients treated with CD19-directed autologous T-cells. Recent successes suggest that the modification of T-cells with CARs could be a powerful approach for developing safe and effective cancer therapeutics. Here, we briefly review early studies, consider strategies to improve the therapeutic potential and safety, and discuss the challenges and future prospects for CAR T-cells in cancer therapy.

  18. Chimeric Antigen Receptors Modified T-Cells for Cancer Therapy

    PubMed Central

    Dai, Hanren; Wang, Yao; Lu, Xuechun

    2016-01-01

    The genetic modification and characterization of T-cells with chimeric antigen receptors (CARs) allow functionally distinct T-cell subsets to recognize specific tumor cells. The incorporation of costimulatory molecules or cytokines can enable engineered T-cells to eliminate tumor cells. CARs are generated by fusing the antigen-binding region of a monoclonal antibody (mAb) or other ligand to membrane-spanning and intracellular-signaling domains. They have recently shown clinical benefit in patients treated with CD19-directed autologous T-cells. Recent successes suggest that the modification of T-cells with CARs could be a powerful approach for developing safe and effective cancer therapeutics. Here, we briefly review early studies, consider strategies to improve the therapeutic potential and safety, and discuss the challenges and future prospects for CAR T-cells in cancer therapy. PMID:26819347

  19. ICOS-based chimeric antigen receptors program bipolar TH17/TH1 cells

    PubMed Central

    Chen, Xi; Madar, Aviv; Carpenito, Carmine; McGettigan, Shannon E.; Frigault, Matthew J.; Lee, Jihyun; Posey, Avery D.; Scholler, John; Scholler, Nathalie; Bonneau, Richard

    2014-01-01

    With the notable exception of B-cell malignancies, the efficacy of chimeric antigen receptor (CAR) T cells has been limited, and CAR T cells have not been shown to expand and persist in patients with nonlymphoid tumors. Here we demonstrate that redirection of primary human T cells with a CAR containing the inducible costimulator (ICOS) intracellular domain generates tumor-specific IL-17-producing effector cells that show enhanced persistence. Compared with CARs containing the CD3ζ chain alone, or in tandem with the CD28 or the 4-1BB intracellular domains, ICOS signaling increased IL-17A, IL-17F, and IL-22 following antigen recognition. In addition, T cells redirected with an ICOS-based CAR maintained a core molecular signature characteristic of TH17 cells and expressed higher levels of RORC, CD161, IL1R-1, and NCS1. Of note, ICOS signaling also induced the expression of IFN-γ and T-bet, consistent with a TH17/TH1 bipolarization. When transferred into mice with established tumors, TH17 cells that were redirected with ICOS-based CARs mediated efficient antitumor responses and showed enhanced persistence compared with CD28- or 4-1BB-based CAR T cells. Thus, redirection of TH17 cells with a CAR encoding the ICOS intracellular domain is a promising approach to augment the function and persistence of CAR T cells in hematologic malignancies. PMID:24986688

  20. ICOS-based chimeric antigen receptors program bipolar TH17/TH1 cells.

    PubMed

    Guedan, Sonia; Chen, Xi; Madar, Aviv; Carpenito, Carmine; McGettigan, Shannon E; Frigault, Matthew J; Lee, Jihyun; Posey, Avery D; Scholler, John; Scholler, Nathalie; Bonneau, Richard; June, Carl H

    2014-08-14

    With the notable exception of B-cell malignancies, the efficacy of chimeric antigen receptor (CAR) T cells has been limited, and CAR T cells have not been shown to expand and persist in patients with nonlymphoid tumors. Here we demonstrate that redirection of primary human T cells with a CAR containing the inducible costimulator (ICOS) intracellular domain generates tumor-specific IL-17-producing effector cells that show enhanced persistence. Compared with CARs containing the CD3ζ chain alone, or in tandem with the CD28 or the 4-1BB intracellular domains, ICOS signaling increased IL-17A, IL-17F, and IL-22 following antigen recognition. In addition, T cells redirected with an ICOS-based CAR maintained a core molecular signature characteristic of TH17 cells and expressed higher levels of RORC, CD161, IL1R-1, and NCS1. Of note, ICOS signaling also induced the expression of IFN-γ and T-bet, consistent with a TH17/TH1 bipolarization. When transferred into mice with established tumors, TH17 cells that were redirected with ICOS-based CARs mediated efficient antitumor responses and showed enhanced persistence compared with CD28- or 4-1BB-based CAR T cells. Thus, redirection of TH17 cells with a CAR encoding the ICOS intracellular domain is a promising approach to augment the function and persistence of CAR T cells in hematologic malignancies.

  1. TCRα-TCRβ pairing controls recognition of CD1d and directs the development of adipose NKT cells.

    PubMed

    Vieth, Joshua A; Das, Joy; Ranaivoson, Fanomezana M; Comoletti, Davide; Denzin, Lisa K; Sant'Angelo, Derek B

    2017-01-01

    The interaction between the T cell antigen receptor (TCR) expressed by natural killer T cells (NKT cells) and the antigen-presenting molecule CD1d is distinct from interactions between the TCR and major histocompatibility complex (MHC). Our molecular modeling suggested that a hydrophobic patch created after TCRα-TCRβ pairing has a role in maintaining the conformation of the NKT cell TCR. Disruption of this patch ablated recognition of CD1d by the NKT cell TCR but not interactions of the TCR with MHC. Partial disruption of the patch, while permissive to the recognition of CD1d, significantly altered NKT cell development, which resulted in the selective accumulation of adipose-tissue-resident NKT cells. These results indicate that a key component of the TCR is essential for the development of a distinct population of NKT cells.

  2. Expression of blood group antigens on red cell microvesicles.

    PubMed

    Oreskovic, R T; Dumaswala, U J; Greenwalt, T J

    1992-01-01

    The purpose of this study was to determine whether epitopes of the A, B, D, Fya, M, N, S, s, and K blood group antigens are present on microvesicle membranes shed by red cells during storage. Vesicles were isolated from outdated units of blood having and lacking the specified antigens. Diluted antisera were absorbed with fixed quantities of vesicles from red cells with the test antigen and red cells lacking that antigen (controls). The adsorbed and unadsorbed antisera were titrated and scored by using panel cells from persons known to be heterozygous for all the non-AB antigens. The mean titration scores following adsorption with the vesicles from A, B, D, M+N-, M-N+, S+s-, S-s+, and Fy(a+b-) units were appreciably lower than the control scores (0, 0, 3, 2, 2, 0, 4, and 4 vs. 19, 23, 34, 13, 12, 16, 18, and 29, respectively), which indicated the presence of these epitopes on the membrane of shed vesicles. The results following adsorption with K:1,2 vesicles were equivocal.

  3. A universal strategy for adoptive immunotherapy of cancer through use of a novel T-cell antigen receptor.

    PubMed

    Urbanska, Katarzyna; Lanitis, Evripidis; Poussin, Mathilde; Lynn, Rachel C; Gavin, Brian P; Kelderman, Sander; Yu, Jason; Scholler, Nathalie; Powell, Daniel J

    2012-04-01

    Adoptive immunotherapies composed of T cells engineered to express a chimeric antigen receptor (CAR) offer an attractive strategy for treatment of human cancer. However, CARs have a fixed antigen specificity such that only one tumor-associated antigen (TAA) can be targeted, limiting the efficacy that can be achieved because of heterogeneous TAA expression. For this reason, a more generalized and effective application of CAR therapy would benefit from the capability to produce large panels of CARs against many known TAAs. In this study, we show a novel strategy to extend the recognition specificity potential of a bioengineered lymphocyte population, allowing flexible approaches to redirect T cells against various TAAs. Our strategy employs a biotin-binding immune receptor (BBIR) composed of an extracellular-modified avidin linked to an intracellular T-cell signaling domain. BBIR T cells recognized and bound exclusively to cancer cells pretargeted with specific biotinylated molecules. The versatility afforded by BBIRs permitted sequential or simultaneous targeting of a combination of distinct antigens. Together, our findings show that a platform of universal T-cell specificity can significantly extend conventional CAR approaches, permitting the tailored generation of T cells of unlimited antigen specificity for improving the effectiveness of adoptive T-cell immunotherapies for cancer.

  4. T Cells Redirected to a Minor Histocompatibility Antigen Instruct Intratumoral TNFα Expression and Empower Adoptive Cell Therapy for Solid Tumors.

    PubMed

    Manzo, Teresa; Sturmheit, Tabea; Basso, Veronica; Petrozziello, Elisabetta; Hess Michelini, Rodrigo; Riba, Michela; Freschi, Massimo; Elia, Angela R; Grioni, Matteo; Curnis, Flavio; Protti, Maria Pia; Schumacher, Ton N; Debets, Reno; Swartz, Melody A; Corti, Angelo; Bellone, Matteo; Mondino, Anna

    2017-02-01

    Donor-derived allogeneic T cells evoke potent graft versus tumor (GVT) effects likely due to the simultaneous recognition of tumor-specific and host-restricted minor histocompatibility (H) antigens. Here we investigated whether such effects could be reproduced in autologous settings by TCR gene-engineered lymphocytes. We report that T cells redirected either to a broadly expressed Y-encoded minor H antigen or to a tumor-associated antigen, although poorly effective if individually transferred, when simultaneously administered enabled acute autochthonous tumor debulking and resulted in durable clinical remission. Y-redirected T cells proved hyporesponsive in peripheral lymphoid organs, whereas they retained effector function at the tumor site, where in synergy with tumor-redirected lymphocytes, they instructed TNFα expression, endothelial cell activation, and intratumoral T-cell infiltration. While neutralizing TNFα hindered GVT effects by the combined T-cell infusion, a single injection of picogram amounts of NGR-TNF, a tumor vessel-targeted TNFα derivative currently in phase III clinical trials, substituted for Y-redirected cells and enabled tumor debulking by tumor-redirected lymphocytes. Together, our results provide new mechanistic insights into allogeneic GVT, validate the importance of targeting the tumor and its associated stroma, and prove the potency of a novel combined approach suitable for immediate clinical implementation. Cancer Res; 77(3); 658-71. ©2016 AACR.

  5. In Vitro Generation of Antigen-Specific T Cells from Induced Pluripotent Stem Cells of Antigen-Specific T Cell Origin.

    PubMed

    Kaneko, Shin

    2016-01-01

    Induced pluripotent stem (iPS) cells derived from T lymphocyte (T-iPS cells) preserve the T cell receptor (TCR) α and β gene rearrangements identical to the original T cell clone. Re-differentiated CD8 single positive αβ T cells from the T-iPS cells exhibited antigen-specific cytotoxicity, improved proliferative response, and elongation of telomere indicating rejuvenation of antigen specific T cell immunity in vitro. To regenerate antigen specific cytotoxic T lymphocytes (CTL), first, we have optimized a method for reprogramming-resistant CD8 T cell clones into T-iPS cells by using sendaiviral vectors. Second, we have optimized stepwise differentiation methods for inducing hematopoietic progenitor cells, T cell progenitors, and functionally matured CD8 single positive CTL. These protocols provide useful in vitro tools and models both for research of antigen-specific T cell immunotherapy and for research of normal and pathological thymopoiesis.

  6. Recognition of a common mycobacterial T-cell epitope in MPB59 of Mycobacterium bovis.

    PubMed Central

    Lightbody, K A; Girvin, R M; Pollock, D A; Mackie, D P; Neill, S D; Pollock, J M

    1998-01-01

    Bovine tuberculosis, which persists as a residual level of infection in many European countries, has implications not only for the economy of farming communities but also for human health. The aim of this study was to identify a common mycobacterial antigen which was recognized in bovine tuberculosis and to characterize the response to this antigen at the epitope level. A T-cell clone, phenotype CD4+, raised from an animal experimentally infected with Mycobacterium bovis was shown to proliferate in response to a panel of sonicates derived from different mycobacterial species indicating recognition of an antigen with broad specificity. This antigen was subsequently shown to be MPB59. Recognition of MPB59 at the epitope level was determined in experimental and field cases of bovine tuberculosis using a panel of synthetic peptides (20-mers with 10-residue overlaps) incorporating the signal sequence and mature protein. The results showed that in vitro interferon-gamma was predominantly produced in response to adjacent peptides numbers 10 and 11, suggesting that the dominant epitope was contained in the overlap, correlating to residues 101-110 (YYQSGLSIVM). This epitope was recognized by 54% of tuberculous cattle of mixed breeds, which suggests that it may be genetically permissive in terms of major histocompatibility complex presentation. Sequence analysis confirmed that there were only minor differences in the amino acid composition within this region for various mycobacterial species, which could explain the common T-cell recognition described in this study. Common recognition of this epitope indicates that it would have limited potential for use as a diagnostic reagent per se but may have potential for inclusion in a subunit vaccine. PMID:9640240

  7. Molecular Pathways: Breaking the Epithelial Cancer Barrier for Chimeric Antigen Receptor and T-cell Receptor Gene Therapy.

    PubMed

    Hinrichs, Christian S

    2016-04-01

    Adoptive transfer of T cells genetically engineered to express a tumor-targeting chimeric antigen receptor (CAR) or T-cell receptor (TCR) can mediate cancer regression in some patients. CARs are synthetic single-chain proteins that use antibody domains to target cell surface antigens. TCRs are natural heterodimeric proteins that can target intracellular antigens through recognition of peptides bound to human leukocyte antigens. CARs have shown promise in B-cell malignancies and TCRs in melanoma, but neither approach has achieved clear success in an epithelial cancer. Treatment of epithelial cancers may be particularly challenging because of a paucity of target antigens expressed by carcinomas and not by important healthy tissues. In addition, epithelial cancers may be protected by inhibitory ligands and soluble factors in the tumor microenvironment. One strategy to overcome these negative regulators is to modulate expression of T-cell genes to enhance intrinsic T-cell function. Programmable nucleases, which can suppress inhibitory genes, and inducible gene expression systems, which can enhance stimulatory genes, are entering clinical testing. Other work is delineating whether control of genes for immune checkpoint receptors (e.g.,PDCD1, CTLA4) and cytokine and TCR signaling regulators (e.g.,CBLB, CISH, IL12, IL15) can increase the antitumor activity of therapeutic T cells.

  8. Utilization of a photoactivatable antigen system to examine B-cell probing termination and the B-cell receptor sorting mechanisms during B-cell activation.

    PubMed

    Wang, Jing; Tang, Shan; Wan, Zhengpeng; Gao, Yiren; Cao, Yiyun; Yi, Junyang; Si, Yanyan; Zhang, Haowen; Liu, Lei; Liu, Wanli

    2016-02-02

    Antigen binding to the B-cell receptor (BCR) induces several responses, resulting in B-cell activation, proliferation, and differentiation. However, it has been difficult to study these responses due to their dynamic, fast, and transient nature. Here, we attempted to solve this problem by developing a controllable trigger point for BCR and antigen recognition through the construction of a photoactivatable antigen, caged 4-hydroxy-3-nitrophenyl acetyl (caged-NP). This photoactivatable antigen system in combination with live cell and single molecule imaging techniques enabled us to illuminate the previously unidentified B-cell probing termination behaviors and the precise BCR sorting mechanisms during B-cell activation. B cells in contact with caged-NP exhibited probing behaviors as defined by the unceasing extension of membrane pseudopods in random directions. Further analyses showed that such probing behaviors are cell intrinsic with strict dependence on F-actin remodeling but not on tonic BCR signaling. B-cell probing behaviors were terminated within 4 s after photoactivation, suggesting that this response was sensitive and specific to BCR engagement. The termination of B-cell probing was concomitant with the accumulation response of the BCRs into the BCR microclusters. We also determined the Brownian diffusion coefficient of BCRs from the same B cells before and after BCR engagement. The analysis of temporally segregated single molecule images of both BCR and major histocompatibility complex class I (MHC-I) demonstrated that antigen binding induced trapping of BCRs into the BCR microclusters is a fundamental mechanism for B cells to acquire antigens.

  9. 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

  10. Receptor-mediated endocytosis of carcinoembryonic antigen by rat liver Kupffer cells.

    PubMed

    Toth, C A; Thomas, P; Broitman, S A; Zamcheck, N

    1985-01-01

    In vivo, carcinoembryonic antigen (CEA) is removed from the circulation by the liver Kupffer cells. Immunologically identifiable CEA is transferred from these macrophages to the hepatocytes, where degradation is completed. Circulatory clearance of CEA is specific, rapid [t1/2 = 3.7 +/- 0.9 (S.D.) min], and saturable. In vitro, Kupffer cells take up CEA by a saturable process which is time/temperature dependent and colchicine sensitive. Isolated Kupffer cells endocytose CEA with an apparent Km of 6 X 10(-8) M. There are approximately 16,000 CEA binding sites per cell. Nonspecific cross-reacting antigen (NCA), a glycoprotein structurally similar to CEA, is recognized with lower affinity by the same receptor. Endocytosis is independent of the nonreducing terminal sugars on the molecule: CEA modified by Smith degradation inhibits Kupffer cell recognition of native CEA. Since performic acid oxidized CEA also inhibits endocytosis, receptor binding is similarly independent of intact protein conformation. Isolated Kupffer cells have mannose and/or N-acetyl glucosamine receptor activity but do not internalize CEA by that mechanism. Galactose-terminated glycoproteins impede CEA and NCA clearance in vivo but not Kupffer cell endocytosis in vitro. Radiolabeled CEA released from isolated Kupffer cells following endocytosis shows no apparent molecular weight change. However, the released CEA contains species with higher isoelectric points, suggesting that perhaps the removal of sialic acid and the resulting exposure of galactose residues mediate the subsequent transfer to the hepatocyte.

  11. Shape recognition of microbial cells by colloidal cell imprints

    NASA Astrophysics Data System (ADS)

    Borovička, Josef; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2013-08-01

    We have engineered a class of colloids which can recognize the shape and size of targeted microbial cells and selectively bind to their surfaces. These imprinted colloid particles, which we called ``colloid antibodies'', were fabricated by partial fragmentation of silica shells obtained by templating the targeted microbial cells. We successfully demonstrated the shape and size recognition between such colloidal imprints and matching microbial cells. High percentage of binding events of colloidal imprints with the size matching target particles was achieved. We demonstrated selective binding of colloidal imprints to target microbial cells in a binary mixture of cells of different shapes and sizes, which also resulted in high binding selectivity. We explored the role of the electrostatic interactions between the target cells and their colloid imprints by pre-coating both of them with polyelectrolytes. Selective binding occurred predominantly in the case of opposite surface charges of the colloid cell imprint and the targeted cells. The mechanism of the recognition is based on the amplification of the surface adhesion in the case of shape and size match due to the increased contact area between the target cell and the colloidal imprint. We also tested the selective binding for colloid imprints of particles of fixed shape and varying sizes. The concept of cell recognition by colloid imprints could be used for development of colloid antibodies for shape-selective binding of microbes. Such colloid antibodies could be additionally functionalized with surface groups to enhance their binding efficiency to cells of specific shape and deliver a drug payload directly to their surface or allow them to be manipulated using external fields. They could benefit the pharmaceutical industry in developing selective antimicrobial therapies and formulations.

  12. Killer Artificial Antigen Presenting Cells (KaAPC) for Efficient In Vitro Depletion of Human Antigen-specific T Cells

    PubMed Central

    Schütz, Christian; Fleck, Martin; Schneck, Jonathan P.; Oelke, Mathias

    2014-01-01

    Current treatment of T cell mediated autoimmune diseases relies mostly on strategies of global immunosuppression, which, in the long term, is accompanied by adverse side effects such as a reduced ability to control infections or malignancies. Therefore, new approaches need to be developed that target only the disease mediating cells and leave the remaining immune system intact. Over the past decade a variety of cell based immunotherapy strategies to modulate T cell mediated immune responses have been developed. Most of these approaches rely on tolerance-inducing antigen presenting cells (APC). However, in addition to being technically difficult and cumbersome, such cell-based approaches are highly sensitive to cytotoxic T cell responses, which limits their therapeutic capacity. Here we present a protocol for the generation of non-cellular killer artificial antigen presenting cells (KaAPC), which allows for the depletion of pathologic T cells while leaving the remaining immune system untouched and functional. KaAPC is an alternative solution to cellular immunotherapy which has potential for treating autoimmune diseases and allograft rejections by regulating undesirable T cell responses in an antigen specific fashion. PMID:25145915

  13. Genomic Typing of Red Cell Antigens

    DTIC Science & Technology

    2011-09-01

    Antigen‐Matched  Red  Cells   for  Sickle   Cell   Anemia  Patients  Using  Molecular Typing to Augment Testing: Meghan Delaney, Prashant Gaur, Askale...H, Constans J, Quilici JC, Lefevre‐Witier P, Sevin J, Stevens M: Study of red blood  cell  and serum enzymes in  five  Pyrenean communities and in a...Antigen‐Matched Red  Cells  for  Sickle   Cell  Anemia Patients  Using Molecular Typing to Augment Testing: AABB (poster) 2009.  Background: Patients with  sickle

  14. A novel system of artificial antigen-presenting cells efficiently stimulates Flu peptide-specific cytotoxic T cells in vitro

    SciTech Connect

    Han, Hui; Peng, Ji-Run; Chen, Peng-Cheng; Gong, Lei; Qiao, Shi-Shi; Wang, Wen-Zhen; Cui, Zhu-Qingqing; Yu, Xin; Wei, Yu-Hua; Leng, Xi-Sheng

    2011-08-05

    Highlights: {yields} Adoptive immunotherapy depends on relevant numbers of cytolytic T lymphocytes. {yields} An ideal artificial APCs system was successfully prepared in vivo. {yields} Controlled release of IL-2 leads to much more T-cell expansion. {yields} This system is better than general cellular APCs on T-cell expansion. -- Abstract: Therapeutic numbers of antigen-specific cytotoxic T lymphocytes (CTLs) are key effectors in successful adoptive immunotherapy. However, efficient and reproducible methods to meet the qualification remain poor. To address this issue, we designed the artificial antigen-presenting cell (aAPC) system based on poly(lactic-co-glycolic acid) (PLGA). A modified emulsion method was used for the preparation of PLGA particles encapsulating interleukin-2 (IL-2). Biotinylated molecular ligands for recognition and co-stimulation of T cells were attached to the particle surface through the binding of avidin-biotin. These formed the aAPC system. The function of aAPCs in the proliferation of specific CTLs against human Flu antigen was detected by enzyme-linked immunospot assay (ELISPOT) and MTT staining methods. Finally, we successfully prepared this suitable aAPC system. The results show that IL-2 is released from aAPCs in a sustained manner over 30 days. This dramatically improves the stimulatory capacity of this system as compared to the effect of exogenous addition of cytokine. In addition, our aAPCs promote the proliferation of Flu antigen-specific CTLs more effectively than the autologous cellular APCs. Here, this aAPC platform is proved to be suitable for expansion of human antigen-specific T cells.

  15. Antigen presentation by non-immune B-cell hybridoma clones: presentation of synthetic antigenic sites reveals clones that exhibit no specificity and clones that present only one epitope

    NASA Technical Reports Server (NTRS)

    Cohly, H. H.; Morrison, D. R.; Atassi, M. Z.

    1989-01-01

    Recently, we reported the preparation and antigen-presenting properties of hybridoma B-cell clones obtained after fusing non-secreting, non-antigen presenting Balb/c 653-myeloma cells with non-immune SJL spleen cells. It was found that antigen presentation at the clonal level can be specific or non-specific, depending on the particular B-cell clone. In the present work, one specific and one general presenter B-cell clones were tested for their epitope presentation ability to SJL T-cells that were specific to lysozyme or myoglobin. B-cell clone A1G12, a general presenter which presented both lysozyme and myoglobin to their respective T-cell lines, was found to present all five myoglobin epitopes while clone A1L16, a lysozyme specific presenter presented only one of the three epitopes of lysozyme. The latter reveals a hitherto unknown submolecular specificity (to a given epitope within a protein) for antigen presenting cells at the clonal level. Therefore, the specificity of T-cell recognition does not only derive from the T-cell but may also be dependent on the epitope specificity of the antigen-presenting B-cell.

  16. Mechanism of Origin DNA Recognition and Assembly of an Initiator-Helicase Complex by SV40 Large Tumor Antigen

    PubMed Central

    Chang, Y. Paul; Xu, Meng; Machado, Ana Carolina Dantas; Yu, Xian Jessica; Rohs, Remo; Chen, Xiaojiang S.

    2013-01-01

    SUMMARY The DNA tumor virus Simian virus 40 (SV40) is a model system for studying eukaryotic replication. SV40 large tumor antigen (LTag) is the initiator/helicase that is essential for genome replication. LTag recognizes and assembles at the viral replication origin. We determined the structure of two multidomain LTag subunits bound to origin DNA. The structure reveals that the origin binding domains (OBDs) and Zn and AAA+ domains are involved in origin recognition and assembly. Notably, the OBDs recognize the origin in an unexpected manner. The histidine residues of the AAA+ domains insert into a narrow minor groove region with enhanced negative electrostatic potential. Computational analysis indicates that this region is intrinsically narrow, demonstrating the role of DNA shape readout in origin recognition. Our results provide important insights into the assembly of the LTag initiator/ helicase at the replication origin and suggest that histidine contacts with the minor groove serve as a mechanism of DNA shape readout. PMID:23545501

  17. Existence of a squamous cell carcinoma antigen-immunoglobulin complex causes a deviation between squamous cell carcinoma antigen concentrations determined using two different immunoassays: first report of squamous cell carcinoma antigen coupling with immunoglobulin A.

    PubMed

    Mori, Eriko; Kurano, Makoto; Tobita, Akiko; Shimosaka, Hironori; Yatomi, Yutaka

    2017-01-01

    Background Squamous cell carcinoma antigen is used as a tumour marker and is routinely measured in clinical laboratories. We validated two different immunoassays and found three cases in which the squamous cell carcinoma antigen concentrations deviated greatly between the two immunoassays. Here, we aimed to elucidate the mechanisms responsible for these deviations. Methods The squamous cell carcinoma antigen concentrations were determined using the ARCHITECT SCC (CLIA method) and the ST AIA-PACK SCC (FEIA method). We performed polyethylene glycol precipitation and size exclusion chromatography to assess the molecular weight and spike recovery and absorption tests to examine the presence of an autoantibody. Results Both methods exhibited good performances for the measurement of squamous cell carcinoma antigen, although a correlation test showed large differences in the squamous cell carcinoma antigen concentrations measured using the two methods in three cases. The results of polyethylene glycol treatment and size exclusion chromatography indicated the existence of a large molecular weight squamous cell carcinoma antigen in these three cases. The spike recovery tests suggested the possible presence of an autoantibody against squamous cell carcinoma antigen. Moreover, the absorption test revealed that large squamous cell carcinoma antigen complexes were formed by the association of squamous cell carcinoma antigen with IgG in two cases and with both IgG and IgA in one case. Conclusions This study describes the existence of large molecular weight squamous cell carcinoma antigen that has complexed with immunoglobulin in the serum samples. The reason for the deviations between the two immunoassays might be due to differences of their reactivities against the squamous cell carcinoma antigen immune complexes with their autoantibody. To our knowledge, this is the first report to describe the coupling of squamous cell carcinoma antigen with IgA.

  18. Large Scale Immune Profiling of Infected Humans and Goats Reveals Differential Recognition of Brucella melitensis Antigens

    PubMed Central

    Liang, Li; Leng, Diana; Burk, Chad; Nakajima-Sasaki, Rie; Kayala, Matthew A.; Atluri, Vidya L.; Pablo, Jozelyn; Unal, Berkay; Ficht, Thomas A.; Gotuzzo, Eduardo; Saito, Mayuko; Morrow, W. John W.; Liang, Xiaowu; Baldi, Pierre; Gilman, Robert H.; Vinetz, Joseph M.; Tsolis, Renée M.; Felgner, Philip L.

    2010-01-01

    Brucellosis is a widespread zoonotic disease that is also a potential agent of bioterrorism. Current serological assays to diagnose human brucellosis in clinical settings are based on detection of agglutinating anti-LPS antibodies. To better understand the universe of antibody responses that develop after B. melitensis infection, a protein microarray was fabricated containing 1,406 predicted B. melitensis proteins. The array was probed with sera from experimentally infected goats and naturally infected humans from an endemic region in Peru. The assay identified 18 antigens differentially recognized by infected and non-infected goats, and 13 serodiagnostic antigens that differentiate human patients proven to have acute brucellosis from syndromically similar patients. There were 31 cross-reactive antigens in healthy goats and 20 cross-reactive antigens in healthy humans. Only two of the serodiagnostic antigens and eight of the cross-reactive antigens overlap between humans and goats. Based on these results, a nitrocellulose line blot containing the human serodiagnostic antigens was fabricated and applied in a simple assay that validated the accuracy of the protein microarray results in the diagnosis of humans. These data demonstrate that an experimentally infected natural reservoir host produces a fundamentally different immune response than a naturally infected accidental human host. PMID:20454614

  19. Large scale immune profiling of infected humans and goats reveals differential recognition of Brucella melitensis antigens.

    PubMed

    Liang, Li; Leng, Diana; Burk, Chad; Nakajima-Sasaki, Rie; Kayala, Matthew A; Atluri, Vidya L; Pablo, Jozelyn; Unal, Berkay; Ficht, Thomas A; Gotuzzo, Eduardo; Saito, Mayuko; Morrow, W John W; Liang, Xiaowu; Baldi, Pierre; Gilman, Robert H; Vinetz, Joseph M; Tsolis, Renée M; Felgner, Philip L

    2010-05-04

    Brucellosis is a widespread zoonotic disease that is also a potential agent of bioterrorism. Current serological assays to diagnose human brucellosis in clinical settings are based on detection of agglutinating anti-LPS antibodies. To better understand the universe of antibody responses that develop after B. melitensis infection, a protein microarray was fabricated containing 1,406 predicted B. melitensis proteins. The array was probed with sera from experimentally infected goats and naturally infected humans from an endemic region in Peru. The assay identified 18 antigens differentially recognized by infected and non-infected goats, and 13 serodiagnostic antigens that differentiate human patients proven to have acute brucellosis from syndromically similar patients. There were 31 cross-reactive antigens in healthy goats and 20 cross-reactive antigens in healthy humans. Only two of the serodiagnostic antigens and eight of the cross-reactive antigens overlap between humans and goats. Based on these results, a nitrocellulose line blot containing the human serodiagnostic antigens was fabricated and applied in a simple assay that validated the accuracy of the protein microarray results in the diagnosis of humans. These data demonstrate that an experimentally infected natural reservoir host produces a fundamentally different immune response than a naturally infected accidental human host.

  20. M. tuberculosis T Cell Epitope Analysis Reveals Paucity of Antigenic Variation and Identifies Rare Variable TB Antigens.

    PubMed

    Coscolla, Mireia; Copin, Richard; Sutherland, Jayne; Gehre, Florian; de Jong, Bouke; Owolabi, Olumuiya; Mbayo, Georgetta; Giardina, Federica; Ernst, Joel D; Gagneux, Sebastien

    2015-11-11

    Pathogens that evade adaptive immunity typically exhibit antigenic variation. By contrast, it appears that although the chronic human tuberculosis (TB)-causing pathogen Mycobacterium tuberculosis needs to counter host T cell responses, its T cell epitopes are hyperconserved. Here we present an extensive analysis of the T cell epitopes of M. tuberculosis. We combined population genomics with experimental immunology to determine the number and identity of T cell epitope sequence variants in 216 phylogenetically diverse strains of M. tuberculosis. Antigen conservation is indeed a hallmark of M. tuberculosis. However, our analysis revealed a set of seven variable antigens that were immunogenic in subjects with active TB. These findings suggest that M. tuberculosis uses mechanisms other than antigenic variation to evade T cells. T cell epitopes that exhibit sequence variation may not be subject to the same evasion mechanisms, and hence vaccines that include such variable epitopes may be more efficacious.

  1. Identification of DRG-1 As a Melanoma-Associated Antigen Recognized by CD4+ Th1 Cells

    PubMed Central

    Kiniwa, Yukiko; Li, Jiang; Wang, Mingjun; Sun, Chuang; Lee, Jeffrey E.; Wang, Rong-Fu; Wang, Helen Y.

    2015-01-01

    Immunotherapy has emerged as a promising strategy for the treatment of metastatic melanoma. Clinical studies have demonstrated the feasibility of cancer immunotherapy using tumor antigens recognized by CD8+ T cells. However, the overall immune responses induced by these antigens are too weak and transient to induce tumor regression in the majority of patients who received immunization. A growing body of evidence suggests that CD4+ T helper (Th) cells play an important role in antitumor immunity. Therefore, the identification of MHC class II-restricted tumor antigens capable of stimulating CD4+ T cells may provide opportunities for developing effective cancer vaccines. To this end, we describe the identification of developmentally regulated GTP-binding protein 1 (DRG-1) as a melanoma-associated antigen recognized by HLA-DR11-restricted CD4+ Th1 cells. Epitope mapping analysis showed that the DRG1248-268 epitope of DRG-1 was required for T cell recognition. Reverse transcription-polymerase chain reaction revealed that DRG-1 was highly expressed in melanoma cell lines but not in normal tissues. DRG-1 knockdown by lentiviral-based shRNA suppressed melanoma cell proliferation and soft agar colony formation. Taken together, these data suggest that DRG-1 plays an important role in melanoma cell growth and transformation, indicating that DRG1 may represent a novel target for CD4+ T cell-mediated immunotherapy in melanoma. PMID:25993655

  2. Two distinct antigen systems in human B lymphocytes: identification of cell surface and intracellular antigens using monoclonal antibodies.

    PubMed Central

    Ishii, Y; Takami, T; Yuasa, H; Takei, T; Kikuchi, K

    1984-01-01

    Two distinct antigen systems (L26 and L27) specifically expressed in human B lymphocytes were identified using TB2-2B3 (2B3) and T3-5B3 (5B3) monoclonal antibodies, respectively. Whereas L26 antigen defined by 2B3 were rarely expressed on the surface of B cells but abundant in the cytoplasm, 127 antigens detected by 5B3 was clearly expressed on the cell surface. These two antigens appeared to be restricted in their expression to B cells, as they were found in most B cells but not other cell types including thymocytes, T cells, monocytes and granulocytes. Functional studies demonstrated that L27 was more easily lost from B cells after activation with pokeweed mitogen than was L26. Likewise, plasma cell myeloma, as well as normal plasma cells, was devoid of both L26 and L27, whereas immunoblastic sarcoma of B cell type expressed L26 but not L27. These two antigens co-existed in the same B cell lines including Epstein-Barr virus transformed B cell lines, B cell type acute lymphatic leukaemia (B-ALL) cell line, Burkitt's lymphoma cell lines and myeloma cell lines, but pre-B and common ALL cell lines were entirely negative for both L26 and L27. Immunoprecipitation studies showed that L26 consisted of at least two polypeptide chains with molecular weights of 30K and 33K daltons, which were clearly distinct from HLA-DR antigens. The antigen L27 is presently under study. Images Fig. 2 Fig. 3 PMID:6332692

  3. Responses of Bovine WC1+ γδ T Cells to Protein and Nonprotein Antigens of Mycobacterium bovis

    PubMed Central

    Welsh, Michael D.; Kennedy, Hilary E.; Smyth, Allister J.; Girvin, R. Martyn; Andersen, Peter; Pollock, John M.

    2002-01-01

    WC1+ γδ T cells of Mycobacterium bovis-infected cattle are highly responsive to M. bovis sonic extract (MBSE). In mycobacterial infections of other species, γδ T cells have been shown to respond to protein and nonprotein antigens, but the bovine WC1+ γδ T-cell antigenic targets within MBSE require further definition in terms of the dominance of protein versus nonprotein components. The present study sought to characterize the WC1+ γδ T-cell antigenic targets, together with the role of interleukin-2 (IL-2), in the context of M. bovis infection. This was achieved by testing crude and defined antigens to assess protein versus nonprotein recognition by WC1+ γδ T cells in comparison with CD4+ αβ T cells. Both cell types proliferated strongly in response to MBSE, with CD4+ T cells being the major producers of gamma interferon (IFN-γ). However, enzymatic digestion of the protein in MBSE removed its ability to stimulate CD4+ T-cell responses, whereas some WC1+ γδ T-cell proliferation remained. The most antigenic protein inducing proliferation and IFN-γ secretion in WC1+ γδ T-cell cultures was found to be ESAT-6, which is a potential novel diagnostic reagent and vaccine candidate. In addition, WC1+ γδ T-cell proliferation was observed in response to stimulation with prenyl pyrophosphate antigens (isopentenyl pyrophosphate and monomethyl phosphate). High levels of cellular activation (CD25 expression) resulted from MBSE stimulation of WC1+ γδ T cells from infected animals. A similar degree of activation was induced by IL-2 alone, but for WC1+ γδ T-cell division IL-2 was found to act only as a costimulatory signal, enhancing antigen-driven responses. Overall, the data indicate that protein antigens are important stimulators of WC1+ γδ T-cell proliferation and IFN-γ secretion in M. bovis infection, with nonprotein antigens inducing significant proliferation. These findings have important implications for diagnostic and vaccine development. PMID

  4. Reaching for far-flung antigen: How solid-core podosomes of dendritic cells transform into protrusive structures.

    PubMed

    Baranov, Maksim V; Ter Beest, Martin; van den Bogaart, Geert

    2014-10-01

    We recently identified a novel role for podosomes in antigen sampling. Podosomes are dynamic cellular structures that consist of point-like concentrations of actin surrounded by integrins and adaptor proteins such as vinculin and talin. Podosomes establish cellular contact with the extracellular matrix (ECM) and facilitate cell migration via ECM degradation. In our recent paper, we studied podosomes of human dendritic cells (DCs), major antigen presenting cells (APC) that take-up, process, and present foreign antigen to naive T-cells. We employed gelatin-impregnated porous polycarbonate filters to demonstrate that the mechanosensitive podosomes of DCs selectively localize to regions of low-physical resistance such as the filter pores. After degradation of the gelatin, podosomes increasingly protrude into the lumen of these pores. These protrusive podosome-derived structures contain several endocytic and early endosomal markers such as clathrin, Rab5, and VAMP3, and, surprisingly, also contain C-type lectins, a type of pathogen recognition receptors (PRRs). Finally, we performed functional uptake experiments to demonstrate that these PRRs facilitate uptake of antigen from the opposite side of the filter. Our data provide mechanistic insight in how dendritic cells sample for antigen across epithelial barriers for instance from the lumen of the lung and gut.

  5. Reaching for far-flung antigen: How solid-core podosomes of dendritic cells transform into protrusive structures

    PubMed Central

    Baranov, Maksim V; ter Beest, Martin; van den Bogaart, Geert

    2014-01-01

    We recently identified a novel role for podosomes in antigen sampling. Podosomes are dynamic cellular structures that consist of point-like concentrations of actin surrounded by integrins and adaptor proteins such as vinculin and talin. Podosomes establish cellular contact with the extracellular matrix (ECM) and facilitate cell migration via ECM degradation. In our recent paper, we studied podosomes of human dendritic cells (DCs), major antigen presenting cells (APC) that take-up, process, and present foreign antigen to naive T-cells. We employed gelatin-impregnated porous polycarbonate filters to demonstrate that the mechanosensitive podosomes of DCs selectively localize to regions of low-physical resistance such as the filter pores. After degradation of the gelatin, podosomes increasingly protrude into the lumen of these pores. These protrusive podosome-derived structures contain several endocytic and early endosomal markers such as clathrin, Rab5, and VAMP3, and, surprisingly, also contain C-type lectins, a type of pathogen recognition receptors (PRRs). Finally, we performed functional uptake experiments to demonstrate that these PRRs facilitate uptake of antigen from the opposite side of the filter. Our data provide mechanistic insight in how dendritic cells sample for antigen across epithelial barriers for instance from the lumen of the lung and gut. PMID:26843902

  6. Immunochemical properties of antigen-specific monkey T-cell suppressor factor induced with a Streptococcus mutans antigen.

    PubMed Central

    Lamb, J R; Zanders, E D; Kontiainen, S; Lehner, T

    1980-01-01

    Antigen-specific suppressor factor could be released from monkey suppressor T cells induced in vitro with a protein antigen isolated from the carcinogenic bacterium Streptococcus mutans. The suppressor activity was due to the factor itself and not to carryover of free antigen. Characterization of the monkey factor revealed it to have a molecular weight of ca. 70,000, and to contain a constant region and determinants encoded by the major histocompatibility complex. The presence of immunoglobulin determinants could not be demonstrated. However, by virtue of its adsorption to specific antigen, an antigen-combining site was shown to be present. The possible regulatory role of streptococcal antigen-specific suppressor factor in protection against dental caries is discussed. PMID:6164645

  7. Salmonella enterica Serovar Typhi Lipopolysaccharide O-Antigen Modification Impact on Serum Resistance and Antibody Recognition

    PubMed Central

    Heiss, Christian; Black, Ian; Donohue, Nicholas; Brown, Naj; Davies, Mark R.; Azadi, Parastoo; Baker, Stephen; Kaye, Paul M.

    2017-01-01

    ABSTRACT Salmonella enterica serovar Typhi is a human-restricted Gram-negative bacterial pathogen responsible for causing an estimated 27 million cases of typhoid fever annually, leading to 217,000 deaths, and current vaccines do not offer full protection. The O-antigen side chain of the lipopolysaccharide is an immunodominant antigen, can define host-pathogen interactions, and is under consideration as a vaccine target for some Gram-negative species. The composition of the O-antigen can be modified by the activity of glycosyltransferase (gtr) operons acquired by horizontal gene transfer. Here we investigate the role of two gtr operons that we identified in the S. Typhi genome. Strains were engineered to express specific gtr operons. Full chemical analysis of the O-antigens of these strains identified gtr-dependent glucosylation and acetylation. The glucosylated form of the O-antigen mediated enhanced survival in human serum and decreased complement binding. A single nucleotide deviation from an epigenetic phase variation signature sequence rendered the expression of this glucosylating gtr operon uniform in the population. In contrast, the expression of the acetylating gtrC gene is controlled by epigenetic phase variation. Acetylation did not affect serum survival, but phase variation can be an immune evasion mechanism, and thus, this modification may contribute to persistence in a host. In murine immunization studies, both O-antigen modifications were generally immunodominant. Our results emphasize that natural O-antigen modifications should be taken into consideration when assessing responses to vaccines, especially O-antigen-based vaccines, and that the Salmonella gtr repertoire may confound the protective efficacy of broad-ranging Salmonella lipopolysaccharide conjugate vaccines. PMID:28167670

  8. DC subset-specific induction of T cell responses upon antigen uptake via Fcγ receptors in vivo.

    PubMed

    Lehmann, Christian H K; Baranska, Anna; Heidkamp, Gordon F; Heger, Lukas; Neubert, Kirsten; Lühr, Jennifer J; Hoffmann, Alana; Reimer, Katharina C; Brückner, Christin; Beck, Simone; Seeling, Michaela; Kießling, Melissa; Soulat, Didier; Krug, Anne B; Ravetch, Jeffrey V; Leusen, Jeanette H W; Nimmerjahn, Falk; Dudziak, Diana

    2017-04-07

    Dendritic cells (DCs) are efficient antigen-presenting cells equipped with various cell surface receptors for the direct or indirect recognition of pathogenic microorganisms. Interestingly, not much is known about the specific expression pattern and function of the individual activating and inhibitory Fcγ receptors (FcγRs) on splenic DC subsets in vivo and how they contribute to the initiation of T cell responses. By targeting antigens to select activating and the inhibitory FcγR in vivo, we show that antigen uptake under steady-state conditions results in a short-term expansion of antigen-specific T cells, whereas under inflammatory conditions especially, the activating FcγRIV is able to induce superior CD4(+) and CD8(+) T cell responses. Of note, this effect was independent of FcγR intrinsic activating signaling pathways. Moreover, despite the expression of FcγRIV on both conventional splenic DC subsets, the induction of CD8(+) T cell responses was largely dependent on CD11c(+)CD8(+) DCs, whereas CD11c(+)CD8(-) DCs were critical for priming CD4(+) T cell responses.

  9. Properties of B cells and Thy-1-antigen-expressing cells infiltrating rat renal allografts

    SciTech Connect

    Leszczynski, D.; Halttunen, J.; Tiisala, S.; Ustinov, J.; Renkonen, R.; Haeyry, P. )

    1990-10-01

    We have examined (1) the frequency of B cells secreting antibodies against donor major histocompatibility complex (MHC) antigens and (2) the properties of Thy-1-antigen-expressing leukocytes in rats rejecting renal allografts. Our results show that B cells secreting antibodies are present in the inflammatory cell population at the frequency of 1:850. Among them only 1 out of 2-150 is engaged in production of antibodies directed to the graft MHC antigens, depending on the method of assay. This suggests that despite the observed significant production of nonspecific immunoglobulin in situ, only a minority of the B-cell population is specifically committed to the graft MHC antigens. This finding is concordant with the described previously low frequencies of the T cells specifically directed toward the graft MHC antigen. The role of the immunologically noncommitted cells in graft rejection is unknown. We have found that a substantial part (up to 60%) of inflammatory cells invading a rat kidney allograft express the Thy-1 antigen. This suggests that they might be immature (progenitor ) cells and, therefore, unable to respond to the graft antigens. Progenitor-like properties of these cells have been confirmed by their ability to reconstitute lethally irradiated syngeneic rat. Finally, these immature cells are of lymphoid, not of myeloid, linkage, because they do not proliferate in the presence of GM-CSF.

  10. Serine Proteases Enhance Immunogenic Antigen Presentation on Lung Cancer Cells.

    PubMed

    Peters, Haley L; Tripathi, Satyendra C; Kerros, Celine; Katayama, Hiroyuki; Garber, Haven R; St John, Lisa S; Federico, Lorenzo; Meraz, Ismail M; Roth, Jack A; Sepesi, Boris; Majidi, Mourad; Ruisaard, Kathryn; Clise-Dwyer, Karen; Roszik, Jason; Gibbons, Don L; Heymach, John V; Swisher, Stephen G; Bernatchez, Chantale; Alatrash, Gheath; Hanash, Samir; Molldrem, Jeffrey J

    2017-03-02

    Immunotherapies targeting immune checkpoints have proven efficacious in reducing the burden of lung cancer in patients; however, the antigenic targets of these reinvigorated T cells remain poorly defined. Lung cancer tumors contain tumor-associated macrophages (TAM) and neutrophils, which release the serine proteases neutrophil elastase (NE) and proteinase 3 (P3) into the tumor microenvironment. NE and P3 shape the antitumor adaptive immune response in breast cancer and melanoma. In this report, we demonstrate that lung cancer cells cross-presented the tumor-associated antigen PR1, derived from NE and P3. Additionally, NE and P3 enhanced the expression of human leukocyte antigen (HLA) class I molecules on lung cancer cells and induced unique, endogenous peptides in the immunopeptidome, as detected with mass spectrometry sequencing. Lung cancer patient tissues with high intratumoral TAMs were enriched for MHC class I genes and T-cell markers, and patients with high TAM and cytotoxic T lymphocyte (CTL) infiltration had improved overall survival. We confirmed the immunogenicity of unique, endogenous peptides with cytotoxicity assays against lung cancer cell lines, using CTLs from healthy donors that had been expanded against select peptides. Finally, CTLs specific for serine proteases-induced endogenous peptides were detected in lung cancer patients using peptide/HLA-A2 tetramers and were elevated in tumor-infiltrating lymphocytes. Thus, serine proteases in the tumor microenvironment of lung cancers promote the presentation of HLA class I immunogenic peptides that are expressed by lung cancer cells, thereby increasing the antigen repertoire that can be targeted in lung cancer. Cancer Immunol Res; 5(4); 1-11. ©2017 AACR.

  11. Mechanism of Action of Probiotic Bacteria on Intestinal and Systemic Immunities and Antigen-Presenting Cells.

    PubMed

    Fong, Fiona Long Yan; Shah, Nagendra P; Kirjavainen, Pirkka; El-Nezami, Hani

    2016-05-03

    Immunomodulation has been shown to be one of the major functions of probiotic bacteria. This review is presented to provide detailed information on the immunomodulatory properties of probiotics in various animal models and clinical practices. Probiotics can regulate helper T (Th) responses and release of cytokines in a strain-specific manner. For example, Lactobacillus rhamnosus GG can induce beneficial Th1 immunomodulatory effect in infants with cow's milk allergy and relieve intestinal inflammation in atopic children by promoting IL-10 generation. Mechanism of action of probiotics on antigen-presenting cells at gastrointestinal tract is also postulated in this review. Probiotic bacterial cells and their soluble factors may activate dendritic cells, macrophages, and to certain extent monocytes via toll-like-receptor recognition and may further provoke specific Th responses. They are speculated to elicit immunomodulatory effects on intestinal and systemic immunities.

  12. Natural killer cells, killer immunoglobulin-like receptors and human leucocyte antigen class I in disease

    PubMed Central

    Boyton, R J; Altmann, D M

    2007-01-01

    Natural killer cells constitute a potent, rapid part of the innate immune response to infection or transformation, and also generate a link to priming of adaptive immunity. Their function can encompass direct cytotoxicity as well as the release of cytokines and chemokines. In humans, a major component of natural killer (NK) cell target recognition depends mainly on the surveillance of human leucocyte antigen (HLA) class I molecules by killer immunoglobulin-like receptors (KIR). Different KIR can transmit inhibitory or activatory signals to the cell, and effector function is considered to result from the balance of these contributing signals. The regulation of NK cell responses depends on a number of variables: KIR genotype, HLA genotype, heterozygosity versus homozygosity for these, whether there is cognate recognition between the HLA and KIR products carried by an individual, clonal variation between individual NK cells in KIR expression, and the specific modulation of HLA expression by infection, transformation or peptide binding. Different HLA/KIR genotypes can impart different thresholds of activation to the NK cell repertoire and such genotypic variation has been found to confer altered risk in a number of diseases including human immunodeficiency virus (HIV) susceptibility and progression, hepatitis C virus clearance, idiopathic bronchiectasis, autoimmunity and cancer. PMID:17521317

  13. Nuclear localization of Merkel cell polyomavirus large T antigen in Merkel cell carcinoma

    SciTech Connect

    Nakamura, Tomoyuki; Sato, Yuko; Watanabe, Daisuke; Ito, Hideki; Shimonohara, Nozomi; Tsuji, Takahiro; Nakajima, Noriko; Suzuki, Yoshio; Matsuo, Koma; Nakagawa, Hidemi; Sata, Tetsutaro; Katano, Harutaka

    2010-03-15

    To clarify whether mutations in the large T gene encoded by Merkel cell polyomavirus affect the expression and function of large T antigen in Merkel cell carcinoma cases, we investigated the expression of large T antigen in vitro and in vivo. Immunohistochemistry using a rabbit polyclonal antibody revealed that large T antigen was expressed in the nuclei of Merkel cell carcinoma cells with Merkel cell polyomavirus infection. Deletion mutant analyses identified an Arg-Lys-Arg-Lys sequence (amino acids 277-280) as a nuclear localization signal in large T antigen. Sequence analyses revealed that there were no mutations in the nuclear localization signal in any of the eleven Merkel cell polyomavirus strains examined. Furthermore, stop codons were not observed in the upstream of the nuclear localization signal in any of the Merkel cell carcinoma cases examined. These data suggest that the nuclear localization signal is highly conserved and functional in Merkel cell carcinoma cases.

