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Sample records for antibody variants produced

  1. Discovery and characterization of antibody variants using mass spectrometry-based comparative analysis for biosimilar candidates of monoclonal antibody drugs.

    PubMed

    Li, Wenhua; Yang, Bin; Zhou, Dongmei; Xu, Jun; Ke, Zhi; Suen, Wen-Chen

    2016-07-01

    Liquid chromatography mass spectrometry (LC-MS) is the most commonly used technique for the characterization of antibody variants. MAb-X and mAb-Y are two approved IgG1 subtype monoclonal antibody drugs recombinantly produced in Chinese hamster ovary (CHO) cells. We report here that two unexpected and rare antibody variants have been discovered during cell culture process development of biosimilars for these two approved drugs through intact mass analysis. We then used comprehensive mass spectrometry-based comparative analysis including reduced light, heavy chains, and domain-specific mass as well as peptide mapping analysis to fully characterize the observed antibody variants. The "middle-up" mass comparative analysis demonstrated that the antibody variant from mAb-X biosimilar candidate was caused by mass variation of antibody crystalline fragment (Fc), whereas a different variant with mass variation in antibody antigen-binding fragment (Fab) from mAb-Y biosimilar candidate was identified. Endoproteinase Lys-C digested peptide mapping and tandem mass spectrometry analysis further revealed that a leucine to glutamine change in N-terminal 402 site of heavy chain was responsible for the generation of mAb-X antibody variant. Lys-C and trypsin coupled non-reduced and reduced peptide mapping comparative analysis showed that the formation of the light-heavy interchain trisulfide bond resulted in the mAb-Y antibody variant. These two cases confirmed that mass spectrometry-based comparative analysis plays a critical role for the characterization of monoclonal antibody variants, and biosimilar developers should start with a comprehensive structural assessment and comparative analysis to decrease the risk of the process development for biosimilars. PMID:27214604

  2. Exceptional Antibodies Produced by Successive Immunizations.

    PubMed

    Gearhart, Patricia J; Castiblanco, Diana P; Russell Knode, Lisa M

    2015-12-01

    Antibodies stand between us and pathogens. Viruses mutate quickly to avoid detection, and antibodies mutate at similar rates to hunt them down. This death spiral is fueled by specialized proteins and error-prone polymerases that change DNA sequences. Here, we explore how B lymphocytes stay in the race by expressing activation-induced deaminase, which unleashes a tsunami of mutations in the immunoglobulin loci. This produces random DNA substitutions, followed by selection for the highest affinity antibodies. We may be able to manipulate the process to produce better antibodies by expanding the repertoire of specific B cells through successive vaccinations. PMID:26641938

  3. Glycosylation of plant produced human antibodies.

    PubMed

    Kallolimath, Somanath; Steinkellner, Herta

    2015-12-23

    Human immunoglobulins circulate as highly heterogeneously glycosylated mixture of otherwise homogeneous protein backbones. A series of studies, mainly on IgG, have unequivocally proven that antibodies modulate their effector function through sugars present in the Fc domain. However, our limited technology in producing complex proteins such as antibodies, with defined glycan structures hamper in depths studies. This review introduces a plant based expression platform enabling engineering of antibody glycans. The procedure is based on the simultaneous delivery of appropriate constructs, carrying cDNAs of target proteins (e.g. heavy and light chain of antibodies) in combination with human glycosylation enzymes into plant leaves. Harvesting of recombinant proteins one week post construct delivery allows high speed and flexibility. Major achievements include the production of functional active slialylated pentameric IgMs in tobacco leaves. The system provides a viable approach to the generation of antibodies with defined glycoforms on demand, contributing to studies on antibody glycans and the development of novel antibody based drugs. PMID:27472861

  4. Prion-Specific Antibodies Produced in Wild-Type Mice.

    PubMed

    Heegaard, Peter M H; Bergström, Ann-Louise; Andersen, Heidi Gertz; Cordes, Henriette

    2015-01-01

    Peptide-specific antibodies produced against synthetic peptides are of high value in probing protein structure and function, especially when working with challenging proteins, including not readily available, non-immunogenic, toxic, and/or pathogenic proteins. Here, we present a straightforward method for production of mouse monoclonal antibodies (MAbs) against peptides representing two sites of interest in the bovine prion protein (boPrP), the causative agent of bovine spongiform encephalopathy ("mad cow disease") and new variant Creutzfeldt-Jakob's disease (CJD) in humans, as well as a thorough characterization of their reactivity with a range of normal and pathogenic (misfolded) prion proteins. It is demonstrated that immunization of wild-type mice with ovalbumin-conjugated peptides formulated with Freund's adjuvant induces a good immune response, including high levels of specific anti-peptide antibodies, even against peptides very homologous to murine protein sequences. In general, using the strategies described here for selecting, synthesizing, and conjugating peptides and immunizing 4-5 mice with 2-3 different peptides, high-titered antibodies reacting with the target protein are routinely obtained with at least one of the peptides after three to four immunizations with incomplete Freund's adjuvant. PMID:26424281

  5. Production and characterization of a peptide-based monoclonal antibody against CD44 variant 6.

    PubMed

    Zarei, Saeed; Bayat, Ali Ahmad; Hadavi, Reza; Mahmoudi, Ahmad R; Tavangar, Banafsheh; Vojgani, Yasaman; Jeddi-Tehrani, Mahmood; Amirghofran, Zahra

    2015-02-01

    The gene that codes for the CD44 family members consists of 20 exons, nine of which encode the standard form of the molecule. The other exons can be inserted in various combinations into the membrane proximal region of the extracellular domain of the protein, giving rise to variant isoforms (CD44v). CD44 variants, especially the CD44v6, have been reported to regulate tumor invasion, progression, and metastasis of carcinomas. Producing a high affinity monoclonal antibody against human CD44v6 provides a powerful tool to monitor and trace CD44v6 function in different biological fluids. In this study, a synthetic peptide from CD44v6 was conjugated to keyhole limpet hemocyanin (KLH) and injected into BALB/c mice. Splenocytes from the immunized mice were fused with murine SP2/0 myeloma cells followed by selection of antibody producing hybridoma cells. After screening of hybridoma colonies by ELISA, high affinity antibodies were selected and purified by affinity chromatography. Western blot, immunocytochemistry, and flow cytometry experiments were used to characterize the antibodies. Six stable hybridoma cell lines, designated as 1H1, 1H2, 2A12, 2G11, 3H3, and 3H7, were obtained. Flow cytometry and immunocytochemistry results showed that the new monoclonal antibodies recognized CD44v6 on the cell surface. This novel panel of anti-CD44v6 antibodies has the potential for investigating the role of CD44v6 in cancer pathogenesis. PMID:25723282

  6. Production and Characterization of a Peptide-based Monoclonal Antibody Against CD44 Variant 6

    PubMed Central

    Zarei, Saeed; Bayat, Ali Ahmad; Hadavi, Reza; Mahmoudi, Ahmad R.; Tavangar, Banafsheh; Vojgani, Yasaman; Jeddi-Tehrani, Mahmood

    2015-01-01

    The gene that codes for the CD44 family members consists of 20 exons, nine of which encode the standard form of the molecule. The other exons can be inserted in various combinations into the membrane proximal region of the extracellular domain of the protein, giving rise to variant isoforms (CD44v). CD44 variants, especially the CD44v6, have been reported to regulate tumor invasion, progression, and metastasis of carcinomas. Producing a high affinity monoclonal antibody against human CD44v6 provides a powerful tool to monitor and trace CD44v6 function in different biological fluids. In this study, a synthetic peptide from CD44v6 was conjugated to keyhole limpet hemocyanin (KLH) and injected into BALB/c mice. Splenocytes from the immunized mice were fused with murine SP2/0 myeloma cells followed by selection of antibody producing hybridoma cells. After screening of hybridoma colonies by ELISA, high affinity antibodies were selected and purified by affinity chromatography. Western blot, immunocytochemistry, and flow cytometry experiments were used to characterize the antibodies. Six stable hybridoma cell lines, designated as 1H1, 1H2, 2A12, 2G11, 3H3, and 3H7, were obtained. Flow cytometry and immunocytochemistry results showed that the new monoclonal antibodies recognized CD44v6 on the cell surface. This novel panel of anti-CD44v6 antibodies has the potential for investigating the role of CD44v6 in cancer pathogenesis. PMID:25723282

  7. The cytokines effect on EBV-immortalized human B cells producing antisperm antibody.

    PubMed

    Fiszer, D; Niedbała, W; Fernandez, N; Kurpisz, M

    1992-01-01

    We have analyzed the antisperm antibody production of autoimmunized male subjects using Epstein-Barr virus (EBV) immortalization of B lymphocytes. We evaluated the influence of several in vitro culture variants applied prior to EBV infection on the frequence of antibody-producing cells and affinity of secreted antibodies. The following variants were applied: a) polyclonal antigenic stimulation of lymphocytes with PWM, b) PWM (pokeweed mitogen) + IL-2 + interferon gamma and c) PWM + IL-2 + interferon gamma + sperm antigenic extract. The variants where the cytokines were added did not increase the frequency of EBV-infected antibody-producing cells as comparing to EBV infection previously amplified by the use of polyclonal activator. Furthermore the cytokine activation either in combination with mitogen or in vitro secondary antigenic sensitization (prior to EBV transformation) did not seem to have beneficial effect on affinity of antibodies produced by EBV-infected cells in comparison to straight EBV infection. On the other hand, the attempt to promote an immunoglobulin secretion (IgM) by previously obtained human-human antisperm hybridomas by adding of IL-2 was quite successful. PMID:1338684

  8. Monoclonal antibodies produced by muscle after plasmid injection and electroporation.

    PubMed

    Tjelle, Torunn Elisabeth; Corthay, Alexandre; Lunde, Elin; Sandlie, Inger; Michaelsen, Terje E; Mathiesen, Iacob; Bogen, Bjarne

    2004-03-01

    Antibodies are useful for the treatment of a variety of diseases. We here demonstrate that mouse muscle produced monoclonal antibodies (mAb) after a single injection of immunoglobulin genes as plasmid DNA. In vivo electroporation of muscle greatly enhanced antibody production. For chimeric antibodies, levels of 50-200 ng mAb/ml serum were obtained but levels declined after 7-14 days due to an immune response against the xenogeneic parts of the antibody. By contrast, fully mouse antibodies persisted in serum for at least 7 months. mAb produced by the muscle had correct structure, specificity, and biological effector functions. The findings were extended to a larger animal, the sheep, in which mAb serum levels of 30-50 ng/ml were obtained. Sustained levels of serum mAb, induced by single injection of Ig genes and electroporation of muscle cells, may offer significant advantages in the treatment of human diseases. PMID:15006599

  9. Opsonization of Cryptococcus neoformans by a family of isotype-switch variant antibodies specific for the capsular polysaccharide.

    PubMed Central

    Schlageter, A M; Kozel, T R

    1990-01-01

    A family of immunoglobulin isotype-switch variants was isolated by sib selection from a murine hybridoma which produced an immunoglobulin G subclass 1 (IgG1) antibody specific for the capsular polysaccharide of Cryptococcus neoformans. Antibodies of the IgG1, IgG2a, and IgG2b isotypes had similar serotype specificity patterns in double immunodiffusion assays which used polysaccharides of the four cryptococcal serotypes as antigens. A quantitative difference in the ability of the isotypes to form a precipitate with the polysaccharide was observed in a double immunodiffusion assay and confirmed in a quantitative precipitin assay. The relative precipitating activity of the antibodies was IgG2a greater than IgG1 much greater than IgG2b. Analysis by enzyme-linked immunosorbent assay of the reactivity of the three isotypes with cryptococcal polysaccharide showed identical titers and slopes, suggesting that the variable region of the class-switch antibodies was unaltered. This system allowed us to examine the effect of the Fc portion of the antibody on opsonization of encapsulated cryptococci. Yeast cells were precoated with antibodies of each isotype and incubated with murine macrophages or cultured human monocytes. Antibodies of all three isotypes exhibited a dose-dependent opsonization for phagocytosis by both human and murine phagocytes. The relative opsonic activity of the antibodies was IgG2a greater than IgG1 greater than IgG2b. Images PMID:2187813

  10. Considerations in producing preferentially reduced half-antibody fragments.

    PubMed

    Makaraviciute, Asta; Jackson, Carolyn D; Millner, Paul A; Ramanaviciene, Almira

    2016-02-01

    Half-antibody fragments are a promising reagent for biosensing, drug-delivery and labeling applications, since exposure of the free thiol group in the Fc hinge region allows oriented reaction. Despite the structural variations among the molecules of different IgG subclasses and those obtained from different hosts, only generalized preferential antibody reduction protocols are currently available. Preferential reduction of polyclonal sheep anti-digoxin, rabbit anti-Escherichia coli and anti-myoglobin class IgG antibodies to half-antibody fragments has been investigated. A mild reductant 2-mercaptoethylamine (2-MEA) and a slightly stronger reductant tris(2-carboxyethyl)phosphine (TCEP) were used and the fragments obtained were quantitatively determined by SDS-PAGE analysis. It has been shown that the yields of half-antibody fragments could be increased by lowering the pH of the reduction mixtures. However, antibody susceptibility to the reductants varied. At pH4.5 the highest yield of sheep anti-digoxin IgG half-antibody fragments was obtained with 1M 2-MEA. Conversely, rabbit IgG half-antibody fragments could only be obtained with the stronger reductant TCEP. Preferential reduction of rabbit anti-myoglobin IgG antibodies was optimized and the highest half-antibody yield was obtained with 35 mM TCEP. Finally, it has been demonstrated that produced anti-myoglobin half-IgG fragments retained their binding activity. PMID:26779832

  11. Cellular cytotoxicity mediated by isotype-switch variants of a monoclonal antibody to human neuroblastoma.

    PubMed Central

    d'Uscio, C. H.; Jungi, T. W.; Blaser, K.

    1991-01-01

    The biological property of an antibody is determined by its antigen binding characteristics and its isotype-related effector functions. We have established monoclonal antibodies of different isotypes by stepwise selection and cloning of the hybridoma CE7. The original CE7 secretes an IgG1/kappa (CE7 gamma 1) antibody that recognises a 185 kD cell surface glycoprotein expressed on all human sympatho-adrenomedullary cells. Isotype-switch variants were isolated in the following sequence: from the original CE7 gamma 1, CE7 gamma 2b variants were isolated, and from a CE7 gamma 2b variant CE7 gamma 2a variants were isolated. The antibodies of three different isotype variant cell lines possess identical antigen binding characteristics, but display distinct effector functions as demonstrated by antibody dependent cell-mediated cytotoxicity (ADCC). ADCC was performed with the neuroblastoma line IMR-32 as the target cells, and different FcR gamma positive cells were either freshly isolated from human peripheral blood leukocytes or cultured for 6-10 days and tested as potential effector cells. Tumour lysis mediated by monocyte-derived macrophages depended on the presence of CE7 gamma 2a antibodies; antibodies from the CE7 hybridomas of gamma 2b and gamma 1 isotypes were virtually inactive in ADCC assay. Pre-exposure of macrophages to rIFN-gamma enhanced their ADCC activity, a result that is compatible with the notion that the high affinity Fc IgG receptor (FcR gamma I/CD64) is involved in the triggering of ADCC in macrophages. In contrast to macrophages, mononuclear cells, nonadherent cells and monocytes displayed considerable non-specific lytic activity, which was little influenced by the presence of antibody regardless of the isotype added. PMID:1911183

  12. Neutralizing monoclonal antibodies recognize antigenic variants among isolates of infectious hematopoietic necrosis virus

    USGS Publications Warehouse

    Winton, J.R.; Arakawa, C.N.; Lannan, C.N.; Fryer, J.L.

    1988-01-01

    eutralizing monoclonal antibodies were developed against strains of infectious hematopoietic necrosis virus (IHNV) from steelhead trout Salmo gairdneri in the Deschutes River of Oregon, chinook salmon Oncorhynchus tshawytscha in the Sacramento River of California, and rainbow trout Salmo gairdneri reared in the Hagerman Valley of Idaho, USA. These antibodies were tested for neutralization of 12 IHNV isolates obtained from salmonids in Japan, Alaska, Washington, Oregon, California, and Idaho. The antibodies recognized antigenic variants among the isolates and could be used to separate the viruses into 4 groups. The members of each group tended to be related by geographic area rather than by source host species, virulence, or date of isolation.

  13. Separation of Oxidized Variants of a Monoclonal Antibody by Anion-Exchange

    PubMed Central

    Teshima, Glen; Li, Ming-Xiang; Danishmand, Rahima; Obi, Chidi; To, Robert; Huang, Carol; Lahidji, Vafa; Freeberg, Joel; Thorner, Lauren; Tomic, Milan

    2010-01-01

    Monoclonal antibodies are subject to a variety of degradation mechanisms, therefore orthogonal techniques are required to demonstrate product quality. In this study, the three individual antibodies comprising a multi-antibody drug product, XOMA 3AB were evaluated by both cation-exchange (CEX) and anion-exchange chromatography (AEX). In contrast to CEX analysis which showed only a single, broad peak for the force-oxidized antibodies, AEX analysis of Ab-A (pI=7.6) revealed two more basic peaks. Ab-B (pI=6.7) bound but exhibited only a single major peak while Ab-C (pI=8.6) flowed through. Peptide mapping LC/MS analysis of the isolated Ab-A fractions demonstrated that the basic peaks resulted from oxidation in a complementary determining region (CDR). Differential scanning calorimetry (DSC) analysis of the oxidized Ab-A species showed a decrease in the Fab melting point for the oxidized species consistent with unfolding of the molecule. Greater/lesser surface exposure of ionic residues resulting from a conformational change provides a likely explanation for the dramatic shift in retention behavior for the Ab-A oxidized variants. Peptide mapping analysis of the Ab-B antibody showed, in contrast to Ab-A, no detectable CDR oxidation. Hence, the lack of separation of oxidized variants in Ab-B can be explained by the absence of CDR oxidation and the associated changes in secondary/tertiary structure which were observed for oxidized AbA. In summary, anion-exchange HPLC shows potential as an orthogonal analytical technique for assessing product quality of monoclonal antibody therapeutics. In the case of the XOMA 3AB drug product, two of the antibodies bound and one, Ab-A, exhibited separation of CDR oxidized variants. PMID:21145555

  14. Antibody

    MedlinePlus

    An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples ... microorganisms (bacteria, fungi, parasites, and viruses) and chemicals. Antibodies may be produced when the immune system mistakenly ...

  15. Characterization of alanine to valine sequence variants in the Fc region of nivolumab biosimilar produced in Chinese hamster ovary cells.

    PubMed

    Li, Yantao; Fu, Tuo; Liu, Tao; Guo, Huaizu; Guo, Qingcheng; Xu, Jin; Zhang, Dapeng; Qian, Weizhu; Dai, Jianxin; Li, Bohua; Guo, Yajun; Hou, Sheng; Wang, Hao

    2016-07-01

    Nivolumab is a therapeutic fully human IgG4 antibody to programmed death 1 (PD-1). In this study, a nivolumab biosimilar, which was produced in our laboratory, was analyzed and characterized. Sequence variants that contain undesired amino acid sequences may cause concern during biosimilar bioprocess development. We found that low levels of sequence variants were detected in the heavy chain of the nivolumab biosimilar by ultra performance liquid chromatography (UPLC) and tandem mass spectrometry. It was further identified with UPLC-MS/MS by IdeS or trypsin digestion. The sequence variant was confirmed through addition of synthetic mutant peptide. Subsequently, the mixing base signal of normal and mutant sequence was detected through DNA sequencing. The relative levels of mutant A424V in the Fc region of the heavy chain have been detected and demonstrated to be 12.25% and 13.54%, via base peak intensity (BPI) and UV chromatography of the tryptic peptide mapping, respectively. A424V variant was also quantified by real-time PCR (RT-PCR) at the DNA and RNA level, which was 19.2% and 16.8%, respectively. The relative content of the mutant was consistent at the DNA, RNA and protein level, indicating that the A424V mutation may have little influence at transcriptional or translational levels. These results demonstrate that orthogonal state-of-the-art techniques such as LC- UV- MS and RT-PCR should be implemented to characterize recombinant proteins and cell lines for development of biosimilars. Our study suggests that it is important to establish an integrated and effective analytical method to monitor and characterize sequence variants during antibody drug development, especially for antibody biosimilar products. PMID:27050807

  16. Monoclonal antibody-escape variant of dengue virus serotype 1: Genetic composition and envelope protein expression.

    PubMed

    Chem, Y K; Chua, K B; Malik, Y; Voon, K

    2015-06-01

    Monoclonal antibody-escape variant of dengue virus type 1 (MabEV DEN-1) was discovered and isolated in an outbreak of dengue in Klang Valley, Malaysia from December 2004 to March 2005. This study was done to investigate whether DEN152 (an isolate of MabEV DEN-1) is a product of recombination event or not. In addition, the non-synonymous mutations that correlate with the monoclonal antibody-escape variant were determined in this study. The genomes of DEN152 and two new DEN-1 isolates, DENB04 and DENK154 were completely sequenced, aligned, and compared. Phylogenetic tree was plotted and the recombination event on DEN152 was investigated. DEN152 is sub-grouped under genotype I and is closely related genetically to a DEN-1 isolated in Japan in 2004. DEN152 is not a recombinant product of any parental strains. Four amino acid substitutions were unique only to DEN 152. These amino acid substitutions were (Ser)[326](Leu), (Ser)[340](Leu) at the deduced E protein, (Ile)[250](Thr) at NS1 protein, and (Thr)[41](Ser) at NS5 protein. Thus, DEN152 is an isolate of the emerging monoclonal antibody-escape variant DEN-1 that escaped diagnostic laboratory detection. PMID:26691263

  17. Absolute Quantitation of Intact Recombinant Antibody Product Variants Using Mass Spectrometry.

    PubMed

    Macchi, Frank D; Yang, Feng; Li, Charlene; Wang, Chenchen; Dang, Anh Nguyen; Marhoul, Joseph C; Zhang, Hui-min; Tully, Timothy; Liu, Hongbin; Yu, X Christopher; Michels, David A

    2015-10-20

    Accurate and precise quantitative measurement of product-related variants of a therapeutic antibody is essential for product development and testing. Bispecific antibodies (bsAbs) are Abs composed of two different half antibody arms, each of which recognizes a distinct target, and recently they have attracted substantial therapeutic interest. Because of the increased complexity of its structure and its production process, as compared to a conventional monoclonal antibody, additional product-related variants, including covalent and noncovalent homodimers of half antibodies (hAbs), may be present in the bsAb product. Sufficient separation and reliable quantitation of these bsAb homodimers using liquid chromatography (LC) or capillary electrophoresis-based methods is challenging because these homodimer species and the bsAb often have similar physicochemical properties. Formation of noncovalent homodimers and heterodimers can also occur. In addition, since homodimers share common sequences with their corresponding halves and bsAb, it is not suitable to use peptides as surrogates for their quantitation. To tackle these analytical challenges, we developed a mass spectrometry-based quantitation method. Chip-based nanoflow LC-time-of-flight mass spectrometry coupled with a standard addition approach provided unbiased absolute quantitation of these drug-product-related variants. Two methods for the addition of known levels of standard (multi- or single-addition) were evaluated. Both methods demonstrated accurate and reproducible quantitation of homodimers at the 0.2% (w/w) level, with the single-addition method having the promise of higher analytical throughput. PMID:26376221

  18. Global and Local Conformation of Human IgG Antibody Variants Rationalizes Loss of Thermodynamic Stability.

    PubMed

    Edgeworth, Matthew J; Phillips, Jonathan J; Lowe, David C; Kippen, Alistair D; Higazi, Daniel R; Scrivens, James H

    2015-12-01

    Immunoglobulin G (IgG) monoclonal antibodies (mAbs) are a major class of medicines, with high specificity and affinity towards targets spanning many disease areas. The antibody Fc (fragment crystallizable) region is a vital component of existing antibody therapeutics, as well as many next generation biologic medicines. Thermodynamic stability is a critical property for the development of stable and effective therapeutic proteins. Herein, a combination of ion-mobility mass spectrometry (IM-MS) and hydrogen/deuterium exchange mass spectrometry (HDX-MS) approaches have been used to inform on the global and local conformation and dynamics of engineered IgG Fc variants with reduced thermodynamic stability. The changes in conformation and dynamics have been correlated with their thermodynamic stability to better understand the destabilising effect of functional IgG Fc mutations and to inform engineering of future therapeutic proteins. PMID:26482340

  19. Nucleotide changes in sequential variants of influenza virus hemagglutinin genes and molecular structures of corresponding monoclonal antibodies specific for each variant.

    PubMed Central

    Meek, K; Johansson, B; Schulman, J; Bona, C; Capra, J D

    1989-01-01

    We have generated four monoclonal antibodies specific for one or more members of a series of two sequentially derived PR8 influenza virus variants. Three of these antibodies share cross-reactive idiotypes. The amino acid sequences of these antibodies were determined, and it was found that two of these antibodies use genes from the VH7183 family, whereas the third uses a gene from the VHJ558 family. All four monoclonal antibodies derive from different families of genes encoding the variable region of the kappa chain. The RNA sequence of the parent PR8 virus as well as the RNA sequences of the sequential variants were also determined, and it was demonstrated that the variant hemagglutinin molecules differed from the parent molecule by only a single amino acid interchange. Despite these subtle differences in antigenic structures of hemagglutinin, and the cross-reactive idiotype of the antibodies, their primary structures were very different. These data reinforce the idea that a wide variety of antibody structures exist which are directed against subtly different structures in biologically important antigens. PMID:2471975

  20. Proteomic differences in recombinant CHO cells producing two similar antibody fragments.

    PubMed

    Sommeregger, Wolfgang; Mayrhofer, Patrick; Steinfellner, Willibald; Reinhart, David; Henry, Michael; Clynes, Martin; Meleady, Paula; Kunert, Renate

    2016-09-01

    Chinese hamster ovary (CHO) cells are the most commonly used mammalian hosts for the production of biopharmaceuticals. To overcome unfavorable features of CHO cells, a lot of effort is put into cell engineering to improve phenotype. "Omics" studies investigating elevated growth rate and specific productivities as well as extracellular stimulus have already revealed many interesting engineering targets. However, it remains largely unknown how physicochemical properties of the recombinant product itself influence the host cell. In this study, we used quantitative label-free LC-MS proteomic analyses to investigate product-specific proteome differences in CHO cells producing two similar antibody fragments. We established recombinant CHO cells producing the two antibodies, 3D6 and 2F5, both as single-chain Fv-Fc homodimeric antibody fragments (scFv-Fc). We applied three different vector strategies for transgene delivery (i.e., plasmid, bacterial artificial chromosome, recombinase-mediated cassette exchange), selected two best performing clones from transgene variants and transgene delivery methods and investigated three consecutively passaged cell samples by label-free proteomic analysis. LC-MS-MS profiles were compared in several sample combinations to gain insights into different aspects of proteomic changes caused by overexpression of two different heterologous proteins. This study suggests that not only the levels of specific product secretion but the product itself has a large impact on the proteome of the cell. Biotechnol. Bioeng. 2016;113: 1902-1912. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc. PMID:26913574

  1. Anti-CD25 monoclonal antibody Fc variants differentially impact regulatory T cells and immune homeostasis.

    PubMed

    Huss, David J; Pellerin, Alex F; Collette, Brian P; Kannan, Arun K; Peng, Liaomin; Datta, Abhishek; Wipke, Brian T; Fontenot, Jason D

    2016-07-01

    Interleukin-2 (IL-2) is a critical regulator of immune homeostasis through its non-redundant role in regulatory T (Treg) cell biology. There is major interest in therapeutic modulation of the IL-2 pathway to promote immune activation in the context of tumour immunotherapy or to enhance immune suppression in the context of transplantation, autoimmunity and inflammatory diseases. Antibody-mediated targeting of the high-affinity IL-2 receptor α chain (IL-2Rα or CD25) offers a direct mechanism to target IL-2 biology and is being actively explored in the clinic. In mouse models, the rat anti-mouse CD25 clone PC61 has been used extensively to investigate the biology of IL-2 and Treg cells; however, there has been controversy and conflicting data on the exact in vivo mechanistic function of PC61. Engineering antibodies to alter Fc/Fc receptor interactions can significantly alter their in vivo function. In this study, we re-engineered the heavy chain constant region of an anti-CD25 monoclonal antibody to generate variants with highly divergent Fc effector function. Using these anti-CD25 Fc variants in multiple mouse models, we investigated the in vivo impact of CD25 blockade versus depletion of CD25(+) Treg cells on immune homeostasis. We report that immune homeostasis can be maintained during CD25 blockade but aberrant T-cell activation prevails when CD25(+) Treg cells are actively depleted. These results clarify the impact of PC61 on Treg cell biology and reveal an important distinction between CD25 blockade and depletion of CD25(+) Treg cells. These findings should inform therapeutic manipulation of the IL-2 pathway by targeting the high-affinity IL-2R. PMID:27012310

  2. A LAIR-1 insertion generates broadly reactive antibodies against malaria variant antigens

    PubMed Central

    Abdi, Abdirahman; Perez, Mathilde Foglierini; Geiger, Roger; Tully, Claire Maria; Jarrossay, David; Maina Ndungu, Francis; Wambua, Juliana; Bejon, Philip; Fregni, Chiara Silacci; Fernandez-Rodriguez, Blanca; Barbieri, Sonia; Bianchi, Siro; Marsh, Kevin; Thathy, Vandana; Corti, Davide; Sallusto, Federica

    2016-01-01

    Plasmodium falciparum antigens expressed on the surface of infected erythrocytes are important targets of naturally acquired immunity against malaria, but their high number and variability provide the pathogen with a powerful means of escape from host antibodies1–4. Although broadly reactive antibodies against these antigens could be useful as therapeutics and in vaccine design, their identification has proven elusive. Here, we report the isolation of human monoclonal antibodies that recognize erythrocytes infected by different P. falciparum isolates and opsonize these cells by binding to members of the RIFIN family. These antibodies acquired broad reactivity through a novel mechanism of insertion of a large DNA fragment between the V and DJ segments. The insert, which is both necessary and sufficient for binding to RIFINs, encodes the entire 100 amino acid collagen-binding domain of LAIR-1, an Ig superfamily inhibitory receptor encoded on chromosome 19. In each of the two donors studied, the antibodies are produced by a single expanded B cell clone and carry distinct somatic mutations in the LAIR-1 domain that abolish binding to collagen and increase binding to infected erythrocytes. These findings illustrate, with a biologically relevant example, a novel mechanism of antibody diversification by interchromosomal DNA transposition and demonstrate the existence of conserved epitopes that may be suitable candidates for the development of a malaria vaccine. PMID:26700814

  3. A LAIR1 insertion generates broadly reactive antibodies against malaria variant antigens.

    PubMed

    Tan, Joshua; Pieper, Kathrin; Piccoli, Luca; Abdi, Abdirahman; Foglierini, Mathilde; Geiger, Roger; Tully, Claire Maria; Jarrossay, David; Ndungu, Francis Maina; Wambua, Juliana; Bejon, Philip; Fregni, Chiara Silacci; Fernandez-Rodriguez, Blanca; Barbieri, Sonia; Bianchi, Siro; Marsh, Kevin; Thathy, Vandana; Corti, Davide; Sallusto, Federica; Bull, Peter; Lanzavecchia, Antonio

    2016-01-01

    Plasmodium falciparum antigens expressed on the surface of infected erythrocytes are important targets of naturally acquired immunity against malaria, but their high number and variability provide the pathogen with a powerful means of escape from host antibodies. Although broadly reactive antibodies against these antigens could be useful as therapeutics and in vaccine design, their identification has proven elusive. Here we report the isolation of human monoclonal antibodies that recognize erythrocytes infected by different P. falciparum isolates and opsonize these cells by binding to members of the RIFIN family. These antibodies acquired broad reactivity through a novel mechanism of insertion of a large DNA fragment between the V and DJ segments. The insert, which is both necessary and sufficient for binding to RIFINs, encodes the entire 98 amino acid collagen-binding domain of LAIR1, an immunoglobulin superfamily inhibitory receptor encoded on chromosome 19. In each of the two donors studied, the antibodies are produced by a single expanded B-cell clone and carry distinct somatic mutations in the LAIR1 domain that abolish binding to collagen and increase binding to infected erythrocytes. These findings illustrate, with a biologically relevant example, a novel mechanism of antibody diversification by interchromosomal DNA transposition and demonstrate the existence of conserved epitopes that may be suitable candidates for the development of a malaria vaccine. PMID:26700814

  4. Mechanistic modeling of ion-exchange process chromatography of charge variants of monoclonal antibody products.

    PubMed

    Kumar, Vijesh; Leweke, Samuel; von Lieres, Eric; Rathore, Anurag S

    2015-12-24

    Ion-exchange chromatography (IEX) is universally accepted as the optimal method for achieving process scale separation of charge variants of a monoclonal antibody (mAb) therapeutic. These variants are closely related to the product and a baseline separation is rarely achieved. The general practice is to fractionate the eluate from the IEX column, analyze the fractions and then pool the desired fractions to obtain the targeted composition of variants. This is, however, a very cumbersome and time consuming exercise. A mechanistic model that is capable of simulating the peak profile will be a much more elegant and effective way to make a decision on the pooling strategy. This paper proposes a mechanistic model, based on the general rate model, to predict elution peak profile for separation of the main product from its variants. The proposed approach uses inverse fit of process scale chromatogram for estimation of model parameters using the initial values that are obtained from theoretical correlations. The packed bed column has been modeled along with the chromatographic system consisting of the mixer, tubing and detectors as a series of dispersed plug flow and continuous stirred tank reactors. The model uses loading ranges starting at 25% to a maximum of 70% of the loading capacity and hence is applicable to process scale separations. Langmuir model has been extended to include the effects of salt concentration and temperature on the model parameters. The extended Langmuir model that has been proposed uses one less parameter than the SMA model and this results in a significant ease of estimating the model parameters from inverse fitting. The proposed model has been validated with experimental data and has been shown to successfully predict peak profile for a range of load capacities (15-28mg/mL), gradient lengths (10-30CV), bed heights (6-20cm), and for three different resins with good accuracy (as measured by estimation of residuals). The model has been also

  5. Specific antibody for pesticide residue determination produced by antibody-pesticide complex

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new method for specific antibody production was developed using antibody (Ab)-pesticide complex as a unique immunogen. Parathion (PA) was the targeted pesticide, and rabbit polyclonal antibody (Pab) and mouse monoclonal antibody (Mab) were used as carrier proteins. The Ab-PA complexes were genera...

  6. Subgroup J avian leukosis virus neutralizing antibody escape variants contribute to viral persistence in meat-type chickens.

    PubMed

    Pandiri, A R; Mays, J K; Silva, R F; Hunt, H D; Reed, W M; Fadly, A M

    2010-06-01

    We have previously demonstrated a high incidence of chickens with persistent viremia even in the presence of neutralizing antibodies (V+A+) against the inoculated parental virus in commercial meat-type chickens inoculated at hatch with subgroup J avian leukosis virus (ALV J) field isolates. In this study, we used an ALV J molecular clone, ADOL pR5-4, to determine the role of neutralizing antibody (NAb) escape mutants in maintaining a high incidence of viral persistence, namely, V+A+ infection profile in commercial meat-type chickens. Chickens were housed as a flock in a pen or housed in isolation in solitary Horsfall-Bauer units for testing for NAb escape variants. The emergence of NAb escape variants was evaluated by sequential autologous virus neutralization (VN) (between virus and antibody from the same sampling period) and heterologous VN (between virus and antibody from preceding and succeeding sampling periods). Sequential virus isolates and corresponding antisera from 18 chickens were examined by VN matrix. In all chickens, autologous virus isolates were not neutralized by corresponding antisera. However, some of these resilient autologous virus isolates were neutralized by antibodies from subsequent sampling intervals. Nucleotide sequence analysis of consecutive isolates from three individually housed chickens with V+A+ infection profile revealed distinct changes within the envelope region, suggesting viral evolution to escape the host immune response. These results demonstrate that the emergence of antibody escape variants in commercial meat-type chickens contributes to ALV J persistence. PMID:20608529

  7. Detection of influenza antigenic variants directly from clinical samples using polyclonal antibody based proximity ligation assays

    PubMed Central

    Martin, Brigitte E.; Jia, Kun; Sun, Hailiang; Ye, Jianqiang; Hall, Crystal; Ware, Daphne; Wan, Xiu-Feng

    2016-01-01

    Identification of antigenic variants is the key to a successful influenza vaccination program. The empirical serological methods to determine influenza antigenic properties require viral propagation. Here a novel quantitative PCR-based antigenic characterization method using polyclonal antibody and proximity ligation assays, or so-called polyPLA, was developed and validated. This method can detect a viral titer that is less than 1000 TCID50/mL. Not only can this method differentiate between different HA subtypes of influenza viruses but also effectively identify antigenic drift events within the same HA subtype of influenza viruses. Applications in H3N2 seasonal influenza data showed that the results from this novel method are consistent with those from the conventional serological assays. This method is not limited to the detection of antigenic variants in influenza but also other pathogens. It has the potential to be applied through a large-scale platform in disease surveillance requiring minimal biosafety and directly using clinical samples. PMID:25546251

  8. Monoclonal antibody characterization of a leukoagglutinin produced by Renibacterium salmoninarum.

    PubMed

    Wiens, G D; Kaattari, S L

    1991-02-01

    Renibacterium salmoninarum causes a chronic disease of salmonid fish known as bacterial kidney disease. High concentrations of bacterially produced extracellular protein (ECP) are present in plasma, kidney, and spleen tissue of naturally and experimentally infected fish. ECP agglutinated salmonid leukocytes in vitro at concentrations which correspond to levels found in highly infected fish. Association of biological activity with the structure of the major protein constituent of ECP, p57, was accomplished by monoclonal antibody (MAb) analysis. Location of the antigenic binding sites recognized by the MAbs was determined by two-dimensional electrophoresis and Western immunoblotting of the proteolytic breakdown fragments of p57. Eight MAbs have been classified into three groups on the basis of their differential recognition of these proteolytic breakdown products. Group I MAbs bound a region proximal to the amino terminus of the protein. Two of these MAbs were also able to block leukoagglutinating activity. Group III MAbs bound to a region associated with the bacterial cell surface, while group II MAbs bound a region between group I and group III. These analyses have allowed the identification of potential structural and functional regions of p57. PMID:1987079

  9. Monoclonal antibody characterization of a leukoagglutinin produced by Renibacterium salmoninarum.

    PubMed Central

    Wiens, G D; Kaattari, S L

    1991-01-01

    Renibacterium salmoninarum causes a chronic disease of salmonid fish known as bacterial kidney disease. High concentrations of bacterially produced extracellular protein (ECP) are present in plasma, kidney, and spleen tissue of naturally and experimentally infected fish. ECP agglutinated salmonid leukocytes in vitro at concentrations which correspond to levels found in highly infected fish. Association of biological activity with the structure of the major protein constituent of ECP, p57, was accomplished by monoclonal antibody (MAb) analysis. Location of the antigenic binding sites recognized by the MAbs was determined by two-dimensional electrophoresis and Western immunoblotting of the proteolytic breakdown fragments of p57. Eight MAbs have been classified into three groups on the basis of their differential recognition of these proteolytic breakdown products. Group I MAbs bound a region proximal to the amino terminus of the protein. Two of these MAbs were also able to block leukoagglutinating activity. Group III MAbs bound to a region associated with the bacterial cell surface, while group II MAbs bound a region between group I and group III. These analyses have allowed the identification of potential structural and functional regions of p57. Images PMID:1987079

  10. Recognition of influenza H3N2 variant virus by human neutralizing antibodies

    PubMed Central

    Bangaru, Sandhya; Nieusma, Travis; Kose, Nurgun; Thornburg, Natalie J.; Finn, Jessica A.; Kaplan, Bryan S.; King, Hannah G.; Singh, Vidisha; Lampley, Rebecca M.; Sapparapu, Gopal; Cisneros, Alberto; Edwards, Kathryn M.; Slaughter, James C.; Edupuganti, Srilatha; Lai, Lilin; Richt, Juergen A.; Webby, Richard J.; Ward, Andrew B.; Crowe, James E.

    2016-01-01

    Since 2011, over 300 human cases of infection, especially in exposed children, with the influenza A H3N2 variant (H3N2v) virus that circulates in swine in the US have been reported. The structural and genetic basis for the lack of protection against H3N2v induced by vaccines containing seasonal H3N2 antigens is poorly understood. We isolated 17 human monoclonal antibodies (mAbs) that neutralized H3N2v virus from subjects experimentally immunized with an H3N2v candidate vaccine. Six mAbs exhibited very potent neutralizing activity (IC50 < 200 ng/ml) against the H3N2v virus but not against current human H3N2 circulating strains. Fine epitope mapping and structural characterization of antigen-antibody complexes revealed that H3N2v specificity was attributable to amino acid polymorphisms in the 150-loop and the 190-helix antigenic sites on the hemagglutinin protein. H3N2v-specific antibodies also neutralized human H3N2 influenza strains naturally circulating between 1995 and 2005. These results reveal a high level of antigenic relatedness between the swine H3N2v virus and previously circulating human strains, consistent with the fact that early human H3 seasonal strains entered the porcine population in the 1990s and reentered the human population, where they had not been circulating, as H3N2v about a decade later. The data also explain the increased susceptibility to H3N2v viruses in young children, who lack prior exposure to human seasonal strains from the 1990s. PMID:27482543

  11. Genetic variants are major determinants of CSF antibody levels in multiple sclerosis

    PubMed Central

    Pauwels, Ine; Gustavsen, Marte W.; van Son, Brechtje; Hilven, Kelly; Bos, Steffan D.; Celius, Elisabeth Gulowsen; Berg-Hansen, Pål; Aarseth, Jan; Myhr, Kjell-Morten; D’Alfonso, Sandra; Barizzone, Nadia; Leone, Maurizio A.; Martinelli Boneschi, Filippo; Sorosina, Melissa; Liberatore, Giuseppe; Kockum, Ingrid; Olsson, Tomas; Hillert, Jan; Alfredsson, Lars; Bedri, Sahl Khalid; Hemmer, Bernhard; Buck, Dorothea; Berthele, Achim; Knier, Benjamin; Biberacher, Viola; van Pesch, Vincent; Sindic, Christian; Bang Oturai, Annette; Søndergaard, Helle Bach; Sellebjerg, Finn; Jensen, Poul Erik H.; Comabella, Manuel; Montalban, Xavier; Pérez-Boza, Jennifer; Malhotra, Sunny; Lechner-Scott, Jeannette; Broadley, Simon; Slee, Mark; Taylor, Bruce; Kermode, Allan G.; Gourraud, Pierre-Antoine; Sawcer, Stephen J.; Andreassen, Bettina Kullle; Dubois, Bénédicte; Harbo, Hanne F.

    2015-01-01

    Immunological hallmarks of multiple sclerosis include the production of antibodies in the central nervous system, expressed as presence of oligoclonal bands and/or an increased immunoglobulin G index—the level of immunoglobulin G in the cerebrospinal fluid compared to serum. However, the underlying differences between oligoclonal band-positive and -negative patients with multiple sclerosis and reasons for variability in immunoglobulin G index are not known. To identify genetic factors influencing the variation in the antibody levels in the cerebrospinal fluid in multiple sclerosis, we have performed a genome-wide association screen in patients collected from nine countries for two traits, presence or absence of oligoclonal bands (n = 3026) and immunoglobulin G index levels (n = 938), followed by a replication in 3891 additional patients. We replicate previously suggested association signals for oligoclonal band status in the major histocompatibility complex region for the rs9271640*A-rs6457617*G haplotype, correlated with HLA-DRB1*1501, and rs34083746*G, correlated with HLA-DQA1*0301 (P comparing two haplotypes = 8.88 × 10−16). Furthermore, we identify a novel association signal of rs9807334, near the ELAC1/SMAD4 genes, for oligoclonal band status (P = 8.45 × 10−7). The previously reported association of the immunoglobulin heavy chain locus with immunoglobulin G index reaches strong evidence for association in this data set (P = 3.79 × 10−37). We identify two novel associations in the major histocompatibility complex region with immunoglobulin G index: the rs9271640*A-rs6457617*G haplotype (P = 1.59 × 10−22), shared with oligoclonal band status, and an additional independent effect of rs6457617*G (P = 3.68 × 10−6). Variants identified in this study account for up to 2-fold differences in the odds of being oligoclonal band positive and 7.75% of the variation in immunoglobulin G index. Both traits are associated with clinical features of disease such

  12. Viral variants that initiate and drive maturation of V1V2-directed HIV-1 broadly neutralizing antibodies

    PubMed Central

    Bhiman, Jinal N.; Anthony, Colin; Doria-Rose, Nicole A.; Karimanzira, Owen; Schramm, Chaim A.; Khoza, Thandeka; Kitchin, Dale; Botha, Gordon; Gorman, Jason; Garrett, Nigel J.; Abdool Karim, Salim S.; Shapiro, Lawrence; Williamson, Carolyn; Kwong, Peter D.; Mascola, John R.; Morris, Lynn; Moore, Penny L.

    2015-01-01

    The elicitation of broadly neutralizing antibodies (bNAbs) is likely to be essential for a preventative HIV-1 vaccine, but this has not yet been achieved by immunization. In contrast some HIV-1-infected individuals naturally mount bNAb responses during chronic infection, suggesting that years of maturation are required for breadth1-6. Recent studies have shown that viral diversification precedes the emergence of bNAbs but the significance of this observation is unknown7,8. Here, we delineate the key viral events that drove neutralization breadth within the CAP256-VRC26 family of 33 monoclonal antibodies (mAbs) isolated from a superinfected individual. First, we identified minority viral variants that were distinct from both transmitted/founder (T/F) viruses and efficiently engaged the bNAb precursor, termed bNAb-initiating envelopes. Second, deep sequencing revealed a pool of diverse epitope variants (immunotypes) that were preferentially neutralized by broader members of the antibody lineage. In contrast, a “dead-end” antibody sublineage unable to neutralize these immunotypes showed limited evolution and failed to develop breadth. Thus, early viral escape at key antibody-virus contact sites selects for sublineages that can tolerate these changes, providing a new mechanism for the generation of neutralization breadth within a developing antibody lineage. PMID:26457756

  13. Rapid identification of an antibody DNA construct rearrangement sequence variant by mass spectrometry.

    PubMed

    Scott, Rebecca A; Rogers, Rich; Balland, Alain; Brady, Lowell J

    2014-01-01

    During cell line development for an IgG1 antibody candidate (mAb1), a C-terminal extension was identified in 2 product candidate clones expressed in CHO-K1 cell line. The extension was initially observed as the presence of anomalous new peaks in these clones after analysis by cation exchange chromatography (CEX-HPLC) and reduced capillary electrophoresis (rCE-SDS). Reduced mass analysis of these CHO-K1 clones revealed that a larger than expected mass was present on a sub-population of the heavy chain species, which could not be explained by any known chemical or post-translational modifications. It was suspected that this additional mass on the heavy chain was due to the presence of an additional amino acid sequence. To identify the suspected additional sequence, de novo sequencing in combination with proteomic searching was performed against translated DNA vectors for the heavy chain and light chain. Peptides unique to the clones containing the extension were identified matching short sequences (corresponding to 9 and 35 amino acids, respectively) from 2 non-coding sections of the light chain vector construct. After investigation, this extension was observed to be due to the re-arrangement of the DNA construct, with the addition of amino acids derived from the light chain vector non-translated sequence to the C-terminus of the heavy chain. This observation showed the power of proteomic mass spectrometric techniques to identify an unexpected antibody sequence variant using de novo sequencing combined with database searching, and allowed for rapid identification of the root cause for new peaks in the cation exchange and rCE-SDS assays. PMID:25484040

  14. Integrated microfluidic capillary electrophoresis-electrospray ionization devices with online MS detection for the separation and characterization of intact monoclonal antibody variants.

    PubMed

    Redman, Erin A; Batz, Nicholas G; Mellors, J Scott; Ramsey, J Michael

    2015-02-17

    Here, we demonstrate an integrated microfluidic capillary electrophoresis-electrospray ionization (CE-ESI) device for the separation of intact monoclonal antibody charge variants with online mass spectrometric (MS) identification. The need for dynamic coating and zwitterionic background electrolyte (BGE) additives has been eliminated by utilizing surface chemistry within the device channels to control analyte adsorption and electroosmotic flow (EOF) while maintaining separation efficiency. The effectiveness of this strategy was illustrated with the separation of charge variants of Infliximab. Three major species corresponding to C-terminal lysine variants were separated with an average resolution of 0.80 and identified by mass difference. In addition to the lysine variants, masses were determined for minor acidic and basic species. The separation of these variants prior to MS analysis facilitated the identification of glycosylation patterns for each of the variants. The general applicability of this method was demonstrated by analyzing two additional monoclonal antibody species: an IgG2 antibody and an IgG1 antibody conjugate. The IgG2 proved to have similar modifications to Infliximab with lower relative abundances of the lysine variants. Analysis of the IgG1 drug conjugate further exemplified the advantages of MS detection; differences in the extent of antibody conjugation were detectable despite limited CE resolution. The CE-ESI-MS methodology described here is a rapid and generic strategy for the separation of intact mAb charge variants and facilitates the identification of variants through MS detection. PMID:25569459

  15. Identifying bottlenecks in transient and stable production of recombinant monoclonal-antibody sequence variants in Chinese hamster ovary cells

    PubMed Central

    Mason, Megan; Sweeney, Bernadette; Cain, Katharine; Stephens, Paul; Sharfstein, Susan T.

    2012-01-01

    The increasing demand for antibody-based therapeutics has emphasized the need for technologies to improve recombinant antibody titers from mammalian cell lines. Moreover, as antibody therapeutics address an increasing spectrum of indications, interest has increased in antibody engineering to improve affinity and biological activity. However, the cellular mechanisms that dictate expression and the relationships between antibody sequence and expression level remain poorly understood. Fundamental understanding of how mammalian cells handle high levels of transgene expression and of the relationship between sequence and expression are vital to the development of new antibodies and for increasing recombinant antibody titers. In this work, we analyzed a pair of mutants that vary by a single amino acid at Kabat position 49 (heavy chain framework), resulting in differential transient and stable titers with no apparent loss of antigen affinity. Through analysis of mRNA, gene copy number, intracellular antibody content, and secreted antibody, we found that while translational/post-translational mechanisms are limiting in transient systems, it appears that the amount of available transgenic mRNA becomes the limiting event upon stable integration of the recombinant genes. We also show that amino acid substitution at residue 49 results in production of a non-secreted HC variant and postulate that stable antibody expression is maintained at a level which prevents toxic accumulation of this HC-related protein. This study highlights the need for proper sequence engineering strategies when developing therapeutic antibodies and alludes to the early analysis of transient expression systems to identify the potential for aberrant stable expression behavior. PMID:22467228

  16. Characterization of monoclonal antibodies produced against Avian metapneumovirus Sybtype C

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monoclonal antibodies (MAbs) were prepared against avian metapneumovirus (aMPV) subtype C (aMPV/Minnesota/turkey/1a/97). Six MAbs were selected based on ELISA activities and characterized by isotyping, neutralization test, Western blot analysis, and immunohistochemistry (IHC) assay. The results show...

  17. Epstein-Barr virus-transformed human B lymphocytes produce natural antibodies to histones.

    PubMed

    Garzelli, C; Incaprera, M; Bazzichi, A; Manunta, M; Rognini, F; Falcone, G

    1994-03-01

    To study the mechanism(s) responsible for the appearance of Epstein-Barr virus (EBV)-induced anti-histone autoantibodies, peripheral blood B lymphocytes from healthy donors were infected with EBV and the resulting lymphoblastoid cell lines were tested for secretion of antibodies reacting with histones. It was found that EBV-transformed cells produce IgM antibody reactive with histones and that the frequency of EBV-inducible circulating B lymphocytes that produce antibodies to histones is at least 10(-5). Moreover, in cultures of tonsillar lymphoid cells, the enrichment in CD5+ B lymphocytes increases the percentage of EBV-transformed cultures making anti-histone IgM antibodies. EBV may therefore, also in vivo, induce natural anti-histone antibody by polyclonal B-cell activation without any requirement of antigen to trigger antibody response. PMID:7518420

  18. Envelope Variants Circulating as Initial Neutralization Breadth Developed in Two HIV-Infected Subjects Stimulate Multiclade Neutralizing Antibodies in Rabbits

    PubMed Central

    Malherbe, Delphine C.; Pissani, Franco; Sather, D. Noah; Guo, Biwei; Pandey, Shilpi; Sutton, William F.; Stuart, Andrew B.; Robins, Harlan; Park, Byung; Krebs, Shelly J.; Schuman, Jason T.; Kalams, Spyros; Hessell, Ann J.

    2014-01-01

    ABSTRACT Identifying characteristics of the human immunodeficiency virus type 1 (HIV-1) envelope that are effective in generating broad, protective antibodies remains a hurdle to HIV vaccine design. Emerging evidence of the development of broad and potent neutralizing antibodies in HIV-infected subjects suggests that founder and subsequent progeny viruses may express unique antigenic motifs that contribute to this developmental pathway. We hypothesize that over the course of natural infection, B cells are programmed to develop broad antibodies by exposure to select populations of emerging envelope quasispecies variants. To test this hypothesis, we identified two unrelated subjects whose antibodies demonstrated increasing neutralization breadth against a panel of HIV-1 isolates over time. Full-length functional env genes were cloned longitudinally from these subjects from months after infection through 2.6 to 5.8 years of infection. Motifs associated with the development of breadth in published, cross-sectional studies were found in both subjects. We compared the immunogenicity of envelope vaccines derived from time points obtained during and after broadening of neutralization activity within these subjects. Rabbits were coimmunized four times with selected multiple gp160 DNAs and gp140-trimeric envelope proteins. The affinity of the polyclonal response increased as a function of boosting. The most rapid and persistent neutralization of multiclade tier 1 viruses was elicited by envelopes that were circulating in plasma at time points prior to the development of 50% neutralization breadth in both human subjects. The breadth elicited in rabbits was not improved by exposure to later envelope variants. These data have implications for vaccine development in describing a target time point to identify optimal envelope immunogens. IMPORTANCE Vaccine protection against viral infections correlates with the presence of neutralizing antibodies; thus, vaccine components capable

  19. Should charge variants of monoclonal antibody therapeutics be considered critical quality attributes?

    PubMed

    Singh, Sumit Kumar; Narula, Gunjan; Rathore, Anurag S

    2016-09-01

    Charge variants, namely acidic and basic variants, are typically found in mAb therapeutics. Charge heterogeneity is typically not regarded to affect safety and efficacy of the product. As a result, the commonly followed approach involves assignment of a specification for the variants based on statistical analysis of variability in levels that is seen during commercial manufacturing. This is followed by monitoring of product quality to demonstrate consistency. This paper aims to demonstrate that this perception of charge variants warrants a more in-depth investigation to evaluate the role charge variants play in safety and efficacy of a mAb therapeutic. In addition, a novel procedure has been suggested for making this assessment and alleviate the problems that are traditionally faced when isolating these variants for characterization. The suggested procedure utilizes the principles of bioseparations, cell biology, and statistics and it is demonstrated that this is significantly more efficient than the approach practiced today. PMID:27387433

  20. Improved variants of SrtA for site-specific conjugation on antibodies and proteins with high efficiency.

    PubMed

    Chen, Long; Cohen, Justin; Song, Xiaoda; Zhao, Aishan; Ye, Zi; Feulner, Christine J; Doonan, Patrick; Somers, Will; Lin, Laura; Chen, Peng R

    2016-01-01

    Sortase mediated ligation is a highly specific platform for conjugation that relies on the specificity of the transpeptidase Sortase A (SrtA) for short peptide sequences (LPXTG and GGG). SrtA retains its specificity while accepting a wide range of potential substrates, but its broad use is limited by the wild-type enzyme's poor kinetics, which require large amounts of SrtA and extended reaction times for efficient conjugation. Prior explorations have aimed to improve the kinetics of SrtA with limited success. Herein we describe the discovery of further improved SrtA variants with increased efficiency for the conjugation reaction, and demonstrate their robustness in labelling proteins and antibodies in a site-specific manner. Our variants require significantly lower amounts of enzyme than WT SrtA and can be used to attach small molecules to the N or C-terminus of the heavy or light chain in antibodies with excellent yields. These improved variants can also be used for highly efficient site-specific PEGylation. PMID:27534437

  1. Improved variants of SrtA for site-specific conjugation on antibodies and proteins with high efficiency

    PubMed Central

    Chen, Long; Cohen, Justin; Song, Xiaoda; Zhao, Aishan; Ye, Zi; Feulner, Christine J.; Doonan, Patrick; Somers, Will; Lin, Laura; Chen, Peng R.

    2016-01-01

    Sortase mediated ligation is a highly specific platform for conjugation that relies on the specificity of the transpeptidase Sortase A (SrtA) for short peptide sequences (LPXTG and GGG). SrtA retains its specificity while accepting a wide range of potential substrates, but its broad use is limited by the wild-type enzyme’s poor kinetics, which require large amounts of SrtA and extended reaction times for efficient conjugation. Prior explorations have aimed to improve the kinetics of SrtA with limited success. Herein we describe the discovery of further improved SrtA variants with increased efficiency for the conjugation reaction, and demonstrate their robustness in labelling proteins and antibodies in a site-specific manner. Our variants require significantly lower amounts of enzyme than WT SrtA and can be used to attach small molecules to the N or C-terminus of the heavy or light chain in antibodies with excellent yields. These improved variants can also be used for highly efficient site-specific PEGylation. PMID:27534437

  2. Protein adsorption on ion exchange resins and monoclonal antibody charge variant modulation.

    PubMed

    Guélat, Bertrand; Khalaf, Rushd; Lattuada, Marco; Costioli, Matteo; Morbidelli, Massimo

    2016-05-20

    A novel multicomponent adsorption equilibrium model for proteins on ion-exchange resins is developed on a statistical thermodynamic basis including surface coverage effects and protein-resin and protein-protein interactions. The resulting model exhibits a general competitive Langmuirian behavior and was applied to the study and optimization of the separation of monoclonal antibody charge variants on two strong cation exchangers. The model accounts explicitly for the effect of both pH and salt concentration, and its parameters can be determined in diluted conditions, that is, through physically sound assumptions, all model parameters can be obtained using solely experiments in diluted conditions, and be used to make predictions in overloaded conditions. The parameterization of the model and optimization of the separation is based on a two-step approach. First, gradient experiments in diluted conditions are undertaken in order to determine the model parameters. Based on these experiments and on information about the proteins of interest and the stationary phase used, all the model parameters can be estimated. Second, using the parameterized model, an initial Pareto optimization is undertaken where overloaded operating conditions are investigated. Experiments from this Pareto set are then used to refine the estimation of the model parameters. A second Pareto optimization can then be undertaken, this time with the refined parameters. This can be repeated until a satisfactory set of model parameters is found. This iterative approach is shown to be extremely efficient and to provide large amounts of knowledge based on only a few experiments. It is shown that due to the strong physical foundation of the model and the very low number of adjustable parameters, the number of iterations is expected to be at most two or three. Furthermore, the model based tool is improved as more experimental knowledge is provided, allowing for better estimations of the chromatographic

  3. IGF2BP2 Alternative Variants Associated with Glutamic Acid Decarboxylase Antibodies Negative Diabetes in Malaysian Subjects

    PubMed Central

    Salem, Sameer D.; Saif-Ali, Riyadh; Ismail, Ikram S.; Al-Hamodi, Zaid; Poh, Rozaida; Muniandy, Sekaran

    2012-01-01

    Background The association of Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) common variants (rs4402960 and rs1470579) with type 2 diabetes (T2D) has been performed in different populations. The aim of this study was to evaluate the association of alternative variants of IGF2BP2; rs6777038, rs16860234 and rs7651090 with glutamic acid decarboxylase antibodies (GADA) negative diabetes in Malaysian Subjects. Methods/Principal Findings IGF2BP2; rs6777038, rs16860234 and rs7651090 single nucleotide polymorphisms (SNPs) were genotyped in 1107 GADA negative diabetic patients and 620 control subjects of Asian from Malaysia. The additive genetic model adjusted for age, race, gender and BMI showed that alternative variants; rs6777038, rs16860234 and rs7651090 of IGF2BP2 associated with GADA negative diabetes (OR = 1.21; 1.36; 1.35, P = 0.03; 0.0004; 0.0002, respectively). In addition, the CCG haplotype and diplotype CCG-TCG increased the risk of diabetes (OR = 1.51, P = 0.01; OR = 2.36, P = 0.009, respectively). Conclusions/Significance IGF2BP2 alternative variants were associated with GADA negative diabetes. The IGF2BP2 haplotypes and diplotypes increased the risk of diabetes in Malaysian subject. PMID:23029108

  4. Comparison of three adjuvants used to produce polyclonal antibodies to veterinary drugs.

    PubMed

    Fodey, Terence L; Delahaut, Philippe; Charlier, Caroline; Elliott, Christopher T

    2008-03-15

    Two commercially available adjuvants, Gerbu LQ 3000 and Montanide ISA 50V, were assessed as potential replacements for Freund's adjuvant by evaluating their efficacy in the production of polyclonal antibodies to veterinary drugs in rabbits. The aim was to find an adjuvant that could produce a similar (or enhanced) immune response in the host animal without the undesirable side effects associated with Freund's complete and incomplete adjuvant. The assessment involved the examination of each injection site and the characterisation of the resultant antibodies with regards to antibody titre and sensitivity. It was found that the rabbits immunised with Gerbu adjuvant produced some of the most sensitive antibodies. However, titres were relatively low and adverse effects at injection sites were relatively common. Montanide adjuvant produced no adverse effects and the related antibodies were found to be of adequate sensitivity when compared to those from rabbits immunised with Freund's. It was concluded that Montanide ISA 50V could be considered as a suitable replacement to Freund's for the production of polyclonal antibodies, to low molecular weight compounds in rabbits. PMID:18063100

  5. Cells that produce deleterious autoreactive antibodies are vulnerable to suicide.

    PubMed

    Niu, Haitao; Leung, Danny T M; Ma, Chun Hung; Law, Eric C Y; Tam, Frankie C H; Lim, Pak-Leong

    2008-08-01

    It is puzzling how autoreactive B cells that escape self-tolerance mechanisms manage to produce Abs that target vital cellular processes without succumbing themselves to the potentially deleterious effects of these proteins. We report that censorship indeed exists at this level: when the Ab synthesis in the cell is up-regulated in IL-6-enriched environments (e.g., adjuvant-primed mouse peritoneum), the cell dies of the increased intracellular binding between the Ab and the cellular autoantigen. In the case in which telomerase is the autoantigen, mouse hybridoma cells synthesizing such an autoantibody, which appeared to grow well in culture, could not grow in syngeneic BALB/c mice to form ascites, but grew nevertheless in athymic siblings. Culture experiments demonstrated that peritoneal cell-derived IL-6 (and accessory factors) affected the growth and functions of the hybridoma cells, including the induction of mitochondria-based apoptosis. Electron microscopy revealed an abundance of Abs in the nuclear chromatin of IL-6-stimulated cells, presumably piggy-backed there by telomerase from the cytosol. This nuclear presence was confirmed by light microscopy analysis of isolated nuclei. In two other cases, hybridoma cells synthesizing an autoantibody to GTP or osteopontin also showed similar growth inhibition in vivo. In all cases, Ab function was crucial to the demise of the cells. Thus, autoreactive cells, which synthesize autoantibodies to certain intracellular Ags, live delicately between life and death depending on the cytokine microenvironment. Paradoxically, IL-6, which is normally growth-potentiating for B cells, is proapoptotic for these cells. The findings reveal potential strategies and targets for immunotherapy. PMID:18641365

  6. [The development of methods for obtaining monoclonal antibody-producing cells].

    PubMed

    Skowicki, Michał; Lipiński, Tomasz

    2016-01-01

    Monoclonal antibodies (mAbs) are biomolecules of great scientific and practical significance. In contrast to polyclonal antibodies from immune sera, they are homogeneous and monospecific, since they are produced by hybridoma cells representing a clone arising from a single cell. The successful technology was described for the first time in 1975; the inventors were later awarded the Nobel Prize. Currently, mAbs are broadly used as a research tool, in diagnostics and medicine in particular for the treatment of cancer or in transplantology. About 47 therapeutics based on monoclonal antibodies are now available in the US and Europe, and the number is still growing. Production of monoclonal antibodies is a multistage, time-consuming and costly process. Growing demand for these molecules creates space for research focused on improvements in hybridoma technology. Lower costs, human labor, and time are important goals of these attempts. In this article, a brief review of current methods and their advances is given. PMID:27117113

  7. Comparison of antibody molecules produced from two cell lines with contrasting productivities and aggregate contents.

    PubMed

    Ishii, Yoichi; Imamoto, Yasufumi; Yamamoto, Rie; Tsukahara, Masayoshi; Wakamatsu, Kaori

    2015-01-01

    Cell culture processes that produce therapeutic antibodies with high productivity (titer) and low aggregate content reduce the risk of adverse effects and expense to patients. To elucidate the mechanism of aggregate formation, we compared trastuzumab samples produced from two contrasting cell lines: cell line A, which exhibits high titer and low aggregate content, and cell line B, which exhibits low titer and high aggregate content. Cell line B produced significantly fewer (approximately 1/3) antibodies compared with cell line A and contained higher (approximately 3-fold) percentages of aggregates. The aggregates of antibodies found in the protein A-purified samples of cell line B were associated mostly with noncovalent interactions. Cell line B exhibited a low content of monomers/dimers of light chains in the medium and within cells. Because light chains are essential for the correct folding of heavy chains and secretion of mature antibodies, the characteristics of cell line B may be attributed to low levels of light chain production. In addition, protein A-purified antibodies from cell line B (but not those from cell line A) contained fragments that are expected to expose the hydrophobic CH3 domain, which may serve as nuclei for aggregation. PMID:25501618

  8. Preferential association of a functional variant in complement receptor 2 with antibodies to double-stranded DNA

    PubMed Central

    Zhao, Jian; Giles, Brendan M; Taylor, Rhonda L; Yette, Gabriel A; Lough, Kara M; Ng, Han Leng; Abraham, Lawrence J; Wu, Hui; Kelly, Jennifer A; Glenn, Stuart B; Adler, Adam J; Williams, Adrienne H; Comeau, Mary E; Ziegler, Julie T; Marion, Miranda; Alarcón-Riquelme, Marta E; Alarcón, Graciela S; Anaya, Juan-Manuel; Bae, Sang-Cheol; Kim, Dam; Lee, Hye-Soon; Criswell, Lindsey A; Freedman, Barry I; Gilkeson, Gary S; Guthridge, Joel M; Jacob, Chaim O; James, Judith A; Kamen, Diane L; Merrill, Joan T; Sivils, Kathy Moser; Niewold, Timothy B; Petri, Michelle A; Ramsey-Goldman, Rosalind; Reveille, John D; Scofield, R Hal; Stevens, Anne M; Vilá, Luis M; Vyse, Timothy J; Kaufman, Kenneth M; Harley, John B; Langefeld, Carl D; Gaffney, Patrick M; Brown, Elizabeth E; Edberg, Jeffrey C; Kimberly, Robert P; Ulgiati, Daniela; Tsao, Betty P; Boackle, Susan A

    2016-01-01

    Objectives Systemic lupus erythematosus (SLE; OMIM 152700) is characterised by the production of antibodies to nuclear antigens. We previously identified variants in complement receptor 2 (CR2/CD21) that were associated with decreased risk of SLE. This study aimed to identify the causal variant for this association. Methods Genotyped and imputed genetic variants spanning CR2 were assessed for association with SLE in 15 750 case-control subjects from four ancestral groups. Allele-specific functional effects of associated variants were determined using quantitative real-time PCR, quantitative flow cytometry, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP)-PCR. Results The strongest association signal was detected at rs1876453 in intron 1 of CR2 (pmeta=4.2×10−4, OR 0.85), specifically when subjects were stratified based on the presence of dsDNA autoantibodies (case-control pmeta=7.6×10−7, OR 0.71; case-only pmeta=1.9×10−4, OR 0.75). Although allele-specific effects on B cell CR2 mRNA or protein levels were not identified, levels of complement receptor 1 (CR1/CD35) mRNA and protein were significantly higher on B cells of subjects harbouring the minor allele (p=0.0248 and p=0.0006, respectively). The minor allele altered the formation of several DNA protein complexes by EMSA, including one containing CCCTC-binding factor (CTCF), an effect that was confirmed by ChIP-PCR. Conclusions These data suggest that rs1876453 in CR2 has long-range effects on gene regulation that decrease susceptibility to lupus. Since the minor allele at rs1876453 is preferentially associated with reduced risk of the highly specific dsDNA autoantibodies that are present in preclinical, active and severe lupus, understanding its mechanisms will have important therapeutic implications. PMID:25180293

  9. New Structural Variants of Aeruginosin Produced by the Toxic Bloom Forming Cyanobacterium Nodularia spumigena

    PubMed Central

    Paukku, Eeva; Österholm, Julia; Wahlsten, Matti; Permi, Perttu; Aitio, Olli; Rouhiainen, Leo; Gomez-Saez, Gonzalo V.; Sivonen, Kaarina

    2013-01-01

    Nodularia spumigena is a filamentous diazotrophic cyanobacterium that forms blooms in brackish water bodies. This cyanobacterium produces linear and cyclic peptide protease inhibitors which are thought to be part of a chemical defense against grazers. Here we show that N. spumigena produces structurally novel members of the aeruginosin family of serine protease inhibitors. Extensive chemical analyses including NMR demonstrated that the aeruginosins are comprised of an N-terminal short fatty acid chain, L-Tyr, L-Choi and L-argininal and in some cases pentose sugar. The genome of N. spumigena CCY9414 contains a compact 18-kb aeruginosin gene cluster encoding a peptide synthetase with a reductive release mechanism which offloads the aeruginosins as reactive peptide aldehydes. Analysis of the aeruginosin and spumigin gene clusters revealed two different strategies for the incorporation of N-terminal protecting carboxylic acids. These results demonstrate that strains of N. spumigena produce aeruginosins and spumigins, two families of structurally similar linear peptide aldehydes using separate peptide synthetases. The aeruginosins were chemically diverse and we found 11 structural variants in 16 strains from the Baltic Sea and Australia. Our findings broaden the known structural diversity of the aeruginosin peptide family to include peptides with rare N-terminal short chain (C2–C10) fatty acid moieties. PMID:24040002

  10. Generation and Characterization of Monoclonal Antibodies against a Cyclic Variant of Hepatitis C Virus E2 Epitope 412-422

    PubMed Central

    Sandomenico, Annamaria; Leonardi, Antonio; Berisio, Rita; Sanguigno, Luca; Focà, Giuseppina; Focà, Annalia; Ruggiero, Alessia; Doti, Nunzianna; Muscariello, Livio; Barone, Daniela; Farina, Claudio; Owsianka, Ania; Vitagliano, Luigi

    2016-01-01

    anti-HCV antibodies. MAbs that specifically recognize a cyclic variant of the epitope bind to soluble E2 with a lower affinity than other blocking antibodies and do not neutralize virus. The structure of the complex between one such MAb and the cyclic epitope, together with new structural data showing the linear peptide bound to neutralizing MAbs in extended conformations, suggests that the epitope displays a conformational flexibility that contributes to neutralization escape. Such features can be of major importance for the design of epitope-based anti-HCV vaccines. PMID:26819303

  11. Crystal structure of a 3B3 variant - A broadly neutralizing HIV-1 scFv antibody

    SciTech Connect

    Clark, K. Reed; Walsh, Scott T.R.

    2009-12-10

    We present the crystal structure determination of an anti-HIV-1 gp120 single-chain variable fragment antibody variant, 3B3, at 2.5 {angstrom} resolution. This 3B3 variant was derived from the b12 antibody, using phage display and site-directed mutagenesis of the variable heavy chain (V{sub H}) complementary-determining regions (CDRs). 3B3 exhibits enhanced binding affinity and neutralization activity against several cross-clade primary isolates of HIV-1 by interaction with the recessed CD4-binding site on the gp120 envelope protein. Comparison with the structures of the unbound and bound forms of b12, the 3B3 structure closely resembles these structures with minimal differences with two notable exceptions. First, there is a reorientation of the CDR-H3 of the V{sub H} domain where the primary sequences evolved from b12 to 3B3. The structural changes in CDR-H3 of 3B3, in light of the b12-gp120 complex structure, allow for positioning an additional Trp side chain in the binding interface with gp120. Finally, the second region of structural change involves two peptide bond flips in CDR-L3 of the variable light (VL) domain triggered by a point mutation in CDR-H3 of Q100eY resulting in changes in the intramolecular hydrogen bonding patterning between the VL and VH domains. Thus, the enhanced binding affinities and neutralization capabilities of 3B3 relative to b12 probably result from higher hydrophobic driving potential by burying more aromatic residues at the 3B3-gp120 interface and by indirect stabilization of intramolecular contacts of the core framework residues between the VL and VH domains possibly through more favorable entropic effect through the expulsion of water.

  12. Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies

    PubMed Central

    Parma, Y. R.; Chacana, P. A.; Lucchesi, P. M. A.; Rogé, A.; Granobles Velandia, C. V.; Krüger, A.; Parma, A. E.; Fernández-Miyakawa, M. E.

    2012-01-01

    Enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin producing E. coli (STEC) is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic-uremic syndrome (HUS). Regardless of serotype, Shiga toxins (Stx1 and/or Stx2) are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx) was developed using anti-Stx2B subunit antibodies and its performance was compared with that of the Vero cell assay and a commercial immunoassay kit. Chicken IgY was used as capture antibody and a HRP-conjugated rabbit IgG as the detection antibody. The anti-Stx2B IgY was harvested from eggs laid by hens immunized with a recombinant protein fragment. Several parameters were tested in order to optimize the sandwich ELISA assay, including concentration of antibodies, type and concentration of blocking agent, and incubation temperatures. Supernatants from 42 STEC strains of different serotypes and stx variants, including stx2EDL933, stx2vha, stx2vhb, stx2g, stx1EDL933, and stx1d were tested. All Stx variants were detected by the sandwich ELISA, with a detection limit of 115 ng/ml Stx2. Twenty three strains negative for stx genes, including different bacteria species, showed no activity in Vero cell assay and produced negative results in ELISA, except for two strains. Our results show that anti-Stx2B IgY sandwich ELISA could be used in routine diagnosis as a rapid, specific and economic method for detection of Shiga toxin-producing E. coli. PMID:22919675

  13. Directed evolution of chemotaxis inhibitory protein of Staphylococcus aureus generates biologically functional variants with reduced interaction with human antibodies.

    PubMed

    Gustafsson, Erika; Rosén, Anna; Barchan, Karin; van Kessel, Kok P M; Haraldsson, Karin; Lindman, Stina; Forsberg, Cecilia; Ljung, Lill; Bryder, Karin; Walse, Björn; Haas, Pieter-Jan; van Strijp, Jos A G; Furebring, Christina

    2010-02-01

    Chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS) is a protein that binds and blocks the C5a receptor (C5aR) and formylated peptide receptor, thereby inhibiting the immune cell recruitment associated with inflammation. If CHIPS was less reactive with existing human antibodies, it would be a promising anti-inflammatory drug candidate. Therefore, we applied directed evolution and computational/rational design to the CHIPS gene in order to generate new CHIPS variants displaying lower interaction with human IgG, yet retaining biological function. The optimization was performed in four rounds: one round of random mutagenesis to add diversity into the CHIPS gene and three rounds of DNA recombination by Fragment INduced Diversity (FIND). Every round was screened by phage selection and/or ELISA for decreased interaction with human IgG and retained C5aR binding. The mean binding of human anti-CHIPS IgG decreased with every round of evolution. For further optimization, new amino acid substitutions were introduced by rational design, based on the mutations identified during directed evolution. Finally, seven CHIPS variants with low interaction with human IgG and retained C5aR blocking capacity could be identified. PMID:19959567

  14. Antibody-Mediated Neutralization of the Exotoxin Mycolactone, the Main Virulence Factor Produced by Mycobacterium ulcerans

    PubMed Central

    Gersbach, Philipp; Hug, Melanie N.; Bieri, Raphael; Bomio, Claudio; Li, Jun; Huber, Sylwia; Altmann, Karl-Heinz; Pluschke, Gerd

    2016-01-01

    Background Mycolactone, the macrolide exotoxin produced by Mycobacterium ulcerans, causes extensive tissue destruction by inducing apoptosis of host cells. In this study, we aimed at the production of antibodies that could neutralize the cytotoxic activities of mycolactone. Methodology/Principal Findings Using the B cell hybridoma technology, we generated a series of monoclonal antibodies with specificity for mycolactone from spleen cells of mice immunized with the protein conjugate of a truncated synthetic mycolactone derivative. L929 fibroblasts were used as a model system to investigate whether these antibodies can inhibit the biological effects of mycolactone. By measuring the metabolic activity of the fibroblasts, we found that anti-mycolactone mAbs can completely neutralize the cytotoxic activity of mycolactone. Conclusions/Significance The toxin neutralizing capacity of anti-mycolactone mAbs supports the concept of evaluating the macrolide toxin as vaccine target. PMID:27351976

  15. Reaginic antibodies from horses with recurrent airway obstruction produce mast cell stimulation.

    PubMed

    Moran, G; Folch, H; Henriquez, C; Ortloff, A; Barria, M

    2012-12-01

    Reaginic antibodies (IgE and some IgG subclasses) and mast cells play important roles in the induction of type I immediate hypersensitivity reactions. These antibodies bind through their Fc fragment to high affinity receptors (FcεRI) present in the membrane of mast cells and basophils. The cross-linking of the receptor initiates a coordinated sequence of biochemical and morphological events that results in exocytosis of secretory granules containing pre-formed inflammatory mediators, secretion of newly formed lipid mediators, and secretion of cytokines. Previously, several studies have investigated the role of reaginic antibodies in the pathogenesis of Recurrent Airway Obstruction (RAO). However, whereas the immunological aspects of RAO have been extensively studied, the precise sequence of events involved in the pathogenesis remains not completely understood, and the role of IgE in this disease remains controversial. Therefore, in this study, several bioassays were conducted to determine whether reaginic antibodies from RAO-affected horses have the ability to activate mast cells. These bioassays involved measuring degranulation of rat peritoneal mast cells, activation of NF-κB and morphological changes in basophilic leukemia cells (RBL-2H3) following incubation with horse serum from RAO-affected horses that were sensitive and insensitive to Aspergillus fumigatus (A. fumigatus) or from unaffected horses. Our results show that reaginic antibodies from horses sensitive to A. fumigatus were able to degranulate rat peritoneal mast cells. In additon, there was an increase in the activity of the transcription factor NF-κB in RBL-2H3 cells, and morphological changes were observed in these cells once cross-linking was produced. These findings were not found in horses not sensitive to A. fumigatus and healthy horses. These bioassays demonstrate the ability of reaginic antibodies to stimulate mast cells and indicate that these antibodies could be involved in the

  16. Characterization of C-strain “Riems” TAV-epitope escape variants obtained through selective antibody pressure in cell culture

    PubMed Central

    2012-01-01

    Classical swine fever virus (CSFV) C-strain “Riems” escape variants generated under selective antibody pressure with monoclonal antibodies and a peptide-specific antiserum in cell culture were investigated. Candidates with up to three amino acid exchanges in the immunodominant and highly conserved linear TAV-epitope of the E2-glycoprotein, and additional mutations in the envelope proteins ERNS and E1, were characterized both in vitro and in vivo. It was further demonstrated, that intramuscular immunization of weaner pigs with variants selected after a series of passages elicited full protection against lethal CSFV challenge infection. These novel CSFV C-strain variants with exchanges in the TAV-epitope present potential marker vaccine candidates. The DIVA (differentiating infected from vaccinated animals) principle was tested for those variants using commercially available E2 antibody detection ELISA. Moreover, direct virus differentiation is possible using a real-time RT-PCR system specific for the new C-strain virus escape variants or using differential immunofluorescence staining. PMID:22515281

  17. Heterosubtypic neutralizing antibodies are produced by individuals immunized with a seasonal influenza vaccine

    PubMed Central

    Corti, Davide; Suguitan, Amorsolo L.; Pinna, Debora; Silacci, Chiara; Fernandez-Rodriguez, Blanca M.; Vanzetta, Fabrizia; Santos, Celia; Luke, Catherine J.; Torres-Velez, Fernando J.; Temperton, Nigel J.; Weiss, Robin A.; Sallusto, Federica; Subbarao, Kanta; Lanzavecchia, Antonio

    2010-01-01

    The target of neutralizing antibodies that protect against influenza virus infection is the viral protein HA. Genetic and antigenic variation in HA has been used to classify influenza viruses into subtypes (H1–H16). The neutralizing antibody response to influenza virus is thought to be specific for a few antigenically related isolates within a given subtype. However, while heterosubtypic antibodies capable of neutralizing multiple influenza virus subtypes have been recently isolated from phage display libraries, it is not known whether such antibodies are produced in the course of an immune response to influenza virus infection or vaccine. Here we report that, following vaccination with seasonal influenza vaccine containing H1 and H3 influenza virus subtypes, some individuals produce antibodies that cross-react with H5 HA. By immortalizing IgG-expressing B cells from 4 individuals, we isolated 20 heterosubtypic mAbs that bound and neutralized viruses belonging to several HA subtypes (H1, H2, H5, H6, and H9), including the pandemic A/California/07/09 H1N1 isolate. The mAbs used different VH genes and carried a high frequency of somatic mutations. With the exception of a mAb that bound to the HA globular head, all heterosubtypic mAbs bound to acid-sensitive epitopes in the HA stem region. Four mAbs were evaluated in vivo and protected mice from challenge with influenza viruses representative of different subtypes. These findings reveal that seasonal influenza vaccination can induce polyclonal heterosubtypic neutralizing antibodies that cross-react with the swine-origin pandemic H1N1 influenza virus and with the highly pathogenic H5N1 virus. PMID:20389023

  18. Activation of clones producing self-reactive antibodies by foreign antigen and antiidiotype antibody carrying the internal image of the antigen.

    PubMed Central

    Bailey, N C; Fidanza, V; Mayer, R; Mazza, G; Fougereau, M; Bona, C

    1989-01-01

    Because we found in previous work that a high fraction of antibodies exhibiting various specificities bound to glutamic acid 50-tyrosine50 homopolymer (GT) and expressed pGAT cross-reactive idiotype (IdX), we studied the activation of clones producing multireactive antibodies in 1-mo-old MRL/lpr and C3H/HeJ mice bearing VHJ haplotype. The activation of such clones was studied after mice were immunized with GT in CFA, HP20 (an anti-Id MAb carrying the internal image of GT in the D region), and a synthetic peptide corresponding to the D segment of HP20. Our results indicate that immunized mice produced both GT- and self-reactive antibodies. Study of the immunochemical properties of MAb showed that they exhibit multispecific properties and bind with similar-affinity constants to GT or self-antigens such as DNA, Smith antigen (Sm), and IgG2a. An important fraction of antibodies obtained from MRL/lpr mice immunized with HP20 expressed pGAT IdX and some of these antibodies share IdX expressed on anti-DNA, Sm, and rheumatoid factor (RFs) antibodies. The hybridomas producing multispecific autoantibodies use heavy-chain- (VH) and light-chain-variable region (VK) genes from various V gene families, suggesting that they do not derive from the pool of GAT precursors. Sequencing of VH and VK genes of two antibodies show that they can use closely related VHJ558, unmutated VK1, or different VK genes than those used by anti-GT antibodies. Our data demonstrate that clones producing antibodies binding to GT and self-antigens with similar-affinity constants can be activated by foreign or anti-Id antibodies carrying the internal image of the antigen or even by a synthetic peptide corresponding to the D segment of anti-Id antibodies. Images PMID:2760212

  19. Clinical Associations of Biallelic and Monoallelic TNFRSF13B Variants in Italian Primary Antibody Deficiency Syndromes

    PubMed Central

    Pulvirenti, Federica; Zuntini, Roberta; Milito, Cinzia; Specchia, Fernando; Spadaro, Giuseppe; Danieli, Maria Giovanna; Pession, Andrea; Quinti, Isabella; Ferrari, Simona

    2016-01-01

    We assessed the prevalence of TNFRSF13B mutations and the clinical correlates in an Italian cohort of 189 CVID, 67 IgAD patients, and 330 healthy controls to substantiate the role of TACI genetic testing in diagnostic workup. We found that 11% of CVID and 13% of IgAD carried at least one mutated TNFRSF13B allele. Seven per cent of CVID had monoallelic-mutations and 4% had biallelic-mutations. The frequency of C104R monoallelic-mutations was not higher than that found in healthy controls. Biallelic-mutations were exclusively found in CVID. CVID patients carrying monoallelic-mutations had an increased prevalence of lymphadenopathy, granulomata, and autoimmune cytopenias. CVID carrying biallelic-mutations had a low prevalence of autoimmunity in comparison with TACI wild-type CVID. Moreover, biallelic-mutated CVID had higher frequency of switched memory B-cells and higher IgM and IgA antibodies to polysaccharide antigens than TACI wild-type and monoallelic-mutated CVID. TACI-mutated IgAD patients had only monoallelic-mutations and did not display clinical difference from IgAD wild-type patients. In conclusion, TNFRSF13B genetic screening of antibody deficiencies may allow the identification of mutational patterns. However, as with counseling for risk assessment, geneticists should be aware that the interpretation of genetic testing for TACI mutations is difficult and the potential impact on clinical management is still limited. PMID:27123465

  20. Clinical Associations of Biallelic and Monoallelic TNFRSF13B Variants in Italian Primary Antibody Deficiency Syndromes.

    PubMed

    Pulvirenti, Federica; Zuntini, Roberta; Milito, Cinzia; Specchia, Fernando; Spadaro, Giuseppe; Danieli, Maria Giovanna; Pession, Andrea; Quinti, Isabella; Ferrari, Simona

    2016-01-01

    We assessed the prevalence of TNFRSF13B mutations and the clinical correlates in an Italian cohort of 189 CVID, 67 IgAD patients, and 330 healthy controls to substantiate the role of TACI genetic testing in diagnostic workup. We found that 11% of CVID and 13% of IgAD carried at least one mutated TNFRSF13B allele. Seven per cent of CVID had monoallelic-mutations and 4% had biallelic-mutations. The frequency of C104R monoallelic-mutations was not higher than that found in healthy controls. Biallelic-mutations were exclusively found in CVID. CVID patients carrying monoallelic-mutations had an increased prevalence of lymphadenopathy, granulomata, and autoimmune cytopenias. CVID carrying biallelic-mutations had a low prevalence of autoimmunity in comparison with TACI wild-type CVID. Moreover, biallelic-mutated CVID had higher frequency of switched memory B-cells and higher IgM and IgA antibodies to polysaccharide antigens than TACI wild-type and monoallelic-mutated CVID. TACI-mutated IgAD patients had only monoallelic-mutations and did not display clinical difference from IgAD wild-type patients. In conclusion, TNFRSF13B genetic screening of antibody deficiencies may allow the identification of mutational patterns. However, as with counseling for risk assessment, geneticists should be aware that the interpretation of genetic testing for TACI mutations is difficult and the potential impact on clinical management is still limited. PMID:27123465

  1. Intermediate filament proteins in classic and variant types of small cell lung carcinoma cell lines: a biochemical and immunochemical analysis using a panel of monoclonal and polyclonal antibodies.