  14. The Extended Family of CD1d-Restricted NKT Cells: Sifting through a Mixed Bag of TCRs, Antigens, and Functions

    PubMed Central

    Macho-Fernandez, Elodie; Brigl, Manfred

    2015-01-01

    Natural killer T (NKT) cells comprise a family of specialized T cells that recognize lipid antigens presented by CD1d. Based on their T cell receptor (TCR) usage and antigen specificities, CD1d-restricted NKT cells have been divided into two main subsets: type I NKT cells that use a canonical invariant TCR α-chain and recognize α-galactosylceramide (α-GalCer), and type II NKT cells that use a more diverse αβ TCR repertoire and do not recognize α-GalCer. In addition, α-GalCer-reactive NKT cells that use non-canonical αβ TCRs and CD1d-restricted T cells that use γδ or δ/αβ TCRs have recently been identified, revealing further diversity among CD1d-restricted T cells. Importantly, in addition to their distinct antigen specificities, functional differences are beginning to emerge between the different members of the CD1d-restricted T cell family. In this review, while using type I NKT cells as comparison, we will focus on type II NKT cells and the other non-invariant CD1d-restricted T cell subsets, and discuss our current understanding of the antigens they recognize, the formation of stimulatory CD1d/antigen complexes, the modes of TCR-mediated antigen recognition, and the mechanisms and consequences of their activation that underlie their function in antimicrobial responses, anti-tumor immunity, and autoimmunity. PMID:26284062

  15. Chimeric Antigen Receptor T Cell Therapy in Hematology.

    PubMed

    Ataca, Pınar; Arslan, Önder

    2015-12-01

    It is well demonstrated that the immune system can control and eliminate cancer cells. Immune-mediated elimination of tumor cells has been discovered and is the basis of both cancer vaccines and cellular therapies including hematopoietic stem cell transplantation. Adoptive T cell transfer has been improved to be more specific and potent and to cause less off-target toxicity. Currently, there are two forms of engineered T cells being tested in clinical trials: T cell receptor (TCR) and chimeric antigen receptor (CAR) modified T cells. On 1 July 2014, the United States Food and Drug Administration granted 'breakthrough therapy' designation to anti-CD19 CAR T cell therapy. Many studies were conducted to evaluate the benefits of this exciting and potent new treatment modality. This review summarizes the history of adoptive immunotherapy, adoptive immunotherapy using CARs, the CAR manufacturing process, preclinical and clinical studies, and the effectiveness and drawbacks of this strategy.

  16. CARbodies: Human Antibodies Against Cell Surface Tumor Antigens Selected From Repertoires Displayed on T Cell Chimeric Antigen Receptors

    PubMed Central

    Alonso-Camino, Vanesa; Sánchez-Martín, David; Compte, Marta; Nuñez-Prado, Natalia; Diaz, Rosa M; Vile, Richard; Alvarez-Vallina, Luis

    2013-01-01

    A human single-chain variable fragment (scFv) antibody library was expressed on the surface of human T cells after transduction with lentiviral vectors (LVs). The repertoire was fused to a first-generation T cell receptor ζ (TCRζ)-based chimeric antigen receptor (CAR). We used this library to isolate antibodies termed CARbodies that recognize antigens expressed on the tumor cell surface in a proof-of-principle system. After three rounds of activation-selection there was a clear repertoire restriction, with the emergence dominant clones. The CARbodies were purified from bacterial cultures as soluble and active proteins. Furthermore, to validate its potential application for adoptive cell therapy, human T cells were transduced with a LV encoding a second-generation costimulatory CAR (CARv2) bearing the selected CARbodies. Transduced human primary T cells expressed significant levels of the CARbodies-based CARv2 fusion protein on the cell surface, and importantly could be specifically activated, after stimulation with tumor cells. This approach is a promising tool for the generation of antibodies fully adapted to the display format (CAR) and the selection context (cell synapse), which could extend the scope of current adoptive cell therapy strategies with CAR-redirected T cells. PMID:23695536

  17. Expression of cell surface antigens on mast cells: mast cell phenotyping.

    PubMed

    Hauswirth, Alexander W; Florian, Stefan; Schernthaner, Gerit-Holger; Krauth, Maria-Theresa; Sonneck, Karoline; Sperr, Wolfgang R; Valent, Peter

    2006-01-01

    During the past few decades, a number of functionally important cell surface antigens have been detected on human mast cells (MCs). These antigens include the stem cell factor receptor (SCFR/CD117), the high-affinity immunoglobulin E receptor, adhesion molecules, and activation-linked membrane determinants. Several of these antigens (CD2, CD25, CD35, CD88, CD203c) appear to be upregulated on MCs in patients with systemic mastocytosis and therefore are used as diagnostic markers. Quantitative measurement of these markers on MCs is thus of diagnostic value and is usually performed by multicolor-based flow cytometry techniques utilizing a PE- or APC-labeled antibody against CD117 for MCs detection. This chapter gives an overview about the methods of staining of MC in various tissues with special reference to novel diagnostic markers applied in patients with suspected systemic mastocytosis.

  18. Myelin-reactive antibodies initiate T cell-mediated CNS autoimmune disease by opsonization of endogenous antigen.

    PubMed

    Kinzel, Silke; Lehmann-Horn, Klaus; Torke, Sebastian; Häusler, Darius; Winkler, Anne; Stadelmann, Christine; Payne, Natalie; Feldmann, Linda; Saiz, Albert; Reindl, Markus; Lalive, Patrice H; Bernard, Claude C; Brück, Wolfgang; Weber, Martin S

    2016-07-01

    In the pathogenesis of central nervous system (CNS) demyelinating disorders, antigen-specific B cells are implicated to act as potent antigen-presenting cells (APC), eliciting waves of inflammatory CNS infiltration. Here, we provide the first evidence that CNS-reactive antibodies (Ab) are similarly capable of initiating an encephalitogenic immune response by targeting endogenous CNS antigen to otherwise inert myeloid APC. In a transgenic mouse model, constitutive production of Ab against myelin oligodendrocyte glycoprotein (MOG) was sufficient to promote spontaneous experimental autoimmune encephalomyelitis (EAE) in the absence of B cells, when mice endogenously contained MOG-recognizing T cells. Adoptive transfer studies corroborated that anti-MOG Ab triggered activation and expansion of peripheral MOG-specific T cells in an Fc-dependent manner, subsequently causing EAE. To evaluate the underlying mechanism, anti-MOG Ab were added to a co-culture of myeloid APC and MOG-specific T cells. At otherwise undetected concentrations, anti-MOG Ab enabled Fc-mediated APC recognition of intact MOG; internalized, processed and presented MOG activated naïve T cells to differentiate in an encephalitogenic manner. In a series of translational experiments, anti-MOG Ab from two patients with an acute flare of CNS inflammation likewise facilitated detection of human MOG. Jointly, these observations highlight Ab-mediated opsonization of endogenous CNS auto-antigen as a novel disease- and/or relapse-triggering mechanism in CNS demyelinating disorders.

  19. WI-1, a novel 120-kilodalton surface protein on Blastomyces dermatitidis yeast cells, is a target antigen of cell-mediated immunity in human blastomycosis.

    PubMed Central

    Klein, B S; Sondel, P M; Jones, J M

    1992-01-01

    A large body of experimental data has demonstrated the central role of T cells in acquired resistance to the dimorphic fungus Blastomyces dermatitidis. We examined the human T-cell response to WI-1, a 120-kDa B. dermatitidis yeast cell surface protein recently shown to be an immunodominant antigen of the B-cell response in infected humans. Peripheral blood lymphocytes from 10 blastomycosis patients studied proliferated in response to WI-1 (mean, 19,431 cpm) and to the standard, crude cell wall antigen, Blastomyces alkali- and water-soluble antigen (B-ASWS) (mean, 19,131 cpm); lymphocytes from 10 histoplasmosis patients and 10 normal control subjects did not respond to WI-1. WI-1 stimulation of patient lymphocytes and rechallenge with WI-1 or B-ASWS showed that the antigens share immunodominant epitopes. Of 100 WI-1-responsive T-cell clones derived from peripheral blood, 10 were studied in detail to assess the phenotype, function, and ligands recognized. The clones exhibit the CD3+ CD4+ phenotype of helper T cells; 2 of 10 clones (and 21% of antigen-stimulated peripheral blood lymphocytes) use the V beta 8 T-cell receptor gene element to respond to WI-1. All the clones proliferate in response to both WI-1 and B-ASWS but not other fungal antigens, and some mediate potent cytolytic effects on WI-1- and B-ASWS-labeled targets. WI-1 recognition requires antigen processing and presentation of epitopes in association with HLA-DR (to noncytolytic clones) and HLA-DP (to cytolytic clones). From these findings, we conclude that CD4+ T cells with regulatory and cytolytic properties are involved in the development of acquired resistance of B. dermatitidis, that the cells are directed against WI-1, and that the manner of display of WI-1 peptide epitopes in conjunction with major histocompatibility complex class II may influence the profile of the immune response. PMID:1383148

  20. Microfluidic squeezing for intracellular antigen loading in polyclonal B-cells as cellular vaccines

    PubMed Central

    Lee Szeto, Gregory; Van Egeren, Debra; Worku, Hermoon; Sharei, Armon; Alejandro, Brian; Park, Clara; Frew, Kirubel; Brefo, Mavis; Mao, Shirley; Heimann, Megan; Langer, Robert; Jensen, Klavs; Irvine, Darrell J

    2015-01-01

    B-cells are promising candidate autologous antigen-presenting cells (APCs) to prime antigen-specific T-cells both in vitro and in vivo. However to date, a significant barrier to utilizing B-cells as APCs is their low capacity for non-specific antigen uptake compared to “professional” APCs such as dendritic cells. Here we utilize a microfluidic device that employs many parallel channels to pass single cells through narrow constrictions in high throughput. This microscale “cell squeezing” process creates transient pores in the plasma membrane, enabling intracellular delivery of whole proteins from the surrounding medium into B-cells via mechano-poration. We demonstrate that both resting and activated B-cells process and present antigens delivered via mechano-poration exclusively to antigen-specific CD8+T-cells, and not CD4+T-cells. Squeezed B-cells primed and expanded large numbers of effector CD8+T-cells in vitro that produced effector cytokines critical to cytolytic function, including granzyme B and interferon-γ. Finally, antigen-loaded B-cells were also able to prime antigen-specific CD8+T-cells in vivo when adoptively transferred into mice. Altogether, these data demonstrate crucial proof-of-concept for mechano-poration as an enabling technology for B-cell antigen loading, priming of antigen-specific CD8+T-cells, and decoupling of antigen uptake from B-cell activation. PMID:25999171

  1. Microfluidic squeezing for intracellular antigen loading in polyclonal B-cells as cellular vaccines

    NASA Astrophysics Data System (ADS)

    Lee Szeto, Gregory; van Egeren, Debra; Worku, Hermoon; Sharei, Armon; Alejandro, Brian; Park, Clara; Frew, Kirubel; Brefo, Mavis; Mao, Shirley; Heimann, Megan; Langer, Robert; Jensen, Klavs; Irvine, Darrell J.

    2015-05-01

    B-cells are promising candidate autologous antigen-presenting cells (APCs) to prime antigen-specific T-cells both in vitro and in vivo. However to date, a significant barrier to utilizing B-cells as APCs is their low capacity for non-specific antigen uptake compared to “professional” APCs such as dendritic cells. Here we utilize a microfluidic device that employs many parallel channels to pass single cells through narrow constrictions in high throughput. This microscale “cell squeezing” process creates transient pores in the plasma membrane, enabling intracellular delivery of whole proteins from the surrounding medium into B-cells via mechano-poration. We demonstrate that both resting and activated B-cells process and present antigens delivered via mechano-poration exclusively to antigen-specific CD8+T-cells, and not CD4+T-cells. Squeezed B-cells primed and expanded large numbers of effector CD8+T-cells in vitro that produced effector cytokines critical to cytolytic function, including granzyme B and interferon-γ. Finally, antigen-loaded B-cells were also able to prime antigen-specific CD8+T-cells in vivo when adoptively transferred into mice. Altogether, these data demonstrate crucial proof-of-concept for mechano-poration as an enabling technology for B-cell antigen loading, priming of antigen-specific CD8+T-cells, and decoupling of antigen uptake from B-cell activation.

  2. Differential Recognition and Hydrolysis of Host Carbohydrate Antigens by Streptococcus pneumoniae Family 98 Glycoside Hydrolases

    SciTech Connect

    Higgins, M.; Whitworth, G; El Warry, N; Randriantsoa, M; Samain, E; Burke, R; Vocadlo, D; Boraston, A

    2009-01-01

    The presence of a fucose utilization operon in the Streptococcus pneumoniae genome and its established importance in virulence indicates a reliance of this bacterium on the harvesting of host fucose-containing glycans. The identities of these glycans, however, and how they are harvested is presently unknown. The biochemical and high resolution x-ray crystallographic analysis of two family 98 glycoside hydrolases (GH98s) from distinctive forms of the fucose utilization operon that originate from different S. pneumoniae strains reveal that one enzyme, the predominant type among pneumococcal isolates, has a unique endo-{beta}-galactosidase activity on the LewisY antigen. Altered active site topography in the other species of GH98 enzyme tune its endo-{beta}-galactosidase activity to the blood group A and B antigens. Despite their different specificities, these enzymes, and by extension all family 98 glycoside hydrolases, use an inverting catalytic mechanism. Many bacterial and viral pathogens exploit host carbohydrate antigens for adherence as a precursor to colonization or infection. However, this is the first evidence of bacterial endoglycosidase enzymes that are known to play a role in virulence and are specific for distinct host carbohydrate antigens. The strain-specific distribution of two distinct types of GH98 enzymes further suggests that S. pneumoniae strains may specialize to exploit host-specific antigens that vary from host to host, a factor that may feature in whether a strain is capable of colonizing a host or establishing an invasive infection.

  3. T-cell intracellular antigens in health and disease

    PubMed Central

    Sánchez-Jiménez, Carmen; Izquierdo, José M

    2015-01-01

    T-cell intracellular antigen 1 (TIA1) and TIA1-related/like protein (TIAR/TIAL1) are 2 proteins discovered in 1991 as components of cytotoxic T lymphocyte granules. They act in the nucleus as regulators of transcription and pre-mRNA splicing. In the cytoplasm, TIA1 and TIAR regulate and/or modulate the location, stability and/or translation of mRNAs. As knowledge of the different genes regulated by these proteins and the cellular/biological programs in which they are involved increases, it is evident that these antigens are key players in human physiology and pathology. This review will discuss the latest developments in the field, with physiopathological relevance, that point to novel roles for these regulators in the molecular and cell biology of higher eukaryotes. PMID:26036275

  4. T-cell intracellular antigens in health and disease.

    PubMed

    Sánchez-Jiménez, Carmen; Izquierdo, José M

    2015-01-01

    T-cell intracellular antigen 1 (TIA1) and TIA1-related/like protein (TIAR/TIAL1) are 2 proteins discovered in 1991 as components of cytotoxic T lymphocyte granules. They act in the nucleus as regulators of transcription and pre-mRNA splicing. In the cytoplasm, TIA1 and TIAR regulate and/or modulate the location, stability and/or translation of mRNAs. As knowledge of the different genes regulated by these proteins and the cellular/biological programs in which they are involved increases, it is evident that these antigens are key players in human physiology and pathology. This review will discuss the latest developments in the field, with physiopathological relevance, that point to novel roles for these regulators in the molecular and cell biology of higher eukaryotes.

  5. Regulatory T-cell vaccination independent of auto-antigen.

    PubMed

    Pascual, David W; Yang, Xinghong; Holderness, Kathryn; Jun, SangMu; Maddaloni, Massimo; Kochetkova, Irina

    2014-03-14

    To date, efforts to treat autoimmune diseases have primarily focused on the disease symptoms rather than on the cause of the disease. In large part, this is attributed to not knowing the responsible auto-antigens (auto-Ags) for driving the self-reactivity coupled with the poor success of treating autoimmune diseases using oral tolerance methods. Nonetheless, if tolerogenic approaches or methods that stimulate regulatory T (Treg) cells can be devised, these could subdue autoimmune diseases. To forward such efforts, our approach with colonization factor antigen I (CFA/I) fimbriae is to establish bystander immunity to ultimately drive the development of auto-Ag-specific Treg cells. Using an attenuated Salmonella vaccine expressing CFA/I fimbriae, fimbriae-specific Treg cells were induced without compromising the vaccine's capacity to protect against travelers' diarrhea or salmonellosis. By adapting the vaccine's anti-inflammatory properties, it was found that it could also dampen experimental inflammatory diseases resembling multiple sclerosis (MS) and rheumatoid arthritis. Because of this bystander effect, disease-specific Treg cells are eventually induced to resolve disease. Interestingly, this same vaccine could elicit the required Treg cell subset for each disease. For MS-like disease, conventional CD25(+) Treg cells are stimulated, but for arthritis CD39(+) Treg cells are induced instead. This review article will examine the potential of treating autoimmune diseases without having previous knowledge of the auto-Ag using an innocuous antigen to stimulate Treg cells via the production of transforming growth factor-β and interleukin-10.

  6. Chitin recognition via chitotriosidase promotes pathologic type-2 helper T cell responses to cryptococcal infection.

    PubMed

    Wiesner, Darin L; Specht, Charles A; Lee, Chrono K; Smith, Kyle D; Mukaremera, Liliane; Lee, S Thera; Lee, Chun G; Elias, Jack A; Nielsen, Judith N; Boulware, David R; Bohjanen, Paul R; Jenkins, Marc K; Levitz, Stuart M; Nielsen, Kirsten

    2015-03-01

    Pulmonary mycoses are often associated with type-2 helper T (Th2) cell responses. However, mechanisms of Th2 cell accumulation are multifactorial and incompletely known. To investigate Th2 cell responses to pulmonary fungal infection, we developed a peptide-MHCII tetramer to track antigen-specific CD4+ T cells produced in response to infection with the fungal pathogen Cryptococcus neoformans. We noted massive accruement of pathologic cryptococcal antigen-specific Th2 cells in the lungs following infection that was coordinated by lung-resident CD11b+ IRF4-dependent conventional dendritic cells. Other researchers have demonstrated that this dendritic cell subset is also capable of priming protective Th17 cell responses to another pulmonary fungal infection, Aspergillus fumigatus. Thus, higher order detection of specific features of fungal infection by these dendritic cells must direct Th2 cell lineage commitment. Since chitin-containing parasites commonly elicit Th2 responses, we hypothesized that recognition of fungal chitin is an important determinant of Th2 cell-mediated mycosis. Using C. neoformans mutants or purified chitin, we found that chitin abundance impacted Th2 cell accumulation and disease. Importantly, we determined Th2 cell induction depended on cleavage of chitin via the mammalian chitinase, chitotriosidase, an enzyme that was also prevalent in humans experiencing overt cryptococcosis. The data presented herein offers a new perspective on fungal disease susceptibility, whereby chitin recognition via chitotriosidase leads to the initiation of harmful Th2 cell differentiation by CD11b+ conventional dendritic cells in response to pulmonary fungal infection.

  7. Mature IgM-expressing plasma cells sense antigen and develop competence for cytokine production upon antigenic challenge

    PubMed Central

    Blanc, Pascal; Moro-Sibilot, Ludovic; Barthly, Lucas; Jagot, Ferdinand; This, Sébastien; de Bernard, Simon; Buffat, Laurent; Dussurgey, Sébastien; Colisson, Renaud; Hobeika, Elias; Fest, Thierry; Taillardet, Morgan; Thaunat, Olivier; Sicard, Antoine; Mondière, Paul; Genestier, Laurent; Nutt, Stephen L.; Defrance, Thierry

    2016-01-01

    Dogma holds that plasma cells, as opposed to B cells, cannot bind antigen because they have switched from expression of membrane-bound immunoglobulins (Ig) that constitute the B-cell receptor (BCR) to production of the secreted form of immunoglobulins. Here we compare the phenotypical and functional attributes of plasma cells generated by the T-cell-dependent and T-cell-independent forms of the hapten NP. We show that the nature of the secreted Ig isotype, rather than the chemical structure of the immunizing antigen, defines two functionally distinct populations of plasma cells. Fully mature IgM-expressing plasma cells resident in the bone marrow retain expression of a functional BCR, whereas their IgG+ counterparts do not. Antigen boost modifies the gene expression profile of IgM+ plasma cells and initiates a cytokine production program, characterized by upregulation of CCL5 and IL-10. Our results demonstrate that IgM-expressing plasma cells can sense antigen and acquire competence for cytokine production upon antigenic challenge. PMID:27924814

  8. Germinal center B cells recognize antigen through a specialized immune synapse architecture

    PubMed Central

    Nowosad, Carla R.; Spillane, Katelyn M.; Tolar, Pavel

    2016-01-01

    B cell activation is regulated by B cell antigen receptor (BCR) signaling and antigen internalization in immune synapses. Using large-scale imaging across B cell subsets, we show that in contrast to naive and memory B cells, which gathered antigen towards the synapse center before internalization, germinal center (GC) B cells extracted antigen by a distinct pathway using small peripheral clusters. Both naive and GC B cell synapses required proximal BCR signaling, but GC cells signaled less through the protein kinase C-β (PKC-β)–NF-κB pathway and produced stronger tugging forces on the BCR, thereby more stringently regulating antigen binding. Consequently, GC B cells extracted antigen with better affinity discrimination than naive B cells, suggesting that specialized biomechanical patterns in B cell synapses regulate T-cell dependent selection of high-affinity B cells in GCs. PMID:27183103

  9. The T cell antigen receptor: the Swiss army knife of the immune system

    PubMed Central

    Attaf, M; Legut, M; Cole, D K; Sewell, A K

    2015-01-01

    The mammalian T cell receptor (TCR) orchestrates immunity by responding to many billions of different ligands that it has never encountered before and cannot adapt to at the protein sequence level. This remarkable receptor exists in two main heterodimeric isoforms: αβ TCR and γδ TCR. The αβ TCR is expressed on the majority of peripheral T cells. Most αβ T cells recognize peptides, derived from degraded proteins, presented at the cell surface in molecular cradles called major histocompatibility complex (MHC) molecules. Recent reports have described other αβ T cell subsets. These ‘unconventional’ T cells bear TCRs that are capable of recognizing lipid ligands presented in the context of the MHC-like CD1 protein family or bacterial metabolites bound to the MHC-related protein 1 (MR1). γδ T cells constitute a minority of the T cell pool in human blood, but can represent up to half of total T cells in tissues such as the gut and skin. The identity of the preferred ligands for γδ T cells remains obscure, but it is now known that this receptor can also functionally engage CD1-lipid, or immunoglobulin (Ig) superfamily proteins called butyrophilins in the presence of pyrophosphate intermediates of bacterial lipid biosynthesis. Interactions between TCRs and these ligands allow the host to discriminate between self and non-self and co-ordinate an attack on the latter. Here, we describe how cells of the T lymphocyte lineage and their antigen receptors are generated and discuss the various modes of antigen recognition by these extraordinarily versatile receptors. PMID:25753381

  10. Multiphoton microscopy of antigen presenting cells in experimental cancer therapies

    NASA Astrophysics Data System (ADS)

    Watkins, Simon C.; Papworth, Glenn D.; Spencer, Lori A.; Larregina, Adriana T.; Hackstein, Holger

    2002-06-01

    The absence of effective conventional therapy for most cancer patients justifies the application of novel, experimental approaches. One alternative to conventional cytotoxic agents is a more defined molecular approach for cancer immune treatment; promotion of the immune system specifically to target and eliminate tumor cells on the basis of expression of tumor-associated antigens (TAA). TAA could be presented to T-cells by professional antigen-presenting cells (APC) that generate a more efficient and effective anti-tumor immune response. In fact, it has been well documented that dendritic cells, the most immunologically potent APC, are capable of recognizing, processing and presenting TAA, in turn initiating a specific antitumor immune response. Results from several laboratories and clinical trials suggested significant but still limited efficacy of TAA-pulsed dendritic cells administered to tumor-bearing hosts. Following such delivery, it is fundamentally necessary to dynamically assess cell abundance within the microenvironment of the tumor in the presence of the appropriate therapeutic agent. Multiphoton microscopy was used to assess the trafficking of pulsed dendritic cells and other APC in skin, lymph nodes and brain of several animal tumor models, following different routes of administration.

  11. Antigenic Properties and Processing Requirements of 65-Kilodalton Mannoprotein, a Major Antigen Target of Anti-Candida Human T-Cell Response, as Disclosed by Specific Human T-Cell Clones

    PubMed Central

    Nisini, Roberto; Romagnoli, Giulia; Gomez, Maria Jesus; La Valle, Roberto; Torosantucci, Antonella; Mariotti, Sabrina; Teloni, Raffaela; Cassone, Antonio

    2001-01-01

    T-cell-mediated immunity is known to play a central role in the host response to Candida albicans. T-cell clones are useful tools for the exact identification of fungal T-cell epitopes and the processing requirements of C. albicans antigens. We isolated human T-cell clones from an HLA-DRB1*1101 healthy donor by using an antigenic extract (MP-F2) of the fungus. Specific clones were T-cell receptor α/β and CD4+/CD8− and showed a T-helper type 1 cytokine profile (production of gamma interferon and not interleukin-4). The large majority of these clones recognized both the natural (highly glycosylated) and the recombinant (nonglycosylated) 65-kDa mannoprotein (MP65), an MP-F2 minor constituent that was confirmed to be an immunodominant antigen of the human T-cell response. Surprisingly, most of the clones recognized two synthetic peptides of different MP65 regions. However, the peptides shared the amino acid motif IXSXIXXL, which may be envisaged as a motif sequence representing the minimal epitope recognized by these clones. Three clones recognized natural and pronase-treated MP65 but did not detect nonglycosylated, recombinant MP65 or the peptides, suggesting a possible role for polysaccharides in T-cell recognition of C. albicans. Finally, lymphoblastoid B-cell lines were efficient antigen-presenting cells (APC) for recombinant MP65 and peptides but failed to present natural, glycosylated antigens, suggesting that nonprofessional APC might be defective in processing highly glycosylated yeast proteins. In conclusion, this study provides the first characterization of C. albicans-specific human T-cell clones and provides new clues for the definition of the cellular immune response against C. albicans. PMID:11349037

  12. Age-dependent B cell Autoimmunity to a Myelin Surface Antigen in Pediatric Multiple Sclerosis

    PubMed Central

    McLaughlin, Katherine A.; Chitnis, Tanuja; Newcombe, Jia; Franz, Bettina; Kennedy, Julia; McArdel, Shannon; Kuhle, Jens; Kappos, Ludwig; Rostasy, Kevin; Pohl, Daniela; Gagne, Donald; Ness, Jayne M.; Tenembaum, Silvia; O'Connor, Kevin C.; Viglietta, Vissia; Wong, Susan J.; Tavakoli, Norma P.; de Seze, Jerome; Khoury, Samia J.; Bar-Or, Amit; Hafler, David A.; Banwell, Brenda; Wucherpfennig, Kai W.

    2009-01-01

    Multiple sclerosis (MS) typically manifests in early to mid adulthood, but there is increasing recognition of pediatric-onset MS, aided by improvements in imaging techniques. The immunological mechanisms of disease are largely unexplored in pediatric-onset MS, in part because studies have historically focused on adult-onset disease. We investigated autoantibodies to myelin surface antigens in a large cohort of pediatric MS cases by flow cytometric labeling of transfectants that expressed different myelin proteins. While antibodies to native myelin oligodendrocyte glycoprotein (MOG) were uncommon among adult-onset patients, a subset of pediatric patients had serum antibodies that brightly labeled the MOG transfectant. Antibodies to two other myelin surface antigens were largely absent. Affinity purification of MOG antibodies as well as competition of binding with soluble MOG documented their binding specificity. The prevalence of such autoantibodies was highest among patients with a very early onset of MS: 38.7% of patients less than 10 years of age at disease onset had MOG antibodies, compared to 14.7% of patients in the 10–18 year age group. B cell autoimmunity to this myelin surface antigen is therefore most common in patients with a very early onset of MS. PMID:19687098

  13. Phenotypic and functional profiling of mouse intestinal antigen presenting cells

    PubMed Central

    Harusato, Akihito; Flannigan, Kyle L.; Geem, Duke; Denning, Timothy L.

    2015-01-01

    The microbiota that populates the mammalian intestine consists of hundreds of trillions of bacteria that are separated from underlying immune cells by a single layer of epithelial cells. The intestinal immune system effectively tolerates components of the microbiota that provide benefit to the host while remaining poised to eliminate those that are harmful. Antigen presenting cells, especially macrophages and dendritic cells, play important roles in maintaining intestinal homeostasis via their ability to orchestrate appropriate responses to the microbiota. Paramount to elucidating intestinal macrophage- and dendritic cell-mediated functions is the ability to effectively isolate and identify these cells from a complex cellular environment. In this review, we summarize methodology for the isolation and phenotypic characterization of macrophages and DCs from the mouse intestine and discuss how this may be useful for gaining insight into the mechanisms by which mucosal immune tolerance is maintained. PMID:25891794

  14. The growth of B cell receptor microcluster is a universal response of B cells encountering antigens with different motion features.

    PubMed

    Wan, Zhengpeng; Liu, Wanli

    2012-07-01

    B lymphocyte cell senses and acquires foreign antigens through clonal distributed B cell receptors (BCRs) expressed on the surface of plasma membrane. The presentation formats of antigens are quite diverse. Based on their Brownian diffusion mobility, there are three forms: free mobile soluble antigens, lateral mobile membrane bound antigens, and fixed immobile antigens. Here, using high resolution high speed live cell imaging approaches, we provide evidence that BCR microclusters are formed on the surface of B cells shortly after B cell's encountering of antigens with each format of motion features. Through high speed live cell imaging, we determine that these BCR microclusters show dynamic growth feature and by doing so function as the basic platforms for B cells to acquire the antigens. We propose that the formation and dynamic growth of BCR microcluster is a universal mechanism for B cell to response to antigens with diverse motion features.

  15. Differential recognition of members of the carcinoembryonic antigen family by Afa/Dr adhesins of diffusely adhering Escherichia coli (Afa/Dr DAEC).

    PubMed

    Berger, Cedric N; Billker, Oliver; Meyer, Thomas F; Servin, Alain L; Kansau, Imad

    2004-05-01

    Little is known about the molecular bases underlying the virulence of diffusely adhering Escherichia coli (DAEC) harbouring the Afa/Dr family of adhesins. These adhesins recognize as receptors the GPI-anchored proteins CD55 (decay-accelerating factor, DAF) and CD66e (carcinoembryonic antigen, CEA). CD66e is a member of the CEA-related cell adhesion molecules (CEACAM) family, comprising seven members. We analysed the interactions of Afa/Dr DAEC with the CEACAMs using CEACAM-expressing CHO and HeLa cells. The results demonstrate that only E. coli expressing a subfamily of Afa/Dr adhesins, named here Afa/Dr-I, including Dr, F1845 and AfaE-III adhesins, bound onto CHO cells expressing CEACAM1, CEA or CEACAM6. Whereas all the Afa/Dr adhesins elicit recruitment of CD55 around adhering bacteria, only the Afa/Dr-I subfamily elicits the recruitment of CEACAM1, CEA and CEACAM6. In addition, although CEACAM3 is not recognized as a receptor by the subfamily of Afa/Dr adhesins, it is recruited around bacteria in HeLa cells. The recruited CEACAM1, CEA and CEACAM6 around adhering bacteria resist totally or in part a detergent extraction, whereas the recruited CEACAM3 does not. Finally, the results show that recognition of CEA and CEACAM6, but not CEACAM1, is accompanied by tight attachment to bacteria of cell surface microvilli-like extensions, which are elongated. Moreover, recognition of CEA is accompanied by an activation of the Rho GTPase Cdc42 and by a phosphorylation of ERM, which in turn elicit the observed cell surface microvilli-like extensions.

  16. Cell Wall Anchoring of the Campylobacter Antigens to Lactococcus lactis

    PubMed Central

    Kobierecka, Patrycja A.; Olech, Barbara; Książek, Monika; Derlatka, Katarzyna; Adamska, Iwona; Majewski, Paweł M.; Jagusztyn-Krynicka, Elżbieta K.; Wyszyńska, Agnieszka K.

    2016-01-01

    Campylobacter jejuni is the most frequent cause of human food-borne gastroenteritis and chicken meat is the main source of infection. Recent studies showed that broiler chicken immunization against Campylobacter should be the most efficient way to lower the number of human infections by this pathogen. Induction of the mucosal immune system after oral antigen administration should provide protective immunity to chickens. In this work we tested the usefulness of Lactococcus lactis, the most extensively studied lactic acid bacterium, as a delivery vector for Campylobacter antigens. First we constructed hybrid protein – CjaA antigen presenting CjaD peptide epitopes on its surface. We showed that specific rabbit anti-rCjaAD serum reacted strongly with both CjaA and CjaD produced by a wild type C. jejuni strain. Next, rCjaAD and CjaA were fused to the C-terminus of the L. lactis YndF containing the LPTXG motif. The genes expressing these proteins were transcribed under control of the L. lactis Usp45 promoter and their products contain the Usp45 signal sequences. This strategy ensures a cell surface location of both analyzed proteins, which was confirmed by immunofluorescence assay. In order to evaluate the impact of antigen location on vaccine prototype efficacy, a L. lactis strain producing cytoplasm-located rCjaAD was also generated. Animal experiments showed a decrease of Campylobacter cecal load in vaccinated birds as compared with the control group and showed that the L. lactis harboring the surface-exposed rCjaAD antigen afforded greater protection than the L. lactis producing cytoplasm-located rCjaAD. To the best of our knowledge, this is the first attempt to employ Lactic Acid Bacteria (LAB) strains as a mucosal delivery vehicle for chicken immunization. Although the observed reduction of chicken colonization by Campylobacter resulting from vaccination was rather moderate, the experiments showed that LAB strains can be considered as an alternative vector to

  17. Immunoavtoradiographic demonstration of virus antigens in infected cells

    SciTech Connect

    Tarasishin, L.A.; Zhovnovataya, V.L.

    1986-02-01

    This paper describes a simple method of determining virus antigens, which consists essentially of the demonstration of immune complexes, formed by treatment of acetone-fixed infected cells with specific immune serum, by means of labeled protein A of S. aureus. Transplantable human HeLa cells, type 1 human adenovirus (AD 1), normal rabbit serum, and specific immune sera, obtained by immunization of rabbits with purified Ad 1 or with hexone Ad 1, and a commerical preparation of protein A of S. aureus, labeled with I 125 by the chloramine method, were used.

  18. Microbial DNA recognition by cGAS-STING and other sensors in dendritic cells in inflammatory bowel diseases.

    PubMed

    Liu, Song; Zhang, Ying; Ren, Jianan; Li, Jieshou

    2015-04-01

    Recognition of microbial nucleic acid initiates host immune defenses against pathogens. Impaired recognition of nucleic acid is involved in the pathogenesis of inflammatory bowel diseases. In contrast to the relatively well-established mechanism of microbial RNA sensing and associated signaling cascades, very little is known on how microbial DNA activates intracellular DNA sensors and controls the function of antigen-presenting cells (especially dendritic cells) to shape mucosal immune responses in intestine. In this review, we will introduce mucosal dendritic cell population, describe various putative DNA sensors, emphasize on newly identified cGAS-cGAMP-STING complex, and discuss how the detection of foreign DNA by mucosal dendritic cells activates innate and adaptive immune responses in intestine. Finally, we will identify certain inflammatory bowel disease-susceptibility genes that associate with impaired microbial DNA recognition in human.

  19. Membrane-bound heat shock proteins facilitate the uptake of dying cells and cross-presentation of cellular antigen.

    PubMed

    Zhu, Haiyan; Fang, Xiaoyun; Zhang, Dongmei; Wu, Weicheng; Shao, Miaomiao; Wang, Lan; Gu, Jianxin

    2016-01-01

    Heat shock proteins (HSPs) were originally identified as stress-responsive proteins and serve as molecular chaperones in different intracellular compartments. Translocation of HSPs to the cell surface and release of HSPs into the extracellular space have been observed during the apoptotic process and in response to a variety of cellular stress. Here, we report that UV irradiation and cisplatin treatment rapidly induce the expression of membrane-bound Hsp60, Hsp70, and Hsp90 upstream the phosphatidylserine exposure. Membrane-bound Hsp60, Hsp70 and Hsp90 could promote the release of IL-6 and IL-1β as well as DC maturation by the evaluation of CD80 and CD86 expression. On the other hand, Hsp60, Hsp70 and Hsp90 on cells could facilitate the uptake of dying cells by bone marrow-derived dendritic cells. Lectin-like oxidized LDL receptor-1 (LOX-1), as a common receptor for Hsp60, Hsp70, and Hsp90, is response for their recognition and mediates the uptake of dying cells. Furthermore, membrane-bound Hsp60, Hsp70 and Hsp90 could promote the cross-presentation of OVA antigen from E.G7 cells and inhibition of the uptake of dying cells by LOX-1 decreases the cross-presentation of cellular antigen. Therefore, the rapid exposure of HSPs on dying cells at the early stage allows for the recognition by and confers an activation signal to the immune system.

  20. Innate immune recognition of microbial cell wall components and microbial strategies to evade such recognitions.

    PubMed

    Sukhithasri, V; Nisha, N; Biswas, Lalitha; Anil Kumar, V; Biswas, Raja

    2013-08-25

    The innate immune system constitutes the first line of defence against invading microbes. The basis of this defence resides in the recognition of defined structural motifs of the microbes called "Microbial associated molecular patterns" that are absent in the host. Cell wall, the outer layer of both bacterial and fungal cells, a unique structure that is absent in the host and is recognized by the germ line encoded host receptors. Nucleotide oligomerization domain proteins, peptidoglycan recognition proteins and C-type lectins are host receptors that are involved in the recognition of bacterial cell wall (usually called peptidoglycan), whereas fungal cell wall components (N- and O-linked mannans, β-glucans etc.) are recognized by host receptors like C-type lectins (Dectin-1, Dectin-2, mannose receptor, DC-SIGN), Toll like receptors-2 and -4 (TLR-2 and TLR-4). These recognitions lead to activation of a variety of host signaling cascades and ultimate production of anti-microbial compounds including phospholipase A2, antimicrobial peptides, lysozyme, reactive oxygen and nitrogen species. These molecules act in cohort against the invading microbes to eradicate infections. Additionally pathogen recognition leads to the production of cytokines, which further activate the adaptive immune system. Both pathogenic and commensal bacteria and fungus use numerous strategies to subvert the host defence. These strategies include bacterial peptidoglycan glycan backbone modifications by O-acetylation, N-deacetylation, N-glycolylation and stem peptide modifications by amidation of meso-Diaminopimelic acid; fungal cell wall modifications by shielding the β-glucan layer with mannoproteins and α-1,3 glucan. This review focuses on the recent advances in understanding the role of bacterial and fungal cell wall in their innate immune recognition and evasion strategies.

  1. Chimeric antigen receptor engineered stem cells: a novel HIV therapy.

    PubMed

    Zhen, Anjie; Carrillo, Mayra A; Kitchen, Scott G

    2017-03-01

    Despite the success of combination antiretroviral therapy (cART) for suppressing HIV and improving patients' quality of life, HIV persists in cART-treated patients and remains an incurable disease. Financial burdens and health consequences of lifelong cART treatment call for novel HIV therapies that result in a permanent cure. Cellular immunity is central in controlling HIV replication. However, HIV adopts numerous strategies to evade immune surveillance. Engineered immunity via genetic manipulation could offer a functional cure by generating cells that have enhanced antiviral activity and are resistant to HIV infection. Recently, encouraging reports from several human clinical trials using an anti-CD19 chimeric antigen receptor (CAR) modified T-cell therapy for treating B-cell malignancies have provided valuable insights and generated remarkable enthusiasm in engineered T-cell therapy. In this review, we discuss the development of HIV-specific chimeric antigen receptors and the use of stem cell based therapies to generate lifelong anti-HIV immunity.

  2. The Role of Antigen Presenting Cells in Multiple Sclerosis

    PubMed Central

    Chastain, Emily M. L.; Duncan, D'Anne S.; Rodgers, Jane M.; Miller, Stephen D.

    2010-01-01

    Multiple Sclerosis (MS) is a debilitating T cell-mediated autoimmune disease of the central nervous system (CNS). Animal models of MS, such as experimental autoimmune encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus-Induced demyelinating disease (TMEV-IDD) have given light to cellular mechanisms involved in the initiation and progression of this organ-specific autoimmune disease. Within the CNS, antigen presenting cells (APC) such as microglia and astrocytes participate as first line defenders against infections or inflammation. However, during chronic inflammation they can participate in perpetuating the self-destructive environment by secretion of inflammatory factors and/or presentation of myelin epitopes to autoreactive T cells. Dendritic cells (DC) are also participants in the presentation of antigen to T cells, even within the CNS. While the APCs alone are not solely responsible for mediating the destruction to the myelin sheath, they are critical players in perpetuating the inflammatory milieu. This review will highlight relevant studies which have provided insight to the roles played by microglia, DCs and astrocytes in the context of CNS autoimmunity. PMID:20637861

  3. Presentation of HCV antigens to naive CD8+T cells: why the where, when, what and how are important for virus control and infection outcome.

    PubMed

    Racanelli, Vito; Manigold, Tobias

    2007-07-01

    T cell-mediated protection against HCV depends on constantly activated effector CD8(+)T cells that control emergence, spread and expansion of the virus. Why these cells fail to contain HCV replication in 70-80% of the individuals who develop persistent viremia is not clear. Although many reviews have focused on HCV's ability to interfere with the process of antigen presentation by dendritic cells (DC), only few have discussed the mechanisms whereby HCV-derived antigens become available for presentation to naive CD8(+)T cells. The importance of these mechanisms has been recently brought to light by new insight into DC biology, antigen processing, HCV replication and the immune system's functional anatomy. This review explores the different immunological scenarios in which CD8(+)T cell responses against HCV may be initiated. It describes the critical factors limiting antigen sensing and capture by APC and antigen recognition by T cells, and discusses how these factors may favor chronicity of HCV infection. Despite the lack of critical detail and hard experimental proof, this review proposes a model whereby liver seclusion, unproductive infection of professional antigen presenting cells and lack of direct tissue damage hamper the launch of a virus-specific CD8(+)T cell response. The implications for vaccine development are also discussed.

  4. Do FY antigens act as minor histocompatibility antigens in the graft-versus-host disease paradigm after human leukocyte antigen-identical sibling hematopoietic stem cell transplantation?

    PubMed

    Sellami, Mohamed Hichem; Chaabane, Manel; Kaabi, Houda; Torjemane, Lamia; Ladeb, Saloua; Ben Othmane, Tarek; Hmida, Slama

    2012-03-01

    FY antigens are candidate minor histocompatibility antigens relevant to renal allograft rejection, but no data have been reported about their role in graft-versus-host disease (GVHD) incidence after human leukocyte antigen (HLA)-identical siblings hematopoietic stem cell transplantation (HSCT). The aim of this study was to examine the effect of donor/recipient disparity at FY antigens on the incidence of GVHD in Tunisian patients receiving an HLA-identical HSCT. This work enrolled 105 Tunisian pairs of recipients and their HLA-identical sibling donors of HSCs. FY genotyping was performed with the polymerase chain reaction-sequence-specific primer method and donor/recipient disparity for these antigens was analyzed at two levels: incompatibility and nonidentity. The case-control analyses showed no significant correlation between FY disparity and the incidence of either acute or chronic GVHD. Sample size calculation showed that 572 cases and 1716 controls would be necessary to be able to detect a significant association with 80% power and two-sided type I error level of 5% (α=0.05). The lack of association in the studied cohort may be explained by the low immunogenicity of FY antigens in HSCT context, compared with other antigens such as HA-1 and CD31.

  5. Development of biohybrid immuno-selective membranes for target antigen recognition.

    PubMed

    Militano, Francesca; Poerio, Teresa; Mazzei, Rosalinda; Salerno, Simona; Bartolo, Loredana De; Giorno, Lidietta

    2017-02-03

    Membranes are gaining increasing interest in solid-phase analytical assay and biosensors applications, in particular as functional surface for bioreceptors immobilization and stabilization as well as for the concentration of target molecules in microsystems. In this work, regenerated cellulose immuno-affinity membranes were developed and they were used for the selective capture of interleukin-6 (IL-6) as targeted antigen. Protein G was covalently linked on the membrane surface and it was successfully used for the oriented site-specific antibody immobilization. The antibody binding capacity of the protein G-coupled membrane was evaluated. The specific anti IL-6 antibody was immobilized and a quantitative analysis of the amount of IL-6 captured by the immuno-affinity membrane was performed. The immobilization procedure was optimized to eliminate the non-specific binding of antigen on the membrane surface. Additionally, the interaction between anti IL-6 antibody and protein G was stabilized by chemical cross-linking with glutaraldehyde and the capture ability of immuno-affinity membranes, with and without the cross-linker, was compared. The maximum binding capacity of the protein G-coupled membrane was 43.8µg/cm(2) and the binding efficiency was 88%. The immuno-affinity membranes showed a high IL-6 capture efficiency at very low antigen concentration, up to a maximum of 91%, the amount of captured IL-6 increased linearly as increasing the initial concentration. The cross-linked surface retained the antigen binding capacity demonstrating its robustness in being reused, without antibody leakage or reduction in antibody binding capacity. The overall results demonstrated the possibility of a reliable application of the immuno-affinity membrane developed for biosensors and bioassays also in multiple use.

  6. CD94-NKG2A Recognition of Human Leukocyte Antigen (HLA)-E Bound to an HLA Class I Leader Sequence

    SciTech Connect

    Petrie,E.; Clements, C.; Lin, J.; Sullivan, L.; Johnson, D.; Huyton, T.; Heroux, A.; Hoare, H.; Beddoe, T.; et al

    2008-01-01

    The recognition of human leukocyte antigen (HLA)-E by the heterodimeric CD94-NKG2 natural killer (NK) receptor family is a central innate mechanism by which NK cells monitor the expression of other HLA molecules, yet the structural basis of this highly specific interaction is unclear. Here, we describe the crystal structure of CD94-NKG2A in complex with HLA-E bound to a peptide derived from the leader sequence of HLA-G. The CD94 subunit dominated the interaction with HLA-E, whereas the NKG2A subunit was more peripheral to the interface. Moreover, the invariant CD94 subunit dominated the peptide-mediated contacts, albeit with poor surface and chemical complementarity. This unusual binding mode was consistent with mutagenesis data at the CD94-NKG2A-HLA-E interface. There were few conformational changes in either CD94-NKG2A or HLA-E upon ligation, and such a 'lock and key' interaction is typical of innate receptor-ligand interactions. Nevertheless, the structure also provided insight into how this interaction can be modulated by subtle changes in the peptide ligand or by the pairing of CD94 with other members of the NKG2 family. Differences in the docking strategies used by the NKG2D and CD94-NKG2A receptors provided a basis for understanding the promiscuous nature of ligand recognition by NKG2D compared with the fidelity of the CD94-NKG2 receptors.

  7. Antigen exposure shapes the ratio between antigen-specific Tregs and conventional T cells in human peripheral blood

    PubMed Central

    Su, Laura F.; del Alcazar, Daniel; Stelekati, Erietta; Wherry, E. John; Davis, Mark M.

    2016-01-01

    The T-cell receptor (TCR) is required for maturation and function of regulatory T cells (Tregs), but the ligand specificities of Tregs outside the context of transgenic TCRs are largely unknown. Using peptide–MHC tetramers, we isolated rare specific Foxp3+ cells directly ex vivo from adult peripheral blood and defined their frequency and phenotype. We find that a proportion of circulating Tregs recognize foreign antigens and the frequency of these cells are similar to that of self-reactive Tregs in the absence of cognate infection. In contrast, the frequencies of Tregs that recognize some common microbial antigens are significantly reduced in the blood of most adults. Exposure to peripheral antigens likely has a major influence on the balance between Tregs and conventional T-cell subsets because a larger proportion of flu-specific T cells has a regulatory cell phenotype in the cord blood. Consistent with this finding, we show that lymphocytic choriomeningitis virus infection can directly modulate the ratio of virus-specific effectors and Tregs in mice. The resulting change in the balance within an antigen-specific T-cell population further correlates with the magnitude of effector response and the chronicity of infection. Taken together, our data highlight the importance of antigen specificity in the functional dynamics of the T-cell repertoire. Each specific population of CD4+ T cells in human peripheral blood contains a subset of Tregs at birth, but the balance between regulatory and effector subsets changes in response to peripheral antigen exposure and this could impact the robustness of antipathogen immunity. PMID:27681619

  8. Rationalization and Design of the Complementarity Determining Region Sequences in an Antibody-Antigen Recognition Interface

    PubMed Central

    Chen, Ing-Chien; Lee, Yu-Ching; Chen, Jun-Bo; Tsai, Keng-Chang; Chen, Ching-Tai; Chang, Jeng-Yih; Yang, Ei-Wen; Hsu, Po-Chiang; Jian, Jhih-Wei; Hsu, Hung-Ju; Chang, Hung-Ju; Hsu, Wen-Lian; Huang, Kai-Fa; Ma, Alex Che; Yang, An-Suei

    2012-01-01

    Protein-protein interactions are critical determinants in biological systems. Engineered proteins binding to specific areas on protein surfaces could lead to therapeutics or diagnostics for treating diseases in humans. But designing epitope-specific protein-protein interactions with computational atomistic interaction free energy remains a difficult challenge. Here we show that, with the antibody-VEGF (vascular endothelial growth factor) interaction as a model system, the experimentally observed amino acid preferences in the antibody-antigen interface can be rationalized with 3-dimensional distributions of interacting atoms derived from the database of protein structures. Machine learning models established on the rationalization can be generalized to design amino acid preferences in antibody-antigen interfaces, for which the experimental validations are tractable with current high throughput synthetic antibody display technologies. Leave-one-out cross validation on the benchmark system yielded the accuracy, precision, recall (sensitivity) and specificity of the overall binary predictions to be 0.69, 0.45, 0.63, and 0.71 respectively, and the overall Matthews correlation coefficient of the 20 amino acid types in the 24 interface CDR positions was 0.312. The structure-based computational antibody design methodology was further tested with other antibodies binding to VEGF. The results indicate that the methodology could provide alternatives to the current antibody technologies based on animal immune systems in engineering therapeutic and diagnostic antibodies against predetermined antigen epitopes. PMID:22457753

  9. Unstained viable cell recognition in phase-contrast microscopy

    NASA Astrophysics Data System (ADS)

    Skoczylas, M.; Rakowski, W.; Cherubini, R.; Gerardi, S.