    PubMed

    Broers, J L; Carney, D N; Klein Rot, M; Schaart, G; Lane, E B; Vooijs, G P; Ramaekers, F C

    1986-07-01

    The intermediate filament protein (IFP) characteristics of a panel of lung cancer cell lines including adenocarcinoma (two cell lines) and small cell lung cancer (SCLC, three classic and three variant cell lines) were examined using one- and two-dimensional gel electrophoretic techniques, immunocytochemical techniques and immunoblotting assays. A panel of 28 monoclonal and polyclonal antibodies to the five different types of IFP were used. The results of our studies indicate that these human lung adenocarcinoma, classic SCLC and variant SCLC cell lines can be differentiated on the basis of their pattern of IFP. The main conclusions from this study can be summarized as follows. The two adenocarcinoma cell lines contain cytokeratins 7, 8, 18, and sometimes 19, next to vimentin intermediate filament (IF). The three classic-type SCLC cell lines contain only cytokeratin IFs but not vimentin IF or neurofilaments (NFs). Cytokeratin polypeptides 7, 8, 18 and 19 could be detected. All three variant-type SCLC cell lines do not contain detectable amounts of cytokeratins. In contrast, two out of three variant SCLC cell lines contain neurofilament proteins. All three variant-type SCLC cell lines contain vimentin IF. Using immunoblotting assays with monoclonal and polyclonal antibodies to defined NF proteins the presence of the 68 X 10(3) Mr and the 160 X 10(3) Mr NF polypeptide could be demonstrated in two variant SCLC cell lines. As patients with SCLC-variant phenotype have a poorer prognosis after cytotoxic therapy than patients with 'pure' SCLC, the use of antibodies to IFP in staining fresh lung tumours, especially anaplastic ones, may differentiate the two subtypes of SCLC. Such a distinction would have a major impact on therapy selections and may be of prognostic importance. PMID:2433295

  2. Importance of polar solvation for cross-reactivity of antibody and its variants with steroids.

    PubMed

    Kar, Parimal; Lipowsky, Reinhard; Knecht, Volker

    2011-06-16

    Understanding the factors determining the binding of ligands to receptors in detail is essential for rational drug design. Here, the free energies of binding of the steroids progesterone (PRG) and 5β-androstane-3,17-dione (5AD) to the Diels-Alderase antibody 1E9, as well as the Leu(H47)Trp/Arg(H100)Trp 1E9 double mutant (1E9dm) and the corresponding single mutants, have been estimated and decomposed using the molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) method. Also the difference in binding free energies between the PRG-1E9dm complex and the complex of PRG with the antiprogesterone antibody DB3 have been evaluated and decomposed. The steroids bind less strongly to 1E9 than to DB3, but the mutations tend to improve the steroid affinity, in quantitative agreement with experimental data. Although the complexes formed by PRG or 5AD with 1E9dm and by PRG with DB3 have similar affinity, the binding mechanisms are different. Reduced van der Waals interactions as observed for 5AD-1E9dm versus PRG-1E9dm or for PRG-1E9dm versus PRG-DB3 are energetically compensated by an increased solvation of polar groups, partly contrasting previous conclusions based on structural inspection. Our study illustrates that deducing binding mechanisms from structural models alone can be misleading. Therefore, taking into account solvation effects as in MM-PBSA calculations is essential to elucidate molecular recognition. PMID:21595427

  3. Trans-splicing as a novel method to rapidly produce antibody fusion proteins

    SciTech Connect

    Iwasaki, Ryohei; Kiuchi, Hiroki; Ihara, Masaki; Mori, Toshihiro; Kawakami, Masayuki; Ueda, Hiroshi

    2009-07-03

    To cultivate the use of trans-splicing as a novel means to rapidly express various antibody fusion proteins, we tried to express antibody-reporter enzyme fusions in a COS-1 co-transfection model. When a vector designed to induce trans-splicing with IgH pre-mRNA was co-transfected with a vector encoding the mouse IgM locus, the expression of V{sub H}-secreted human placental alkaline phosphatase (SEAP) as well as Fab-SEAP were successfully expressed both in mRNA and protein levels. Especially, the vectors encoding complementary sequence to S{mu} as a binding domain was accurate and efficient, producing trans-spliced mRNA of up to 2% of cis-spliced one. Since S{mu} sequence should exist in every IgH pre-mRNA, our finding will lead to the rapid production and analysis of various antibody-enzyme fusions suitable for enzyme-linked immunosorbent assay (ELISA) or antibody-dependent enzyme prodrug therapy (ADEPT).

  4. B cells produce pathogenic antibodies and impair recovery after spinal cord injury in mice

    PubMed Central

    Ankeny, Daniel P.; Guan, Zhen; Popovich, Phillip G.

    2009-01-01

    Traumatic injury to the mammalian spinal cord activates B cells, which culminates in the synthesis of autoantibodies. The functional significance of this immune response is unclear. Here, we show that locomotor recovery was improved and lesion pathology was reduced after spinal cord injury (SCI) in mice lacking B cells. After SCI, antibody-secreting B cells and Igs were present in the cerebrospinal fluid and/or injured spinal cord of WT mice but not mice lacking B cells. In mice with normal B cell function, large deposits of antibody and complement component 1q (C1q) accumulated at sites of axon pathology and demyelination. Antibodies produced after SCI caused pathology, in part by activating intraspinal complement and cells bearing Fc receptors. These data indicate that B cells, through the production of antibodies, affect pathology in SCI. One or more components of this pathologic immune response could be considered as novel therapeutic targets for minimizing tissue injury and/or promoting repair after SCI. PMID:19770513

  5. The development of a monoclonal antibody recognizing the Drosophila melanogaster phosphorylated histone H2A variant (γ-H2AV).

    PubMed

    Lake, Cathleen M; Holsclaw, Julie Korda; Bellendir, Stephanie P; Sekelsky, Jeff; Hawley, R Scott

    2013-09-01

    The recognition of DNA double-strand breaks (DSBs) using a phospho-specific antibody to the histone 2A variant has become the gold standard assay for DNA damage detection. Here we report on the development of the first monoclonal antibody to the phospho-specific form of Drosophila H2AV and characterize the specificity of this antibody to programmed DSBs in oocytes and rereplication sites in endocycling cells by immunofluorescence assays and to DSBs resulting from irradiation in both cell culture and whole tissue by Western blot assays. These studies show that the antibody derived in the study is highly specific for this modification that occurs at DSB sites, and therefore will be a new useful tool within the Drosophila community for the study of DNA damage response, DSB repair, meiotic recombination and chemical agents that cause DNA damage. PMID:23833215

  6. Hepatitis C Virus Hypervariable Region 1 Variants Presented on Hepatitis B Virus Capsid-Like Particles Induce Cross-Neutralizing Antibodies

    PubMed Central

    Bankwitz, Dorothea; Osburn, William; Viazov, Sergei; Brovko, Olena; Zekri, Abdel-Rahman; Khudyakov, Yury; Nassal, Michael; Pumpens, Paul; Pietschmann, Thomas; Timm, Jörg; Roggendorf, Michael; Walker, Andreas

    2014-01-01

    Hepatitis C virus (HCV) infection is still a serious global health burden. Despite improved therapeutic options, a preventative vaccine would be desirable especially in undeveloped countries. Traditionally, highly conserved epitopes are targets for antibody-based prophylactic vaccines. In HCV-infected patients, however, neutralizing antibodies are primarily directed against hypervariable region I (HVRI) in the envelope protein E2. HVRI is the most variable region of HCV, and this heterogeneity contributes to viral persistence and has thus far prevented the development of an effective HVRI-based vaccine. The primary goal of an antibody-based HCV vaccine should therefore be the induction of cross-reactive HVRI antibodies. In this study we approached this problem by presenting selected cross-reactive HVRI variants in a highly symmetric repeated array on capsid-like particles (CLPs). SplitCore CLPs, a novel particulate antigen presentation system derived from the HBV core protein, were used to deliberately manipulate the orientation of HVRI and therefore enable the presentation of conserved parts of HVRI. These HVRI-CLPs induced high titers of cross-reactive antibodies, including neutralizing antibodies. The combination of only four HVRI CLPs was sufficient to induce antibodies cross-reactive with 81 of 326 (24.8%) naturally occurring HVRI peptides. Most importantly, HVRI CLPs with AS03 as an adjuvant induced antibodies with a 10-fold increase in neutralizing capability. These antibodies were able to neutralize infectious HCVcc isolates and 4 of 19 (21%) patient-derived HCVpp isolates. Taken together, these results demonstrate that the induction of at least partially cross-neutralizing antibodies is possible. This approach might be useful for the development of a prophylactic HCV vaccine and should also be adaptable to other highly variable viruses. PMID:25014219

  7. Effect of temperature shift on levels of acidic charge variants in IgG monoclonal antibodies in Chinese hamster ovary cell culture.

    PubMed

    Kishishita, Shohei; Nishikawa, Tomoko; Shinoda, Yasuharu; Nagashima, Hiroaki; Okamoto, Hiroshi; Takuma, Shinya; Aoyagi, Hideki

    2015-06-01

    During the production of therapeutic monoclonal antibodies (mAbs), not only enhancement of mAb productivity but also control of quality attributes is critical. Charge variants, which are among the most important quality attributes, can substantially affect the in vitro and in vivo properties of mAbs. During process development for the production of mAbs in a Chinese hamster ovary cell line, we have observed that an improvement in mAb titer is accompanied by an increase in the content of acidic charge variants. Here, to help maintain comparability among mAbs, we aimed to identify the process parameters that controlled the content of acidic charge variants. First, we used a Plackett-Burman design to identify the effect of selected process parameters on the acidic charge variant content. Eight process parameters were selected by using a failure modes and effects analysis. Among these, temperature shift was identified from the Plackett-Burman design as the factor most influencing the acidic charge variant content. We then investigated in more detail the effects of shift temperature and temperature shift timing on this content. The content decreased with a shift to a lower temperature and with earlier timing of this temperature shift. Our observations suggest that Plackett-Burman designs are advantageous for preliminary screening of bioprocess parameters. We report here for the first time that temperature downshift is beneficial for effective control of the acidic peak variant content. PMID:25466646

  8. IMMUNODOMINANT EPITOPE AND PROPERTIES OF PYROGLUTAMATE-MODIFIED Aβ-SPECIFIC ANTIBODIES PRODUCED IN RABBITS

    PubMed Central

    Acero, G.; Manoutcharian, K.; Vasilevko, V.; Munguia, M.E.; Govezensky, T.; Coronas, G.; Luz-Madrigal, A.; Cribbs, DH.; Gevorkian, G.

    2009-01-01

    N-truncated and N-modified forms of amyloid beta (Aß) peptide are found in diffused and dense core plaques in Alzheimer’s disease (AD) and Down’s syndrome patients as well as transgenic mouse models of AD. Although the pathological significance of these shortened forms Aβ is not completely understood, previous studies have demonstrated that these peptides are significantly more resistant to degradation, aggregate more rapidly in vitro and exhibit similar or, in some cases, increased toxicity in hippocampal neuronal cultures compared to the full-length peptides. In the present study we further investigated the mechanisms of toxicity of one of the most abundant Ntruncated/modified Aβ peptide bearing amino-terminal pyroglutamate at position 3 (AβN3(pE)). We demonstrated that AβN3(pE) oligomers induce phosphatidyl serine externalization and membrane damage in SH-SY5Y cells. Also, we produced AβN3(pE)-specific polyclonal antibodies in rabbit and identified an immunodominant epitope recognized by anti-AβN3(pE) antibodies. Our results are important for developing new immunotherapeutic compounds specifically targeting AβN3(pE) aggregates since the most commonly used immunogens in the majority of vaccines for AD have been shown to induce antibodies that recognize the N-terminal immunodominant epitope (EFRH) of the full length Aβ, which is absent in N-amino truncated peptides. PMID:19545911

  9. Immunodominant epitope and properties of pyroglutamate-modified Abeta-specific antibodies produced in rabbits.

    PubMed

    Acero, G; Manoutcharian, K; Vasilevko, V; Munguia, M E; Govezensky, T; Coronas, G; Luz-Madrigal, A; Cribbs, D H; Gevorkian, G

    2009-08-18

    N-truncated and N-modified forms of amyloid beta (Abeta) peptide are found in diffused and dense core plaques in Alzheimer's disease (AD) and Down's syndrome patients as well as transgenic mouse models of AD. Although the pathological significance of these shortened forms Abeta is not completely understood, previous studies have demonstrated that these peptides are significantly more resistant to degradation, aggregate more rapidly in vitro and exhibit similar or, in some cases, increased toxicity in hippocampal neuronal cultures compared to the full length peptides. In the present study we further investigated the mechanisms of toxicity of one of the most abundant N-truncated/modified Abeta peptide bearing amino-terminal pyroglutamate at position 3 (AbetaN3(pE)). We demonstrated that AbetaN3(pE) oligomers induce phosphatidyl serine externalization and membrane damage in SH-SY5Y cells. Also, we produced AbetaN3(pE)-specific polyclonal antibodies in rabbit and identified an immunodominant epitope recognized by anti-AbetaN3(pE) antibodies. Our results are important for developing new immunotherapeutic compounds specifically targeting AbetaN3(pE) aggregates since the most commonly used immunogens in the majority of vaccines for AD have been shown to induce antibodies that recognize the N-terminal immunodominant epitope (EFRH) of the full length Abeta, which is absent in N-amino truncated peptides. PMID:19545911

  10. Mutation Detection in an Antibody-Producing Chinese Hamster Ovary Cell Line by Targeted RNA Sequencing

    PubMed Central

    Zhang, Siyan; Hughes, Jason D.; Murgolo, Nicholas; Levitan, Diane; Chen, Janice; Liu, Zhong

    2016-01-01

    Chinese hamster ovary (CHO) cells have been used widely in the pharmaceutical industry for production of biological therapeutics including monoclonal antibodies (mAb). The integrity of the gene of interest and the accuracy of the relay of genetic information impact product quality and patient safety. Here we employed next-generation sequencing, particularly RNA-seq, and developed a method to systematically analyze the mutation rate of the mRNA of CHO cell lines producing a mAb. The effect of an extended culturing period to mimic the scale of cell expansion in a manufacturing process and varying selection pressure in the cell culture were also closely examined. PMID:27088091

  11. Feasibility studies of using the Catfish Immune System to produce monoclonal antibodies

    SciTech Connect

    Poston, T.M.

    1987-03-01

    The objective of these studies was to determine the feasibility of using a teleost cell line to produce monoclonal antibodies. Studies were undertaken to demonstrate the production of a polyclonal response of channel catfish (Icatalurus punctatus) challenged with mycotoxins coupled to a protein carrier. Companion studies were also performed to induce a permanent cell line with catfish lymphocytes. Attempts to demonstrate a polyclonal response to haptenized mycotoxins were inconclusive. Tests to induce an immortal, permanent cell line with benzene and x-ray irradiated cells were also inconclusive. 3 refs., 13 tabs.

  12. Novel Exons and Splice Variants in the Human Antibody Heavy Chain Identified by Single Cell and Single Molecule Sequencing

    PubMed Central

    Vollmers, Christopher; Penland, Lolita; Kanbar, Jad N.; Quake, Stephen R.

    2015-01-01

    Antibody heavy chains contain a variable and a constant region. The constant region of the antibody heavy chain is encoded by multiple groups of exons which define the isotype and therefore many functional characteristics of the antibody. We performed both single B cell RNAseq and long read single molecule sequencing of antibody heavy chain transcripts and were able to identify novel exons for IGHA1 and IGHA2 as well as novel isoforms for IGHM antibody heavy chain. PMID:25611855

  13. Enhanced sialylation of a human chimeric IgG1 variant produced in human and rodent cell lines.

    PubMed

    Mimura, Yusuke; Kelly, Ronan M; Unwin, Louise; Albrecht, Simone; Jefferis, Roy; Goodall, Margaret; Mizukami, Yoichi; Mimura-Kimura, Yuka; Matsumoto, Tsuneo; Ueoka, Hiroshi; Rudd, Pauline M

    2016-01-01

    Glycosylation of the IgG-Fc is essential for optimal binding and activation of Fcγ receptors and the C1q component of complement. However, it has been reported that the effector functions are down-regulated when the Fc glycans terminate in sialic acid residues and that sialylated IgG mediates anti-inflammatory effects of intravenous immunoglobulin (IVIG). Although recombinant IgG is hypo-sialylated, Fc sialylation is shown to be markedly increased when a mouse/human chimeric IgG3 Phe243Ala (F243A) variant is expressed in Chinese hamster ovary (CHO)-K1 cells. Here we investigate whether sialylation is increased in IgG1 F243A when expressed in CHO-K1, mouse myeloma J558L and human embryonic kidney (HEK) 293. Although the sialylation level was 2-5% for IgG1 wild type (WT), it was increased to 31%, 10% and 33% for the variant from CHO-K1, J558L and HEK293 cells, respectively. Interestingly, an increased addition of bisecting GlcNAc and α(1-3)-galactose residues to the Fc glycan was observed for HEK293-derived and J558L-derived IgG1 F243A, respectively. Fucosylation of HEK293-derived IgG1 F243A was maintained despite increased bisecting GlcNAc content. Although sialic acid and bisecting GlcNAc residues are reported to have an opposing effect on antibody-dependent cellular cytotoxicity (ADCC), IgG1 F243A showed 7 times lower ADCC activities than IgG1 WT, irrespective of bisecting GlcNAc residue. Thus, highly sialylated, human cell-derived IgG1 F243A with lowered ADCC activity may be of interest for the development of therapeutic antibodies with anti-inflammatory properties as an alternative to IVIG. PMID:26627984

  14. New Monoclonal Antibodies against a Novel Subtype of Shiga Toxin 1 Produced by Enterobacter cloacae and Their Use in Analysis of Human Serum

    PubMed Central

    Skinner, Craig; Patfield, Stephanie; Khalil, Rowaida; Kong, Qiulian

    2016-01-01

    ABSTRACT Shiga toxin (Stx) is a major virulence factor of several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges for the clinical diagnosis of infections caused by Stx-producing organisms. Here, we report the development of four new monoclonal antibodies (MAbs) against Stx1e, a novel subtype of Stx1 that was produced by an Enterobacter cloacae strain and had limited reactivity with existing anti-Stx1 antibodies. Western blot analysis indicates that these MAbs were Stx1 specific, bound to the A subunit, and had distinct preferences for subtypes of Stx1. Of the four MAbs, Stx1e-2 was capable of partially neutralizing cytotoxicities derived from Stx1e in Vero cells. Enzyme-linked immunosorbent assays assembled with these high-affinity MAbs detected Stx1e at concentrations as low as 4.8 pg/ml in phosphate-buffered saline and 53.6 pg/ml in spiked human serum samples and were also capable of distinguishing Stx1e-producing strains in enriched cultures. These assays may therefore have clinical value in diagnosing Stx1e-producing bacterial infection. Additionally, characteristics of Stx1e, such as the origin of stx1e genes, conditions for toxin expression, receptor binding, and cytotoxicity, were investigated with the new antibodies developed in this study. This information should be useful for further understanding the clinical significance and prevalence of Stx1e-harboring E. cloacae and other organisms. IMPORTANCE Stxs are among the most clinically important virulence factors of Shigella and enterohemorrhagic Escherichia coli. There are many varieties of Stx, and although Stx1a and Stx2a are the most common and widely distributed types of Stx, new variants of Stx are continually emerging. These new variants of Stx can be challenging to detect, since most Stx detection kits are optimized for the detection of Stx1a and Stx2a. Stx1e, recently

  15. Clinical development of plant-produced recombinant pharmaceuticals: vaccines, antibodies and beyond.

    PubMed

    Yusibov, Vidadi; Streatfield, Stephen J; Kushnir, Natasha

    2011-03-01

    In the last few years, plants have become an increasingly attractive platform for recombinant protein production. This builds on two decades of research, starting with transgenic approaches to develop oral vaccines in which antigens or therapeutics can be delivered in processed plant biomass, and progressing to transient expression approaches whereby high yields of purified targets are administered parenterally. The advantages of plant-based expression systems include high scalability, low upstream costs, biocontainment, lack of human or animal pathogens, and ability to produce target proteins with desired structures and biological functions. Using transgenic and transient expression in whole plants or plant cell culture, a variety of recombinant subunit vaccine candidates, therapeutic proteins, including monoclonal antibodies, and dietary proteins have been produced. Some of these products have been tested in early phase clinical trials, and show safety and efficacy. Among those are mucosal vaccines for diarrheal diseases, hepatitis B and rabies; injectable vaccines for non-Hodgkin's lymphoma, H1N1 and H5N1 strains of influenza A virus, and Newcastle disease in poultry; and topical antibodies for the treatment of dental caries and HIV. As lead plant-based products have entered clinical trials, there has been increased emphasis on manufacturing under current Good Manufacturing Practice (cGMP) guidelines, and the preparation and presentation to the relevant government agencies of regulatory packages. PMID:21346417

  16. Bioengineering of a Nisin A-producing Lactococcus lactis to create isogenic strains producing the natural variants Nisin F, Q and Z.

    PubMed

    Piper, Clare; Hill, Colin; Cotter, Paul D; Ross, R Paul

    2011-05-01

    Nisin is the prototypical example of the lantibiotic family of antimicrobial peptides and has been employed as a food preservative for over half a century. It has also attracted attention due to its potency against a number of multidrug-resistant clinical pathogens. Nisin A is the originally isolated form of Nisin and a further five natural variants have been described which differ by up to 10 amino acids (of 34 in total in Nisin A). Nisins A, Z, F and Q are produced by Lactococcus lactis, while Nisins U and U2 are produced by Streptococcus sp. In this study we bioengineered the nisA gene of a Nisin A producer to generate genes encoding Nisins Z, F, Q, U and U2. We determined that while active Nisin Z, F and Q can be produced against this genetic background, active forms of Nisin U and U2 are not generated. Minimum inhibitory concentration studies with Nisin A, Z, F and Q variants against a series of different clinically significant pathogens establish differences in specific activities against selected targets. Nisin F was most impressive, being the most active, or one of the most active, against the MRSA strain ST 525, EC 676, EC 725, VISA 22900, VISA 22781, hVISA 35197, Staphylococcus aureus 8325-4 and L. lactis HP. Nisin Z was most active against ST 299, hVISA 32683 and, together with Nisin F, HP but had contrastingly poor activity against ST 525, EC 676 and 8325-4. Nisin F, Q and A exhibited similar potency against VISA 22900. This was the only target against which Nisin Q and Nisin A were among the most active variants. PMID:21375711

  17. Metabolic analysis of antibody producing Chinese hamster ovary cell culture under different stresses conditions.

    PubMed

    Badsha, Md Bahadur; Kurata, Hiroyuki; Onitsuka, Masayoshi; Oga, Takushi; Omasa, Takeshi

    2016-07-01

    Chinese hamster ovary (CHO) cells are commonly used as the host cell lines concerning their ability to produce therapeutic proteins with complex post-translational modifications. In this study, we have investigated the time course extra- and intracellular metabolome data of the CHO-K1 cell line, under a control and stress conditions. The addition of NaCl and trehalose greatly suppressed cell growth, where the maximum viable cell density of NaCl and trehalose cultures were 2.2-fold and 2.8-fold less than that of a control culture. Contrariwise, the antibody production of both the NaCl and trehalose cultures was sustained for a longer time to surpass that of the control culture. The NaCl and trehalose cultures showed relatively similar dynamics of cell growth, antibody production, and substrate/product concentrations, while they indicated different dynamics from the control culture. The principal component analysis of extra- and intracellular metabolome dynamics indicated that their dynamic behaviors were consistent with biological functions. The qualitative pattern matching classification and hierarchical clustering analyses for the intracellular metabolome identified the metabolite clusters whose dynamic behaviors depend on NaCl and trehalose. The volcano plot revealed several reporter metabolites whose dynamics greatly change between in the NaCl and trehalose cultures. The elastic net identified some critical, intracellular metabolites that are distinct between the NaCl and trehalose. While a relatively small number of intracellular metabolites related to the cell growth, glucose, glutamine, lactate and ammonium ion concentrations, the mechanism of antibody production was suggested to be very complicated or not to be explained by elastic net regression analysis. PMID:26803706

  18. In situ gastrointestinal protection against anthrax edema toxin by single-chain antibody fragment producing lactobacilli

    PubMed Central

    2011-01-01

    Background Anthrax is caused by the bacterium Bacillus anthracis and is regarded as one of the most prominent bioterrorism threats. Anthrax toxicity is induced by the tripartite toxin complex, composed of the receptor-binding anthrax protective antigen and the two enzymatic subunits, lethal factor and edema factor. Recombinant lactobacilli have previously been used to deliver antibody fragments directed against surface epitopes of a variety of pathogens, including Streptococcus mutans, Porphyromonas gingivalis, and rotavirus. Here, we addressed whether or not anthrax toxins could be targeted and neutralised in the gastrointestinal tract by lactobacilli producing recombinant antibody fragments as a model system for toxin neutralisation in the gastrointestinal lumen. Results The neutralising anti-PA scFv, 1H, was expressed in L. paracasei as a secreted protein, a cell wall-anchored protein or both secreted and wall-anchored protein. Cell wall display on lactobacilli and PA binding of the anchored constructs was confirmed by flow cytometry analysis. Binding of secreted or attached scFv produced by lactobacilli to PA were verified by ELISA. Both construct were able to protect macrophages in an in vitro cytotoxicity assay. Finally, lactobacilli producing the cell wall attached scFv were able to neutralise the activity of anthrax edema toxin in the GI tract of mice, in vivo. Conclusion We have developed lactobacilli expressing a neutralising scFv fragment against the PA antigen of the anthrax toxin, which can provide protection against anthrax toxins both in vitro and in vivo. Utilising engineered lactobacilli therapeutically for neutralising toxins in the gastrointestinal tract can potential be expanded to provide protection against a range of additional gastrointestinal pathogens. The ability of lactobacilli to colonise the gastrointestinal tract may allow the system to be used both prophylactically and therapeutically. PMID:22185669

  19. Characterization of anti-CD20 monoclonal antibody produced by transgenic silkworms (Bombyx mori)

    PubMed Central

    Tada, Minoru; Tatematsu, Ken-Ichiro; Ishii-Watabe, Akiko; Harazono, Akira; Takakura, Daisuke; Hashii, Noritaka; Sezutsu, Hideki; Kawasaki, Nana

    2015-01-01

    In response to the successful use of monoclonal antibodies (mAbs) in the treatment of various diseases, systems for expressing recombinant mAbs using transgenic animals or plants have been widely developed. The silkworm (Bombyx mori) is a highly domesticated insect that has recently been used for the production of recombinant proteins. Because of their cost-effective breeding and relatively easy production scale-up, transgenic silkworms show great promise as a novel production system for mAbs. In this study, we established a transgenic silkworm stably expressing a human-mouse chimeric anti-CD20 mAb having the same amino acid sequence as rituximab, and compared its characteristics with rituximab produced by Chinese hamster ovary (CHO) cells (MabThera®). The anti-CD20 mAb produced in the transgenic silkworm showed a similar antigen-binding property, but stronger antibody-dependent cell-mediated cytotoxicity (ADCC) and weaker complement-dependent cytotoxicity (CDC) compared to MabThera. Post-translational modification analysis was performed by peptide mapping using liquid chromatography/mass spectrometry. There was a significant difference in the N-glycosylation profile between the CHO− and the silkworm-derived mAbs, but not in other post-translational modifications including oxidation and deamidation. The mass spectra of the N-glycosylated peptide revealed that the observed biological properties were attributable to the characteristic N-glycan structures of the anti-CD20 mAbs produced in the transgenic silkworms, i.e., the lack of the core-fucose and galactose at the non-reducing terminal. These results suggest that the transgenic silkworm may be a promising expression system for the tumor-targeting mAbs with higher ADCC activity. PMID:26261057

  20. Antigen identification and characterization of lung cancer specific monoclonal antibodies produced by mAb proteomics.

    PubMed

    Wang, Dongdong; Hincapie, Marina; Guergova-Kuras, Mariana; Kadas, Janos; Takacs, Laszlo; Karger, Barry L

    2010-04-01

    A mass spectrometric (MS)-based strategy for antigen (Ag) identification and characterization of globally produced monoclonal antibodies (mAbs) is described. Mice were immunized with a mixture of native glycoproteins, isolated from the pooled plasma of patients with nonsmall cell lung cancer (NSCLC), to generate a library of IgG-secreting hybridomas. Prior to immunization, the pooled NSCLC plasma was subjected to 3-sequential steps of affinity fractionation, including high abundant plasma protein depletion, glycoprotein enrichment, and polyclonal antibody affinity chromatography normalization. In this paper, to demonstrate the high quality of the globally produced mAbs, we selected 3 mAbs of high differentiating power against a matched, pooled normal plasma sample. After production of large quantities of the mAbs from ascites fluids, Ag identification was achieved by immunoaffinity purification, SDS-PAGE, Western blotting, and MS analysis of in-gel digest products. One antigen was found to be complement factor H, and the other two were mapped to different subunits of haptoglobin (Hpt). The 2 Hpt mAbs were characterized in detail to assess the quality of the mAbs produced by the global strategy. The affinity of one of the mAbs to the Hpt native tetramer form was found to have a K(D) of roughly 10(-9) M and to be 2 orders of magnitude lower than the reduced form, demonstrating the power of the mAb proteomics technology in generating mAbs to the natural form of the proteins in blood. The binding of this mAb to the beta-chain of haptoglobin was also dependent on glycosylation on this chain. The characterization of mAbs in this work reveals that the global mAb proteomics process can generate high-quality lung cancer specific mAbs capable of recognizing proteins in their native state. PMID:20146545

  1. Antigen Identification and Characterization of Lung Cancer Specific Monoclonal Antibodies Produced by mAb Proteomics

    PubMed Central

    Wang, Dongdong; Hincapie, Marina; Guergova-Kuras, Mariana; Kadas, Janos; Takacs, Laszlo; Karger, Barry L.

    2010-01-01

    A mass spectrometric (MS)-based strategy for antigen (Ag) identification and characterization of globally produced monoclonal antibodies (mAbs) is described. Mice were immunized with a mixture of native glycoproteins, isolated from the pooled plasma of patients with non-small cell lung cancer (NSCLC), to generate a library of IgG-secreting hybridomas. Prior to immunization, the pooled NSCLC plasma was subjected to 3-sequential steps of affinity fractionation, including high abundant plasma protein depletion, glycoprotein enrichment and polyclonal antibody affinity chromatography normalization. In this paper, in order to demonstrate the high quality of the globally produced mAbs, we selected 3 mAbs of high differentiating power against a matched, pooled normal plasma sample. After production of large quantities of the mAbs from ascites fluids, Ag identification was achieved by immunoaffinity purification, SDS-PAGE, Western blotting and MS analysis of in-gel digest products. One antigen was found to be complement factor H, and the other two were mapped to different subunits of haptoglobin (Hpt). The 2 Hpt mAbs were characterized in detail in order to assess the quality of the mAbs produced by the global strategy. The affinity of one of the mAbs to the Hpt native tetramer form was found to have a KD of roughly 10−9 M and to be 2 orders of magnitude lower than the reduced form, demonstrating the power of the mAb proteomics technology in generating mAbs to the natural form of the proteins in blood. The binding of this mAb to the β-chain of haptoglobin was also dependent on glycosylation on this chain. The characterization of mAbs in this work reveals that the global mAb proteomics process can generate high-quality lung cancer specific mAbs capable of recognizing proteins in their native state. PMID:20146545

  2. Idiotypes of monoclonal anti-DNA antibodies produced in autoimmune B/W mice are expressed in normal mice.

    PubMed Central

    Jacob, L; Tron, F; Lety, M A; Bach, J F

    1986-01-01

    An anti-idiotypic antiserum was prepared in a rabbit immunized against a pool of six monoclonal anti-DNA antibodies generated in B/W mice. This antiserum detected idiotypic determinants in four of the six monoclonal anti-DNA antibodies but also in the serum of several non autoimmune strains (BALB/c, NZB X BALB/c) F1 hybrids & CBA/LH). The antiserum also reacted, but only to a weak degree, with B/W mouse sera. These results indicate that some idiotypes of anti-DNA antibodies produced by autoimmune B/W mice are present in normal mouse sera. PMID:3486065

  3. Characterization of Alpha-Toxin hla Gene Variants, Alpha-Toxin Expression Levels, and Levels of Antibody to Alpha-Toxin in Hemodialysis and Postsurgical Patients with Staphylococcus aureus Bacteremia

    PubMed Central

    Wu, Yuling; Tabor, David E.; Mok, Hoyin; Sellman, Bret R.; Jenkins, Amy; Yu, Li; Jafri, Hasan S.; Rude, Thomas H.; Ruffin, Felicia; Schell, Wiley A.; Park, Lawrence P.; Yan, Qin; Thaden, Joshua T.; Messina, Julia A.; Esser, Mark T.

    2014-01-01

    Alpha-toxin is a major Staphylococcus aureus virulence factor. This study evaluated potential relationships between in vitro alpha-toxin expression of S. aureus bloodstream isolates, anti-alpha-toxin antibody in serum of patients with S. aureus bacteremia (SAB), and clinical outcomes in 100 hemodialysis and 100 postsurgical SAB patients. Isolates underwent spa typing and hla sequencing. Serum anti-alpha-toxin IgG and neutralizing antibody levels were measured by using an enzyme-linked immunosorbent assay and a red blood cell (RBC)-based hemolysis neutralization assay. Neutralization of alpha-toxin by an anti-alpha-toxin monoclonal antibody (MAb MEDI4893) was tested in an RBC-based lysis assay. Most isolates encoded hla (197/200; 98.5%) and expressed alpha-toxin (173/200; 86.5%). In vitro alpha-toxin levels were inversely associated with survival (cure, 2.19 μg/ml, versus failure, 1.09 μg/ml; P < 0.01). Both neutralizing (hemodialysis, 1.26 IU/ml, versus postsurgical, 0.95; P < 0.05) and IgG (hemodialysis, 1.94 IU/ml, versus postsurgical, 1.27; P < 0.05) antibody levels were higher in the hemodialysis population. Antibody levels were also significantly higher in patients infected with alpha-toxin-expressing S. aureus isolates (P < 0.05). Levels of both neutralizing antibodies and IgG were similar among patients who were cured and those not cured (failures). Sequence analysis of hla revealed 12 distinct hla genotypes, and all genotypic variants were susceptible to a neutralizing monoclonal antibody in clinical development (MEDI4893). These data demonstrate that alpha-toxin is highly conserved in clinical S. aureus isolates. Higher in vitro alpha-toxin levels were associated with a positive clinical outcome. Although patients infected with alpha-toxin-producing S. aureus exhibited higher anti-alpha-toxin antibody levels, these levels were not associated with a better clinical outcome in this study. PMID:25392350

  4. Characterization of cysteine related variants in an IgG2 antibody by LC-MS with an automated data analysis approach.

    PubMed

    Zhang, Yuling; Bailey, Robert; Nightlinger, Nancy; Gillespie, Alison; Balland, Alain; Rogers, Richard

    2015-08-01

    In this communication, a high-throughput method for automated data analysis of cysteine-related product quality attributes (PQAs) in IgG2 antibodies is reported. This method leverages recent advances in the relative quantification of PQAs to facilitate the characterization of disulfide variants and free sulfhydryls (SHs) in IgG2 antibodies. The method uses samples labeled with a mass tag (N-ethyl maleimide [NEM]) followed by enzymatic digestion under non-reducing conditions to maintain the cysteine connectivity. The digested IgG2 samples are separated and detected by mass spectrometry (MS) and the resulting peptide map is analyzed in an automated fashion using Pinpoint software (Thermo Scientific). Previous knowledge of IgG2 disulfide structures can be fed into the Pinpoint software to create workbooks for various disulfide linkages and hinge disulfide variants. In addition, the NEM mass tag can be added to the workbooks for targeted analysis of labeled cysteine-containing peptides. The established Pinpoint workbooks are a high-throughput approach to quantify relative abundances of unpaired cysteines and disulfide linkages, including complicated hinge disulfide variants. This approach is especially efficient for comparing large sets of similar samples such as those created in comparability and stability studies or chromatographic fractions. Here, the high throughput method is applied to quantify the relative abundance of hinge disulfide variants and unpaired cysteines in the IgG2 fractions from non-reduced reversed-phase high-performance liquid chromatography (nrRP-HPLC). The LC-MS data analyzed by the Pinpoint workbook suggests that the nrRP-HPLC separated peaks contain hinge disulfide isoforms and free cysteine pairs for each major disulfide isoform structure. PMID:26079266

  5. Guillain-Barré syndrome variant with facial diplegia and paresthesias associated with IgM anti-GalNAc-GD1a antibodies.

    PubMed

    Hayashi, Ryuichiro; Yamaguchi, Shigeki

    2015-01-01

    We herein report the case of a 19-year-old woman with facial diplegia and paresthesias (FDP) preceded by flu-like symptoms. We diagnosed the patient with a regional variant of Guillain-Barré syndrome due to decreased tendon reflexes, albuminocytological dissociation in the cerebrospinal fluid and demyelinating features on nerve conduction studies. The patient also had IgM anti-GalNAc-GD1a antibodies, and treatment with glucocorticoids was effective for treating the facial diplegia, but not paresthesia. Therefore, facial palsy may have a different pathophysiology from paresthesia or other symptoms of FDP, which responds to glucocorticoid therapy. PMID:25748745

  6. Molecular modeling assisted hapten design to produce broad selectivity antibodies for fluoroquinolone antibiotics.

    PubMed

    Pinacho, Daniel G; Sánchez-Baeza, Francisco; Marco, M-Pilar

    2012-05-15

    Antibodies with a wide recognition profile of fluoroquinolone antibiotics have been produced based on chemical criteria, theoretical studies, and molecular modeling assisted hapten design. The immunizing hapten preserves the most important and characteristic epitopes of this antibiotic family. The studies have taken into consideration the zwitterionic character of most of the fluoroquinolones and the relative concentration of the different species in equilibrium at physiologic pH. The hapten is prepared in the form of a stable prehapten through a 5 step synthetic pathway. Immediately before conjugation, the immunizing hapten is obtained by removing the diphenylmethane protecting group. The specificity of the antibodies obtained is directed toward the common area defined by the fluorine atom at position 6 and the β-ketoacid moiety. The ELISA developed is able to recognize with very good detectability important fluoroquinolones used in the veterinary field such as ciprofloxacin (CPFX, IC(50), 0.35 μg L(-1)), enrofloxacin (ERFX, IC(50), 0.65 μg L(-1)), danofloxacin (DNFX, IC(50), 7.31 μg L(-1)), difloxacin (DFX, IC(50), 0.91 μg L(-1)), sarafloxacin (SRFX, IC(50), 0.96 μg L(-1)), norfloxacin (NRFX, IC(50), 0.78 μg L(-1)), ofloxacin (OFX, IC(50), 1.84 μg L(-1)), flumequine (Flume, IC(50), 3.91 μ gL(-1)), marbofloxacin (MBFX, IC(50), 4.30 μ gL(-1)), and oxolinic acid (OXO, IC(50), 23.53 μg L(-1)). The results presented here demonstrate that the antibody affinity is strongly affected by the presence of divalent cations, owing to their complexation with the fluoroquinolone molecules. Moreover, the outcome from the effect of the pH on the immunochemical assays suggests that the selectivity could be modulated with the pH due to the zwitterionic character of the fluoroquinolones and as a function of their different pK(a) values. PMID:22545705

  7. Understanding Transcriptional Enhancement in Monoclonal Antibody-Producing Chinese Hamster Ovary Cells

    NASA Astrophysics Data System (ADS)

    Nicoletti, Sarah E.

    With the demand for monoclonal antibody (mAB) therapeutics continually increasing, the need to better understand what makes a high productivity clone has gained substantial interest. Monoclonal antibody producing Chinese hamster ovary (CHO) cells with different productivities were provided by a biopharmaceutical company for investigation. Gene copy numbers, mRNA levels, and mAb productivities were previously determined for two low producing clones and their amplified progeny. These results showed an increase in mRNA copy number in amplified clones, which correlated to the observed increases in specific productivity of these clones. The presence of multiple copies of mRNA per one copy of DNA in the higher productivity clones has been coined as transcriptional enhancement. The methylation status of the CMV promoter as well as transcription factor/promoter interactions were evaluated to determine the cause of transcriptional enhancement. Methylation analysis via bisulfite sequencing revealed no significant difference in overall methylation status of the CMV promoter. These data did, however, reveal the possibility of differential interactions of transcription factors between the high and low productivity cell clones. This finding was further supported by chromatin immunoprecipitations previously performed in the lab, as well as literature studies. Transcription activator-like effector (TALE) binding proteins were constructed and utilized to selectively immunoprecipitate the CMV promoter along with its associated transcription factors in the different CHO cell clones. Cells were transfected with the TALE proteins, harvested and subjected to a ChIP-like procedure. Results obtained from the TALE ChIP demonstrated the lack of binding of the protein to the promoter and the need to redesign the TALE. Overall, results obtained from this study were unable to give a clear indication as to the causes of transcriptional enhancement in the amplified CHO cell clones. Further

  8. Human/BALB radiation chimera engrafted with splenocytes from patients with idiopathic thrombocytopenic purpura produce human platelet antibodies.

    PubMed Central

    Dekel, B; Marcus, H; Shenkman, B; Shimoni, A; Shechter, Y; Canaan, A; Berrebi, A; Varon, D; Reisner, Y

    1998-01-01

    We have previously shown that lethally irradiated normal strains of mice, radioprotected with severe combined immunodeficient (SCID) bone marrow, can be engrafted with human peripheral blood mononuclear cells (PBMC). The human/mouse radiation chimera can mount marked humoral and cellular responses to recall antigens, as well as primary responses. In the present study, we adoptively transferred splenocytes from patients with chronic immune thrombocytopenic purpura (ITP) into lethally irradiated BALB/c mice, radioprotected with SCID bone marrow. High titres of total human immunoglobulin appeared as early as 2 weeks post-transplant and declined after 6 weeks, while human anti-human platelet antibodies were detected 2-8 weeks after the transfer of splenocytes. The immunoglobulin G (IgG) fraction contained antibodies against glycoprotein (GP) IIb/IIIa (CD41) or GPIb/IX (CD42). The human platelet antibodies showed a low level of cross-reactivity with mouse platelets, and thrombocytopenia in the animals was not observed. Splenocytes from individual ITP patients differed in their capacity to produce either human platelet antibodies or total human immunoglobulin. Furthermore, antibodies produced in the murine system were not always identical to the original antibodies present in the serum of the patients. The study of the serological aspects of autoantibodies against human platelets in an animal model might be useful for the investigation of potential therapeutics in ITP. PMID:9767425

  9. Aβ anti-idiotypic antibodies are present in intravenous immunoglobulin and are produced in mice following its administration.

    PubMed

    Loeffler, David A; Klaver, Andrea C; Coffey, Mary P

    2015-06-01

    The effects of intravenous immunoglobulin (IVIG) products were recently examined in patients with Alzheimer's disease (AD). Although encouraging results were obtained in pilot studies, later trials produced negative results. The rationale for these studies was that IVIG contains antibodies to amyloid-beta (Aβ). However, if Aβ anti-idiotypic antibodies (antibodies which bind to anti-Aβ antibodies) are present in IVIG or induced by its administration, these antibodies could potentially reduce its neuroprotective effects in AD. The objective of this study was to determine if IVIG contained such antibodies. Enzyme-linked immunosorbent assays (ELISAs) measured specific binding of IVIG Gamunex to purified human anti-Aβ IgG. The mean concentration of its Aβ anti-idiotypic antibodies in four experiments was 1.85 μg/mL (18.5 μg/g IgG; range = 1.82-1.89 μg/mL [18.2-18.9 μg/g IgG]), and their mean percentage of specific binding was 72.2% (range = 68.3-75.3%). We then performed ELISAs to determine if antibodies to purified human anti-Aβ were produced in C57BL/6 mice injected with the IVIG product Gammagard in an earlier study. After subtracting the expected immune response to normal human immunoglobulins, the median concentrations of these antibodies were 15.6 ng/mL (range = 1.2-108.2 ng/mL) in pre-treatment sera and 2419.4 ng/mL (range = 327.4-8478.4 ng/mL) in post-treatment sera. These results indicate that specific Aβ anti-idiotypic antibodies are detectable in IVIG and may be induced in mice by its administration. The presence of Aβ anti-idiotypic antibodies in IVIG products might decrease neuroprotective effects of their anti-Aβ antibodies in AD. PMID:25392130

  10. Campylobacter hyointestinalis Isolated from Pigs Produces Multiple Variants of Biologically Active Cytolethal Distending Toxin.

    PubMed

    Kamei, Kazumasa; Hatanaka, Noritoshi; Asakura, Masahiro; Somroop, Srinuan; Samosornsuk, Worada; Hinenoya, Atsushi; Misawa, Naoaki; Nakagawa, Shinsaku; Yamasaki, Shinji

    2015-11-01

    Campylobacter hyointestinalis isolated from swine with proliferative enteritis often is considered to be pathogenic. While the precise virulence mechanisms of this species remain unclear, we have recently identified a cytolethal distending toxin (cdt) gene cluster in C. hyointestinalis isolated from a patient with diarrhea (W. Samosornsuk et al., J Med Microbiol, 27 July 2015, http://dx.doi.org/10.1099/jmm.0.000145). However, the sequences of the cdt genes in C. hyointestinalis were found to be significantly different and the gene products are immunologically distinct from those of other Campylobacter species. In this study, we demonstrate the presence of a second variant of the cdt gene cluster in C. hyointestinalis, designated cdt-II, while the former is named cdt-I. Sequencing of the cdt-II gene cluster and deduced amino acid sequences revealed that homologies between the subunits CdtA, CdtB, and CdtC of ChCDT-I and ChCDT-II are 25.0, 56.0, and 24.8%, respectively. Furthermore, the CdtB subunit of ChCDT-II was found to be immunologically unrelated to that of ChCDT-I by Ouchterlony double gel diffusion test. Recombinant ChCDT-II also induced cell distention and death of HeLa cells by blocking the cell cycle at G2/M phase. Interestingly, the cdt-II genes were detected in all 23 animal isolates and in 1 human isolate of C. hyointestinalis, and 21 of these strains carried both cdt-I and cdt-II gene clusters. Altogether, our results indicate that ChCDT-II is an important virulence factor of C. hyointestinalis in animals. PMID:26283337

  11. Campylobacter hyointestinalis Isolated from Pigs Produces Multiple Variants of Biologically Active Cytolethal Distending Toxin

    PubMed Central

    Kamei, Kazumasa; Hatanaka, Noritoshi; Asakura, Masahiro; Somroop, Srinuan; Samosornsuk, Worada; Hinenoya, Atsushi; Misawa, Naoaki; Nakagawa, Shinsaku

    2015-01-01

    Campylobacter hyointestinalis isolated from swine with proliferative enteritis often is considered to be pathogenic. While the precise virulence mechanisms of this species remain unclear, we have recently identified a cytolethal distending toxin (cdt) gene cluster in C. hyointestinalis isolated from a patient with diarrhea (W. Samosornsuk et al., J Med Microbiol, 27 July 2015, http://dx.doi.org/10.1099/jmm.0.000145). However, the sequences of the cdt genes in C. hyointestinalis were found to be significantly different and the gene products are immunologically distinct from those of other Campylobacter species. In this study, we demonstrate the presence of a second variant of the cdt gene cluster in C. hyointestinalis, designated cdt-II, while the former is named cdt-I. Sequencing of the cdt-II gene cluster and deduced amino acid sequences revealed that homologies between the subunits CdtA, CdtB, and CdtC of ChCDT-I and ChCDT-II are 25.0, 56.0, and 24.8%, respectively. Furthermore, the CdtB subunit of ChCDT-II was found to be immunologically unrelated to that of ChCDT-I by Ouchterlony double gel diffusion test. Recombinant ChCDT-II also induced cell distention and death of HeLa cells by blocking the cell cycle at G2/M phase. Interestingly, the cdt-II genes were detected in all 23 animal isolates and in 1 human isolate of C. hyointestinalis, and 21 of these strains carried both cdt-I and cdt-II gene clusters. Altogether, our results indicate that ChCDT-II is an important virulence factor of C. hyointestinalis in animals. PMID:26283337

  12. Biochemical Characterization of Human Anti-Hepatitis B Monoclonal Antibody Produced in the Microalgae Phaeodactylum tricornutum

    PubMed Central

    Vanier, Gaëtan; Hempel, Franziska; Chan, Philippe; Rodamer, Michael; Vaudry, David; Maier, Uwe G.; Lerouge, Patrice; Bardor, Muriel

    2015-01-01

    Monoclonal antibodies (mAbs) represent actually the major class of biopharmaceuticals. They are produced recombinantly using living cells as biofactories. Among the different expression systems currently available, microalgae represent an emerging alternative which displays several biotechnological advantages. Indeed, microalgae are classified as generally recognized as safe organisms and can be grown easily in bioreactors with high growth rates similarly to CHO cells. Moreover, microalgae exhibit a phototrophic lifestyle involving low production costs as protein expression is fueled by photosynthesis. However, questions remain to be solved before any industrial production of algae-made biopharmaceuticals. Among them, protein heterogeneity as well as protein post-translational modifications need to be evaluated. Especially, N-glycosylation acquired by the secreted recombinant proteins is of major concern since most of the biopharmaceuticals including mAbs are N-glycosylated and it is well recognized that glycosylation represent one of their critical quality attribute. In this paper, we assess the quality of the first recombinant algae-made mAbs produced in the diatom, Phaeodactylum tricornutum. We are focusing on the characterization of their C- and N-terminal extremities, their signal peptide cleavage and their post-translational modifications including N-glycosylation macro- and microheterogeneity. This study brings understanding on diatom cellular biology, especially secretion and intracellular trafficking of proteins. Overall, it reinforces the positioning of P. tricornutum as an emerging host for the production of biopharmaceuticals and prove that P. tricornutum is suitable for producing recombinant proteins bearing high mannose-type N-glycans. PMID:26437211

  13. Biochemical Characterization of Human Anti-Hepatitis B Monoclonal Antibody Produced in the Microalgae Phaeodactylum tricornutum.

    PubMed

    Vanier, Gaëtan; Hempel, Franziska; Chan, Philippe; Rodamer, Michael; Vaudry, David; Maier, Uwe G; Lerouge, Patrice; Bardor, Muriel

    2015-01-01

    Monoclonal antibodies (mAbs) represent actually the major class of biopharmaceuticals. They are produced recombinantly using living cells as biofactories. Among the different expression systems currently available, microalgae represent an emerging alternative which displays several biotechnological advantages. Indeed, microalgae are classified as generally recognized as safe organisms and can be grown easily in bioreactors with high growth rates similarly to CHO cells. Moreover, microalgae exhibit a phototrophic lifestyle involving low production costs as protein expression is fueled by photosynthesis. However, questions remain to be solved before any industrial production of algae-made biopharmaceuticals. Among them, protein heterogeneity as well as protein post-translational modifications need to be evaluated. Especially, N-glycosylation acquired by the secreted recombinant proteins is of major concern since most of the biopharmaceuticals including mAbs are N-glycosylated and it is well recognized that glycosylation represent one of their critical quality attribute. In this paper, we assess the quality of the first recombinant algae-made mAbs produced in the diatom, Phaeodactylum tricornutum. We are focusing on the characterization of their C- and N-terminal extremities, their signal peptide cleavage and their post-translational modifications including N-glycosylation macro- and microheterogeneity. This study brings understanding on diatom cellular biology, especially secretion and intracellular trafficking of proteins. Overall, it reinforces the positioning of P. tricornutum as an emerging host for the production of biopharmaceuticals and prove that P. tricornutum is suitable for producing recombinant proteins bearing high mannose-type N-glycans. PMID:26437211

  14. Directed selection of influenza virus produces antigenic variants that match circulating human virus isolates and escape from vaccine-mediated immune protection.

    PubMed

    DeDiego, Marta L; Anderson, Christopher S; Yang, Hongmei; Holden-Wiltse, Jeanne; Fitzgerald, Theresa; Treanor, John J; Topham, David J

    2016-06-01

    Influenza vaccination does not provide 100% protection from infection, partly due to antigenic drift of the haemagglutinin (HA) protein. Low serum antibody titres increase the risk of infection. To determine whether there were additional correlates of risk, we examined the relationship between human serum immunity and antigenic variation in seasonal H3N2 influenza viruses. Seasonal H3N2 vaccine strains grown in the presence of heterogeneous human or mono-specific ferret antisera selected variants with mutations in the HA antigenic sites. Surprisingly, circulating strains infecting human subjects in the same seasons displayed mutations in the same positions, although only in one case did the change correspond to the same amino acid. Serum antibody titres were lower against both the in vitro selected and clinical isolates compared with the vaccine strains, suggesting that the mutations are relevant to vaccine failure. Antibody titres were also significantly lower in sera from infected subjects than in non-infected subjects, suggesting relatively poor responses to vaccination in the infected subjects. Collectively, the data suggest that risk from influenza infection is a result of poor response to vaccination, as well as encounter with drifted seasonal influenza virus antigenic variants. The results also show that directed selection under human immune pressure could reveal antigenic variants relevant to real-world drifted viruses, helping in annual vaccine re-formulation. PMID:26854888

  15. Nisin H Is a New Nisin Variant Produced by the Gut-Derived Strain Streptococcus hyointestinalis DPC6484.

    PubMed

    O'Connor, Paula M; O'Shea, Eileen F; Guinane, Caitriona M; O'Sullivan, Orla; Cotter, Paul D; Ross, R Paul; Hill, Colin

    2015-06-15

    Accumulating evidence suggests that bacteriocin production represents a probiotic trait for intestinal strains to promote dominance, fight infection, and even signal the immune system. In this respect, in a previous study, we isolated from the porcine intestine a strain of Streptococcus hyointestinalis DPC6484 that displays antimicrobial activity against a wide range of Gram-positive bacteria and produces a bacteriocin with a mass of 3,453 Da. Interestingly, the strain was also found to be immune to a nisin-producing strain. Genome sequencing revealed the genetic determinants responsible for a novel version of nisin, designated nisin H, consisting of the nshABTCPRKGEF genes, with transposases encoded between nshP and nshR and between nshK and nshG. A similar gene cluster is also found in S. hyointestinalis LMG14581. Notably, the cluster lacks an equivalent of the nisin immunity gene, nisI. Nisin H is proposed to have the same structure as the prototypical nisin A but differs at 5 amino acid positions-Ile1Phe (i.e., at position 1, nisin A has Ile while nisin H has Phe), Leu6Met, Gly18Dhb (threonine dehydrated to dehydrobutyrine), Met21Tyr, and His31Lys--and appears to represent an intermediate between the lactococcal nisin A and the streptococcal nisin U variant of nisin. Purified nisin H inhibits a wide range of Gram-positive bacteria, including staphylococci, streptococci, Listeria spp., bacilli, and enterococci. It represents the first example of a natural nisin variant produced by an intestinal isolate of streptococcal origin. PMID:25841003

  16. Nisin H Is a New Nisin Variant Produced by the Gut-Derived Strain Streptococcus hyointestinalis DPC6484

    PubMed Central

    O'Connor, Paula M.; O'Shea, Eileen F.; Guinane, Caitriona M.; O'Sullivan, Orla; Cotter, Paul D.; Hill, Colin

    2015-01-01

    Accumulating evidence suggests that bacteriocin production represents a probiotic trait for intestinal strains to promote dominance, fight infection, and even signal the immune system. In this respect, in a previous study, we isolated from the porcine intestine a strain of Streptococcus hyointestinalis DPC6484 that displays antimicrobial activity against a wide range of Gram-positive bacteria and produces a bacteriocin with a mass of 3,453 Da. Interestingly, the strain was also found to be immune to a nisin-producing strain. Genome sequencing revealed the genetic determinants responsible for a novel version of nisin, designated nisin H, consisting of the nshABTCPRKGEF genes, with transposases encoded between nshP and nshR and between nshK and nshG. A similar gene cluster is also found in S. hyointestinalis LMG14581. Notably, the cluster lacks an equivalent of the nisin immunity gene, nisI. Nisin H is proposed to have the same structure as the prototypical nisin A but differs at 5 amino acid positions—Ile1Phe (i.e., at position 1, nisin A has Ile while nisin H has Phe), Leu6Met, Gly18Dhb (threonine dehydrated to dehydrobutyrine), Met21Tyr, and His31Lys—-and appears to represent an intermediate between the lactococcal nisin A and the streptococcal nisin U variant of nisin. Purified nisin H inhibits a wide range of Gram-positive bacteria, including staphylococci, streptococci, Listeria spp., bacilli, and enterococci. It represents the first example of a natural nisin variant produced by an intestinal isolate of streptococcal origin. PMID:25841003

  17. Characterisation of the LH2 spectral variants produced by the photosynthetic purple sulphur bacterium Allochromatium vinosum.

    PubMed

    Carey, Anne-Marie; Hacking, Kirsty; Picken, Nichola; Honkanen, Suvi; Kelly, Sharon; Niedzwiedzki, Dariusz M; Blankenship, Robert E; Shimizu, Yuuki; Wang-Otomo, Zheng-Yu; Cogdell, Richard J

    2014-11-01

    This study systematically investigated the different types of LH2 produced by Allochromatium (Alc.) vinosum, a photosynthetic purple sulphur bacterium, in response to variations in growth conditions. Three different spectral forms of LH2 were isolated and purified, the B800-820, B800-840 and B800-850 LH2 types, all of which exhibit an unusual split 800 peak in their low temperature absorption spectra. However, it is likely that more forms are also present. Relatively more B800-820 and B800-840 are produced under low light conditions, while relatively more B800-850 is produced under high light conditions. Polypeptide compositions of the three different LH2 types were determined by a combination of HPLC and TOF/MS. The B800-820, B800-840 and B800-850 LH2 types all have a heterogeneous polypeptide composition, containing multiple types of both α and β polypeptides, and differ in their precise polypeptide composition. They all have a mixed carotenoid composition, containing carotenoids of the spirilloxanthin series. In all cases the most abundant carotenoid is rhodopin; however, there is a shift towards carotenoids with a higher conjugation number in LH2 complexes produced under low light conditions. CD spectroscopy, together with the polypeptide analysis, demonstrates that these Alc. vinosum LH2 complexes are more closely related to the LH2 complex from Phs. molischianum than they are to the LH2 complexes from Rps. acidophila. PMID:25111749

  18. Identification and characterization of a -1 reading frameshift in the heavy chain constant region of an IgG1 recombinant monoclonal antibody produced in CHO cells.

    PubMed

    Lian, Zhirui; Wu, Qindong; Wang, Tongtong

    2016-01-01

    Frameshifts lead to complete alteration of the intended amino acid sequences, and therefore may affect the biological activities of protein therapeutics and pose potential immunogenicity risks. We report here the identification and characterization of a novel -1 frameshift variant in a recombinant IgG1 therapeutic monoclonal antibody (mAb) produced in Chinese hamster ovary cells during the cell line selection studies. The variant was initially observed as an atypical post-monomer fragment peak in size exclusion chromatography. Characterization of the fragment peak using intact and reduced liquid chromatography-mass spectrometry (LC-MS) analyses determined that the fragment consisted of a normal light chain disulfide-linked to an aberrant 26 kDa fragment that could not be assigned to any HC fragment even after considering common modifications. Further analysis using LC-MS/MS peptide mapping revealed that the aberrant fragment contained the expected HC amino acid sequence (1-232) followed by a 20-mer novel sequence corresponding to expression of heavy chain DNA sequence in the -1 reading frame. Examination of the DNA sequence around the frameshift initiation site revealed that a mononucleotide repeat GGGGGG located in the IgG1 HC constant region was most likely the structural root cause of the frameshift. Rapid identification of the frameshift allowed us to avoid use of a problematic cell line containing the frameshift as the production cell line. The frameshift reported here may be observed in other mAb products and the hypothesis-driven analytical approaches employed here may be valuable for rapid identification and characterization of frameshift variants in other recombinant proteins. PMID:26652198

  19. Monoclonal antibodies against all known variants of EspA: development of a simple diagnostic test for enteropathogenic Escherichia coli based on a key virulence factor

    PubMed Central

    Reissbrodt, Rolf; Kresse, Andreas; Pavankumar, Asalapuram; Sankaran, Krishnan; James, Roger; Jesudason, Mary; Anandan, Shalini; Prakasam, Agila; Balaji, Veeraraghavan; Dutta, Shanta; Dutta, Sanjucta; Ramamurthy, Thandavarayan; Fischer, Renate; Sander, Peter; Schaumann, Reiner; Navarro, Armando; Williams, Peter

    2014-01-01

    Enteropathogenic Escherichia coli (EPEC) are a major cause of infant diarrhoea in developing countries and a significant public health issue in industrialized countries. Currently there are no simple tests available for the diagnosis of EPEC. Serology of O-antigens is widely used routinely in many laboratories throughout the world, even though it has been known for many years to be an unreliable indicator of EPEC virulence. We have developed a simple, low-cost immunodiagnostic test based on the EspA filament, an essential virulence factor of EPEC and the related enterohaemorrhagic E. coli (EHEC). Using recombinant proteins of the five major variants of EspA as immunogens, we raised a panel of three monoclonal antibodies in mice that detects all variants of the native target in bacterial cultures. The antibodies proved suitable for application in sandwich-type assays, including ELISA and lateral flow immunoassays (LFI). Prototypes for both assays were specific for EPEC and EHEC strains when tested against a panel of control micro-organisms. We have also developed a simple, affordable culture medium, A/E medium, which optimizes expression of EspA allowing improved sensitivity of detection compared with standard Dulbecco’s modified Eagle’s medium. Together these reagents form the basis of robust, informative tests for EPEC for use especially in developing countries but also for routine screening in any clinical laboratory. PMID:25231626

  20. Rapid O serogroup identification of the six clinically relevant Shiga toxin-producing Escherichia coli by antibody microarray

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibody array was developed for the detection of the top six non-O157 Shiga toxin-producing Escherichia coli O serogroups. Sensitivity of the array was 10**5 CFU, and the limit of detection of serogroups in ground beef was 1-10 CFU following 12 h of enrichment. The array utilized a minimal amount...

  1. RrgB321, a Fusion Protein of the Three Variants of the Pneumococcal Pilus Backbone RrgB, Is Protective In Vivo and Elicits Opsonic Antibodies

    PubMed Central

    Harfouche, Carole; Filippini, Sara; Gianfaldoni, Claudia; Ruggiero, Paolo; Moschioni, Monica; Maccari, Silvia; Pancotto, Laura; Arcidiacono, Letizia; Galletti, Bruno; Censini, Stefano; Mori, Elena; Giuliani, Marzia; Facciotti, Claudia; Cartocci, Elena; Savino, Silvana; Doro, Francesco; Pallaoro, Michele; Nocadello, Salvatore; Mancuso, Giuseppe; Haston, Mitch; Goldblatt, David; Barocchi, Michèle A.; Pizza, Mariagrazia; Rappuoli, Rino

    2012-01-01

    Streptococcus pneumoniae pilus 1 is present in 30 to 50% of invasive disease-causing strains and is composed of three subunits: the adhesin RrgA, the major backbone subunit RrgB, and the minor ancillary protein RrgC. RrgB exists in three distinct genetic variants and, when used to immunize mice, induces an immune response specific for each variant. To generate an antigen able to protect against the infection caused by all pilus-positive S. pneumoniae strains, we engineered a fusion protein containing the three RrgB variants (RrgB321). RrgB321 elicited antibodies against proteins from organisms in the three clades and protected mice against challenge with piliated pneumococcal strains. RrgB321 antisera mediated complement-dependent opsonophagocytosis of piliated strains at levels comparable to those achieved with the PCV7 glycoconjugate vaccine. These results suggest that a vaccine composed of RrgB321 has the potential to cover 30% or more of all pneumococcal strains and support the inclusion of this fusion protein in a multicomponent vaccine against S. pneumoniae. PMID:22083702

  2. Antibodies to variant surface antigens of Plasmodium falciparum infected erythrocytes associated with protection from treatment failure and development of anaemia in pregnancy

    PubMed Central

    Feng, Gaoqian; Aitken, Elizabeth; Yosaatmadja, Francisca; Kalilani, Linda; Meshnick, Steven R; Jaworowski, Anthony; Simpson, Julie A; Rogerson, Stephen J

    2009-01-01

    Background In pregnancy associated malaria (PAM), Plasmodium falciparum infected erythrocytes (IEs) express variant surface antigens (VSA-PAM) that evade existing immunity and mediate placental sequestration. Antibodies to VSA-PAM develop with gravidity and block placental adhesion or opsonise IEs for phagocytic clearance, protecting women from anemia and low birth weight Methods and findings Using sera from 141 parasitemic pregnant Malawian women enrolled in a randomized trial of antimalarials and VSA-PAM-expressing CS2 IEs, we quantitated levels of IgG to VSA-PAM by flow cytometry and opsonizing antibodies by measuring uptake of IEs by THP1 promonocytes. After controlling for gravidity and antimalarial treatment, IgG against VSA-PAM was associated with decreased anemia at delivery (OR=0.66, 95% confidence interval [CI] 0.46, 0.93; P=0.018) and weakly associated with decreased parasitological failure (OR=0.78; 95% CI, 0.60, 1.03; P=0.075), especially re-infection (OR=0.73; CI, 0.53,1.01; P=0.057). Opsonizing antibodies to CS2 IE were associated with less maternal anemia. (OR=0.31, 95% CI, 0.13, 0.74; P=0.008) and treatment failure (OR=0.48; 95% CI, 0.25, 0.90; P=0.023), primarily due to recrudescent infection (OR=0.49; 95% CI, 0.21, 1.12; P=0.089). Conclusion Both IgG antibody to VSA-PAM and opsonizing antibody, a functional measure of immunity correlate with parasite clearance and less anemia in pregnancy malaria. PMID:19500037

  3. Conformational and functional variants of CD44-targeted protein nanoparticles bio-produced in bacteria.

    PubMed

    Pesarrodona, Mireia; Fernández, Yolanda; Foradada, Laia; Sánchez-Chardi, Alejandro; Conchillo-Solé, Oscar; Unzueta, Ugutz; Xu, Zhikun; Roldán, Mónica; Villegas, Sandra; Ferrer-Miralles, Neus; Schwartz, Simó; Rinas, Ursula; Daura, Xavier; Abasolo, Ibane; Vázquez, Esther; Villaverde, Antonio

    2016-06-01

    Biofabrication is attracting interest as a means to produce nanostructured functional materials because of its operational versatility and full scalability. Materials based on proteins are especially appealing, as the structure and functionality of proteins can be adapted by genetic engineering. Furthermore, strategies and tools for protein production have been developed and refined steadily for more than 30 years. However, protein conformation and therefore activity might be sensitive to production conditions. Here, we have explored whether the downstream strategy influences the structure and biological activities, in vitro and in vivo, of a self-assembling, CD44-targeted protein-only nanoparticle produced in Escherichia coli. This has been performed through the comparative analysis of particles built from soluble protein species or protein versions obtained by in vitro protein extraction from inclusion bodies, through mild, non-denaturing procedures. These methods have been developed recently as a convenient alternative to the use of toxic chaotropic agents for protein resolubilization from protein aggregates. The results indicate that the resulting material shows substantial differences in its physicochemical properties and its biological performance at the systems level, and that its building blocks are sensitive to the particular protein source. PMID:27078873

  4. Ebola virus-like particles produced in insect cells exhibit dendritic cell stimulating activity and induce neutralizing antibodies

    SciTech Connect

    Ye Ling; Lin Jianguo; Sun Yuliang; Bennouna, Soumaya; Lo, Michael; Wu Qingyang; Bu Zhigao; Pulendran, Bali; Compans, Richard W. . E-mail: compans@microbio.emory.edu; Yang Chinglai . E-mail: chyang@emory.edu

    2006-08-01

    Recombinant baculoviruses (rBV) expressing Ebola virus VP40 (rBV-VP40) or GP (rBV-GP) proteins were generated. Infection of Sf9 insect cells by rBV-VP40 led to assembly and budding of filamentous particles from the cell surface as shown by electron microscopy. Ebola virus-like particles (VLPs) were produced by coinfection of Sf9 cells with rBV-VP40 and rBV-GP, and incorporation of Ebola GP into VLPs was demonstrated by SDS-PAGE and Western blot analysis. Recombinant baculovirus infection of insect cells yielded high levels of VLPs, which were shown to stimulate cytokine secretion from human dendritic cells similar to VLPs produced in mammalian cells. The immunogenicity of Ebola VLPs produced in insect cells was evaluated by immunization of mice. Analysis of antibody responses showed that most of the GP-specific antibodies were of the IgG2a subtype, while no significant level of IgG1 subtype antibodies specific for GP was induced, indicating the induction of a Th1-biased immune response. Furthermore, sera from Ebola VLP immunized mice were able to block infection by Ebola GP pseudotyped HIV virus in a single round infection assay, indicating that a neutralizing antibody against the Ebola GP protein was induced. These results show that production of Ebola VLPs in insect cells using recombinant baculoviruses represents a promising approach for vaccine development against Ebola virus infection.

  5. The CEA/CD3-Bispecific Antibody MEDI-565 (MT111) Binds a Nonlinear Epitope in the Full-Length but Not a Short Splice Variant of CEA

    PubMed Central

    Huang, Jiaqi; Brohawn, Philip; Morehouse, Chris; Lekstrom, Kristen; Baeuerle, Patrick A.; Wu, Herren; Yao, Yihong; Coats, Steven R.; Dall’Acqua, William; Damschroder, Melissa; Hammond, Scott A.

    2012-01-01

    MEDI-565 (also known as MT111) is a bispecific T-cell engager (BiTE®) antibody in development for the treatment of patients with cancers expressing carcinoembryonic antigen (CEA). MEDI-565 binds CEA on cancer cells and CD3 on T cells to induce T-cell mediated killing of cancer cells. To understand the molecular basis of human CEA recognition by MEDI-565 and how polymorphisms and spliced forms of CEA may affect MEDI-565 activity, we mapped the epitope of MEDI-565 on CEA using mutagenesis and homology modeling approaches. We found that MEDI-565 recognized a conformational epitope in the A2 domain comprised of amino acids 326–349 and 388–410, with critical residues F326, T328, N333, V388, G389, P390, E392, I408, and N410. Two non-synonymous single-nucleotide polymorphisms (SNPs) (rs10407503, rs7249230) were identified in the epitope region, but they are found at low homozygosity rates. Searching the National Center for Biotechnology Information GenBank® database, we further identified a single, previously uncharacterized mRNA splice variant of CEA that lacks a portion of the N-terminal domain, the A1 and B1 domains, and a large portion of the A2 domain. Real-time quantitative polymerase chain reaction analysis of multiple cancers showed widespread expression of full-length CEA in these tumors, with less frequent but concordant expression of the CEA splice variant. Because the epitope was largely absent from the CEA splice variant, MEDI-565 did not bind or mediate T-cell killing of cells solely expressing this form of CEA. In addition, the splice variant did not interfere with MEDI-565 binding or activity when co-expressed with full-length CEA. Thus MEDI-565 may broadly target CEA-positive tumors without regard for expression of the short splice variant of CEA. Together our data suggest that MEDI-565 activity will neither be impacted by SNPs nor by a splice variant of CEA. PMID:22574157

  6. Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves.

    PubMed

    Valgaeren, Bonnie R; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

    2015-07-01

    Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin. PMID:26184311

  7. Veal Calves Produce Less Antibodies against C. Perfringens Alpha Toxin Compared to Beef Calves

    PubMed Central

    Valgaeren, Bonnie R.; Pardon, Bart; Goossens, Evy; Verherstraeten, Stefanie; Roelandt, Sophie; Timbermont, Leen; Van Der Vekens, Nicky; Stuyvaert, Sabrina; Gille, Linde; Van Driessche, Laura; Haesebrouck, Freddy; Ducatelle, Richard; Van Immerseel, Filip; Deprez, Piet

    2015-01-01

    Enterotoxaemia is a disease with a high associated mortality rate, affecting beef and veal calves worldwide, caused by C. perfringens alpha toxin and perfringolysin. A longitudinal study was conducted to determine the dynamics of antibodies against these toxins in 528 calves on 4 beef and 15 veal farms. The second study aimed to determine the effect of solid feed intake on the production of antibodies against alpha toxin and perfringolysin. The control group only received milk replacer, whereas in the test group solid feed was provided. Maternal antibodies for alpha toxin were present in 45% of the veal calves and 66% of the beef calves. In beef calves a fluent transition from maternal to active immunity was observed for alpha toxin, whereas almost no veal calves developed active immunity. Perfringolysin antibodies significantly declined both in veal and beef calves. In the second study all calves were seropositive for alpha toxin throughout the experiment and solid feed intake did not alter the dynamics of alpha and perfringolysin antibodies. In conclusion, the present study showed that veal calves on a traditional milk replacer diet had significantly lower alpha toxin antibodies compared to beef calves in the risk period for enterotoxaemia, whereas no differences were noticed for perfringolysin. PMID:26184311

  8. Mountain Yellow-legged Frogs (Rana muscosa) did not Produce Detectable Antibodies in Immunization Experiments with Batrachochytrium dendrobatidis.

    PubMed

    Poorten, Thomas J; Stice-Kishiyama, Mary J; Briggs, Cheryl J; Rosenblum, Erica Bree

    2016-01-01

    Chytridiomycosis is a devastating infectious disease of amphibians caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). A growing number of studies have examined the role of amphibian adaptive immunity in response to this pathogen, with varying degrees of immune activation reported. Here we present immunologic data for the mountain yellow-legged frog, Rana muscosa, and the Sierra Nevada yellow-legged frog, Rana sierrae, which are two endangered and ecologically important species experiencing Bd-inflicted declines. Previous studies on these species that examined transcriptional response during Bd infection, and the effective of immunization, provided little evidence of immune activation to Bd. However, the studies did not directly assay immune effectors in the frog hosts. We performed experiments to examine antibody production, which is a hallmark of systemic adaptive immune activation. We used controlled laboratory experiments and enzyme-linked immunosorbent assays to examine the antibody response to Bd immunization and live Bd exposure. Rana muscosa and R. sierrae individuals did not produce detectable antibodies with the capacity to bind to denatured Bd antigens under our experimental conditions. While we cannot rule out antibody response to Bd in these species, our results suggest weak, poor, or inefficient production of antibodies to denatured Bd antigens. Our findings are consistent with susceptibility to chytridiomycosis in these species and suggest additional work is needed to characterize the potential for adaptive immunity. PMID:26540180

  9. Real-time PCR for differentiation of F18 variants among enterotoxigenic and Shiga toxin-producing Escherichia coli from piglets with diarrhoea and oedema disease.

    PubMed

    Byun, Jae-Won; Jung, Byeong Yeal; Kim, Ha-Young; Fairbrother, John M; Lee, Myoung-Heon; Lee, Wan-Kyu

    2013-11-01

    One-step real-time PCR using one set of primers and four probes was developed for differentiation of F18 variants (F18 common, F18ab, F18ac, F18new variant) of enterotoxigenic (ETEC) and Shiga toxin-producing (STEC) Escherichia coli from piglets with diarrhoea and oedema disease. The limits of detection for F18common, F18ab, F18ac, and F18new variant were 10(7), 10(7), 10(5) and 10(7)colony forming units/g faeces, respectively. Of 94 Korean isolates of E. coli encoding F18, 70 were F18ac (43 STEC/ETEC, 4 STEC and 23 ETEC), 15 were F18ab (all STEC) and nine were F18new variant (1 STEC/ETEC, 7 STEC, 1 ETEC). PMID:23992871

  10. Subtilase cytotoxin-encoding subAB2 variants in verotoxin-producing Escherichia coli strains isolated from goats and sheep.

    PubMed

    Orden, José A; Domínguez-Bernal, Gustavo; de la Fuente, Ricardo; Carrión, Javier

    2016-04-01

    Subtilase cytotoxin (SubAB) is a cytotoxin which might contribute to the virulence of verotoxin-producing Escherichia coli (VTEC) strains in humans. Three variants of SubAB encoding genes have been described (subAB1, subAB2-1, and subAB2-2) and it has been suggested that the strains positive for two variants of subAB may be more pathogenic for humans. In this study, 188 subAB2-positive VTEC strains isolated from goats and sheep were investigated for the presence of the subAB2-1 and subAB2-2 variants by PCR. Eighty-one of the 132 (61.4%) caprine strains and 36 of the 56 (64.3%) ovine strains possessed the subAB2-1 variant and all ovine and caprine strains, except one, were positive for the subAB2-2 variant. The results of this study show for first time that the subAB2-1 and subAB2-2 variants are found in caprine subAB2-positive VTEC strains and confirm that both subAB2 variants are detected in ovine subAB2-positive VTEC strains. Since no significant difference in the presence of both subAB2 variants was found among strains belonging to serotypes associated with severe illness in humans and strains not belonging to these serotypes, the occurrence of two subAB2 variants seems not to be associated with a higher risk of severe disease in humans. PMID:27033912

  11. Subgroup J Avian Leukosis Virus Neutralizing Antibody Escape Variants Contribute to Viral Persistence in Meat-Type Chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have previously demonstrated a high incidence of chickens with persistent viremia even in the presence of neutralizing antibodies (NAb) against the inoculated parental virus (V+A+) in commercial meat-type chickens inoculated at hatch with Subgroup J avian leukosis virus (ALV J) field isolates. I...

  12. Glycoprotein-Specific Antibodies Produced by DNA Vaccination Protect Guinea Pigs from Lethal Argentine and Venezuelan Hemorrhagic Fever

    PubMed Central

    Golden, Joseph W.; Maes, Piet; Kwilas, Steven A.; Ballantyne, John

    2016-01-01

    ABSTRACT Several members of the Arenaviridae can cause acute febrile diseases in humans, often resulting in lethality. The use of convalescent-phase human plasma is an effective treatment in humans infected with arenaviruses, particularly species found in South America. Despite this, little work has focused on developing potent and defined immunotherapeutics against arenaviruses. In the present study, we produced arenavirus neutralizing antibodies by DNA vaccination of rabbits with plasmids encoding the full-length glycoprotein precursors of Junín virus (JUNV), Machupo virus (MACV), and Guanarito virus (GTOV). Geometric mean neutralizing antibody titers, as measured by the 50% plaque reduction neutralization test (PRNT50), exceeded 5,000 against homologous viruses. Antisera against each targeted virus exhibited limited cross-species binding and, to a lesser extent, cross-neutralization. Anti-JUNV glycoprotein rabbit antiserum protected Hartley guinea pigs from lethal intraperitoneal infection with JUNV strain Romero when the antiserum was administered 2 days after challenge and provided some protection (∼30%) when administered 4 days after challenge. Treatment starting on day 6 did not protect animals. We further formulated an IgG antibody cocktail by combining anti-JUNV, -MACV, and -GTOV antibodies produced in DNA-vaccinated rabbits. This cocktail protected 100% of guinea pigs against JUNV and GTOV lethal disease. We then expanded on this cocktail approach by simultaneously vaccinating rabbits with a combination of plasmids encoding glycoproteins from JUNV, MACV, GTOV, and Sabia virus (SABV). Sera collected from rabbits vaccinated with the combination vaccine neutralized all four targets. These findings support the concept of using a DNA vaccine approach to generate a potent pan-arenavirus immunotherapeutic. IMPORTANCE Arenaviruses are an important family of emerging viruses. In infected humans, convalescent-phase plasma containing neutralizing antibodies can

  13. Loss of adjuvanticity in rats for the hyperacute form of allergic encephalomyelitis and for reaginic antibody production in mice of a phenotypic variant of Bordetella pertussis.

    PubMed Central

    Wardlaw, A C; Parton, R; Bergman, R K; Munoz, J J

    1979-01-01

    The adjuvanticity of a phenotypic (C-mode) variant of B. pertussis, known to be deficient in certain immunological and physiopathological properties, was compared to that of the normal (X-mode) strain. The X-mode vaccine was a potent adjuvant for induction of hyperacute experimental allergic encephalomyelitis to guinea-pig spinal cord in Lewis rats whereas C-mode vaccine was inactive. X-mode vaccine was also highly active in the induction of reaginic (both IgE and IgGl) antibodies to ovalbumin in mice while C-mode vaccine caused only a transitory increase in the IgE level. These data support the view that an adjuvant component of B. pertussis, which is probably identical with the histamine-sensitizing and leukocytosis promoting factor, is much diminished in C-mode cells while the lipopolysaccharide adjuvant remains unchanged. PMID:500113

  14. Do vitamin D levels affect antibody titers produced in response to HPV vaccine?

    PubMed Central

    Zimmerman, Richard K; Lin, Chyongchiou Jeng; Raviotta, Jonathan M; Nowalk, Mary Patricia

    2015-01-01

    In addition to its well-known effects on bone metabolism, vitamin D is an immunomodulating hormone. Serum vitamin D levels in males 18–25 years were measured at baseline, and HPV antibody titers were measured one month following the third quadrivalent HPV vaccine dose. Vitamin D levels were ≥30 ng/ml (normal) in 60 males and <30 ng/ml (low) in 113 males. Reverse cumulative distribution curves and scatter plots showed higher antibody titers with low vitamin D for all vaccine strains (P < 0.05). In linear regression analyses, antibody titers for all HPV strains were significantly higher among those with lower vitamin D levels and among younger participants (P < 0.05). These relationships add to the body of knowledge of the complex role of vitamin D in immunoregulation. PMID:26176493

  15. A cytotoxic humanized anti-ganglioside antibody produced in a murine cell line defective of N-glycolylated-glycoconjugates.

    PubMed

    Fernández-Marrero, Yuniel; Roque-Navarro, Lourdes; Hernández, Tays; Dorvignit, Denise; Molina-Pérez, Marively; González, Addys; Sosa, Katya; López-Requena, Alejandro; Pérez, Rolando; de Acosta, Cristina Mateo

    2011-12-01

    Gangliosides containing the N-glycolyl (NGc) form of sialic acid are tumor-associated antigens and promising candidates for cancer therapy. We previously generated the murine 14F7 monoclonal antibody (mAb), specific for the N-glycolyl-GM3 ganglioside (NGcGM3), which induced an oncosis-like type of cell death on malignant cell lines expressing this antigen and recognized breast carcinoma by immunoscintigraphy in cancer patients. As humanization is expected to enhance its use for human cancer therapy, herein we describe the design and generation of two humanized versions of the 14F7 mAb by disrupting potential human T cell epitopes on its variable region. No differences in antigen reactivity or cytotoxic properties were detected among the variants tested and with respect to the chimeric counterpart. Humanized 14F7 genes were transfected into the NGcGM3-expressing NS0 cell line. Therefore, in the industrial scaling-up of the transfectoma in serum-free medium, cell viability was lost due to the cytotoxic effect of the secreted antibody. This shortcoming was solved by knocking down the CMP-N-acetylneuraminic acid hydroxylase enzyme, thus impairing the synthesis of NGc-glycoconjugates. Humanized 14F7 mAb is of potential value for the therapy of NGcGM3-expressing tumors. PMID:21802167

  16. Evaluation of recombinant transferrin-binding protein B variants from Neisseria meningitidis for their ability to induce cross-reactive and bactericidal antibodies against a genetically diverse collection of serogroup B strains.

    PubMed Central

    Rokbi, B; Mignon, M; Maitre-Wilmotte, G; Lissolo, L; Danve, B; Caugant, D A; Quentin-Millet, M J

    1997-01-01

    Transferrin-binding protein B (TbpB) is a surface-exposed protein, variable among strains of Neisseria meningitidis, that has been considered as a vaccine candidate. To define a TbpB molecule that would give rise to broadly cross-reactive antibodies with TbpB of many strains, specific antisera were produced against three recombinant TbpB variants from strain M982: one corresponding to the full-length TbpB; one in which stretches of amino acids located in the central part of the molecule, described as hypervariable, have been deleted; and one corresponding to the N-terminal half of the molecule, described as the human transferrin binding domain. The reactivity of these antisera against 58 serogroup B strains with a 2.1-kb tbpB gene representing different genotypes, serotypes, and subtypes and different geographic origins was tested on intact meningococcal cells. In parallel, the bactericidal activity of the antisera was evaluated against 15 of the 58 strains studied. Of the 58 strains, 56 (98%) reacted with the antiserum specific for the N-terminal half of TbpB M982; this antiserum was bactericidal against 9 of 15 strains (60%). On the other hand, 43 of 58 strains reacted with the antiserum raised to full-length TbpB while 12 of 15 (80%) were killed with this antiserum. The antiserum specific to TbpB deleted of its central domain gave intermediate results, with 53 of 58 strains (91.3%) recognized and 10 of 15 (66.6%) killed. These results indicate that the N-terminal half of TbpB was sufficient to induce cross-reactive antibodies reacting with the protein on meningococcal cells but that the presence of the C-terminal half of the protein is necessary for the induction of cross-bactericidal antibodies. PMID:8975892

  17. Relevance of biallelic versus monoallelic TNFRSF13B mutations in distinguishing disease-causing from risk-increasing TNFRSF13B variants in antibody deficiency syndromes

    PubMed Central

    Salzer, Ulrich; Bacchelli, Chiara; Buckridge, Sylvie; Pan-Hammarström, Qiang; Jennings, Stephanie; Lougaris, Vassilis; Bergbreiter, Astrid; Hagena, Tina; Birmelin, Jennifer; Plebani, Alessandro; Webster, A. David B.; Peter, Hans-Hartmut; Suez, Daniel; Chapel, Helen; McLean-Tooke, Andrew; Spickett, Gavin P.; Anover-Sombke, Stephanie; Ochs, Hans D.; Urschel, Simon; Belohradsky, Bernd H.; Ugrinovic, Sanja; Kumararatne, Dinakantha S.; Lawrence, Tatiana C.; Holm, Are M.; Franco, Jose L.; Schulze, Ilka; Schneider, Pascal; Gertz, E. Michael; Schäffer, Alejandro A.; Hammarström, Lennart; Thrasher, Adrian J.; Gaspar, H. Bobby

    2009-01-01

    TNFRSF13B encodes transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), a B cell– specific tumor necrosis factor (TNF) receptor superfamily member. Both biallelic and monoallelic TNFRSF13B mutations were identified in patients with common variable immunodeficiency disorders. The genetic complexity and variable clinical presentation of TACI deficiency prompted us to evaluate the genetic, immunologic, and clinical condition in 50 individuals with TNFRSF13B alterations, following screening of 564 unrelated patients with hypogammaglobulinemia. We identified 13 new sequence variants. The most frequent TNFRSF13B variants (C104R and A181E; n = 39; 6.9%) were also present in a heterozygous state in 2% of 675 controls. All patients with biallelic mutations had hypogammaglobulinemia and nearly all showed impaired binding to a proliferation-inducing ligand (APRIL). However, the majority (n = 41; 82%) of the pa-tients carried monoallelic changes in TNFRSF13B. Presence of a heterozygous mutation was associated with antibody deficiency (P <.001, relative risk 3.6). Heterozygosity for the most common mutation, C104R, was associated with disease (P < .001, relative risk 4.2). Furthermore, heterozygosity for C104R was associated with low numbers of IgD−CD27+ B cells (P = .019), benign lymphoproliferation (P < .001), and autoimmune complications (P = .001). These associations indicate that C104R heterozygosity increases the risk for common variable immunodeficiency disorders and influences clinical presentation. PMID:18981294

  18. Conserved epitopes on the hemagglutinin-neuraminidase proteins of human and bovine parainfluenza type 3 viruses: nucleotide sequence analysis of variants selected with monoclonal antibodies.

    PubMed Central

    Coelingh, K J; Winter, C C; Murphy, B R; Rice, J M; Kimball, P C; Olmsted, R A; Collins, P L

    1986-01-01

    We have previously identified 11 epitopes located in two topologically nonoverlapping antigenic sites (A and B) and a third bridging site (C) on the human type 3 parainfluenza virus (PIV3) hemagglutinin-neuraminidase (HN) glycoprotein by using monoclonal antibodies (MAbs) which inhibit hemagglutination and virus infectivity (K. L. Coelingh, C. C. Winter, and B. R. Murphy, Virology 143:569-582, 1985). We have identified three additional antigenic sites (D, E, and F) on the HN molecule by competitive-binding assays of anti-HN MAbs which have no known biological activity. Epitopes in sites A, D, and F are conserved on the bovine PIV3 HN glycoprotein and also among a wide range of human isolates. The dideoxy method was used to identify nucleotide substitutions in the HN genes of antigenic variants selected with neutralizing MAbs representing epitopes in site A which are shared by human and bovine PIV3. The deduced amino acid substitutions in the variants were located in separate hydrophilic stretches of HN residues which are conserved in the primary structures of the HN proteins of both human and bovine PIV3 strains. Images PMID:2427750

  19. A Variant of GJD2, Encoding for Connexin 36, Alters the Function of Insulin Producing β-Cells

    PubMed Central

    Cigliola, Valentina; Populaire, Celine; Pierri, Ciro L.; Deutsch, Samuel; Haefliger, Jacques-Antoine; Fadista, João; Lyssenko, Valeriya; Groop, Leif; Rueedi, Rico; Thorel, Fabrizio; Herrera, Pedro Luis; Meda, Paolo

    2016-01-01

    Signalling through gap junctions contributes to control insulin secretion and, thus, blood glucose levels. Gap junctions of the insulin-producing β-cells are made of connexin 36 (Cx36), which is encoded by the GJD2 gene. Cx36-null mice feature alterations mimicking those observed in type 2 diabetes (T2D). GJD2 is also expressed in neurons, which share a number of common features with pancreatic β-cells. Given that a synonymous exonic single nucleotide polymorphism of human Cx36 (SNP rs3743123) associates with altered function of central neurons in a subset of epileptic patients, we investigated whether this SNP also caused alterations of β-cell function. Transfection of rs3743123 cDNA in connexin-lacking HeLa cells resulted in altered formation of gap junction plaques and cell coupling, as compared to those induced by wild type (WT) GJD2 cDNA. Transgenic mice expressing the very same cDNAs under an insulin promoter revealed that SNP rs3743123 expression consistently lead to a post-natal reduction of islet Cx36 levels and β-cell survival, resulting in hyperglycemia in selected lines. These changes were not observed in sex- and age-matched controls expressing WT hCx36. The variant GJD2 only marginally associated to heterogeneous populations of diabetic patients. The data document that a silent polymorphism of GJD2 is associated with altered β-cell function, presumably contributing to T2D pathogenesis. PMID:26959991

  20. Functional characterization of the recombinant HIV-neutralizing monoclonal antibody 2F5 produced in maize seeds.

    PubMed

    Sabalza, M; Madeira, L; van Dolleweerd, C; Ma, J K; Capell, T; Christou, P

    2012-11-01

    Monoclonal antibodies (mAbs) that neutralize human immunodeficiency virus (HIV) can be used as microbicides to help prevent the spread of HIV in human populations. As an industry standard, HIV-neutralizing mAbs are produced as recombinant proteins in mammalian cells, but the high manufacturing costs and limited capacity reduce the ability of target populations in developing countries to gain access to these potentially life-saving medicines. Plants offer a more cost-effective and deployable production platform because they can be grown inexpensively and on a large scale in the region where the products are required. Here we show that the maize-derived HIV-neutralizing mAb 2F5 is assembled correctly in planta and binds to its antigen with the same affinity as 2F5 produced in mammalian cells. Although 2F5 has been produced at high levels in non-plant platforms, the yield in maize seeds is lower than previously achieved with another HIV-neutralizing mAb, 2G12. This suggests that the intrinsic properties of the antibody (e.g. sensitivity to specific proteases) and the environment provided by the production host (e.g. the relative abundance of different proteases, potential transgene silencing) may combine to limit the accumulation of some antibodies on a case-by-case basis. PMID:22965278

  1. Harnessing the immune system's arsenal: producing human monoclonal antibodies for therapeutics and investigating immune responses.