    2011-09-01

    Individual cell recognition is a relevant task to be accomplished when single-ion microbeam irradiations are performed. At INFN-LNL facility cell visualization system is based on a phase-contrast optical microscope, without the use of any cell dye. Unstained cells are seeded in the special designed Petri dish, between two mylar foils, and at present the cell recognition is achieved manually by an expert operator. Nevertheless, this procedure is time consuming and sometimes it could be not practical if the amount of living cells to be irradiated is large. To reduce the time needed to recognize unstained cells on the Petri dish, it has been designed and implemented an automated, parallel algorithm. Overlapping ROIs sliding in steps over the captured grayscale image are firstly pre-classified and potential cell markers for the segmentation are obtained. Segmented objects are additionally classified to categorize cell bodies from other structures considered as sample dirt or background. As a result, cell coordinates are passed to the dedicated CELLView program that controls all the LNL single-ion microbeam irradiation protocol, including the positioning of individual cells in front of the ion beam. Unstained cell recognition system was successfully tested in experimental conditions with two different mylar surfaces. The recognition time and accuracy was acceptable, however, improvements in speed would be useful.

  10. Induction of B cell immune tolerance by antigen-modified CTL

    PubMed Central

    Nguyen, Phuong; Geiger, Terrence L.

    2010-01-01

    Background Third party-specific CTL, or veto CTL, are being assessed as a cellular therapeutic for the induction of T cell tolerance during transplantation. Conceptually, veto cell expressed antigens may induce B cell immune responses, and this may have deleterious consequences. Whether veto cells induce immunity, tolerance, or are ignored by B lymphocytes has, however, not been addressed. Methods CTL were retrovirally transduced with a model cell surface antigen to generate veto CTL. The impact of CTL-specific antigen expression on the activation and tolerization of antigen specific B cells was assessed in vitro and, using adoptive transfer models, in vivo. Results In vitro, CTL-expressed antigen induced an abortive proliferative response in specific B lymphocytes, whereby an initial proliferative burst was followed by cell death. In vivo, the administration of veto CTL also induced B cell tolerance. Specific immunoglobulin was not detected after subsequent immunization with a veto cell-expressed antigen. Modeling of this effect with antigen-specific B cell receptor (BCR) transgenic B lymphocytes demonstrated that antigen-specific B cells were eliminated by the veto CTL; cell division was accompanied by the exhaustion and depletion of responding cells. Veto-induced B cell tolerance could be wholly abrogated by treatment with the toll-like receptor ligand LPS, implying that this tolerance resulted from the absence of adequate supplemental signals during antigenic stimulation. Conclusions Veto CTL are effective promoters of B cell tolerance. Further assessment of their therapeutic potential in this regard is warranted. PMID:20065917

  11. Chimeric Antigen Receptor T Cells for Sustained Remissions in Leukemia

    PubMed Central

    Maude, Shannon L.; Frey, Noelle; Shaw, Pamela A.; Aplenc, Richard; Barrett, David M.; Bunin, Nancy J.; Chew, Anne; Gonzalez, Vanessa E.; Zheng, Zhaohui; Lacey, Simon F.; Mahnke, Yolanda D.; Melenhorst, Jan J.; Rheingold, Susan R.; Shen, Angela; Teachey, David T.; Levine, Bruce L.; June, Carl H.; Porter, David L.; Grupp, Stephan A.

    2014-01-01

    BACKGROUND Relapsed acute lymphoblastic leukemia (ALL) is difficult to treat despite the availability of aggressive therapies. Chimeric antigen receptor–modified T cells targeting CD19 may overcome many limitations of conventional therapies and induce remission in patients with refractory disease. METHODS We infused autologous T cells transduced with a CD19-directed chimeric antigen receptor (CTL019) lentiviral vector in patients with relapsed or refractory ALL at doses of 0.76×106 to 20.6×106 CTL019 cells per kilogram of body weight. Patients were monitored for a response, toxic effects, and the expansion and persistence of circulating CTL019 T cells. RESULTS A total of 30 children and adults received CTL019. Complete remission was achieved in 27 patients (90%), including 2 patients with blinatumomab-refractory disease and 15 who had undergone stem-cell transplantation. CTL019 cells proliferated in vivo and were detectable in the blood, bone marrow, and cerebrospinal fluid of patients who had a response. Sustained remission was achieved with a 6-month event-free survival rate of 67% (95% confidence interval [CI], 51 to 88) and an overall survival rate of 78% (95% CI, 65 to 95). At 6 months, the probability that a patient would have persistence of CTL019 was 68% (95% CI, 50 to 92) and the probability that a patient would have relapse-free B-cell aplasia was 73% (95% CI, 57 to 94). All the patients had the cytokine-release syndrome. Severe cytokine-release syndrome, which developed in 27% of the patients, was associated with a higher disease burden before infusion and was effectively treated with the anti–interleukin-6 receptor antibody tocilizumab. CONCLUSIONS Chimeric antigen receptor–modified T-cell therapy against CD19 was effective in treating relapsed and refractory ALL. CTL019 was associated with a high remission rate, even among patients for whom stem-cell transplantation had failed, and durable remissions up to 24 months were observed. (Funded by

  12. Functionalized Magnetic Nanoparticles for the Detection and Quantitative Analysis of Cell Surface Antigen

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Abdolahi, Mohammad; Zarkesh-Esfahani, Sayyed Hamid; Laurent, Sophie; Sermeus, Corine; Gruettner, Cordula

    2013-01-01

    Cell surface antigens as biomarkers offer tremendous potential for early diagnosis, prognosis, and therapeutic response in a variety of diseases such as cancers. In this research, a simple, rapid, accurate, inexpensive, and easily available in vitro assay based on magnetic nanoparticles and magnetic cell separation principle was applied to identify and quantitatively analyze the cell surface antigen expression in the case of prostate cancer cells. Comparing the capability of the assay with flow cytometry as a gold standard method showed similar results. The results showed that the antigen-specific magnetic cell separation with antibody-coated magnetic nanoparticles has high potential for quantitative cell surface antigen detection and analysis. PMID:23484112

  13. Inhibitory effects of thymus-independent type 2 antigens on MHC class II-restricted antigen presentation: comparative analysis of carbohydrate structures and the antigen presenting cell.

    PubMed

    González-Fernández, M; Carrasco-Marín, E; Alvarez-Domínguez, C; Outschoorn, I M; Leyva-Cobián, F

    1997-02-25

    The role of thymus-independent type 2 (TI-2) antigens (polysaccharides) on the MHC-II-restricted processing of protein antigens was studied in vitro. In general, antigen presentation is inhibited when both peritoneal and splenic macrophages (M phi) as well as Küpffer cells (KC) are preincubated with acidic polysaccharides or branched dextrans. However, the inhibitory effect of neutral polysaccharides was minimal when KC were used as antigen presenting cells (APC). Morphological evaluation of the uptake of fluoresceinated polysaccharides clearly correlates with this selective and differential interference. Polysaccharides do not block MHC-I-restricted antigen presentation. Some chemical characteristics shared by different saccharides seem to be specially related to their potential inhibitory abilities: (i) those where two anomeric carbon atoms of two interlinked sugars and (ii) those containing several sulfate groups per disaccharide repeating unit. No polysaccharide being inhibitory in M phi abrogated antigen processing in other APC: lipopolysaccharide-activated B cells, B lymphoma cells, or dendritic cells (DC). Using radiolabeled polysaccharides it was observed that DC and B cells incorporated less radioactivity as a function of time than M phi. Morphological evaluation of these different APC incubated for extended periods of time with inhibitory concentrations of polysaccharides revealed intense cytoplasmic vacuolization in M phi but not in B cells or DC. The large majority of M phi lysosomes containing polysaccharides fail to fuse with incoming endocytic vesicles and delivery of fluid-phase tracers was reduced, suggesting that indigestible carbohydrates reduced the fusion of these loaded lysosomes with endosomes containing recently internalized tracers. It is suggested that the main causes of this antigen presentation blockade are (i) the chemical characteristics of certain carbohydrates and whether the specific enzymatic machinery for their intracellular

  14. Immunoproteomic Analysis of Antibody Responses to Extracellular Proteins of Candida albicans Revealing the Importance of Glycosylation for Antigen Recognition.

    PubMed

    Luo, Ting; Krüger, Thomas; Knüpfer, Uwe; Kasper, Lydia; Wielsch, Natalie; Hube, Bernhard; Kortgen, Andreas; Bauer, Michael; Giamarellos-Bourboulis, Evangelos J; Dimopoulos, George; Brakhage, Axel A; Kniemeyer, Olaf

    2016-08-05

    During infection, the human pathogenic fungus Candida albicans undergoes a yeast-to-hypha transition, secretes numerous proteins for invasion of host tissues, and modulates the host's immune response. Little is known about the interplay of C. albicans secreted proteins and the host adaptive immune system. Here, we applied a combined 2D gel- and LC-MS/MS-based approach for the characterization of C. albicans extracellular proteins during the yeast-to-hypha transition, which led to a comprehensive C. albicans secretome map. The serological responses to C. albicans extracellular proteins were investigated by a 2D-immunoblotting approach combined with MS for protein identification. On the basis of the screening of sera from candidemia and three groups of noncandidemia patients, a core set of 19 immunodominant antibodies against secreted proteins of C. albicans was identified, seven of which represent potential diagnostic markers for candidemia (Xog1, Lip4, Asc1, Met6, Tsa1, Tpi1, and Prx1). Intriguingly, some secreted, strongly glycosylated protein antigens showed high cross-reactivity with sera from noncandidemia control groups. Enzymatic deglycosylation of proteins secreted from hyphae significantly impaired sera antibody recognition. Furthermore, deglycosylation of the recombinantly produced, secreted aspartyl protease Sap6 confirmed a significant contribution of glycan epitopes to the recognition of Sap6 by antibodies in patient's sera.

  15. Chimeric Antigen Receptor T Cells in Hematologic Malignancies.

    PubMed

    Shank, Brandon R; Do, Bryan; Sevin, Adrienne; Chen, Sheree E; Neelapu, Sattva S; Horowitz, Sandra B

    2017-03-01

    Patients with B-cell hematologic malignancies who progress through first- or second-line chemotherapy have a poor prognosis. Early clinical trials with autologous anti-CD19 chimeric antigen receptor (CAR) T cells have demonstrated promising results for patients who have relapsed or refractory disease. Lymphodepleting conditioning regimens, including cyclophosphamide, fludarabine, pentostatin, bendamustine, interleukin-2, and total body irradiation, are often administered before the infusion of CAR T cells, allowing for greater T-cell expansion. The major toxicity associated with CAR T-cell infusions is cytokine release syndrome (CRS), a potentially life-threatening systemic inflammatory disorder. The quick onset and progression of CRS require rapid detection and intervention to reduce treatment-related mortality. Management with tocilizumab can help ameliorate the symptoms of severe CRS, allowing steroids, which diminish the expansion and persistence of CAR T cells, to be reserved for tocilizumab-refractory patients. Other toxicities of CAR T-cell therapy include neutropenia and/or febrile neutropenia, infection, tumor lysis syndrome, neurotoxicity and nausea/vomiting. A review of patients' medications is imperative to eliminate medications that may contribute to treatment-related toxicities. Studies are ongoing to help optimize patient selection, preparation, safety, and management of individuals receiving CAR T cells. Long-term follow-up will help establish the place of CAR T cells in therapy.

  16. T-cell intracellular antigens function as tumor suppressor genes.

    PubMed

    Sánchez-Jiménez, C; Ludeña, M D; Izquierdo, J M

    2015-03-05

    Knockdown of T-cell intracellular antigens TIA1 and TIAR in transformed cells triggers cell proliferation and tumor growth. Using a tetracycline-inducible system, we report here that an increased expression of TIA1 or TIAR in 293 cells results in reduced rates of cell proliferation. Ectopic expression of these proteins abolish endogenous TIA1 and TIAR levels via the regulation of splicing of their pre-mRNAs, and partially represses global translation in a phospho-eukaryotic initiation factor 2 alpha-dependent manner. This is accompanied by cell cycle arrest at G1/S and cell death through caspase-dependent apoptosis and autophagy. Genome-wide profiling illustrates a selective upregulation of p53 signaling pathway-related genes. Nude mice injected with doxycycline-inducible cells expressing TIA1 or TIAR retard, or even inhibit, growth of xenotumors. Remarkably, low expressions of TIA1 and TIAR correlate with poor prognosis in patients with lung squamous cell carcinoma. These findings strongly support the concept that TIA proteins act as tumor suppressor genes.

  17. The T cell response to secreted antigens of Mycobacterium tuberculosis.

    PubMed

    Andersen, P

    1994-10-01

    Recent information from several laboratories points to proteins secreted from live Mycobacterium tuberculosis as being involved in protective immunity. We have studied protein release from M. tuberculosis during growth and have defined 3 different groups of proteins: excreted proteins, secreted proteins of the outer cell wall and cytoplasmic proteins released at late culture timepoints. These findings have lead to the definition of a short-term culture filtrate (ST-CF) enriched in excreted/secreted proteins and with a minimal content of autolytic products. ST-CF was tested as antigen in experimental vaccines against tuberculosis. A vaccine based on the adjuvant dimethyldioctadecylammonium chloride (DDA) was constructed and demonstrated to induce a potent cell mediated immune response of the Th-1 type. The vaccine was tested in parallel with a BCG standard vaccine and both vaccines induced a highly significant protection of the same magnitude. Molecules within the Ag85 complex and a 6-kDA secreted protein were mapped as the major antigenic targets for long-lived T cells involved in protective immunity against M. tuberculosis.

  18. Glycan modification of antigen alters its intracellular routing in dendritic cells, promoting priming of T cells

    PubMed Central

    Streng-Ouwehand, Ingeborg; Ho, Nataschja I; Litjens, Manja; Kalay, Hakan; Boks, Martine Annemarie; Cornelissen, Lenneke AM; Kaur Singh, Satwinder; Saeland, Eirikur; Garcia-Vallejo, Juan J; Ossendorp, Ferry A; Unger, Wendy WJ; van Kooyk, Yvette

    2016-01-01

    Antigen uptake by dendritic cells and intracellular routing of antigens to specific compartments is regulated by C-type lectin receptors that recognize glycan structures. We show that the modification of Ovalbumin (OVA) with the glycan-structure LewisX (LeX) re-directs OVA to the C-type lectin receptor MGL1. LeX-modification of OVA favored Th1 skewing of CD4+ T cells and enhanced cross-priming of CD8+ T cells. While cross-presentation of native OVA requires high antigen dose and TLR stimuli, LeX modification reduces the required amount 100-fold and obviates its dependence on TLR signaling. The OVA-LeX-induced enhancement of T cell cross-priming is MGL1-dependent as shown by reduced CD8+ effector T cell frequencies in MGL1-deficient mice. Moreover, MGL1-mediated cross-presentation of OVA-LeX neither required TAP-transporters nor Cathepsin-S and was still observed after prolonged intracellular storage of antigen in Rab11+LAMP1+ compartments. We conclude that controlled neo-glycosylation of antigens can crucially influence intracellular routing of antigens, the nature and strength of immune responses and should be considered for optimizing current vaccination strategies. DOI: http://dx.doi.org/10.7554/eLife.11765.001 PMID:26999763

  19. A Side-by-side Comparison of T cell Reactivity to Fifty-nine M. tuberculosis Antigens in Diverse Populations from five Continents

    PubMed Central

    Carpenter, Chelsea; Sidney, John; Kolla, Ravi; Nayak, Kaustuv; Tomiyama, Helena; Tomiyama, Claudia; Padilla, Oscar A.; Rozot, Virginie; Ahamed, Syed F.; Ponte, Carlos; Rolla, Valeria; Antas, Paulo R.; Chandele, Anmol; Kenneth, John; Laxmi, Seetha; Makgotlho, Edward; Vanini, Valentina; Ippolito, Giuseppe; Kazanova, Alexandra S.; Panteleev, Alexander V.; Hanekom, Willem; Mayanja-Kizza, Harriet; Lewinsohn, David; Saito, Mayuko; McElrath, M. Juliana; Boom, W. Henry; Goletti, Delia; Gilman, Robert; Lyadova, Irina V.; Scriba, Thomas J.; Kallas, Esper G.; Murali-Krishna, Kaja; Sette, Alessandro; Arlehamn, Cecilia S. Lindestam

    2015-01-01

    We compared T cell recognition of 59 prevalently recognized Mycobacterium tuberculosis (MTB) antigens in individuals latently infected with MTB (LTBI), and uninfected individuals with previous BCG vaccination, from nine locations and populations with different HLA distribution, MTB exposure rates, and standards of TB care. This comparison revealed similar response magnitudes in diverse LTBI and BCG-vaccinated cohorts and significant correlation between responses in LTBIs from the USA and other locations. Many antigens were uniformly recognized, suggesting suitability for inclusion in vaccines targeting diverse populations. Several antigens were similarly immunodominant in LTBI and BCG cohorts, suggesting applicability for vaccines aimed at boosting BCG responses. The panel of MTB antigens will be valuable for characterizing MTB-specific CD4 T cell responses irrespective of ethnicity, infecting MTB strains and BCG vaccination status. Our results illustrate how a comparative analysis can provide insight into the relative immunogenicity of existing and novel vaccine candidates in LTBIs. PMID:26277695

  20. CD8 T-cell recognition of acquired alloantigen promotes acute allograft rejection

    PubMed Central

    Harper, Simon J. F.; Ali, Jason M.; Wlodek, Elizabeth; Negus, Marg C.; Harper, Ines G.; Chhabra, Manu; Qureshi, M. Saeed; Mallik, Mekhola; Bolton, Eleanor; Bradley, J. Andrew; Pettigrew, Gavin J.

    2015-01-01

    Adaptive CD8 T-cell immunity is the principal arm of the cellular alloimmune response, but its development requires help. This can be provided by CD4 T cells that recognize alloantigen “indirectly,” as self-restricted allopeptide, but this process remains unexplained, because the target epitopes for CD4 and CD8 T-cell recognition are “unlinked” on different cells (recipient and donor antigen presenting cells (APCs), respectively). Here, we test the hypothesis that the presentation of intact and processed MHC class I alloantigen by recipient dendritic cells (DCs) (the “semidirect” pathway) allows linked help to be delivered by indirect-pathway CD4 T cells for generating destructive cytotoxic CD8 T-cell alloresponses. We show that CD8 T-cell–mediated rejection of murine heart allografts that lack hematopoietic APCs requires host secondary lymphoid tissue (SLT). SLT is necessary because within it, recipient dendritic cells can acquire MHC from graft parenchymal cells and simultaneously present it as intact protein to alloreactive CD8 T cells and as processed peptide alloantigen for recognition by indirect-pathway CD4 T cells. This enables delivery of essential help for generating cytotoxic CD8 T-cell responses that cause rapid allograft rejection. In demonstrating the functional relevance of the semidirect pathway to transplant rejection, our findings provide a solution to a long-standing conundrum as to why SLT is required for CD8 T-cell allorecognition of graft parenchymal cells and suggest a mechanism by which indirect-pathway CD4 T cells provide help for generating effector cytotoxic CD8 T-cell alloresponses at late time points after transplantation. PMID:26420874

  1. Fluorine substitutions in an antigenic peptide selectively modulate T-cell receptor binding in a minimally perturbing manner

    SciTech Connect

    Piepenbrink, Kurt H.; Borbulevych, Oleg Y.; Sommese, Ruth F.; Clemens, John; Armstrong, Kathryn M.; Desmond, Clare; Do, Priscilla; Baker, Brian M.

    2010-08-17

    TCR (T-cell receptor) recognition of antigenic peptides bound and presented by MHC (major histocompatibility complex) molecules forms the basis of the cellular immune response to pathogens and cancer. TCRs bind peptide - MHC complexes weakly and with fast kinetics, features which have hindered detailed biophysical studies of these interactions. Modified peptides resulting in enhanced TCR binding could help overcome these challenges. Furthermore, there is considerable interest in using modified peptides with enhanced TCR binding as the basis for clinical vaccines. In the present study, we examined how fluorine substitutions in an antigenic peptide can selectively impact TCR recognition. Using a structure-guided design approach, we found that fluorination of the Tax peptide [HTLV (human T-cell lymphotropic virus)-1 Tax] enhanced binding by the Tax-specific TCR A6, yet weakened binding by the Tax-specific TCR B7. The changes in affinity were consistent with crystallographic structures and fluorine chemistry, and with the A6 TCR independent of other substitutions in the interface. Peptide fluorination thus provides a means to selectively modulate TCR binding affinity without significantly perturbing peptide composition or structure. Lastly, we probed the mechanism of fluorine's effect on TCR binding and we conclude that our results were most consistent with a 'polar hydrophobicity' mechanism, rather than a purely hydrophobic- or electrostatic-based mechanism. This finding should have an impact on other attempts to alter molecular recognition with fluorine.

  2. Antibody specificity and antigen characterization of rat monoclonal antibodies against Streptococcus mutans cell wall-associated protein antigens.

    PubMed Central

    Ackermans, F; Klein, J P; Cormont, F; Bazin, H; Ogier, J A; Frank, R M; Vreven, J

    1985-01-01

    Monoclonal antibodies to Streptococcus mutans OMZ175 (serotype f) cell wall-associated antigens (wall-extracted antigens [WEA]) were derived from the fusion of Lou C plasmocytoma rat cells (IR 983 F) and spleen cells from Wistar R inbred rats immunized with WEA. Four cell lines producing monoclonal antibodies directed against a component of S. mutans WEA have been established. All four monoclonal antibodies reacted only with two antigens of WEA from S. mutans OMZ175 by Western blotting and immunoprecipitation techniques, enzyme-linked immunosorbent assay (ELISA), and competitive ELISA. Western blot analysis of WEA showed that the four monoclonal antibodies recognized two related cell wall-associated proteins with apparent molecular weights of 125,000 and 76,000. Immunoprecipitation of whole cells with the monoclonal antibodies confirmed the surface localization of the two antigens. The ELISA and competitive ELISA were used to analyze the distribution of the epitopes on seven S. mutans serotypes. All S. mutans serotypes were found to express the recognized epitopes; however, different reactivity patterns could be distinguished among the various strains tested, and the four monoclonal antibodies reacted only weakly with S. mutans serotypes d and g. Images PMID:2410364

  3. An Overview of B-1 Cells as Antigen-Presenting Cells

    PubMed Central

    Popi, Ana F.; Longo-Maugéri, Ieda M.; Mariano, Mario

    2016-01-01

    The role of B cells as antigen-presenting cells (APCs) has been extensively studied, mainly in relation to the activation of memory T cells. Considering the B cell subtypes, the role of B-1 cells as APCs is beginning to be explored. Initially, it was described that B-1 cells are activated preferentially by T-independent antigens. However, some reports demonstrated that these cells are also involved in a T-dependent response. The aim of this review is to summarize information about the ability of B-1 cells to play a role as APCs and to briefly discuss the role of the BCR and toll-like receptor signals in this process. Furthermore, some characteristics of B-1 cells, such as natural IgM production and phagocytic ability, could interfere in the participation of these cells in the onset of an adaptive response. PMID:27148259

  4. Lymphocyte imprinting with melanoma antigens acquired by trogocytosis facilitates identification of tumor-reactive T cells

    PubMed Central

    Eisenberg, Galit; Uzana, Ronny; Pato, Aviad; Frankenburg, Shoshana; Merims, Sharon; Yefenof, Eitan; Ferrone, Soldano; Peretz, Tamar; Machlenkin, Arthur; Lotem, Michal

    2013-01-01

    Trogocytosis is a contact-dependent inter-cellular transfer of membrane fragments and associated molecules from antigen presenting cells to effector lymphocytes. We previously demonstrated that trogocytosis also occurs between tumor target and cognate melanoma antigen-specific cytotoxic T cells (CTL). Here we show that, following trogocytosis, immune effector cells acquire molecular components of the tumor, including surface antigens, which are detectable by specific monoclonal antibodies. We demonstrate that CD8+ and CD4+ T cells from melanoma patients’ PBMC and tumor infiltrating lymphocytes (TIL) capture melanoma antigens, enabling identification of trogocytosing lymphocytes by staining with antigen-specific antibodies. This finding circumvents the necessity of tumor pre-labeling, which in the past was mandatory to detect membrane-capturing T cells. Through the detection of melanoma antigens on TIL, we sorted trogocytosing T cells and verified their preferential reactivity and cytotoxicity. Furthermore, tumor-antigen imprinted T cells were detected at low frequency in fresh TIL cultures shortly after extraction from the tumor. Thus, T cell imprinting by tumor antigens may allow the enrichment of melanoma antigen-specific T cells for research and potentially even for the adoptive immunotherapy of patients with cancer. PMID:23626012

  5. Identification of a potent microbial lipid antigen for diverse Natural Killer T cells1

    PubMed Central

    Wolf, Benjamin J.; Tatituri, Raju V. V.; Almeida, Catarina F.; Le Nours, Jérôme; Bhowruth, Veemal; Johnson, Darryl; Uldrich, Adam P.; Hsu, Fong-Fu; Brigl, Manfred; Besra, Gurdyal S.; Rossjohn, Jamie; Godfrey, Dale I.; Brenner, Michael B.

    2016-01-01

    Invariant Natural Killer T (iNKT) cells are a well-characterized CD1d-restricted T cell subset. The availability of potent antigens and tetramers for iNKT cells has allowed this population to be extensively studied and has revealed their central roles in infection, autoimmunity, and tumor immunity. In contrast, diverse Natural Killer T (dNKT) cells are poorly understood because the lipid antigens they recognize are largely unknown. We sought to identify dNKT cell lipid antigen(s) by interrogating a panel of dNKT mouse cell hybridomas with lipid extracts from the pathogen Listeria monocytogenes. We identified Listeria phosphatidylglycerol (PG) as a microbial antigen that was significantly more potent than a previously characterized dNKT cell antigen, mammalian PG. Further, while mammalian PG loaded CD1d tetramers did not stain dNKT cells, the Listeria-derived PG loaded tetramers did. The structure of Listeria PG was distinct from mammalian PG since it contained shorter, fully-saturated anteiso fatty acid lipid tails. CD1d binding lipid displacement studies revealed that the microbial PG antigen binds significantly better to CD1d than counterparts with the same headgroup. These data reveal a highly-potent microbial lipid antigen for a subset of dNKT cells and provide an explanation for its increased antigen potency compared to the mammalian counterpart. PMID:26254340

  6. Modes of Antigen Presentation by Lymph Node Stromal Cells and Their Immunological Implications.

    PubMed

    Hirosue, Sachiko; Dubrot, Juan

    2015-01-01

    Antigen presentation is no longer the exclusive domain of cells of hematopoietic origin. Recent works have demonstrated that lymph node stromal cell (LNSC) populations, such as fibroblastic reticular cells, lymphatic and blood endothelial cells, not only provide a scaffold for lymphocyte interactions but also exhibit active immunomodulatory roles that are critical to mounting and resolving effective immune responses. Importantly, LNSCs possess the ability to present antigens and establish antigen-specific interactions with T cells. One example is the expression of peripheral tissue antigens, which are presented on major histocompatibility complex (MHC)-I molecules with tolerogenic consequences on T cells. Additionally, exogenous antigens, including self and tumor antigens, can be processed and presented on MHC-I complexes, which result in dysfunctional activation of antigen-specific CD8(+) T cells. While MHC-I is widely expressed on cells of both hematopoietic and non-hematopoietic origins, antigen presentation via MHC-II is more precisely regulated. Nevertheless, LNSCs are capable of endogenously expressing, or alternatively, acquiring MHC-II molecules. Transfer of antigen between LNSC and dendritic cells in both directions has been recently suggested to promote tolerogenic roles of LNSCs on the CD4(+) T cell compartment. Thus, antigen presentation by LNSCs is thought to be a mechanism that promotes the maintenance of peripheral tolerance as well as generates a pool of diverse antigen-experienced T cells for protective immunity. This review aims to integrate the current and emerging literature to highlight the importance of LNSCs in immune responses, and emphasize their role in antigen trafficking, retention, and presentation.

  7. Low dose antigen promotes induction of FOXP3 in human CD4+ T cells

    PubMed Central

    Long, S. Alice; Rieck, Mary; Tatum, Megan; Bollyky, Paul L.; Wu, Rebecca P.; Muller, Isabelle; Ho, Jhon-Chun; Shilling, Heather G.; Buckner, Jane H.

    2011-01-01

    Low antigen dose promotes induction and persistence of Treg in mice, yet few studies have addressed the role of antigen dose in the induction of adaptive CD4+FOXP3+ Treg in humans. To this end, we examined the level of FOXP3 expression in human CD4+CD25− T cells upon activation with autologous antigen presenting cells and varying doses of peptide. Antigen specific T cells expressing FOXP3 were identified by flow cytometry using MHC Class II tetramer (Tmr). We found an inverse relationship between antigen dose and the frequency of FOXP3+ cells for both foreign and self antigen specific T cells. Through studies of FOXP3 locus demethylation and helios expression, we determined that variation in the frequency of Tmr+FOXP3+ T cells was not due to expansion of natural Treg, but instead, we found that induction, proliferation and persistence of FOXP3+ cells was similar in high and low dose cultures whereas proliferation of FOXP3− T cells was favored in high antigen dose cultures. The frequency of FOXP3+ cells positively correlated with suppressive function, indicative of adaptive Treg generation. The frequency of FOXP3+ cells were maintained with IL-2, but not upon re-stimulation with antigen. Together, these data suggest that low antigen dose favors the transient generation of human antigen specific adaptive Treg over the proliferation of antigen specific FOXP3- effector T cells. These adaptive Treg could function to reduce ongoing inflammatory responses and promote low dose tolerance in humans, especially when antigen exposure and tolerance is transient. PMID:21865550

  8. Dendritic cell preactivation impairs MHC class II presentation of vaccines and endogenous viral antigens

    PubMed Central

    Young, Louise J.; Wilson, Nicholas S.; Schnorrer, Petra; Mount, Adele; Lundie, Rachel J.; La Gruta, Nicole L.; Crabb, Brendan S.; Belz, Gabrielle T.; Heath, William R.; Villadangos, Jose A.

    2007-01-01

    When dendritic cells (DCs) encounter signals associated with infection or inflammation, they become activated and undergo maturation. Mature DCs are very efficient at presenting antigens captured in association with their activating signal but fail to present subsequently encountered antigens, at least in vitro. Such impairment of MHC class II (MHC II) antigen presentation has generally been thought to be a consequence of down-regulation of endocytosis, so it might be expected that antigens synthesized by the DCs themselves (for instance, viral antigens) would still be presented by mature DCs. Here, we show that DCs matured in vivo could still capture and process soluble antigens, but were unable to present peptides derived from these antigens. Furthermore, presentation of viral antigens synthesized by the DCs themselves was also severely impaired. Indeed, i.v. injection of pathogen mimics, which caused systemic DC activation in vivo, impaired the induction of CD4 T cell responses against subsequently encountered protein antigens. This immunosuppressed state could be reversed by adoptive transfer of DCs loaded exogenously with antigens, demonstrating that impairment of CD4 T cell responses was due to lack of antigen presentation rather than to overt suppression of T cell activation. The biochemical mechanism underlying this phenomenon was the down-regulation of MHC II–peptide complex formation that accompanied DC maturation. These observations have important implications for the design of prophylactic and therapeutic DC vaccines and contribute to the understanding of the mechanisms causing immunosuppression during systemic blood infections. PMID:17978177

  9. Prospects for chimeric antigen receptor (CAR) γδ T cells: A potential game changer for adoptive T cell cancer immunotherapy.

    PubMed

    Mirzaei, Hamid Reza; Mirzaei, Hamed; Lee, Sang Yun; Hadjati, Jamshid; Till, Brian G

    2016-10-01

    Excitement is growing for therapies that harness the power of patients' immune systems to combat their diseases. One approach to immunotherapy involves engineering patients' own T cells to express a chimeric antigen receptor (CAR) to treat advanced cancers, particularly those refractory to conventional therapeutic agents. Although these engineered immune cells have made remarkable strides in the treatment of patients with certain hematologic malignancies, success with solid tumors has been limited, probably due to immunosuppressive mechanisms in the tumor niche. In nearly all studies to date, T cells bearing αβ receptors have been used to generate CAR T cells. In this review, we highlight biological characteristics of γδ T cells that are distinct from those of αβ T cells, including homing to epithelial and mucosal tissues and unique functions such as direct antigen recognition, lack of alloreactivity, and ability to present antigens. We offer our perspective that these features make γδ T cells promising for use in cellular therapy against several types of solid tumors, including melanoma and gastrointestinal cancers. Engineered γδ T cells should be considered as a new platform for adoptive T cell cancer therapy for mucosal tumors.

  10. Viral Sequestration of Antigen Subverts Cross Presentation to CD8+ T Cells

    PubMed Central

    Tewalt, Eric F.; Grant, Jean M.; Granger, Erica L.; Palmer, Douglas C.; Heuss, Neal D.; Gregerson, Dale S.; Restifo, Nicholas P.; Norbury, Christopher C.

    2009-01-01

    Virus-specific CD8+ T cells (TCD8+) are initially triggered by peptide-MHC Class I complexes on the surface of professional antigen presenting cells (pAPC). Peptide-MHC complexes are produced by two spatially distinct pathways during virus infection. Endogenous antigens synthesized within virus-infected pAPC are presented via the direct-presentation pathway. Many viruses have developed strategies to subvert direct presentation. When direct presentation is blocked, the cross-presentation pathway, in which antigen is transferred from virus-infected cells to uninfected pAPC, is thought to compensate and allow the generation of effector TCD8+. Direct presentation of vaccinia virus (VACV) antigens driven by late promoters does not occur, as an abortive infection of pAPC prevents production of these late antigens. This lack of direct presentation results in a greatly diminished or ablated TCD8+ response to late antigens. We demonstrate that late poxvirus antigens do not enter the cross-presentation pathway, even when identical antigens driven by early promoters access this pathway efficiently. The mechanism mediating this novel means of viral modulation of antigen presentation involves the sequestration of late antigens within virus factories. Early antigens and cellular antigens are cross-presented from virus-infected cells, as are late antigens that are targeted to compartments outside of the virus factories. This virus-mediated blockade specifically targets the cross-presentation pathway, since late antigen that is not cross-presented efficiently enters the MHC Class II presentation pathway. These data are the first to describe an evasion mechanism employed by pathogens to prevent entry into the cross-presentation pathway. In the absence of direct presentation, this evasion mechanism leads to a complete ablation of the TCD8+ response and a potential replicative advantage for the virus. Such mechanisms of viral modulation of antigen presentation must also be taken into

  11. Chemotactic Migration of T Cells towards Dendritic Cells Promotes the Detection of Rare Antigens

    PubMed Central

    Vroomans, Renske M. A.; Marée, Athanasius F. M.; de Boer, Rob J.; Beltman, Joost B.

    2012-01-01

    In many immunological processes chemoattraction is thought to play a role in guiding cells to their sites of action. However, based on in vivo two-photon microscopy experiments in the absence of cognate antigen, T cell migration in lymph nodes (LNs) has been roughly described as a random walk. Although it has been shown that dendritic cells (DCs) carrying cognate antigen in some circumstances attract T cells chemotactically, it is currently still unclear whether chemoattraction of T cells towards DCs helps or hampers scanning. Chemoattraction towards DCs could on the one hand help T cells to rapidly find DCs. On the other hand, it could be deleterious if DCs become shielded by a multitude of attracted yet non-specific T cells. Results from a recent simulation study suggested that the deleterious effect dominates. We re-addressed the question whether T cell chemoattraction towards DCs is expected to promote or hamper the detection of rare antigens using the Cellular Potts Model, a formalism that allows for dynamic, flexible cellular shapes and cell migration. Our simulations show that chemoattraction of T cells enhances the DC scanning efficiency, leading to an increased probability that rare antigen-specific T cells find DCs carrying cognate antigen. Desensitization of T cells after contact with a DC further improves the scanning efficiency, yielding an almost threefold enhancement compared to random migration. Moreover, the chemotaxis-driven migration still roughly appears as a random walk, hence fine-tuned analysis of cell tracks will be required to detect chemotaxis within microscopy data. PMID:23166480

  12. Chemotactic migration of T cells towards dendritic cells promotes the detection of rare antigens.

    PubMed

    Vroomans, Renske M A; Marée, Athanasius F M; de Boer, Rob J; Beltman, Joost B

    2012-01-01

    In many immunological processes chemoattraction is thought to play a role in guiding cells to their sites of action. However, based on in vivo two-photon microscopy experiments in the absence of cognate antigen, T cell migration in lymph nodes (LNs) has been roughly described as a random walk. Although it has been shown that dendritic cells (DCs) carrying cognate antigen in some circumstances attract T cells chemotactically, it is currently still unclear whether chemoattraction of T cells towards DCs helps or hampers scanning. Chemoattraction towards DCs could on the one hand help T cells to rapidly find DCs. On the other hand, it could be deleterious if DCs become shielded by a multitude of attracted yet non-specific T cells. Results from a recent simulation study suggested that the deleterious effect dominates. We re-addressed the question whether T cell chemoattraction towards DCs is expected to promote or hamper the detection of rare antigens using the Cellular Potts Model, a formalism that allows for dynamic, flexible cellular shapes and cell migration. Our simulations show that chemoattraction of T cells enhances the DC scanning efficiency, leading to an increased probability that rare antigen-specific T cells find DCs carrying cognate antigen. Desensitization of T cells after contact with a DC further improves the scanning efficiency, yielding an almost threefold enhancement compared to random migration. Moreover, the chemotaxis-driven migration still roughly appears as a random walk, hence fine-tuned analysis of cell tracks will be required to detect chemotaxis within microscopy data.

  13. Downregulation of MUC1 expression and its recognition by CD8⁺ T cells on the surface of malignant pleural mesothelioma cells treated with HDACi.

    PubMed

    Roulois, David; Blanquart, Christophe; Panterne, Clarisse; Gueugnon, Fabien; Grégoire, Marc; Fonteneau, Jean-François

    2012-03-01

    Research into new treatments against malignant pleural mesothelioma (MPM) is of great interest, as this aggressive cancer is often resistant to conventional therapies. One potential strategy is the use of epigenetic drugs, such as 5-aza-2'-deoxycytidine (5-azaCdR), a DNA-hypomethylating drug, and valproate (VPA), a histone deacetylase inhibitor (HDACi). Indeed, these drugs not only trigger MPM cell death, but also induce the expression of cancer testis antigens recognized by CD8(+) T cells, such as New York-esophageal cancer-1 (NY-ESO-1). The objective of this study was to assess effects of these drugs on the expression and recognition by CD8(+) T cells of Mucin1 (MUC1), a tumor-associated antigen that is overexpressed by MPM. MPM tumor cell lines were treated with epigenetic drugs, alone or in combination. MUC1 expression by MPM cells, and its recognition by a MUC1-specific CD8(+) T-cell clone, was downregulated by HDACi when used alone or in combination with 5-azaCdR. This effect was not due to a blocking of the HLA class I presentation pathway in treated MPM cells, as NY-ESO-1 induced by 5-azaCdR alone, or with VPA, was recognized by a NY-ESO-1-specific T-cell clone. This study suggests that the choice of tumor antigens could be critical for strategies combining epigenetic drugs with immunotherapy.

  14. The cell proliferation antigen Ki-67 organises heterochromatin

    PubMed Central

    Sobecki, Michal; Mrouj, Karim; Camasses, Alain; Parisis, Nikolaos; Nicolas, Emilien; Llères, David; Gerbe, François; Prieto, Susana; Krasinska, Liliana; David, Alexandre; Eguren, Manuel; Birling, Marie-Christine; Urbach, Serge; Hem, Sonia; Déjardin, Jérôme; Malumbres, Marcos; Jay, Philippe; Dulic, Vjekoslav; Lafontaine, Denis LJ; Feil, Robert; Fisher, Daniel

    2016-01-01

    Antigen Ki-67 is a nuclear protein expressed in proliferating mammalian cells. It is widely used in cancer histopathology but its functions remain unclear. Here, we show that Ki-67 controls heterochromatin organisation. Altering Ki-67 expression levels did not significantly affect cell proliferation in vivo. Ki-67 mutant mice developed normally and cells lacking Ki-67 proliferated efficiently. Conversely, upregulation of Ki-67 expression in differentiated tissues did not prevent cell cycle arrest. Ki-67 interactors included proteins involved in nucleolar processes and chromatin regulators. Ki-67 depletion disrupted nucleologenesis but did not inhibit pre-rRNA processing. In contrast, it altered gene expression. Ki-67 silencing also had wide-ranging effects on chromatin organisation, disrupting heterochromatin compaction and long-range genomic interactions. Trimethylation of histone H3K9 and H4K20 was relocalised within the nucleus. Finally, overexpression of human or Xenopus Ki-67 induced ectopic heterochromatin formation. Altogether, our results suggest that Ki-67 expression in proliferating cells spatially organises heterochromatin, thereby controlling gene expression. DOI: http://dx.doi.org/10.7554/eLife.13722.001 PMID:26949251

  15. N-glycosylation converts non-glycoproteins into mannose receptor ligands and reveals antigen-specific T cell responses in vivo

    PubMed Central

    Kreer, Christoph; Kuepper, Janina M; Zehner, Matthias; Quast, Thomas; Kolanus, Waldemar

    2017-01-01

    N-glycosylation is generally accepted to enhance the immunogenicity of antigens because of two main reasons. First, the attachment of glycans enables recognition by endocytic receptors like the mannose receptor (MR) and hence increased uptake by dendritic cells (DCs). Second, foreign glycans are postulated to be immunostimulatory and their recognition could induce DC activation. However, a direct comparison between the immunogenicity of N-glycosylated vs. de-glycosylated proteins in vivo and a direct effect of N-glycosylated antigens on the intrinsic capacity of DCs to activate T cells have not been assessed so far. To analyze whether enforced N-glycosylation is a suited strategy to enhance the immunogenicity of non-glycosylated antigens for vaccination studies, we targeted non-glycoproteins towards the MR by introduction of artificial N-glycosylation using the methylotrophic yeast Komagataella phaffii (previously termed Pichia pastoris). We could demonstrate that the introduction of a single N-X-S/T motif was sufficient for efficient MR-binding and internalization. However, addition of N-glycosylated proteins neither influenced DC maturation nor their general capacity to activate T cells, pointing out that enforced N-glycosylation does not increase the immunogenicity of the antigen per se. Additionally, increased antigen-specific cytotoxic T cell responses in vivo after injection of N-glycosylated compared to de-glycosylated proteins were observed but this effect strongly depended on the epitope tested. A beneficial effect of N-glycosylation on antibody production could not be detected, which might be due to MR-cross-linking on DCs and to concomitant differences in IL-6 production by CD4+ T cells. These observations point out that the effect of N-glycosylation on antigen immunogenicity can vary between different antigens and therefore might have important implications for the development of vaccines using K. phaffii. PMID:28036287

  16. Immunophenotypic and antigen receptor gene rearrangement analysis in T cell neoplasia.

    PubMed Central

    Knowles, D. M.

    1989-01-01

    The author reviews the immunophenotypic profiles displayed by the major clinicopathologic categories of T cell neoplasia, the immunophenotypic criteria useful in the immunodiagnosis of T cell neoplasia, and the contributions made by antigen receptor gene rearrangement analysis to the understanding of T cell neoplasia. Neoplasms belonging to distinct clinicopathologic categories of T cell neoplasia often exhibit characteristic immunophenotypic profiles. Approximately 80% of lymphoblastic lymphomas and 20% of acute lymphoblastic leukemias express phenotypes consistent with prethymic and intrathymic stages of T cell differentiation, including intranuclear terminal deoxynucleotidyl transferase. Cutaneous T cell lymphomas of mycosis fungoides type usually express pan-T cell antigens CD2, CD5, and CD3, often lack the pan-T cell antigen CD7, and usually express the mature, peripheral helper subset phenotype, CD4+ CD8-. Cutaneous T cell lymphomas of nonmycosis fungoides type and peripheral T cell lymphomas often lack one or more pan-T cell antigens and, in addition, occasionally express the anomalous CD4+ CD8+ or CD4- CD8- phenotypes. T gamma-lymphoproliferative disease is divisable into two broad categories: those cases that are CD3 antigen positive and exhibit clonal T cell receptor beta chain (TCR-beta) gene rearrangements and those cases that are CD3 antigen negative and exhibit the TCR-beta gene germline configuration. Human T cell lymphotropic virus-I (HTLV-I) associated Japanese, Carribean, and sporadic adult T cell leukemia/lymphomas usually express pan-T cell antigens, the CD4+ CD8- phenotype, and various T cell-associated activation antigens, including the interleukin-2 receptor (CD25). Immunophenotypic criteria useful in the immunodiagnosis of T cell neoplasia include, in increasing order of utility, T cell predominance, T cell subset antigen restriction, anomalous T cell subset antigen expression, and deletion of one or more pan-T cell antigens. Only in

  17. The Other Function: Class II-Restricted Antigen Presentation by B Cells

    PubMed Central

    Adler, Lital N.; Jiang, Wei; Bhamidipati, Kartik; Millican, Matthew; Macaubas, Claudia; Hung, Shu-chen; Mellins, Elizabeth D.

    2017-01-01

    Mature B lymphocytes (B cells) recognize antigens using their B cell receptor (BCR) and are activated to become antibody-producing cells. In addition, and integral to the development of a high-affinity antibodies, B cells utilize the specialized major histocompatibility complex class II (MHCII) antigen presentation pathway to process BCR-bound and internalized protein antigens and present selected peptides in complex with MHCII to CD4+ T cells. This interaction influences the fate of both types of lymphocytes and shapes immune outcomes. Specific, effective, and optimally timed antigen presentation by B cells requires well-controlled intracellular machinery, often regulated by the combined effects of several molecular events. Here, we delineate and summarize these events in four steps along the antigen presentation pathway: (1) antigen capture and uptake by B cells; (2) intersection of internalized antigen/BCRs complexes with MHCII in peptide-loading compartments; (3) generation and regulation of MHCII/peptide complexes; and (4) exocytic transport for presentation of MHCII/peptide complexes at the surface of B cells. Finally, we discuss modulation of the MHCII presentation pathway across B cell development and maturation to effector cells, with an emphasis on the shaping of the MHCII/peptide repertoire by two key antigen presentation regulators in B cells: HLA-DM and HLA-DO. PMID:28386257

  18. Macrophage pattern recognition receptors in immunity, homeostasis and self tolerance.

    PubMed

    Mukhopadhyay, Subhankar; Plüddemann, Annette; Gordon, Siamon

    2009-01-01

    Macrophages, a major component of innate immune defence, express a large repertoire of different classes of pattern recognition receptors and other surface antigens which determine the immunologic and homeostatic potential of these versatile cells. In the light of present knowledge ofmacrophage surface antigens, we discuss self versus nonself recognition, microbicidal effector functions and self tolerance in the innate immune system.

  19. Chronological recognition by chicken of antigenic polypeptides in Salmonella enteritidis with different plasmid profiles: relationship to infection rate.

    PubMed

    Barbour, E K; El Jurdi, L H; Faroo, O M; Daghir, N J; Bouljihad, M

    2000-06-01

    The antigenic polypeptides in Salmonella Enteritidis (SE) were chronologically recognized by the chicken immune system, using Western immunoblotting. Broiler chicks challenged at three days of age with SE strain carrying the most prevalent plasmid profile of 14.1 and about (approximately) 50 kb were bled at 17, 24, 31, 38 and 45 days of age. Pooled sera of blood collected at each age was reacted by Western immunoblotting with banded polypeptides of three predominant SE strains that acquired the following respective plasmid profiles: 14.1 kb; 14.1 and approximately 50.0 kb; and 1.8, 14.1 and approximately 50.0 kb. The immunoblots of each pooled sera collected at a specific age against the three SE strains were similar. More specifically, the early immune response at 17 days of age had antibodies recognizing only one polypeptide in the three SE strains namely, the 35.8 kDa. At 24 or 31 days of age, the acquired immunity to infection had antibodies recognizing five similar polypeptides in the three SE strains namely, the 14.4 (fimbriae protein), 21.5 (fimbriae protein), 30.5, 35.8, and 66.2 kDa. At 38 and 45 days of age, the antibodies recognized additional polypeptides namely, the 41.5 and 55.6 kDa, respectively. The recognition of the 41.5 and 55.6 kDa polypeptides at 45 days of age was associated with higher invasiveness of SE to spleens and livers (15.6%) and in higher cecal colonization (59.4%) in comparison to absence of recognition to the two polypeptides at 31 days of age associated with low infectivity to spleens (0%), livers (3.1%), and ceca (9.4%).

  20. Antibody recognition in multiple sclerosis and Rett syndrome using a collection of linear and cyclic N-glucosylated antigenic probes.

    PubMed

    Real Fernández, Feliciana; Di Pisa, Margherita; Rossi, Giada; Auberger, Nicolas; Lequin, Olivier; Larregola, Maud; Benchohra, Amina; Mansuy, Christelle; Chassaing, Gerard; Lolli, Francesco; Hayek, Joussef; Lavielle, Solange; Rovero, Paolo; Mallet, Jean-Maurice; Papini, Anna Maria

    2015-09-01

    Antibody detection in autoimmune disorders, such as multiple sclerosis (MS) and Rett syndrome (RTT) can be achieved more efficiently using synthetic peptides. The previously developed synthetic antigenic probe CSF114(Glc), a type I' β-turn N-glucosylated peptide structure, is able to recognize antibodies in MS and RTT patients' sera as a sign of immune system derangement. We report herein the design, synthesis, conformational analysis, and immunological evaluation of a collection of glycopeptide analogs of CSF114(Glc) to characterize the specific role of secondary structures in MS and RTT antibody recognition. Therefore, we synthesized a series of linear and cyclic short glucosylated sequences, mimicking different β-turn conformations, which were evaluated in inhibition enzyme-linked immunosorbent assays (ELISA). Calculated IC50 ranking analysis allowed the selection of the candidate octapeptide containing two (S)-2-amino-4-pentynoic acid (L-Pra) residues Ac-Pra-RRN(Glc)GHT-Pra-NH2 , with an IC50 in the nanomolar range. This peptide was adequately modified for solid-phase ELISA (SP-ELISA) and surface plasmon resonance (SPR) experiments. Pra-RRN(Glc)GHT-Pra-NH2 peptide was modified with an alkyl chain linked to the N-terminus, favoring immobilization on solid phase in SP-ELISA and differentiating IgG antibody recognition between patients and healthy blood donors with a high specificity. However, this peptide displayed a loss in IgM specificity and sensitivity. Moreover, an analog was obtained after modification of the octapeptide candidate Ac-Pra-RRN(Glc)GHT-Pra-NH2 to favor immobilization on SPR sensor chips. SPR technology allowed us to determine its affinity (KD  = 16.4 nM), 2.3 times lower than the affinity of the original glucopeptide CSF114(Glc) (KD  = 7.1 nM).