    PubMed

    Sullivan, Meghan; Kaur, Kaval; Pauli, Noel; Wilson, Patrick C

    2011-01-01

    Monoclonal antibody technology has undergone rapid and innovative reinvention over the last 30 years. Application of these technologies to human samples revealed valuable therapeutic and experimental insights. These technologies, each with their own benefits and flaws, have proven indispensable for immunological research and in our fight to provide new treatments and improved vaccines for infectious disease. PMID:21876728

  2. A cell sorter with modified bamboo charcoal for the efficient selection of specific antibody-producing hybridomas.

    PubMed

    Lin, Chien-Chen; Ni, Mei-Hui; Chang, Yu-Chung; Yeh, Hsiu-Lun; Lin, Feng-Huei

    2010-11-01

    Monoclonal antibodies (mAbs) have been proven useful in research and clinical applications. However, the generation of mAbs by conventional hybridoma technology is time-, cost- and labor-consuming. Here we developed a simplified procedure for efficient generation and selection of antibody-producing hybridomas within 1 h, using a particular cell sorter design, a cytoflow reactor-based cell sorter (CBCS) which consists mainly of the "cytoflow reactor" that comprises two components, a reaction chamber and a glass tubing for air and medium exchange by gravity, and the "sorting material", human EGFR-conjugated bamboo charcoal, for specific B-cell enrichment. The high surface area and porous structure of bamboo charcoal greatly increased cell density and protein production. Moreover, from Raman, FT-IR spectroscopy and IFA analysis, the carboxylation and immobilization of bamboo charcoal can be introduced easily by nitric acid treatment and conjugated handily with human EGFR using EDC/NHS. Other evidences, such as IFA, showed that the specific hybridomas generated in this study could secrete specific anti-human EGFR antibodies. Our design allows the production of mAbs while avoiding time-consuming steps, such as large numbers of limiting dilutions and screening assays, and demonstrates that the CBCS could be a powerful tool for monoclonal antibody production. PMID:20708791

  3. Detailed functional characterization of glycosylated and nonglycosylated variants of malaria vaccine candidate PfAMA1 produced in Nicotiana benthamiana and analysis of growth inhibitory responses in rabbits.

    PubMed

    Boes, Alexander; Spiegel, Holger; Edgue, Gueven; Kapelski, Stephanie; Scheuermayer, Matthias; Fendel, Rolf; Remarque, Edmond; Altmann, Friedrich; Maresch, Daniel; Reimann, Andreas; Pradel, Gabriele; Schillberg, Stefan; Fischer, Rainer

    2015-02-01

    One of the most promising malaria vaccine candidate antigens is the Plasmodium falciparum apical membrane antigen 1 (PfAMA1). Several studies have shown that this blood-stage antigen can induce strong parasite growth inhibitory antibody responses. PfAMA1 contains up to six recognition sites for N-linked glycosylation, a post-translational modification that is absent in P. falciparum. To prevent any potential negative impact of N-glycosylation, the recognition sites have been knocked out in most PfAMA1 variants expressed in eukaryotic hosts. However, N-linked glycosylation may increase efficacy by improving immunogenicity and/or focusing the response towards relevant epitopes by glycan masking. We describe the production of glycosylated and nonglycosylated PfAMA1 in Nicotiana benthamiana and its detailed characterization in terms of yield, integrity and protective efficacy. Both PfAMA1 variants accumulated to high levels (>510 μg/g fresh leaf weight) after transient expression, and high-mannose-type N-glycans were confirmed for the glycosylated variant. No significant differences between the N. benthamiana and Pichia pastoris PfAMA1 variants were detected in conformation-sensitive ligand-binding studies. Specific titres of >2 × 10(6) were induced in rabbits, and strong reactivity with P. falciparum schizonts was observed in immunofluorescence assays, as well as up to 100% parasite growth inhibition for both variants, with IC₅₀ values of ~35 μg/mL. Competition assays indicated that a number of epitopes were shielded from immune recognition by N-glycans, warranting further studies to determine how glycosylation can be used for the directed targeting of immune responses. These results highlight the potential of plant transient expression systems as a production platform for vaccine candidates. PMID:25236489

  4. Specific recognition pattern of IgM and IgG antibodies produced in the course of experimental paracoccidioidomycosis.

    PubMed Central

    Vaz, C A; Mackenzie, D W; Hearn, V M; Camargo, Z P; Singer-Vermes, L M; Burger, E; Calich, V L

    1992-01-01

    Specific IgM and IgG responses to Paracoccidioides brasiliensis produced in resistant and susceptible mice during experimental paracoccidioidomycosis were examined by the immunoblotting procedure. Sera from infected mice recognized 51 antigen bands with apparent molecular masses from 8 to 86 kD. Sixteen of these were defined as major antigen bands because of almost universal presence of antibodies to them, and their intense staining. All sera, including those from normal control mice, tested for both IgM and IgG antibody reacted with the major E antigen which appeared as a large diffuse band from 43 to 47 kD. Comparisons between resistant and susceptible mice showed some significant differences in IgM responses to many antigen bands. While IgG responses were quite similar for both strains, differences were apparent in the response to the antigens at 62 and 68 kD. Images Fig. 1 Fig. 2 Fig. 3 PMID:1563097

  5. Enzyme-labeled Antigen Method: Development and Application of the Novel Approach for Identifying Plasma Cells Locally Producing Disease-specific Antibodies in Inflammatory Lesions

    PubMed Central

    Mizutani, Yasuyoshi; Shiogama, Kazuya; Onouchi, Takanori; Sakurai, Kouhei; Inada, Ken-ichi; Tsutsumi, Yutaka

    2016-01-01

    In chronic inflammatory lesions of autoimmune and infectious diseases, plasma cells are frequently observed. Antigens recognized by antibodies produced by the plasma cells mostly remain unclear. A new technique identifying these corresponding antigens may give us a breakthrough for understanding the disease from a pathophysiological viewpoint, simply because the immunocytes are seen within the lesion. We have developed an enzyme-labeled antigen method for microscopic identification of the antigen recognized by specific antibodies locally produced in plasma cells in inflammatory lesions. Firstly, target biotinylated antigens were constructed by the wheat germ cell-free protein synthesis system or through chemical biotinylation. Next, proteins reactive to antibodies in tissue extracts were screened and antibody titers were evaluated by the AlphaScreen method. Finally, with the enzyme-labeled antigen method using the biotinylated antigens as probes, plasma cells producing specific antibodies were microscopically localized in fixed frozen sections. Our novel approach visualized tissue plasma cells that produced 1) autoantibodies in rheumatoid arthritis, 2) antibodies against major antigens of Porphyromonas gingivalis in periodontitis or radicular cyst, and 3) antibodies against a carbohydrate antigen, Strep A, of Streptococcus pyogenes in recurrent tonsillitis. Evaluation of local specific antibody responses expectedly contributes to clarifying previously unknown processes in inflammatory disorders. PMID:27006517

  6. An In Vitro Combined Antibiotic-Antibody Treatment Eliminates Toxicity from Shiga Toxin-Producing Escherichia coli

    PubMed Central

    Skinner, Craig; Zhang, Guodong; Patfield, Stephanie

    2015-01-01

    Treating Shiga toxin-producing Escherichia coli (STEC) gastrointestinal infections is difficult. The utility of antibiotics for STEC treatment is controversial, since antibiotic resistance among STEC isolates is widespread and certain antibiotics dramatically increase the expression of Shiga toxins (Stxs), which are some of the most important virulence factors in STEC. Stxs contribute to life-threatening hemolytic uremic syndrome (HUS), which develops in considerable proportions of patients with STEC infections. Understanding the antibiotic resistance profiles of STEC isolates and the Stx induction potential of promising antibiotics is essential for evaluating any antibiotic treatment of STEC. In this study, 42 O157:H7 or non-O157 STEC isolates (including the “big six” serotypes) were evaluated for their resistance against 22 antibiotics by using an antibiotic array. Tigecycline inhibited the growth of all of the tested STEC isolates and also inhibited the production of Stxs (Stx2 in particular). In combination with neutralizing antibodies to Stx1 and Stx2, the tigecycline-antibody treatment fully protected Vero cells from Stx toxicity, even when the STEC bacteria and the Vero cells were cultured together. The combination of an antibiotic such as tigecycline with neutralizing antibodies presents a promising strategy for future STEC treatments. PMID:26100707

  7. Antibody-integrated and functionalized graphite-encapsulated magnetic beads, produced using ammonia gas plasma technology, for capturing Salmonella.

    PubMed

    Sakudo, Akikazu; Chou, Han; Nagatsu, Masaaki

    2015-03-01

    Salmonella spp. is the single and most important causative agent of foodborne infections, especially involving foods such as eggs, milk and meat. To prevent infection, a reliable surveillance system is required that can quickly and sensitively detect Salmonella. Here, we describe the development of antibody-integrated magnetic beads that are functionalized by a novel strategy using ammonia gas plasma. Ammonia plasma, produced by a radio frequency (RF) power supply, was allowed to react with the surface of graphite-encapsulated magnetic beads, resulting in the introduction of amino groups. An anti-Salmonella antibody was then anchored by sulfide groups present on the protein surface to the amino groups of the magnetic beads via N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP). The potential usefulness of these magnetic beads for capturing Salmonella was examined as follows. The beads were incubated with Salmonella in liquid medium and then separated from the supernatant by applying a magnetic field. After thorough washing, adsorption of Salmonella to the beads was confirmed by immunochromatography, polymerase chain reaction and a direct culture assay. Our findings indicate that the capture and concentration of Salmonella using the antibody-integrated magnetic beads was more efficient than commercial Dynabeads® anti-Salmonella, which are conventionally used for concentrating Salmonella from liquid cultures. We believe this novel bead technology will contribute to the enhanced detection of Salmonella. PMID:25660257

  8. A novel plant-produced Pfs25 fusion subunit vaccine induces long-lasting transmission blocking antibody responses

    PubMed Central

    Jones, R Mark; Chichester, Jessica A; Manceva, Slobodanka; Gibbs, Sandra K; Musiychuk, Konstantin; Shamloul, Moneim; Norikane, Joey; Streatfield, Stephen J; van de Vegte-Bolmer, Marga; Roeffen, Will; Sauerwein, Robert W; Yusibov, Vidadi

    2014-01-01

    Malaria transmission blocking vaccines (TBV) directed against proteins expressed on sexual stages of Plasmodium falciparum in the mosquito midgut are considered an effective means to reduce malaria transmission. Antibodies induced by TBV block sporogonic development in the mosquito, and thus transmission to the next human host. The Pfs25 protein, expressed on the surface of gametes, zygotes and ookinetes, is one of the primary targets for TBV development. Using a plant virus-based transient expression system, we have successfully produced Pfs25 fused to a modified lichenase (LicKM) carrier in Nicotiana benthamiana, purified and characterized the protein (Pfs25-FhCMB), and evaluated this vaccine candidate in animal models for the induction of transmission blocking antibodies. Soluble Pfs25-FhCMB was expressed in plants at a high level, and induced transmission blocking antibodies that persisted for up to 6 months post immunization in mice and rabbits. These data demonstrate the potential of the new malaria vaccine candidate and also support feasibility of expressing Plasmodium antigens in a plant-based system. PMID:25483525

  9. Monoclonal neutralizing antibodies against EV71 screened from mice immunized with yeast-produced virus-like particles.

    PubMed

    Lin, Tao; Xianyu, Lingzhi; Lyu, Songya

    2015-06-01

    Periodic outbreaks of hand, foot and mouth disease (HFMD) occur in children under 5 years old, and can cause death in some cases. The C4 strain of enterovirus 71 (EV71) is the main pathogen that causes HFMD in China. Although no drugs against EV71 are available, some studies have shown that candidate vaccines or viral capsid proteins can produce anti-EV71 immunity. In this study, female BABL/c mice (6-8 weeks old) were immunized with virus-like particles (VLPs) of EV71 produced in yeast to screen for anti-EV71 antibodies. Two hybridomas that could produce neutralizing antibodies against EV71 were obtained. Both neutralizing mAbs (D4 and G12) were confirmed to bind the VP1 capsid protein of EV71, and could protect >95% cells from 100 TCID50 EV71 infection at 25 µg/mL solution (lowest concentration). Those two neutralizing mAbs identified in the study may be promising candidates in development for mAbs to treat EV71 infection, and utilized as suitable reagents for use in diagnostic tests and biological studies. PMID:26040893

  10. Structural insight in the inhibition of adherence of F4 fimbriae producing enterotoxigenic Escherichia coli by llama single domain antibodies.

    PubMed

    Moonens, Kristof; Van den Broeck, Imke; Okello, Emmanuel; Pardon, Els; De Kerpel, Maia; Remaut, Han; De Greve, Henri

    2015-01-01

    Enterotoxigenic Escherichia coli that cause neonatal and post-weaning diarrhea in piglets express F4 fimbriae to mediate attachment towards host receptors. Recently we described how llama single domain antibodies (VHHs) fused to IgA, produced in Arabidopsis thaliana seeds and fed to piglets resulted in a progressive decline in shedding of F4 positive ETEC bacteria. Here we present the structures of these inhibiting VHHs in complex with the major adhesive subunit FaeG. A conserved surface, distant from the lactose binding pocket, is targeted by these VHHs, highlighting the possibility of targeting epitopes on single-domain adhesins that are non-involved in receptor binding. PMID:25828907

  11. Antibody-producing cells correlated to body weight in juvenile chinook salmon (Oncorhynchus tshawytscha) acclimated to optimal and elevated temperatures

    USGS Publications Warehouse

    Harrahy, L.N.M.; Schreck, C.B.; Maule, A.G.

    2001-01-01

    The immune response of juvenile chinook salmon (Oncorhynchus tshawytscha) ranging in weight from approximately 10 to 55 g was compared when the fish were acclimated to either 13 or 21?? C. A haemolytic plaque assay was conducted to determine differences in the number of antibody-producing cells (APC) among fish of a similar age but different body weights. Regression analyses revealed significant increases in the number of APC with increasing body weight when fish were acclimated to either water temperature. These results emphasise the importance of standardising fish weight in immunological studies of salmonids before exploring the possible effects of acclimation temperatures. ?? 2001 Academic Press.

  12. Age-related prevalence of cross-reactive antibodies against influenza A(H3N2) variant virus, Germany, 2003 to 2010.

    PubMed

    Blümel, B; Schweiger, B; Dehnert, M; Buda, S; Reuss, A; Czogiel, I; Kamtsiuris, P; Schlaud, M; Poethko-Müller, C; Thamm, M; Haas, W

    2015-01-01

    To estimate susceptibility to the swine-origin influenza A(H3N2) variant virus (A(H3N2)v) in the German population, we investigated cross-reactive antibodies against this virus and factors associated with seroprotective titre using sera from representative health examination surveys of children and adolescents (n = 815, 2003–06) and adults (n = 600, 2008–10). Antibodies were assessed by haemagglutination inhibition assay (HI); in our study an HI titre ≥ 40 was defined as seroprotective. We investigated associated factors by multivariable logistic regression. Overall, 41% (95% confidence interval (CI): 37–45) of children and adolescents and 39% (95% CI: 34–44) of adults had seroprotective titres. The proportion of people with seroprotective titre was lowest among children younger than 10 years (15%; 95% CI: 7–30) and highest among adults aged 18 to 29 years (59%; 95% CI: 49–67). Prior influenza vaccination was associated with higher odds of having seroprotective titre (odds ratio (OR) for children and adolescents: 3.4; 95% CI: 1.8–6.5; OR for adults: 2.4; 95% CI: 1.7–3.4). Young children showed the highest and young adults the lowest susceptibility to the A(H3N2)v virus. Our results suggest that initial exposure to circulating seasonal influenza viruses may predict long-term cross-reactivity that may be enhanced by seasonal influenza vaccination. PMID:26290488

  13. Natural killer cells produce T cell-recruiting chemokines in response to antibody-coated tumor cells.

    PubMed

    Roda, Julie M; Parihar, Robin; Magro, Cynthia; Nuovo, Gerard J; Tridandapani, Susheela; Carson, William E

    2006-01-01

    In the current report, we have examined the ability of natural killer (NK) cells to produce T cell-recruiting chemokines following dual stimulation with interleukin (IL)-2 or IL-12 and human breast cancer cells coated with an antitumor antibody (trastuzumab). NK cells stimulated in this manner secreted an array of T cell-recruiting chemotactic factors, including IL-8, macrophage-derived chemokine, macrophage inflammatory protein 1alpha (MIP-1alpha), monocyte chemoattractant protein 1, and regulated on activation, normal T-cell expressed and secreted (RANTES), whereas stimulation of NK cells with either agent alone had minimal effect. Furthermore, these factors were functional for T-cell chemotaxis as culture supernatants derived from costimulated NK cells induced migration of both naïve and activated T cells in an in vitro chemotaxis assay. T-cell migration was significantly reduced when neutralizing antibodies to IL-8, MIP-1alpha, or RANTES were added to culture supernatants before their use in the chemotaxis assay. In addition, coadministration of trastuzumab-coated tumor cells and IL-12 to mice led to enhanced serum MIP-1alpha. As a clinical correlate, we examined the chemokine content of serum samples from breast cancer patients enrolled on a phase I trial of trastuzumab and IL-12, and found elevated levels of IL-8, RANTES, IFN-gamma inducible protein 10, monokine induced by IFN-gamma, and MIP-1alpha, specifically in those patients that experienced a clinical benefit. Sera from these patients exhibited the ability to direct T-cell migration in a chemotaxis assay, and neutralization of chemokines abrogated this effect. These data are the first to show chemokine production by NK cells, specifically in response to stimulation with antibody-coated tumor cells, and suggest a potential role for NK cell-derived chemokines in patients receiving therapeutic monoclonal antibodies. PMID:16397268

  14. Human Circulating Antibody-Producing B Cell as a Predictive Measure of Mucosal Immunity to Poliovirus

    PubMed Central

    Verma, Harish; Sharma, Prashant; Yang, Jae Seung; Saletti, Giulietta; Ahmad, Mohammad; Bahl, Sunil K.; Wierzba, Thomas F.; Nandy, Ranjan K.; Deshpande, Jagadish M.; Sutter, Roland W.; Czerkinsky, Cecil

    2016-01-01

    Background The “gold standard” for assessing mucosal immunity after vaccination with poliovirus vaccines consists in measuring virus excretion in stool after challenge with oral poliovirus vaccine (OPV). This testing is time and resource intensive, and development of alternative methods is a priority for accelerating polio eradication. We therefore evaluated circulating antibody-secreting cells (ASCs) as a potential means to evaluate mucosal immunity to poliovirus vaccine. Methods 199 subjects, aged 10 years, and previously immunized repeatedly with OPV, were selected. Subjects were assigned to receive either a booster dose of inactivated poliovirus vaccine (IPV), bivalent OPV (bOPV), or no vaccine. Using a micro-modified whole blood-based ELISPOT assay designed for field setting, circulating poliovirus type-specific IgA- and IgG-ASCs, including gut homing α4β7+ ASCs, were enumerated on days 0 and 7 after booster immunization. In addition, serum samples collected on days 0, 28 and 56 were tested for neutralizing antibody titers against poliovirus types 1, 2, and 3. Stool specimens were collected on day 28 (day of bOPV challenge), and on days 31, 35 and 42 and processed for poliovirus isolation. Results An IPV dose elicited blood IgA- and IgG-ASC responses in 84.8 to 94.9% of subjects, respectively. In comparison, a bOPV dose evoked corresponding blood ASC responses in 20.0 to 48.6% of subjects. A significant association was found between IgA- and IgG-ASC responses and serum neutralizing antibody titers for poliovirus type 1, 2, 3 (p<0.001). In the IPV group, α4β7+ ASCs accounted for a substantial proportion of IgA-ASCs and the proportion of subjects with a positive α4β7+ IgA-ASC response to poliovirus types 1, 2 and 3 was 62.7%, 89.8% and 45.8%, respectively. A significant association was observed between virus excretion and α4β7+ IgA- and/or IgG-ASC responses to poliovirus type 3 among immunized children; however, only a weak association was found for

  15. [Transverse myelitis associated with toxocariasis and the importance of locally produced antibodies for diagnosis].

    PubMed

    Ural, Serap; Özer, Behiye; Gelal, Fazıl; Dirim Erdoğan, Derya; Sezak, Nurbanu; Balık, Recep; Demirdal, Tuna; Korkmaz, Metin

    2016-07-01

    Toxocariasis caused by Toxocara canis or less frequently by T.catis is a common parasitic infection worldwide. Clinical spectrum in humans can vary from asymptomatic infection to serious organ disfunction depending on the load of parasite, migration target of the larva and the inflammatory response of the host. Transverse myelitis (TM) due to toxocariasis is an uncommon illness identified mainly as case reports in literature. In this report, a case of TM who was diagnosed as neurotoxocariasis by serological findings has been presented. A 44-year-old male patient complained with backache was diagnosed as TM in a medical center in which he has admitted two years ago, and treated with pregabalin and nonsteroidal drugs for six months. Because of the progression of the lesions he readmitted to another center and treated with high dose steroid therapy for three months. After six months of follow up, improvement has been achieved, however, since his symptoms reccurred in the following year he was admitted to our hospital. Magnetic resonance imaging (MRI) examination revealed a TM in a lower segment of spinal cord. He was suffering with weakness and numbness in the left lower extremity. There was no history of rural life or contact with cats or dogs in his anamnesis. Physical examination revealed normal cranial nerve functions, sensory and motor functions. There has been no pathological reflexes, and deep tendon reflexes were also normal. Laboratory findings yielded normal hemogram and biochemical tests, negative PPD and parasitological examination of stool were negative for cysts and ova. Viral hepatitis markers, anti-HIV, toxoplasma-IgM, CMV-IgM, rubella-IgM, EBV-VCA-IgM, VDRL, Brucella tube agglutination, echinococcus antibody, autoantibody tests and neuromyelitis optica test were negative. Examination of CSF showed 20 cells/mm3 (mononuclear cells), 45 mg/dl protein and normal levels of glucose and chlorine. In both serum and CSF samples of the patient Toxocara

  16. Marginal zone B cells: virtues of innatelike antibody-producing lymphocytes

    PubMed Central

    Cerutti, Andrea; Cols, Montserrat; Puga, Irene

    2013-01-01

    Protective responses to microorganisms involve the nonspecific but rapid defence mechanisms of the innate immune system, followed by the specific but slow defence mechanisms of the adaptive immune system. Located as sentinels at the interface between the circulation and lymphoid tissue, splenic marginal zone B cells rapidly respond to blood-borne antigens by adopting ‘crossover’ defensive strategies that blur the conventional boundaries of innate and adaptive immunity. This Review discusses how marginal zone B cells function as innate-like lymphocytes that mount rapid antibody responses to both T cell-dependent and T cell-independent antigens. These responses require the integration of activation signals from germline-encoded and somatically recombined receptors for microorganisms with helper signals from effector cells of the innate and adaptive immune systems. PMID:23348416

  17. Selection of monoclonal antibodies for the identification of D variants: ability to detect weak D and to split epD2, epD5 and epD6/7.

    PubMed

    Jones, J; Filbey, D

    1996-01-01

    Red cells from known D variant donors were tested with 41 monoclonal anti-D reagents, 26 IgG and 15 IgM, with the view to selecting a panel to aid the identification of unusual D types. These antibodies gave reaction patterns which allowed the identification of most of the known D category cells, recognizing epD2, epD5, epD6/7, epD8 and epD9, but were unable to distinguish category III from normal D-positive cells. Reactivity with HMi, HMii, DFR, DBT and RoHar cells split epD2, epD5 and epD6/7 into two, three and eight groups, respectively. A panel comprising 15 monoclonal anti-D, 11 IgG and four IgM, was selected as representative of the antibodies tested. Reactivity of monoclonal anti-D was dependent on antibody concentration and antibody avidity. An antibody concentration of at least 12 micrograms/ml was required for optimum reactivity of the two monoclonal antibodies tested. A simple calculation of division of the titre by the antibody concentration provided a relatively simple means of establishing the reactivity performance of the antibody and correlated well with ability to detect weak D (Du) cells. A characteristic variable reduction in reaction strength with all the IgG anti-D was observed with weak D cells. The IgM antibodies, except the high avidity RUM-1, T3D2T6, D9A4 and BS226, performed poorly in detecting weak D. The majority of the IgM antibodies tested reacted with RoHarr cells, while only one IgG antibody was positive. PMID:8740011

  18. Neutralization of Clostridium difficile Toxin B Mediated by Engineered Lactobacilli That Produce Single-Domain Antibodies

    PubMed Central

    Andersen, Kasper Krogh; Strokappe, Nika M.; Hultberg, Anna; Truusalu, Kai; Smidt, Imbi; Mikelsaar, Raik-Hiio; Mikelsaar, Marika; Verrips, Theo; Hammarström, Lennart

    2015-01-01

    Clostridium difficile is the primary cause of nosocomial antibiotic-associated diarrhea in the Western world. The major virulence factors of C. difficile are two exotoxins, toxin A (TcdA) and toxin B (TcdB), which cause extensive colonic inflammation and epithelial damage manifested by episodes of diarrhea. In this study, we explored the basis for an oral antitoxin strategy based on engineered Lactobacillus strains expressing TcdB-neutralizing antibody fragments in the gastrointestinal tract. Variable domain of heavy chain-only (VHH) antibodies were raised in llamas by immunization with the complete TcdB toxin. Four unique VHH fragments neutralizing TcdB in vitro were isolated. When these VHH fragments were expressed in either secreted or cell wall-anchored form in Lactobacillus paracasei BL23, they were able to neutralize the cytotoxic effect of the toxin in an in vitro cell-based assay. Prophylactic treatment with a combination of two strains of engineered L. paracasei BL23 expressing two neutralizing anti-TcdB VHH fragments (VHH-B2 and VHH-G3) delayed killing in a hamster protection model where the animals were challenged with spores of a TcdA− TcdB+ strain of C. difficile (P < 0.05). Half of the hamsters in the treated group survived until the termination of the experiment at day 5 and showed either no damage or limited inflammation of the colonic mucosa despite having been colonized with C. difficile for up to 4 days. The protective effect in the hamster model suggests that the strategy could be explored as a supplement to existing therapies for patients. PMID:26573738

  19. Neutralization of Clostridium difficile Toxin B Mediated by Engineered Lactobacilli That Produce Single-Domain Antibodies.

    PubMed

    Andersen, Kasper Krogh; Strokappe, Nika M; Hultberg, Anna; Truusalu, Kai; Smidt, Imbi; Mikelsaar, Raik-Hiio; Mikelsaar, Marika; Verrips, Theo; Hammarström, Lennart; Marcotte, Harold

    2016-02-01

    Clostridium difficile is the primary cause of nosocomial antibiotic-associated diarrhea in the Western world. The major virulence factors of C. difficile are two exotoxins, toxin A (TcdA) and toxin B (TcdB), which cause extensive colonic inflammation and epithelial damage manifested by episodes of diarrhea. In this study, we explored the basis for an oral antitoxin strategy based on engineered Lactobacillus strains expressing TcdB-neutralizing antibody fragments in the gastrointestinal tract. Variable domain of heavy chain-only (VHH) antibodies were raised in llamas by immunization with the complete TcdB toxin. Four unique VHH fragments neutralizing TcdB in vitro were isolated. When these VHH fragments were expressed in either secreted or cell wall-anchored form in Lactobacillus paracasei BL23, they were able to neutralize the cytotoxic effect of the toxin in an in vitro cell-based assay. Prophylactic treatment with a combination of two strains of engineered L. paracasei BL23 expressing two neutralizing anti-TcdB VHH fragments (VHH-B2 and VHH-G3) delayed killing in a hamster protection model where the animals were challenged with spores of a TcdA(-) TcdB(+) strain of C. difficile (P < 0.05). Half of the hamsters in the treated group survived until the termination of the experiment at day 5 and showed either no damage or limited inflammation of the colonic mucosa despite having been colonized with C. difficile for up to 4 days. The protective effect in the hamster model suggests that the strategy could be explored as a supplement to existing therapies for patients. PMID:26573738

  20. Induction of antihemagglutinin antibodies by polyclonal antiidiotype antibodies.

    PubMed

    Dinca, L; Neuwirth, S; Schulman, J; Bona, C

    1993-01-01

    Antiidiotypic antibodies can be envisioned as an alternative approach in the development of vaccines against influenza virus, which exhibits natural antigenic variations. In our work, we obtained two polyclonal cross-reactive anti-Id antibodies against PY102, VM113, and VM202 mAbs, which in turn are specific respectively for PR8 virus and laboratory-induced virus variants (PY102-V1 and VM113-V1). With these cross-reactive anti-Id antibodies, we were able to elicit anti-HA antibodies in mice. In comparing the anti-HA antibody response in animals injected with anti-Id antibodies to those immunized with PR8 influenza virus, we demonstrated that the HI titer was higher after virus immunization and that the PR8 virus boost was more efficient in this group. Our results showed that the polyclonal cross-reactive anti-Id antibodies were more efficient than the individual anti-Ids at eliciting responses. At the same time, we demonstrated that PR8-primed T cells, cultured with B cells from animals immunized with anti-Id antibodies, were able to produce anti-PR8 antibodies subsequent to stimulation with influenza virus. PMID:8476510

  1. Successful treatment of TAFRO syndrome, a variant type of multicentric Castleman disease with thrombotic microangiopathy, with anti-IL-6 receptor antibody and steroids.

    PubMed

    Fujiwara, Shiho; Mochinaga, Hiromi; Nakata, Hirotomo; Ohshima, Koichi; Matsumoto, Masanori; Uchiba, Mitsuhiro; Mikami, Yoshiki; Hata, Hiroyuki; Okuno, Yutaka; Mitsuya, Hiroaki; Nosaka, Kisato

    2016-06-01

    TAFRO syndrome is a rare variant type of multicentric Castleman disease, which is characterized by thrombocytopenia, anasarca, reticulin fibrosis of bone marrow, renal dysfunction and organomegaly. Here, we report a case of TAFRO syndrome that was successfully treated with tocilizumab. A 50-year-old man, who presented with fever, epigastric pain, abdominal fullness, and massive edema of the extremities, was admitted to our hospital. Computed tomography revealed bilateral pleural effusions, ascites, and lymphadenopathy. Laboratory data showed renal dysfunction, anemia, and thrombocytopenia. Examination of bone marrow and cervical lymph nodes led to a diagnosis of hyaline vascular-type Castleman disease. The level of serum interleukin (IL)-6 was extremely high. TAFRO syndrome was finally diagnosed. The patient was treated weekly with tocilizumab, an anti-IL-6 receptor antibody and steroids. In 4 weeks, all symptoms disappeared and serum IL-6 level returned to normal. Activity of ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), which was significantly decreased (9.9 %) prior to treatment, increased after treatment with tocilizumab. The present case suggests that tocilizumab is an effective therapeutic agent for TAFRO syndrome. We suggest that hypercytokinemia in TAFRO syndrome inhibits ADAMTS13 activity, thereby inducing thrombotic microangiopathy. PMID:26980221

  2. Clonal frequency analysis of B cells producing pathogenic anti-DNA antibody-associated idiotypes in systemic lupus erythematosus.

    PubMed

    Shibata, S; Sasaki, T; Hatakeyama, A; Munakata, Y; Hirabayashi, Y; Yoshinaga, K

    1992-06-01

    In order to identify the mechanism responsible for autoantibody production in systemic lupus erythematosus (SLE), B cell repertoires associated with anti-DNA idiotypes were explored by a limiting dilution analysis using Epstein-Barr virus (EBV) transformation methods and ELISA spot assays. The frequencies of B cell clones producing antibodies to DNA and to conventional antigens, tetanus toxoid, dinitrophenyl, or keyhole limpet hemocyanin were higher in active SLE compared to those in inactive SLE and in normal subjects. In addition, there was a disproportionate increase in anti-DNA antibody- and anti-DNA idiotype (Id)-producing clones at the precursor cell levels as well as at the mature cell level. On the other hand, numbers of anti-Id clones against anti-DNA-Id, termed 0-81 Id, were markedly increased at inactive stages of the disease but not at active stages. These were confirmed by serial studies in some patients with SLE. These results support a two-step mechanism for autoantibody production, in which initial polyclonal activation is followed by an antigen-driven process, and indicate an alteration of the precursor B cell repertoire in SLE, which may also associate with a preferential expansion of anti-DNA clones. PMID:1320474

  3. Scaled-up manufacturing of recombinant antibodies produced by plant cells in a 200-L orbitally-shaken disposable bioreactor.

    PubMed

    Raven, Nicole; Rasche, Stefan; Kuehn, Christoph; Anderlei, Tibor; Klöckner, Wolf; Schuster, Flora; Henquet, Maurice; Bosch, Dirk; Büchs, Jochen; Fischer, Rainer; Schillberg, Stefan

    2015-02-01

    Tobacco BY-2 cells have emerged as a promising platform for the manufacture of biopharmaceutical proteins, offering efficient protein secretion, favourable growth characteristics and cultivation in containment under a controlled environment. The cultivation of BY-2 cells in disposable bioreactors is a useful alternative to conventional stainless steel stirred-tank reactors, and orbitally-shaken bioreactors could provide further advantages such as simple bag geometry, scalability and predictable process settings. We carried out a scale-up study, using a 200-L orbitally-shaken bioreactor holding disposable bags, and BY-2 cells producing the human monoclonal antibody M12. We found that cell growth and recombinant protein accumulation were comparable to standard shake flask cultivation, despite a 200-fold difference in cultivation volume. Final cell fresh weights of 300-387 g/L and M12 yields of ∼20 mg/L were achieved with both cultivation methods. Furthermore, we established an efficient downstream process for the recovery of M12 from the culture broth. The viscous spent medium prevented clarification using filtration devices, but we used expanded bed adsorption (EBA) chromatography with SP Sepharose as an alternative for the efficient capture of the M12 antibody. EBA was introduced as an initial purification step prior to protein A affinity chromatography, resulting in an overall M12 recovery of 75-85% and a purity of >95%. Our results demonstrate the suitability of orbitally-shaken bioreactors for the scaled-up cultivation of plant cell suspension cultures and provide a strategy for the efficient purification of antibodies from the BY-2 culture medium. PMID:25117428

  4. Large scale cultivation of an anti-D (IgM) antibody producing human/mouse heterohybridoma.

    PubMed

    Fizil, A; Hencsey, Z; Veszely, G; Inzelt-Kovács, M; Bánkúti, L

    1996-01-01

    A human/mouse heterohybridoma cell line secreting anti-Rh(D) antibody was established by the fusion of Epstein-Barr Virus (EBV) transformed human B lymphocytes and human/mouse heteromyelomas. During scaling-up the cell line was adapted to suspension culture, then medium composition was gradually altered into a more economical one. The adapted cell line has kept its multiplication and antibody secreting characteristics in the new medium. Parameters of large scale batch cultivation in bioreactors were optimized in working volume of 3.6 litre and production was carried out under these parameters in working volume of 24 litre. Optimized parameters were the follows: (i) the cell line is highly sensitive to dissolved oxygen (DO) level, its optimal DO is 10%; (ii) optimal inoculum cell count is 3 x 10(5) cell/ml; (iii) Marine-blade impeller was chosen for supporting the requested oxygen transfer. Using the optimized parameters HUMAN Co. Ltd. produces the Monoclonal Anti-D (IgM) reagent, which has been registered in 1995 in Hungary and now it is on the market. PMID:9147726

  5. Binding specificities of eight monoclonal antibodies to human glycophorin A - studies with M/sup c/M, and M/sub k/En(UK) variant human erythrocytes and M- and MN/sup V/-type chimpanzee erythrocytes

    SciTech Connect

    Bigbee, W.L.; Langlois, R.G.; Vanderlaan, M.; Jensen, R.H.

    1984-12-01

    Four newly derived mouse monoclonal antibodies to human glycophorin A are described. Three of these antibodies bind preferentially to the N form of glycophorin A; the fourth recognizes a shared determinant of the M and N forms. All four antibodies are directed toward the 39 amino acid, amino-terminal portion of the protein, and the N-specific antibodies require for binding the presence of N-acetyl-neuraminic acid on the glycosidically linked oligosaccharides. Cross-reaction of the N-specific antibodies to homozygous MM erythrocytes appears to result from binding to glycophorin B. In addition, these antibodies together with four previously reported glycophorin monoclonal antibodies, including two that specifically recognize the M form of glycophorin A, were tested for binding to M/sup c/M and M/sup k/En(UK) variant human erythrocytes. Results obtained for five of the six M- or N-specific monoclonal antibodies point to the general immunodominance of the amino-terminal serine-leucine polymorphism and the requirement for sialic acid. The epitopes for all three N-specific monoclonal antibodies include the amino terminal leucine that occurs in the N form of glycophorin A and may also include the glutamic acid that occurs at position five. Their studies support the proposed Lepore-type glycophorin A-B hybrid gene rearrangement for the En(UK) allele found in the English En(a-) family. The data also confirm the expression of the M-like glycoprotein on chimpanzee erythrocytes and the presence of a human glycophorin B-like antigen on the MN/sup V/-type cells.

  6. Yeast-produced recombinant virus-like particles of coxsackievirus A6 elicited protective antibodies in mice.

    PubMed

    Zhou, Yu; Shen, Chaoyun; Zhang, Chao; Zhang, Wei; Wang, Lili; Lan, Ke; Liu, Qingwei; Huang, Zhong

    2016-08-01

    Coxsackievirus A6 (CA6) has recently emerged as the predominant pathogen of hand, foot and mouth disease (HFMD), causing significant morbidity in children and adults. The increasing prevalence of CA6 infection and its associated disease burden underscore the need for effective CA6 vaccines. However, CA6 grows poorly in cultured cells, making it difficult to develop inactivated whole-virus or live attenuated vaccines. Here we report the development of a recombinant virus-like particle (VLP) based CA6 vaccine. CA6 VLPs were produced in Pichia pastoris yeast transformed with a vector encoding both P1 and 3CD proteins of CA6. Immunization with CA6 VLPs elicited CA6-specific serum antibodies in mice. Passive transfer of anti-VLP antisera protected recipient mice against lethal CA6 challenge. Collectively, these results demonstrate that CA6 VLPs represent a viable CA6 vaccine candidate which warrants further preclinical and clinical development. PMID:27315772

  7. Identification of Point Mutations in Clinical Staphylococcus aureus Strains That Produce Small-Colony Variants Auxotrophic for Menadione

    PubMed Central

    Dean, Melissa A.; Olsen, Randall J.; Long, S. Wesley; Rosato, Adriana E.

    2014-01-01

    Staphylococcus aureus small-colony variants (SCVs) are implicated in chronic and relapsing infections that are difficult to diagnose and treat. Despite many years of study, the underlying molecular mechanisms and virulence effect of the small-colony phenotype remain incompletely understood. We sequenced the genomes of five S. aureus SCV strains recovered from human patients and discovered previously unidentified nonsynonymous point mutations in three genes encoding proteins in the menadione biosynthesis pathway. Analysis of genetic revertants and complementation with wild-type alleles confirmed that these mutations caused the SCV phenotype and decreased virulence for mice. PMID:24452687

  8. Effect of a Conjugate of Daunomycin and Antibodies to Rat α -fetoprotein on the Growth of α -fetoprotein-Producing Tumor Cells

    NASA Astrophysics Data System (ADS)

    Tsukada, Y.; Bischof, W. K.-D.; Hibi, N.; Hirai, H.; Hurwitz, E.; Sela, M.

    1982-01-01

    Daunomycin was covalently attached via a dextran bridge to specific antibodies against rat α -fetoprotein produced in a horse. The effect of this conjugate on an α -fetoprotein-producing tumor was investigated in terms of cytotoxicity and inhibition or retardation of tumor development. Under the experimental conditions used, the covalent conjugate was by both criteria more efficient than either daunomycin alone or a mixture of daunomycin and specific antibodies or a conjugate of daunomycin with horse immunoglobulin. These results show that the conjugate may be useful as a specific cytotoxic agent against α -fetoprotein-producing tumors.

  9. Cell lines for the production of monoclonal antibodies to human glycophorin A

    DOEpatents

    Bigbee, William L.; Fong, Stella S. N.; Jensen, Ronald H.; Vanderlaan, Martin; Langlois, Richard G.

    1988-01-01

    Cloned mouse hybridoma cell lines have been established which continuously produce antibodies that differentiate between the M and N forms of human glycophorin A. These antibodies have potential application as human blood group reagents, as markers for terminally differentiated erythroid cells and as immunofluorescent labels of somatically variant human erythrocytes.

  10. Cell lines for the production of monoclonal antibodies to human glycophorin A

    SciTech Connect

    Bigbee, W.L.; Fong, S.S.N.; Jensen, R.H.; Vanderlaan, M.; Langlois, R.G.

    1988-08-30

    Cloned mouse hybridoma cell lines have been established which continuously produce antibodies that differentiate between the M and N forms of human glycophorin A. These antibodies have potential application as human blood group reagents, as markers for terminally differentiated erythroid cells and as immunofluorescent labels of somatically variant human erythrocytes.

  11. Method and cell lines for the production of monoclonal antibodies to human glycophorin A

    DOEpatents

    Bigbee, W.L.; Fong, S.S.N.; Jensen, R.H.; Vanderlaan, M.

    Cloned mouse hybridoma cell lines have been established which continuously produce antibodies that differentiate between the M and N forms of human glycophorin A. These antibodies have potential application as human blood group reagents, as markers for terminally differentiated erythroid cells and as immunofluorescent labels of somatically variant human erythrocytes.

  12. Serum anti-tissue transglutaminase antibodies detected during febrile illness may not be produced by the intestinal mucosa.

    PubMed

    De Leo, Luigina; Quaglia, Sara; Ziberna, Fabiana; Vatta, Serena; Martelossi, Stefano; Maschio, Massimo; Not, Tarcisio

    2015-03-01

    Anti-transglutaminase antibodies are the diagnostic marker of celiac disease, and are considered to be synthesized only by intestinal B-lymphocytes. During an infectious disease, these antibodies are transiently detected in serum. We show that these infection-triggered antibodies may not originate in the intestinal mucosa and are not an indication of celiac disease. PMID:25722272

  13. Ethanol and Reactive Species Increase Basal Sequence Heterogeneity of Hepatitis C Virus and Produce Variants with Reduced Susceptibility to Antivirals

    PubMed Central

    Seronello, Scott; Montanez, Jessica; Presleigh, Kristen; Barlow, Miriam; Park, Seung Bum; Choi, Jinah

    2011-01-01

    Hepatitis C virus (HCV) exhibits a high level of genetic variability, and variants with reduced susceptibility to antivirals can occur even before treatment begins. In addition, alcohol decreases efficacy of antiviral therapy and increases sequence heterogeneity of HCV RNA but how ethanol affects HCV sequence is unknown. Ethanol metabolism and HCV infection increase the level of reactive species that can alter cell metabolism, modify signaling, and potentially act as mutagen to the viral RNA. Therefore, we investigated whether ethanol and reactive species affected the basal sequence variability of HCV RNA in hepatocytes. Human hepatoma cells supporting a continuous replication of genotype 1b HCV RNA (Con1, AJ242652) were exposed to ethanol, acetaldehyde, hydrogen peroxide, or L-buthionine-S,R-sulfoximine (BSO) that decreases intracellular glutathione as seen in patients. Then, NS5A region was sequenced and compared with genotype 1b HCV sequences in the database. Ethanol and BSO elevated nucleotide and amino acid substitution rates of HCV RNA by 4–18 folds within 48 hrs which were accompanied by oxidative RNA damage. Iron chelator and glutathione ester decreased both RNA damage and mutation rates. Furthermore, infectious HCV and HCV core gene were sufficient to induce oxidative RNA damage even in the absence of ethanol or BSO. Interestingly, the dn/ds ratio and percentage of sites undergoing positive selection increased with ethanol and BSO, resulting in an increased detection of NS5A variants with reduced susceptibility to interferon alpha, cyclosporine, and ribavirin and others implicated in immune tolerance and modulation of viral replication. Therefore, alcohol is likely to synergize with virus-induced oxidative/nitrosative stress to modulate the basal mutation rate of HCV. Positive selection induced by alcohol and reactive species may contribute to antiviral resistance. PMID:22087316

  14. AHNP-Streptavidin: A Tetrameric Bacterially Produced Antibody Surrogate Fusion Protein Against p185her2/neu

    SciTech Connect

    Masuda,K.; Richter, M.; Song, X.; Berezov, A.; Masuda, K.; Murali, R.; Greene, M.; Zhang, H.