  1. Activation of Type II Cells into Regenerative Stem Cell Antigen-1+ Cells during Alveolar Repair

    PubMed Central

    Kumar, Varsha Suresh; Zhang, Wei; Rehman, Jalees; Malik, Asrar B.

    2015-01-01

    The alveolar epithelium is composed of two cell types: type I cells comprise 95% of the gas exchange surface area, whereas type II cells secrete surfactant, while retaining the ability to convert into type I cells to induce alveolar repair. Using lineage-tracing analyses in the mouse model of Pseudomonas aeruginosa–induced lung injury, we identified a population of stem cell antigen (Sca)-1–expressing type II cells with progenitor cell properties that mediate alveolar repair. These cells were shown to be distinct from previously reported Sca-1–expressing bronchioalveolar stem cells. Microarray and Wnt reporter studies showed that surfactant protein (Sp)-C+Sca-1+ cells expressed Wnt signaling pathway genes, and inhibiting Wnt/β-catenin signaling prevented the regenerative function of Sp-C+Sca-1+ cells in vitro. Thus, P. aeruginosa–mediated lung injury induces the generation of a Sca-1+ subset of type II cells. The progenitor phenotype of the Sp-C+Sca-1+ cells that mediates alveolar epithelial repair might involve Wnt signaling. PMID:25474582

  2. Augmenting antitumor T-cell responses to mimotope vaccination by boosting with native tumor antigens.

    PubMed

    Buhrman, Jonathan D; Jordan, Kimberly R; U'ren, Lance; Sprague, Jonathan; Kemmler, Charles B; Slansky, Jill E

    2013-01-01

    Vaccination with antigens expressed by tumors is one strategy for stimulating enhanced T-cell responses against tumors. However, these peptide vaccines rarely result in efficient expansion of tumor-specific T cells or responses that protect against tumor growth. Mimotopes, or peptide mimics of tumor antigens, elicit increased numbers of T cells that crossreact with the native tumor antigen, resulting in potent antitumor responses. Unfortunately, mimotopes may also elicit cells that do not crossreact or have low affinity for tumor antigen. We previously showed that one such mimotope of the dominant MHC class I tumor antigen of a mouse colon carcinoma cell line stimulates a tumor-specific T-cell clone and elicits antigen-specific cells in vivo, yet protects poorly against tumor growth. We hypothesized that boosting the mimotope vaccine with the native tumor antigen would focus the T-cell response elicited by the mimotope toward high affinity, tumor-specific T cells. We show that priming T cells with the mimotope, followed by a native tumor-antigen boost, improves tumor immunity compared with T cells elicited by the same prime with a mimotope boost. Our data suggest that the improved tumor immunity results from the expansion of mimotope-elicited tumor-specific T cells that have increased avidity for the tumor antigen. The enhanced T cells are phenotypically distinct and enriched for T-cell receptors previously correlated with improved antitumor immunity. These results suggest that incorporation of native antigen into clinical mimotope vaccine regimens may improve the efficacy of antitumor T-cell responses.

  3. Induction of Neonatal Tolerance to Mls^a Antigens by CD8^+ T Cells

    NASA Astrophysics Data System (ADS)

    Webb, Susan R.; Sprent, Jonathan

    1990-06-01

    Antigen-specific tolerance of T cells to minor lymphocyte stimulatory (Mis) antigens can be induced in mice by neonatal injection of foreign lymphohematopoietic cells. Although immune responses to Mls^a antigens are controlled by B cells, CD8^+ T cells were the most effective cell type for induction of Mls^a tolerance. Tolerance was evident in both thymus and lymph nodes and could be induced by as few as 2 x 10^4 CD8^+ T cells; these cells were 50 to 100 times as potent as CD4^+ cells or B cells in causing functional tolerance and deletion of Vβ6^+ T cells. Thus, intrathymic contact with antigens expressed on CD8^+ T cells may play an important role in controlling the normal development of tolerance.

  4. Expression of basement membrane antigens in spindle cell melanoma.

    PubMed

    Prieto, V G; Woodruff, J M

    1998-07-01

    Spindle cell melanoma (SCM) is an uncommon form of melanoma that may be confused histologically with other tumors, including malignant peripheral nerve sheath tumors (MPNST). Tumors with neural differentiation and melanocytic nevi may both show basement membrane immunohistochemically and at the ultrastructural level. However, most ultrastructural studies of melanoma have failed to demonstrate well formed basement membrane around tumor cells. The presence of basement membrane has been used by some authors as evidence favoring MPNST, as opposed to SCM. To evaluate this distinction immunohistochemically, 22 primary and metastatic cutaneous melanomas having a spindle cell component (SCM) were studied using monoclonal antibodies against laminin and Type IV collagen. S100 protein and HMB45 antigen expression were also studied. All but one of the SCM were reactive for S100 protein in at least 25% of the cells. Thirteen of 20 tumors (65%) were focally reactive with HMB45. Laminin was expressed in 42% of the tumors (only membranous pattern in 3; cytoplasmic and membranous in 5). Seventeen tumors (77%) expressed type IV collagen (only membranous pattern in 7; cytoplasmic and membranous pattern in 10). Laminin and type IV collagen, known components of basement membrane, are often found in SCM. Therefore, their detection cannot be used to distinguish SCM from MPNST.

  5. Combining computer algorithms with experimental approaches permits the rapid and accurate identification of T cell epitopes from defined antigens.

    PubMed

    Schirle, M; Weinschenk, T; Stevanović, S

    2001-11-01

    The identification of T cell epitopes from immunologically relevant antigens remains a critical step in the development of vaccines and methods for monitoring of T cell responses. This review presents an overview of strategies that employ computer algorithms for the selection of candidate peptides from defined proteins and subsequent verification of their in vivo relevance by experimental approaches. Several computer algorithms are currently being used for epitope prediction of various major histocompatibility complex (MHC) class I and II molecules, based either on the analysis of natural MHC ligands or on the binding properties of synthetic peptides. Moreover, the analysis of proteasomal digests of peptides and whole proteins has led to the development of algorithms for the prediction of proteasomal cleavages. In order to verify the generation of the predicted peptides during antigen processing in vivo as well as their immunogenic potential, several experimental approaches have been pursued in the recent past. Mass spectrometry-based bioanalytical approaches have been used specifically to detect predicted peptides among isolated natural ligands. Other strategies employ various methods for the stimulation of primary T cell responses against the predicted peptides and subsequent testing of the recognition pattern towards target cells that express the antigen.

  6. Beta cell antigens in type 1 diabetes: triggers in pathogenesis and therapeutic targets

    PubMed Central

    Mauvais, François-Xavier; Diana, Julien; van Endert, Peter

    2016-01-01

    Research focusing on type 1 diabetes (T1D) autoantigens aims to explore our understanding of these beta cell proteins in order to design assays for monitoring the pathogenic autoimmune response, as well as safe and efficient therapies preventing or stopping it. In this review, we will discuss progress made in the last 5 years with respect to mechanistic understanding, diagnostic monitoring, and therapeutic modulation of the autoantigen-specific cellular immune response in T1D. Some technical progress in monitoring tools has been made; however, the potential of recent technologies for highly multiplexed exploration of human cellular immune responses remains to be exploited in T1D research, as it may be the key to the identification of surrogate markers of disease progression that are still wanting. Detailed analysis of autoantigen recognition by T cells suggests an important role of non-conventional antigen presentation and processing in beta cell-directed autoimmunity, but the impact of this in human T1D has been little explored. Finally, therapeutic administration of autoantigens to T1D patients has produced disappointing results. The application of novel modes of autoantigen administration, careful translation of mechanistic understanding obtained in preclinical studies and in vitro with human cells, and combination therapies including CD3 antibodies may help to make autoantigen-based immunotherapy for T1D a success story in the future. PMID:27158463

  7. Antigenic modulation of metastatic breast and ovary carcinoma cells by intracavitary injection of IFN-alpha.

    PubMed Central

    Giacomini, P.; Mottolese, M.; Fraioli, R.; Benevolo, M.; Venturo, I.; Natali, P. G.

    1992-01-01

    Antigenic modulation of major histocompatibility and tumour associated antigens was observed in neoplastic cells obtained from patients with pleural and abdominal effusions of breast and ovary carcinomas following a single intracavitary dose of 18 x 10(6) U recombinant IFN-alpha. This regimen resulted in antigenic modulation in seven out of 11 tested cases, suggesting a potential, although limited, responsiveness of at least a fraction of breast and ovary carcinoma cells to in situ biomodification with IFN-alpha. PMID:1503908

  8. The effects of Fasciola hepatica tegumental antigens on mast cell function.

    PubMed

    Vukman, Krisztina V; Adams, Paul N; Dowling, David; Metz, Martin; Maurer, Marcus; O'Neill, Sandra M

    2013-06-01

    Fasciola hepatica infection is associated with T helper 2/T regulatory immune responses and increased mast cell numbers. The aim of this study was to examine the interaction between F. hepatica tegumental coat antigen and mast cells in vivo and in vitro. Firstly, BALB/C, C57BL/6 or STAT6(-/-) mice were infected with F. hepatica metacercarie or mice were treated with F. hepatica tegumental coat antigen and then mast cells numbers in the peritoneal cavity and/or the liver were quantified. Also, the proliferation, chemotaxis, degranulation and cytokine secretion of mast cells from bone marrow or from peritoneal exudate cells stimulated with F. hepatica tegumental coat antigen were measured. Finally, we tested whether F. hepatica tegumental coat antigen inhibits degranulation of mast cells in vivo in a passive cutaneous and systemic anaphylaxis mouse model. Mast cell numbers increased in the peritoneal cavity and liver of F. hepatica infected mice, and this was mimicked by injection of F. hepatica tegumental coat antigen in a STAT6(-/-) independent manner. The increase in mast cell number was not the result of F. hepatica tegumental coat antigen-induced proliferation; rather F. hepatica tegumental coat antigen indirectly induces mast cell migration by dendritic cell-derived chemokines. Fasciola hepatica tegumental coat antigen interactions with mast cells do not drive T helper 2 or T regulatory immune responses. These studies on mast cell and F. hepatica tegumental coat antigen interaction may help us to understand the function of mast cells in immunity against F. hepatica and the immunomodulatory effect of F. hepatica tegumental coat antigen on these cells.

  9. Isolation and characterization of NIH 3T3 cells expressing polyomavirus small T antigen

    SciTech Connect

    Noda, T.; Satake, M.; Robins, T.; Ito, Y.

    1986-10-01

    The polyomavirus small T-antigen gene, together with the polyomavirus promoter, was inserted into retrovirus vector pGV16 which contains the Moloney sarcoma virus long terminal repeat and neomycin resistance gene driven by the simian virus 40 promoter. This expression vector, pGVST, was packaged into retrovirus particles by transfection of PSI2 cells which harbor packaging-defective murine retrovirus genome. NIH 3T3 cells were infected by this replication-defective retrovirus containing pGVST. Of the 15 G418-resistant cell clones, 8 express small T antigen at various levels as revealed by immunoprecipitation. A cellular protein with an apparent molecular weight of about 32,000 coprecipitates with small T antigen. Immunofluorescent staining shows that small T antigen is mainly present in the nuclei. Morphologically, cells expressing small T antigen are indistinguishable from parental NIH 3T3 cells and have a microfilament pattern similar to that in parental NIH 3T3 cells. Cells expressing small T antigen form a flat monolayer but continue to grow beyond the saturation density observed for parental NIH 3T3 cells and eventually come off the culture plate as a result of overconfluency. There is some correlation between the level of expression of small T antigen and the growth rate of the cells. Small T-antigen-expressing cells form small colonies in soft agar. However, the proportion of cells which form these small colonies is rather small. A clone of these cells tested did not form tumors in nude mice within 3 months after inoculation of 10/sup 6/ cells per animal. Thus, present studies establish that the small T antigen of polyomavirus is a second nucleus-localized transforming gene product of the virus (the first one being large T antigen) and by itself has a function which is to stimulate the growth of NIH 3T3 cells beyond their saturation density in monolayer culture.

  10. Lenalidomide enhances antitumor functions of chimeric antigen receptor modified T cells.

    PubMed

    Otáhal, Pavel; Průková, Dana; Král, Vlastimil; Fabry, Milan; Vočková, Petra; Latečková, Lucie; Trněný, Marek; Klener, Pavel

    2016-04-01

    Tumor immunotherapy based on the use of chimeric antigen receptor modified T cells (CAR T cells) is a promising approach for the treatment of refractory hematological malignancies. However, a robust response mediated by CAR T cells is observed only in a minority of patients and the expansion and persistence of CAR T cells in vivo is mostly unpredictable.Lenalidomide (LEN) is an immunomodulatory drug currently approved for the treatment of multiple myeloma (MM) and mantle cell lymphoma, while it is clinically tested in the therapy of diffuse large B-cell lymphoma of activated B cell immunophenotype. LEN was shown to increase antitumor immune responses at least partially by modulating the activity of E3 ubiquitin ligase Cereblon, which leads to increased ubiquitinylation of Ikaros and Aiolos transcription factors, which in turn results in changed expression of various receptors on the surface of tumor cells. In order to enhance the effectiveness of CAR-based immunotherapy, we assessed the anti-lymphoma efficacy of LEN in combination with CAR19 T cells or CAR20 T cells in vitro and in vivo using various murine models of aggressive B-cell non-Hodgkin lymphomas (B-NHL).Immunodeficient NSG mice were transplanted with various human B-NHL cells followed by treatment with CAR19 or CAR20 T cells with or without LEN. Next, CAR19 T cells were subjected to series of tests in vitro to evaluate their response and signaling capacity following recognition of B cell in the presence or absence of LEN.Our data shows that LEN significantly enhances antitumor functions of CAR19 and CAR20 T cells in vivo. Additionally, it enhances production of interferon gamma by CAR19 T cells and augments cell signaling via CAR19 protein in T cells in vitro. Our data further suggests that LEN works through direct effects on T cells but not on B-NHL cells. The biochemical events underlying this costimulatory effect of LEN are currently being investigated. In summary, our data supports the use of LEN for

  11. Lenalidomide enhances antitumor functions of chimeric antigen receptor modified T cells

    PubMed Central

    Otáhal, Pavel; Průková, Dana; Král, Vlastimil; Fabry, Milan; Vočková, Petra; Latečková, Lucie; Trněný, Marek; Klener, Pavel

    2016-01-01

    ABSTRACT Tumor immunotherapy based on the use of chimeric antigen receptor modified T cells (CAR T cells) is a promising approach for the treatment of refractory hematological malignancies. However, a robust response mediated by CAR T cells is observed only in a minority of patients and the expansion and persistence of CAR T cells in vivo is mostly unpredictable.Lenalidomide (LEN) is an immunomodulatory drug currently approved for the treatment of multiple myeloma (MM) and mantle cell lymphoma, while it is clinically tested in the therapy of diffuse large B-cell lymphoma of activated B cell immunophenotype. LEN was shown to increase antitumor immune responses at least partially by modulating the activity of E3 ubiquitin ligase Cereblon, which leads to increased ubiquitinylation of Ikaros and Aiolos transcription factors, which in turn results in changed expression of various receptors on the surface of tumor cells. In order to enhance the effectiveness of CAR-based immunotherapy, we assessed the anti-lymphoma efficacy of LEN in combination with CAR19 T cells or CAR20 T cells in vitro and in vivo using various murine models of aggressive B-cell non-Hodgkin lymphomas (B-NHL).Immunodeficient NSG mice were transplanted with various human B-NHL cells followed by treatment with CAR19 or CAR20 T cells with or without LEN. Next, CAR19 T cells were subjected to series of tests in vitro to evaluate their response and signaling capacity following recognition of B cell in the presence or absence of LEN.Our data shows that LEN significantly enhances antitumor functions of CAR19 and CAR20 T cells in vivo. Additionally, it enhances production of interferon gamma by CAR19 T cells and augments cell signaling via CAR19 protein in T cells in vitro. Our data further suggests that LEN works through direct effects on T cells but not on B-NHL cells. The biochemical events underlying this costimulatory effect of LEN are currently being investigated. In summary, our data supports the use

  12. Phospholipase treatment of accessory cells that have been exposed to antigen selectively inhibits antigen-specific Ia-restricted, but not allospecific, stimulation of T lymphocytes.

    PubMed Central

    Falo, L D; Benacerraf, B; Rock, K L

    1986-01-01

    The corecognition of antigen and class II major histocompatibility complex (MHC) molecules (Ia molecules) by the T-cell receptor is a cell surface event. Before antigen is recognized, it must be taken up, processed, and displayed on the surface of an Ia-bearing accessory cell (antigen-presenting cell, APC). The exact nature of antigen processing and the subsequent associations of antigen with the APC plasma membrane, Ia molecules, and/or the T-cell receptor are not well defined. To further analyze these events, we have characterized the processing and presentation of the soluble polypeptide antigen bovine insulin. We found that this antigen requires APC-dependent processing, as evidenced by the inability of metabolically inactivated APCs to present native antigen to antigen plus Ia-specific T-T hybridomas. The ability of the same APCs to present antigen after uptake and processing showed that this antigen subsequently becomes stably associated with the APC plasma membrane. To characterize the basis for this association, we analyzed its sensitivity to enzymatic digestion. APCs exposed to antigen, treated with phospholipase A2, and then immediately fixed lost the ability to stimulate bovine insulin plus I-Ad-specific hybridomas. In contrast, the ability of these same APCs to stimulate I-Ad allospecific hybridomas was unaffected. This effect of phospholipase is not mimicked by the broadly active protease Pronase, nor is there evidence for contaminating proteases in the phospholipase preparation. These results suggest that one consequence of antigen processing may be an antigen-lipid association that contributes to the anchoring of antigen to the APC membrane. The implications of this model are discussed. PMID:3529095

  13. Natural and adaptive IgM antibodies in the recognition of tumor-associated antigens of breast cancer (Review)

    PubMed Central

    DÍAZ-ZARAGOZA, MARIANA; HERNÁNDEZ-ÁVILA, RICARDO; VIEDMA-RODRÍGUEZ, RUBÍ; ARENAS-ARANDA, DIEGO; OSTOA-SALOMA, PEDRO

    2015-01-01

    For early detection of cancer, education and screening are important, but the most critical factor is the development of early diagnostic tools. Methods that recognize the warning signs of cancer and take prompt action lead to an early diagnosis; simple tests can identify individuals in a healthy population who have the disease but have not developed symptoms. Early detection of cancer is significant and is one of the most promising approaches by which to reduce the growing cancer burden and guide curative treatment. The early diagnosis of patients with breast cancer is challenging, since it is the most common cancer in women worldwide. Despite the advent of mammography in screening for breast cancer, low-resource, low-cost alternative tools must be implemented to complement mammography findings. IgM is part of the first line of defense of an organism and is responsible for recognizing and eliminating infectious particles and removing transformed cells. Most studies on breast cancer have focused on the development of IgG-like molecules as biomarkers or as a treatment for the advanced stages of cancer, but autoantibodies (IgM) and tumor-associated antigens (proteins or carbohydrates with aberrant structures) have not been examined as early diagnostic tools for breast cancer. The present review summarizes the function of natural and adaptive IgM in eliminating cancer cells in the early stages of pathology and their value as early diagnostic tools. IgM, as a component of the immune system, is being used to identify tumor-associated antigens and tumor-associated carbohydrate antigens. PMID:26133558

  14. Red blood cells as innovative antigen carrier to induce specific immune tolerance.

    PubMed

    Cremel, Magali; Guérin, Nathalie; Horand, Françoise; Banz, Alice; Godfrin, Yann

    2013-02-25

    The route of administration, the dose of antigen as well as the type of antigen-presenting cells (APCs) targeted are important factors to induce immune tolerance. Despite encouraging results obtained in animal models, intravenous injection of soluble antigen is unsuccessful in human clinical trials on autoimmune disease due to inefficient antigen delivery. To improve antigen delivery, we used mouse red blood cells (RBCs) as antigen vehicles to specifically target APCs which are responsible for removal of senescent RBCs after phagocytosis. In this study, we demonstrated that antigen-delivery by RBCs induced a strong decrease in the humoral response compared with the ovalbumin (OVA) free form in mice. In addition, OVA-loaded RBC treated with [bis(sulphosuccinimidyl)] suberate (BS3), a chemical compound known to enhance RBC phagocytosis, induced an inhibition of antigen-specific T cell responses and an increase in the percentage of regulatory T cells. The state of tolerance induced is long lasting, antigen-specific and sufficiently robust to withstand immunization with antigen mixed with cholera toxin adjuvant. This RBC strategy, which does not abolish the immune system, constitutes an attractive approach for induction of tolerance compared to systemic immunosuppressant therapies already in use.

  15. Inherent ER stress in pancreatic islet β cells causes self-recognition by autoreactive T cells in type 1 diabetes.

    PubMed

    Marré, Meghan L; Profozich, Jennifer L; Coneybeer, Jorge T; Geng, Xuehui; Bertera, Suzanne; Ford, Michael J; Trucco, Massimo; Piganelli, Jon D

    2016-08-01

    Type 1 diabetes (T1D) is an autoimmune disease characterized by pancreatic β cell destruction induced by islet reactive T cells that have escaped central tolerance. Many physiological and environmental triggers associated with T1D result in β cell endoplasmic reticulum (ER) stress and dysfunction, increasing the potential for abnormal post-translational modification (PTM) of proteins. We hypothesized that β cell ER stress induced by environmental and physiological conditions generates abnormally-modified proteins for the T1D autoimmune response. To test this hypothesis we exposed the murine CD4(+) diabetogenic BDC2.5 T cell clone to murine islets in which ER stress had been induced chemically (Thapsigargin). The BDC2.5 T cell IFNγ response to these cells was significantly increased compared to non-treated islets. This β cell ER stress increased activity of the calcium (Ca(2+))-dependent PTM enzyme tissue transglutaminase 2 (Tgase2), which was necessary for full stress-dependent immunogenicity. Indeed, BDC2.5 T cells responded more strongly to their antigen after its modification by Tgase2. Finally, exposure of non-antigenic murine insulinomas to chemical ER stress in vitro or physiological ER stress in vivo caused increased ER stress and Tgase2 activity, culminating in higher BDC2.5 responses. Thus, β cell ER stress induced by chemical and physiological triggers leads to β cell immunogenicity through Ca(2+)-dependent PTM. These findings elucidate a mechanism of how β cell proteins are modified and become immunogenic, and reveal a novel opportunity for preventing β cell recognition by autoreactive T cells.

  16. Cell Type-Specific Regulation of Immunological Synapse Dynamics by B7 Ligand Recognition

    PubMed Central

    Brzostek, Joanna; Gascoigne, Nicholas R. J.; Rybakin, Vasily

    2016-01-01

    B7 proteins CD80 (B7-1) and CD86 (B7-2) are expressed on most antigen-presenting cells and provide critical co-stimulatory or inhibitory input to T cells via their T-cell-expressed receptors: CD28 and CTLA-4. CD28 is expressed on effector T cells and regulatory T cells (Tregs), and CD28-dependent signals are required for optimum activation of effector T cell functions. CD28 ligation on effector T cells leads to formation of distinct molecular patterns and induction of cytoskeletal rearrangements at the immunological synapse (IS). CD28 plays a critical role in recruitment of protein kinase C (PKC)-θ to the effector T cell IS. CTLA-4 is constitutively expressed on the surface of Tregs, but it is expressed on effector T cells only after activation. As CTLA-4 binds to B7 proteins with significantly higher affinity than CD28, B7 ligand recognition by cells expressing both receptors leads to displacement of CD28 and PKC-θ from the IS. In Tregs, B7 ligand recognition leads to recruitment of CTLA-4 and PKC-η to the IS. CTLA-4 plays a role in regulation of T effector and Treg IS stability and cell motility. Due to their important roles in regulating T-cell-mediated responses, B7 receptors are emerging as important drug targets in oncology. In this review, we present an integrated summary of current knowledge about the role of B7 family receptor–ligand interactions in the regulation of spatial and temporal IS dynamics in effector and Tregs. PMID:26870040

  17. Sensing of cell stress by human γδ TCR-dependent recognition of annexin A2

    PubMed Central

    Pappalardo, Angela; Kaminski, Hannah; Willcox, Carrie R.; Pitard, Vincent; Netzer, Sonia; Khairallah, Camille; Lomenech, Anne-Marie; Harly, Christelle; Bonneville, Marc; Moreau, Jean-François; Scotet, Emmanuel; Willcox, Benjamin E.; Faustin, Benjamin; Déchanet-Merville, Julie

    2017-01-01

    Human γδ T cells comprise a first line of defense through T-cell receptor (TCR) recognition of stressed cells. However, the molecular determinants and stress pathways involved in this recognition are largely unknown. Here we show that exposure of tumor cells to various stress situations led to tumor cell recognition by a Vγ8Vδ3 TCR. Using a strategy that we previously developed to identify antigenic ligands of γδ TCRs, annexin A2 was identified as the direct ligand of Vγ8Vδ3 TCR, and was found to be expressed on tumor cells upon the stress situations tested in a reactive oxygen species-dependent manner. Moreover, purified annexin A2 was able to stimulate the proliferation of a Vδ2neg γδ T-cell subset within peripheral blood mononuclear cells and other annexin A2-specific Vδ2neg γδ T-cell clones could be derived from peripheral blood mononuclear cells. We thus propose membrane exposure of annexin A2 as an oxidative stress signal for some Vδ2neg γδ T cells that could be involved in an adaptive stress surveillance. PMID:28270598

  18. Identification of a Highly Antigenic Linear B Cell Epitope within Plasmodium vivax Apical Membrane Antigen 1 (AMA-1)

    PubMed Central

    Bueno, Lilian Lacerda; Lobo, Francisco Pereira; Morais, Cristiane Guimarães; Mourão, Luíza Carvalho; de Ávila, Ricardo Andrez Machado; Soares, Irene Silva; Fontes, Cor Jesus; Lacerda, Marcus Vinícius; Olórtegui, Carlos Chavez; Bartholomeu, Daniella Castanheira; Fujiwara, Ricardo Toshio; Braga, Érika Martins

    2011-01-01

    Apical membrane antigen 1 (AMA-1) is considered to be a major candidate antigen for a malaria vaccine. Previous immunoepidemiological studies of naturally acquired immunity to Plasmodium vivax AMA-1 (PvAMA-1) have shown a higher prevalence of specific antibodies to domain II (DII) of AMA-1. In the present study, we confirmed that specific antibody responses from naturally infected individuals were highly reactive to both full-length AMA-1 and DII. Also, we demonstrated a strong association between AMA-1 and DII IgG and IgG subclass responses. We analyzed the primary sequence of PvAMA-1 for B cell linear epitopes co-occurring with intrinsically unstructured/disordered regions (IURs). The B cell epitope comprising the amino acid sequence 290–307 of PvAMA-1 (SASDQPTQYEEEMTDYQK), with the highest prediction scores, was identified in domain II and further selected for chemical synthesis and immunological testing. The antigenicity of the synthetic peptide was identified by serological analysis using sera from P. vivax-infected individuals who were knowingly reactive to the PvAMA-1 ectodomain only, domain II only, or reactive to both antigens. Although the synthetic peptide was recognized by all serum samples specific to domain II, serum with reactivity only to the full-length protein presented 58.3% positivity. Moreover, IgG reactivity against PvAMA-1 and domain II after depletion of specific synthetic peptide antibodies was reduced by 18% and 33% (P = 0.0001 for both), respectively. These results suggest that the linear epitope SASDQPTQYEEEMTDYQK is highly antigenic during natural human infections and is an important antigenic region of the domain II of PvAMA-1, suggesting its possible future use in pre-clinical studies. PMID:21713006

  19. Neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues

    SciTech Connect

    Terasawa, Masao; Nagata, Kisaburo; Kobayashi, Yoshiro

    2008-12-12

    Antigen-transporting cells take up pathogens, and then migrate from sites of inflammation to secondary lymphoid tissues to induce an immune response. Among antigen-transporting cells, dendritic cells (DCs) are believed to be the most potent and professional antigen-presenting cells that can stimulate naive T cells. However, the cells that transport antigens, tumor cell antigens in particular, have not been clearly identified. In this study we have analyzed what types of cells transport tumor cell antigens to secondary lymphoid tissues. We show that neutrophils, monocytes and macrophages but not DCs engulf X-irradiated P388 leukemic cells after their injection into the peritoneal cavity, and that neutrophils and monocytes but not macrophages migrate to the parathymic lymph nodes (pLN), the blood, and then the spleen. The monocytes in the pLN comprise Gr-1{sup -} and Gr-1{sup +} ones, and some of these cells express CD11c. Overall, this study demonstrates that neutrophils and monocytes transport tumor cell antigens from the peritoneal cavity to secondary lymphoid tissues.

  20. Usage of Murine T-cell Hybridoma Cells as Responder Cells Reveals Interference of Helicobacter Pylori with Human Dendritic Cell-mediated Antigen Presentation

    PubMed Central

    Fehlings, Michael; Drobbe, Lea; Beigier-Bompadre, Macarena; Viveros, Pablo Renner; Moos, Verena; Schneider, Thomas; Meyer, Thomas F.; Aebischer, Toni; Ignatius, Ralf

    2016-01-01

    Direct effects of Helicobacter pylori (H. pylori) on human CD4+ T-cells hamper disentangling a possible bacterial-mediated interference with major histocompatibility complex class II (MHC-II)-dependent antigen presentation to these cells. To overcome this limitation, we employed a previously described assay, which enables assessing human antigen-processing cell function by using murine T-cell hybridoma cells restricted by human leukocyte antigen (HLA) alleles. HLA-DR1+ monocyte-derived dendritic cells were exposed to H. pylori and pulsed with the antigen 85B from Mycobacterium tuberculosis (M. tuberculosis). Interleukin-2 (IL-2) secretion by AG85Baa97-112-specific hybridoma cells was then evaluated as an integral reporter of cognate antigen presentation. This methodology enabled revealing of interference of H. pylori with the antigen-presenting capacity of human dendritic cells. PMID:27980859

  1. Extra- and intracellular innate immune recognition in endothelial cells.

    PubMed

    Opitz, Bastian; Hippenstiel, Stefan; Eitel, Julia; Suttorp, Norbert

    2007-08-01

    The innate immune system represents the principal sensor of infections in multicellular organisms and might also mediate responses to some endogenous molecules. In this context, endothelial cells are among the first cells coming into contact with microbial or endogenous (danger-associated) molecules or whole pathogens entering the bloodstream. Since many bacteria and viruses invade the endothelium, endothelial cells are equipped with both extracellular and cytosolic surveillance systems capable of sensing microbial components, and endogenous danger-associated molecules. The receptor molecules, called pattern recognition receptors (PRRs), are classified as transmembrane or cytosolic molecules. While the transmembrane PRRs recognize extracellular and membrane-enclosed foreign organisms, the cytosolic PRRs appear to sense intracellular infections. Here we focus on both PRR classes in general, and outline the current knowledge of extra- and intracellular pattern recognition in endothelial cells and its potential role in vascular diseases and sepsis.

  2. Nonhuman TRIM5 Variants Enhance Recognition of HIV-1-Infected Cells by CD8+ T Cells

    PubMed Central

    Jimenez-Moyano, Esther; Ruiz, Alba; Kløverpris, Henrik N.; Rodriguez-Plata, Maria T.; Peña, Ruth; Blondeau, Caroline; Selwood, David L.; Izquierdo-Useros, Nuria; Moris, Arnaud; Clotet, Bonaventura; Goulder, Philip; Towers, Greg J.

    2016-01-01

    ABSTRACT Tripartite motif-containing protein 5 (TRIM5) restricts human immunodeficiency virus type 1 (HIV-1) in a species-specific manner by uncoating viral particles while activating early innate responses. Although the contribution of TRIM5 proteins to cellular immunity has not yet been studied, their interactions with the incoming viral capsid and the cellular proteasome led us to hypothesize a role for them. Here, we investigate whether the expression of two nonhuman TRIM5 orthologs, rhesus TRIM5α (RhT5) and TRIM-cyclophilin A (TCyp), both of which are potent restrictors of HIV-1, could enhance immune recognition of infected cells by CD8+ T cells. We illustrate how TRIM5 restriction improves CD8+ T-cell-mediated HIV-1 inhibition. Moreover, when TRIM5 activity was blocked by the nonimmunosuppressive analog of cyclosporine (CsA), sarcosine-3(4-methylbenzoate)–CsA (SmBz-CsA), we found a significant reduction in CD107a/MIP-1β expression in HIV-1-specific CD8+ T cells. This finding underscores the direct link between TRIM5 restriction and activation of CD8+ T-cell responses. Interestingly, cells expressing RhT5 induced stronger CD8+ T-cell responses through the specific recognition of the HIV-1 capsid by the immune system. The underlying mechanism of this process may involve TRIM5-specific capsid recruitment to cellular proteasomes and increase peptide availability for loading and presentation of HLA class I antigens. In summary, we identified a novel function for nonhuman TRIM5 variants in cellular immunity. We hypothesize that TRIM5 can couple innate viral sensing and CD8+ T-cell activation to increase species barriers against retrovirus infection. IMPORTANCE New therapeutics to tackle HIV-1 infection should aim to combine rapid innate viral sensing and cellular immune recognition. Such strategies could prevent seeding of the viral reservoir and the immune damage that occurs during acute infection. The nonhuman TRIM5 variants, rhesus TRIM5α (RhT5) and TRIM

  3. A Molecular Switch Abrogates Glycoprotein 100 (gp100) T-cell Receptor (TCR) Targeting of a Human Melanoma Antigen*

    PubMed Central

    Bianchi, Valentina; Bulek, Anna; Fuller, Anna; Lloyd, Angharad; Attaf, Meriem; Rizkallah, Pierre J.; Dolton, Garry; Sewell, Andrew K.; Cole, David K.

    2016-01-01

    Human CD8+ cytotoxic T lymphocytes can mediate tumor regression in melanoma through the specific recognition of HLA-restricted peptides. Because of the relatively weak affinity of most anti-cancer T-cell receptors (TCRs), there is growing emphasis on immunizing melanoma patients with altered peptide ligands in order to induce strong anti-tumor immunity capable of breaking tolerance toward these self-antigens. However, previous studies have shown that these immunogenic designer peptides are not always effective. The melanocyte differentiation protein, glycoprotein 100 (gp100), encodes a naturally processed epitope that is an attractive target for melanoma immunotherapies, in particular peptide-based vaccines. Previous studies have shown that substitutions at peptide residue Glu3 have a broad negative impact on polyclonal T-cell responses. Here, we describe the first atomic structure of a natural cognate TCR in complex with this gp100 epitope and highlight the relatively high affinity of the interaction. Alanine scan mutagenesis performed across the gp100280–288 peptide showed that Glu3 was critically important for TCR binding. Unexpectedly, structural analysis demonstrated that the Glu3 → Ala substitution resulted in a molecular switch that was transmitted to adjacent residues, abrogating TCR binding and T-cell recognition. These findings help to clarify the mechanism of T-cell recognition of gp100 during melanoma responses and could direct the development of altered peptides for vaccination. PMID:26917722

  4. Killer artificial antigen-presenting cells: a novel strategy to delete specific T cells.

    PubMed

    Schütz, Christian; Fleck, Martin; Mackensen, Andreas; Zoso, Alessia; Halbritter, Dagmar; Schneck, Jonathan P; Oelke, Mathias

    2008-04-01

    Several cell-based immunotherapy strategies have been developed to specifically modulate T cell-mediated immune responses. These methods frequently rely on the utilization of tolerogenic cell-based antigen-presenting cells (APCs). However, APCs are highly sensitive to cytotoxic T-cell responses, thus limiting their therapeutic capacity. Here, we describe a novel bead-based approach to modulate T-cell responses in an antigen-specific fashion. We have generated killer artificial APCs (kappaaAPCs) by coupling an apoptosis-inducing alpha-Fas (CD95) IgM mAb together with HLA-A2 Ig molecules onto beads. These kappaaAPCs deplete targeted antigen-specific T cells in a Fas/Fas ligand (FasL)-dependent fashion. T-cell depletion in cocultures is rapidly initiated (30 minutes), dependent on the amount of kappaaAPCs and independent of activation-induced cell death (AICD). kappaaAPCs represent a novel technology that can control T cell-mediated immune responses, and therefore has potential for use in treatment of autoimmune diseases and allograft rejection.

  5. CD1 antigen presentation: how it works.

    PubMed

    Barral, Duarte C; Brenner, Michael B

    2007-12-01

    The classic concept of self-non-self discrimination by the immune system focused on the recognition of fragments from proteins presented by classical MHC molecules. However, the discovery of MHC-class-I-like CD1 antigen-presentation molecules now explains how the immune system also recognizes the abundant and diverse universe of lipid-containing antigens. The CD1 molecules bind and present amphipathic lipid antigens for recognition by T-cell receptors. Here, we outline the recent advances in our understanding of how the processes of CD1 assembly, trafficking, lipid-antigen binding and T-cell activation are achieved and the new insights into how lipid antigens differentially elicit CD1-restricted innate and adaptive T-cell responses.

  6. Leishmania infantum antigens modulate memory cell subsets of liver resident T lymphocyte.

    PubMed

    Rodrigues, A; Claro, M; Alexandre-Pires, G; Santos-Mateus, D; Martins, C; Valério-Bolas, A; Rafael-Fernandes, M; Pereira, M A; Pereira da Fonseca, I; Tomás, A M; Santos-Gomes, G

    2017-02-01

    In the recent years, the liver has been recognized as an important immune organ with major regulatory functions and immune memory, adding to the well-described vital metabolic functions. There are evidences from experimental infections performed with visceral Leishmania species that immune responses to parasite infection can be organ-specific. The liver is the compartment of acute resolving infection, with minimal tissue damage and resistance to reinfection, whereas the spleen is the compartment of parasite persistence. Control of hepatic infection in mice requires a coordinated immune response that involves the development of inflammatory granulomas. It is also described that the liver harbors populations of resident lymphocytes, which may exhibit memory characteristics. Therefore, the present study aims to address the role of the liver as an immune memory organ in the context of Leishmania infantum infection, by characterizing phenotypically resident liver T lymphocytes. The dynamics of memory T cells in L. infantum infected BALB/c mice and the effect of anti-leishmanial treatment in the differentiation of memory cell subsets were analyzed. The potential of recognition, differentiation and selection of memory lymphocytes by three L. infantum recombinant proteins were also explored. L. infantum infection generates effector and central memory T cells, but the cells did not expand when recalled, demonstrating a possible parasite silencing effect. The treatment with a leishmanicidal drug (antimoniate meglumine) increases the levels of memory and effector T cells, eliciting a more robust hepatic immune response. L. infantum parasites with a decreased sensitivity to the leishmanicidal drug favor the expansion of memory CD8(+) T cell subset, but inhibit the proliferation of CD8(+) T effector cells, possibly assuring their own survival. The recombinant proteins LirCyp1 and LirSOD are strongly recognized by memory cells of treated mice, indicating that these proteins

  7. Proliferating cell nuclear antigen (Pcna) as a direct downstream target gene of Hoxc8

    SciTech Connect

    Min, Hyehyun; Lee, Ji-Yeon; Bok, Jinwoong; Chung, Hyun Joo; Kim, Myoung Hee

    2010-02-19

    Hoxc8 is a member of Hox family transcription factors that play crucial roles in spatiotemporal body patterning during embryogenesis. Hox proteins contain a conserved 61 amino acid homeodomain, which is responsible for recognition and binding of the proteins onto Hox-specific DNA binding motifs and regulates expression of their target genes. Previously, using proteome analysis, we identified Proliferating cell nuclear antigen (Pcna) as one of the putative target genes of Hoxc8. Here, we asked whether Hoxc8 regulates Pcna expression by directly binding to the regulatory sequence of Pcna. In mouse embryos at embryonic day 11.5, the expression pattern of Pcna was similar to that of Hoxc8 along the anteroposterior body axis. Moreover, Pcna transcript levels as well as cell proliferation rate were increased by overexpression of Hoxc8 in C3H10T1/2 mouse embryonic fibroblast cells. Characterization of 2.3 kb genomic sequence upstream of Pcna coding region revealed that the upstream sequence contains several Hox core binding sequences and one Hox-Pbx binding sequence. Direct binding of Hoxc8 proteins to the Pcna regulatory sequence was verified by chromatin immunoprecipitation assay. Taken together, our data suggest that Pcna is a direct downstream target of Hoxc8.

  8. Speech recognition systems on the Cell Broadband Engine

    SciTech Connect

    Liu, Y; Jones, H; Vaidya, S; Perrone, M; Tydlitat, B; Nanda, A

    2007-04-20

    In this paper we describe our design, implementation, and first results of a prototype connected-phoneme-based speech recognition system on the Cell Broadband Engine{trademark} (Cell/B.E.). Automatic speech recognition decodes speech samples into plain text (other representations are possible) and must process samples at real-time rates. Fortunately, the computational tasks involved in this pipeline are highly data-parallel and can receive significant hardware acceleration from vector-streaming architectures such as the Cell/B.E. Identifying and exploiting these parallelism opportunities is challenging, but also critical to improving system performance. We observed, from our initial performance timings, that a single Cell/B.E. processor can recognize speech from thousands of simultaneous voice channels in real time--a channel density that is orders-of-magnitude greater than the capacity of existing software speech recognizers based on CPUs (central processing units). This result emphasizes the potential for Cell/B.E.-based speech recognition and will likely lead to the future development of production speech systems using Cell/B.E. clusters.

  9. Ubiquitinated Proteins Isolated From Tumor Cells Are Efficient Substrates for Antigen Cross-Presentation.

    PubMed

    Yu, Guangjie; Moudgil, Tarsem; Cui, Zhihua; Mou, Yongbin; Wang, Lixin; Fox, Bernard A; Hu, Hong-Ming

    2017-03-31

    We have previously shown that inhibition of the proteasome causes defective ribosomal products to be shunted into autophagosomes and subsequently released from tumor cells as defective ribosomal products in Blebs (DRibbles). These DRibbles serve as an excellent source of antigens for cross-priming of tumor-specific T cells. Here, we examine the role of ubiquitinated proteins (Ub-proteins) in this pathway. Using purified Ub-proteins from tumor cells that express endogenous tumor-associated antigen or exogenous viral antigen, we tested the ability of these proteins to stimulate antigen-specific T-cell responses, by activation of monocyte-derived dendritic cells generated from human peripheral blood mononuclear cells. Compared with total cell lysates, we found that purified Ub-proteins from both a gp100-specific melanoma cell line and from a lung cancer cell line expressing cytomegalovirus pp65 antigen produced a significantly higher level of IFN-γ in gp100- or pp65-specific T cells, respectively. In addition, Ub-proteins from an allogeneic tumor cell line could be used to stimulate tumor-infiltrating lymphocytes isolated and expanded from non-small cell lung cancer patients. These results establish that Ub-proteins provide a relevant source of antigens for cross-priming of antitumor immune responses in a variety of settings, including endogenous melanoma and exogenous viral antigen presentation, as well as antigen-specific tumor-infiltrating lymphocytes. Thus, ubiquitin can be used as an affinity tag to enrich for unknown tumor-specific antigens from tumor cell lysates to stimulate tumor-specific T cells ex vivo or to be used as vaccines to target short-lived proteins.

  10. A Lipid Based Antigen Delivery System Efficiently Facilitates MHC Class-I Antigen Presentation in Dendritic Cells to Stimulate CD8+ T Cells

    NASA Astrophysics Data System (ADS)

    Maji, Mithun; Mazumder, Saumyabrata; Bhattacharya, Souparno; Choudhury, Somsubhra Thakur; Sabur, Abdus; Shadab, Md.; Bhattacharya, Pradyot; Ali, Nahid

    2016-06-01

    The most effective strategy for protection against intracellular infections such as Leishmania is vaccination with live parasites. Use of recombinant proteins avoids the risks associated with live vaccines. However, due to low immunogenicity, they fail to trigger T cell responses particularly of CD8+ cells requisite for persistent immunity. Previously we showed the importance of protein entrapment in cationic liposomes and MPL as adjuvant for elicitation of CD4+ and CD8+ T cell responses for long-term protection. In this study we investigated the role of cationic liposomes on maturation and antigen presentation capacity of dendritic cells (DCs). We observed that cationic liposomes were taken up very efficiently by DCs and transported to different cellular sites. DCs activated with liposomal rgp63 led to efficient presentation of antigen to specific CD4+ and CD8+ T cells. Furthermore, lymphoid CD8+ T cells from liposomal rgp63 immunized mice demonstrated better proliferative ability when co-cultured ex vivo with stimulated DCs. Addition of MPL to vaccine enhanced the antigen presentation by DCs and induced more efficient antigen specific CD8+ T cell responses when compared to free and liposomal antigen. These liposomal formulations presented to CD8+ T cells through TAP-dependent MHC-I pathway offer new possibilities for a safe subunit vaccine.

  11. A Lipid Based Antigen Delivery System Efficiently Facilitates MHC Class-I Antigen Presentation in Dendritic Cells to Stimulate CD8(+) T Cells.

    PubMed

    Maji, Mithun; Mazumder, Saumyabrata; Bhattacharya, Souparno; Choudhury, Somsubhra Thakur; Sabur, Abdus; Shadab, Md; Bhattacharya, Pradyot; Ali, Nahid

    2016-06-02

    The most effective strategy for protection against intracellular infections such as Leishmania is vaccination with live parasites. Use of recombinant proteins avoids the risks associated with live vaccines. However, due to low immunogenicity, they fail to trigger T cell responses particularly of CD8(+) cells requisite for persistent immunity. Previously we showed the importance of protein entrapment in cationic liposomes and MPL as adjuvant for elicitation of CD4(+) and CD8(+) T cell responses for long-term protection. In this study we investigated the role of cationic liposomes on maturation and antigen presentation capacity of dendritic cells (DCs). We observed that cationic liposomes were taken up very efficiently by DCs and transported to different cellular sites. DCs activated with liposomal rgp63 led to efficient presentation of antigen to specific CD4(+) and CD8(+) T cells. Furthermore, lymphoid CD8(+) T cells from liposomal rgp63 immunized mice demonstrated better proliferative ability when co-cultured ex vivo with stimulated DCs. Addition of MPL to vaccine enhanced the antigen presentation by DCs and induced more efficient antigen specific CD8(+) T cell responses when compared to free and liposomal antigen. These liposomal formulations presented to CD8(+) T cells through TAP-dependent MHC-I pathway offer new possibilities for a safe subunit vaccine.

  12. Identification of novel Mycobacterium tuberculosis CD4 T-cell antigens via high throughput proteome screening

    PubMed Central

    Nayak, Kaustuv; Jing, Lichen; Russell, Ronnie M.; Davies, D. Huw; Hermanson, Gary; Molina, Douglas M.; Liang, Xiaowu; Sherman, David R.; Kwok, William W.; Yang, Junbao; Kenneth, John; Ahamed, Syed F.; Chandele, Anmol; Kaja, Murali-Krishna; Koelle, David M.

    2015-01-01

    Elicitation of CD4 IFN-gamma T cell responses to Mycobacterium tuberculosis (MTB) is a rational vaccine strategy to prevent clinical tuberculosis. Diagnosis of MTB infection is based on T-cell immune memory to MTB antigens. The MTB proteome contains over four thousand open reading frames (ORFs). We conducted a pilot antigen identification study using 164 MTB proteins and MTB-specific T-cells expanded in vitro from 12 persons with latent MTB infection. Enrichment of MTB-reactive T-cells from PBMC used cell sorting or an alternate system compatible with limited resources. MTB proteins were used as single antigens or combinatorial matrices in proliferation and cytokine secretion readouts. Overall, our study found that 44 MTB proteins were antigenic, including 27 not previously characterized as CD4 T-cell antigens. Antigen truncation, peptide, NTM homology, and HLA class II tetramer studies confirmed malate synthase G (encoded by gene Rv1837) as a CD4 T-cell antigen. This simple, scalable system has potential utility for the identification of candidate MTB vaccine and biomarker antigens. PMID:25857935

  13. Use of human antigen presenting cell gene array profiling to examine the effect of human T-cell leukemia virus type 1 Tax on primary human dendritic cells.

    PubMed

    Ahuja, Jaya; Kampani, Karan; Datta, Suman; Wigdahl, Brian; Flaig, Katherine E; Jain, Pooja

    2006-02-01

    Human T-cell leukemia virus type 1 (HTLV-1) is etiologically linked to adult T-cell leukemia and a progressive demyelinating disorder termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). One of the most striking features of the immune response in HAM/TSP centers on the expansion of HTLV-1-specific CD8(+) cytotoxic T lymphocyte (CTL) compartment in the peripheral blood and cerebrospinal fluid. More than 90% of the HTLV-1-specific CTLs are directed against the viral Tax (11-19) peptide implying that Tax is available for immune recognition by antigen presenting cells, such as dendritic cells (DCs). DCs obtained from HAM/TSP patients have been shown to be infected with HTLV-1 and exhibit rapid maturation. Therefore, we hypothesized that presentation of Tax peptides by activated DCs to naIve CD8(+) T cells may play an important role in the induction of a Tax-specific CTL response and neurologic dysfunction. In this study, a pathway-specific antigen presenting cell gene array was used to study transcriptional changes induced by exposure of monocyte-derived DCs to extracellular HTLV-1 Tax protein. Approximately 100 genes were differentially expressed including genes encoding toll-like receptors, cell surface receptors, proteins involved in antigen uptake and presentation and adhesion molecules. The differential regulation of chemokines and cytokines characteristic of functional DC activation was also observed by the gene array analyses. Furthermore, the expression pattern of signal transduction genes was also significantly altered. These results have suggested that Tax-mediated DC gene regulation might play a critical role in cellular activation and the mechanisms resulting in HTLV-1-induced disease.