    2006-01-01

    The anti-p185her2/neu peptidomimetic (AHNP) is a small exo-cyclic peptide derived from the anti-p185her2/neu rhumAb 4D5 (h4D5). AHNP mimics many but not all of the antitumor characteristics exhibited by h4D5. However, the pharmacokinetic profiles of AHNP are less than optimal for therapeutic or diagnostic purposes. To improve the binding affinity to p185her2/neu and the antitumor efficacy, we have engineered a fusion protein containing AHNP and a nonimmunoglobulin protein scaffold, streptavidin (SA). The recombinant protein, AHNP-SA (ASA) bound to p185her2/neu with high affinity, inhibited the proliferation of p185her2/neu-overexpressing cells, and reduced tumor growth induced by p185her2/neu-transformed cells. These data suggest that the bacterially produced tetrameric ASA can be used as an antibody-surrogate molecule. This class of molecule will play a role in the diagnosis and treatment of p185her2/neu-related tumors. Our studies establish a general principle by which a small biologically active synthetic exo-cyclic peptide can be engineered to enhance functional aspects by structured oligomerization and can be produced recombinantly using bacterial expression.

  15. Preparation of Specific Polyclonal Antibody Against the Recombinant Mutacin Produced by sfGFP Fusion Protein Technology

    PubMed Central

    Al-Homsi, Lamis; Al-Okla, Souad; Abbady, Abdul Q.

    2015-01-01

    Mutacin I, a bacteriocin produced by streptococcus mutans, displays an antimicrobial activity against many gram positive and some gram negative bacteria. Because of its medical importance, production of this short peptide in large scale for future applications is a significant challenge. This work described the improvement of a novel system to produce the recombinant mutacin using fusion protein technology. The short peptide was expressed directly as a fusion protein with a superfolder form of the green florescent protein (sfGFP), resulting in a high yield expression of soluble sfGFP-mutacin fusion protein (30 kDa) in the cytoplasm of E. coli. Mutacin was released from the fusion by enzymatic cleavage at the tobacco etch virus (TEV) protease recognition site and separated from the carrier sfGFP by nickel affinity and gel filtration chromatography. An additional advantage of this fusion system was tested in the generation of mutacin-specific polyclonal antibodies. Specific anti-mutacin IgGs were affinity purified, and were able to recognize the mutacin-sfGFP fusion protein or the cleaved forms of mutacin. Even though it was efficiently produced (25 mg/L) by this method, pure mutacin was devoid of antibiotic activity. Fourier transform infrared spectroscopy (FTIR) analysis revealed the absence of thioether bonds in the purified mutacin, which are critical for final structure and function of this antibiotic. Determining whether the activity of pure mutacin could be recovered by the reformation of such structures by chemical reaction needs more investigations. The development of this system will provide large quantities of mutacin for future studies and applications as broad spectrum antibacterial peptide. PMID:26668664

  16. Labeling Internalizing Anti-Epidermal Growth Factor Receptor Variant III Monoclonal Antibody with 177Lu: In Vitro Comparison of Acyclic and Macrocyclic Ligands

    PubMed Central

    Hens, Marc; Vaidyanathan, Ganesan; Welsh, Phil; Zalutsky, Michael R.

    2009-01-01

    Introduction The monoclonal antibody (mAb) L8A4, reactive with the epidermal growth factor receptor variant III (EGFRvIII), internalizes rapidly in glioma cells after receptor binding. Combining this tumor specific mAb with the low energy β-emitter 177Lu would be an attractive approach for brain tumor radioimmunotherapy, provided that trapping of the radionuclide in tumor cells after mAb intracellular processing could be maximized. Materials and Methods L8A4 mAb was labeled with 177Lu using the acyclic ligands [(R)-2-Amino-3-(4-isothiocyanatophenyl)propyl]-trans-(S,S)-cyclohexane-1,2-diamine-pentaacetic acid (CHX-A″-DTPA), 2-(4-Isothiocyanatobenzyl)-diethylenetriaminepenta-acetic acid (pSCN-Bz-DTPA), and 2-(4-Isothiocyanatobenzyl)-6-methyldiethylenetriaminepentaacetic acid (1B4M-DTPA) and the macrocyclic ligands S-2-(4-Isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-tetraacetic acid (C-DOTA) and α-(5-isothiocyanato-2-methoxyphenyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (MeO-DOTA). Paired-label internalization and cellular processing assays were performed on EGFRvIII-expressing U87.ΔEGFR glioma cells over 24-h to directly compare 177Lu-labeled L8A4 to L8A4 labeled with 125I using either Iodogen or N-succinimidyl 4-guanidinomethyl-3-[125I]iodobenzoate ([125I]SGMIB). In order to facilitate comparison of labeling methods, the primary parameter evaluated was the ratio of 177Lu to 125I activity retained in U87.ΔEGFR cells. Results All chelates demonstrated higher retention of internalized activity compared with mAb labeled using Iodogen, with 177Lu/125I ratios of >20 observed for the 3 DTPA chelates at 24 h. When compared to L8A4 labeled using SGMIB, except for MeO-DOTA, internalized activity for 125I was higher than 177Lu from 1–8 h with the opposite behavior observed thereafter. At 24 h, 177Lu/125I ratios were between 1.5 and 3, with higher values observed for the 3 DTPA chelates. Conclusions The nature of the chelate used to label this

  17. Monoclonal antibodies produced in BALB.B10 mice define new antigenic determinants in culture filtrate preparations of Mycobacterium tuberculosis.

    PubMed Central

    Worsaae, A; Ljungqvist, L; Heron, I

    1988-01-01

    A panel of monoclonal antibodies were derived from BALB.B10 mice immunized with a culture filtrate from Mycobacterium tuberculosis H37Rv. Of these antibodies, 10 were examined more closely for antigen specificity and interspecies reactivity. Six antibodies were used as immunosorbents for affinity purification of their corresponding antigens. Two monoclonal antibodies (HBT 2 and HBT 11) reacted with a 17-kilodalton antigen, and a competition assay showed that these antibodies are directed against the same epitope or against epitopes that are sterically very close to each other. Monoclonal antibody HBT 12 reacted with the same molecule with which a previously described 38-kilodalton reactive antibody reacted but was directed against a different epitope. Antibody HBT 10 reacted with a culture filtrate of M. tuberculosis but not of Mycobacterium bovis BCG. This latter finding was further studied by testing different preparations of M. tuberculosis H37Rv antigens and, additionally, culture filtrates of four M. tuberculosis and two BCG strains. Interspecies reactivity was assayed by immunoblotting and revealed that the majority of the monoclonal antibodies were specific to M. tuberculosis complex. Images PMID:2466047

  18. A high-throughput approach to identify genomic variants of bacterial metabolite producers at the single-cell level.

    PubMed

    Binder, Stephan; Schendzielorz, Georg; Stäbler, Norma; Krumbach, Karin; Hoffmann, Kristina; Bott, Michael; Eggeling, Lothar

    2012-01-01

    We present a novel method for visualizing intracellular metabolite concentrations within single cells of Escherichia coli and Corynebacterium glutamicum that expedites the screening process of producers. It is based on transcription factors and we used it to isolate new L-lysine producing mutants of C. glutamicum from a large library of mutagenized cells using fluorescence-activated cell sorting (FACS). This high-throughput method fills the gap between existing high-throughput methods for mutant generation and genome analysis. The technology has diverse applications in the analysis of producer populations and screening of mutant libraries that carry mutations in plasmids or genomes. PMID:22640862

  19. A high-throughput approach to identify genomic variants of bacterial metabolite producers at the single-cell level

    PubMed Central

    2012-01-01

    We present a novel method for visualizing intracellular metabolite concentrations within single cells of Escherichia coli and Corynebacterium glutamicum that expedites the screening process of producers. It is based on transcription factors and we used it to isolate new L-lysine producing mutants of C. glutamicum from a large library of mutagenized cells using fluorescence-activated cell sorting (FACS). This high-throughput method fills the gap between existing high-throughput methods for mutant generation and genome analysis. The technology has diverse applications in the analysis of producer populations and screening of mutant libraries that carry mutations in plasmids or genomes. PMID:22640862

  20. Human ecalectin, a variant of human galectin-9, is a novel eosinophil chemoattractant produced by T lymphocytes.

    PubMed

    Matsumoto, R; Matsumoto, H; Seki, M; Hata, M; Asano, Y; Kanegasaki, S; Stevens, R L; Hirashima, M

    1998-07-01

    A 1.6-kilobase pair cDNA was isolated from a human T-cell-derived expression library that encodes a novel eosinophil chemoattractant (designated ecalectin) expressed during allergic and parasitic responses. Based on its deduced amino acid sequence, ecalectin is a 36-kDa protein consisting of 323 amino acids. Although ecalectin lacks a hydrophobic signal peptide, it is secreted from mammalian cells. Ecalectin is not related to any known cytokine or chemokine but rather is a variant of human galectin-9, a member of the large family of animal lectins that have affinity for beta-galactosides. Recombinant ecalectin, expressed in COS cells and insect cells, exhibited potent eosinophil chemoattractant activity and attracted eosinophils in vitro and in vivo in a dose-dependent manner but not neutrophils, lymphocytes, or monocytes. The finding that the ecalectin transcript is present in abundance in various lymphatic tissues and that its expression increases substantially in antigen-activated peripheral blood mononuclear cells suggests that ecalectin is an important T-cell-derived regulator of eosinophil recruitment in tissues during inflammatory reactions. We believe that this is the first report of the expression of an immunoregulatory galectin expressed by a T-cell line that is selective for eosinophils. PMID:9642261

  1. CEACAM6 as detected by the AP11 antibody is a marker notable for mucin-producing adenocarcinomas.

    PubMed

    Lee, Ok-Jun; Son, Seung-Myoung; Hong, Kwon Pyo; Lee, Yong-Moon; Kim, Min-Young; Choi, Jae-Woon; Lee, Sang-Jeon; Song, Young-Jin; Kim, Hak Soon; Kim, Wun-Jae; Shin, See-Ok; Song, Hyung Geun

    2015-02-01

    A new monoclonal antibody recognizing CEACAM6, which we named AP11, was generated by immunizing BALB/c mice with phytohemagglutinin-activated human peripheral blood mononuclear cells. This study aims to evaluate whether CEACAM6 can serve as a tumor marker using AP11. We examined the expression of CEACAM6 with AP11 in 11 human carcinoma cell lines by flow cytometry and 439 human tissues including 282 tumor tissues and 157 normal tissues by immunohistochemistry. CEACAM6 epitope recognized by AP11 was well preserved in formalin-fixed and paraffin-embedded tissues. Adenocarcinomas of the stomach (86%), colorectum (95%), pancreas (100%), and lung (83%), urinary bladder (100%), and mucinous ovarian tumors (88%) had a high rate of CEACAM6 immunoreactivity. We observed a variable expression of CEACAM6 in hepatocellular carcinomas (35%), squamous cell carcinomas of the lung (60%), renal cell carcinomas (14%), urothelial carcinomas (13%), serous carcinomas of the ovary (17%), and breast carcinomas (11%). Small-cell carcinomas of the lung, prostatic adenocarcinomas, papillary thyroid carcinomas, malignant melanomas, giant cell tumors, and osteosarcomas were negative for CEACAM6. All normal tissues of various organs were negative for CEACAM6. In conclusion, CEACAM6 as detected by AP11, may serve as a marker for mucin-producing adenocarcinomas of the gastrointestinal tract and ovary as well as non-small cell lung cancer. Thus, AP11 represents a valuable diagnostic tool for detecting CEACMA6-positive cancers. PMID:25427744

  2. Relationship between target antigens and major histocompatibility complex (MHC) class II genes in producing two pathogenic antibodies simultaneously

    PubMed Central

    Zakka, L R; Keskin, D B; Reche, P; Ahmed, A R

    2010-01-01

    In this report, we present 15 patients with histological and immunopathologically proven pemphigus vulgaris (PV). After a mean of 80 months since the onset of disease, when evaluated serologically, they had antibodies typical of PV and pemphigoid (Pg). Similarly, 18 patients with bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP) were diagnosed on the basis of histology and immunopathology. After a mean of 60 months since the onset of disease, when their sera were evaluated they were found to have Pg and PV autoantibodies. In both groups of patients the diseases were characterized by a chronic course, which included several relapses and recurrences and were non-responsive to conventional therapy. The major histocompatibility complex class II (MHC II) genes were studied in both groups of patients and phenotypes associated typically with them were observed. Hence, in 33 patients, two different pathogenic autoantibodies were detected simultaneously. The authors provide a computer model to show that each MHC II gene has relevant epitopes that recognize the antigens associated with both diseases. Using the databases in these computer models, the authors present the hypothesis that these two autoantibodies are produced simultaneously due to the phenomena of epitope spreading. PMID:21069937

  3. Species- and infective stage-specific monoclonal antibodies to Leishmania major produced by an in vitro immunization method.

    PubMed

    Wu, S J; Rowton, E D; Ma, M; Andre, R G

    1990-12-01

    Monoclonal antibodies specific to the infective-stage promastigotes of Leishmania major are needed for developing rapid diagnostic assays of infected sand flies. An in vitro immunization protocol was applied for the production of monoclonal antibodies using small amounts of L. major. Infective-stage promastigotes were isolated from sand flies (Phlebotomus papatasi) 7-10 days after infection and used as antigen for immunization. Two weeks after a primary immunization, murine splenocytes were removed and immunized in vitro with antigen in murine EL-4 thymoma cell conditioned medium. Three fusions were performed using X63-Ag.653 myeloma cells as fusion partners and two fusions were performed using FOX-NY cells. Antibodies specific to promastigotes were detected using an indirect enzyme-linked immunosorbent assay (ELISA). Initially 56 monoclonal antibodies were selected, and their species and stage specificity were determined using both an ELISA and an indirect fluorescent antibody assay (IFA). Twelve monoclonal antibodies showed species specificity to L. major when tested against four sympatric species of Leishmania. Four other monoclonal antibodies showed species and infective-stage specificity to L. major promastigotes. When tested in immunoblots, all four species- and stage-specific monoclonal antibodies bound to five protein bands that were unique to the infective-stage promastigotes. PMID:2087235

  4. Naturally produced opsonizing antibodies restrict the survival of Mycobacterium tuberculosis in human macrophages by augmenting phagosome maturation

    PubMed Central

    Kumar, Shashi Kant; Singh, Padam; Sinha, Sudhir

    2015-01-01

    This study investigated the hypothesis that serum antibodies against Mycobacterium tuberculosis present in naturally infected healthy subjects of a tuberculosis (TB) endemic area could create and/or sustain the latent form of infection. All five apparently healthy Indian donors showed high titres of serum antibodies against M. tuberculosis cell membrane antigens, including lipoarabinomannan and alpha crystallin. Uptake and killing of bacilli by the donor macrophages was significantly enhanced following their opsonization with antibody-rich, heat-inactivated autologous sera. However, the capability to opsonize was apparent for antibodies against some and not other antigens. High-content cell imaging of infected macrophages revealed significantly enhanced colocalization of the phagosome maturation marker LAMP-1, though not of calmodulin, with antibody-opsonized compared with unopsonized M. tuberculosis. Key enablers of macrophage microbicidal action—proinflammatory cytokines (IFN-γ and IL-6), phagosome acidification, inducible NO synthase and nitric oxide—were also significantly enhanced following antibody opsonization. Interestingly, heat-killed M. tuberculosis also elevated these mediators to the levels comparable to, if not higher than, opsonized M. tuberculosis. Results of the study support the emerging view that an efficacious vaccine against TB should, apart from targeting cell-mediated immunity, also generate ‘protective’ antibodies. PMID:26674415

  5. Aging-dependent decline of IL-10 producing B cells coincides with production of antinuclear antibodies but not rheumatoid factors.

    PubMed

    van der Geest, Kornelis S M; Lorencetti, Pedro G; Abdulahad, Wayel H; Horst, Gerda; Huitema, Minke; Roozendaal, Caroline; Kroesen, Bart-Jan; Brouwer, Elisabeth; Boots, Annemieke M H

    2016-03-01

    Aging is associated with development of autoimmunity. Loss of B cell tolerance in the elderly is suggested by an increased prevalence of anti-nuclear antibodies (ANAs) and rheumatoid factors (RFs). Accumulating evidence indicates that B cells also impact autoimmunity via secretion of cytokines. So far, few studies have directly assessed the effect of aging on the latter B cell function. Here, we determined if and how human aging influences the production of cytokines by B cells. In a cross-sectional study, we found that absolute numbers of circulating B cells were similar in 31 young (ages 19-39) and 73 old (age ≥ 60) individuals. Numbers of transitional B cells (CD19(+)CD27(-)CD38(High)CD24(High)) were decreased in old individuals, whereas numbers of naive and memory B cell subsets were comparable in young and old individuals. Short-term in vitro stimulation of whole blood samples revealed that numbers of B cells capable of producing TNF-α were similar in young and old individuals. In contrast, B cells capable of IL-10 production were decreased in old subjects. This decline of IL-10(+) B cells was observed in old individuals that were ANA positive, and in those that were negative for both ANAs and RFs. However, IL-10(+) B cells were remarkably well retained in the circulation of old subjects that were RF positive. Thus, pro-inflammatory TNF-α(+) B cells are retained in the elderly, whereas IL-10(+) B cells generally decline. In addition, our findings indicate that IL-10(+) B cells may differentially impact the development of ANAs and RFs in the elderly. PMID:26721376

  6. Outbreak Caused by an Ertapenem-Resistant, CTX-M-15-Producing Klebsiella pneumoniae Sequence Type 101 Clone Carrying an OmpK36 Porin Variant

    PubMed Central

    Poulou, Aggeliki; Voulgari, Evangelia; Vrioni, Georgia; Koumaki, Vasiliki; Xidopoulos, Grigorios; Chatzipantazi, Vasiliki; Markou, Fani

    2013-01-01

    Although numerous studies have documented outbreaks of carbapenem-resistant Klebsiella pneumoniae (CRKP) possessing various carbapenemases, reports on outbreaks due to CRKP possessing extended-spectrum β-lactamases (ESBLs) and/or AmpCs with porin lesions have been limited. Here, we describe an outbreak caused by an ertapenem-resistant, CTX-M-15-producing clonal K. pneumoniae strain expressing an OmpK36 porin variant. From May 2012 to November 2012, 37 ertapenem-resistant K. pneumoniae isolates phenotypically negative for carbapenemase production were recovered from 19 patients hospitalized in the intensive care unit of a Greek hospital. The isolates were either susceptible or intermediate to other carbapenems and resistant to all remaining β-lactams but cefotetan. Phenotypic and molecular analysis revealed the presence in all isolates of the blaCTX-M-15 gene on a conjugative 100-kb plasmid, disruption in the expression of the ompK35 gene, and the production of an Ompk36 porin variant. The index case was a patient admitted from another hospital. Active surveillance upon admission and on a weekly basis was immediately initiated; environmental samples were also periodically tested. Molecular typing showed that all clinical isolates as well as two ertapenem-resistant environmental K. pneumoniae isolates belonged to the same clonal type and were assigned to multilocus sequence typing (MLST) sequence type 101 (ST101). As all colonized/infected patients were hospitalized during overlapping periods, cross-infection was considered the main route for the dissemination of the outbreak strain. Despite reinforcement of infection control measures and active surveillance, the outbreak lasted approximately 7 months. Identification of hidden carriers upon admission and by screening on a weekly basis was found valuable for early recognition and subsequent successful management of the outbreak. PMID:23850951

  7. Efficient In Vitro and In Vivo Activity of Glyco-Engineered Plant-Produced Rabies Monoclonal Antibodies E559 and 62-71-3

    PubMed Central

    Tsekoa, Tsepo Lebiletsa; Lotter-Stark, Therese; Buthelezi, Sindisiwe; Chakauya, Ereck; Stoychev, Stoyan H.; Sabeta, Claude; Shumba, Wonderful; Phahladira, Baby; Hume, Steve; Morton, Josh; Rupprecht, Charles E.; Steinkellner, Herta; Pauly, Michael; Zeitlin, Larry; Whaley, Kevin; Chikwamba, Rachel

    2016-01-01

    Rabies is a neglected zoonotic disease that has no effective treatment after onset of illness. However the disease can be prevented effectively by prompt administration of post exposure prophylaxis which includes administration of passive immunizing antibodies (Rabies Immune Globulin, RIG). Currently, human RIG suffers from many restrictions including limited availability, batch-to batch inconsistencies and potential for contamination with blood-borne pathogens. Anti-rabies monoclonal antibodies (mAbs) have been identified as a promising alternative to RIG. Here, we applied a plant-based transient expression system to achieve rapid, high level production and efficacy of the two highly potent anti-rabies mAbs E559 and 62-71-3. Expression levels of up to 490 mg/kg of recombinant mAbs were obtained in Nicotiana benthamiana glycosylation mutants by using a viral based transient expression system. The plant-made E559 and 62-71-3, carrying human-type fucose-free N-glycans, assembled properly and were structurally sound as determined by mass spectrometry and calorimetric density measurements. Both mAbs efficiently neutralised diverse rabies virus variants in vitro. Importantly, E559 and 62-71-3 exhibited enhanced protection against rabies virus compared to human RIG in a hamster model post-exposure challenge trial. Collectively, our results provide the basis for the development of a multi-mAb based alternative to RIG. PMID:27427976

  8. Efficient In Vitro and In Vivo Activity of Glyco-Engineered Plant-Produced Rabies Monoclonal Antibodies E559 and 62-71-3.

    PubMed

    Tsekoa, Tsepo Lebiletsa; Lotter-Stark, Therese; Buthelezi, Sindisiwe; Chakauya, Ereck; Stoychev, Stoyan H; Sabeta, Claude; Shumba, Wonderful; Phahladira, Baby; Hume, Steve; Morton, Josh; Rupprecht, Charles E; Steinkellner, Herta; Pauly, Michael; Zeitlin, Larry; Whaley, Kevin; Chikwamba, Rachel

    2016-01-01

    Rabies is a neglected zoonotic disease that has no effective treatment after onset of illness. However the disease can be prevented effectively by prompt administration of post exposure prophylaxis which includes administration of passive immunizing antibodies (Rabies Immune Globulin, RIG). Currently, human RIG suffers from many restrictions including limited availability, batch-to batch inconsistencies and potential for contamination with blood-borne pathogens. Anti-rabies monoclonal antibodies (mAbs) have been identified as a promising alternative to RIG. Here, we applied a plant-based transient expression system to achieve rapid, high level production and efficacy of the two highly potent anti-rabies mAbs E559 and 62-71-3. Expression levels of up to 490 mg/kg of recombinant mAbs were obtained in Nicotiana benthamiana glycosylation mutants by using a viral based transient expression system. The plant-made E559 and 62-71-3, carrying human-type fucose-free N-glycans, assembled properly and were structurally sound as determined by mass spectrometry and calorimetric density measurements. Both mAbs efficiently neutralised diverse rabies virus variants in vitro. Importantly, E559 and 62-71-3 exhibited enhanced protection against rabies virus compared to human RIG in a hamster model post-exposure challenge trial. Collectively, our results provide the basis for the development of a multi-mAb based alternative to RIG. PMID:27427976

  9. Regulatory approval and a first-in-human phase I clinical trial of a monoclonal antibody produced in transgenic tobacco plants.

    PubMed

    Ma, Julian K-C; Drossard, Jürgen; Lewis, David; Altmann, Friedrich; Boyle, Julia; Christou, Paul; Cole, Tom; Dale, Philip; van Dolleweerd, Craig J; Isitt, Valerie; Katinger, Dietmar; Lobedan, Martin; Mertens, Hubert; Paul, Mathew J; Rademacher, Thomas; Sack, Markus; Hundleby, Penelope A C; Stiegler, Gabriela; Stoger, Eva; Twyman, Richard M; Vcelar, Brigitta; Fischer, Rainer

    2015-10-01

    Although plant biotechnology has been widely investigated for the production of clinical-grade monoclonal antibodies, no antibody products derived from transgenic plants have yet been approved by pharmaceutical regulators for clinical testing. In the Pharma-Planta project, the HIV-neutralizing human monoclonal antibody 2G12 was expressed in transgenic tobacco (Nicotiana tabacum). The scientific, technical and regulatory demands of good manufacturing practice (GMP) were addressed by comprehensive molecular characterization of the transgene locus, confirmation of genetic and phenotypic stability over several generations of transgenic plants, and by establishing standard operating procedures for the creation of a master seed bank, plant cultivation, harvest, initial processing, downstream processing and purification. The project developed specifications for the plant-derived antibody (P2G12) as an active pharmaceutical ingredient (API) based on (i) the guidelines for the manufacture of monoclonal antibodies in cell culture systems; (ii) the draft European Medicines Agency Points to Consider document on quality requirements for APIs produced in transgenic plants; and (iii) de novo guidelines developed with European national regulators. From the resulting process, a GMP manufacturing authorization was issued by the competent authority in Germany for transgenic plant-derived monoclonal antibodies for use in a phase I clinical evaluation. Following preclinical evaluation and ethical approval, a clinical trial application was accepted by the UK national pharmaceutical regulator. A first-in-human, double-blind, placebo-controlled, randomized, dose-escalation phase I safety study of a single vaginal administration of P2G12 was carried out in healthy female subjects. The successful completion of the clinical trial marks a significant milestone in the commercial development of plant-derived pharmaceutical proteins. PMID:26147010

  10. Anti-ICOS Monoclonal Antibody MEDI-570 in Treating Patients With Relapsed or Refractory Peripheral T-cell Lymphoma Follicular Variant or Angioimmunoblastic T-cell Lymphoma

    ClinicalTrials.gov

    2016-09-08

    Follicular Variant Peripheral T-Cell Lymphoma; Recurrent Angioimmunoblastic T-cell Lymphoma; Recurrent Mature T- and NK-Cell Non-Hodgkin Lymphoma; Refractory Angioimmunoblastic T-cell Lymphoma; Refractory Mature T-Cell and NK-Cell Non-Hodgkin Lymphoma

  11. Capture of dengue viruses using antibody-integrated graphite-encapsulated magnetic beads produced using gas plasma technology

    PubMed Central

    SAKUDO, AKIKAZU; VISWAN, ANCHU; CHOU, HAN; SASAKI, TADAHIRO; IKUTA, KAZUYOSHI; NAGATSU, MASAAKI

    2016-01-01

    Despite significant advances in medicine, global health is threatened by emerging infectious diseases caused by a number of viruses. Dengue virus (DENV) is a mosquito-borne virus, which can be transmitted to humans via mosquito vectors. Previously, the Ministry of Health, Labour and Welfare in Japan reported the country's first domestically acquired case of dengue fever for almost 70 years. To address this issue, it is important to develop novel technologies for the sensitive detection of DENV. The present study reported on the development of plasma-functionalized, graphite-encapsulated magnetic nanoparticles (GrMNPs) conjugated with anti-DENV antibody for DENV capture. Radiofrequency wave-excited inductively-coupled Ar and ammonia gas plasmas were used to introduce amino groups onto the surface of the GrMNPs. The GrMNPs were then conjugated with an antibody against DENV, and the antibody-integrated magnetic beads were assessed for their ability to capture DENV. Beads incubated in a cell culture medium of DENV-infected mosquito cells were separated from the supernatant by applying a magnetic field and were then washed. The adsorption of DENV serotypes 1–4 onto the beads was confirmed using reverse transcription-polymerase chain reaction, which detected the presence of DENV genomic RNA on the GrMNPs. The methodology described in the present study, which employed the plasma-functionalization of GrMNPs to enable antibody-integration, represents a significant improvement in the detection of DENV. PMID:27221214

  12. PROTECTIVE EFFECT OF CUTANEOUS ANTIBODY PRODUCED BY CHANNEL CATFISH IMMUNE TO ICHTHYOPHTHIRIUS ON COHABITED NON-IMMUNE CATFISH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fish recovered from sublethal ichthyophthiriasis acquire protective immunity against Ichthyophthirius (Ich). This study evaluated the protective effect of cutaneous antibody excreted by channel catfish immune to Ich on cohabited non-immune catfish. Non-immune and immune fish controls were separatel...

  13. A Nonfucosylated Variant of the anti-HIV-1 Monoclonal Antibody b12 Has Enhanced FcγRIIIa-Mediated Antiviral Activity In Vitro but Does Not Improve Protection against Mucosal SHIV Challenge in Macaques

    PubMed Central

    Moldt, Brian; Shibata-Koyama, Mami; Rakasz, Eva G.; Schultz, Niccole; Kanda, Yutaka; Dunlop, D. Cameron; Finstad, Samantha L.; Jin, Chenggang; Landucci, Gary; Alpert, Michael D.; Dugast, Anne-Sophie; Parren, Paul W. H. I.; Nimmerjahn, Falk; Evans, David T.; Alter, Galit; Forthal, Donald N.; Schmitz, Jörn E.; Iida, Shigeru; Poignard, Pascal; Watkins, David I.

    2012-01-01

    Eliciting neutralizing antibodies is thought to be a key activity of a vaccine against human immunodeficiency virus (HIV). However, a number of studies have suggested that in addition to neutralization, interaction of IgG with Fc gamma receptors (FcγR) may play an important role in antibody-mediated protection. We have previously obtained evidence that the protective activity of the broadly neutralizing human IgG1 anti-HIV monoclonal antibody (MAb) b12 in macaques is diminished in the absence of FcγR binding capacity. To investigate antibody-dependent cellular cytotoxicity (ADCC) as a contributor to FcγR-associated protection, we developed a nonfucosylated variant of b12 (NFb12). We showed that, compared to fully fucosylated (referred to as wild-type in the text) b12, NFb12 had higher affinity for human and rhesus macaque FcγRIIIa and was more efficient in inhibiting viral replication and more effective in killing HIV-infected cells in an ADCC assay. Despite these more potent in vitro antiviral activities, NFb12 did not enhance protection in vivo against repeated low-dose vaginal challenge in the simian-human immunodeficiency virus (SHIV)/macaque model compared to wild-type b12. No difference in protection, viral load, or infection susceptibility was observed between animals given NFb12 and those given fully fucosylated b12, indicating that FcγR-mediated activities distinct from FcγRIIIa-mediated ADCC may be important in the observed protection against SHIV challenge. PMID:22457527

  14. Development and characterization of a monoclonal antibody against Taura syndrome virus.

    PubMed

    Côté, I; Poulos, B T; Redman, R M; Lightner, D V

    2009-12-01

    We produced a panel of monoclonal antibodies (MAbs) from the fusion of Taura syndrome virus variants from Belize (TSV-BZ) immunized BALB/cJ mouse spleen cells and non-immunoglobulin secreting SP2/0 mouse myeloma cells. One antibody, 2C4, showed strong specificity and sensitivity for TSV in dot-blot immunoassay and immunohistochemistry (IHC) analysis. The MAb reacted against native TSV-BZ, TSV variants from Sinaloa, Mexico (TSV-SI) and TSV variants from Hawaii (TSV-HI) in dot-blot immunoassay. By IHC, the antibody identified the virus in a pattern similar to the digoxigenin-labelled TSV-cDNA probe for the TSV-BZ, TSV-HI and TSV-SI variants, but not for the TSV variants from Venezuela (TSV-VE) and the TSV variants from Thailand (TSV-TH). MAb 2C4 did not react against other shrimp pathogens or with normal shrimp tissue. Western blot analysis showed a strong reaction against CP2, a region of high antigenic variability amongst TSV variants. This antibody has potential diagnostic application in detection and differentiation of certain TSV biotypes. PMID:19602090

  15. EMERGENCE OF SUBGROUP J AVIAN LEUKOSIS VIRUS NEUTRALIZING ANTIBODY ESCAPE VARIANTS IN MEAT-TYPE CHICKENS INFECTED WITH VIRUS AT HATCH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infection of meat-type chickens at hatch with field isolates of Subgroup J avian leukosis virus (ALV J) results in a high incidence of chickens with persistent viremia even in the presence of neutralizing antibodies (NAb) against the inoculated parental virus (V+A+). The purpose of this study was t...

  16. The immune system of cyprinid fish. Kinetics and temperature dependence of antibody-producing cells in carp (Cyprinus carpio).

    PubMed Central

    Rijkers, G T; Frederix-Wolters, E M; van Muiswinkel, W B

    1980-01-01

    After immunization of carp with sheep red blood cells, the spleen accounts for only 5% of the total number of plaque-forming cells (PFC). In addition, thymus, peripheral blood and heart contained low numbers of PFC (< 0.5, 1 and 0.5%, respectively). Pronephros and mesonephros were the major antibody-forming organs (53 and 40% of total PFC, respectively). The temperature dependence of the antibody-forming cell response in spleen, pronephros and mesonephros as studied in animals kept at 12-24 degrees. Lowering temperatures induced a delay in the peak of the primary response but had no effect on the magnitude of the response. The temperature-peak day relationship indicated that there are steps in the primary immune response of carp differing in temperature sensitivity. The anamnestic character of the secondary response was clearly demonstrated at 24 and 20 degrees but lost at 18 degrees. PMID:7000695

  17. Evaluation of a multifunctional staphylokinase variant with thrombin inhibition and antiplatelet aggregation activities produced from salt-inducible E. coli GJ1158.

    PubMed

    Kumar, Anmol; Pulicherla, Krishna Kanth; Mayuren, Candasamy; Kotra, Seetharam; Rao, Krothapalli Rajasurya Sambasiva

    2013-10-01

    Reocclusion is one of the major root causes for secondary complications that arise during thrombolytic therapy. A multifunctional staphylokinase variant SRH (staphylokinase (SAK) linked with tripeptide RGD and didecapeptide Hirulog) with antiplatelet and antithrombin activities in addition to clot specific thrombolytic function, was developed to address the reocclusion problem. We preferred to use Escherichia coli GJ1158 as the host in this study for economic production of SRH by osmotic (0.3 mol/L sodium chloride) induction, to overcome the problems associated with the yeast expression system. The therapeutic potential of SRH was evaluated in the murine model of vascular thrombosis. The SAK protein (1 mg/kg body mass) and SRH protein (1 mg/kg and 2 mg/kg) were administered intravenously to the different treatment groups. The results have shown a dose-dependent antithrombotic effect in carrageenan-induced mouse tail thrombosis. The thrombin time, activated partial thromboplastin time, and prothrombin time were significantly prolonged (p < 0.05) in the SRH-infused groups. Moreover, SRH inhibited platelet aggregation in a dose-dependent manner (p < 0.05), while the bleeding time was significantly (p < 0.05) prolonged. All of these results inferred that the osmotically produced multifunctional fusion protein SRH (SAK-RGD-Hirulog) is a promising thrombolytic agent, and one which sustained its multifunctionality in the animal models. PMID:24144055

  18. High-level carbapenem-resistant OXA-48-producing Klebsiella pneumoniae with a novel OmpK36 variant and low-level, carbapenem-resistant, non-porin-deficient, OXA-181-producing Escherichia coli from Thailand.

    PubMed

    Lunha, Kamonwan; Chanawong, Aroonwadee; Lulitanond, Aroonlug; Wilailuckana, Chotechana; Charoensri, Nicha; Wonglakorn, Lumyai; Saenjamla, Pimjai; Chaimanee, Prajuab; Angkititrakul, Sunpetch; Chetchotisakd, Ploenchan

    2016-06-01

    Five blaOXA-48-like-carrying Enterobacteriaceae isolates collected from two Thai patients in December 2012 were characterized. Three Klebsiella pneumoniae isolates giving two different pulsed-field gel electrophoresis patterns and sequence types (ST11 and ST37) from patient 1 harbored blaOXA-48 locating on Tn1999.2, whereas two Escherichia coli isolates with the same pulsotype and ST5 from Patient 2 carried ISEcp1-associated blaOXA-181. One K. pneumoniae strain had blaSHV-12, blaDHA-1, qnrB, and qnrS, while another strain harbored blaCTX-M-15, qnrS and aac(6')-Ib-cr. The E. coli strain contained blaCTX-M-15, blaCMY-2, qnrS, and aac(6')-Ib-cr. Interestingly, the OXA-48 producers with a novel OmpK36 variant by a substitution of Gly to Asp in the L3 loop-borne PEFXG motif exhibited high-level resistance to ertapenem, imipenem, and meropenem. In contrast, the OXA-181 producer with non-porin-deficient background showed low-level resistance to ertapenem only. Both patients died because of either septic shock or pneumonia. This study showed the impact of OXA-48-like carbapenemases in porin-defective clinical isolate background, which may lead to serious therapeutic problems in the near future. PMID:27041106

  19. Blocking of Histamine Release and IgE Binding to FcεRI on Human Basophils by Antibodies Produced in Camels

    PubMed Central

    Sana, Yousef; Abdulrahman, Rawashdeh; Raida, Khalil; Sami, Abdel-Hafez

    2015-01-01

    Purpose The production of camel heavy-chain antihuman IgE (huIgE) that has the potential to block IgE-FcεRI interaction and histamine release by basophils. Methods Camels were immunized with a synthetic loop peptide (SLP) designed in a multiple antigen peptide system (MAPS) forming SLP-MAPS immunogen. Camel polyclonal antibodies (PCAs) were produced, purified, characterized using Protein A & G, ELISA, and SDS-PAGE, and tested for their potency to block passive sensitization and histamine release of human basophils using flow cytometry (FCM) and ELISA, respectively. Results FCM data indicated that camel conventional (IgG1) and heavy chain antibodies (HCAbs; IgG2, and IgG3) had blocking activities of 43.9%, 72%, and 96.6%, respectively. Moreover, both IgG2 and IgG3 achieved remarkable inhibition rates of 93.98% and 97.05% in histamine release, respectively, whereas the IgG1inhibiting activity was 60.05%. Conclusions Camel PCAs produced against SLP-MAPS were capable of blocking the IgE-receptor interaction and the release of histamine by basophils with superiority to HCAbs. These findings may pave the way toward the possible use of camel anti-huIgE HCAbs as blocking antibodies in the treatment of IgE-mediated allergy and asthma. PMID:26333705

  20. A Phase I Study of a Combination of Yttrium-90 labeled Anti-CEA Antibody and Gemcitabine in Patients with CEA Producing Advanced Malignancies

    PubMed Central

    Shibata, Stephen; Raubitschek, Andrew; Leong, Lucille; Koczywas, Marianna; Williams, Lawrence; Zhan, Jiping; Wong, Jeffrey Y.C.

    2011-01-01

    Purpose To determine the maximum tolerated dose of combined therapy using an yttrium-90 labeled anti-CEA antibody with gemcitabine in patients with advanced CEA producing solid tumors. Experimental Design The chimeric human/murine cT84.66 is an anti-CEA intact IgG1, with high affinity and specificity to CEA. This was given at a fixed yttrium-90 labeled dose of 16.6 mCi/m2 to subjects who had and an elevated CEA in serum or in tumor by immunohistochemistry. Also required was a tumor that imaged with an 111In labeled cT84.66 antibody. Patients were treated with escalating doses of gemcitabine given intravenously over 30 minutes on day 1 and 3 after the infusion of the yttrium-90 labeled antibody. Patients were treated in cohorts of 3. The maximum tolerated dose was determined as the highest level at which no more than 1 of 6 patients experienced a dose limiting toxicity. Results A total of 36 patients were enrolled, and all but one had prior systemic therapy. The maximum tolerated dose of gemcitabine in this combination was 150mg/m2. Dose limiting toxicities at a gemcitabine dose of 165mg/m2 included a grade 3 rash and grade 4 neutropenia. One partial response was seen in a patient with colorectal cancer, and 4 patients had a > 50% decrease in baseline CEA levels associated with stable disease. Human antichimeric antibody responses were the primary reason for stopping treatment in 12 patients. Conclusions feasibility of combining gemcitabine with an yttrium-90 labeled anti-CEA antibody is demonstrated with preliminary evidence of clinical response. PMID:19351765

  1. Large-Scale Purification of r28M: A Bispecific scFv Antibody Targeting Human Melanoma Produced in Transgenic Cattle

    PubMed Central

    Spiesberger, Katrin; Paulfranz, Florian; Egger, Anton; Reiser, Judith; Vogl, Claus; Rudolf-Scholik, Judith; Mayrhofer, Corina; Grosse-Hovest, Ludger; Brem, Gottfried

    2015-01-01

    Background 30 years ago, the potential of bispecific antibodies to engage cytotoxic T cells for the lysis of cancer cells was discovered. Today a variety of bispecific antibodies against diverse cell surface structures have been developed, the majority of them produced in mammalian cell culture systems. Beside the r28M, described here, no such bispecific antibody is known to be expressed by transgenic livestock, although various biologicals for medical needs are already harvested—mostly from the milk—of these transgenics. In this study we investigated the large-scale purification and biological activity of the bispecific antibody r28M, expressed in the blood of transgenic cattle. This tandem single-chain variable fragment antibody is designed to target human CD28 and the melanoma/glioblastoma-associated cell surface chondroitin sulfate proteoglycan 4 (CSPG4). Results With the described optimized purification protocol an average yield of 30 mg enriched r28M fraction out of 2 liters bovine plasma could be obtained. Separation of this enriched fraction by size exclusion chromatography into monomers, dimers and aggregates and further testing regarding the biological activity revealed the monomer fraction as being the most appropriate one to continue working with. The detailed characterization of the antibody’s activity confirmed its high specificity to induce the killing of CSPG4 positive cells. In addition, first insights into tumor cell death pathways mediated by r28M-activated peripheral blood mononuclear cells were gained. In consideration of possible applications in vivo we also tested the effect of the addition of different excipients to r28M. Conclusion Summing up, we managed to purify monomeric r28M from bovine plasma in a large-scale preparation and could prove that its biological activity is unaffected and still highly specific and thus, might be applicable for the treatment of melanoma. PMID:26469402

  2. Optimisation of the purification process of a tumour-targeting antibody produced in N. benthamiana using vacuum-agroinfiltration.