  14. Censoring of self-reactive B cells by follicular dendritic cell-displayed self-antigen.

    PubMed

    Yau, Irene W; Cato, Matthew H; Jellusova, Julia; Hurtado de Mendoza, Tatiana; Brink, Robert; Rickert, Robert C

    2013-08-01

    In the secondary lymphoid organs, intimate contact with follicular dendritic cells (FDCs) is required for B cell retention and Ag-driven selection during the germinal center response. However, selection of self-reactive B cells by Ag on FDCs has not been addressed. To this end, we generated a mouse model to conditionally express a membrane-bound self-antigen on FDCs and to monitor the fate of developing self-reactive B cells. In this article, we show that self-antigen displayed on FDCs mediates effective elimination of self-reactive B cells at the transitional stage. Notwithstanding, some self-reactive B cells persist beyond this checkpoint, showing evidence of Ag experience and intact proximal BCR signaling, but they are short-lived and unable to elicit T cell help. These results implicate FDCs as an important component of peripheral B cell tolerance that prevents the emergence of naive B cells capable of responding to sequestered self-antigens.

  15. 20-kDa protein associated with the murine T-cell antigen receptor is phosphorylated in response to activation by antigen or concanavalin A

    SciTech Connect

    Samelson, L.E.; Harford, J.; Schwartz, R.H.; Klausner, R.D.

    1985-04-01

    Antigen or concanavalin A activation of a murine T-cell hybrid specific for pigeon cytochrome resulted in phosphorylation of a 20-kDa protein that was specifically coprecipitated by a monoclonal antibody binding the T-cell antigen receptor. There was no evidence for phosphorylation of the antigen receptor itself. The phosphorylation of the 20-kDa polypeptide was dependent on the concentration of antigen or lectin used to activate the T-cell hybrid and reached a maximum 40 min after the addition of antigen. The 20-kDa protein was also radioiodinated with a hydrophobic photoactivatable labeling reagent. The amount of iodinated 20-kDa protein immunoprecipitable with the anti-receptor antibody did not increase with T-cell activation, indicating that the phosphorylation occurred on a molecule that was constitutively associated with the antigen receptor. Concanavalin A also induced phosphorylation of a 20-kDa polypeptide in a second antigen-specific major histocompatibility complex-restricted T-cell hybrid. Again, the phosphorylated polypeptide was precipitated only by a monoclonal antibody specific for the antigen receptor on this hybrid. Thus, the antigen or concanavalin A-induced activation of T-cell hybrids results in the rapid phosphorylation of a 20-kDa protein that is associated with the T-cell receptor.

  16. Gamma delta T cells recognize a microbial encoded B Cell antigen to initiate a rapid antigen-specific Interleukin-17 response

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gamma delta T cells contribute uniquely to host immune defense, but the way in which they do so remains an enigma. Here we show that an algae protein, phycoerythrin (PE) is recognized by gamma delta T cells from mice, bovine and humans and binds directly to specific gamma delta T cell antigen recept...

  17. Human T cell activation. III. Induction of an early activation antigen, EA 1 by TPA, mitogens and antigens

    SciTech Connect

    Hara, T.; Jung, L.K.L.; FU, S.M.

    1986-03-01

    With human T cells activated for 12 hours by 12-o-tetradecanoyl phorbol-13-acetate (TPA) as immunogen, an IgG/sub 2a/ monoclonal antibody, mAb Ea 1, has been generated to a 60KD phosphorylated protein with 32KD and 28KD subunits. The antigen, Ea 1, is readily detected on 60% of isolated thymocytes by indirect immunofluorescence. A low level of Ea 1 expression is detectable on 2-6% of blood lymphocytes. Isolated T cells have been induced to express Ea 1 by TPA, mitogens and anitgens. TPA activated T cells express Ea 1 as early as 1 hour after activation. By 4 hours, greater than 95% of the T cells stain with mAb Ea 1. About 50% of the PHA or Con A activated T cells express Ea 1 with a similar kinetics. Ea 1 expression proceeds that of IL-2 receptor in these activation processes. T cells activated by soluble antigens (tetanus toxoid and PPD) and alloantigens in MLR also express Ea 1 after a long incubation. About 20% of the T cells stain for Ea 1 at day 6. Ea 1 expression is not limited to activated T cells. B cells activated by TPA or anti-IgM Ab plus B cell growth factor express Ea 1. The kinetics of Ea 1 expression is slower and the staining is less intense. Repeated attempts to detect Ea 1 on resting and activated monocytes and granulocytes have not been successful. Ea 1 expression is due to de novo synthesis for its induction is blocked by cycloheximide and actinomycin D. Ea 1 is the earliest activation antigen detectable to-date.

  18. Expression of T cell antigen receptor during differentiation

    SciTech Connect

    Allison, J.P.; Lanier, L.L.; Guyden, J.; Richie, E.R.

    1986-03-01

    The authors have used flow cytometry with monoclonal antibodies, radioimmuneprecipitation with a rabbit antiserum to common epitopes of the TCR, and Northern and Southern blot analysis with cloned TCR genes to study antigen receptor (TCR) expression by normal murine and human thymocytes and by primary murine thymomas. L3T4-,Lyt2- murine thymomas corresponding to the earliest stage of thymic differentiation, were found to have rearranged TCR beta genes, and to express low levels of beta transcript, but lacked alpha gene transcript and failed to express TCR on the cell surface. L3T4+,Lyt2+ thymomas were variable, but the majority were found to contain significant levels of both alpha and beta transcripts and to express TCR at the cell surface. Similarly, alpha and beta transcripts and TCR protein were detected in sorted L3T4+,Lyt2+ murine thymocytes. Using three color fluorescence, the authors determined that app. 70% of human T4+T8+ thymocytes also expressed T3, a component of the TCR complex. These data indicate that in mouse and man expression of TCR occurs in the immature, or cortical, thymic population.

  19. Stem Cell Antigen-1 in Skeletal Muscle Function

    PubMed Central

    Bernstein, Harold S.; Samad, Tahmina; Cholsiripunlert, Sompob; Khalifian, Saami; Gong, Wenhui; Ritner, Carissa; Aurigui, Julian; Ling, Vivian; Wilschut, Karlijn J.; Bennett, Stephen; Hoffman, Julien; Oishi, Peter

    2013-01-01

    Stem cell antigen-1 (Sca-1) is a member of the Ly-6 multigene family encoding highly homologous, glycosyl-phosphatidylinositol-anchored membrane proteins. Sca-1 is expressed on muscle-derived stem cells and myogenic precursors recruited to sites of muscle injury. We previously reported that inhibition of Sca-1 expression stimulated myoblast proliferation in vitro and regulated the tempo of muscle repair in vivo. Despite its function in myoblast expansion during muscle repair, a role for Sca-1 in normal, post-natal muscle has not been thoroughly investigated. We systematically compared Sca-1-/- (KO) and Sca-1+/+ (WT) mice and hindlimb muscles to elucidate the tissue, contractile, and functional effects of Sca-1 in young and aging animals. Comparison of muscle volume, fibrosis, myofiber cross-sectional area, and Pax7+ myoblast number showed little differences between ages or genotypes. Exercise protocols, however, demonstrated decreased stamina in KO versus WT mice, with young KO mice achieving results similar to aging WT animals. In addition, KO mice did not improve with practice, while WT animals demonstrated conditioning over time. Surprisingly, myomechanical analysis of isolated muscles showed that KO young muscle generated more force and experienced less fatigue. However, KO muscle also demonstrated incomplete relaxation with fatigue. These findings suggest that Sca-1 is necessary for muscle conditioning with exercise, and that deficient conditioning in Sca-1 KO animals becomes more pronounced with age. PMID:24042315

  20. Germ tube-specific antigens of Candida albicans cell walls

    SciTech Connect

    Sundstrom, P.R.

    1986-01-01

    Studies were performed to characterize the surface differences between blastospores and germ tubes of the pathogenic, dimorphic yeast, Candida albicans, and to identify components of yeast cells responsible for these differences. Investigation of surfaces differences of the two growth forms was facilitated by the production of rabbit antiserum prepared against Formalin-treated yeast possessing germ tubes. To prepare antiserum specific for germ tubes, this serum was adsorbed with stationary phase blastospores. Whereas the unadsorbed antiserum reacted with both blastospore and germ tube forms by immunofluorescence and Enzyme-Linked Immunosorbent Assay, the adsorbed antiserum did not react with blastospores but detected germ tube-specific antigens in hyphal forms. The differences between blastospores and germ tubes of Candida albicans, were further studied by comparing enzymatic digests of cell walls of both growth forms in radiolabeled organisms. Organisms were labeled either on the surface with /sup 125/I, or metabolically with (/sup 35/S) methionine or (/sup 3/H) mannose. Three-surface-located components (as shown by antibody adsorption and elution experiments) were precipitated from Zymolase digests. All three components were mannoproteins as shown by their ability to bind Concanavalin A, and to be labeled in protein labeling procedures, and two of these (200,000 and 155,000 molecular weight) were germ tube specific, as shown by their ability to be precipitated by germ tube-specific antiserum. Monoclonal antibodies were prepared to C. albicans, using blastospores bearing germ tubes as immunogen.

  1. Definition of target antigens for naturally occurring CD4(+) CD25(+) regulatory T cells.

    PubMed

    Nishikawa, Hiroyoshi; Kato, Takuma; Tawara, Isao; Saito, Kanako; Ikeda, Hiroaki; Kuribayashi, Kagemasa; Allen, Paul M; Schreiber, Robert D; Sakaguchi, Shimon; Old, Lloyd J; Shiku, Hiroshi

    2005-03-07

    The antigenic targets recognized by naturally occurring CD4(+) CD25(+) regulatory T cells (T reg cells) have been elusive. We have serologically defined a series of broadly expressed self-antigens derived from chemically induced mouse sarcomas by serological identification of antigens by recombinant expression cloning (SEREX). CD4(+) CD25(+) T cells from mice immunized with SEREX-defined self-antigens had strong suppressive activity on peptide-specific proliferation of CD4(+) CD25(-) T cells and CD8(+) T cells. The suppressive effect was observed without in vitro T cell stimulation. Foxp3 expression in these CD4(+) CD25(+) T cells from immunized mice was 5-10 times greater than CD4(+) CD25(+) T cells derived from naive mice. The suppressive effect required cellular contact and was blocked by anti-glucocorticoid-induced tumor necrosis factor receptor family-related gene antibody. In vitro suppressive activity essentially disappeared 8 wk after the last immunization. However, it was regained by in vitro restimulation with cognate self-antigen protein but not with control protein. We propose that SEREX-defined self-antigens such as those used in this study represent self-antigens that elicit naturally occurring CD4(+) CD25(+) T reg cells.

  2. Structural Basis for Antigen Recognition by Transglutaminase 2-specific Autoantibodies in Celiac Disease*

    PubMed Central

    Chen, Xi; Hnida, Kathrin; Graewert, Melissa Ann; Andersen, Jan Terje; Iversen, Rasmus; Tuukkanen, Anne; Svergun, Dmitri; Sollid, Ludvig M.

    2015-01-01

    Antibodies to the autoantigen transglutaminase 2 (TG2) are a hallmark of celiac disease. We have studied the interaction between TG2 and an anti-TG2 antibody (679-14-E06) derived from a single gut IgA plasma cell of a celiac disease patient. The antibody recognizes one of four identified epitopes targeted by antibodies of plasma cells of the disease lesion. The binding interface was identified by small angle x-ray scattering, ab initio and rigid body modeling using the known crystal structure of TG2 and the crystal structure of the antibody Fab fragment, which was solved at 2.4 Å resolution. The result was confirmed by testing binding of the antibody to TG2 mutants by ELISA and surface plasmon resonance. TG2 residues Arg-116 and His-134 were identified to be critical for binding of 679-14-E06 as well as other epitope 1 antibodies. In contrast, antibodies directed toward the two other main epitopes (epitopes 2 and 3) were not affected by these mutations. Molecular dynamics simulations suggest interactions of 679-14-E06 with the N-terminal domain of TG2 via the CDR2 and CDR3 loops of the heavy chain and the CDR2 loop of the light chain. In addition there were contacts of the framework 3 region of the heavy chain with the catalytic domain of TG2. The results provide an explanation for the biased usage of certain heavy and light chain gene segments by epitope 1-specific antibodies in celiac disease. PMID:26160175

  3. Enhanced antigen-presenting capacity of cultured Langerhans' cells is associated with markedly increased expression of Ia antigen

    SciTech Connect

    Shimada, S.; Caughman, S.W.; Sharrow, S.O.; Stephany, D.; Katz, S.I.

    1987-10-15

    Recent studies indicate that when epidermal Langerhans' cells (LC) are cultured for 2 to 3 days they, in comparison to freshly prepared LC, exhibit markedly enhanced ability to stimulate T cell proliferative responses in oxidative mitogenesis and in the mixed epidermal-leukocyte reaction. In this study, we determined whether cultured LC enhance antigen-specific T cell responses, and whether such enhanced stimulatory capacity correlates with the level of Ia antigen expressed on LC. We used C3H/He (Iak) epidermal cells as stimulators and, as responder cells, both the trinitrophenyl-specific clones D8 and SE4, which were assayed for (/sup 3/H)dThd incorporation, and the pigeon cytochrome c specific hybridoma 2C2, which was assayed for interleukin 2 production. Cultured LC induced 10 to 100 times greater proliferation or interleukin 2 production by responder cells than did freshly prepared LC. The intensity of I-Ak and I-Ek, expressed on cultured LC as assessed by immunofluorescence and flow cytometry, was found to be 10 to 36 times greater on a per cell basis than that on freshly prepared LC. Depletion of LC from fresh epidermal cell suspensions by anti-Iak and complement or treatment with 50 mJ/cm/sup 2/ medium range ultraviolet light or cycloheximide before culture abrogated both the increase in Ia expression and antigen-specific clonal proliferation. The results suggest that when LC are removed from their usual epidermal milieu, they express increased amounts of Ia and become more potent stimulators of T cell responses.

  4. Splenic B cells and antigen-specific B cells process anti-Ig in a similar manner

    SciTech Connect

    Myers, C.D.; Vitetta, E.S.

    1989-06-01

    B lymphocytes can process and present antigen to T cells. However, the fate of native antigen after its binding to specific B cells, i.e., the intracellular events involved in the processing and recycling of the antigenic fragments to the cell surface for antigen presentation, are not well understood. In the present study, we demonstrate that murine B cells degrade anti-Ig molecules bound to their surface and release acid soluble fragments into the supernatant. We also demonstrate that the kinetics of this process are identical for anti-mu, anti-delta, and anti-light chain antibodies, indicating that both surface IgM and surface IgD are equally effective in binding antigen and directing its processing. We also describe the effects of azide, chloroquine, and irradiation on this process. To extend these studies to the processing of specifically bound antigen, we demonstrate that highly purified trinitrophenyl antigen-binding cells degrade anti-Ig molecules with the same kinetics as unpurified splenic B cells. Thus, this purified population provides a suitable model system for the analysis of antigen degradation by antigen-specific cells.

  5. Cyclic re-entry of germinal center B cells in dealing with switching antigen

    NASA Astrophysics Data System (ADS)

    He, Chaoyang

    1999-08-01

    Germinal center spatial compartmentalization may help immune cells to optimize their mutation schedule so that affinity maturation through somatic hypermutation achieves higher efficiency. Some pathogens can alter their antigen expression (surface glycoprotein) by evolution of antigen or antigen switching or drifting to counteract the immune defense. We examine the switching antigen situation by introducing a prey-predator model in the string space representation of B cells and antigen, using Pontryagin's maximum principle to seek out the optimal mutation schedule, The optimal mutation schedule is still phase like. We conclude that re-entry of germinal center B cells is still crucial to affinity maturation. We further speculate a model of diffusing B cells coupling with pair correlation function may provide the underlying mechanism for the phasic like mutation schedule.

  6. Recognition of Histo-Blood Group Antigen-Like Carbohydrates in Lettuce by Human GII.4 Norovirus

    PubMed Central

    Gao, Xiang; Esseili, Malak A.; Lu, Zhongyan; Saif, Linda J.

    2016-01-01

    ABSTRACT Human norovirus (HuNoV) genogroup II genotype 4 (GII.4) strains account for about 80% of the gastroenteritis outbreaks in the United States. Contaminated food is a major transmission vehicle for this virus. In humans, pigs, and oysters, histo-blood group antigens (HBGAs) act as attachment factors for HuNoVs. In lettuce, although the virus-like particles (VLPs) of a GII.4 HuNoV were found to bind to cell wall carbohydrates, the exact binding site has not been investigated. Here, we show the presence of HBGA-like carbohydrates in the cell wall of lettuce. The digestion of lettuce leaves with cell wall-degrading enzymes exposed more binding sites and significantly increased the level of binding of GII.4 HuNoV VLPs. Competition assays showed that both the HBGA monoclonal antibody, recognizing the H type, and plant lectins, recognizing α-l-fucose in the H type, effectively inhibited VLP binding to lettuce tissues. Lettuce cell wall components were isolated and their NoV VLP binding characteristics were tested by enzyme-linked immunosorbent assays. The binding was inhibited by pretreatment of the lettuce cell wall materials with α-1,2-fucosidase. Collectively, our results indicate that H-type HBGA-like carbohydrates exist in lettuce tissues and that GII.4 HuNoV VLPs can bind the exposed fucose moiety, possibly in the hemicellulose component of the cell wall. IMPORTANCE Salad crops and fruits are increasingly recognized as vehicles for human norovirus (HuNoV) transmission. A recent study showed that HuNoVs specifically bind to the carbohydrates of the lettuce cell wall. Histo-blood group antigens (HBGAs) are carbohydrates and are known as the attachment factors for HuNoV infection in humans. In this study, we show the presence of HBGA-like carbohydrates in lettuce, to which HuNoVs specifically bind. These results suggest that specifically bound HuNoVs cannot be removed by simple washing, which may allow viral transmission to consumers. Our findings provide new

  7. Monitoring human leukocyte antigen class I molecules by micro-Raman spectroscopy at single-cell level

    NASA Astrophysics Data System (ADS)

    Das, Gobind; La Rocca, Rosanna; Lakshmikanth, Tadepally; Gentile, Francesco; Tallerico, Rossana; Zambetti, Lia P.; Devitt, J.; Candeloro, Patrizio; de Angelis, Francesco; Carbone, Ennio; di Fabrizio, Enzo

    2010-03-01

    Human leukocyte antigen (HLA) class I molecules are formed by three immunoglobulin-like domains (α1, α2, and α3) once folded by peptide and β2-microglobulin show the presence of two α-helix streams and one β-sheet limiting the pocket for the antigenic peptide. The loss of HLA class I expression in tumors and virus-infected cells, on one hand, prevents T cell recognition, while on the other hand, it leads to natural killer (NK) cell mediated cytotoxicity. We propose the possibility of using Raman spectroscopy to measure the relative expression of HLA class I molecules at the single-cell level. Raman spectra are recorded for three cell lines (K562, T2, and T3) and monomers (HLA class I folded, unfolded and peptide+β2-microlobulin refolded) using 830 nm laser line. Our data are consistent with the hypothesis that in the Raman spectra, ranging from 1600 to 1800 cm-1, the intensity variation of cells associated with HLA class I molecules could be measured.

  8. Chimeric antigen receptor (CAR)-specific monoclonal antibody to detect CD19-specific T cells in clinical trials.

    PubMed

    Jena, Bipulendu; Maiti, Sourindra; Huls, Helen; Singh, Harjeet; Lee, Dean A; Champlin, Richard E; Cooper, Laurence J N

    2013-01-01

    Clinical trials targeting CD19 on B-cell malignancies are underway with encouraging anti-tumor responses. Most infuse T cells genetically modified to express a chimeric antigen receptor (CAR) with specificity derived from the scFv region of a CD19-specific mouse monoclonal antibody (mAb, clone FMC63). We describe a novel anti-idiotype monoclonal antibody (mAb) to detect CD19-specific CAR(+) T cells before and after their adoptive transfer. This mouse mAb was generated by immunizing with a cellular vaccine expressing the antigen-recognition domain of FMC63. The specificity of the mAb (clone no. 136.20.1) was confined to the scFv region of the CAR as validated by inhibiting CAR-dependent lysis of CD19(+) tumor targets. This clone can be used to detect CD19-specific CAR(+) T cells in peripheral blood mononuclear cells at a sensitivity of 1∶1,000. In clinical settings the mAb is used to inform on the immunophenotype and persistence of administered CD19-specific T cells. Thus, our CD19-specific CAR mAb (clone no. 136.20.1) will be useful to investigators implementing CD19-specific CAR(+) T cells to treat B-lineage malignancies. The methodology described to develop a CAR-specific anti-idiotypic mAb could be extended to other gene therapy trials targeting different tumor associated antigens in the context of CAR-based adoptive T-cell therapy.

  9. Plasma-membrane-bound macromolecules are dynamically aggregated to form non-random codistribution patterns of selected functional elements. Do pattern recognition processes govern antigen presentation and intercellular interactions?

    PubMed

    Vereb, G; Mátyus, L; Bene, L; Panyi, G; Bacsó, Z; Balázs, M; Matkó, J; Szöllösi, J; Gáspár, R; Damjanovich, S

    1995-01-01

    Molecular recognition processes between cell surface elements are discussed with special reference to cell surface pattern formation of membrane-bound integral proteins. The existence, as detected by flow cytometric resonance energy transfer (Appendix), and significance of cell surface patterns involving the interleukin-2 receptor, the T-cell receptor-CD3 system, the intercellular adhesion molecule ICAM-1, and the major histocompatibility complex class I and class II molecules in the plasma membrane of lymphocytes are described. The modulation of antigen presentation by transmembrane potential changes is discussed, and a general role of transmembrane potential changes, and therefore of ion channel activities, adduced as one of the major regulatory mechanisms of cell-cell communication. A general role in the mediation and regulation of intercellular interactions is suggested for cell-surface macromolecular patterns. The dynamic pattern of protein and lipid molecules in the plasma membrane is generated by the genetic code, but has a remarkable flexibility and may be one of the major instruments of accommodation and recognition processes at the cellular level.

  10. Rapid screening and identification of dominant B cell epitopes of HBV surface antigen by quantum dot-based fluorescence polarization assay

    NASA Astrophysics Data System (ADS)

    Meng, Zhongji; Song, Ruihua; Chen, Yue; Zhu, Yang; Tian, Yanhui; Li, Ding; Cui, Daxiang

    2013-03-01

    A method for quickly screening and identifying dominant B cell epitopes was developed using hepatitis B virus (HBV) surface antigen as a target. Eleven amino acid fragments from HBV surface antigen were synthesized by 9-fluorenylmethoxy carbonyl solid-phase peptide synthesis strategy, and then CdTe quantum dots were used to label the N-terminals of all peptides. After optimizing the factors for fluorescence polarization (FP) immunoassay, the antigenicities of synthetic peptides were determined by analyzing the recognition and combination of peptides and standard antibody samples. The results of FP assays confirmed that 10 of 11 synthetic peptides have distinct antigenicities. In order to screen dominant antigenic peptides, the FP assays were carried out to investigate the antibodies against the 10 synthetic peptides of HBV surface antigen respectively in 159 samples of anti-HBV surface antigen-positive antiserum. The results showed that 3 of the 10 antigenic peptides may be immunodominant because the antibodies against them existed more widely among the samples and their antibody titers were higher than those of other peptides. Using three dominant antigenic peptides, 293 serum samples were detected for HBV infection by FP assays; the results showed that the antibody-positive ratio was 51.9% and the sensitivity and specificity were 84.3% and 98.2%, respectively. In conclusion, a quantum dot-based FP assay is a very simple, rapid, and convenient method for determining immunodominant antigenic peptides and has great potential in applications such as epitope mapping, vaccine designing, or clinical disease diagnosis in the future.

  11. Immunohistochemical detection of major histocompatibility complex antigens and quantitative analysis of tumour-infiltrating mononuclear cells in renal cell cancer.

    PubMed Central

    Tomita, Y.; Nishiyama, T.; Fujiwara, M.; Sato, S.

    1990-01-01

    In order to investigate the anti-tumour immune responsiveness of patients with renal cell cancer (RCC), we examined 30 such patients for the degree of expression of major histocompatibility complex (MHC) class I and class II antigens on RCC and the populations of tumour-infiltrating mononuclear cells (TIM). Normal renal tubular cells expressed class I but not class II antigens. Most of the tumour cells expressed class I antigens in 25 (83%) cases, but the proportion of such cells was reduced in five cases, three of which were of granular cell type histologically. Class II antigens were detected in all specimens with class I positivity. Various numbers of TIM were detected in 25 cases, being composed mainly of T cells and a smaller number of macrophages. Examination for the phenotype of T cells showed that CD8-positive cells were the dominant population. B cells were not detected. Quantitative analysis revealed that the numbers of TIM were significantly lower in cases showing class I reduction than in those with normal class I expression. Therefore, it was clear that class I antigens were preserved in RCC cells in most cases. Furthermore, a higher rate of reduction of class I antigens was observed in cases of granular cell type, which has been reported to have a worse prognosis than the clear cell type. The present data suggest that degree of the expression of MHC class I antigen on RCC might influence the host immune responsiveness against it. Images Figure 1 Figure 2 Figure 3 PMID:2206942

  12. Potent antigen-specific immune response induced by infusion of spleen cells coupled with succinimidyl-4-(N-maleimidomethyl cyclohexane)-1-carboxylate (SMCC) conjugated antigens.

    PubMed

    Guo, Yixian; Werbel, Tyler; Wan, Suigui; Wu, Haitao; Li, Yaohua; Clare-Salzler, Michael; Xia, Chang-Qing

    2016-02-01

    In the present study, we report our recently developed new approach to inducing antigen-specific immune response. We use two nucleophilic substitution "click" chemistry processes to successfully couple protein antigens or peptides to mouse spleen cells or T cells by a heterobifunctional crosslinker, succinimidyl-4-(N-maleimidomethyl cyclohexane)-1-carboxylate (SMCC) or sulfo-SMCC. SMCC and its water-soluble analog sulfo-SMCC contain N-hydroxysuccinimide (NHS) ester and maleimide groups, which allow stable covalent conjugation of amine- and sulfhydryl-containing molecules in trans. Protein coupling to cells relies on the free sulfhydryls (thiols) on cell surfaces and the free amines on protein antigens. Although the amount of protein coupled to cells is limited due to the limited number of cell surface thiols, the injection of spleen cells coupled with antigenic proteins, such as keyhole limpet hemocyanin (KLH) or ovalbumin (OVA), induces a potent antigen-specific immune response in vivo, which is even stronger than that induced by the injection of a large dose of protein plus adjuvants. In addition, short peptides coupled to purified splenic T cells also potently elicit peptide-specific T cell proliferation in vivo after injection. Further studies show that antigen-coupled spleen cell treatment leads to augmented IFN-γ-producing T cells. Our study provides a unique antigen delivery method that efficiently distributes antigen to the entire immune system, subsequently eliciting a potent antigen-specific immune response with enhanced IFN-γ production. The findings in the present study suggest that this antigen-cell coupling strategy could be employed in immunotherapy for cancers, infectious diseases as well as immune-mediated disorders.

  13. Detecting Antigen-Specific T Cell Responses: From Bulk Populations to Single Cells.

    PubMed

    Phetsouphanh, Chansavath; Zaunders, John James; Kelleher, Anthony Dominic

    2015-08-12

    A new generation of sensitive T cell-based assays facilitates the direct quantitation and characterization of antigen-specific T cell responses. Single-cell analyses have focused on measuring the quality and breadth of a response. Accumulating data from these studies demonstrate that there is considerable, previously-unrecognized, heterogeneity. Standard assays, such as the ICS, are often insufficient for characterization of rare subsets of cells. Enhanced flow cytometry with imaging capabilities enables the determination of cell morphology, as well as the spatial localization of the protein molecules within a single cell. Advances in both microfluidics and digital PCR have improved the efficiency of single-cell sorting and allowed multiplexed gene detection at the single-cell level. Delving further into the transcriptome of single-cells using RNA-seq is likely to reveal the fine-specificity of cellular events such as alternative splicing (i.e., splice variants) and allele-specific expression, and will also define the roles of new genes. Finally, detailed analysis of clonally related antigen-specific T cells using single-cell TCR RNA-seq will provide information on pathways of differentiation of memory T cells. With these state of the art technologies the transcriptomics and genomics of Ag-specific T cells can be more definitively elucidated.

  14. Detecting Antigen-Specific T Cell Responses: From Bulk Populations to Single Cells

    PubMed Central

    Phetsouphanh, Chansavath; Zaunders, John James; Kelleher, Anthony Dominic

    2015-01-01

    A new generation of sensitive T cell-based assays facilitates the direct quantitation and characterization of antigen-specific T cell responses. Single-cell analyses have focused on measuring the quality and breadth of a response. Accumulating data from these studies demonstrate that there is considerable, previously-unrecognized, heterogeneity. Standard assays, such as the ICS, are often insufficient for characterization of rare subsets of cells. Enhanced flow cytometry with imaging capabilities enables the determination of cell morphology, as well as the spatial localization of the protein molecules within a single cell. Advances in both microfluidics and digital PCR have improved the efficiency of single-cell sorting and allowed multiplexed gene detection at the single-cell level. Delving further into the transcriptome of single-cells using RNA-seq is likely to reveal the fine-specificity of cellular events such as alternative splicing (i.e., splice variants) and allele-specific expression, and will also define the roles of new genes. Finally, detailed analysis of clonally related antigen-specific T cells using single-cell TCR RNA-seq will provide information on pathways of differentiation of memory T cells. With these state of the art technologies the transcriptomics and genomics of Ag-specific T cells can be more definitively elucidated. PMID:26274954

  15. Prostate Stem Cell Antigen DNA Vaccination Breaks Tolerance to Self-antigen and Inhibits Prostate Cancer Growth

    PubMed Central

    Ahmad, Sarfraz; Casey, Garrett; Sweeney, Paul; Tangney, Mark; O'Sullivan, Gerald C

    2009-01-01

    Prostate stem cell antigen (PSCA) is a cell surface antigen expressed in normal human prostate and over expressed in prostate cancer. Elevated levels of PSCA protein in prostate cancer correlate with increased tumor stage/grade, with androgen independence and have higher expression in bone metastases. In this study, the PSCA gene was isolated from the transgenic adenocarcinoma mouse prostate cell line (TRAMPC1), and a vaccine plasmid construct was generated. This plasmid PSCA (pmPSCA) was delivered by intramuscular electroporation (EP) and induced effective antitumor immune responses against subcutaneous TRAMPC1 tumors in male C57 BL/6 mice. The pmPSCA vaccination inhibited tumor growth, resulting in cure or prolongation in survival. Similarly, the vaccine inhibited metastases in PSCA expressing B16 F10 tumors. There was activation of Th-1 type immunity against PSCA, indicating the breaking of tolerance to a self-antigen. This immunity was tumor specific and was transferable by adoptive transfer of splenocytes. The mice remained healthy and there was no evidence of collateral autoimmune responses in normal tissues. EP-assisted delivery of the pmPSCA evoked strong specific responses and could, in neoadjuvant or adjuvant settings, provide a safe and effective immune control of prostate cancer, given that there is significant homology between human and mouse PSCA. PMID:19337234

  16. Intestinal antigen-presenting cells in mucosal immune homeostasis: crosstalk between dendritic cells, macrophages and B-cells.

    PubMed

    Mann, Elizabeth R; Li, Xuhang

    2014-08-07

    The intestinal immune system maintains a delicate balance between immunogenicity against invading pathogens and tolerance of the commensal microbiota. Inflammatory bowel disease (IBD) involves a breakdown in tolerance towards the microbiota. Dendritic cells (DC), macrophages (MΦ) and B-cells are known as professional antigen-presenting cells (APC) due to their specialization in presenting processed antigen to T-cells, and in turn shaping types of T-cell responses generated. Intestinal DC are migratory cells, unique in their ability to generate primary T-cell responses in mesenteric lymph nodes or Peyer's patches, whilst MΦ and B-cells contribute to polarization and differentiation of secondary T-cell responses in the gut lamina propria. The antigen-sampling function of gut DC and MΦ enables them to sample bacterial antigens from the gut lumen to determine types of T-cell responses generated. The primary function of intestinal B-cells involves their secretion of large amounts of immunoglobulin A, which in turn contributes to epithelial barrier function and limits immune responses towards to microbiota. Here, we review the role of all three types of APC in intestinal immunity, both in the steady state and in inflammation, and how these cells interact with one another, as well as with the intestinal microenvironment, to shape mucosal immune responses. We describe mechanisms of maintaining intestinal immune tolerance in the steady state but also inappropriate responses of APC to components of the gut microbiota that contribute to pathology in IBD.

  17. Rapid desensitization induces internalization of antigen-specific IgE on mouse mast cells

    PubMed Central

    Oka, Tatsuya; Rios, Eon J.; Tsai, Mindy; Kalesnikoff, Janet; Galli, Stephen J.

    2013-01-01

    Background Rapid desensitization transiently prevents severe allergic reactions, allowing administration of life-saving therapies in previously sensitized patients. However, the mechanisms underlying successful rapid desensitization are not fully understood. Objectives We sought to investigate whether the mast cell (MC) is an important target of rapid desensitization in mice sensitized to exhibit IgE-dependent passive systemic anaphylaxis in vivo and to investigate the antigen specificity and underlying mechanisms of rapid desensitization in our mouse model. Methods C57BL/6 mice (in vivo) or primary isolated C57BL/6 mouse peritoneal mast cells (PMCs; in vitro) were passively sensitized with antigen-specific anti–2,4-dinitrophenyl IgE, anti-ovalbumin IgE, or both. MCs were exposed over a short period of time to increasing amounts of antigen (2,4-dinitrophenyl–human serum albumin or ovalbumin) in the presence of extracellular calcium in vitro or by means of intravenous administration to sensitized mice in vivo before challenging the mice with or exposing the PMCs to optimal amounts of specific or irrelevant antigen. Results Rapidly exposing mice or PMCs to progressively increasing amounts of specific antigen inhibited the development of antigen-induced hypothermia in sensitized mice in vivo and inhibited antigen-induced PMC degranulation and prostaglandin D2 synthesis in vitro. Such MC hyporesponsiveness was induced antigen-specifically and was associated with a significant reduction in antigen-specific IgE levels on MC surfaces. Conclusions Rapidly exposing MCs to progressively increasing amounts of antigen can both enhance the internalization of antigen-specific IgE on the MC surface and also desensitize these cells in an antigen-specific manner in vivo and in vitro. PMID:23810240

  18. Epstein-Barr virus nuclear antigen 2 specifically induces expression of the B-cell activation antigen CD23

    SciTech Connect

    Wang, F.; Gregory, C.D.; Rowe, M.; Rickinson, A.B.; Wang, D.; Birkenbach, M.; Kikutani, H.; Kishimoto, T.; Kieff, E.

    1987-05-01

    Epstein-Barr virus (EBV) infection of EBV-negative Burkitt lymphoma (BL) cells includes some changes similar to those seen in normal B lymphocytes that have been growth transformed by EBV. The role of individual EBV genes in this process was evaluated by introducing each of the viral genes that are normally expressed in EBV growth-transformed and latently infected lymphoblasts into an EBV-negative BL cell line, using recombinant retrovirus-mediated transfer. Clones of cells were derived that stably express the EBV nuclear antigen 1 (EBNA-1), EBNA-2, EBNA-3, EBNA-leader protein, or EBV latent membrane protein (LMP). These were compared with control clones infected with the retrovirus vector. All 10 clones converted to EBNA-2 expression differed from control clones or clones expressing other EBV proteins by growth in tight clumps and by markedly increased expression of one particular surface marker of B-cell activation, CD23. Other activation antigens were unaffected by EBNA-2 expression, as were markers already expressed on the parent BL cell line. The results indicate that EBNA-2 is a specific direct or indirect trans-activator of CD23. This establishes a link between an EBV gene and cell gene expression. Since CD23 has been implicated in the transduction of B-cell growth signals, its specific induction by EBNA-2 could be important in EBV induction of B-lymphocyte transformation.

  19. Stabilization of Transfected Cells Expressing Low-Incidence Blood Group Antigens: Novel Methods Facilitating Their Use as Reagent-Cells

    PubMed Central

    González, Cecilia; Esteban, Rosa; Canals, Carme; Muñiz-Díaz, Eduardo; Nogués, Núria

    2016-01-01

    Background The identification of erythrocyte antibodies in the serum of patients rely on panels of human red blood cells (RBCs), which coexpress many antigens and are not easily available for low-incidence blood group phenotypes. These problems have been addressed by generating cell lines expressing unique blood group antigens, which may be used as an alternative to human RBCs. However, the use of cell lines implies several drawbacks, like the requirement of cell culture facilities and the high cost of cryopreservation. The application of cell stabilization methods could facilitate their use as reagent cells in clinical laboratories. Methods We generated stably-transfected cells expressing low-incidence blood group antigens (Dia and Lua). High-expresser clones were used to assess the effect of TransFix® treatment and lyophilization as cell preservation methods. Cells were kept at 4°C and cell morphology, membrane permeability and antigenic properties were evaluated at several time-points after treatment. Results TransFix® addition to cell suspensions allows cell stabilization and proper antigen detection for at least 120 days, despite an increase in membrane permeability and a reduction in antigen expression levels. Lyophilized cells showed minor morphological changes and antigen expression levels were rather conserved at days 1, 15 and 120, indicating a high stability of the freeze-dried product. These stabilized cells have been proved to react specifically with human sera containing alloantibodies. Conclusions Both stabilization methods allow long-term preservation of the transfected cells antigenic properties and may facilitate their distribution and use as reagent-cells expressing low-incidence antigens, overcoming the limited availability of such rare RBCs. PMID:27603310

  20. Characterization of an antigen associated with the Marek's disease lymphoblastoid cell line MSB-1.

    PubMed

    Ross, L J

    1982-06-01

    A Marek's disease lymphoblastoid cell line (MSB-1) has been analysed by immunoprecipitation for expression of tumour-associated antigen, Marek's disease virus (MDV)-specific antigens and antigens specific to avian leukosis-sarcoma viruses. Rabbit antisera raised against two independently derived cell lines after extensive absorption with normal chick cells reacted with a polypeptide of mol. wt. 40 000 (40K) in extracts of MSB-1 cells. The 40K polypeptide was not present in myeloblasts or in chick embryo fibroblasts (CEF) infected with MDV and did not react with antiserum raised against normal chicken thymus antigens. The possibility that the 40K polypeptide is a tumour-associated antigen is discussed. Seven MDV-specific antigens were noted in infected CEF (mol. wt. 110K, 100K, 80K, 70K, 50K, 35K and 32K) but none of these was detected in MSB-1 cells. The avian leukosis-sarcoma group-specific antigen P27gag and its precursor Pr76gag were not found in MSB-1 cells, confirming that expression of mature gag protein is not required for transformation by MDV. However, two polypeptides of unknown origin and function (mol. wt. 180K and 110K) were precipitated from MSB-1 cells with a rabbit anti-Rous sarcoma (Schmidt-Rupin, subgroup D) antiserum.

  1. RNAi screen for kinases and phosphatases that play a role in antigen presentation by dendritic cells.

    PubMed

    Moita, Catarina F; Chora, Ângelo; Hacohen, Nir; Moita, Luis F

    2012-07-01

    Effective CD8(+) T-cell responses against tumor or microbial antigens that are not directly expressed in antigen-presenting cells (APCs) depend on the cross-presentation of these antigens on MHC class I in APCs. To identify signaling molecules that regulate cross-presentation, we used lentiviral-based RNA interference to test the roles of hundreds of kinases and phosphatases in this process. Our study uncovered eight previously unknown genes, consisting of one positive and seven negative regulators of antigen cross-presentation. Depletion of Acvr1c, a type I receptor for TGF-β family of signaling molecules, led to an increase in CD80 and CD86 co-stimulator surface expression and secreted IL-12 in mouse bone marrow-derived DCs, as well as antigen-specific T-cell proliferation.

  2. Gate-Level Commercial Microelectronics Verification with Standard Cell Recognition

    DTIC Science & Technology

    2015-03-26

    STANDARD CELL RECOGNITION THESIS Presented to the Faculty Department of Electrical and Computer Engineering Graduate School of Engineering and Management ...Tools . . . . . . 24 3.2 Phase 2 Methodology - Software Tool Application to Elementary Gates . . 25 3.3 Phase 3 Methodology - Software Tool...Implementation . . . . . . . . . . . . . . . . . 36 4.1.2 Phase 2 Results - Software Tool Application to Elementary Gates . 38 4.1.2.1 NAND2 Gate

  3. A DEPRESSION OF CELL-MEDIATED IMMUNITY TO MEASLES ANTIGEN IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

    PubMed Central

    Utermohlen, Virginia; Winfield, John B.; Zabriskie, John B.; Kunkel, Henry G.

    1974-01-01

    Using the direct migration inhibition test, response to measles antigen in patients with systemic lupus erythematosus (SLE) was found to be decreased when compared with that of normal subjects. No alteration was observed in similar experiments using parainfluenza type 1 and rubella antigens. The specific decrease in measles antigen effect showed no obvious correlation with activity of SLE or with the presence of lymphocytotoxic antibodies. Whether the specificity of the decrease in reactivity is due to some particular relationship between the measles virus or antigen and SLE, or to the possibility that measles reactivity is a more sensitive indicator of a generalized defect of cell-mediated immunity, remains unclear. PMID:4361242

  4. Increased sensitivity of antigen-experienced T cells through the enrichment of oligomeric T cell receptor complexes.

    PubMed

    Kumar, Rashmi; Ferez, María; Swamy, Mahima; Arechaga, Ignacio; Rejas, María Teresa; Valpuesta, Jose M; Schamel, Wolfgang W A; Alarcon, Balbino; van Santen, Hisse M

    2011-09-23

    Although memory T cells respond more vigorously to stimulation and they are more sensitive to low doses of antigen than naive T cells, the molecular basis of this increased sensitivity remains unclear. We have previously shown that the T cell receptor (TCR) exists as different-sized oligomers on the surface of resting T cells and that large oligomers are preferentially activated in response to low antigen doses. Through biochemistry and electron microscopy, we now showed that previously stimulated and memory T cells have more and larger TCR oligomers at the cell surface than their naive counterparts. Reconstitution of cells and mice with a point mutant of the CD3ζ subunit, which impairs TCR oligomer formation, demonstrated that the increased size of TCR oligomers was directly responsible for the increased sensitivity of antigen-experienced T cells. Thus, we propose that an "avidity maturation" mechanism underlies T cell antigenic memory.

  5. Dendritic Cells in the Periphery Control Antigen-Specific Natural and Induced Regulatory T Cells

    PubMed Central

    Yamazaki, Sayuri; Morita, Akimichi

    2013-01-01

    Dendritic cells (DCs) are specialized antigen-presenting cells that regulate both immunity and tolerance. DCs in the periphery play a key role in expanding naturally occurring Foxp3+ CD25+ CD4+ regulatory T cells (Natural T-regs) and inducing Foxp3 expression (Induced T-regs) in Foxp3− CD4+ T cells. DCs are phenotypically and functionally heterogeneous, and further classified into several subsets depending on distinct marker expression and their location. Recent findings indicate the presence of specialized DC subsets that act to expand Natural T-regs or induce Foxp3+ T-regs from Foxp3− CD4+ T cells. For example, two major subsets of DCs in lymphoid organs act differentially in inducing Foxp3+ T-regs from Foxp3− cells or expanding Natural T-regs with model-antigen delivery by anti-DC subset monoclonal antibodies in vivo. Furthermore, DCs expressing CD103 in the intestine induce Foxp3+ T-regs from Foxp3− CD4+ T cells with endogenous TGF-β and retinoic acid. In addition, antigen-presenting DCs have a capacity to generate Foxp3+ T-regs in the oral cavity where many antigens and commensals exist, similar to intestine and skin. In skin and skin-draining lymph nodes, at least six DC subsets have been identified, suggesting a complex DC-T-reg network. Here, we will review the specific activity of DCs in expanding Natural T-regs and inducing Foxp3+ T-regs from Foxp3− precursors, and further discuss the critical function of DCs in maintaining tolerance at various locations including skin and oral cavity. PMID:23801989

  6. Inclusion of Strep-Tag II in design of antigen receptors for T cell immunotherapy

    PubMed Central

    Liu, Lingfeng; Sommermeyer, Daniel; Cabanov, Alexandra; Kosasih, Paula; Hill, Tyler; Riddell, Stanley R

    2016-01-01

    The tactical introduction of Strep-tag II into synthetic antigen receptors provides engineered T cells with a marker for identification and rapid purification, and a functional element for selective antibody coated microbead-driven large-scale expansion. Such receptor designs can be applied to chimeric antigen receptors of different ligand specificities and costimulatory domains, and to T cell receptors to facilitate cGMP manufacturing of adoptive T cell therapies to treat cancer and other diseases. PMID:26900664

  7. Human epidermal Langerhans cells cointernalize by receptor-mediated endocytosis "nonclassical" major histocompatibility complex class I molecules (T6 antigens) and class II molecules (HLA-DR antigens).

    PubMed Central

    Hanau, D; Fabre, M; Schmitt, D A; Garaud, J C; Pauly, G; Tongio, M M; Mayer, S; Cazenave, J P

    1987-01-01

    HLA-DR and T6 surface antigens are expressed only by Langerhans cells and indeterminate cells in normal human epidermis. We have previously demonstrated that T6 antigens are internalized in Langerhans cells and indeterminate cells by receptor-mediated endocytosis. This process is induced by the binding of BL6, a monoclonal antibody directed against T6 antigens. In the present study, using a monoclonal antibody directed against HLA-DR antigens, on human epidermal cells in suspension, we show that the surface HLA-DR antigens are also internalized by receptor-mediated endocytosis in Langerhans and indeterminate cells. Moreover, using immunogold double labeling, we demonstrate that T6 and HLA-DR antigens are internalized through common coated regions of the membrane of Langerhans or indeterminate cells. The receptor-mediated endocytosis that is induced involves coated pits and vesicles, receptosomes, lysosomes, and also, in Langerhans cells, the Birbeck granules. Thus, T6 antigens, which are considered to be "unusual" or "nonclassical" major histocompatibility complex class I molecules, and the major histocompatibility complex class II molecules, HLA-DR, are internalized in Langerhans and indeterminate cells through common receptor-mediated endocytosis organelles. Images PMID:3106979

  8. Red Blood Cell Antigen Genotyping for Sickle Cell Disease, Thalassemia, and Other Transfusion Complications.

    PubMed

    Fasano, Ross M; Chou, Stella T

    2016-10-01

    Since the discovery of the ABO blood group in the early 20th century, more than 300 blood group antigens have been categorized among 35 blood group systems. The molecular basis for most blood group antigens has been determined and demonstrates tremendous genetic diversity, particularly in the ABO and Rh systems. Several blood group genotyping assays have been developed, and 1 platform has been approved by the Food and Drug Administration as a "test of record," such that no phenotype confirmation with antisera is required. DNA-based red blood cell (RBC) phenotyping can overcome certain limitations of hemagglutination assays and is beneficial in many transfusion settings. Genotyping can be used to determine RBC antigen phenotypes in patients recently transfused or with interfering allo- or autoantibodies, to resolve discrepant serologic typing, and/or when typing antisera are not readily available. Molecular RBC antigen typing can facilitate complex antibody evaluations and guide RBC selection for patients with sickle cell disease (SCD), thalassemia, and autoimmune hemolytic anemia. High-resolution RH genotyping can identify variant RHD and RHCE in patients with SCD, which have been associated with alloimmunization. In the future, broader access to cost-efficient, high-resolution RBC genotyping technology for both patient and donor populations may be transformative for the field of transfusion medicine.

  9. Selective culling of high avidity antigen-specific CD4+ T cells after virulent Salmonella infection.

    PubMed

    Ertelt, James M; Johanns, Tanner M; Mysz, Margaret A; Nanton, Minelva R; Rowe, Jared H; Aguilera, Marijo N; Way, Sing Sing

    2011-12-01

    Typhoid fever is a persistent infection caused by host-adapted Salmonella strains adept at circumventing immune-mediated host defences. Given the importance of T cells in protection, the culling of activated CD4+ T cells after primary infection has been proposed as a potential immune evasion strategy used by this pathogen. We demonstrate that the purging of activated antigen-specific CD4+ T cells after virulent Salmonella infection requires SPI-2 encoded virulence determinants, and is not restricted only to cells with specificity to Salmonella-expressed antigens, but extends to CD4+ T cells primed to expand by co-infection with recombinant Listeria monocytogenes. Unexpectedly, however, the loss of activated CD4+ T cells during Salmonella infection demonstrated using a monoclonal population of adoptively transferred CD4+ T cells was not reproduced among the endogenous repertoire of antigen-specific CD4+ T cells identified with MHC class II tetramer. Analysis of T-cell receptor variable segment usage revealed the selective loss and reciprocal enrichment of defined CD4+ T-cell subsets after Salmonella co-infection that is associated with the purging of antigen-specific cells with the highest intensity of tetramer staining. Hence, virulent Salmonella triggers the selective culling of high avidity activated CD4+ T-cell subsets, which re-shapes the repertoire of antigen-specific T cells that persist later after infection.

  10. Immunoregulatory adherent cells in human tuberculosis: radiation-sensitive antigen-specific suppression by monocytes

    SciTech Connect

    Kleinhenz, M.E.; Ellner, J.J.

    1985-07-01

    In human tuberculosis, adherent mononuclear cells (AMC) selectively depress in vitro responses to the mycobacterial antigen tuberculin purified protein derivative (PPD). The phenotype of this antigen-specific adherent suppressor cell was characterized by examining the functional activity of adherent cells after selective depletion of sheep erythrocyte-rosetting T cells or OKM1-reactive monocytes. Adherent cell suppression was studied in the (/sup 3/H)thymidine-incorporation microculture assay by using T cells rigorously depleted of T cells with surface receptors for the Fc portion of IgG (T gamma cells) as antigen-responsive cells. PPD-induced (/sup 3/H)thymidine incorporation by these non gamma T cells was uniformly reduced (mean, 42% +/- 10% (SD)) when autologous AMC were added to non gamma T cells at a ratio of 1:2. Antigen-specific suppression by AMC was not altered by depletion of sheep erythrocyte-rosetting T cells or treatment with indomethacin. However, AMC treated with OKM1 and complement or gamma irradiation (1,500 rads) no longer suppressed tuberculin responses in vitro. These studies identify the antigen-specific adherent suppressor cell in tuberculosis as an OKM1-reactive, non-erythrocyte-rosetting monocyte. The radiosensitivity of this monocyte immunoregulatory function may facilitate its further definition.

  11. Antigen availability determines CD8+ T cell-dendritic cell interaction kinetics and memory fate decisions

    PubMed Central

    Henrickson, Sarah E.; Stutte, Susanne; Quigley, Michael; Alexe, Gabriela; Iannacone, Matteo; Flynn, Michael P.; Omid, Shaida; Jesneck, Jonathan L.; Imam, Sabrina; Mempel, Thorsten R.; Mazo, Irina B.; Haining, William N.; von Andrian, Ulrich H.

    2014-01-01

    Summary T cells are activated by antigen (Ag) bearing dendritic cells (DCs) in lymph nodes in 3 phases. The duration of the initial phase of transient, serial DC-T cell interactions is inversely correlated with Ag dose. The second phase, characterized by stable DC-T cell contacts, is believed to be necessary for full-fledged T cell activation. Here we have shown that this is not the case. CD8+ T cells interacting with DCs presenting low-dose, short-lived Ag did not transition to phase 2, while higher Ag dose yielded phase 2 transition. Both antigenic constellations promoted T cell proliferation and effector differentiation, but yielded different transcriptome signatures at 12h and 24h. T cells that experienced phase 2 developed long-lived memory, whereas conditions without stable contacts yielded immunological amnesia. Thus, T cells make fate decisions within hours after Ag exposure resulting in long-term memory or abortive effector responses, correlating with T cell-DCs interaction kinetics. PMID:24054328

  12. Skin-Resident Antigen-Presenting Cells: Instruction Manual for Vaccine Development

    PubMed Central

    Fehres, Cynthia M.; Garcia-Vallejo, Juan J.; Unger, Wendy W. J.; van Kooyk, Yvette

    2013-01-01

    The induction of antigen-specific effector T cells is driven by proper antigen presentation and co-stimulation by dendritic cells (DCs). For this reason strategies have been developed to instruct DCs for the induction of CD4+ and CD8+ T cell responses. Since DCs are localized, amongst other locations, in peripheral tissues such as the skin, new vaccines are aiming at targeting antigens to DCs in situ. Optimal skin-DC targeting in combination with adequate adjuvant delivery facilitates DC maturation and migration to draining lymph nodes and enhances antigen cross-presentation and T cell priming. In this review we describe what DC subsets populate the human skin, as well as current vaccination strategies based on targeting strategies and alternative administration for the induction of robust long-lived anti-cancer effector T cells. PMID:23801994

  13. Chimeric antigen receptor T-cell neuropsychiatric toxicity in acute lymphoblastic leukemia.

    PubMed

    Prudent, Vasthie; Breitbart, William S

    2017-01-04

    Chimeric antigen receptor T cells are used in the treatment of B-cell leukemias. Common chimeric antigen receptor T-cell toxicities can range from mild flu-like symptoms, such as fever and myalgia, to a more striking neuropsychiatric toxicity that can present as discrete neurological symptoms and delirium. We report here two cases of chimeric antigen receptor T-cell neuropsychiatric toxicity, one who presented as a mild delirium and aphasia that resolved without intervention, and one who presented with delirium, seizures, and respiratory insufficiency requiring intensive treatment. The current literature on the treatment and proposed mechanisms of this clinically challenging chimeric antigen receptor T-cell complication is also presented.

  14. Cancer/testis antigens can be immunological targets in clonogenic CD133+ melanoma cells.

    PubMed

    Gedye, Craig; Quirk, Juliet; Browning, Judy; Svobodová, Suzanne; John, Thomas; Sluka, Pavel; Dunbar, P Rod; Corbeil, Denis; Cebon, Jonathan; Davis, Ian D

    2009-10-01

    "Cancer stem cells" that resist conventional treatments may be a cause of therapeutic failure in melanoma. We report a subpopulation of clonogenic melanoma cells that are characterized by high prominin-1/CD133 expression in melanoma and melanoma cell lines. These cells have enhanced clonogenicity and self-renewal in vitro, and serve as a limited in vitro model for melanoma stem cells. In some cases clonogenic CD133(+) melanoma cells show increased expression of some cancer/testis (CT) antigens. The expression of NY-ESO-1 in an HLA-A2 expressing cell line allowed CD133(+) clonogenic melanoma cells to be targeted for killing in vitro by NY-ESO-1-specific CD8(+) T-lymphocytes. Our in vitro findings raise the hypothesis that if melanoma stem cells express CT antigens in vivo that immune targeting of these antigens may be a viable clinical strategy for the adjuvant treatment of melanoma.

  15. CD8+NKT-like cells regulate the immune response by killing antigen-bearing DCs

    PubMed Central

    Wang, Chao; Liu, Xi; Li, Zhengyuan; Chai, Yijie; Jiang, Yunfeng; Wang, Qian; Ji, Yewei; Zhu, Zhongli; Wan, Ying; Yuan, Zhenglong; Chang, Zhijie; Zhang, Minghui

    2015-01-01

    CD1d-dependent NKT cells have been extensively studied; however, the function of CD8+NKT-like cells, which are CD1d-independent T cells with NK markers, remains unknown. Here, we report that CD1d-independent CD8+NKT-like cells, which express both T cell markers (TCRβ and CD3) and NK cell receptors (NK1.1, CD49b and NKG2D), are activated and significantly expanded in mice immunized with GFP-expressing dendritic cells. Distinct from CD1d-dependent NKT cells, CD8+NKT-like cells possess a diverse repertoire of TCRs and secrete high levels of IFN-gamma but not IL-4. CD8+NKT-like cell development is normal in CD1d−/− mice, which suggests that CD8+NKT-like cells undergo a unique development pathway that differs from iNKT cells. Further functional analyses show that CD8+NKT-like cells suppress T-cell responses through elimination of dendritic cells in an antigen-specific manner. Adoptive transfer of antigen-specific CD8+NKT-like cells into RIP-OVA mice prevented subsequent development of diabetes in the animals induced by activated OT-I CD8 T cells. Our study suggests that CD8+NKT-like cells can function as antigen-specific suppressive cells to regulate the immune response through killing antigen-bearing DCs. Antigen-specific down regulation may provide an active and precise method for constraining an excessive immune response and avoiding bypass suppression of necessary immune responses to other antigens. PMID:26369936

  16. Cell shape recognition by colloidal cell imprints: Energy of the cell-imprint interaction

    NASA Astrophysics Data System (ADS)

    Borovička, Josef; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2015-09-01

    The results presented in this study are aimed at the theoretical estimate of the interactions between a spherical microbial cell and the colloidal cell imprints in terms of the Derjaguin, Landau, Vervey, and Overbeek (DLVO) surface forces. We adapted the Derjaguin approximation to take into account the geometry factor in the colloidal interaction between a spherical target particle and a hemispherical shell at two different orientations with respect to each other. We took into account only classical DLVO surface forces, i.e., the van der Waals and the electric double layer forces, in the interaction of a spherical target cell and a hemispherical shell as a function of their size ratio, mutual orientation, distance between their surfaces, their respective surface potentials, and the ionic strength of the aqueous solution. We found that the calculated interaction energies are several orders higher when match and recognition between the target cell and the target cell imprint is achieved. Our analysis revealed that the recognition effect of the hemispherical shell towards the target microsphere comes from the greatly increased surface contact area when a full match of their size and shape is produced. When the interaction between the surfaces of the hemishell and the target cell is attractive, the recognition greatly amplifies the attraction and this increases the likelihood of them to bind strongly. However, if the surface interaction between the cell and the imprint is repulsive, the shape and size match makes this interaction even more repulsive and thus decreases the likelihood of binding. These results show that the surface chemistry of the target cells and their colloidal imprints is very important in controlling the outcome of the interaction, while the shape recognition only amplifies the interaction. In the case of nonmonotonous surface-to-surface interaction we discovered some interesting interplay between the effects of shape match and surface chemistry

  17. Structural analysis and unique molecular recognition properties of a Bauhinia forficata lectin that inhibits cancer cell growth.

    PubMed

    Lubkowski, Jacek; Durbin, Sarah V; Silva, Mariana C C; Farnsworth, David; Gildersleeve, Jeffrey C; Oliva, Maria Luiza V; Wlodawer, Alexander

    2017-02-01

    Lectins have been used at length for basic research and clinical applications. New insights into the molecular recognition properties enhance our basic understanding of carbohydrate-protein interactions and aid in the design/development of new lectins. In this study, we used a combination of cell-based assays, glycan microarrays, and X-ray crystallography to evaluate the structure and function of the recombinant Bauhinia forficata lectin (BfL). The lectin was shown to be cytostatic for several cancer cell lines included in the NCI-60 panel; in particular, it inhibited growth of melanoma cancer cells (LOX IMVI) by over 95%. BfL is dimeric in solution and highly specific for binding of oligosaccharides and glycopeptides with terminal N-acetylgalactosamine (GalNAc). BfL was found to have especially strong binding (apparent Kd  = 0.5-1.0 nm) to the tumor-associated Tn antigen. High-resolution crystal structures were determined for the ligand-free lectin, as well as for its complexes with three Tn glycopeptides, globotetraose, and the blood group A antigen. Extensive analysis of the eight crystal structures and comparison to structures of related lectins revealed several unique features of GalNAc recognition. Of special note, the carboxylate group of Glu126, lining the glycan-binding pocket, forms H-bonds with both the N-acetyl of GalNAc and the peptide amido group of Tn antigens. Stabilization provided by Glu126 is described here for the first time for any GalNAc-specific lectin. Taken together, the results provide new insights into the molecular recognition of carbohydrates and provide a structural understanding that will enable rational engineering of BfL for a variety of applications.

  18. Focused specificity of intestinal TH17 cells towards commensal bacterial antigens.

    PubMed

    Yang, Yi; Torchinsky, Miriam B; Gobert, Michael; Xiong, Huizhong; Xu, Mo; Linehan, Jonathan L; Alonzo, Francis; Ng, Charles; Chen, Alessandra; Lin, Xiyao; Sczesnak, Andrew; Liao, Jia-Jun; Torres, Victor J; Jenkins, Marc K; Lafaille, Juan J; Littman, Dan R

    2014-06-05

    T-helper-17 (TH17) cells have critical roles in mucosal defence and in autoimmune disease pathogenesis. They are most abundant in the small intestine lamina propria, where their presence requires colonization of mice with microbiota. Segmented filamentous bacteria (SFB) are sufficient to induce TH17 cells and to promote TH17-dependent autoimmune disease in animal models. However, the specificity of TH17 cells, the mechanism of their induction by distinct bacteria, and the means by which they foster tissue-specific inflammation remain unknown. Here we show that the T-cell antigen receptor (TCR) repertoire of intestinal TH17 cells in SFB-colonized mice has minimal overlap with that of other intestinal CD4(+) T cells and that most TH17 cells, but not other T cells, recognize antigens encoded by SFB. T cells with antigen receptors specific for SFB-encoded peptides differentiated into RORγt-expressing TH17 cells, even if SFB-colonized mice also harboured a strong TH1 cell inducer, Listeria monocytogenes, in their intestine. The match of T-cell effector function with antigen specificity is thus determined by the type of bacteria that produce the antigen. These findings have significant implications for understanding how commensal microbiota contribute to organ-specific autoimmunity and for developing novel mucosal vaccines.

  19. Identification of a cell-surface antigen selectively expressed on the natural killer cell

    PubMed Central

    1977-01-01

    We have studied the cell-surface phenotype of natural killer (NK) cells of NZB and B6 mice which react to an MuLV+ lymphoid tumor. (a) NK cells do not express Thy1, Ly2, or Ig surface markers. (b) NK cells express an antigen recognized by C3H anti-CE antiserum ('anti-Ly1.2 antiserum'). Inasmuch as NK activity of spleen cells from B6 and B6/Ly1.1 congenic strains were both equally sensitive to C3H anti-CE antiserum, the NK antigen is distinct from Ly1.2. This point was confirmed by the observation that alphaNK activity was removed by absorption of C3H anti-CE antiserum with spleen cells from either B6 or B6/Ly1.1 congenic strains. Absorption of C3H alphaCE serum with BALB/c thymocytes and spleen cells (which are Ly1.2+NK-) removed anti-Ly1.2 activity and left anti-NK activity intact. This absorption step could be circumvented by inserting the BALB/c genotype into the recipient immunized to CE cells (i.e., (C3H X BALB/c)F1 alphaCE spleen cells). This antiserum, provisionally termed 'anti-NK', defines a new subclass of lymphocytes which may play a central role in the immunosurveillance against tumors. PMID:187714

  20. Stage-specific embryonic antigen-4 identifies human dental pulp stem cells.

    PubMed

    Kawanabe, Noriaki; Murata, Satoko; Fukushima, Hiroaki; Ishihara, Yoshihito; Yanagita, Takeshi; Yanagita, Emmy; Ono, Mitsuaki; Kurosaka, Hiroshi; Kamioka, Hiroshi; Itoh, Tomoo; Kuboki, Takuo; Yamashiro, Takashi

    2012-03-10

    Embryonic stem cell-associated antigens are expressed in a variety of adult stem cells as well as embryonic stem cells. In the present study, we investigated whether stage-specific embryonic antigen (SSEA)-4 can be used to isolate dental pulp (DP) stem cells. DP cells showed plastic adherence, specific surface antigen expression, and multipotent differentiation potential, similar to mesenchymal stem cells (MSC). SSEA-4+ cells were found in cultured DP cells in vitro as well as in DP tissue in vivo. Flow cytometric analysis demonstrated that 45.5% of the DP cells were SSEA-4+. When the DP cells were cultured in the presence of all-trans-retinoic acid, marked downregulation of SSEA-3 and SSEA-4 and the upregulation of SSEA-1 were observed. SSEA-4+ DP cells showed a greater telomere length and a higher growth rate compared to ungated and SSEA-4- cells. A clonal assay demonstrated that 65.5% of the SSEA-4+ DP cells had osteogenic potential, and the SSEA-4+ clonal DP cells showed multilineage differentiation potential toward osteoblasts, chondrocytes, and neurons in vitro. In addition, the SSEA-4+ DP cells had the capacity to form ectopic bone in vivo. Thus, our results suggest that SSEA-4 is a specific cell surface antigen that can be used to identify DP stem cells.

  1. Host cell-induced components of the sulfate assimilation pathway are major protective antigens of Mycobacterium tuberculosis.

    PubMed

    Pinto, Rachel; Leotta, Lisa; Shanahan, Erin R; West, Nicholas P; Leyh, Thomas S; Britton, Warwick; Triccas, James A

    2013-03-01

    New therapies to control tuberculosis are urgently required because of the inability of the only available vaccine, BCG, to adequately protect against tuberculosis. Here we demonstrate that proteins of the Mycobacterium tuberculosis sulfate-assimilation pathway (SAP) represent major immunogenic targets of the bacillus, as defined by strong T-cell recognition by both mice and humans infected with M. tuberculosis. SAP proteins displayed increased expression when M. tuberculosis was resident within host cells, which may account in part for their ability to stimulate anti-M. tuberculosis host immunity. Vaccination with the first enzyme in this pathway, adenosine-5'-triphosphate sulfurylase, conferred significant protection against murine tuberculosis and boosted BCG-induced protective immunity in the lung. Therefore, we have identified SAP components as a new family of M. tuberculosis antigens, and we have demonstrated that these components are promising candidate for inclusion in new vaccines to control tuberculosis in humans.

  2. Circle Hough transform implementation for dots recognition in braille cells

    NASA Astrophysics Data System (ADS)

    Jacinto Gómez, Edwar; Montiel Ariza, Holman; Martínez Sarmiento, Fredy Hernán.

    2017-02-01

    This paper shows a technique based on CHT (Circle Hough Transform) to achieve the optical Braille recognition (OBR). Unlike other papers developed around the same topic, this one is made by using Hough Transform to process the recognition and transcription of Braille cells, proving CHT to be an appropriate technique to go over different non-systematics factors who can affect the process, as the paper type where the text to traduce is placed, some lightning factors, input image resolution and some flaws derived from the capture process, which is realized using a scanner. Tests are performed with a local database using text generated by visual nondisabled people and some transcripts by sightless people; all of this with the support of National Institute for Blind People (INCI for their Spanish acronym) placed in Colombia.

  3. Sequential induction of MHC antigens on autochthonous cells of ileum affected by Crohn's disease.

    PubMed Central

    Koretz, K.; Momburg, F.; Otto, H. F.; Möller, P.

    1987-01-01

    Changes were examined in the expression of Class I and II major histocompatibility complex (MHC) antigens by autochthonous cells of the terminal ileum affected by Crohn's disease. The study was based on the analysis of transmural specimens from terminal ileum segments obtained in the course of ileocolectomy for colon cancer and Crohn's disease. Serial sections were immunostained using monoclonal antibodies directed against monomorphic determinants of HLA-A,B,C, DR, DP, DQ, and the invariant chain (Ii) associated with Class II molecules. Compared with the normal state, the only change in Class I antigen expression occurring in Crohn's disease was the induction of HLA-A,B,C antigens in lymphatic endothelium. Changes in Class II antigen expression were more substantial. Enhancement of HLA-DR expression was found in enterocytes; DR induction was observed in glial cells of the visceral nervous plexus and in venular and venous endothelium. HLA-DP and DQ antigens were induced in enterocytes, glial cells, and capillary and venular endothelium, although this induction was restricted to areas of moderate or high inflammatory activity. The tissue distribution of Ii closely resembled that of HLA-DR, although this association was not strict: on the one hand, arterial endothelium contained low amounts of Ii in the absence of DR antigens; on the other hand, glial cells expressed Class II molecules in the absence of Ii. The extent of local enhancement/induction of MHC antigens was positively correlated with the local density of the cellular infiltrate. These data suggest that altered MHC antigen expression by autochthonous structures might be mediated by factors released from the lymphohistiocytic infiltrate, which is itself attracted by an unknown signal. In conjunction with an unknown antigen, the enhanced expression of Class II antigens might trigger an autoaggressive immune response. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:3425689

  4. The PANE1 gene encodes a novel human minor histocompatibility antigen that is selectively expressed in B-lymphoid cells and B-CLL

    PubMed Central

    Brickner, Anthony G.; Evans, Anne M.; Mito, Jeffrey K.; Xuereb, Suzanne M.; Feng, Xin; Nishida, Tetsuya; Fairfull, Liane; Ferrell, Robert E.; Foon, Kenneth A.; Hunt, Donald F.; Shabanowitz, Jeffrey; Engelhard, Victor H.; Riddell, Stanley R.; Warren, Edus H.

    2006-01-01

    Minor histocompatibility antigens (mHAg's) are peptides encoded by polymorphic genes that are presented by major histocompatibility complex (MHC) molecules and recognized by T cells in recipients of allogeneic hematopoietic cell transplants. Here we report that an alternative transcript of the proliferation-associated nuclear element 1 (PANE1) gene encodes a novel human leukocyte antigen (HLA)-A*0301-restricted mHAg that is selectively expressed in B-lymphoid cells. The antigenic peptide is entirely encoded within a unique exon not present in other PANE1 transcripts. Sequencing of PANE1 alleles in mHAg-positive and mHAg-negative cells demonstrates that differential T-cell recognition is due to a single nucleotide polymorphism within the variant exon that replaces an arginine codon with a translation termination codon. The PANE1 transcript that encodes the mHAg is expressed at high levels in resting CD19+ B cells and B-lineage chronic lymphocytic leukemia (B-CLL) cells, and at significantly lower levels in activated B cells. Activation of B-CLL cells through CD40 ligand (CD40L) stimulation decreases expression of the mHAg-encoding PANE1 transcript and reciprocally increases expression of PANE1 transcripts lacking the mHAg-encoding exon. These studies suggest distinct roles for different PANE1 isoforms in resting compared with activated CD19+ cells, and identify PANE1 as a potential therapeutic target in B-CLL. PMID:16391015

  5. Investigation of red blood cell antigens with highly fluorescent and stable semiconductor quantum dots.

    PubMed

    de Farias, Patrícia Maria Albuquerque; Santos, Beate Saegesser; de Menezes, Frederico Duarte; de Carvalho Ferreira, Ricardo; Barjas-Castro, Maria Lourdes; Castro, Vagner; Lima, Paulo Roberto Moura; Fontes, Adriana; Cesar, Carlos Lenz

    2005-01-01

    We report a new methodology for red blood cell antigen expression determination by a simple labeling procedure employing luminescent semiconductor quantum dots. Highly luminescent and stable core shell cadmium sulfide/cadmium hydroxide colloidal particles are obtained, with a predominant size of 9 nm. The core-shell quantum dots are functionalized with glutaraldehyde and conjugated to a monoclonal anti-A antibody to target antigen-A in red blood cell membranes. Erythrocyte samples of blood groups A+, A2+, and O+ are used for this purpose. Confocal microscopy images show that after 30 min of conjugation time, type A+ and A2+ erythrocytes present bright emission, whereas the O+ group cells show no emission. Fluorescence intensity maps show different antigen expressions for the distinct erythrocyte types. The results obtained strongly suggest that this simple labeling procedure may be employed as an efficient tool to investigate quantitatively the distribution and expression of antigens in red blood cell membranes.

  6. Some aspects of oncogenic virus-host cell and virus-tumor cell antigenic relationships.

    PubMed

    Nastac, E

    1982-01-01

    Some viewpoints are presented as regards the virus-host cell relationship within the framework of carcinogenesis. Data are reviewed which point out the possibility of the transfer of cellular antigenic fractions from the tumor cell to the virus that grows in it, as well as of a hybridization between the virus genome and the genome of the tumoral host cell. Such a hybridization may have multiple consequences, among which the appearance of new oncogenic variants of viruses so far known to be nononcogenic ones.

  7. B lymphocytes as direct antigen-presenting cells for anti-tumor DNA vaccines

    PubMed Central

    Colluru, Viswa Teja; McNeel, Douglas G.

    2016-01-01

    In spite of remarkable preclinical efficacy, DNA vaccination has demonstrated low immunogenicity in humans. While efforts have focused on increasing cross-presentation of DNA-encoded antigens, efforts to increase DNA vaccine immunogenicity by targeting direct presentation have remained mostly unexplored. In these studies, we compared the ability of different APCs to present antigen to T cells after simple co-culture with plasmid DNA. We found that human primary peripheral B lymphocytes, and not monocytes or in vitro derived dendritic cells (DCs), were able to efficiently encode antigen mRNA and expand cognate tumor antigen-specific CD8 T cells ex vivo. Similarly, murine B lymphocytes co-cultured with plasmid DNA, and not DCs, were able to prime antigen-specific T cells in vivo. Moreover, B lymphocyte-mediated presentation of plasmid antigen led to greater Th1-biased immunity and was sufficient to elicit an anti-tumor effect in vivo. Surprisingly, increasing plasmid presentation by B cells, and not cross presentation of peptides by DCs, further augmented traditional plasmid vaccination. Together, these data suggest that targeting plasmid DNA to B lymphocytes, for example through transfer of ex vivo plasmidloaded B cells, may be novel means to achieve greater T cell immunity from DNA vaccines. PMID:27661128

  8. Tandem CAR T cells targeting HER2 and IL13Rα2 mitigate tumor antigen escape.

    PubMed

    Hegde, Meenakshi; Mukherjee, Malini; Grada, Zakaria; Pignata, Antonella; Landi, Daniel; Navai, Shoba A; Wakefield, Amanda; Fousek, Kristen; Bielamowicz, Kevin; Chow, Kevin K H; Brawley, Vita S; Byrd, Tiara T; Krebs, Simone; Gottschalk, Stephen; Wels, Winfried S; Baker, Matthew L; Dotti, Gianpietro; Mamonkin, Maksim; Brenner, Malcolm K; Orange, Jordan S; Ahmed, Nabil

    2016-08-01

    In preclinical models of glioblastoma, antigen escape variants can lead to tumor recurrence after treatment with CAR T cells that are redirected to single tumor antigens. Given the heterogeneous expression of antigens on glioblastomas, we hypothesized that a bispecific CAR molecule would mitigate antigen escape and improve the antitumor activity of T cells. Here, we created a CAR that joins a HER2-binding scFv and an IL13Rα2-binding IL-13 mutein to make a tandem CAR exodomain (TanCAR) and a CD28.ζ endodomain. We determined that patient TanCAR T cells showed distinct binding to HER2 or IL13Rα2 and had the capability to lyse autologous glioblastoma. TanCAR T cells exhibited activation dynamics that were comparable to those of single CAR T cells upon encounter of HER2 or IL13Rα2. We observed that TanCARs engaged HER2 and IL13Rα2 simultaneously by inducing HER2-IL13Rα2 heterodimers, which promoted superadditive T cell activation when both antigens were encountered concurrently. TanCAR T cell activity was more sustained but not more exhaustible than that of T cells that coexpressed a HER2 CAR and an IL13Rα2 CAR, T cells with a unispecific CAR, or a pooled product. In a murine glioblastoma model, TanCAR T cells mitigated antigen escape, displayed enhanced antitumor efficacy, and improved animal survival. Thus, TanCAR T cells show therapeutic potential to improve glioblastoma control by coengaging HER2 and IL13Rα2 in an augmented, bivalent immune synapse that enhances T cell functionality and reduces antigen escape.

  9. Tandem CAR T cells targeting HER2 and IL13Rα2 mitigate tumor antigen escape

    PubMed Central

    Mukherjee, Malini; Grada, Zakaria; Pignata, Antonella; Landi, Daniel; Navai, Shoba A.; Wakefield, Amanda; Bielamowicz, Kevin; Chow, Kevin K.H.; Brawley, Vita S.; Byrd, Tiara T.; Krebs, Simone; Gottschalk, Stephen; Wels, Winfried S.; Baker, Matthew L.; Dotti, Gianpietro; Mamonkin, Maksim; Brenner, Malcolm K.

    2016-01-01

    In preclinical models of glioblastoma, antigen escape variants can lead to tumor recurrence after treatment with CAR T cells that are redirected to single tumor antigens. Given the heterogeneous expression of antigens on glioblastomas, we hypothesized that a bispecific CAR molecule would mitigate antigen escape and improve the antitumor activity of T cells. Here, we created a CAR that joins a HER2-binding scFv and an IL13Rα2-binding IL-13 mutein to make a tandem CAR exodomain (TanCAR) and a CD28.ζ endodomain. We determined that patient TanCAR T cells showed distinct binding to HER2 or IL13Rα2 and had the capability to lyse autologous glioblastoma. TanCAR T cells exhibited activation dynamics that were comparable to those of single CAR T cells upon encounter of HER2 or IL13Rα2. We observed that TanCARs engaged HER2 and IL13Rα2 simultaneously by inducing HER2-IL13Rα2 heterodimers, which promoted superadditive T cell activation when both antigens were encountered concurrently. TanCAR T cell activity was more sustained but not more exhaustible than that of T cells that coexpressed a HER2 CAR and an IL13Rα2 CAR, T cells with a unispecific CAR, or a pooled product. In a murine glioblastoma model, TanCAR T cells mitigated antigen escape, displayed enhanced antitumor efficacy, and improved animal survival. Thus, TanCAR T cells show therapeutic potential to improve glioblastoma control by coengaging HER2 and IL13Rα2 in an augmented, bivalent immune synapse that enhances T cell functionality and reduces antigen escape. PMID:27427982

  10. Antigen-specific CD4{sup +} effector T cells: Analysis of factors regulating clonal expansion and cytokine production

    SciTech Connect

    Ohnuki, Kazunobu; Watanabe, Yuri; Takahashi, Yusuke; Kobayashi, Sakiko; Watanabe, Shiho; Ogawa, Shuhei; Kotani, Motoko; Kozono, Haruo; Tanabe, Kazunari; Abe, Ryo

    2009-03-20

    In order to fully understand T cell-mediated immunity, the mechanisms that regulate clonal expansion and cytokine production by CD4{sup +} antigen-specific effector T cells in response to a wide range of antigenic stimulation needs clarification. For this purpose, panels of antigen-specific CD4{sup +} T cell clones with different thresholds for antigen-induced proliferation were generated by repeated stimulation with high- or low-dose antigen. Differences in antigen sensitivities did not correlate with expression of TCR, CD4, adhesion or costimulatory molecules. There was no significant difference in antigen-dependent cytokine production by TG40 cells transfected with TCR obtained from either high- or low-dose-responding T cell clones, suggesting that the affinity of TCRs for their ligands is not primary determinant of T cell antigen reactivity. The proliferative responses of all T cell clones to both peptide stimulation and to TCR{beta} crosslinking revealed parallel dose-response curves. These results suggest that the TCR signal strength of effector T cells and threshold of antigen reactivity is determined by an intrinsic property, such as the TCR signalosome and/or intracellular signaling machinery. Finally, the antigen responses of high- and low-peptide-responding T cell clones reveal that clonal expansion and cytokine production of effector T cells occur independently of antigen concentration. Based on these results, the mechanisms underlying selection of high 'avidity' effector and memory T cells in response to pathogen are discussed.

  11. Hodgkin and sternberg-reed cell antigen(s) detected by an antiserum to a cell line (L428) derived from Hodgkin's disease.

    PubMed

    Stein, H; Gerdes, J; Kirchner, H; Schaadt, M; Diehl, V

    1981-10-15

    Antisera to the cell line L428, derived from Hodgkin's disease, were raised in rabbits by injecting L428 cells intravenously and subcutaneously. The anti-L428 cell serum that did not react with HLA-DR was absorbed with tonsil cell plus acute myeloid leukemia cells or tonsil cells plus neutrophils, monocytes, and blood lymphocytes. Then it was tested for its ability to discriminate between L428 cells, Hodgkin and Sternberg-Reed cells, and various other cells. It was found that the anti L428 cell serum absorbed with tonsil cells plus acute myeloid leukemia cells stained only L428 cells, Hodgkin and Sternberg-Reed cells, and neutrophils. The anti L428 cell serum absorbed with tonsil cell plus neutrophils, monocytes, and blood lymphocytes reacted with L428 cells and Hodgkin and sternberg-Reed cells from 13 cases of Hodgkin's disease. It did not react with any other cell type present in the blood or in lymphoid tissue or with cells from five cases of non-Hodgkin's lymphoma. The absorbed anti-L428 cell serum also failed to stain Daudi and HRIK cell line cells. We conclude that the anti-L428 cell serum defines an antigen that is apparently restricted in expression to L428 cells and Hodgkin and Sternberg-Reed cells. This is a strong indication that the L428 cell line cells are derived from Hodgkin and Sternberg-Reed cells.

  12. Antigens protected functional red blood cells by the membrane grafting of compact hyperbranched polyglycerols.

    PubMed

    Chapanian, Rafi; Constantinescu, Iren; Brooks, Donald E; Scott, Mark D; Kizhakkedathu, Jayachandran

    2013-01-02

    Red blood cell (RBC) transfusion is vital for the treatment of a number of acute and chronic medical problems such as thalassemia major and sickle cell anemia. Due to the presence of multitude of antigens on the RBC surface (~308 known antigens), patients in the chronic blood transfusion therapy develop alloantibodies due to the miss match of minor antigens on transfused RBCs. Grafting of hydrophilic polymers such as polyethylene glycol (PEG) and hyperbranched polyglycerol (HPG) forms an exclusion layer on RBC membrane that prevents the interaction of antibodies with surface antigens without affecting the passage of small molecules such as oxygen, glucose, and ions. At present no method is available for the generation of universal red blood donor cells in part because of the daunting challenge presented by the presence of large number of antigens (protein and carbohydrate based) on the RBC surface and the development of such methods will significantly improve transfusion safety, and dramatically improve the availability and use of RBCs. In this report, the experiments that are used to develop antigen protected functional RBCs by the membrane grafting of HPG and their characterization are presented. HPGs are highly biocompatible compact polymers, and are expected to be located within the cell glycocalyx that surrounds the lipid membrane and mask RBC surface antigens.

  13. The Molecular Determinants of Antibody Recognition and Antigenic Drift in the H3 Hemagglutinin of Swine Influenza A Virus

    PubMed Central

    Abente, Eugenio J.; Santos, Jefferson; Lewis, Nicola S.; Gauger, Phillip C.; Stratton, Jered; Skepner, Eugene; Rajao, Daniela S.

    2016-01-01

    ABSTRACT Influenza A virus (IAV) of the H3 subtype is an important respiratory pathogen that affects both humans and swine. Vaccination to induce neutralizing antibodies against the surface glycoprotein hemagglutinin (HA) is the primary method used to control disease. However, due to antigenic drift, vaccine strains must be periodically updated. Six of the 7 positions previously identified in human seasonal H3 (positions 145, 155, 156, 158, 159, 189, and 193) were also indicated in swine H3 antigenic evolution. To experimentally test the effect on virus antigenicity of these 7 positions, substitutions were introduced into the HA of an isogenic swine lineage virus. We tested the antigenic effect of these introduced substitutions by using hemagglutination inhibition (HI) data with monovalent swine antisera and antigenic cartography to evaluate the antigenic phenotype of the mutant viruses. Combinations of substitutions within the antigenic motif caused significant changes in antigenicity. One virus mutant that varied at only two positions relative to the wild type had a >4-fold reduction in HI titers compared to homologous antisera. Potential changes in pathogenesis and transmission of the double mutant were evaluated in pigs. Although the double mutant had virus shedding titers and transmissibility comparable to those of the wild type, it caused a significantly lower percentage of lung lesions. Elucidating the antigenic effects of specific amino acid substitutions at these sites in swine H3 IAV has important implications for understanding IAV evolution within pigs as well as for improved vaccine development and control strategies in swine. IMPORTANCE A key component of influenza virus evolution is antigenic drift mediated by the accumulation of amino acid substitutions in the hemagglutinin (HA) protein, resulting in escape from prior immunity generated by natural infection or vaccination. Understanding which amino acid positions of the HA contribute to the ability

  14. Granuloma cells in chronic inflammation express CD205 (DEC205) antigen and harbor proliferating T lymphocytes: similarity to antigen-presenting cells.

    PubMed

    Ohtani, Haruo

    2013-02-01

    Granulomas are classified as immune or foreign body granulomas. Of these, the immune granulomas, a hallmark of granulomatous inflammation, are closely related to cell-mediated immune responses. The aim of the present study is to characterize immune granuloma cells in 33 patients with granulomatous inflammation focusing on the expression of CD205 (DEC205), a cell surface marker of antigen presenting cells, and their spatial relationship to T cells. CD205 was frequently expressed by immune granuloma cells, in contrast to foreign body granuloma cells that lacked CD205 expression. T cells were not only distributed in a lymphocyte collar around the granuloma, but also present among the granuloma cells (termed 'intra-granuloma T cells'). Intra-granuloma T cells stained positive for Ki-67 (median positivity = 9.4%) by double immunostaining for CD3 and Ki-67. This indicated the presence of proliferative stimuli within the granuloma that could activate the intra-granuloma T cells. The labeling index of Ki-67 in intra-granuloma T cells was significantly higher than that of T cells in the lymphocyte collar (P < 0.0001) or T cells in the T cell zone (paracortex) of chronic tonsillitis or reactive lymphadenitis (P = 0.002). These data indicate a close similarity between immune granulomas and antigen presenting cells.

  15. Antigenic differences between AKR lymphoma and thymus cells leading to detection of a tumor antigen associated with immunological enhancement.

    PubMed

    Laguens, R P; Colmerauer, M E; Segal, A; Pasqualini, C D

    1978-06-15

    In an experimental model conditioning for enhancement, an AKR lymphoma was made to grow in BALB/c mice, permitting the simultaneous comparison of tumor-bearing (progressor) and tumor-rejecting (regressor) animals. By immunofluorescence using as target AKR lymphoma and normal thymus cells, both acetone-fixed and unfixed, it was observed that the allogeneic progressor serum contained three antibodies, two of which could be asborbed by thymocytes while the other combined selectively with the acetone-fixed lymphoma target. This tumor-specific antibody could not be detected in regressor serum which, on the other hand, could be completely absorbed by thymocytes. The identification of this acetone-resistant tumor antigen led to the preparation of aceton-treated acellular lymphoma extracts: a precipitate was obtained which upon inoculation in BALB/c mice produced an antiserum that combined selectively with lymphoma targets. In vivo experiments showed that pretreatment with this antigen led to a significant increase in allogeneic tumor incidence, 76% as compared to 37% in the controls. It is concluded that in this allogeneic model, an acetone-resistant tumor-specific antigen and the corresponding antibody are involved in tumor enhancement.

  16. Dendritic Cell Targeting of Bacillus anthracis Protective Antigen Expressed by Lactobacillus acidophilus Protects Mice from Lethal Challenge

    DTIC Science & Technology

    2008-10-28

    Dendritic cell targeting of Bacillus anthracis protective antigen expressed by Lactobacillus acidophilus protects mice from lethal challenge M...lethal chal- lenge. A vaccine strategy was established by using Lactobacillus acidophilus to deliver Bacillus anthracis protective antigen (PA) via...4. TITLE AND SUBTITLE Dendritic cell targeting of Bacillus anthracis protective antigen expressed by Lactobacillus acidophilus protects mice

  17. Effect of antigen/antibody ratio on macrophage uptake, processing, and presentation to T cells of antigen complexed with polyclonal antibodies

    PubMed Central

    1991-01-01

    Activation of a galactosidase-specific murine T hybridoma clone and of a human tetanus toxoid-specific T clone by antigen-presenting cells (APC) was used to evaluate the regulatory function of antibodies complexed with the relevant antigen. Complexed antigen, in fact, is taken up with high efficiency thanks to Fc receptors borne by APC. Antibody/antigen ratio in the complexes proved to be a critical parameter in enhancing antigen presentation. Complexes in moderate antibody excess provided optimal T cell activation independently of the physical state of the complexes (precipitated by a second antibody or solubilized by complement). Complexes in extreme antibody excess, on the contrary, did not yield T cell activation although taken up by APC efficiently. The effect of antibodies at extreme excess was observed with substimulatory dose of antigen (loss of potentiation) and with optimal dose of antigen (loss of stimulation). An excess of specific polyclonal antibodies hampers proteolytic degradation of antigen in vitro, supporting the view that a similar mechanism may operate within the APC that have internalized immune complexes in extreme antibody excess. The possibility that immune complex forming in extreme antibody excess may turn off the T cell response is proposed as a regulatory mechanism. PMID:1985125

  18. How Antigen Quantity and Quality Determine T-Cell Decisions in Lymphoid Tissue▿ †

    PubMed Central

    Zheng, Huan; Jin, Bo; Henrickson, Sarah E.; Perelson, Alan S.; von Andrian, Ulrich H.; Chakraborty, Arup K.

    2008-01-01

    T lymphocytes (T cells) express T-cell receptor (TCR) molecules on their surface that can recognize peptides (p) derived from antigenic proteins bound to products of the major histocompatibility complex (MHC) genes. The pMHC molecules are expressed on the surface of antigen-presenting cells, such as dendritic cells (DCs). T cells first encounter antigen on DCs in lymph nodes (LN). Intravital microscopy experiments show that upon entering the LN containing antigen, CD8+ T cells first move rapidly. After a few hours, they stop and make extended contacts with DCs. The factors that determine when and how this transition occurs are not well understood. We report results from computer simulations that suggest that the duration of phase one is related to the low probability of productive interactions between T cells and DCs. This is demonstrated by our finding that the antigen dose and type determine when such a transition occurs. These results are in agreement with experimental observations. TCR-pMHC binding characteristics and the antigen dose determine the time required for a productive T-cell-DC encounter (resulting in sustained contact). We find that the ratio of this time scale and the half-life of the pMHC complex itself provide a consolidated measure of antigen quantity and type. Results obtained upon varying different measures of antigen quantity and type fall on one curve when graphed against this ratio of time scales. Thus, we provide a mechanism for how the effects of varying one set of parameters are influenced by other prevailing conditions. This understanding should help guide future experimentation. PMID:18426917

  19. Innate Immune Pattern Recognition: A Cell Biological Perspective

    PubMed Central

    Brubaker, Sky W.; Bonham, Kevin S.; Zanoni, Ivan

    2016-01-01

    Receptors of the innate immune system detect conserved determinants of microbial and viral origin. Activation of these receptors initiates signaling events that culminate in an effective immune response. Recently, the view that innate immune signaling events rely on and operate within a complex cellular infrastructure has become an important framework for understanding the regulation of innate immunity. Compartmentalization within this infrastructure provides the cell with the ability to assign spatial information to microbial detection and regulate immune responses. Several cell biological processes play a role in the regulation of innate signaling responses; at the same time, innate signaling can engage cellular processes as a form of defense or to promote immunological memory. In this review, we highlight these aspects of cell biology in pattern-recognition receptor signaling by focusing on signals that originate from the cell surface, from endosomal compartments, and from within the cytosol. PMID:25581309

  20. Identification and visualization of multidimensional antigen-specific T-cell populations in polychromatic cytometry data.

    PubMed

    Lin, Lin; Frelinger, Jacob; Jiang, Wenxin; Finak, Greg; Seshadri, Chetan; Bart, Pierre-Alexandre; Pantaleo, Giuseppe; McElrath, Julie; DeRosa, Steve; Gottardo, Raphael

    2015-07-01

    An important aspect of immune monitoring for vaccine development, clinical trials, and research is the detection, measurement, and comparison of antigen-specific T-cells from subject samples under different conditions. Antigen-specific T-cells compose a very small fraction of total T-cells. Developments in cytometry technology over the past five years have enabled the measurement of single-cells in a multivariate and high-throughput manner. This growth in both dimensionality and quantity of data continues to pose a challenge for effective identification and visualization of rare cell subsets, such as antigen-specific T-cells. Dimension reduction and feature extraction play pivotal role in both identifying and visualizing cell populations of interest in large, multi-dimensional cytometry datasets. However, the automated identification and visualization of rare, high-dimensional cell subsets remains challenging. Here we demonstrate how a systematic and integrated approach combining targeted feature extraction with dimension reduction can be used to identify and visualize biological differences in rare, antigen-specific cell populations. By using OpenCyto to perform semi-automated gating and features extraction of flow cytometry data, followed by dimensionality reduction with t-SNE we are able to identify polyfunctional subpopulations of antigen-specific T-cells and visualize treatment-specific differences between them.

  1. Aberrant Cosmc genes result in Tn antigen expression in human colorectal carcinoma cell line HT-29

    PubMed Central

    Yu, Xiaofeng; Du, Zhenzhen; Sun, Xuhong; Shi, Chuanqin; Zhang, Huaixiang; Hu, Tao

    2015-01-01

    The Tn antigen, which arises from mutation in the Cosmc gene is one of the most common tumor associated carbohydrate antigens. Cosmc resides in X24 encoded by a single gene and functions as a specific molecular chaperone for T-synthase. While the Tn antigen cannot be detected in normal cells, Cosmc mutations inactivate T-synthase and consequently result in Tn antigen expression within certain cancers. In addition to this Cosmc mutation-induced expression, the Tn antigen is also expressed in such cell lines as Jurkat T, LSC and LS174T. Whether the Cosmc mutation is present in the colon cancer cell line HT-29 is still unclear. Here, we isolate HT-29-Tn+ cells from HT-29 cells derived from a female colon cancer patient. These HT-29-Tn+ cells show a loss of the Cosmc gene coding sequence (CDS) leading to an absence of T-synthase activity and Tn antigen expression. Additionally, almost no methylation of Cosmc CpG islands was detected in HT-29-Tn+ as well as in HT-29-Tn- and Tn- tumor cells from male patients. In contrast, the methylation frequency of CpG island of Cosmc in normal female cells was ~50%. Only one active allele of Cosmc existed in HT-29-Tn+ and HT-29-Tn- cells as based upon detection of SNP sites. These results indicate that Tn antigens expression and T-synthase inactivity in HT-29-Tn+ cells can be related to the absence of CDS in Cosmc active alleles, while an inactive allele deletion of Cosmc in HT-29 cells has no influence on Cosmc function. PMID:26045765

  2. Signal transduction-associated and cell activation-linked antigens expressed in human mast cells.

    PubMed

    Valent, Peter; Ghannadan, Minoo; Hauswirth, Alexander W; Schernthaner, Gerit-Holger; Sperr, Wolfgang R; Arock, Michel

    2002-05-01

    Mast cells (MCs) are multifunctional hematopoietic effector cells that produce and release an array of biologically active mediator substances. Growth and functions of MCs are regulated by cytokines, other extracellular factors, surface and cytoplasmic receptors, oncogene products, and a complex network of signal transduction cascades. Key regulators of differentiation of MCs appear to be stem cell factor (SCF) and its tyrosine kinase receptor KIT (c-kit proto-oncogene product=CD117), downstream-acting elements, and the mi transcription factor (MITF). Signaling through KIT is negatively regulated by the signal regulatory protein (SIRP)-alpha (CD172a)-SHP-1-pathway that is disrupted in neoplastic MCs in MC proliferative disorders. Both KIT and FcepsilonRI are involved in MC activation and mediator release. Activation of MCs through FcepsilonRI is associated with increased expression of activation-linked membrane antigens as well as with signaling events involving Lyn and Syk kinases, the phosphatidylinositol-3-kinase-pathway, Ras pathway, and the phospholipase C-protein kinase C pathway. A similar network of signaling is found in SCF-activated MCs. The current article gives an overview on signal transduction-associated and activation-linked antigens expressed in human MCs. Wherever possible the functional implication of signaling pathways and antigen expression are discussed.

  3. Common Ewing sarcoma-associated antigens fail to induce natural T cell responses in both patients and healthy individuals.

    PubMed

    Altvater, Bianca; Kailayangiri, Sareetha; Theimann, Nadine; Ahlmann, Martina; Farwick, Nicole; Chen, Christiane; Pscherer, Sibylle; Neumann, Ilka; Mrachatz, Gabriele; Hansmeier, Anna; Hardes, Jendrik; Gosheger, Georg; Juergens, Heribert; Rossig, Claudia

    2014-10-01

    Disseminated or relapsed Ewing sarcoma (EwS) has remained fatal in the majority of patients. A promising approach to preventing relapse after conventional therapy is to establish tumor antigen-specific immune control. Efficient and specific T cell memory against the tumor depends on the expansion of rare T cells with native specificity against target antigens overexpressed by the tumor. Candidate antigens in EwS include six-transmembrane epithelial antigen of the prostate-1 (STEAP1), and the human cancer/testis antigens X-antigen family member 1 (XAGE1) and preferentially expressed antigen in melanoma (PRAME). Here, we screened normal donors and EwS patients for the presence of circulating T cells reactive with overlapping peptide libraries of these antigens by IFN-γ Elispot analysis. The majority of 22 healthy donors lacked detectable memory T cell responses against STEAP1, XAGE1 and PRAME. Moreover, ex vivo detection of T cells specific for these antigens in both blood and bone marrow were limited to a minority of EwS patients and required nonspecific T cell prestimulation. Cytotoxic T cells specific for the tumor-associated antigens were efficiently and reliably generated by in vitro priming using professional antigen-presenting cells and optimized cytokine stimulation; however, these T cells failed to interact with native antigen processed by target cells and with EwS cells expressing the antigen. We conclude that EwS-associated antigens fail to induce efficient T cell receptor (TCR)-mediated antitumor immune responses even under optimized conditions. Strategies based on TCR engineering could provide a more effective means to manipulating T cell immunity toward targeted elimination of tumor cells.

  4. Cell-mediated immunity to hepatitis B virus antigens in mice: correlation of in vivo and in vitro assays.

    PubMed Central

    De Moerloose, P A; Frazer, I H; Sewell, W A; Collins, E J; Mackay, I R

    1986-01-01

    Cell mediated immunity (CMI) to hepatitis B viral antigens was studied in BALB/mice after immunization with purified hepatitis B surface antigen (HBsAg), or core antigen (HBcAg), with adjuvants. The two in vitro assays for cell-mediated immunity (CMI), utilizing lymph node cells, were release of interferon after exposure to antigen, and blast transformation of lymphocytes, and the in vivo assay was ear swelling at 24 h after local injection of antigen. Immunization with HBsAg or HBcAg with adjuvants induced antigen-specific cutaneous reactivity; if no adjuvants were given, immunization with HBcAg, but not HBsAg, induced cutaneous reactivity. CMI could be adoptively transferred by lymph node cells, but for only a limited period after immunization with HbsAg or HBcAg. The ability of lymph node cells from mice immunized with HBV antigens to transfer adoptively CMI correlated well with their production of interferon after challenge with antigen in vitro, but less well with blastogenesis after challenge with antigen in vitro, or with cutaneous reactivity to antigen in the donor mouse. Reliable antigen-specific lymphokine release assays, rather than blast transformation of lymphocytes or cutaneous reactivity after antigen challenge, are required to assess CMI to HBV antigens in the mouse and, by inference, in man. Images Fig. 1 PMID:3091300

  5. Antigen-specific regulation of IgE antibodies by non-antigen-specific γδ T cells1

    PubMed Central

    Huang, Yafei; Aydintug, M. Kemal; Loomis, Joshua; MacLeod, Megan K.; McKee, Amy S.; Kirchenbaum, Greg; Jakubzick, Claudia V.; Kedl, Ross M.; Sun, Deming; Jacobelli, Jordan; O'Brien, Rebecca L.; Born, Willi K.

    2013-01-01

    We re-examined the observation that γδ T cells, when transferred from mice tolerized to an inhaled conventional antigen (Ag), suppress the allergic IgE response to this Ag specifically. Using ovalbumin and hen egg lysozyme in crisscross fashion, we confirmed the Ag-specific IgE regulatory effect of the γδ T cells. Although only Vγ4+ γδ T cells are regulators, the Ag specificity does not stem from specificity of their γδ TCRs. Instead, the Vγ4+ γδ T cells failed to respond to either Ag, but rapidly acquired Ag-specific regulatory function in vivo following i.v. injection of non-T cells derived from the spleen of Ag-tolerized mice. This correlated with their in vivo Ag acquisition from i.v. injected Ag-loaded splenic non-T cells, and in vivo transfer of membrane label provided evidence for direct contact between the injected splenic non-T cells and the Vγ4+ γδ T cells. Together, our data suggest that Ag itself, when acquired by γδ T cells, directs the specificity of their IgE suppression. PMID:23275606

  6. Discovery of chemotherapy-associated ovarian cancer antigens by interrogating memory T cells.

    PubMed

    Paroli, Marino; Bellati, Filippo; Videtta, Melissa; Focaccetti, Chiara; Mancone, Carmine; Donato, Tiziana; Antonilli, Morena; Perniola, Giorgia; Accapezzato, Daniele; Napoletano, Chiara; Nuti, Marianna; Bartolazzi, Armando; Panici, Pierluigi Benedetti; Tripodi, Marco; Palombo, Fabio; Barnaba, Vincenzo

    2014-04-15

    According to the immunogenic cell death hypothesis, clinical chemotherapy treatments may result in CD8(+) and CD4(+) T-cell responses against tumor cells. To discover chemotherapy-associated antigens (CAAs), T cells derived from ovarian cancer (OC) patients (who had been treated with appropriate chemotherapy protocols) were interrogated with proteins isolated from primary OC cells. We screened for immunogenicity using two-dimensional electrophoresis gel-eluted OC proteins. Only the selected immunogenic antigens were molecularly characterized by mass-spectrometry-based analysis. Memory T cells that recognized antigens associated with apoptotic (but not live) OC cells were correlated with prolonged survival in response to chemotherapy, supporting the model of chemotherapy-induced apoptosis as an adjuvant of anti-tumor immunity. The strength of both memory CD4(+) and CD8(+) T cells producing either IFN-γ or IL-17 in response to apoptotic OC antigens was also significantly greater in Responders to chemotherapy than in nonresponders. Immunogenicity of some of these antigens was confirmed using recombinant proteins in an independent set of patients. The T-cell interrogation system represents a strategy of reverse tumor immunology that proposes to identify CAAs, which may then be validated as possible prognostic tumor biomarkers or cancer vaccines.