    PubMed

    Lombardi, Raffaele; Villani, Maria Elena; Di Carli, Mariasole; Brunetti, Patrizia; Benvenuto, Eugenio; Donini, Marcello

    2010-12-01

    It was previously demonstrated that the tumour-targeting antibody mAb H10 can be transiently expressed and purified at high levels in Nicotiana benthamiana by using a vacuum-agroinfiltration system boosted by the use of a virus silencing suppressor protein. Scope of this work was to analyse different steps of protein extraction from agroinfiltrated leaves to optimise the purification process of the secretory mAb H10 providing new insights in the field of large-scale plant production. Two different extraction procedures (mechanical shearing/homogenisation and recovery of intercellular fluids -IFs-) were evaluated and compared in terms of purified antibody yields, antibody degradation and total phenolic compounds content. Mechanical grinding from fresh leaf tissues gave the highest purification yield (75 mg/kg Fresh Weight -75% intact tetrameric IgG-) and total phenolics concentration in the range of 420 μg/g FW. The second extraction procedure, based on the recovery of IFs, gave purification yields of 15-20 mg/kg FW (corresponding to 27% of total soluble protein) in which about 40% of purified protein is constituted by fully assembled IgG with a total phenolic compounds content reduced by one order of magnitude (21 μg/g FW). Despite a higher antibody degradation, purification from intercellular fluids demonstrated to be very promising since extraction procedures resulted extremely fast and amenable to scaling-up. Overall data highlight that different extraction procedures can dramatically affect the proteolytic degradation and quality of antibody purified from agroinfiltrated N. benthamiana leaves. Based on these results, we optimised a pilot-scale purification protocol using a two-step purification procedure from batches of fresh agroinfiltrated leaves (250 g) allowing purification of milligram quantities (average yield 40 mg/kg FW) of fully assembled and functional IgG with a 99.4% purity, free of phenolic and alkaloid compounds with low endotoxin levels

  3. Antibody-induced oligomerization and activation of an engineered reporter enzyme

    PubMed Central

    Geddie, Melissa L.; Matsumura, Ichiro

    2007-01-01

    Summary Our objective is to produce a protein biosensor (or molecular switch) that is specifically activated in solution by a monoclonal antibody. Many effector-dependent enzymes have evolved in nature, but the introduction of a novel regulatory mechanism into a normally unregulated enzyme poses a difficult design problem. We used site-saturation mutagenesis and screening to generate antibody-activated variants of the reporter enzyme beta-glucuronidase (GUS). The specific activity of the purified epitope-tagged GUS variant was increased by up to ~500-fold by the addition an equimolar concentration of a monoclonal antibody. This molecular switch is modular in design, so it can easily be re-engineered for the detection of other peptide-specific antibodies. Such antibody-activated reporters could someday enable point-of-care serological assays for the rapid detection of infectious diseases. PMID:17467736

  4. Characterization of anti-P monoclonal antibodies directed against the ribosomal protein–RNA complex antigen and produced using Murphy Roths large autoimmune-prone mice

    PubMed Central

    Sato, H; Onozuka, M; Hagiya, A; Hoshino, S; Narita, I; Uchiumi, T

    2015-01-01

    Autoantibodies, including anti-ribosomal P proteins (anti-P), are thought to be produced by an antigen-driven immune response in systemic lupus erythematosus (SLE). To test this hypothesis, we reconstituted the ribosomal antigenic complex in vitro using human P0, phosphorylated P1 and P2 and a 28S rRNA fragment covering the P0 binding site, and immunized Murphy Roths large (MRL)/lrp lupus mice with this complex without any added adjuvant to generate anti-P antibodies. Using hybridoma technology, we subsequently obtained 34 clones, each producing an anti-P monoclonal antibody (mAb) that recognized the conserved C-terminal tail sequence common to all three P proteins. We also obtained two P0-specific monoclonal antibodies, but no antibody specific to P1, P2 or rRNA fragment. Two types of mAbs were found among these anti-P antibodies: one type (e.g. 9D5) reacted more strongly with the phosphorylated P1 and P2 than that with their non-phosphorylated forms, whereas the other type (e.g. 4H11) reacted equally with both phosphorylated and non-phosphorylated forms of P1/P2. Both 9D5 and 4H11 inhibited the ribosome/eukaryotic elongation factor-2 (eEF-2)-coupled guanosine triphosphate (GTP)ase activity. However, preincubation with a synthetic peptide corresponding to the C-terminal sequence common to all three P proteins, but not the peptide that lacked the last three C-terminal amino acids, mostly prevented the mAb-induced inhibition of GTPase activity. Thus, at least two types of anti-P were produced preferentially following the immunization of MRL mice with the reconstituted antigenic complex. Presence of multiple copies of the C-termini, particularly that of the last three C-terminal amino acid residues, in the antigenic complex appears to contribute to the immunogenic stimulus. PMID:25255895

  5. Maternal autism-associated IgG antibodies delay development and produce anxiety in a mouse gestational transfer model

    PubMed Central

    Braunschweig, Daniel; Golub, Mari S.; Koenig, Claire M.; Qi, Lihong; Pessah, Isaac N.; Van de Water, Judy; Berman, Robert F.

    2014-01-01

    A murine passive transfer model system was employed to ascertain the effects of gestational exposure to a single, intravenous dose of purified, brain-reactive IgG antibodies from individual mothers of children with autism (MAU) or mothers with typically developing children (MTD). Growth and behavioral outcomes in offspring were measured from postnatal days 8 – 65 in each group. Comparisons revealed alterations in early growth trajectories, significantly impaired motor and sensory development, and increased anxiety. This report demonstrates for the first time the effects of a single, low dose gestational exposure of IgG derived from individual MAU on their offspring’s physical and social development. PMID:22951357

  6. mcr-1.2, a New mcr Variant Carried on a Transferable Plasmid from a Colistin-Resistant KPC Carbapenemase-Producing Klebsiella pneumoniae Strain of Sequence Type 512.

    PubMed

    Di Pilato, Vincenzo; Arena, Fabio; Tascini, Carlo; Cannatelli, Antonio; Henrici De Angelis, Lucia; Fortunato, Simona; Giani, Tommaso; Menichetti, Francesco; Rossolini, Gian Maria

    2016-09-01

    A novel mcr variant, named mcr-1.2, encoding a Gln3-to-Leu functional variant of MCR-1, was detected in a KPC-3-producing ST512 Klebsiella pneumoniae isolate collected in Italy from a surveillance rectal swab from a leukemic child. The mcr-1.2 gene was carried on a transferable IncX4 plasmid whose structure was very similar to that of mcr-1-bearing plasmids previously found in Escherichia coli and K. pneumoniae strains from geographically distant sites (Estonia, China, and South Africa). PMID:27401575

  7. Capture of dengue viruses using antibody-integrated graphite-encapsulated magnetic beads produced using gas plasma technology.

    PubMed

    Sakudo, Akikazu; Viswan, Anchu; Chou, Han; Sasaki, Tadahiro; Ikuta, Kazuyoshi; Nagatsu, Masaaki

    2016-07-01

    Despite significant advances in medicine, global health is threatened by emerging infectious diseases caused by a number of viruses. Dengue virus (DENV) is a mosquito‑borne virus, which can be transmitted to humans via mosquito vectors. Previously, the Ministry of Health, Labour and Welfare in Japan reported the country's first domestically acquired case of dengue fever for almost 70 years. To address this issue, it is important to develop novel technologies for the sensitive detection of DENV. The present study reported on the development of plasma-functionalized, graphite-encapsulated magnetic nanoparticles (GrMNPs) conjugated with anti-DENV antibody for DENV capture. Radiofrequency wave‑excited inductively‑coupled Ar and ammonia gas plasmas were used to introduce amino groups onto the surface of the GrMNPs. The GrMNPs were then conjugated with an antibody against DENV, and the antibody‑integrated magnetic beads were assessed for their ability to capture DENV. Beads incubated in a cell culture medium of DENV‑infected mosquito cells were separated from the supernatant by applying a magnetic field and were then washed. The adsorption of DENV serotypes 1‑4 onto the beads was confirmed using reverse transcription‑polymerase chain reaction, which detected the presence of DENV genomic RNA on the GrMNPs. The methodology described in the present study, which employed the plasma-functionalization of GrMNPs to enable antibody‑integration, represents a significant improvement in the detection of DENV. PMID:27221214

  8. Specific N-linked and O-linked glycosylation modifications in the envelope V1 domain of simian immunodeficiency virus variants that evolve in the host alter recognition by neutralizing antibodies.

    PubMed Central

    Chackerian, B; Rudensey, L M; Overbaugh, J

    1997-01-01

    During progression to AIDS in simian immunodeficiency virus (SIV) Mne-infected macaques, viral variants are selected that encode sequences with serine and threonine changes in variable region 1 (V1) of the surface component of the viral envelope protein (Env-SU). Because these serine and threonine amino acid changes are characteristic of sites for O-linked and N-linked glycosylation, we examined whether they were targets for modification by carbohydrates. For this purpose, we used several biochemical methods for analyzing the Env-SU protein encoded by chimeras of SIVMneCL8 and envelope sequences cloned from an SIVMneCL8-infected Macaca nemestrina during clinical latency and just after the onset of AIDS. The addition of an N-linked glycan was demonstrated by changes in the electrophoretic mobility of Env-SU, and this was verified by specific glycanase digestions and a detailed analysis of the molecular mass of partially purified Env-SU by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Molecular mass calculations by MALDI-TOF MS also demonstrated an increased mass, from 102.3 to 103.5 kDa, associated with serine and threonine residues predicted to be O-linked glycosylation sites. Together, these data provide the first direct evidence that the carbohydrate profile of Env-SU is distinct in SIV variants that evolve during infection of the host. Moreover, our studies show that these changes in glycosylation in V1 were directly associated with changes in antigenicity. Specifically, serine and threonine changes in V1 allowed the virus to escape neutralization by macaque sera that contained antibodies that could neutralize the parental virus, SIVMneCL8. The escape from antibody recognition appeared to be influenced by either O-linked or N-linked carbohydrate additions in V1. Moreover, when glycine residues were engineered at the positions where serine and threonine changes evolve in V1 of SIVMneCL8, there was no change in

  9. Crystal Structure of Serine Racemase that Produces Neurotransmitter variant:small-caps">d-Serine for Stimulation of the NMDA Receptor

    NASA Astrophysics Data System (ADS)

    Goto, Masaru

    variant:small-caps">d-Serine is an endogenous coagonist for the N-methyl-variant:small-caps">d-aspartate receptor and is involved in excitatory neurotransmission in the brain. Mammalian pyridoxal 5’-phosphate-dependent serine racemase, which is localized in the mammalian brain, catalyzes the racemization of variant:small-caps">l-serine to yield variant:small-caps">d-serine and vice versa. We have determined the structures of three forms of the mammalian enzyme homolog from Schizosaccharomyces pombe. Lys57 and Ser82 located on the protein and solvent sides, respectively, with respect to the cofactor plane, are acid-base catalysts that shuttle protons to the substrate. The modified enzyme, which has a unique lysino-variant:small-caps">d-alanyl residue at the active site, also binds the substrate serine in the active site, suggesting that the lysino-variant:small-caps">d-alanyl residue acts as a catalytic base in the same manner as Lys57 of the wild type enzyme.

  10. Differential analyses of major allergen proteins in wild-type rice and rice producing a fragment of anti-rotavirus antibody.

    PubMed

    Yuki, Yoshikazu; Kurokawa, Shiho; Kozuka-Hata, Hiroko; Tokuhara, Daisuke; Mejima, Mio; Kuroda, Masaharu; Oyama, Masaaki; Nishimaki-Mogami, Tomoko; Teshima, Reiko; Kiyono, Hiroshi

    2016-04-01

    To develop oral antibody therapy against rotavirus infection, we previously produced a recombinant fragment of llama heavy-chain antibody to rotavirus (ARP1) in rice seeds (MucoRice-ARP1). We intend to use a purification-free rice powder for clinical application but needed to check whether MucoRice-ARP1 had increased levels of known allergen proteins. For this purpose, we used two-dimensional fluorescence difference gel electrophoresis to compare the allergen protein levels in MucoRice-ARP1 and wild-type rice. We detected no notable differences, except in the levels of α-amylase/trypsin inhibitor-like family proteins. Because by this approach we could not completely separate ARP1 from the proteins of this family, we confirmed the absence of changes in the levels of these allergens by using shotgun mass spectrometry as well as immunoblot. By using immunoelectron microscopy, we also showed that RAG2, a member of the α-amylase/trypsin inhibitor-like protein family, was relocated from protein bodies II to the plasma membrane or cell wall in MucoRice-ARP1 seed. The relocation did not affect the level of RAG2. We demonstrated that most of the known rice allergens were not considerably upregulated by the genetic modification in MucoRice-ARP1. Our data suggest that MucoRice-ARP1 is a potentially safe oral antibody for clinical application. PMID:26851506

  11. Antibody Titer Has Positive Predictive Value for Vaccine Protection against Challenge with Natural Antigenic-Drift Variants of H5N1 High-Pathogenicity Avian Influenza Viruses from Indonesia

    PubMed Central

    Suarez, David L.; Spackman, Erica; Jadhao, Samadhan; Dauphin, Gwenaelle; Kim-Torchetti, Mia; McGrane, James; Weaver, John; Daniels, Peter; Wong, Frank; Selleck, Paul; Wiyono, Agus; Indriani, Risa; Yupiana, Yuni; Sawitri Siregar, Elly; Prajitno, Teguh; Smith, Derek; Fouchier, Ron

    2015-01-01

    antigenic variant wild-type viruses or rg-generated LPAI virus seed strains containing the hemagglutinin and neuraminidase genes of wild-type viruses. IMPORTANCE H5N1 high-pathogenicity avian influenza (HPAI) virus has become endemic in Indonesian poultry, and such poultry are the source of virus for birds and mammals, including humans. Vaccination has become a part of the poultry control strategy, but vaccine failures have occurred in the field. This study identified possible causes of vaccine failure, which included the use of an unlicensed virus seed strain and induction of low levels of protective antibody because of an insufficient quantity of vaccine antigen. However, the most important cause of vaccine failure was the appearance of drift variant field viruses that partially or completely overcame commercial vaccine-induced immunity. Furthermore, experimental vaccines using inactivated wild-type virus or reverse genetics-generated vaccines containing the hemagglutinin and neuraminidase genes of wild-type drift variant field viruses were protective. These studies indicate the need for surveillance to identify drift variant viruses in the field and update licensed vaccines when such variants appear. PMID:25609805

  12. Persistence survey of Toxic Shock Syndrome toxin-1 producing Staphylococcus aureus and serum antibodies to this superantigen in five groups of menstruating women

    PubMed Central

    2010-01-01

    Background Menstrual Toxic Shock Syndrome (mTSS) is thought to be associated with the vaginal colonization with specific strains of Staphylococcus aureus TSST-1 in women who lack sufficient antibody titers to this toxin. There are no published studies that examine the seroconversion in women with various colonization patterns of this organism. Thus, the aim of this study was to evaluate the persistence of Staphylococcus aureus colonization at three body sites (vagina, nares, and anus) and serum antibody to toxic shock syndrome toxin-producing Staphylococcus aureus among a small group of healthy, menstruating women evaluated previously in a larger study. Methods One year after the completion of that study, 311 subjects were recalled into 5 groups. Four samples were obtained from each participant at several visits over an additional 6-11 month period: 1) an anterior nares swab; 2) an anal swab; 3) a vagina swab; and 4) a blood sample. Gram stain, a catalase test, and a rapid S. aureus-specific latex agglutination test were performed to phenotypically identify S. aureus from sample swabs. A competitive ELISA was used to quantify TSST-1 production. Human TSST-1 IgG antibodies were determined from the blood samples using a sandwich ELISA method. Results We found only 41% of toxigenic S. aureus and 35.5% of non-toxigenic nasal carriage could be classified as persistent. None of the toxigenic S. aureus vaginal or anal carriage could be classified as persistent. Despite the low persistence of S. aureus colonization, subjects colonized with a toxigenic strain were found to display distributions of antibody titers skewed toward higher titers than other subjects. Seven percent (5/75) of subjects became seropositive during recall, but none experienced toxic shock syndrome-like symptoms. Conclusions Nasal carriage of S. aureus appears to be persistent and the best predicator of subsequent colonization, whereas vaginal and anal carriage appear to be more transient. From these

  13. Human Polyclonal Antibodies Produced through DNA Vaccination of Transchromosomal Cattle Provide Mice with Post-Exposure Protection against Lethal Zaire and Sudan Ebolaviruses

    PubMed Central

    Bounds, Callie E.; Kwilas, Steven A.; Kuehne, Ana I.; Brannan, Jennifer M.; Bakken, Russell R.; Dye, John M.; Hooper, Jay W.; Dupuy, Lesley C.; Ellefsen, Barry; Hannaman, Drew; Wu, Hua; Jiao, Jin-an; Sullivan, Eddie J.; Schmaljohn, Connie S.

    2015-01-01

    DNA vaccination of transchromosomal bovines (TcBs) with DNA vaccines expressing the codon-optimized (co) glycoprotein (GP) genes of Ebola virus (EBOV) and Sudan virus (SUDV) produce fully human polyclonal antibodies (pAbs) that recognize both viruses and demonstrate robust neutralizing activity. Each TcB was vaccinated by intramuscular electroporation (IM-EP) a total of four times and at each administration received 10 mg of the EBOV-GPco DNA vaccine and 10 mg of the SUDV-GPco DNA vaccine at two sites on the left and right sides, respectively. After two vaccinations, robust antibody responses (titers > 1000) were detected by ELISA against whole irradiated EBOV or SUDV and recombinant EBOV-GP or SUDV-GP (rGP) antigens, with higher titers observed for the rGP antigens. Strong, virus neutralizing antibody responses (titers >1000) were detected after three vaccinations when measured by vesicular stomatitis virus-based pseudovirion neutralization assay (PsVNA). Maximal neutralizing antibody responses were identified by traditional plaque reduction neutralization tests (PRNT) after four vaccinations. Neutralizing activity of human immunoglobulins (IgG) purified from TcB plasma collected after three vaccinations and injected intraperitoneally (IP) into mice at a 100 mg/kg dose was detected in the serum by PsVNA up to 14 days after administration. Passive transfer by IP injection of the purified IgG (100 mg/kg) to groups of BALB/c mice one day after IP challenge with mouse adapted (ma) EBOV resulted in 80% protection while all mice treated with non-specific pAbs succumbed. Similarly, interferon receptor 1 knockout (IFNAR -/-) mice receiving the purified IgG (100 mg/kg) by IP injection one day after IP challenge with wild type SUDV resulted in 89% survival. These results are the first to demonstrate that filovirus GP DNA vaccines administered to TcBs by IM-EP can elicit neutralizing antibodies that provide post-exposure protection. Additionally, these data describe

  14. Species specificity of a monoclonal antibody produced to Naegleria fowleri and partial characterization of its antigenic determinant.

    PubMed

    Réveiller, F L; Marciano-Cabral, F; Pernin, P; Cabanes, P A; Legastelois, S

    2000-08-01

    Monoclonal antibody (Mab) 5D12 against Naegleria fowleri was analyzed for species specificity. Mab 5D12 reacted with a ubiquitous epitope present on the membrane of N. fowleri but not with soluble antigens. The Mab did not react with N. lovaniensis, N. gruberi, N. australiensis, or Acanthamoeba castellanii. The decreased reactivity of Mab 5D12 with N. fowleri observed after periodate oxidation, after digestion of carbohydrate moieties by three glycosidases, or after treatment of amebas with tunicamycin strongly suggests that the antigenic determinant has a polysaccharide component. Inhibition of the reactivity of Mab 5D12 by soluble saccharides supports the idea that N-acetyl or amino groups may play an important role in the recognition of the carbohydrate component of the epitope by the Mab. The specificity of Mab 5D12 makes this an ideal reagent for the identification of N. fowleri in environmental samples or in clinical specimens. PMID:10952262

  15. Versuche zur Gewinnung von katalytischen Antikörpern zur Hydrolyse von Arylcarbamaten und Arylharnstoffen. (English Title: Attempts to produce catalytic antibodies for hydrolysis of arylcarbamates and arylureas)

    NASA Astrophysics Data System (ADS)

    Werner, Deljana

    2002-05-01

    Umsatzgeschwindigkeit eine lineare Abhängigkeit festgestellt. Die thermodynamische Gleichtgewichtsdissoziationskonstante KD des Abzyms von 2,6 nM zeugt von einer sehr guten Affinität zum ÜZA. Hydrolytisch aktiv waren nur Antikörper, die gegen das Übergangszustandsanalogon Hei3 hergestellt worden waren. Es wird vermutet, dass die Hydrolyse der Benzylphenylcarbamate über einen Additions-Eliminierungsmechanismus unter Ausbildung eines tetraedrischen Übergangszustandes verläuft, dessen analoge Verbindung Hei3 ist. Im Rahmen der Generierung von Nachweisantikörpern zur Detektion der Substratabnahme bei der Hydrolyse wurden Anti-Diuron-Antikörper hergestellt. Einer der Antikörper (B91-CG5) ist spezifisch für das Herbizid Diuron und hat einen IC50-Wert von 0,19 µg/l und eine untere Nachweisgrenze von 0,04 µg/l. Ein anderer Antikörper (B91-KF5) reagiert kreuz mit einer Palette ähnlicher Herbizide. Mit diesen Antikörpern wurde ein empfindlicher Labortest, der ein Monitoring von Diuron auf Grundlage des durch die Trinkwasserverordnung festgeschriebenen Wertes für Pflanzenschutzmittel von 0,1 µg/l erlaubt, aufgebaut. Der Effekt der Anti-Diuron-Antikörper auf die Diuron-inhibierte Photosynthese wurde in vitro und in vivo untersucht. Es wurde nachgewiesen, dass sowohl in isolierten Thylakoiden, als auch in intakten Algen eine Vorinkubation der Anti-Diuron-Antikörper mit Diuron zur Inaktivierung seiner Photosynthese-hemmenden Wirkung führt. Wurde der Elektronentransport in den isolierten Thylakoiden oder in Algen durch Diuron unterbrochen, so führte die Zugabe der Anti-Diuron-Antikörper zur Reaktivierung der Elektronenübertragung. Attempts to produce catalytic antibodies for hydrolysis of arylcarbamates and arylureas: The aim of the investigations was to produce antibodies which are able to cleave herbicides resistant to naturally occuring enzymes. Structurally similar carbamate and urea derivatives were chosen for the experiments. Phosphonate derivatives were synthesized

  16. Cellulase variants

    SciTech Connect

    Blazej, Robert; Toriello, Nicholas; Emrich, Charles; Cohen, Richard N.; Koppel, Nitzan

    2015-07-14

    This invention provides novel variant cellulolytic enzymes having improved activity and/or stability. In certain embodiments the variant cellulotyic enzymes comprise a glycoside hydrolase with or comprising a substitution at one or more positions corresponding to one or more of residues F64, A226, and/or E246 in Thermobifida fusca Cel9A enzyme. In certain embodiments the glycoside hydrolase is a variant of a family 9 glycoside hydrolase. In certain embodiments the glycoside hydrolase is a variant of a theme B family 9 glycoside hydrolase.

  17. One Injection of DsRed Followed by Bites from Transgenic Mosquitoes Producing DsRed in the Saliva Elicits a High Titer of Antibody in Mice

    PubMed Central

    Matsuoka, Hiroyuki; Sano, Gen-ichiro; Hattori, Ryuta; Tomita, Hiroyuki; Yamamoto, Daisuke S.; Hirai, Makoto

    2012-01-01

    It has been proposed that transgenic mosquitoes can be used as a “flying syringe” for infectious disease control. We succeeded in generating a transgenic (TG) mosquito, Anopheles stephensi, excreting and discharging DsRed in saliva. DsRed was deposited on the membrane where the TG mosquito probed with its proboscis. Repeated feeding by the TG mosquitoes induced anti-DeRed as well as anti-SG antibodies in mice. This indicates that the TG mosquitoes can immunize the animal. Moreover, in this report, we employed a pre-immunization method before exposing mice to the TG mosquitoes. We injected DsRed to mice to prepare memory B cells and exposed the mice to bites by the TG mosquitoes excreting DsRed. The mice produced a higher titer of antibody to DsRed, suggesting that the bites from TG mosquitoes act as a booster and that primary immunization with a vaccine protein and exposure to TG mosquitoes excreting the vaccine protein in the saliva produces a synergistic effect. PMID:23097619

  18. An in vitro combined antibiotic/antibody treatment eliminates toxicity from Shiga toxin-producing E. coli

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Treating Shiga toxin-producing Escherichia coli (STEC) gastrointestinal infections is a difficult endeavor. The utility of antibiotics as an STEC treatment is controversial since antibiotic resistance among STEC isolates is widespread and certain antibiotics dramatically increase express...

  19. A novel β-globin gene mutation HBB.c.22 G>C produces a hemoglobin variant (Hb Vellore) mimicking HbS in HPLC.

    PubMed

    Edison, E S; Sathya, M; Rajkumar, S V; Nair, S C; Srivastava, A; Shaji, R V

    2012-10-01

    Hemoglobinopathies are highly prevalent in Indian population. DNA analysis to detect causative mutations is required for identifying rare hemoglobin variants or when hematological results are discordant with the clinical phenotype. In this report, we describe a novel hemoglobin variant caused by a mutation in beta-globin gene, Codon 7 GAG→CAG (Glu→Gln) that elutes in the position of sickle haemoglobin (HbS) in cation exchange high performance liquid chromatography. This report highlights possible diagnostic pitfalls in interpreting data solely based on haemoglobin analysis and usefulness of mutation screening in definitive diagnosis of hemoglobinopathies. PMID:22471768

  20. Application of a risk analysis method to different technologies for producing a monoclonal antibody employed in hepatitis B vaccine manufacturing.

    PubMed

    Milá, Lorely; Valdés, Rodolfo; Tamayo, Andrés; Padilla, Sigifredo; Ferro, Williams

    2012-03-01

    CB.Hep-1 monoclonal antibody (mAb) is used for a recombinant Hepatitis B vaccine manufacturing, which is included in a worldwide vaccination program against Hepatitis B disease. The use of this mAb as immunoligand has been addressed into one of the most efficient steps of active pharmaceutical ingredient purification process. Regarding this, Quality Risk Management (QRM) provides an excellent framework for the risk management use in pharmaceutical manufacturing and quality decision-making applications. Consequently, this study sought applying a prospective risk analysis methodology Failure Mode Effects Analysis (FMEA) as QRM tool for analyzing different CB.Hep-1 mAb manufacturing technologies. As main conclusions FMEA was successfully used to assess risks associated with potential problems in CB.Hep-1 mAb manufacturing processes. The severity and occurrence of risks analysis evidenced that the percentage of very high severe risks ranged 31.0-38.7% of all risks and the huge majority of risks have a very low occurrence level (61.9-83.3%) in all assessed technologies. Finally, additive Risk Priority Number, was descending ordered as follow: transgenic plants (2636), ascites (2577), transgenic animals (2046) and hollow fiber bioreactors (1654), which also corroborated that in vitro technology, should be the technology of choice for CB.Hep-1 mAb manufacturing in terms of risks and mAb molecule quality. PMID:22285820

  1. Double-peak elution profile of a monoclonal antibody in cation exchange chromatography is caused by histidine-protonation-based charge variants.

    PubMed

    Luo, Haibin; Cao, Mingyan; Newell, Kelcy; Afdahl, Christopher; Wang, Jihong; Wang, William K; Li, Yuling

    2015-12-11

    We have systemically investigated unusual elution behaviors of an IgG4 (mAb A) in cation exchange chromatography (CEX). This mAb A exhibited two elution peaks under certain conditions when being purified by several strong CEX columns. When either of the two peaks was isolated and re-injected on the same column, the similar pattern was observed again during elution. The protein distribution between the two peaks could be altered by NaCl concentration in the feed, or NaCl concentration in wash buffer, or elution pH, suggesting two pH-associated strong-and-weak binding configurations. The protein distributions under different pH values showed good correlation with protonated/un-protonated fractions of a histidine residue. These results suggest that the double-peak elution profile associates with histidine-protonation-based charge variants. By conducting pepsin digestion, amino-acid specific chemical modifications, peptide mapping, and measuring the effects of elution residence time, a histidine in the variable fragment (Fab) was identified to be the root cause. Besides double-peak pattern, mAb A can also exhibit peak-shouldering or single elution peak on different CEX resins, reflecting different resins' resolving capability on protonated/un-protonated forms. This work characterizes a novel cause for unusual elution behaviors in CEX and also provides alternative avenues of purification development for mAbs with similar behaviors. PMID:26596869

  2. Novel Antibody Vectors for Imaging

    PubMed Central

    Olafsen, Tove; Wu, Anna M.

    2010-01-01

    Non-invasive molecular imaging approaches include nuclear, optical, MRI, CT, ultrasound and photoacoustic imaging, which require accumulation of a signal delivered by a probe at the target site. Monoclonal antibodies (mAbs) are high affinity molecules that can be used for specific, high signal delivery to cell surface molecules. However, their long circulation time in blood makes them unsuitable as imaging probes. Efforts to improve antibodies pharmacokinetics without compromising affinity and specificity have been made through protein engineering. Antibody variants that differ in antigen binding sites and size have been generated and evaluated as imaging probes to target tissues of interest. Fast clearing fragments such as single-chain Fv (scFv; 25 kDa) with one antigen binding site (monovalent) demonstrated low accumulation in tumors due the low exposure time to the target. Using scFv as building block to produce larger, bivalent fragments such as scFv dimers (diabodies, 50 kDa) and scFv-fusion proteins (80 kDa minibodies and 105 kDa scFv-Fc) resulted in higher tumor accumulation due to their longer residence time in blood. Imaging studies with these fragments following radiolabeling have demonstrated excellent, high contrast images in gamma cameras and PET scanners. Several studies have also investigated antibody fragments conjugated to fluorescence (near infrared dyes), bioluminescence (luciferases) and quantum dots for optical imaging and iron oxides nanoparticles for MRI. However, these studies indicate that there are several factors that influence successful targeting and imaging. These include stability of the antibody fragment, the labeling chemistry (direct or indirect), whether critical residues are modified, the number of antigen expressed on the cell, and whether the target has a rapid recycling rate or internalizes upon binding. The preclinical data presented are compelling and it is evident that antibody-based molecular imaging tracers will play an

  3. A direct qPCR method for residual DNA quantification in monoclonal antibody drugs produced in CHO cells.

    PubMed

    Hussain, Musaddeq

    2015-11-10

    Chinese hamster ovary (CHO) cells are the host cell of choice for manufacturing of monoclonal antibody (mAb) drugs in the biopharmaceutical industry. Host cell DNA is an impurity of such manufacturing process and must be controlled and monitored in order to ensure drug purity and safety. A conventional method for quantification of host residual DNA in drug requires extraction of DNA from the mAb drug substance with subsequent quantification of the extracted DNA using real-time PCR (qPCR). Here we report a method where the DNA extraction step is eliminated prior to qPCR. In this method, which we have named 'direct resDNA qPCR', the mAb drug substance is digested with a protease called KAPA in a 96-well PCR plate, the protease in the digest is then denatured at high temperature, qPCR reagents are added to the resultant reaction wells in the plate along with standards and controls in other wells of the same plate, and the plate subjected to qPCR for analysis of residual host DNA in the samples. This direct resDNA qPCR method for CHO is sensitive to 5.0fg of DNA with high precision and accuracy and has a wide linear range of determination. The method has been successfully tested with four mAbs drug, two IgG1 and two IgG4. Both the purified drug substance as well as a number of process intermediate samples, e.g., bioreactor harvest, Protein A column eluate and ion-exchange column eluates were tested. This method simplifies the residual DNA quantification protocol, reduces time of analysis and leads to increased assay sensitivity and development of automated high-throughput methods. PMID:25850374

  4. A Novel Antibody Engineering Strategy for Making Monovalent Bispecific Heterodimeric IgG Antibodies by Electrostatic Steering Mechanism*

    PubMed Central

    Liu, Zhi; Leng, Esther C.; Gunasekaran, Kannan; Pentony, Martin; Shen, Min; Howard, Monique; Stoops, Janelle; Manchulenko, Kathy; Razinkov, Vladimir; Liu, Hua; Fanslow, William; Hu, Zhonghua; Sun, Nancy; Hasegawa, Haruki; Clark, Rutilio; Foltz, Ian N.; Yan, Wei

    2015-01-01

    Producing pure and well behaved bispecific antibodies (bsAbs) on a large scale for preclinical and clinical testing is a challenging task. Here, we describe a new strategy for making monovalent bispecific heterodimeric IgG antibodies in mammalian cells. We applied an electrostatic steering mechanism to engineer antibody light chain-heavy chain (LC-HC) interface residues in such a way that each LC strongly favors its cognate HC when two different HCs and two different LCs are co-expressed in the same cell to assemble a functional bispecific antibody. We produced heterodimeric IgGs from transiently and stably transfected mammalian cells. The engineered heterodimeric IgG molecules maintain the overall IgG structure with correct LC-HC pairings, bind to two different antigens with comparable affinity when compared with their parental antibodies, and retain the functionality of parental antibodies in biological assays. In addition, the bispecific heterodimeric IgG derived from anti-HER2 and anti-EGF receptor (EGFR) antibody was shown to induce a higher level of receptor internalization than the combination of two parental antibodies. Mouse xenograft BxPC-3, Panc-1, and Calu-3 human tumor models showed that the heterodimeric IgGs strongly inhibited tumor growth. The described approach can be used to generate tools from two pre-existent antibodies and explore the potential of bispecific antibodies. The asymmetrically engineered Fc variants for antibody-dependent cellular cytotoxicity enhancement could be embedded in monovalent bispecific heterodimeric IgG to make best-in-class therapeutic antibodies. PMID:25583986

  5. A novel antibody engineering strategy for making monovalent bispecific heterodimeric IgG antibodies by electrostatic steering mechanism.

    PubMed

    Liu, Zhi; Leng, Esther C; Gunasekaran, Kannan; Pentony, Martin; Shen, Min; Howard, Monique; Stoops, Janelle; Manchulenko, Kathy; Razinkov, Vladimir; Liu, Hua; Fanslow, William; Hu, Zhonghua; Sun, Nancy; Hasegawa, Haruki; Clark, Rutilio; Foltz, Ian N; Yan, Wei

    2015-03-20

    Producing pure and well behaved bispecific antibodies (bsAbs) on a large scale for preclinical and clinical testing is a challenging task. Here, we describe a new strategy for making monovalent bispecific heterodimeric IgG antibodies in mammalian cells. We applied an electrostatic steering mechanism to engineer antibody light chain-heavy chain (LC-HC) interface residues in such a way that each LC strongly favors its cognate HC when two different HCs and two different LCs are co-expressed in the same cell to assemble a functional bispecific antibody. We produced heterodimeric IgGs from transiently and stably transfected mammalian cells. The engineered heterodimeric IgG molecules maintain the overall IgG structure with correct LC-HC pairings, bind to two different antigens with comparable affinity when compared with their parental antibodies, and retain the functionality of parental antibodies in biological assays. In addition, the bispecific heterodimeric IgG derived from anti-HER2 and anti-EGF receptor (EGFR) antibody was shown to induce a higher level of receptor internalization than the combination of two parental antibodies. Mouse xenograft BxPC-3, Panc-1, and Calu-3 human tumor models showed that the heterodimeric IgGs strongly inhibited tumor growth. The described approach can be used to generate tools from two pre-existent antibodies and explore the potential of bispecific antibodies. The asymmetrically engineered Fc variants for antibody-dependent cellular cytotoxicity enhancement could be embedded in monovalent bispecific heterodimeric IgG to make best-in-class therapeutic antibodies. PMID:25583986

  6. Antibodies binding granulocyte-macrophage colony stimulating factor produced by cord blood-derived B cell lines immortalized by Epstein-Barr virus in vitro.

    PubMed

    Revoltella, R P; Laricchia Robbio, L; Liberati, A M; Reato, G; Foa, R; Funaro, A; Vinante, F; Pizzolo, G

    2000-09-15

    We detected natural antibodies (auto-Abs) binding human granulocyte-macrophage colony stimulating factor (GM-CSF) in umbilical cord blood (CB) (23 of 94 samples screened) and peripheral blood of women at the end of pregnancy (6 of 42 samples tested). To demonstrate that Abs detected in CB were produced by the fetus, CB mononuclear cells were infected with Epstein-Barr virus in vitro. Ten cell lines producing constitutively anti-recombinant human GM-CSF (rhGM-CSF) Abs were isolated and characterized. These cells displayed a male karyotype, an early activated B cell phenotype, coexpressed surface IgM and IgD, and secreted only IgM with prevailing lambda clonal restriction. Specific cell surface binding of biotinylated rhGM-CSF and high-level anti-rhGM-CSF IgM Ab production were typical features of early cell cultures. In late cell passages the frequency of more undifferentiated B cells increased. Serum Abs of either maternal or fetal origin or Abs produced in culture did not affect the granulocyte and macrophage colony stimulating activity of rhGM-CSF from bone marrow progenitors in soft agar, suggesting that the Abs produced were nonneutralizing. PMID:11069719

  7. Effects of cytotoxin-associated gene A (CagA) positive Helicobacter pylori infection on anti-platelet glycoprotein antibody producing B cells in patients with primary idiopathic thrombocytopenic purpura (ITP)

    PubMed Central

    Cheng, Yuan-Shan; Kuang, Li-Ping; Zhuang, Chun-Lan; Jiang, Jia-Dian; Shi, Man

    2015-01-01

    Objective: To explore the effects of cytotoxin-associated gene A (CagA) positive Helicobacter pylori (H. pylori or HP) infection on circulating B cells producing specific platelet glycoprotein antibodies and the association between therapeutic outcomes in primary idiopathic thrombocytopenic purpura (ITP) patients. Methods: A total of 76 newly diagnosed primary ITP patients were included in the study which was conducted at the first affiliated hospital of Shantou University Medical college, in Shantou city China, between January 2013 and January 2014. These patients were tested for H. pylori infection by 13C urea breath test and for anti-CagA antibody in H. pylori positive cases by enzyme-linked immunosorbent assay (ELISA) method. Anti-GPIb and anti-GPIIb/IIIa antibody-producing B cells were measured using an enzyme-linked immunospot (ELISPOT) assay in all ITP patients and 30 controls. Anti-nuclear antibody (ANA) was also detected in ITP patients. Results: The numbers of anti-GPIIb/IIIa antibody-producing B cells in HP+CagA+ patients were higher than in HP+CagA- or HP- patients. However, anti-GPIb antibody-producing B cells were found higher in HP- patients. Analysis of treatment outcomes showed that a therapeutic response was more likely in patients presenting anti-GPIIb/IIIa B cells, but the poor response was found to be associated with anti-GPIb B cells and ANA presences. Conclusion: CagA antigen of H. pylori may induce anti-GPIIb/IIIa antibodies production by a molecular mimicry mechanism. Anti-GPIIb/IIIa and anti-GPIb antibody producing B Cells detection is useful for predicting treatment effects of primary ITP. PMID:25878627

  8. Epitope map of human immunodeficiency virus type 1 gp41 derived from 47 monoclonal antibodies produced by immunization with oligomeric envelope protein.

    PubMed Central

    Earl, P L; Broder, C C; Doms, R W; Moss, B

    1997-01-01

    The biologically relevant form of the human immunodeficiency virus type 1 (HIV-1) envelope (Env) glycoprotein is oligomeric, with the major points of contact between oligomeric partners located in the ectodomain of gp41. To identify and map conserved epitopes and regions in gp41 where structure is influenced by quaternary interactions, we used a panel of 38 conformation-dependent and 9 conformation-independent anti-gp41 monoclonal antibodies (MAbs) produced by immunization of mice with oligomeric Env protein. By cross-competition experiments using these MAbs and several others previously described, six distinct antigenic determinants were identified and mapped. Three of these determinants are conformational in nature and dependent in part on Env oligomeric structure. MAbs to two of these determinants were broadly cross-reactive with Env proteins derived from primary virus strains. The prevalence of antibodies in HIV-1-positive human sera to the antigenic determinants was determined by the ability of such sera to block binding of MAbs to Env protein. Strong blocking activity that correlated with cross-reactivity was found. PMID:9060620

  9. Characterization of N-Linked Glycosylation in a Monoclonal Antibody Produced in NS0 Cells Using Capillary Electrophoresis with Laser-Induced Fluorescence Detection

    PubMed Central

    Hamm, Melissa; Wang, Yang; Rustandi, Richard R.

    2013-01-01

    The N-linked glycosylation in recombinant monoclonal antibodies (mAb) occurs at Asn297 on the Fc region in the CH2 domain. Glycosylation heterogeneities have been well documented to affect biological activities such as antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) through their interaction with Fc-receptors. Hence, it is critical to monitor and characterize the N-linked glycosylation profile in a therapeutic protein such as a mAb for product consistency. In one approach, the glycans are first released from the mAb using an enzyme specific digestion, such as Protein N-Glycosidase F (PNGase) and subsequently they are labeled using a fluorophore, for example, 8-aminopyrene-1,3,6-trisulfonic acid (APTS) . Here we have applied this approach and used Capillary Electrophoresis with Laser-Induced Fluorescence detection (CE-LIF) to analyze a recombinant mAb produced in murine myeloma (NS0) cells. The technique provides short analysis times, efficient separations, and high sensitivity. CE-LIF peak identification was done by a combination of glycan standards and treatment with various exoglycosidases. Furthermore, the APTS-labeled glycans were also analyzed using hydrophilic interaction chromatography (HILIC) high performance liquid chromatography (HPLC) to aid identification of minor peaks by sample collection and off-line mass spectrometry (MS) analysis. PMID:24276024

  10. A Polyclonal Antibody Based Immunoassay Detects Seven Subtypes of Shiga Toxin 2 Produced by Escherichia coli in Human and Environmental Samples

    PubMed Central

    He, Xiaohua; Patfield, Stephanie; Hnasko, Robert; Rasooly, Reuven; Mandrell, Robert E.

    2013-01-01

    Background Shiga toxin-producing Escherichia coli (STEC) are frequent causes of severe human diseases ranging from diarrhea to hemolytic uremic syndrome. The existing strategy for detection of STEC relies on the unique sorbitol-negative fermentation property of the O157 strains, the most commonly identified serotype has been E. coli O157. It is becoming increasingly evident, however, that numerous non-O157 STEC serotypes also cause outbreaks and severe illnesses. It is necessary to have new methods that are capable of detecting all STEC strains. Methods and Findings Here we describe the development of a sandwich ELISA assay for detecting both O157 and non-O157 STECs by incorporating a novel polyclonal antibody (pAb) against Stx2. The newly established immunoassay was capable of detecting Stx2a spiked in environmental samples with a limit of detection between 10 and 100 pg/mL in soil and between 100 and 500 pg/mL in feces. When applied to 36 bacterial strains isolated from human and environmental samples, this assay detected Stx2 in all strains that were confirmed to be stx2-positive by real-time PCR, demonstrating a 100% sensitivity and specificity. Conclusions The sandwich ELISA developed in this study will enable any competent laboratory to identify and characterize Stx2-producing O157 and non-O157 strains in human and environmental samples, resulting in rapid diagnosis and patient care. The results of epitope mapping from this study will be useful for further development of a peptide-based antibody and vaccine. PMID:24146860

  11. A novel approach for the simultaneous quantification of a therapeutic monoclonal antibody in serum produced from two distinct host cell lines

    PubMed Central

    Geist, Brian J.; Davis, Darryl; McIntosh, Thomas; Yang, Tong-Yuan; Goldberg, Kenneth; Han, Chao; Pendley, Charles; Davis, Hugh M.

    2013-01-01

    Therapeutic monoclonal antibodies (mAbs) possess a high degree of heterogeneity associated with the cell expression system employed in manufacturing, most notably glycosylation. Traditional immunoassay formats used to quantify therapeutic mAbs are unable to discriminate between different glycosylation patterns that may exist on the same protein amino acid sequence. Mass spectrometry provides a technique to distinguish specific glycosylation patterns of the therapeutic antibody within the same sample, thereby allowing for simultaneous quantification of the same mAb with different glycosylation patterns. Here we demonstrate a two-step approach to successfully differentiate and quantify serum mixtures of a recombinant therapeutic mAb produced in two different host cell lines (CHO vs. Sp2/0) with distinct glycosylation profiles. Glycosylation analysis of the therapeutic mAb, CNTO 328 (siltuximab), was accomplished through sample pretreatment consisting of immunoaffinity purification (IAP) and enrichment, followed by liquid chromatography (LC) and mass spectrometry (MS). LC-MS analysis was used to determine the percentage of CNTO 328 in the sample derived from either cell line based on the N-linked G1F oligosaccharide on the mAb. The relative amount of G1F derived from each cell line was compared with ratios of CNTO 328 reference standards prepared in buffer. Glycoform ratios were converted to concentrations using an immunoassay measuring total CNTO 328 that does not distinguish between the different glycoforms. Validation of the IAP/LC-MS method included intra-run and inter-run variability, method sensitivity and freeze-thaw stability. The method was accurate (%bias range = -7.30–13.68%) and reproducible (%CV range = 1.49–10.81%) with a LOQ of 2.5 μg/mL. PMID:23182963

  12. Prevention and treatment of Clostridium perfringens epsilon toxin intoxication in mice with a neutralizing monoclonal antibody (c4D7) produced in Nicotiana benthamiana.

    PubMed

    Garcia, J P; Beingesser, J; Bohorov, O; Bohorova, N; Goodman, C; Kim, D; Pauly, M; Velasco, J; Whaley, K; Zeitlin, L; Roy, C J; Uzal, F A

    2014-09-01

    Epsilon toxin (ETX), produced by Clostridium perfringens types B and D, is among the most lethal toxins known. ETX is a potential bioterrorism threat that was listed as a Category B agent by the U.S. Centers for Disease Control until 2012 and it still remains a toxin of interest for several government agencies. We produced a monoclonal antibody (MAb) against ETX (ETX MAb c4D7) in Nicotiana benthamiana and characterized its preventive and therapeutic efficacy in mice. The ETX preparation used was highly lethal for mice (LD50 = 1.6 μg/kg) and resulted in a mean time from inoculation to death of 18 and 180 min when administered intravenously or intraperitoneally, respectively. High lethal challenge resulted in dramatic increases of a variety of pro-inflammatory cytokines in serum, while lower, but still lethal doses, did not elicit such responses. ETX MAb c4D7 was highly effective prophylactically (ED50 = 0.3 mg/kg; ED100 = 0.8 mg/kg) and also provided protection when delivered 15-30 min post-ETX intoxication. These data suggest that ETX MAb c4D7 may have use as a pre- and post-exposure treatment for ETX intoxication. PMID:24950050

  13. Coxsackievirus A16-like particles produced in Pichia pastoris elicit high-titer neutralizing antibodies and confer protection against lethal viral challenge in mice.