  7. Killer artificial antigen-presenting cells: the synthetic embodiment of a 'guided missile'.

    PubMed

    Schütz, Christian; Oelke, Mathias; Schneck, Jonathan P; Mackensen, Andreas; Fleck, Martin

    2010-07-01

    At present, the treatment of T-cell-dependent autoimmune diseases relies exclusively on strategies leading to nonspecific suppression of the immune systems causing a substantial reduced ability to control concomitant infections or malignancies. Furthermore, long-term treatment with most drugs is accompanied by several serious adverse effects and does not consequently result in cure of the primary immunological malfunction. By contrast, antigen-specific immunotherapy offers the potential to achieve the highest therapeutic efficiency in accordance with minimal adverse effects. Therefore, several studies have been performed utilizing antigen-presenting cells specifically engineered to deplete allo- or antigen-specific T cells ('guided missiles'). Many of these strategies take advantage of the Fas/Fas ligand signaling pathway to efficiently induce antigen-presenting cell-mediated apoptosis in targeted T cells. In this article, we discuss the advantages and shortcomings of a novel non-cell-based 'killer artificial antigen-presenting cell' strategy, developed to overcome obstacles related to current cell-based approaches for the treatment of T-cell-mediated autoimmunity.

  8. Dissecting the Tumor Myeloid Compartment Reveals Rare Activating Antigen Presenting Cells, Critical for T cell Immunity

    PubMed Central

    Broz, Miranda; Binnewies, Mikhail; Boldajipour, Bijan; Nelson, Amanda; Pollock, Joshua; Erle, David; Barczak, Andrea; Rosenblum, Michael; Daud, Adil; Barber, Diane; Amigorena, Sebastian; van’t Veer, Laura J.; Sperling, Anne; Wolf, Denise; Krummel, Matthew F.

    2014-01-01

    SUMMARY It is well understood that antigen-presenting cells (APC) within tumors typically do not maintain cytotoxic T cell (CTL) function, despite engaging them. Across multiple mouse tumor models and human tumor biopsies, we have delineated the intratumoral dendritic-cell (DC) populations as distinct from macrophage populations. Within these, CD103+ DCs are extremely sparse and yet remarkably capable CTL stimulators. These are uniquely dependent upon IRF8, Zbtb46 and Batf3 transcription factors and generated by GM-CSF and Flt3L cytokines. Regressing tumors have higher proportions of these cells, T-cell dependent immune clearance relies upon them, and abundance of their transcripts in human tumors correlates with clinical outcome. This cell type presents opportunities for prognostic and therapeutic approaches across multiple cancer types. PMID:25446897

  9. Successive Administration of Streptococcus Type 5 Group A Antigens and S. typhimurium Antigenic Complex Corrects Elevation of Serum Cytokine Concentration and Number of Bone Marrow Stromal Pluripotent Cells in CBA Mice Induced by Each Antigen Separately.

    PubMed

    Gorskaya, Yu F; Danilova, T A; Grabko, V I; Nesterenko, V G

    2015-12-01

    Administration of bacterial antigens to CBA mice induced an increase in serum concentration of virtually all cytokines with a peak in 4 h after administration of S. typhimurium antigens and in 7 h after administration of streptococcus antigens. In 20 h, cytokine concentrations returned to the control level or were slightly below it. In 4 h after administration of S. typhimurium antigens preceded 3 h before by administration of streptococcus antigens, we observed a significant decrease in serum concentrations of IFN-γ, IL-10, GM-CSF, IL-12, and TNF-α, in comparison with injection S. typhimurium antigens alone and IL-5, IL-10, GM-CSF, and TNF-α in comparison with injection of streptococcus antigens alone; the concentrations of IL-2 and IFN-γ, in contrast, increased by 1.5 times in this case. In 20 h after administration of S. typhimurium antigens, the number of multipotential stromal cells (MSC) in the bone marrow and their cloning efficiency (ECF-MSC) increased by 4.8 and 4.4 times, respectively, in comparison with the control, while after administration of streptococcus antigens by 2.6 and 2.4 times, respectively. In 20 h after administration of S. typhimurium antigens preceded 3 h before by administration of streptococcus antigens, these parameters increased by 3.2 and 2.9 times, respectively, in comparison with the control, i.e. the observed increase in the level of MSC count and ECF-MSC is more consistent with the response of the stromal tissue to streptococcus antigens. Thus, successive administration of two bacterial antigens corrected both serum cytokine profiles and MSC response to administration of each antigen separately, which indicates changeability of the stromal tissue in response to changes in the immune response.

  10. Antigen-induced regulatory T cells in HBV chronically infected patients.

    PubMed

    Barboza, Luisa; Salmen, Siham; Goncalves, Loredana; Colmenares, Melisa; Peterson, Darrell; Montes, Henry; Cartagirone, Raimondo; Gutiérrez, Maria del Carmen; Berrueta, Lisbeth

    2007-11-10

    T cell response against HBV is vigorous in patients with acute hepatitis who clear the virus, whereas it is weak and narrowly focused in patients with chronic disease. We report that following incubation with HBcAg, a population of CD4+FoxP3+ cells expressing phenotypic markers of both natural and induced Tregs, can be antigen-induced from peripheral mononuclear cells. Conversely, naive and naturally immune subjects did not increase CD4+FoxP3+ Tregs following stimulation with HBcAg, supporting the idea that natural Tregs are able to respond specifically to HBV antigen. Furthermore, increased frequencies of antigen-induced CD4+FoxP3+IL-10+ Tregs correlated with viral load, suggesting that antigen-induced Tregs could contribute to an inadequate response against the virus, leading to chronic infection and support the view that specific natural Tregs may be implicated in host immune tolerance during HBV infection.

  11. Purification and identification of cell surface antigens using lamprey monoclonal antibodies

    PubMed Central

    Yu, Cuiling; Ali, Shabab; St. Germain, Jonathan; Liu, Yanling; Yu, Xuecong; Jaye, David L.; Moran, Michael F.; Cooper, Max D.; Ehrhardt, Götz R.A.

    2013-01-01

    Variable lymphocyte receptor (VLR) B antibodies of the evolutionary distant sea lamprey are structurally distinct from conventional mammalian antibodies. The different protein architecture and large evolutionary distance of jawless vertebrates suggest that VLR antibodies may represent promising tools for biomarker discovery. Here we report the generation of panels of monoclonal VLR antibodies from lamprey larvae immunized with human T cells and the use of a recombinant monoclonal VLR antibody for antigen purification and mass spectrometric identification. We demonstrate that despite predicted low affinity of individual VLR antigen binding units to the antigen, the high avidity resulting from decameric assembly of secreted VLR antibodies allows for efficient antigen capture and subsequent identification by mass spectometry. We show that VLR antibodies detect their antigens with high specificity and can be used in various standard laboratory application techniques. The lamprey antibodies are novel reagents that can complement conventional monoclonal antibodies in multiple scientific research disciplines. PMID:22964555

  12. Immunogenicity of recombinant Mycobacterium bovis bacille Calmette-Guèrin clones expressing T and B cell epitopes of Mycobacterium tuberculosis antigens.

    PubMed

    Mohamud, Rohimah; Azlan, Maryam; Yero, Daniel; Alvarez, Nadine; Sarmiento, Maria E; Acosta, Armando; Norazmi, Mohd-Nor

    2013-01-01

    Recombinant Mycobacterium bovis bacille Calmette-Guèrin (rBCG) expressing three T cell epitopes of Mycobacterium tuberculosis (MTB) Ag85B antigen (P1, P2, P3) fused to the Mtb8.4 protein (rBCG018) or a combination of these antigens fused to B cell epitopes from ESAT-6, CFP-10 and MTP40 proteins (rBCG032) were used to immunize Balb/c mice. Total IgG responses were determined against Mtb8.4 antigen and ESAT-6 and CFP-10 B cell epitopes after immunization with rBCG032. Mice immunized with rBCG032 showed a significant increase in IgG1 and IgG2a antibodies against ESAT-6 and MTP40 (P1) B cell epitopes and IgG3 against both P1 and P2 B cell epitopes of MPT40. Splenocytes from mice immunized with rBCG018 proliferated against Ag85B P2 and P3 T cell epitopes and Mtb8.4 protein whereas those from mice-immunized with rBCG032 responded against all Ag85B epitopes and the ESAT-6 B cell epitope. CD4⁺ and CD8⁺ lymphocytes from mice immunized with rBCG018 produced primarily Th1 type cytokines in response to the T cell epitopes. Similar pattern of recognition against the T cell epitopes were obtained with rBCG032 with the additional recognition of ESAT-6, CFP-10 and one of the MTP40 B cell epitopes with the same pattern of cytokines. This study demonstrates that rBCG constructs expressing either T or T and B cell epitopes of MTB induced appropriate immunogenicity against MTB.

  13. Comprehensive red blood cell and platelet antigen prediction from whole genome sequencing: proof of principle

    PubMed Central

    Westhoff, Connie M.; Uy, Jon Michael; Aguad, Maria; Smeland‐Wagman, Robin; Kaufman, Richard M.; Rehm, Heidi L.; Green, Robert C.; Silberstein, Leslie E.

    2015-01-01

    BACKGROUND There are 346 serologically defined red blood cell (RBC) antigens and 33 serologically defined platelet (PLT) antigens, most of which have known genetic changes in 45 RBC or six PLT genes that correlate with antigen expression. Polymorphic sites associated with antigen expression in the primary literature and reference databases are annotated according to nucleotide positions in cDNA. This makes antigen prediction from next‐generation sequencing data challenging, since it uses genomic coordinates. STUDY DESIGN AND METHODS The conventional cDNA reference sequences for all known RBC and PLT genes that correlate with antigen expression were aligned to the human reference genome. The alignments allowed conversion of conventional cDNA nucleotide positions to the corresponding genomic coordinates. RBC and PLT antigen prediction was then performed using the human reference genome and whole genome sequencing (WGS) data with serologic confirmation. RESULTS Some major differences and alignment issues were found when attempting to convert the conventional cDNA to human reference genome sequences for the following genes: ABO, A4GALT, RHD, RHCE, FUT3, ACKR1 (previously DARC), ACHE, FUT2, CR1, GCNT2, and RHAG. However, it was possible to create usable alignments, which facilitated the prediction of all RBC and PLT antigens with a known molecular basis from WGS data. Traditional serologic typing for 18 RBC antigens were in agreement with the WGS‐based antigen predictions, providing proof of principle for this approach. CONCLUSION Detailed mapping of conventional cDNA annotated RBC and PLT alleles can enable accurate prediction of RBC and PLT antigens from whole genomic sequencing data. PMID:26634332

  14. The generation and antigen-specificity of CD4+CD25+ regulatory T cells.

    PubMed

    Taams, Leonie S; Curnow, S John; Vukmanovic-Stejic, M; Akbar, Arne N

    2006-09-01

    CD4+CD25+ regulatory T cells are essential components of the immune system. They help to maintain immune tolerance by exerting suppressive effects on cells of the adaptive and innate immune system. In the last few years there has been an abundance of papers addressing the suppressive effects of CD4+CD25+ regulatory T cells and their putative role in various experimental disease models and human diseases. Despite the enormous amounts of data on these cells a number of controversial issues still exists. CD4+CD25+ regulatory T cells were originally described as thymus-derived anergic/suppressive T cells. Recent papers however indicate that these cells might also be generated in the periphery. Due to the thymic development of CD4+CD25+ regulatory T cells it was thought that these cells were specific for self-antigens. Indeed it was shown that CD4+CD25+ regulatory T cells could be positively selected upon high affinity interaction with self-antigens. However, evidence is accumulating that these cells might also interact with non-self antigens. Finally, in the literature there is conflicting evidence regarding the role of soluble factors versus cell-contact in the mechanism of suppression. The aim of this review is to summarize the evidence supporting these opposing viewpoints and to combine them into a general model for the origin, function and antigen-specificity of CD4+CD25+ regulatory T cells.

  15. Discovery of T cell antigens by high-throughput screening of synthetic minigene libraries.

    PubMed

    Hondowicz, Brian D; Schwedhelm, Katharine V; Kas, Arnold; Tasch, Michael A; Rawlings, Crystal; Ramchurren, Nirasha; McIntosh, Martin; D'Amico, Leonard A; Sanda, Srinath; Standifer, Nathan E; Shendure, Jay; Stone, Brad

    2012-01-01

    The identification of novel T cell antigens is central to basic and translational research in autoimmunity, tumor immunology, transplant immunology, and vaccine design for infectious disease. However, current methods for T cell antigen discovery are low throughput, and fail to explore a wide range of potential antigen-receptor interactions. To overcome these limitations, we developed a method in which programmable microarrays are used to cost-effectively synthesize complex libraries of thousands of minigenes that collectively encode the content of hundreds of candidate protein targets. Minigene-derived mRNA are transfected into autologous antigen presenting cells and used to challenge complex populations of purified peripheral blood CD8+ T cells in multiplex, parallel ELISPOT assays. In this proof-of-concept study, we apply synthetic minigene screening to identify two novel pancreatic islet autoantigens targeted in a patient with Type I Diabetes. To our knowledge, this is the first successful screen of a highly complex, synthetic minigene library for identification of a T cell antigen. In principle, responses against the full protein complement of any tissue or pathogen can be assayed by this approach, suggesting that further optimization of synthetic libraries holds promise for high throughput antigen discovery.

  16. Crypt cells are involved in kin recognition in larval zebrafish.

    PubMed

    Biechl, Daniela; Tietje, Kristin; Gerlach, Gabriele; Wullimann, Mario F

    2016-04-18

    Zebrafish larvae imprint on visual and olfactory kin cues at day 5 and 6 postfertilization, respectively, resulting in kin recognition later in life. Exposure to non-kin cues prevents imprinting and kin recognition. Imprinting depends on MHC class II related signals and only larvae sharing MHC class II alleles can imprint on each other. Here, we analyzed which type of olfactory sensory neuron (OSN) detects kin odor. The single teleost olfactory epithelium harbors ciliated OSNs carrying OR and TAAR gene family receptors (mammals: main olfactory epithelium) and microvillous OSNs with V1R and V2R gene family receptors (mammals: vomeronasal organ). Additionally, teleosts exhibit crypt cells which possess microvilli and cilia. We used the activity marker pERK (phosphorylated extracellular signal regulated kinase) after stimulating 9 day old zebrafish larvae with either non-kin conspecific or food odor. While food odor activated both ciliated and microvillous OSNs, only the latter were activated by conspecific odor, crypt cells showed no activation to both stimuli. Then, we tested imprinted and non-imprinted larvae (full siblings) for kin odor detection. We provide the first direct evidence that crypt cells, and likely a subpopulation of microvillous OSNs, but not ciliated OSNs, play a role in detecting a kin odor related signal.

  17. Crypt cells are involved in kin recognition in larval zebrafish

    PubMed Central

    Biechl, Daniela; Tietje, Kristin; Gerlach, Gabriele; Wullimann, Mario F.

    2016-01-01

    Zebrafish larvae imprint on visual and olfactory kin cues at day 5 and 6 postfertilization, respectively, resulting in kin recognition later in life. Exposure to non-kin cues prevents imprinting and kin recognition. Imprinting depends on MHC class II related signals and only larvae sharing MHC class II alleles can imprint on each other. Here, we analyzed which type of olfactory sensory neuron (OSN) detects kin odor. The single teleost olfactory epithelium harbors ciliated OSNs carrying OR and TAAR gene family receptors (mammals: main olfactory epithelium) and microvillous OSNs with V1R and V2R gene family receptors (mammals: vomeronasal organ). Additionally, teleosts exhibit crypt cells which possess microvilli and cilia. We used the activity marker pERK (phosphorylated extracellular signal regulated kinase) after stimulating 9 day old zebrafish larvae with either non-kin conspecific or food odor. While food odor activated both ciliated and microvillous OSNs, only the latter were activated by conspecific odor, crypt cells showed no activation to both stimuli. Then, we tested imprinted and non-imprinted larvae (full siblings) for kin odor detection. We provide the first direct evidence that crypt cells, and likely a subpopulation of microvillous OSNs, but not ciliated OSNs, play a role in detecting a kin odor related signal. PMID:27087508

  18. Dscam-Mediated Cell Recognition Regulates Neural Circuit Formation

    PubMed Central

    Hattori, Daisuke; Millard, S. Sean; Wojtowicz, Woj M.; Zipursky, S. Lawrence

    2009-01-01

    The Dscam family of immunoglobulin cell surface proteins mediates recognition events between neurons that play an essential role in the establishment of neural circuits. The Drosophila Dscam1 locus encodes tens of thousands of cell surface proteins via alternative splicing. These isoforms exhibit exquisite isoform-specific binding in vitro that mediates homophilic repulsion in vivo. These properties provide the molecular basis for self-avoidance, an essential developmental mechanism that allows axonal and dendritic processes to uniformly cover their synaptic fields. In a mechanistically similar fashion, homophilic repulsion mediated by Drosophila Dscam2 prevents processes from the same class of cells from occupying overlapping synaptic fields through a process called tiling. Genetic studies in the mouse visual system support the view that vertebrate DSCAM also promotes both self-avoidance and tiling. By contrast, DSCAM and DSCAM-L promote layer-specific targeting in the chick visual system, presumably through promoting homophilic adhesion. The fly and mouse studies underscore the importance of homophilic repulsion in regulating neural circuit assembly, whereas the chick studies suggest that DSCA Mproteins may mediate a variety of different recognition events during wiring in a context-dependent fashion. PMID:18837673

  19. In vitro expansion of antigen-specific CD8(+) T cells distorts the T-cell repertoire.

    PubMed

    Koning, Dan; Costa, Ana I; Hasrat, Raiza; Grady, Bart P X; Spijkers, Sanne; Nanlohy, Nening; Keşmir, Can; van Baarle, Debbie

    2014-03-01

    Short-term in vitro expansion of antigen-specific T cells is an appreciated assay for the analysis of small memory T-cell populations. However, how well short-term expanded T cells represent the direct ex vivo situation remains to be elucidated. In this study we compared the clonality of Epstein-Barr virus (EBV) and cytomegalovirus (CMV)-specific CD8(+) T cells directly ex vivo and after in vitro stimulation with antigen. Our data show that the antigen-specific T cell repertoire significantly alters after in vitro culture. Clear shifts in clonotype hierarchy were observed, with the most dominant ex vivo clonotype decreasing after stimulation at the expense of several previously subdominant clonotypes. Notably, these alterations were more pronounced in polyclonal T-cell populations compared to mono- or oligoclonal repertoires. Furthermore, TCR diversity significantly increased after culture with antigen. These results suggest that the T-cell repertoire is highly subjective to variation after in vitro stimulation with antigen. Hence, although short-term expansion of T cells provides a simple and efficient tool to examine antigen-specific immune responses, caution is required if T-cell populations are expanded prior to detailed, clonotypic analyses or other repertoire-based investigations.

  20. Differential presentation of tumor antigen-derived epitopes by MHC-class I and antigen-positive tumor cells.

    PubMed

    Held, Gerhard; Neumann, Frank; Sturm, Christine; Kaestner, Lars; Dauth, Nina; de Bruijn, Diederik R; Renner, Christoph; Lipp, Peter; Pfreundschuh, Michael

    2008-10-15

    SSX2 is a member of the family of cancer/testis antigens. The SSX2 derived peptide SSX2(103-111) has been shown to be presented to cytotoxic T-lymphocytes (CTL) by Major-Histocompatibility (MHC) Class-I complexes after endogenous processing, more precisely by the allele HLA-A*0201. The HLA-A*0201- and SSX2-positive melanoma cell line SK-Mel-37 but not Me275 had been shown to elicit reactivity in SSX2(103-111) specific cytotoxic T-lymphocytes. To analyze the correlation between SSX2(103-111) presentation and T-cell stimulation, we intended to visualize presentation of SSX2(103-111) in these melanoma cell lines. Fab-antibodies were established from a human phage library with specificity for SSX2(103-111)/HLA-A*0201 complexes (but non-reactive with HLA-A*0201 or SSX2(103-111) alone) and used to visualize the presentation of SSX2(103-111) in the context of HLA-A*0201 by fluorescence microscopy. Presentation of SSX2(103-111) the context of HLA-A*0201 was demonstrated for the majority of SK-Mel-37, but for only a small fraction (<1%) of Me275 as indicated by a clear membrane-staining pattern in fluorescence microscopy. The presentation of SSX2(103-111) on SK-Mel37 and Me275, but not the expression of the SSX2 protein correlated with the capability of these cells to stimulate cells of an SSX2(103-111)-specific T-cell clone. MHC-peptide specific antibodies are a valuable tool for the analysis of antigenic peptides in the context of MHC-I molecules and for the structural definition of immunodominant epitopes.

  1. Variant antigenic peptide promotes cytotoxic T lymphocyte adhesion to target cells without cytotoxicity

    PubMed Central

    Shotton, David M.; Attaran, Amir

    1998-01-01

    Timelapse video microscopy has been used to record the motility and dynamic interactions between an H-2Db-restricted murine cytotoxic T lymphocyte clone (F5) and Db-transfected L929 mouse fibroblasts (LDb) presenting normal or variant antigenic peptides from human influenza nucleoprotein. F5 cells will kill LDb target cells presenting specific antigen (peptide NP68: ASNENMDAM) after “browsing” their surfaces for between 8 min and many hours. Cell death is characterized by abrupt cellular rounding followed by zeiosis (vigorous “boiling” of the cytoplasm and blebbing of the plasma membrane) for 10–20 min, with subsequent cessation of all activity. Departure of cytotoxic T lymphocytes from unkilled target cells is rare, whereas serial killing is sometimes observed. In the absence of antigenic peptide, cytotoxic T lymphocytes browse target cells for much shorter periods, and readily leave to encounter other targets, while never causing target cell death. Two variant antigenic peptides, differing in nonamer position 7 or 8, also act as antigens, albeit with lower efficiency. A third variant peptide NP34 (ASNENMETM), which differs from NP68 in both positions and yet still binds Db, does not stimulate F5 cytotoxicity. Nevertheless, timelapse video analysis shows that NP34 leads to a significant modification of cell behavior, by up-regulating F5–LDb adhesive interactions. These data extend recent studies showing that partial agonists may elicit a subset of the T cell responses associated with full antigen stimulation, by demonstrating that TCR interaction with variant peptide antigens can trigger target cell adhesion and surface exploration without activating the signaling pathway that results in cytotoxicity. PMID:9861010

  2. Predominant role for directly transfected dendritic cells in antigen presentation to CD8+ T cells after gene gun immunization.

    PubMed

    Porgador, A; Irvine, K R; Iwasaki, A; Barber, B H; Restifo, N P; Germain, R N

    1998-09-21

    Cutaneous gene (DNA) bombardment results in substantial expression of the encoded antigen in the epidermal layer as well as detectable expression in dendritic cells (DC) in draining lymph nodes (LNs). Under these conditions, two possible modes of DC antigen presentation to naive CD8+ T cells might exist: (a) presentation directly by gene-transfected DC trafficking to local lymph nodes, and (b) cross-presentation by untransfected DC of antigen released from or associated with transfected epidermal cells. The relative contributions of these distinct modes of antigen presentation to priming for cytotoxic T cell (CTL) responses have not been clearly established. Here we show that LN cells directly expressing the DNA-encoded antigen are rare; 24 h after five abdominal skin bombardments, the number of these cells does not exceed 50-100 cells in an individual draining LN. However, over this same time period, the total number of CD11c+ DC increases more than twofold, by an average of 20,000-30,000 DC per major draining node. This augmentation is due to gold bombardment and is independent of the presence of plasmid DNA. Most antigen-bearing cells in the LNs draining the site of DNA delivery appear to be DC and can be depleted by antibodies to an intact surface protein encoded by cotransfected DNA. This finding of predominant antigen presentation by directly transfected cells is also consistent with data from studies on cotransfection with antigen and CD86-encoding DNA, showing that priming of anti-mutant influenza nucleoprotein CTLs with a single immunization is dependent upon coexpression of the DNAs encoding nucleoprotein and B7.2 in the same cells. These observations provide insight into the relative roles of direct gene expression and cross-presentation in CD8+ T cell priming using gene gun immunization, and indicate that augmentation of direct DC gene expression may enhance such priming.

  3. Characterization of a double-CRD-mutated Gal-8 recombinant protein that retains co-stimulatory activity on antigen-specific T-cell response.

    PubMed

    Schroeder, Matías Nicolás; Tribulatti, María Virginia; Carabelli, Julieta; André-Leroux, Gwenaëlle; Caramelo, Julio Javier; Cattaneo, Valentina; Campetella, Oscar

    2016-04-01

    Galectins (Gals) constitute a family of mammalian lectins with affinity for β-galactosides, characterized by the presence of conserved CRDs (carbohydrate-recognition domains). We have found previously that Gal-8, from the tandem-repeat group with two linked CRDs, exerts two separate actions on CD4(+)T-cells: antigen-independent proliferation and, at lower concentration, antigen-specific co-stimulation. Whereas proliferation can be ascribed to the pro-inflammatory role of Gal-8, the co-stimulatory activity of borderline T-cell-specific responses allows the proposal of Gal-8 as an adjuvant in vaccination. To study the relevance of glycan-lectin interaction to these T-cell activities, we generated a double-mutated protein (Gal-8mut) by replacing canonical arginine residues on each CRD, so as to abolish sugar-binding capacity. As expected, Gal-8mut was unable to bind to lactosyl-Sepharose, confirming that lactose recognition was precluded; however, preservation of lectin activity was still evident since Gal-8mut displayed haemoagglutinatory effects and binding capacity to the T-cell surface. To search for glycan affinity, a glycan microarray analysis was conducted which revealed that Gal-8mut lost most low- and intermediate-, but retained high-, affinity interactions, mainly to polylactosamines and blood group antigens. These findings were supported further by molecular modelling. Regarding biological activity, Gal-8mut was unable to induce T-cell proliferation, but efficiently co-stimulated antigen-specific responses, bothin vitroandin vivo.Therefore Gal-8mut represents a useful tool to dissect the specificities of lectin-glycan interactions underlying distinctive Gal-8 activities on T-cell biology. Moreover, given its distinguishing properties, Gal-8mut could be used to enhance borderline immune responses without the non-specific pro-inflammatory activity or other potential adverse effects.

  4. CTLA4 mediates antigen-specific apoptosis of human T cells.

    PubMed Central

    Gribben, J G; Freeman, G J; Boussiotis, V A; Rennert, P; Jellis, C L; Greenfield, E; Barber, M; Restivo, V A; Ke, X; Gray, G S

    1995-01-01

    The regulation of T cell-mediated immune responses requires a balance between amplification and generation of effector function and subsequent selective termination by clonal deletion. Although apoptosis of previously activated T cells can be induced by signaling of the tumor necrosis factor receptor family, these molecules do not appear to regulate T-cell clonal deletion in an antigen-specific fashion. We demonstrate that cross-linking of the inducible T-cell surface molecule CTLA4 can mediate apoptosis of previously activated human T lymphocytes. This function appears to be antigen-restricted, since a concomitant signal T-cell receptor signal is required. Regulation of this pathway may provide a novel therapeutic strategy to delete antigen-specific activated T cells. Images Fig. 3 PMID:7846057

  5. Unmasking targets of T cell-mediated antitumor immunity through high-throughput antigen profiling

    PubMed Central

    Battaglia, Sebastiano; Muhitch, Jason B

    2017-01-01

    More than three decades of evidence has established that antitumor immune responses, initially shown with IL-2 treatment, can result in complete, durable eradication of malignant disease in metastatic patients. Recent studies have demonstrated that immune checkpoint blockade as well as cellular therapies, including dendritic cell activation of T cells and adoptive T cell transfer, can induce long-lasting responses. To elicit cytolysis of tumor cells, effector T cells rely on tumor expression of target antigens. However, the antigens targeted during antitumor responses are largely unknown. Technological advancements and availability of sequencing data have paved the way for more efficient screening and validation of tumor-associated antigens and neoantigens derived from non-synonymous mutations targeted by T cells under baseline conditions and in the context of immunotherapy. PMID:27010105

  6. Manipulating Antigenic Ligand Strength to Selectively Target Myelin-Reactive CD4+ T Cells in EAE

    PubMed Central

    Sabatino, Joseph J.; Rosenthal, Kristen M.

    2010-01-01

    The development of antigen-specific therapies for the selective tolerization of autoreactive T cells remains the Holy Grail for the treatment of T-cell-mediated autoimmune diseases such as multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE). This quest remains elusive, however, as the numerous antigen-specific strategies targeting myelin-specific T cells over the years have failed to result in clinical success. In this review, we revisit the antigen-based therapies used in the treatment of myelin-specific CD4+ T cells in the context of the functional avidity and the strength of signal of the encephalitogenic CD4+ T cell repertoire. In light of differences in activation thresholds, we propose that autoreactive T cells are not all equal, and therefore tolerance induction strategies must incorporate ligand strength in order to be successful in treating EAE and ultimately the human disease MS. PMID:19904613

  7. Estimation of low frequency antigen presenting cells with a novel RELISPOT assay

    PubMed Central

    Dzutsev, Amiran K.; Belyakov, Igor M.; Isakov, Dmitry V.; Gagnon, Susan J.; Margulies, David H.; Berzofsky, Jay A.

    2008-01-01

    Adequate presentation of self and foreign antigens is a key factor for efficient T-cell immunosurveillance against pathogens and tumors. Cells presenting foreign antigens usually comprise a rare population and are difficult to detect even at the peak of infection. Here we demonstrate a CD8+ T-cell-based approach that allows detection of specific antigen-presenting cells (APC) at a frequency of less than 0.0005%. When T cells are in excess, they form rosettes with rare APCs, which appear as single spots in an IFN-γ ELISPOT assay. Using this RELISPOT (Rosette ELISPOT) method we demonstrate the dynamic interplay between CD8 T cells and professional and non-professional APCs following virus challenge. PMID:18294650

  8. Human CD14 mediates recognition and phagocytosis of apoptotic cells.

    PubMed

    Devitt, A; Moffatt, O D; Raykundalia, C; Capra, J D; Simmons, D L; Gregory, C D

    1998-04-02

    Cells undergoing programmed cell death (apoptosis) are cleared rapidly in vivo by phagocytes without inducing inflammation. Here we show that the glycosylphosphatidylinositol-linked plasma-membrane glycoprotein CD14 on the surface of human macrophages is important for the recognition and clearance of apoptotic cells. CD14 can also act as a receptor that binds bacterial lipopolysaccharide (LPS), triggering inflammatory responses. Overstimulation of CD14 by LPS can cause the often fatal toxic-shock syndrome. Here we show that apoptotic cells interact with CD14, triggering phagocytosis of the apoptotic cells. This interaction depends on a region of CD14 that is identical to, or at least closely associated with, a region known to bind LPS. However, apoptotic cells, unlike LPS, do not provoke the release of pro-inflammatory cytokines from macrophages. These results indicate that clearance of apoptotic cells is mediated by a receptor whose interactions with 'non-self' components (LPS) and 'self' components (apoptotic cells) produce distinct macrophage responses.

  9. A novel human B-lymphocyte antigen shared with lymphoid dendritic cells: characterization by monoclonal antibody.

    PubMed Central

    Ishii, Y; Takami, T; Kokai, Y; Yuasa, H; Fujimoto, J; Takei, T; Kikuchi, K

    1985-01-01

    A novel cell-surface antigen (L25) expressed on human B cells was identified using a B cell-reactive monoclonal antibody (TB1-4D5). This L25 antigen was expressed on most B-lineage cells but not other cell types including thymocytes, T cells, granulocytes and monocytes. Thus, L25 existed on the majority of normal B cells present in the blood and lymphoid tissues, on cultured cell lines derived from normal and malignant B cells, and on neoplastic cells isolated from patients with B cell-derived malignancies. Though L25 was persistently expressed on B cells until 7 days after their activation with pokeweed mitogen (PWM), neither normal nor neoplastic plasma cells expressed L25. Moreover, L25 was present on cultured as well as freshly isolated leukaemic cells with common acute lymphatic leukaemia (CALL) antigen, which have been thought to correspond to the early B-cell ontogeny. Besides pan-B cell reactivity of TB1-4D5 antibody, it apparently cross-reacted with so-called dendritic or interdigitating cells located in the thymic-dependent areas of peripheral lymphoid organs, which have been presumably ascribed to those associated with accessory-cell function. Functional studies showed that anti-L25 (TB1-4D5) antibody had inhibitory effect on induction of immunoglobulin synthesis by PWM-stimulated B cells. Images Fig. 2 PMID:3907905

  10. Dendritic cells and parasites: from recognition and activation to immune response instruction.

    PubMed

    Motran, Claudia Cristina; Ambrosio, Laura Fernanda; Volpini, Ximena; Celias, Daiana Pamela; Cervi, Laura

    2017-02-01

    The effective defense against parasite infections requires the ability to mount an appropriate and controlled specific immune response able to eradicate the invading pathogen while limiting the collateral damage to self-tissues. Dendritic cells are key elements for the development of immunity against parasites; they control the responses required to eliminate these pathogens while maintaining host homeostasis. Ligation of dendritic cell pattern recognition receptors by pathogen-associated molecular pattern present in the parasites initiates signaling pathways that lead to the production of surface and secreted proteins that are required, together with the antigen, to induce an appropriate and timely regulated immune response. There is evidence showing that parasites can influence and regulate dendritic cell functions in order to promote a more permissive environment for their survival. In this review, we will focus on new insights about the ability of protozoan and helminth parasites or their products to modify dendritic cell function and discuss how this interaction is crucial in shaping the host response.

  11. A new Kupffer cell receptor mediating plasma clearance of carcinoembryonic antigen by the rat.

    PubMed Central

    Toth, C A; Thomas, P; Broitman, S A; Zamcheck, N

    1982-01-01

    Native human carcinoembryonic antigen is rapidly removed from the circulation by the rat liver Kupffer cell after intravenous injection. The molecule is subsequently transferred to the hepatocyte in an immunologically identifiable form. Carcinoembryonic antigen has a circulatory half-life of 3.7 (+/- 0.8) min, and cellular entry is by receptor-mediated endocytosis. Non-specific fluid pinocytosis and phagocytosis can be excluded as possible mechanisms by the kinetics of clearance and failure of colloidal carbon to inhibit uptake. Substances with known affinity for the hepatic receptors for mannose, N-acetylglucosamine, fucose and galactose all fail to inhibit carcinoembryonic antigen clearance. After two cycles of the Smith degradation, carcinoembryonic antigen is still able to inhibit clearance of the native molecule. Receptor specificity is apparently not dependent on those non-reducing terminal sugars of the native molecule. Performic acid-oxidized carcinoembryonic antigen also inhibits clearance of carcinoembryonic antigen in vivo. Receptor binding is not dependent on tertiary protein conformation. Non-specific cross-reacting antigen, a glycoprotein structurally similar to carcinoembryonic antigen, is cleared by the same mechanism. PMID:6896821

  12. A new Kupffer cell receptor mediating plasma clearance of carcinoembryonic antigen by the rat.

    PubMed

    Toth, C A; Thomas, P; Broitman, S A; Zamcheck, N

    1982-05-15

    Native human carcinoembryonic antigen is rapidly removed from the circulation by the rat liver Kupffer cell after intravenous injection. The molecule is subsequently transferred to the hepatocyte in an immunologically identifiable form. Carcinoembryonic antigen has a circulatory half-life of 3.7 (+/- 0.8) min, and cellular entry is by receptor-mediated endocytosis. Non-specific fluid pinocytosis and phagocytosis can be excluded as possible mechanisms by the kinetics of clearance and failure of colloidal carbon to inhibit uptake. Substances with known affinity for the hepatic receptors for mannose, N-acetylglucosamine, fucose and galactose all fail to inhibit carcinoembryonic antigen clearance. After two cycles of the Smith degradation, carcinoembryonic antigen is still able to inhibit clearance of the native molecule. Receptor specificity is apparently not dependent on those non-reducing terminal sugars of the native molecule. Performic acid-oxidized carcinoembryonic antigen also inhibits clearance of carcinoembryonic antigen in vivo. Receptor binding is not dependent on tertiary protein conformation. Non-specific cross-reacting antigen, a glycoprotein structurally similar to carcinoembryonic antigen, is cleared by the same mechanism.

  13. Identification of bovine T-cell epitopes for three Mycobacterium bovis antigens: MPB70, 19,000 MW and MPB57.

    PubMed Central

    Pollock, J M; Douglas, A J; Mackie, D P; Neill, S D

    1994-01-01

    Bovine tuberculosis remains a serious problem in several regions, partly due to a lack of specific diagnostic tests. The aim of this study was to identify bovine T-cell epitopes for defined Mycobacterium bovis antigens using an experimental model of the natural disease. Panels of synthetic peptides (16-mers with five residue overlaps) were produced from published amino acid sequences for MPB70, the 19,000 MW antigen and MPB57. In vitro lymphocyte proliferation assays were used to identify T-cell epitopes. Lymphocytes from experimentally infected cattle proliferated in response to five epitopes (residues 88-105 and 144-163 for MPB70; 1-16 and 67-84 for the 19,000 MW antigen; and 85-100 for MBP57). These epitopes were not recognized by control, non-infected animals, but were recognized by field reactors to intradermal tuberculin testing. All five epitopes were recognized by three different breeds of cattle (Friesian, Charolais and Simmental). In addition, the bovine T-cell epitopes identified for the 19,000 MW antigen in this study were similar to epitopes previously reported for man and mouse. Thus, as well as identifying candidate reagents for improved diagnostic tests and vaccination, this study provides evidence for genetic promiscuity T-cell recognition of major myobacterial epitopes. PMID:7519175

  14. Application of the pMHC Array to Characterise Tumour Antigen Specific T Cell Populations in Leukaemia Patients at Disease Diagnosis.

    PubMed

    Brooks, Suzanne E; Bonney, Stephanie A; Lee, Cindy; Publicover, Amy; Khan, Ghazala; Smits, Evelien L; Sigurdardottir, Dagmar; Arno, Matthew; Li, Demin; Mills, Ken I; Pulford, Karen; Banham, Alison H; van Tendeloo, Viggo; Mufti, Ghulam J; Rammensee, Hans-Georg; Elliott, Tim J; Orchard, Kim H; Guinn, Barbara-ann

    2015-01-01

    Immunotherapy treatments for cancer are becoming increasingly successful, however to further improve our understanding of the T-cell recognition involved in effective responses and to encourage moves towards the development of personalised treatments for leukaemia immunotherapy, precise antigenic targets in individual patients have been identified. Cellular arrays using peptide-MHC (pMHC) tetramers allow the simultaneous detection of different antigen specific T-cell populations naturally circulating in patients and normal donors. We have developed the pMHC array to detect CD8+ T-cell populations in leukaemia patients that recognise epitopes within viral antigens (cytomegalovirus (CMV) and influenza (Flu)) and leukaemia antigens (including Per Arnt Sim domain 1 (PASD1), MelanA, Wilms' Tumour (WT1) and tyrosinase). We show that the pMHC array is at least as sensitive as flow cytometry and has the potential to rapidly identify more than 40 specific T-cell populations in a small sample of T-cells (0.8-1.4 x 10(6)). Fourteen of the twenty-six acute myeloid leukaemia (AML) patients analysed had T cells that recognised tumour antigen epitopes, and eight of these recognised PASD1 epitopes. Other tumour epitopes recognised were MelanA (n = 3), tyrosinase (n = 3) and WT1(126-134) (n = 1). One of the seven acute lymphocytic leukaemia (ALL) patients analysed had T cells that recognised the MUC1(950-958) epitope. In the future the pMHC array may be used provide point of care T-cell analyses, predict patient response to conventional therapy and direct personalised immunotherapy for patients.

  15. Demonstration of common antigens on cell surface of Clostridium chauvoei and C. septicum by indirect-immunofluorescence assay.

    PubMed

    Hamaoka, T; Terakado, N

    1994-04-01

    The common antigens between Clostridium chauvoei and C. septicum were examined by indirect-immunofluorescence assay (IFA). Antisera to formalized cells of C. chauvoei and C. septicum strains and to EDTA-soluble antigens of these strains were used. The antisera to formalized cells, which have reacted only with homologous antigens in agglutination tests, reacted not only with homologous antigens but also with heterologous antigens in IFA. The antisera to EDTA-soluble antigens, which have shown no reactivities in somatic agglutination tests, reached with both homologous and heterologous antigens in IFA. These results indicate that these species possess common antigens, which are undetected by agglutination tests, on the cell surface and a some of them are solubilized by EDTA-treatment.

  16. Neutrophils acquire the capacity for antigen presentation to memory CD4(+) T cells in vitro and ex vivo.

    PubMed

    Vono, Maria; Lin, Ang; Norrby-Teglund, Anna; Koup, Richard A; Liang, Frank; Loré, Karin

    2017-04-06

    Neutrophils are critical cells of the innate immune system and rapidly respond to tissue injury and infection. Increasing evidence also indicates that neutrophils have versatile functions in contributing to adaptive immunity by internalizing and transporting antigen and influencing antigen-specific responses. Here, we demonstrate that freshly isolated human neutrophils can function as antigen-presenting cells (APCs) to memory CD4(+) T cells. Neutrophils pulsed with the cognate antigens cytomegalovirus pp65 or influenza hemagglutinin were able to present the antigens to autologous antigen-specific CD4(+) T cells in a major histocompatibility complex class II (MHC-II; HLA-DR)-dependent manner. Although myeloid dendritic cells and monocytes showed superior presenting ability, neutrophils consistently displayed antigen presentation capability. Upregulation of HLA-DR on neutrophils required the presence of the antigen-specific or activated T cells whereas exposure to innate stimuli such as Toll-like receptor ligands was not sufficient. Neutrophils sorted from vaccine-draining lymph nodes from rhesus macaques also showed expression of HLA-DR and were capable of presenting vaccine antigen to autologous antigen-specific memory CD4(+) T cells ex vivo. Altogether, the data demonstrate that neutrophils can adapt a function as APCs and, in combination with their abundance in the immune system, may have a significant role in regulating antigen-specific T-cell responses.

  17. Classical dendritic cells are required for dietary antigen-mediated peripheral regulatory T cell and tolerance induction

    PubMed Central

    Esterházy, Daria; Loschko, Jakob; London, Mariya; Jove, Veronica; Oliveira, Thiago Y.; Mucida, Daniel

    2016-01-01

    Oral tolerance prevents pathological inflammatory responses towards innocuous foreign antigens via peripheral regulatory T cells (pTreg cells). However, whether a particular subset of antigen-presenting cells (APCs) is required during dietary antigen exposure to instruct naïve CD4+ T cells to differentiate into pTreg cells has not been defined. Using myeloid lineage-specific APC depletion in mice, we found that monocyte-derived APCs are dispensable, while classical dendritic cells (cDCs) are critical for pTreg cell induction and oral tolerance. CD11b− cDCs from the gut-draining lymph nodes efficiently induced pTreg cells, and conversely, loss of IRF8-dependent CD11b− cDCs impaired their polarization, although oral tolerance remained intact. These data reveal the hierarchy of cDC subsets in pTreg cell induction and their redundancy during oral tolerance development. PMID:27019226

  18. Promiscuous CTL recognition of viral epitopes on multiple human leukocyte antigens: biological validation of the proposed HLA A24 supertype.

    PubMed

    Burrows, Scott R; Elkington, Rebecca A; Miles, John J; Green, Katherine J; Walker, Susan; Haryana, Sofia M; Moss, Denis J; Dunckley, Heather; Burrows, Jacqueline M; Khanna, Rajiv

    2003-08-01

    Multiple HLA class I alleles can bind peptides with common sequence motifs due to structural similarities in the peptide binding cleft, and these groups of alleles have been classified into supertypes. Nine major HLA supertypes have been proposed, including an A24 supertype that includes A*2301, A*2402, and A*3001. Evidence for this A24 supertype is limited to HLA sequence homology and/or similarity in peptide binding motifs for the alleles. To investigate the immunological relevance of this proposed supertype, we have examined two viral epitopes (from EBV and CMV) initially defined as HLA-A*2301-binding peptides. The data clearly demonstrate that each peptide could be recognized by CTL clones in the context of A*2301 or A*2402; thus validating the inclusion of these three alleles within an A24 supertype. Furthermore, CTL responses to the EBV epitope were detectable in both A*2301(+) and A*2402(+) individuals who had been previously exposed to this virus. These data substantiate the biological relevance of the A24 supertype, and the identification of viral epitopes with the capacity to bind promiscuously across this supertype could aid efforts to develop CTL-based vaccines or immunotherapy. The degeneracy in HLA restriction displayed by some T cells in this study also suggests that the dogma of self-MHC restriction needs some refinement to accommodate foreign peptide recognition in the context of multiple supertype alleles.

  19. Tubulin and Actin Interplay at the T Cell and Antigen-Presenting Cell Interface

    PubMed Central

    Martín-Cófreces, Noa Beatriz; Alarcón, Balbino; Sánchez-Madrid, Francisco

    2011-01-01

    T cells reorganize their actin and tubulin-based cytoskeletons to provide a physical basis to the immune synapse. However, growing evidence shows that their roles on T cell activation are more dynamic than merely serving as tracks or scaffold for different molecules. The crosstalk between both skeletons may be important for the formation and movement of the lamella at the immunological synapse by increasing the adhesion of the T cell to the antigen-presenting cells (APC), thus favoring the transport of components toward the plasma membrane and in turn regulating the T-APC intercellular communication. Microtubules and F-actin appear to be essential for the transport of the different signaling microclusters along the membrane, therefore facilitating the propagation of the signal. Finally, they can also be important for regulating the endocytosis, recycling, and degradation of the T cell receptor signaling machinery, thus helping both to sustain the activated state and to switch it off. PMID:22566814

  20. Reduction of T-Helper Cell Responses to Recall Antigen Mediated by Codelivery with Peptidoglycan via the Intestinal Nanomineral–Antigen Pathway

    PubMed Central

    Hewitt, Rachel E.; Robertson, Jack; Haas, Carolin T.; Pele, Laetitia C.; Powell, Jonathan J.

    2017-01-01

    Naturally occurring intestinal nanomineral particles constituently form in the mammalian gut and trap luminal protein and microbial components. These cargo loaded nanominerals are actively scavenged by M cells of intestinal immune follicles, such as Peyer’s patches and are passed to antigen-presenting cells. Using peripheral blood mononuclear cell populations as an in vitro model of nanomineral uptake and antigen presentation, we show that monocytes avidly phagocytose nanomineral particles bearing antigen and peptidoglycan (PGN), and that the presence of PGN within particles downregulates their cell surface MHC class II and upregulates programmed death receptor ligand 1. Nanomineral delivery of antigen suppresses antigen-specific CD4+ T cell responses, an effect that is enhanced in the presence of PGN. Blocking the interleukin-10 receptor restores CD4+ T cell responses to antigen codelivered with PGN in nanomineral form. Using human intestinal specimens, we have shown that the in vivo nanomineral pathway operates in an interleukin-10 rich environment. Consequently, the delivery of a dual antigen–PGN cargo by endogenous nanomineral in vivo is likely to be important in the establishment of intestinal tolerance, while their synthetic mimetics present a potential delivery system for therapeutic applications targeting the modulation of Peyer’s patch T cell responses. PMID:28367148

  1. IP-10 Is a Sensitive Biomarker of Antigen Recognition in Whole-Blood Stimulation Assays Used for the Diagnosis of Mycobacterium bovis Infection in African Buffaloes (Syncerus caffer).

    PubMed

    Goosen, Wynand J; Cooper, David; Miller, Michele A; van Helden, Paul D; Parsons, Sven D C

    2015-08-01

    African buffaloes (Syncerus caffer) are maintenance hosts of Mycobacterium bovis, the causative agent of bovine tuberculosis. They act as reservoirs of this infection for a wide range of wildlife and domestic species, and the detection of infected animals is important to control the geographic spread and transmission of the disease. Interferon gamma (IFN-γ) release assays (IGRAs) utilizing pathogen-derived peptide antigens are highly specific tests of M. bovis infection; however, the diagnostic sensitivities of these assays are suboptimal. We evaluated the diagnostic utility of measuring antigen-dependent interferon gamma-induced protein 10 (IP-10) release as an alternative to measuring IFN-γ levels. M. bovis-exposed buffaloes were tested using the Bovigam PC-EC and Bovigam PC-HP assays and a modified QuantiFERON TB-Gold (mQFT) assay. IP-10 was measured in the harvested plasma and was produced in significantly greater abundance in response to M. bovis antigens in Bovigam-positive than in Bovigam-negative animals. For each assay, using the Bovigam results as a reference, receiver operating characteristic curve analysis was done to determine diagnostically relevant cutoff values for IP-10. Thereafter, mQFT test results derived from measurement of IP-10 and IFN-γ were compared and a larger number of Bovigam-positive animals were detected using IP-10 as a diagnostic marker. Moreover, using IP-10, agreement between the mQFT assay and the Bovigam assays was increased, while the excellent agreement between the Bovigam assays was retained. We conclude that IP-10 is a sensitive marker of antigen recognition and that measurement of this cytokine in antigen-stimulated whole blood might increase the sensitivity of conventional IGRAs in African buffaloes.

  2. Diverse endogenous antigens for mouse NKT cells: self-antigens that are not glycosphingolipids.

    PubMed

    Pei, Bo; Speak, Anneliese O; Shepherd, Dawn; Butters, Terry; Cerundolo, Vincenzo; Platt, Frances M; Kronenberg, Mitchell

    2011-02-01

    NKT cells with an invariant Ag receptor (iNKT cells) represent a highly conserved and unique subset of T lymphocytes having properties of innate and adaptive immune cells. They have been reported to regulate a variety of immune responses, including the response to cancers and the development of autoimmunity. The development and activation of iNKT cells is dependent on self-Ags presented by the CD1d Ag-presenting molecule. It is widely believed that these self-Ags are glycosphingolipids (GSLs), molecules that contain ceramide as the lipid backbone. In this study, we used a variety of methods to show that mammalian Ags for mouse iNKT cells need not be GSLs, including the use of cell lines deficient in GSL biosynthesis and an inhibitor of GSL biosynthesis. Presentation of these Ags required the expression of CD1d molecules that could traffic to late endosomes, the site where self-Ag is acquired. Extracts of APCs contain a self-Ag that could stimulate iNKT cells when added to plates coated with soluble, rCD1d molecules. The Ag(s) in these extracts are resistant to sphingolipid-specific hydrolase digestion, consistent with the results using live APCs. Lyosphosphatidylcholine, a potential self-Ag that activated human iNKT cell lines, did not activate mouse iNKT cell hybridomas. Our data indicate that there may be more than one type of self-Ag for iNKT cells, that the self-Ags comparing mouse and human may not be conserved, and that the search to identify these molecules should not be confined to GSLs.