    PubMed

    Zhang, Chao; Liu, Qingwei; Ku, Zhiqiang; Hu, Yang; Ye, Xiaohua; Zhang, Yingyi; Huang, Zhong

    2016-05-01

    Coxsackievirus A16 (CA16) is a major causative agent of hand, foot and mouse disease (HFMD) which has been affecting millions of young children annually in the Asia-Pacific region over the last seven years. However, no commercial CA16 vaccines are currently available. In the present study, we investigated the expression of virus-like particles (VLPs) of CA16 in Pichia pastoris yeast and their immunogenicity and protective efficacy in mice. We found that CA16-VLPs could be produced at relatively high levels in P. pastoris yeast transformed with a construct co-expressing the P1 and 3CD proteins of CA16. Mice immunized with the yeast-derived CA16-VLPs produced high-titer serum antibodies with potent neutralization effect specifically on CA16. More importantly, passive immunization with the yeast-derived VLPs fully protected neonatal mice against CA16 lethal challenge in both antisera transfer and maternal immunization experiments. Collectively, our results demonstrate that P. pastoris-derived CA16-VLPs represent a promising CA16 vaccine candidate with proven preclinical efficacy and desirable traits for manufacturing at industrial scale. PMID:26902108

  14. Prevention and treatment of Clostridium perfringens epsilon toxin intoxication in mice with a neutralizing monoclonal antibody (c4D7) produced in Nicotiana benthamiana

    PubMed Central

    Garcia, J.P.; Beingesser, J.; Bohorov, O.; Bohorova, N.; Goodman, C.; Kim, D.; Pauly, M.; Velasco, J.; Whaley, K.; Zeitlin, L.; Roy, C.J.; Uzal, F.A.

    2014-01-01

    Epsilon toxin (ETX), produced by Clostridium perfringens types B and D, is among the most lethal toxins known. ETX is a potential bioterrorism threat that was listed as a Category B agent by the U.S. Centers for Disease Control until 2012 and it still remains a toxin of interest for several government agencies. We produced a monoclonal antibody (MAb) against ETX (ETX MAb c4D7) in Nicotiana benthamiana and characterized its preventive and therapeutic efficacy in mice. The ETX preparation used was highly lethal for mice (LD50 =1.6 μg/kg) and resulted in a mean time from inoculation to death of 18 and 180 minutes when administered intravenously or intraperitoneally, respectively. High lethal challenge resulted in dramatic increases of a variety of pro-inflammatory cytokines in serum, while lower, but still lethal doses, did not elicit such responses. ETX MAb c4D7 was highly effective prophylactically (ED50 = 0.3 mg/kg; ED100 = 0.8 mg/kg) and also provided protection when delivered 15-30 minutes post-ETX intoxication. These data suggest that ETX MAb c4D7 may have use as a pre- and post-exposure treatment for ETX intoxication. PMID:24950050

  15. Antibodies and Selection of Monoclonal Antibodies.

    PubMed

    Hanack, Katja; Messerschmidt, Katrin; Listek, Martin

    2016-01-01

    Monoclonal antibodies are universal binding molecules with a high specificity for their target and are indispensable tools in research, diagnostics and therapy. The biotechnological generation of monoclonal antibodies was enabled by the hybridoma technology published in 1975 by Köhler and Milstein. Today monoclonal antibodies are used in a variety of applications as flow cytometry, magnetic cell sorting, immunoassays or therapeutic approaches. First step of the generation process is the immunization of the organism with appropriate antigen. After a positive immune response the spleen cells are isolated and fused with myeloma cells in order to generate stable, long-living antibody-producing cell lines - hybridoma cells. In the subsequent identification step the culture supernatants of all hybridoma cells are screened weekly for the production of the antibody of interest. Hybridoma cells producing the antibody of interest are cloned by limited dilution till a monoclonal hybridoma is found. This is a very time-consuming and laborious process and therefore different selection strategies were developed since 1975 in order to facilitate the generation of monoclonal antibodies. Apart from common automation of pipetting processes and ELISA testing there are some promising approaches to select the right monoclonal antibody very early in the process to reduce time and effort of the generation. In this chapter different selection strategies for antibody-producing hybridoma cells are presented and analysed regarding to their benefits compared to conventional limited dilution technology. PMID:27236550

  16. Using simple models to describe the kinetics of growth, glucose consumption, and monoclonal antibody formation in naive and infliximab producer CHO cells.

    PubMed

    López-Meza, Julián; Araíz-Hernández, Diana; Carrillo-Cocom, Leydi Maribel; López-Pacheco, Felipe; Rocha-Pizaña, María Del Refugio; Alvarez, Mario Moisés

    2016-08-01

    Despite their practical and commercial relevance, there are few reports on the kinetics of growth and production of Chinese hamster ovary (CHO) cells-the most frequently used host for the industrial production of therapeutic proteins. We characterize the kinetics of cell growth, substrate consumption, and product formation in naive and monoclonal antibody (mAb) producing recombinant CHO cells. Culture experiments were performed in 125 mL shake flasks on commercial culture medium (CD Opti CHO™ Invitrogen, Carlsbad, CA, USA) diluted to different glucose concentrations (1.2-4.8 g/L). The time evolution of cell, glucose, lactic acid concentration and monoclonal antibody concentrations was monitored on a daily basis for mAb-producing cultures and their naive counterparts. The time series were differentiated to calculate the corresponding kinetic rates (rx = d[X]/dt; rs = d[S]/dt; rp = d[mAb]/dt). Results showed that these cell lines could be modeled by Monod-like kinetics if a threshold substrate concentration value of [S]t = 0.58 g/L (for recombinant cells) and [S]t = 0.96 g/L (for naïve cells), below which growth is not observed, was considered. A set of values for μmax, and Ks was determined for naive and recombinant cell cultures cultured at 33 and 37 °C. The yield coefficient (Yx/s) was observed to be a function of substrate concentration, with values in the range of 0.27-1.08 × 10(7) cell/mL and 0.72-2.79 × 10(6) cells/mL for naive and recombinant cultures, respectively. The kinetics of mAb production can be described by a Luedeking-Piret model (d[mAb]/dt = αd[X]/dt + β[X]) with values of α = 7.65 × 10(-7) µg/cell and β = 7.68 × 10(-8) µg/cell/h for cultures conducted in batch-agitated flasks and batch and instrumented bioreactors operated in batch and fed-batch mode. PMID:26091615

  17. Developing recombinant antibodies for biomarker detection

    SciTech Connect

    Baird, Cheryl L.; Fischer, Christopher J.; Pefaur, Noah B.; Miller, Keith D.; Kagen, Jacob; Srivastava, Sudhir; Rodland, Karin D.

    2010-10-01

    Monoclonal antibodies (mAbs) have an essential role in biomarker validation and diagnostic assays. A barrier to pursuing these applications is the reliance on immunization and hybridomas to produce mAbs, which is time-consuming and may not yield the desired mAb. We recommend a process flow for affinity reagent production that utilizes combinatorial protein display systems (eg, yeast surface display or phage display) rather than hybridomas. These systems link a selectable phenotype-binding conferred by an antibody fragment-with a means for recovering the encoding gene. Recombinant libraries obtained from immunizations can produce high-affinity antibodies (<10 nM) more quickly than other methods. Non-immune libraries provide an alternate route when immunizations are not possible, or when suitable mAbs are not recovered from an immune library. Directed molecular evolution (DME) is an integral part of optimizing mAbs obtained from combinatorial protein display, but can also be used on hybridoma-derived mAbs. Variants can easily be obtained and screened to increase the affinity of the parent mAb (affinity maturation). We discuss examples where DME has been used to tailor affinity reagents to specific applications. Combinatorial protein display also provides an accessible method for identifying antibody pairs, which are necessary for sandwich-type diagnostic assays.

  18. Monoclonal antibody that inhibits infection of HeLa and rhabdomyosarcoma cells by selected enteroviruses through receptor blockade

    SciTech Connect

    Crowell, R.L.; Field, A.K.; Schleif, W.A.; Long, W.L.; Colonno, R.J.; Mapoles, J.E.; Emini, E. A.

    1986-02-01

    BALB/c mice were immunized with HeLa cells, and their spleen cells were fused with myeloma cells to produce hybridomas. Initial screening of culture fluids from 800 fusion products in a cell protection assay against coxsackievirus B3 (CB3) and the CB3-RD virus variant yielded five presumptive monoclonal antibodies with three specificities: (i) protection against CB3 on HeLa, (ii) protection against CB3-RD on rhabdomyosarcoma (RD) cells, and (iii) protection against both viruses on the respective cells. Only one of the monoclonal antibodies (with dual specificity) survived two subclonings and was studied in detail. The antibody was determined to have an immunoglobulin G2a isotype and protected cells by blockade of cellular receptors, since attachment of (/sup 35/S)methionine-labeled CB3 was inhibited by greater than 90%. The monoclonal antibody protected HeLa cells against infection by CB1, CB3, CB5, echovirus 6, and coxsackievirus A21 and RD cells against CB1-RD, CB3-RD, and CB5-Rd virus variants. The monoclonal antibody did not protect either cell type against 16 other immunotypes of picornaviruses. The monoclonal antibody produced only positive fluorescence on those cells which were protected against infection, and /sup 125/I-labeled antibody confirmed the specific binding to HeLa and RD cells. The results suggest that this monoclonal antibody possesses some of the receptor specificity of the group B coxsackieviruses.

  19. Haemagglutination induced by Bordetella pertussis filamentous haemagglutinin adhesin (FHA) is inhibited by antibodies produced against FHA(430-873) fragment expressed in Lactobacillus casei.

    PubMed

    Colombi, Débora; Oliveira, Maria L S; Campos, Ivana B; Monedero, Vicente; Pérez-Martinez, Gaspar; Ho, Paulo L

    2006-12-01

    Filamentous haemagglutinin adhesin (FHA) is an important virulence factor from Bordetella pertussis related to the adhesion and spread of the bacteria through the respiratory tract. Three distinct domains have been characterized in mature FHA, and among them, the FHA(442-863) fragment was suggested to be responsible for the heparin-binding activity. In this study, we cloned the gene encoding the HEP fragment (FHA(430-873)) in a Lactobacillus casei-inducible expression vector based on the lactose operon. The recombinant bacteria, transformed with the resulting construct (L. casei-HEP), were able to express the heterologous protein depending on the sugar added to the culture. Subcutaneous inoculation of L. casei-HEP in Balb/C mice, using the cholera toxin B subunit as adjuvant, induced systemic anti-HEP antibodies that were able to inhibit in vitro erythrocyte haemagglutination induced by FHA. This is the first example of a B. pertussis antigen produced in lactic acid bacteria and opens new perspectives for alternative vaccine strategies against whooping cough. PMID:17106803

  20. A plant-produced Pfs25 VLP malaria vaccine candidate induces persistent transmission blocking antibodies against Plasmodium falciparum in immunized mice.

    PubMed

    Jones, R Mark; Chichester, Jessica A; Mett, Vadim; Jaje, Jennifer; Tottey, Stephen; Manceva, Slobodanka; Casta, Louis J; Gibbs, Sandra K; Musiychuk, Konstantin; Shamloul, Moneim; Norikane, Joey; Mett, Valentina; Streatfield, Stephen J; van de Vegte-Bolmer, Marga; Roeffen, Will; Sauerwein, Robert W; Yusibov, Vidadi

    2013-01-01

    Malaria transmission blocking vaccines (TBVs) are considered an effective means to control and eventually eliminate malaria. The Pfs25 protein, expressed predominantly on the surface of the sexual and sporogonic stages of Plasmodium falciparum including gametes, zygotes and ookinetes, is one of the primary targets for TBV. It has been demonstrated that plants are an effective, highly scalable system for the production of recombinant proteins, including virus-like particles (VLPs). We engineered VLPs (Pfs25-CP VLP) comprising Pfs25 fused to the Alfalfa mosaic virus coat protein (CP) and produced these non-enveloped hybrid VLPs in Nicotiana benthamiana plants using a Tobacco mosaic virus-based 'launch' vector. Purified Pfs25-CP VLPs were highly consistent in size (19.3±2.4 nm in diameter) with an estimated 20-30% incorporation of Pfs25 onto the VLP surface. Immunization of mice with one or two doses of Pfs25-CP VLPs plus Alhydrogel® induced serum antibodies with complete transmission blocking activity through the 6 month study period. These results support the evaluation of Pfs25-CP VLP as a potential TBV candidate and the feasibility of the 'launch' vector technology for the production of VLP-based recombinant vaccines against infectious diseases. PMID:24260245

  1. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2011-08-16

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  2. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2011-05-31

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  3. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2008-12-02

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  4. Variant Humicola grisea CBH1.1

    DOEpatents

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2012-08-07

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  5. Variant Humicola grisea CBH1.1

    SciTech Connect

    Goedegeburr, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2013-02-19

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  6. Variant Humicola grisea CBH1.1

    SciTech Connect

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Larenas, Edmund

    2014-03-18

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  7. Variant humicola grisea CBH1.1

    SciTech Connect

    Goedegebuur, Frits; Gualfetti, Peter; Mitchinson, Colin; Edmund, Larenas

    2014-09-09

    Disclosed are variants of Humicola grisea Cel7A (CBH1.1), H. jecorina CBH1 variant or S. thermophilium CBH1, nucleic acids encoding the same and methods for producing the same. The variant cellulases have the amino acid sequence of a glycosyl hydrolase of family 7A wherein one or more amino acid residues are substituted.

  8. Development of recombinant human IgA for anticardiolipin antibodies assay standardization.

    PubMed

    Knappik, Achim; Capuano, Francesco; Frisch, Christian; Ylera, Francisco; Bonelli, Fabrizio

    2009-09-01

    Controls and calibrators in autoimmune assays are typically developed from patient sera. However, the use of sera is accompanied by a number of disadvantages, such as lack of monospecificity, lack of assay comparability, and supply limitations. Ideally, the control reagent would be an antigen-specific human monoclonal antibody preparation that is defined and pure, easy to produce without any supply limitations, and of defined isotype (IgG, IgM, or IgA). The generation of antigen-specific human monoclonal antibodies has been complicated, but recent advances in development of fully human antibodies by means of in vitro antibody gene library selection has opened a way for the isolation of human antibodies to virtually any antigen, including self-antigens. Such antibodies can be converted to any isotype by gene cloning. Here we developed a set of human monoclonal IgA antibodies specific for the cardiolipin-beta2-glycoprotein 1 complex, using the HuCAL technology. We evaluated the IgA variants of those antibodies for their use as standards in IgA anticardiolipin antibody assays and compared these reagents with serum controls. Such recombinant antibodies may ultimately replace patient sera as assay control and calibration reagents. PMID:19758150

  9. Low-affinity IgM antibodies lacking somatic hypermutations are produced in the secondary response of C57BL/6 mice to (4-hydroxy-3-nitrophenyl)acetyl hapten.

    PubMed

    Murakami, Akikazu; Moriyama, Hayato; Osako-Kabasawa, Mina; Endo, Kanako; Nishimura, Miyuki; Udaka, Keiko; Muramatsu, Masamichi; Honjo, Tasuku; Azuma, Takachika; Shimizu, Takeyuki

    2014-04-01

    Class-switched memory B cells, which are generated through the processes of somatic hypermutation (SHM) and affinity-based selection in germinal centers, contribute to the production of affinity-matured IgG antibodies in the secondary immune response. However, changes in the affinity of IgM antibodies during the immune response have not yet been studied, although IgM(+) memory B cells have been shown to be generated. In order to understand the relationship between IgM affinity and the recall immune response, we prepared hybridomas producing anti-(4-hydroxy-3-nitrophenyl)acetyl (NP) IgM antibodies from C57BL/6 mice and from activation-induced cytidine deaminase (AID)-deficient mice. Binding analysis by ELISA showed that mAbs obtained from the secondary immune response contained IgM mAbs with affinity lower than the affinity of mAbs obtained from the primary response. By analyzing sequences of the IgM genes of hybridomas and plasma cells, we found many unmutated VH genes. VH genes that had neither tyrosine nor glycine at position 95 were frequent. The repertoire change may correlate with the lower affinity of IgM antibodies in the secondary response. The sequence and affinity changes in IgM antibodies were shown to be independent of SHM by analyzing hybridomas from AID-deficient mice. A functional assay revealed a reciprocal relationship between affinity and complement-dependent hemolytic activity toward NP-conjugated sheep RBCs; IgM antibodies with lower affinities had higher hemolytic activity. These findings indicate that lower affinity IgM antibodies with enhanced complement activation function are produced in the secondary immune response. PMID:24285827

  10. Prevalence of subtilase cytotoxin-encoding subAB variants among Shiga toxin-producing Escherichia coli strains isolated from wild ruminants and sheep differs from that of cattle and pigs and is predominated by the new allelic variant subAB2-2.

    PubMed

    Nüesch-Inderbinen, Magdalena T; Funk, Joschua; Cernela, Nicole; Tasara, Taurai; Klumpp, Jochen; Schmidt, Herbert; Stephan, Roger

    2015-01-01

    Subtilase cytotoxin (SubAB) is an AB5 toxin produced by Shiga toxin (Stx)-producing Escherichia coli (STEC) strains usually lacking the eae gene product intimin. Three allelic variants of SubAB encoding genes have been described: subAB1, located on a plasmid, subAB2-1, located on the pathogenicity island SE-PAI and subAB2-2 located in an outer membrane efflux protein (OEP) region. SubAB is becoming increasingly recognized as a toxin potentially involved in human pathogenesis. Ruminants and cattle have been identified as reservoirs of subAB-positive STEC. The presence of the three subAB allelic variants was investigated by PCR for 152 STEC strains originating from chamois, ibex, red deer, roe deer, cattle, sheep and pigs. Overall, subAB genes were detected in 45.5% of the strains. Prevalence was highest for STEC originating from ibex (100%), chamois (92%) and sheep (65%). None of the STEC of bovine or of porcine origin tested positive for subAB. None of the strains tested positive for subAB1. The allelic variant subAB2-2 was detected the most commonly, with 51.4% possessing subAb2-1 together with subAB2-2. STEC of ovine origin, serotypes O91:H- and O128:H2, the saa gene, which encodes for the autoagglutinating adhesin and stx2b were significantly associated with subAB-positive STEC. Our results suggest that subAB2-1 and subAB2-2 is widespread among STEC from wild ruminants and sheep and may be important as virulence markers in STEC pathogenic to humans. PMID:25488108

  11. Expression in systemic lupus erythematosus of an idiotype common to DNA-binding and nonbinding monoclonal antibodies produced by normal human lymphoid cells.

    PubMed Central

    Cairns, E; Massicotte, H; Bell, D A

    1989-01-01

    Rabbit antiserum raised against a normal-derived monoclonal anti-DNA antibody KIM 4.6.3 (IgM lambda) was used for idiotype analyses. This anti-serum (anti-4.6.3 ID) was rendered specific for KIM 4.6.3 idiotype (4.6.3 ID) by absorption with normal human IgM and IgG. The specificity of anti-4.6.3 was shown by its ability to bind to KIM 4.6.3 antibody but not to normal human IgM and IgG, by inhibition of anti-4.6.3 ID reactivity with KIM 4.6.3 antibody by the homologous monoclonal antibody and by the ability of anti-4.6.3 ID to inhibit the binding of single stranded DNA with KIM 4.6.3 antibody. The 4.6.3 ID was found to be commonly expressed since it was detected among 33% (10/30) DNA and 32% (23/72) non-DNA-reactive monoclonal antibodies that were obtained from five different unrelated normal individuals. The binding to ssDNA of the majority of idiotype positive anti-DNA antibodies however was not blocked by anti-4.6.3 ID suggesting that among these other monoclonal antibodies its expression is outside of the antigen binding site. The 4.6.3 ID, which was present among some normal-derived monoclonal IgM molecules was also found at a high frequency (90%) in the sera of patients with systemic lupus erythematosus (SLE) but only at a low frequency (24%) and concentration in normal sera. The level of 4.6.3 ID in SLE did not correlate with serum IgM and IgG nor with anti-DNA antibody concentrations. Idiotypic relatedness between SLE serum antibodies and monoclonal anti-DNA antibodies of normals implies the existence of a cross-reactive idiotype family and implies that a conserved common gene or closely related genes exist in the germ line encoding these 4.6.3 ID positive antibodies some of which are not exclusively associated with nucleic acid reactivity. The expression of these germ line genes in vivo thus distinguishes SLE from normals. PMID:2493481

  12. Staphylococcus aureus adapts to oxidative stress by producing H2O2-resistant small-colony variants via the SOS response.

    PubMed

    Painter, Kimberley L; Strange, Elizabeth; Parkhill, Julian; Bamford, Kathleen B; Armstrong-James, Darius; Edwards, Andrew M

    2015-05-01

    The development of chronic and recurrent Staphylococcus aureus infections is associated with the emergence of slow-growing mutants known as small-colony variants (SCVs), which are highly tolerant of antibiotics and can survive inside host cells. However, the host and bacterial factors which underpin SCV emergence during infection are poorly understood. Here, we demonstrate that exposure of S. aureus to sublethal concentrations of H2O2 leads to a specific, dose-dependent increase in the population frequency of gentamicin-resistant SCVs. Time course analyses revealed that H2O2 exposure caused bacteriostasis in wild-type cells during which time SCVs appeared spontaneously within the S. aureus population. This occurred via a mutagenic DNA repair pathway that included DNA double-strand break repair proteins RexAB, recombinase A, and polymerase V. In addition to triggering SCV emergence by increasing the mutation rate, H2O2 also selected for the SCV phenotype, leading to increased phenotypic stability and further enhancing the size of the SCV subpopulation by reducing the rate of SCV reversion to the wild type. Subsequent analyses revealed that SCVs were significantly more resistant to the toxic effects of H2O2 than wild-type bacteria. With the exception of heme auxotrophs, gentamicin-resistant SCVs displayed greater catalase activity than wild-type bacteria, which contributed to their resistance to H2O2. Taken together, these data reveal a mechanism by which S. aureus adapts to oxidative stress via the production of a subpopulation of H2O2-resistant SCVs with enhanced catalase production. PMID:25690100

  13. Staphylococcus aureus Adapts to Oxidative Stress by Producing H2O2-Resistant Small-Colony Variants via the SOS Response

    PubMed Central

    Painter, Kimberley L.; Strange, Elizabeth; Bamford, Kathleen B.; Armstrong-James, Darius

    2015-01-01

    The development of chronic and recurrent Staphylococcus aureus infections is associated with the emergence of slow-growing mutants known as small-colony variants (SCVs), which are highly tolerant of antibiotics and can survive inside host cells. However, the host and bacterial factors which underpin SCV emergence during infection are poorly understood. Here, we demonstrate that exposure of S. aureus to sublethal concentrations of H2O2 leads to a specific, dose-dependent increase in the population frequency of gentamicin-resistant SCVs. Time course analyses revealed that H2O2 exposure caused bacteriostasis in wild-type cells during which time SCVs appeared spontaneously within the S. aureus population. This occurred via a mutagenic DNA repair pathway that included DNA double-strand break repair proteins RexAB, recombinase A, and polymerase V. In addition to triggering SCV emergence by increasing the mutation rate, H2O2 also selected for the SCV phenotype, leading to increased phenotypic stability and further enhancing the size of the SCV subpopulation by reducing the rate of SCV reversion to the wild type. Subsequent analyses revealed that SCVs were significantly more resistant to the toxic effects of H2O2 than wild-type bacteria. With the exception of heme auxotrophs, gentamicin-resistant SCVs displayed greater catalase activity than wild-type bacteria, which contributed to their resistance to H2O2. Taken together, these data reveal a mechanism by which S. aureus adapts to oxidative stress via the production of a subpopulation of H2O2-resistant SCVs with enhanced catalase production. PMID:25690100

  14. Engineering antibody therapeutics.

    PubMed

    Chiu, Mark L; Gilliland, Gary L

    2016-06-01

    The successful introduction of antibody-based protein therapeutics into the arsenal of treatments for patients has within a few decades fostered intense innovation in the production and engineering of antibodies. Reviewed here are the methods currently used to produce antibodies along with how our knowledge of the structural and functional characterization of immunoglobulins has resulted in the engineering of antibodies to produce protein therapeutics with unique properties, both biological and biophysical, that are leading to novel therapeutic approaches. Antibody engineering includes the introduction of the antibody combining site (variable regions) into a host of architectures including bi and multi-specific formats that further impact the therapeutic properties leading to further advantages and successes in patient treatment. PMID:27525816

  15. Antibodies Directed against Shiga-Toxin Producing Escherichia coli Serotype O103 Type III Secreted Proteins Block Adherence of Heterologous STEC Serotypes to HEp-2 Cells

    PubMed Central

    Desin, Taseen S.; Townsend, Hugh G.; Potter, Andrew A.

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) serotype O103 is a zoonotic pathogen that is capable of causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. The main animal reservoir for STEC is ruminants and hence reducing the levels of this pathogen in cattle could ultimately lower the risk of STEC infection in humans. During the process of infection, STECO103 uses a Type III Secretion System (T3SS) to secrete effector proteins (T3SPs) that result in the formation of attaching and effacing (A/E) lesions. Vaccination of cattle with STEC serotype O157 T3SPs has previously been shown to be effective in reducing shedding of STECO157 in a serotype-specific manner. In this study, we tested the ability of rabbit polyclonal sera against individual STECO103 T3SPs to block adherence of the organism to HEp-2 cells. Our results demonstrate that pooled sera against EspA, EspB, EspF, NleA and Tir significantly lowered the adherence of STECO103 relative to pre-immune sera. Likewise, pooled anti-STECO103 sera were also able to block adherence by STECO157. Vaccination of mice with STECO103 recombinant proteins induced strong IgG antibody responses against EspA, EspB, NleA and Tir but not against EspF. However, the vaccine did not affect fecal shedding of STECO103 compared to the PBS vaccinated group over the duration of the experiment. Cross reactivity studies using sera against STECO103 recombinant proteins revealed a high degree of cross reactivity with STECO26 and STECO111 proteins implying that sera against STECO103 proteins could potentially provide neutralization of attachment to epithelial cells by heterologous STEC serotypes. PMID:26451946

  16. Antibodies Directed against Shiga-Toxin Producing Escherichia coli Serotype O103 Type III Secreted Proteins Block Adherence of Heterologous STEC Serotypes to HEp-2 Cells.

    PubMed

    Desin, Taseen S; Townsend, Hugh G; Potter, Andrew A

    2015-01-01

    Shiga toxin-producing Escherichia coli (STEC) serotype O103 is a zoonotic pathogen that is capable of causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in humans. The main animal reservoir for STEC is ruminants and hence reducing the levels of this pathogen in cattle could ultimately lower the risk of STEC infection in humans. During the process of infection, STECO103 uses a Type III Secretion System (T3SS) to secrete effector proteins (T3SPs) that result in the formation of attaching and effacing (A/E) lesions. Vaccination of cattle with STEC serotype O157 T3SPs has previously been shown to be effective in reducing shedding of STECO157 in a serotype-specific manner. In this study, we tested the ability of rabbit polyclonal sera against individual STECO103 T3SPs to block adherence of the organism to HEp-2 cells. Our results demonstrate that pooled sera against EspA, EspB, EspF, NleA and Tir significantly lowered the adherence of STECO103 relative to pre-immune sera. Likewise, pooled anti-STECO103 sera were also able to block adherence by STECO157. Vaccination of mice with STECO103 recombinant proteins induced strong IgG antibody responses against EspA, EspB, NleA and Tir but not against EspF. However, the vaccine did not affect fecal shedding of STECO103 compared to the PBS vaccinated group over the duration of the experiment. Cross reactivity studies using sera against STECO103 recombinant proteins revealed a high degree of cross reactivity with STECO26 and STECO111 proteins implying that sera against STECO103 proteins could potentially provide neutralization of attachment to epithelial cells by heterologous STEC serotypes. PMID:26451946

  17. Monoclonal antibodies produced against sporozoites of the human parasite Plasmodium malariae abolish infectivity of sporozoites of the simian parasite Plasmodium brasilianum.

    PubMed Central

    Cochrane, A H; Barnwell, J W; Collins, W E; Nussenzweig, R S

    1985-01-01

    We have used a sporozoite neutralization assay to define the biological relevance of the cross-reactivity of two monoclonal antibodies, raised against sporozoites of the human parasite Plasmodium malariae (Uganda 1/CDC), with sporozoites of the simian parasite Plasmodium brasilianum (Colombian). In vitro incubation of each of these two monoclonal antibodies with sporozoites of P. brasilianum totally abolished the infectivity of these parasites for Saimiri sciureus. Using Western blot analysis and one of the P. malariae monoclonal antibodies, we identified two sporozoite proteins characteristic of the Colombian isolate of P. brasilianum with apparent molecular weights of 56,000 and 66,000. The same monoclonal antibody identified two proteins in an extract of the Peruvian isolate of P. brasilianum with apparent molecular weights of 59,000 and 69,000. Images PMID:3899939

  18. Monoclonal antibodies produced to bean yellow mosaic virus, clover yellow vein virus, and pea mosaic virus which cross-react among the three viruses.

    PubMed

    Scott, S W; McLaughlin, M R; Ainsworth, A J

    1989-01-01

    Monoclonal antibodies prepared against individual potyviruses that infect forage legumes cross-reacted among the viruses. The reaction occurs between capsid subunits and presumably involves epitopes located in the trypsin-resistant core of the coat protein. PMID:2480762

  19. Top-down proteomic identification of Shiga toxin 2 variants from Shiga toxin-producing Escherichia coli (STEC) using MALDI-TOF-TOF-MS/MS-PSD

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) are increasingly linked to severe outbreaks of foodborne illness throughout the world, e.g. Germany and France in 2011. STEC infections can result in bloody diarrhea, hemolytic uremic syndrome, kidney failure and death. New analytical techniques are ne...

  20. Characterization of shiga toxin-producing Escherichia coli recovered from domestic animals to determine stx variants, virulence genes, and cytotoxicity in mammalian cells

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) can cause foodborne illnesses ranging from diarrhea to severe diseases such as hemorrhagic colitis (HC), and hemolytic uremic syndrome (HUS) in humans. In this study, we determined virulence genes, stx subtypes and we evaluated the cytotoxicity in mammal...

  1. Detection of Shiga toxin variants, virulence genes and the relationship to cytotoxicity in Shiga toxin-producing Escherichia coli (STEC) from domestic farm animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shiga toxin-producing Escherichia coli (STEC) can cause foodborne illnesses ranging from diarrhea to life-threating diseases such as hemorrhagic colitis, and hemolytic uremic syndrome in humans. In this study, we determined virulence genes, stx subtypes and we evaluated the cytotoxicity in STEC stra...

  2. Invasive Stratified Mucin-producing Carcinoma and Stratified Mucin-producing Intraepithelial Lesion (SMILE): 15 Cases Presenting a Spectrum of Cervical Neoplasia With Description of a Distinctive Variant of Invasive Adenocarcinoma.

    PubMed

    Lastra, Ricardo R; Park, Kay J; Schoolmeester, J Kenneth

    2016-02-01

    Stratified mucin-producing intraepithelial lesion (SMILE) is a cervical intraepithelial lesion, distinct from conventional squamous or glandular counterparts, believed to arise from embryonic cells at the transformation zone by transdifferentiation during high-risk HPV-associated carcinogenesis. It is characterized by stratified, immature epithelial cells displaying varying quantities of intracytoplasmic mucin throughout the majority of the lesional epithelium. We identified a distinct form of invasive cervical carcinoma with morphologic features identical to those in SMILE, which we have termed "invasive stratified mucin-producing carcinoma." Fifteen cases from 15 patients (mean 36 y; range, 22 to 64 y) were retrieved from the pathology archives of multiple institutions with a diagnosis of either SMILE or invasive cervical carcinoma with a description or comment about the invasive tumor's resemblance to SMILE. Seven cases had solely intraepithelial disease with a component of SMILE (mean 29 y; range, 22 to 40 y). The 8 other cases had invasive stratified mucin-producing carcinoma (mean 44; range, 34 to 64 y) in which SMILE was identified in 7. All cases of invasive stratified mucin-producing carcinoma demonstrated stratified, immature nuclei with intracytoplasmic mucin, which morphologically varied between cases from "mucin-rich" to "mucin-poor" in a similar manner to SMILE. All cases had mitotic figures and apoptotic debris, and an intralesional neutrophilic infiltrate was seen in the majority of cases. In cases of invasive carcinoma, the depth of invasion ranged from <1 to 19 mm. Follow-up information was available in 8 cases and ranged from 1 to 36 months (mean 11 mo). Three cases of invasive stratified mucin-producing carcinoma had biopsy or resection-proven metastatic carcinoma on follow-up. These 15 cases of cervical stratified mucin-producing lesions show a combination of intraepithelial and invasive growth patterns. Given that SMILE is well rooted as a

  3. Structural Characterization of New Peptide Variants Produced by Cyanobacteria from the Brazilian Atlantic Coastal Forest Using Liquid Chromatography Coupled to Quadrupole Time-of-Flight Tandem Mass Spectrometry

    PubMed Central

    Sanz, Miriam; Andreote, Ana Paula Dini; Fiore, Marli Fatima; Dörr, Felipe Augusto; Pinto, Ernani

    2015-01-01

    Cyanobacteria from underexplored and extreme habitats are attracting increasing attention in the search for new bioactive substances. However, cyanobacterial communities from tropical and subtropical regions are still largely unknown, especially with respect to metabolite production. Among the structurally diverse secondary metabolites produced by these organisms, peptides are by far the most frequently described structures. In this work, liquid chromatography/electrospray ionization coupled to high resolution quadrupole time-of-flight tandem mass spectrometry with positive ion detection was applied to study the peptide profile of a group of cyanobacteria isolated from the Southeastern Brazilian coastal forest. A total of 38 peptides belonging to three different families (anabaenopeptins, aeruginosins, and cyanopeptolins) were detected in the extracts. Of the 38 peptides, 37 were detected here for the first time. New structural features were proposed based on mass accuracy data and isotopic patterns derived from full scan and MS/MS spectra. Interestingly, of the 40 surveyed strains only nine were confirmed to be peptide producers; all of these strains belonged to the order Nostocales (three Nostoc sp., two Desmonostoc sp. and four Brasilonema sp.). PMID:26096276

  4. The germinal center antibody response in health and disease

    PubMed Central

    DeFranco, Anthony L.

    2016-01-01

    The germinal center response is the delayed but sustained phase of the antibody response that is responsible for producing high-affinity antibodies of the IgG, IgA and/or IgE isotypes. B cells in the germinal center undergo re-iterative cycles of somatic hypermutation of immunoglobulin gene variable regions, clonal expansion, and Darwinian selection for cells expressing higher-affinity antibody variants. Alternatively, selected B cells can terminally differentiate into long-lived plasma cells or into a broad diversity of mutated memory B cells; the former secrete the improved antibodies to fight an infection and to provide continuing protection from re-infection, whereas the latter may jumpstart immune responses to subsequent infections with related but distinct infecting agents. Our understanding of the molecules involved in the germinal center reaction has been informed by studies of human immunodeficiency patients with selective defects in the production of antibodies. Recent studies have begun to reveal how innate immune recognition via Toll-like receptors can enhance the magnitude and selective properties of the germinal center, leading to more effective control of infection by a subset of viruses. Just as early insights into the nature of the germinal center found application in the development of the highly successful conjugate vaccines, more recent insights may find application in the current efforts to develop new generations of vaccines, including vaccines that can induce broadly protective neutralizing antibodies against influenza virus or HIV-1. PMID:27303636

  5. Detection of Hemolysin Variants of Shiga Toxin-Producing Escherichia coli by PCR and Culture on VancomycinCefixime-Cefsulodin Blood Agar

    PubMed Central

    Lehmacher, Anselm; Meier, Heidi; Aleksic, Stojanka; Bockemühl, Jochen

    1998-01-01

    The presence of a hemolysin-encoding gene, elyA or hlyA, from Shiga toxin-producing Escherichia coli (STEC) was detected by PCR in each of 95 strains tested. PCR products of elyA from human STEC isolates of serovars frequently detected in Germany, such as O157:H−, O103:H2, O103:H−, O26:H11, and O26:H−, showed nucleotide sequences identical to previously reported ones for O157:H7 and O111:H− strains. Compared to them, four elyA amplicons derived from human isolates of rare STEC serovars showed identity of about 98% but lacked an AluI restriction site. However, the nucleotide sequence of an amplicon derived from a porcine O138:K81:H− STEC strain was identical to the corresponding region of hlyA, encoding alpha-hemolysin, from E. coli. This hlyA amplicon showed 68% identity with the nucleotide sequence of the corresponding elyA fragment. It differed from the elyA PCR product in restriction fragments generated by AluI, EcoRI, and MluI. Of the 95 representative STEC strains, 88 produced hemolysin on blood agar supplemented with vancomycin (30 mg/liter), cefixime (20 μg/liter), and cefsulodin (3 mg/liter) (BVCC). The lowest added numbers of two to six STEC CFU per g of stool or per ml of raw milk were detectable on BVCC plates after seeding of the preenrichment broth, modified tryptic soy broth (mTSB) supplemented with novobiocin (10 mg/liter), with 16 STEC strains. These strains represented the seven prevailing serovars diagnosed from German patients. However, with ground-beef samples, PCR was essential to identify the lowest added numbers of two to six STEC CFU among colonies of hemolyzing Enterobacteriaceae, such as Serratia spp. and alpha-hemolysin-producing E. coli. We conclude that preenrichment of stool and food samples in mTSB for 6 h followed by overnight culturing on BVCC is a simple method for the isolation and presumptive identification of STEC. PMID:9647814

  6. New engineered antibodies against prions

    PubMed Central

    Škrlj, Nives; Dolinar, Marko

    2014-01-01

    A number of recently developed and approved therapeutic agents based on highly specific and potent antibodies have shown the potential of antibody therapy. As the next step, antibody-based therapeutics will be bioengineered in a way that they not only bind pathogenic targets but also address other issues, including drug targeting and delivery. For antibodies that are expected to act within brain tissue, like those that are directed against the pathogenic prion protein isoform, one of the major obstacles is the blood-brain barrier which prevents efficient transfer of the antibody, even of the engineered single-chain variants. We recently demonstrated that a specific prion-specific antibody construct which was injected into the murine tail vein can be efficiently transported into brain tissue. The novelty of the work was in that the cell penetrating peptide was used as a linker connecting both specificity-determining domains of the antibody peptide, thus eliminating the need for the standard flexible linker, composed of an arrangement of three consecutive (Gly4Ser) repeats. This paves the road toward improved bioengineered antibody variants that target brain antigens. PMID:23941991

  7. Very High Plasma Concentrations of a Monoclonal Antibody against the Human Insulin Receptor Are Produced by Subcutaneous Injection in the Rhesus Monkey.

    PubMed

    Boado, Ruben J; Hui, Eric Ka-Wai; Lu, Jeff Zhiqiang; Pardridge, William M

    2016-09-01

    Brain penetration of recombinant protein drugs is possible following the re-engineering of the drug as an IgG fusion protein. The IgG domain is a monoclonal antibody (mAb) against an endogenous blood-brain barrier (BBB) receptor transporter, such as the insulin receptor. One such mAb targets the human insulin receptor (HIR) and is active in Rhesus monkeys. Prior work has measured the plasma pharmacokinetics of HIRMAb-derived fusion proteins following intravenous (IV) infusion. However, an alternative method of administration for chronic treatment of brain disease is the subcutaneous (SQ) route. The extent to which an antibody against the insulin receptor undergoes systemic distribution and clearance is unknown. Therefore, in the present study, the rate of plasma clearance of the HIRMAb is measured in Rhesus monkeys following IV or SQ administration of 3, 10, and 30 mg/kg doses of the antibody. The HIRMAb is readily absorbed into the systemic circulation following SQ injection with a 42% plasma bioavailability. The rate of plasma clearance of the antibody, 0.04-0.06 mL/min/kg, is the same following either IV or SQ administration. Owing to the slow rate of plasma clearance of the antibody, high concentrations of the HIRMAb are sustained in plasma for days after the SQ injection. The plasma concentration of the HIRMAb exceeds 0.8 mg/mL, which is 9% of the entire plasma IgG pool in the primate, after the SQ injection of the high dose, 30 mg/kg, of the antibody. In summary, the pharmacokinetics of plasma clearance of the HIRMAb are such that HIRMAb-derived fusion proteins can be developed as protein therapeutics for the brain with chronic SQ administration on a weekly or twice-weekly regimen. PMID:27513815

  8. Neutralizing Antibodies in Sera from Macaques Infected with Chimeric Simian-Human Immunodeficiency Virus Containing the Envelope Glycoproteins of either a Laboratory-Adapted Variant or a Primary Isolate of Human Immunodeficiency Virus Type 1

    PubMed Central

    Montefiori, David C.; Reimann, Keith A.; Wyand, Michael S.; Manson, Kelledy; Lewis, Mark G.; Collman, Ronald G.; Sodroski, Joseph G.; Bolognesi, Dani P.; Letvin, Norman L.

    1998-01-01

    The magnitude and breadth of neutralizing antibodies raised in response to infection with chimeric simian-human immunodeficiency virus (SHIV) in rhesus macaques were evaluated. Infection with either SHIV-HXB2, SHIV-89.6, or SHIV-89.6PD raised high-titer neutralizing antibodies to the homologous SHIV (SHIV-89.6P in the case of SHIV-89.6PD-infected animals) and significant titers of neutralizing antibodies to human immunodeficiency virus type 1 (HIV-1) strains MN and SF-2. With few exceptions, however, titers of neutralizing antibodies to heterologous SHIV were low or undetectable. The antibodies occasionally neutralized heterologous primary isolates of HIV-1; these antibodies required >40 weeks of infection to reach detectable levels. Notable was the potent neutralization of the HIV-1 89.6 primary isolate by serum samples from SHIV-89.6-infected macaques. These results demonstrate that SHIV-HXB2, SHIV-89.6, and SHIV-89.6P possess highly divergent, strain-specific neutralization epitopes. The results also provide insights into the requirements for raising neutralizing antibodies to primary isolates of HIV-1. PMID:9525675

  9. Subtype specificity of anti-HBs antibodies produced by human B-cell lines isolated from normal individuals vaccinated with recombinant hepatitis B vaccine.

    PubMed

    Shokrgozar, Mohammad Ali; Shokri, Fazel

    2002-05-22

    Hepatitis B surface antigen (HBsAg) constitutes of an immunodominant determinant common to all subtypes of hepatitis B virus (HBV) and four major subtypic determinants. Subtype specificity of the human antibody response to HBsAg has already been partially studied in vivo at serum level. No comprehensive data, however, is available at the cellular level. In this study, the methods of Epstein-Barr virus (EBV) transformation and limiting dilution assay (LDA) were used to establish a large number of B-cell lines secreting anti-HBs antibody from 34 adult individuals who were good-responders to the recombinant hepatitis B vaccine (HBsAg/adw). Specificity of 222 B-cell lines was assayed by sandwich ELISA and immunoblotting, of which 216 samples (97.3%) were identified to be anti-a, 5 samples (2.3%) as anti-d and one sample (0.4%) as anti-w. The isotype of most of the anti-HBs antibodies was IgG and belonged to the IgG1 subclass. These findings which have not already been extensively investigated at the cellular level in human confirm and extend previous circumstantial results achieved in mouse and further prove the immunodominant role of the "a" determinant of HBsAg in antibody response in human. PMID:12009275

  10. AA479 antiserum: new reagent for the serotype characterization of atypical variants of Shigella flexneri.

    PubMed

    van der Ploeg, Claudia A; Rogé, Ariel D; Bordagorria, Ximena L; de Urquiza, María T; Viñas, María R; Pichel, Mariana G; Bruno, Susana B

    2015-01-01

    Shigella flexneri is divided into 13 serotypes based on the combination of antigenic determinants present in the O-antigen. A new O-antigen modification with phosphoethanolamine has been identified. The presence of this antigenic determinant (called E1037) is recognized by monoclonal antibody MASF IV-1. Given the increasing incidence of these new variants and the difficulty in supplying the monoclonal antibody to our country, we produced a polyclonal antiserum (AA479) through immunization with a S. flexneri Xv strain. The antiserum specificity was assessed by slide agglutination against isolates from clinical cases and a culture collection representing all Shigella serotypes. The results obtained demonstrated a 100% correlation between AA479 absorbed antiserum and monoclonal antibody MASF IV-1. The availability of AA479 antiserum in every public hospital in Argentina will allow us to identify atypical S. flexneri isolates in order to strengthen Shigella surveillance in our country and to compare with global epidemiological data. PMID:25735215