  3. Rheumatoid arthritis and its association with HLA-DR antigens. I. Cell mediated immune response against connective tissue antigens.

    PubMed

    Vullo, C M; Pesoa, S A; Onetti, C M; Riera, C M

    1987-04-01

    HLA-DR antigens and cellular sensitivity to native bovine type I and type II collagen and proteoglycans were examined in patients with classic rheumatoid arthritis (RA) and normal individuals. Fifty eight percent of patients with RA (n = 88) and 28% of normals (n = 52) were DR4+ (pc less than 0.01). DR4 phenotype was significantly increased in patients with severe disease stages (III-IV), as defined by the ARA criteria, in contrast to those showing mild disease stages (I-II) (p less than 0.05). Furthermore, peripheral blood mononuclear cells from 55 patients and 30 controls were evaluated for the in vitro production of leukocyte inhibitory factor in response to native type I and type II collagen and proteoglycans. By using this assay, cells from the arthritic group exhibited a statistically significant response when stimulated with native type I collagen and proteoglycans. The cellular immune response was not associated with any particular HLA-DR antigens, or to the disease stage or severity.

  4. Merkel Cell Polyomavirus Small T Antigen Mediates Microtubule Destabilization To Promote Cell Motility and Migration

    PubMed Central

    Knight, Laura M.; Stakaityte, Gabriele; Wood, Jennifer, J.; Abdul-Sada, Hussein; Griffiths, David A.; Howell, Gareth J.; Wheat, Rachel; Blair, G. Eric; Steven, Neil M.; Macdonald, Andrew; Blackbourn, David J.

    2014-01-01

    ABSTRACT Merkel cell carcinoma (MCC) is an aggressive skin cancer of neuroendocrine origin with a high propensity for recurrence and metastasis. Merkel cell polyomavirus (MCPyV) causes the majority of MCC cases due to the expression of the MCPyV small and large tumor antigens (ST and LT, respectively). Although a number of molecular mechanisms have been attributed to MCPyV tumor antigen-mediated cellular transformation or replication, to date, no studies have investigated any potential link between MCPyV T antigen expression and the highly metastatic nature of MCC. Here we use a quantitative proteomic approach to show that MCPyV ST promotes differential expression of cellular proteins implicated in microtubule-associated cytoskeletal organization and dynamics. Intriguingly, we demonstrate that MCPyV ST expression promotes microtubule destabilization, leading to a motile and migratory phenotype. We further highlight the essential role of the microtubule-associated protein stathmin in MCPyV ST-mediated microtubule destabilization and cell motility and implicate the cellular phosphatase catalytic subunit protein phosphatase 4C (PP4C) in the regulation of this process. These findings suggest a possible molecular mechanism for the highly metastatic phenotype associated with MCC. IMPORTANCE Merkel cell polyomavirus (MCPyV) causes the majority of cases of Merkel cell carcinoma (MCC), an aggressive skin cancer with a high metastatic potential. However, the molecular mechanisms leading to virally induced cancer development have yet to be fully elucidated. In particular, no studies have investigated any potential link between the virus and the highly metastatic nature of MCC. We demonstrate that the MCPyV small tumor antigen (ST) promotes the destabilization of the host cell microtubule network, which leads to a more motile and migratory cell phenotype. We further show that MCPyV ST induces this process by regulating the phosphorylation status of the cellular microtubule

  5. Plasmacytoid dendritic cells induce tolerance predominantly by cargoing antigen to lymph nodes

    PubMed Central

    Kohli, Karan; Janssen, Anika

    2016-01-01

    Plasmacytoid dendritic cells (pDCs) have been shown to induce tolerance to innocuous antigens. Their migratory properties allow them to take up antigens from the periphery and transport them to the draining lymph nodes or to the thymus. However, pDC‐T‐cell interaction in the primary and secondary lymphoid organs still remains poorly defined. In this study, we show that resting pDCs loaded with exogenous antigen could induce tolerance when transferred intralymphatically into a single lymph node of wild‐type C57BL/6 mice. However, this was a result of antigen transfer from pDCs to endogenous antigen presenting cells and subsequent abortive proliferation of cognate CD4+ T cells. pDCs could not directly induce the proliferation of CD4+ T cells, as observed in mice lacking MHC class II gene. Moreover, pDCs failed to make physical contacts with OT‐II cells as revealed by two‐photon imaging. Thus, the role of resting pDCs in tolerance induction seems to be independent of its direct interaction with cognate CD4+ T cells. PMID:27592607

  6. Ia antigens are expressed on ATPase-positive dendritic cells in chicken epidermis.

    PubMed Central

    Pérez Torres, A; Millan Aldaco, D A

    1994-01-01

    Langerhans cells (LC) are antigen-presenting dendritic cells located in mammalian epidermis and in other stratified epithelia. We recently demonstrated the presence of Langerhans-like cells in the epidermis of the chicken using ultrastructural histochemistry for adenosine triphosphatase (ATPase). The aim of the present study was to test whether ATPase-positive dendritic cells also express class II histocompatibility molecules (Ia antigens) encoded by the major histocompatibility complex (MHC), using a double staining technique, in separated chicken epidermal sheets. We concluded that the epidermal dendritic cells observed are the LC of the chicken, based on their morphology and spatial distribution, but mainly on the complete overlap for ATPase reaction and Ia antigen expression, these being reliable markers for the identification of mammalian LC. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Figs 7,8 Figs 9,10 Figs 11,12 PMID:7928646

  7. Extensive Polymorphism and Evidence of Immune Selection in a Highly Dominant Antigen Recognized by Bovine CD8 T Cells Specific for Theileria annulata▿†‖

    PubMed Central

    MacHugh, Niall D.; Weir, William; Burrells, Alison; Lizundia, Regina; Graham, Simon P.; Taracha, Evans L.; Shiels, Brian R.; Langsley, Gordon; Morrison, W. Ivan

    2011-01-01

    Although parasite strain-restricted CD8 T cell responses have been described for several protozoa, the precise role of antigenic variability in immunity is poorly understood. The tick-borne protozoan parasite Theileria annulata infects leukocytes and causes an acute, often fatal lymphoproliferative disease in cattle. Building on previous evidence of strain-restricted CD8 T cell responses to T. annulata, this study set out to identify and characterize the variability of the target antigens. Three antigens were identified by screening expressed parasite cDNAs with specific CD8 T cell lines. In cattle expressing the A10 class I major histocompatibility complex haplotype, A10-restricted CD8 T cell responses were shown to be focused entirely on a single dominant epitope in one of these antigens (Ta9). Sequencing of the Ta9 gene from field isolates of T. annulata demonstrated extensive sequence divergence, resulting in amino acid polymorphism within the A10-restricted epitope and a second A14-restricted epitope. Statistical analysis of the allelic sequences revealed evidence of positive selection for amino acid substitutions within the region encoding the CD8 T cell epitopes. Sequence differences in the A10-restricted epitope were shown to result in differential recognition by individual CD8 T cell clones, while clones also differed in their ability to recognize different alleles. Moreover, the representation of these clonal specificities within the responding CD8 T cell populations differed between animals. As well as providing an explanation for incomplete protection observed after heterologous parasite challenge of vaccinated cattle, these results have important implications for the choice of antigens for the development of novel subunit vaccines. PMID:21300773

  8. Chemical cross-linking of HIV-1 Env for direct TLR7/8 ligand conjugation compromises recognition of conserved antigenic determinants

    PubMed Central

    Feng, Yu; Forsell, Mattias N. E.; Flynn, Barbara; Adams, William; Loré, Karin; Seder, Robert; Wyatt, Richard T.; Karlsson Hedestam, Gunilla B.

    2013-01-01

    Covalent conjugation of immune-stimulatory compounds to protein antigens is a potential means to self-adjuvant non-replicating subunit vaccines. Previously, it was demonstrated that covalent coupling of a Toll-like receptor (TLR) ligand to the exterior HIV-1 envelope glycoprotein, gp120, enhanced its immunogenicity. However, the consequences of chemical conjugation to gp120 on broadly neutralizing antibody (bNAb) epitopes were so far not examined. Here, we conjugated a TLR7/8 ligand to lysine residues on gp120 using NHS-PEO8-maleimide linkers and investigated if this affected Ab recognition of the CD4 binding site (CD4bs), a highly conserved target for bNAbs. We demonstrate that the recognition of the CD4bs was reduced following coupling, especially at a higher coupling ratio. These results have implications for the coupling of ligands to vaccine antigens where elicitation of humoral immune responses to specific neutralizing determinants is desired. PMID:24074567

  9. Defining the HLA class I‐associated viral antigen repertoire from HIV‐1‐infected human cells

    PubMed Central

    Yang, Hongbing; Partridge, Thomas; Llano, Anuska; Cedeño, Samandhy; Fischer, Roman; Charles, Philip D.; Dudek, Nadine L.; Mothe, Beatriz; Crespo, Manuel; Fischer, William M.; Korber, Bette T. M.; Nielsen, Morten; Borrow, Persephone; Purcell, Anthony W.; Brander, Christian; Dorrell, Lucy; Kessler, Benedikt M.; Hanke, Tomáš

    2015-01-01

    Recognition and eradication of infected cells by cytotoxic T lymphocytes is a key defense mechanism against intracellular pathogens. High‐throughput definition of HLA class I‐associated immunopeptidomes by mass spectrometry is an increasingly important analytical tool to advance our understanding of the induction of T‐cell responses against pathogens such as HIV‐1. We utilized a liquid chromatography tandem mass spectrometry workflow including de novo‐assisted database searching to define the HLA class I‐associated immunopeptidome of HIV‐1‐infected human cells. We here report for the first time the identification of 75 HIV‐1‐derived peptides bound to HLA class I complexes that were purified directly from HIV‐1‐infected human primary CD4+ T cells and the C8166 human T‐cell line. Importantly, one‐third of eluted HIV‐1 peptides had not been previously known to be presented by HLA class I. Over 82% of the identified sequences originated from viral protein regions for which T‐cell responses have previously been reported but for which the precise HLA class I‐binding sequences have not yet been defined. These results validate and expand the current knowledge of virus‐specific antigenic peptide presentation during HIV‐1 infection and provide novel targets for T‐cell vaccine development. PMID:26467324

  10. Linking the T cell receptor to the single cell transcriptome in antigen-specific human T cells.

    PubMed

    Eltahla, Auda A; Rizzetto, Simone; Pirozyan, Mehdi R; Betz-Stablein, Brigid D; Venturi, Vanessa; Kedzierska, Katherine; Lloyd, Andrew R; Bull, Rowena A; Luciani, Fabio

    2016-07-01

    Heterogeneity of T cells is a hallmark of a successful adaptive immune response, harnessing the vast diversity of antigen-specific T cells into a coordinated evolution of effector and memory outcomes. The T cell receptor (TCR) repertoire is highly diverse to account for the highly heterogeneous antigenic world. During the response to a virus multiple individual clones of antigen specific CD8+ (Ag-specific) T cells can be identified against a single epitope and multiple epitopes are recognised. Advances in single-cell technologies have provided the potential to study Ag-specific T cell heterogeneity at both surface phenotype and transcriptome levels, thereby allowing investigation of the diversity within the same apparent sub-population. We propose a new method (VDJPuzzle) to reconstruct the native TCRαβ from single cell RNA-seq data of Ag-specific T cells and then to link these with the gene expression profile of individual cells. We applied this method using rare Ag-specific T cells isolated from peripheral blood of a subject who cleared hepatitis C virus infection. We successfully reconstructed productive TCRαβ in 56 of a total of 63 cells (89%), with double α and double β in 18, and 7% respectively, and double TCRαβ in 2 cells. The method was validated via standard single cell PCR sequencing of the TCR. We demonstrate that single-cell transcriptome analysis can successfully distinguish Ag-specific T cell populations sorted directly from resting memory cells in peripheral blood and sorted after ex vivo stimulation. This approach allows a detailed analysis of the TCR diversity and its relationship with the transcriptional profile of different clones.

  11. Spatiotemporally separated antigen uptake by alveolar dendritic cells and airway presentation to T cells in the lung

    PubMed Central

    Thornton, Emily E.; Looney, Mark R.; Bose, Oishee; Sen, Debasish; Sheppard, Dean; Locksley, Richard; Huang, Xiaozhu

    2012-01-01

    Asthma pathogenesis is focused around conducting airways. The reasons for this focus have been unclear because it has not been possible to track the sites and timing of antigen uptake or subsequent antigen presentation to effector T cells. In this study, we use two-photon microscopy of the lung parenchyma and note accumulation of CD11b+ dendritic cells (DCs) around the airway after allergen challenge but very limited access of these airway-adjacent DCs to the contents of the airspace. In contrast, we observed prevalent transepithelial uptake of particulate antigens by alveolar DCs. These distinct sites are temporally linked, as early antigen uptake in alveoli gives rise to DC and antigen retention in the airway-adjacent region. Antigen-specific T cells also accumulate in the airway-adjacent region after allergen challenge and are activated by the accumulated DCs. Thus, we propose that later airway hyperreactivity results from selective retention of allergen-presenting DCs and antigen-specific T cells in airway-adjacent interaction zones, not from variation in the abilities of individual DCs to survey the lung. PMID:22585735

  12. Murine T-Cell Response to Native and Recombinant Protein Antigens of Rickettsia Tsutsugamushi

    DTIC Science & Technology

    1993-02-01

    Wright, and J. Sadoff. 1985. 18-kilodalton protein of Mycobacterium leprae recognized by Immunoenzymatic analysis by monoclonal antibodies of bacte- Vo...determinants and closely resembles T-cell antigenic determinants, Rothbard and Taylor, by the GroEL homolog (65 kDa) of Mycobacterium tuberculo- analysis of...not be completely present in protein that is recognized by 20% of the mycobacterium - peptide 91-110. If this were the core of the antigenic deter

  13. Alloantigen-specific regulatory T cells generated with a chimeric antigen receptor.

    PubMed

    MacDonald, Katherine G; Hoeppli, Romy E; Huang, Qing; Gillies, Jana; Luciani, Dan S; Orban, Paul C; Broady, Raewyn; Levings, Megan K

    2016-04-01

    Adoptive immunotherapy with regulatory T cells (Tregs) is a promising treatment for allograft rejection and graft-versus-host disease (GVHD). Emerging data indicate that, compared with polyclonal Tregs, disease-relevant antigen-specific Tregs may have numerous advantages, such as a need for fewer cells and reduced risk of nonspecific immune suppression. Current methods to generate alloantigen-specific Tregs rely on expansion with allogeneic antigen-presenting cells, which requires access to donor and recipient cells and multiple MHC mismatches. The successful use of chimeric antigen receptors (CARs) for the generation of antigen-specific effector T cells suggests that a similar approach could be used to generate alloantigen-specific Tregs. Here, we have described the creation of an HLA-A2-specific CAR (A2-CAR) and its application in the generation of alloantigen-specific human Tregs. In vitro, A2-CAR-expressing Tregs maintained their expected phenotype and suppressive function before, during, and after A2-CAR-mediated stimulation. In mouse models, human A2-CAR-expressing Tregs were superior to Tregs expressing an irrelevant CAR at preventing xenogeneic GVHD caused by HLA-A2+ T cells. Together, our results demonstrate that use of CAR technology to generate potent, functional, and stable alloantigen-specific human Tregs markedly enhances their therapeutic potential in transplantation and sets the stage for using this approach for making antigen-specific Tregs for therapy of multiple diseases.

  14. Production kinetics and immunochemical properties of carcinoembryonic antigen and nonspecific cross-reacting antigen synthesized by various human tumor cell lines.

    PubMed

    Ichiki, S; Kuroki, M; Kuroki, M; Koga, Y; Matsuoka, Y

    1986-05-01

    The production kinetics and immunochemical properties of carcinoembryonic antigen (CEA) and nonspecific cross-reacting antigen (NCA) in various human tumor cell lines were studied. By radioimmunoassay (RIA), five CEA-producing tumor cell lines tested--2 derived from colonic (M7609 and CCK-81), one from pancreatic (QGP-1) and 2 from lung (HLC-1 and KNS-62) carcinomas--were found to produce NCA simultaneously. The cellular contents of CEA and NCA and the amounts of both antigens released into the culture medium were highly variable among the cell lines. It was a distinct contrast that one cell line (CCK-81) released very large amounts of CEA and NCA into the medium while having the smallest amounts of both antigens in the cells, whereas the others contained much larger amounts of the antigens in the cells as compared with the amounts released into the medium. For most of the cell lines, the production of both CEA and NCA increased in the stationary phase of growth as compared with the exponential phase. The production kinetics of both CEA and NCA appeared to be parallel with each other in all the cell lines, though the amount ratio of CEA to NCA produced was variable. By means of a double immunodiffusion test with polyclonal antibodies, antigenic uniformity with no unique organ-specificity was confirmed for all the CEA preparations from spent media of the cell lines, though some differences in the sugar moiety of CEA were detected by RIA using monoclonal antibodies. No antigenic differences among NCA preparations were observed. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), molecular heterogeneity was observed among CEA or NCA preparations isolated from cell lysates.

  15. Quantitative immunophenotypic analysis of antigen-presenting cells involved in ectromelia virus antigen presentation in BALB/c and C57BL/6 mice.

    PubMed

    Szulc-Dąbrowska, Lidia; Gieryńska, Małgorzata; Boratyńska-Jasińska, Anna; Martyniszyn, Lech; Winnicka, Anna; Niemiałtowski, Marek G

    2013-08-01

    During mousepox in resistant (C57BL/6) or susceptible (BALB/c) strains of mice, stimulation of Th1 or Th2 cytokine immune response, respectively, is observed. Because mechanisms of different polarization of T cells remain elusive, in this study, we quantitatively assessed the phenotype of antigen-presenting cells (APCs) involved in ectromelia virus (ECTV) antigen presentation and cluster formation with effector cells in secondary lymphoid organs of BALB/c and C57BL/6 mice. We showed that both strains of mice display similar dynamics and kinetics of viral antigen presentation by CD11c(+) , CD11b(+) , and CD19(+) cells. CD11c(+) and CD11b(+) cells highly participated in viral antigen presentation during all stages of mousepox, whereas CD19(+) cells presented viral peptides later in infection. The main population of dendritic cells (DCs) engaged in ECTV antigen presentation and cell junction formation with effector cells was a population of myeloid CD11b(+) DCs (mDCs). We suggest that, on the one hand, ECTV may differentially affect the functions of APCs depending on the strain of mice. On the other hand, we suggest that some types of APCs, such as mDCs or other DCs subsets, have different abilities to direct the shape of immune response depending on the host resistance to mousepox.

  16. Pocket 4 of the HLA-DR(alpha,beta 1*0401) molecule is a major determinant of T cells recognition of peptide

    PubMed Central

    1995-01-01

    To investigate the functional roles of individual HLA-DR residues in T cell recognition, transfectants expressing wild-type or mutant DR(alpha,beta 1*0401) molecules with single amino acid substitutions at 14 polymorphic positions of the DR beta 1*0401 chain or 19 positions of the DR alpha chain were used as antigen-presenting cells for five T cell clones specific for the influenza hemagglutinin peptide, HA307-19. Of the six polymorphic positions in the DR beta floor that were examined, mutations at only two positions eliminated T cell recognition: positions 13 (four clones) and 28 (one clone). In contrast, individual mutations at DR beta positions 70, 71, 78, and 86 on the alpha helix eliminated recognition by each of the clones, and mutations at positions 74 and 67 eliminated recognition by four and two clones, respectively. Most of the DR alpha mutations had minimal or no effect on most of the clones, although one clone was very sensitive to changes in the DR alpha chain, with loss of recognition in response to 10 mutants. Mutants that abrogated recognition by all of the clones were assessed for peptide binding, and only the beta 86 mutation drastically decreased peptide binding. Single amino acid substitutions at polymorphic positions in the central part of the DR beta alpha helix disrupted T cell recognition much more frequently than substitutions in the floor, suggesting that DR beta residues on the alpha helix make relatively greater contributions than those in the floor to the ability of the DR(alpha,beta 1*0401) molecule to present HA307-19. The data indicate that DR beta residues 13, 70, 71, 74, and 78, which are located in pocket 4 of the peptide binding site in the crystal structure of the DR1 molecule, exert a major and disproportionate influence on the outcome of T cell recognition, compared with other polymorphic residues. PMID:7869051

  17. The effect of erythrocyte antigen structure on requirement for T cells*

    PubMed Central

    Byrd, W.; Feldmann, Marc; Palmer, J.

    1974-01-01

    The induction in mice of a humoral immune response to intact sheep erythrocytes, both in vivo and in vitro, requires participation of thymus-derived (T) lymphocytes. In an in vitro system, spleen cells from both neonatally thymectomized and adult thymectomized irradiated bone marrow protected mice were successfully immunized, using washed sonicated sheep erythrocyte membrane fragments as antigen. This obviation of the requirement of T lymphocytes in the immune response, coupled with previous work on macrophage independence, indicates that sonicated membrane fragments were capable of directly immunizing bone marrow-derived (B) lymphocytes in vitro. These results further confirm the signal importance of antigenic structure in determining the cellular requirements for an immunological response; whereas antigens of particulate or monomeric form require the presence of both T cells and macrophages, polymeric antigens of intermediate size such as polymerized flagellin and sonicated sheep erythrocyte membranes require neither of these accessory cells. The results caution against the use of erythrocytes as models of thymus-dependent antigens. The data further suggest that reports of late antibody responses of relatively normal magnitude in thymectomized animals given larger doses of heterologous erythrocytes may have been due to direct immunization of B lymphocytes by degraded erythrocyte antigen. PMID:4138234

  18. Development of an algorithm for production of inactivated arbovirus antigens in cell culture

    PubMed Central

    Goodman, C.H.; Russell, B.J.; Velez, J.O.; Laven, J.J.; Nicholson, W.L; Bagarozzi, D.A.; Moon, J.L.; Bedi, K.; Johnson, B.W.

    2015-01-01

    Arboviruses are medically important pathogens that cause human disease ranging from a mild fever to encephalitis. Laboratory diagnosis is essential to differentiate arbovirus infections from other pathogens with similar clinical manifestations. The Arboviral Diseases Branch (ADB) reference laboratory at the CDC Division of Vector-Borne Diseases (DVBD) produces reference antigens used in serological assays such as the virus-specific immunoglobulin M antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA). Antigen production in cell culture has largely replaced the use of suckling mice; however, the methods are not directly transferable. The development of a cell culture antigen production algorithm for nine arboviruses from the three main arbovirus families, Flaviviridae, Togaviridae, and Bunyaviridae, is described here. Virus cell culture growth and harvest conditions were optimized, inactivation methods were evaluated, and concentration procedures were compared for each virus. Antigen performance was evaluated by the MAC-ELISA at each step of the procedure. The antigen production algorithm is a framework for standardization of methodology and quality control; however, a single antigen production protocol was not applicable to all arboviruses and needed to be optimized for each virus. PMID:25102428

  19. Development of an algorithm for production of inactivated arbovirus antigens in cell culture.

    PubMed

    Goodman, C H; Russell, B J; Velez, J O; Laven, J J; Nicholson, W L; Bagarozzi, D A; Moon, J L; Bedi, K; Johnson, B W

    2014-11-01

    Arboviruses are medically important pathogens that cause human disease ranging from a mild fever to encephalitis. Laboratory diagnosis is essential to differentiate arbovirus infections from other pathogens with similar clinical manifestations. The Arboviral Diseases Branch (ADB) reference laboratory at the CDC Division of Vector-Borne Diseases (DVBD) produces reference antigens used in serological assays such as the virus-specific immunoglobulin M antibody-capture enzyme-linked immunosorbent assay (MAC-ELISA). Antigen production in cell culture has largely replaced the use of suckling mice; however, the methods are not directly transferable. The development of a cell culture antigen production algorithm for nine arboviruses from the three main arbovirus families, Flaviviridae, Togaviridae, and Bunyaviridae, is described here. Virus cell culture growth and harvest conditions were optimized, inactivation methods were evaluated, and concentration procedures were compared for each virus. Antigen performance was evaluated by the MAC-ELISA at each step of the procedure. The antigen production algorithm is a framework for standardization of methodology and quality control; however, a single antigen production protocol was not applicable to all arboviruses and needed to be optimized for each virus.

  20. Improved poliovirus D-antigen yields by application of different Vero cell cultivation methods.

    PubMed

    Thomassen, Yvonne E; Rubingh, Olaf; Wijffels, René H; van der Pol, Leo A; Bakker, Wilfried A M

    2014-05-19

    Vero cells were grown adherent to microcarriers (Cytodex 1; 3 g L(-1)) using animal component free media in stirred-tank type bioreactors. Different strategies for media refreshment, daily media replacement (semi-batch), continuous media replacement (perfusion) and recirculation of media, were compared with batch cultivation. Cell densities increased using a feed strategy from 1×10(6) cells mL(-1) during batch cultivation to 1.8, 2.7 and 5.0×10(6) cells mL(-1) during semi-batch, perfusion and recirculation, respectively. The effects of these different cell culture strategies on subsequent poliovirus production were investigated. Increased cell densities allowed up to 3 times higher D-antigen levels when compared with that obtained from batch-wise Vero cell culture. However, the cell specific D-antigen production was lower when cells were infected at higher cell densities. This cell density effect is in good agreement with observations for different cell lines and virus types. From the evaluated alternative culture methods, application of a semi-batch mode of operations allowed the highest cell specific D-antigen production. The increased product yields that can easily be reached using these higher cell density cultivation methods, showed the possibility for better use of bioreactor capacity for the manufacturing of polio vaccines to ultimately reduce vaccine cost per dose. Further, the use of animal-component-free cell- and virus culture media shows opportunities for modernization of human viral vaccine manufacturing.

  1. A sharp T-cell antigen receptor signaling threshold for T-cell proliferation

    PubMed Central

    Au-Yeung, Byron B.; Zikherman, Julie; Mueller, James L.; Ashouri, Judith F.; Matloubian, Mehrdad; Cheng, Debra A.; Chen, Yiling; Shokat, Kevan M.; Weiss, Arthur

    2014-01-01

    T-cell antigen receptor (TCR) signaling is essential for activation, proliferation, and effector function of T cells. Modulation of both intensity and duration of TCR signaling can regulate these events. However, it remains unclear how individual T cells integrate such signals over time to make critical cell-fate decisions. We have previously developed an engineered mutant allele of the critical T-cell kinase zeta-chain-associated protein kinase 70 kDa (Zap70) that is catalytically inhibited by a small molecule inhibitor, thereby blocking TCR signaling specifically and efficiently. We have also characterized a fluorescent reporter Nur77–eGFP transgenic mouse line in which T cells up-regulate GFP uniquely in response to TCR stimulation. The combination of these technologies unmasked a sharp TCR signaling threshold for commitment to cell division both in vitro and in vivo. Further, we demonstrate that this threshold is independent of both the magnitude of the TCR stimulus and Interleukin 2. Similarly, we identify a temporal threshold of TCR signaling that is required for commitment to proliferation, after which T cells are able to proliferate in a Zap70 kinase-independent manner. Taken together, our studies reveal a sharp threshold for the magnitude and duration of TCR signaling required for commitment of T cells to proliferation. These results have important implications for understanding T-cell responses to infection and optimizing strategies for immunomodulatory drug delivery. PMID:25136127

  2. Antigen-presenting cells in human cutaneous leishmaniasis due to Leishmania major.

    PubMed Central

    ElHassan, A M; Gaafar, A; Theander, T G

    1995-01-01

    In this study biopsies from skin lesions and draining lymph nodes of patients suffering from cutaneous leishmaniasis caused by Leishmania major were examined by immunohistochemistry, and by light and electron microscopy to identify the types of antigen-presenting cells (APC) and their location. APC, identified morphologically and by their expression of specific cell markers, included Langerhans cells, macrophages, follicular dendritic cells, and interdigitating reticulum cells of the paracortex of lymph nodes. These cells expressed MHC class II antigens and contained Leishmania antigen. Since some keratinocytes and endothelial cells also showed these characteristics, they may also act as APC. By examining tissue samples from skin lesions and draining lymph nodes it was possible to follow the probable route of trafficking of various inflammatory cells between the skin lesion and lymph nodes. Leishmania antigen containing Langerhans cells were found in the epidermis, dermis and the regional lymph nodes. We believe these cells translocate from the epidermis to the dermis, where they take up antigen and migrate to the paracortex of the regional lymph nodes. There they are intimately associated with cells of the paracortex, and could be involved in the generation of Leishmania-specific T memory cells. LFA-1-positive T cells of the CD45RO phenotype were found in the skin lesion. Venular endothelium in the skin lesions expressed intercellular adhesion molecule-1 (ICAM-1), which is the ligand for LFA-1. The migration of lymphocytes from the vascular lumen to the site of inflammation is possibly a result of the interaction of these two adhesion molecules. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:7882568

  3. DDX3Y encodes a class I MHC–restricted H-Y antigen that is expressed in leukemic stem cells

    PubMed Central

    Rosinski, Kellie V.; Fujii, Nobuharu; Mito, Jeffrey K.; Koo, Kevin K. W.; Xuereb, Suzanne M.; Sala-Torra, Olga; Gibbs, James S.; Radich, Jerald P.; Akatsuka, Yoshiki; Van den Eynde, Benoît J.; Riddell, Stanley R.

    2008-01-01

    The Y chromosome encodes male-specific minor histocompatibility (H-Y) antigens that stimulate T- and B-lymphocyte responses after sex-mismatched allogeneic hematopoietic cell transplantation (HCT). A CD8+ cytotoxic T lymphocyte (CTL) clone that recognizes a novel HLA-B*2705–restricted H-Y antigen encoded by the DDX3Y gene was isolated from a male who had received a hematopoietic cell graft from his human leukocyte antigen (HLA)–identical sister. The antigenic peptide is a decamer that differs from the homologous DDX3X-encoded peptide at 4 positions. Expression of DDX3Y and of the H-Y epitope that it encodes was examined by quantitative polymerase chain reaction (PCR) and by CTL recognition assays. Expression of DDX3Y is detected in all myeloid and lymphoid leukemic cells that carry an intact Y chromosome. Moreover, the DDX3Y-encoded H-Y epitope is presented on the surface of both myeloid and lymphoid leukemic cells from male HLA-B*2705+ patients. DDX3Y-specific CTLs prevent engraftment of human acute leukemia in nonobese diabetic/severe combined immune deficient mice, demonstrating that the DDX3Y-encoded H-Y antigen is also expressed in leukemic stem cells. These results demonstrate that CD8+ T-cell responses against DDX3Y have the potential to contribute to graft-versus-leukemia (GVL) activity after female into male allogeneic HCT. This study is registered at http://clinicaltrials.gov as NCT00107354. PMID:18299450

  4. Cationic liposomes promote antigen cross-presentation in dendritic cells by alkalizing the lysosomal pH and limiting the degradation of antigens

    PubMed Central

    Gao, Jie; Ochyl, Lukasz J; Yang, Ellen; Moon, James J

    2017-01-01

    Cationic liposomes (CLs) have been widely examined as vaccine delivery nanoparticles since they can form complexes with biomacromolecules, promote delivery of antigens and adjuvant molecules to antigen-presenting cells (APCs), and mediate cellular uptake of vaccine components. CLs are also known to trigger antigen cross-presentation – the process by which APCs internalize extracellular protein antigens, degrade them into minimal CD8+ T-cell epitopes, and present them in the context of major histocompatibility complex-I (MHC-I). However, the precise mechanisms behind CL-mediated induction of cross-presentation and cross-priming of CD8+ T-cells remain to be elucidated. In this study, we have developed two distinct CL systems and examined their impact on the lysosomal pH in dendritic cells (DCs), antigen degradation, and presentation of peptide:MHC-I complexes to antigen-specific CD8+ T-cells. To achieve this, we have used 3β-[N-(N′,N′-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as the prototypical components of CLs with tertiary amine groups and compared the effect of CLs and anionic liposomes on lysosomal pH, antigen degradation, and cross-presentation by DCs. Our results showed that CLs, but not anionic liposomes, elevated the lysosomal pH in DCs and reduced antigen degradation, thereby promoting cross-presentation and cross-priming of CD8+ T-cell responses. These studies shed new light on CL-mediated cross-presentation and suggest that intracellular fate of vaccine components and subsequent immunological responses can be controlled by rational design of nanomaterials. PMID:28243087

  5. Cationic liposomes promote antigen cross-presentation in dendritic cells by alkalizing the lysosomal pH and limiting the degradation of antigens.

    PubMed

    Gao, Jie; Ochyl, Lukasz J; Yang, Ellen; Moon, James J

    2017-01-01

    Cationic liposomes (CLs) have been widely examined as vaccine delivery nanoparticles since they can form complexes with biomacromolecules, promote delivery of antigens and adjuvant molecules to antigen-presenting cells (APCs), and mediate cellular uptake of vaccine components. CLs are also known to trigger antigen cross-presentation - the process by which APCs internalize extracellular protein antigens, degrade them into minimal CD8(+) T-cell epitopes, and present them in the context of major histocompatibility complex-I (MHC-I). However, the precise mechanisms behind CL-mediated induction of cross-presentation and cross-priming of CD8(+) T-cells remain to be elucidated. In this study, we have developed two distinct CL systems and examined their impact on the lysosomal pH in dendritic cells (DCs), antigen degradation, and presentation of peptide:MHC-I complexes to antigen-specific CD8(+) T-cells. To achieve this, we have used 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as the prototypical components of CLs with tertiary amine groups and compared the effect of CLs and anionic liposomes on lysosomal pH, antigen degradation, and cross-presentation by DCs. Our results showed that CLs, but not anionic liposomes, elevated the lysosomal pH in DCs and reduced antigen degradation, thereby promoting cross-presentation and cross-priming of CD8(+) T-cell responses. These studies shed new light on CL-mediated cross-presentation and suggest that intracellular fate of vaccine components and subsequent immunological responses can be controlled by rational design of nanomaterials.

  6. Development of a T cell receptor targeting an HLA-A*0201 restricted epitope from the cancer-testis antigen SSX2 for adoptive immunotherapy of cancer.

    PubMed

    Abate-Daga, Daniel; Speiser, Daniel E; Chinnasamy, Nachimuthu; Zheng, Zhili; Xu, Hui; Feldman, Steven A; Rosenberg, Steven A; Morgan, Richard A

    2014-01-01

    The clinical success of adoptive immunotherapy of cancer relies on the selection of target antigens that are highly expressed in tumor cells but absent in essential normal tissues. A group of genes that encode the cancer/testis or cancer germline antigens have been proposed as ideal targets for immunotherapy due to their high expression in multiple cancer types and their restricted expression in immunoprivileged normal tissues. In the present work we report the isolation and characterization of human T cell receptors (TCRs) with specificity for synovial sarcoma X breakpoint 2 (SSX2), a cancer/testis antigen expressed in melanoma, prostate cancer, lymphoma, multiple myeloma and pancreatic cancer, among other tumors. We isolated seven HLA-A2 restricted T cell receptors from natural T cell clones derived from tumor-infiltrated lymph nodes of two SSX2-seropositive melanoma patients, and selected four TCRs for cloning into retroviral vectors. Peripheral blood lymphocytes (PBL) transduced with three of four SSX2 TCRs showed SSX241-49 (KASEKIFYV) peptide specific reactivity, tumor cell recognition and tetramer binding. One of these, TCR-5, exhibited tetramer binding in both CD4 and CD8 cells and was selected for further studies. Antigen-specific and HLA-A*0201-restricted interferon-γ release, cell lysis and lymphocyte proliferation was observed following culture of TCR engineered human PBL with relevant tumor cell lines. Codon optimization was found to increase TCR-5 expression in transduced T cells, and this construct has been selected for development of clinical grade viral vector producing cells. The tumor-specific pattern of expression of SSX2, along with the potent and selective activity of TCR-5, makes this TCR an attractive candidate for potential TCR gene therapy to treat multiple cancer histologies.

  7. Detection of Avian Antigen-Specific T Cells Induced by Viral Vaccines.

    PubMed

    Dalgaard, Tina Sørensen; Norup, Liselotte Rothmann; Juul-Madsen, Helle Risdahl

    2016-01-01

    Live attenuated viral vaccines are widely used in commercial poultry production, but the development of new effective inactivated/subunit vaccines is needed. Studies of avian antigen-specific T cells are primarily based on analyses ex vivo after activating the cells with recall antigen. There is a particular interest in developing robust high-throughput assays as chicken vaccine trials usually comprise many individuals. In many respects, the avian immune system differs from the mammalian, and T cell assessment protocols must be adjusted accordingly to account for, e.g., differences in leukocyte subsets.The carboxyfluorescein succinimidyl ester (CFSE) method described in this chapter has been adapted to chicken cells. In this test, cells of interest are stained with CFSE. The succinimidyl ester group covalently binds to cellular amines forming fluorescent conjugates that are retained in the cells even throughout division. This leads to daughter cells containing half the fluorescence of their parents. When lymphocytes are loaded with CFSE prior to ex vivo stimulation with specific antigen, the measurement of serial halving of its fluorescence by flow cytometry identifies the cells responding to the stimulation. This method has been successfully applied to studies of chicken antigen-specific T cells.

  8. Pros and Cons of Antigen-Presenting Cell Targeted Tumor Vaccines.

    PubMed

    Goyvaerts, Cleo; Breckpot, Karine

    2015-01-01

    In therapeutic antitumor vaccination, dendritic cells play the leading role since they decide if, how, when, and where a potent antitumor immune response will take place. Since the disentanglement of the complexity and merit of different antigen-presenting cell subtypes, antitumor immunotherapeutic research started to investigate the potential benefit of targeting these subtypes in situ. This review will discuss which antigen-presenting cell subtypes are at play and how they have been targeted and finally question the true meaning of targeting antitumor-based vaccines.

  9. Pros and Cons of Antigen-Presenting Cell Targeted Tumor Vaccines

    PubMed Central

    Goyvaerts, Cleo; Breckpot, Karine

    2015-01-01

    In therapeutic antitumor vaccination, dendritic cells play the leading role since they decide if, how, when, and where a potent antitumor immune response will take place. Since the disentanglement of the complexity and merit of different antigen-presenting cell subtypes, antitumor immunotherapeutic research started to investigate the potential benefit of targeting these subtypes in situ. This review will discuss which antigen-presenting cell subtypes are at play and how they have been targeted and finally question the true meaning of targeting antitumor-based vaccines. PMID:26583156

  10. Exogenous fms-like tyrosine kinase 3 ligand overrides brain immune privilege and facilitates recognition of a neo-antigen without causing autoimmune neuropathology

    PubMed Central

    Larocque, Daniel; Sanderson, Nicholas S. R.; Bergeron, Josée; Curtin, James F.; Girton, Joe; Wibowo, Mia; Bondale, Niyati; Kroeger, Kurt M.; Yang, Jieping; Lacayo, Liliana M.; Reyes, Kevin C.; Farrokhi, Catherine; Pechnick, Robert N.; Castro, Maria G.; Lowenstein, Pedro R.

    2010-01-01

    Soluble antigens diffuse out of the brain and can thus stimulate a systemic immune response, whereas particulate antigens (from infectious agents or tumor cells) remain within brain tissue, thus failing to stimulate a systemic immune response. Immune privilege describes how the immune system responds to particulate antigens localized selectively within the brain parenchyma. We believe this immune privilege is caused by the absence of antigen presenting dendritic cells from the brain. We tested the prediction that expression of fms-like tyrosine kinase ligand 3 (Flt3L) in the brain will recruit dendritic cells and induce a systemic immune response against exogenous influenza hemagglutinin in BALB/c mice. Coexpression of Flt3L with HA in the brain parenchyma induced a robust systemic anti-HA immune response, and a small response against myelin basic protein and proteolipid protein epitopes. Depletion of CD4+CD25+ regulatory T cells (Tregs) enhanced both responses. To investigate the autoimmune impact of these immune responses, we characterized the neuropathological and behavioral consequences of intraparenchymal injections of Flt3L and HA in BALB/c and C57BL/6 mice. T cell infiltration in the forebrain was time and strain dependent, and increased in animals treated with Flt3L and depleted of Tregs; however, we failed to detect widespread defects in myelination throughout the forebrain or spinal cord. Results of behavioral tests were all normal. These results demonstrate that Flt3L overcomes the brain's immune privilege, and supports the clinical development of Flt3L as an adjuvant to stimulate clinically effective immune responses against brain neo-antigens, for example, those associated with brain tumors. PMID:20660723

  11. Inhibition of immune opsonin-independent phagocytosis by antibody to a pulmonary macrophage cell surface antigen

    SciTech Connect

    Parod, R.J.; Godleski, J.J.; Brain J.D.

    1986-03-15

    Unlike other hamster phagoycytes, hamster pulmonary macrophages (PM) avidly ingest albumin-coated latex particles in the absence of serum. They also possess a highly specific cell surface antigen. To evaluate the relationship between these two characteristics, PM were incubated with mouse monoclonal antibody directed against the PM antigen. After unbound antibody was removed, the amount of bound antibody and the phagocytic capability of PM were measured by flow cytometry and fluorescence microscopy. Maximum antibody binding produced a 25% inhibition of ingestion. Particle attachment was not affected. This effect was antigen specific, since neither a nonspecific mouse myeloma protein of the same subclass nor a mouse antibody that bound to another hamster surface antigen had any effect on binding or ingestion. If antigen-specific F(ab')/sub 2/ fragments were introduced both before and during the period of phagocytosis, the inhibition of particle ingestion approached 100%. Particle binding increased at low F(ab')/sub 2/ concentrations but declined at higher concentrations. Because calcium may play a role in the ingestion process, the effect of antibody on /sup 45/Ca uptake was evaluated. It was observed that antigen-specific F(ab')/sub 2/ fragments stimulated /sup 45/Ca uptake, whereas control antibodies did not. These results suggest that the antigen reacting with the anti-hamster PM monoclonal antibody is involved in immune opsonin-independent phagocytosis and that calcium participates in this phagocytic process.

  12. Merging Of Different Segmentation Techniques For Cell Image Recognition

    NASA Astrophysics Data System (ADS)

    Serpico, Sebastiano B.; Vernazza, Gianni L.; Dellepiane, Silvana G.

    1989-03-01

    In this paper, we present a knowledge-based system for segmentation and interpretation of 2-D images, specialized for neural cells recognition, and based on both region and edge information. Cell images are obtained by acoustic microscopy, and are characterized by nonuniform background, and low contrast (expecially for dendrite contours). Neural cells have compact shapes, while dendrites are thin and elongated. Consequently, for cell bodies, region information has proved basic, while edges are used to refine their contours, or to solve incorrect situations. Edges are of major importance for dendrite location, since their shape creates some difficulties to region-based segmentation. Elementary regions are provided by region-growing; edges are obtained by detecting zero-crossings of the second derivative of grey-level behaviour. A symbolic representation of the above primitives is stored inside a Global Database (GDB), and contains information about properties and relations of regions and edges. Procedural knowledge, represented as production rules, and organized at hierarchical levels, is applied by means of a rule interpreter, according to the current problem status stored inside the GDB. As starting point, a region preclassification is performed on the basis of a priori knowledge about neuron and dendrite features; a refinement is subsequently obtained by employing alternatively edges and regions again. The system output is a symbolic map which shows background, cell bodies and dendrites in different colours. Experimental results are presented and discussed.

  13. Tetramer-guided epitope mapping: rapid identification and characterization of immunodominant CD4+ T cell epitopes from complex antigens.

    PubMed

    Novak, E J; Liu, A W; Gebe, J A; Falk, B A; Nepom, G T; Koelle, D M; Kwok, W W

    2001-06-01

    T cell responses to Ags involve recognition of selected peptide epitopes contained within the antigenic protein. In this report, we describe a new approach for direct identification of CD4+ T cell epitopes of complex Ags that uses human class II tetramers to identify reactive cells. With a panel of 60 overlapping peptides covering the entire sequence of the VP16 protein, a major Ag for HSV-2, we generated a panel of class II MHC tetramers loaded with peptide pools that were used to stain peripheral lymphocytes of an HSV-2 infected individual. With this approach, we identified four new DRA1*0101/DRB1*0401- and two DRA1*0101/DRB1*0404-restricted, VP16-specific epitopes. By using tetramers to sort individual cells, we easily obtained a large number of clones specific to these epitopes. Although DRA1*0101/DRB1*0401 and DRA1*0101/DRB1*0404 are structurally very similar, nonoverlapping VP16 epitopes were identified, illustrating high selectivity of individual allele polymorphisms within common MHC variants. This rapid approach to detecting CD4+ T cell epitopes from complex Ags can be applied to any known Ag that gives a T cell response.

  14. Apical membrane antigen 1 mediates apicomplexan parasite attachment but is dispensable for host cell invasion

    PubMed Central

    Bargieri, Daniel Y.; Andenmatten, Nicole; Lagal, Vanessa; Thiberge, Sabine; Whitelaw, Jamie A.; Tardieux, Isabelle; Meissner, Markus; Ménard, Robert

    2013-01-01

    Apicomplexan parasites invade host cells by forming a ring-like junction with the cell surface and actively sliding through the junction inside an intracellular vacuole. Apical membrane antigen 1 is conserved in apicomplexans and a long-standing malaria vaccine candidate. It is considered to have multiple important roles during host cell penetration, primarily in structuring the junction by interacting with the rhoptry neck 2 protein and transducing the force generated by the parasite motor during internalization. Here, we generate Plasmodium sporozoites and merozoites and Toxoplasma tachyzoites lacking apical membrane antigen 1, and find that the latter two are impaired in host cell attachment but the three display normal host cell penetration through the junction. Therefore, apical membrane antigen 1, rather than an essential invasin, is a dispensable adhesin of apicomplexan zoites. These genetic data have implications on the use of apical membrane antigen 1 or the apical membrane antigen 1–rhoptry neck 2 interaction as targets of intervention strategies against malaria or other diseases caused by apicomplexans. PMID:24108241

  15. In vivo targeting of antigens to maturing dendritic cells via the DEC-205 receptor improves T cell vaccination.

    PubMed

    Bonifaz, Laura C; Bonnyay, David P; Charalambous, Anna; Darguste, Dara I; Fujii, Shin-Ichiro; Soares, Helena; Brimnes, Marie K; Moltedo, Bruno; Moran, Thomas M; Steinman, Ralph M

    2004-03-15

    The prevention and treatment of prevalent infectious diseases and tumors should benefit from improvements in the induction of antigen-specific T cell immunity. To assess the potential of antigen targeting to dendritic cells to improve immunity, we incorporated ovalbumin protein into a monoclonal antibody to the DEC-205 receptor, an endocytic receptor that is abundant on these cells in lymphoid tissues. Simultaneously, we injected agonistic alpha-CD40 antibody to mature the dendritic cells. We found that a single low dose of antibody-conjugated ovalbumin initiated immunity from the naive CD4+ and CD8+ T cell repertoire. Unexpectedly, the alphaDEC-205 antigen conjugates, given s.c., targeted to dendritic cells systemically and for long periods, and ovalbumin peptide was presented on MHC class I for 2 weeks. This was associated with stronger CD8+ T cell-mediated immunity relative to other forms of antigen delivery, even when the latter was given at a thousand times higher doses. In parallel, the mice showed enhanced resistance to an established rapidly growing tumor and to viral infection at a mucosal site. By better harnessing the immunizing functions of maturing dendritic cells, antibody-mediated antigen targeting via the DEC-205 receptor increases the efficiency of vaccination for T cell immunity, including systemic and mucosal resistance in disease models.

  16. A Single Subset of Dendritic Cells Controls the Cytokine Bias of Natural Killer T Cell Responses to Diverse Glycolipid Antigens

    PubMed Central

    Arora, Pooja; Baena, Andres; Yu, Karl O.A.; Saini, Neeraj K.; Kharkwal, Shalu S.; Goldberg, Michael F.; Kunnath-Velayudhan, Shajo; Carreño, Leandro J.; Venkataswamy, Manjunatha M.; Kim, John; Lazar-Molnar, Eszter; Lauvau, Gregoire; Chang, Young-tae; Liu, Zheng; Bittman, Robert; Al-Shamkhani, Aymen; Cox, Liam R.; Jervis, Peter J.; Veerapen, Natacha; Besra, Gurdyal S.; Porcelli, Steven A.

    2014-01-01

    Summary Many hematopoietic cell types express CD1d and are capable of presenting glycolipid antigens to invariant natural killer T cells (iNKT cells). However, the question of which cells are the principal presenters of glycolipid antigens in vivo remains controversial, and it has been suggested that this might vary depending on the structure of a particular glycolipid antigen. Here we have shown that a single type of cell, the CD8α+ DEC-205+ dendritic cell, was mainly responsible for capturing and presenting a variety of different glycolipid antigens, including multiple forms of α-galactosylceramide that stimulate widely divergent cytokine responses. After glycolipid presentation, these dendritic cells rapidly altered their expression of various costimulatory and coinhibitory molecules in a manner that was dependent on the structure of the antigen. These findings show flexibility in the outcome of two-way communication between CD8α+ dendritic cells and iNKT cells, providing a mechanism for biasing toward either proinflammatory or anti-inflammatory responses. PMID:24412610

  17. A single subset of dendritic cells controls the cytokine bias of natural killer T cell responses to diverse glycolipid antigens.

    PubMed

    Arora, Pooja; Baena, Andres; Yu, Karl O A; Saini, Neeraj K; Kharkwal, Shalu S; Goldberg, Michael F; Kunnath-Velayudhan, Shajo; Carreño, Leandro J; Venkataswamy, Manjunatha M; Kim, John; Lazar-Molnar, Eszter; Lauvau, Gregoire; Chang, Young-tae; Liu, Zheng; Bittman, Robert; Al-Shamkhani, Aymen; Cox, Liam R; Jervis, Peter J; Veerapen, Natacha; Besra, Gurdyal S; Porcelli, Steven A

    2014-01-16

    Many hematopoietic cell types express CD1d and are capable of presenting glycolipid antigens to invariant natural killer T cells (iNKT cells). However, the question of which cells are the principal presenters of glycolipid antigens in vivo remains controversial, and it has been suggested that this might vary depending on the structure of a particular glycolipid antigen. Here we have shown that a single type of cell, the CD8α(+) DEC-205(+) dendritic cell, was mainly responsible for capturing and presenting a variety of different glycolipid antigens, including multiple forms of α-galactosylceramide that stimulate widely divergent cytokine responses. After glycolipid presentation, these dendritic cells rapidly altered their expression of various costimulatory and coinhibitory molecules in a manner that was dependent on the structure of the antigen. These f