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Antigen Peptides (antigen + peptide)
Selected AbstractsStress for maintaining memory: HSP70 as a mobile messenger for innate and adaptive immunityEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 6 2010Taoyong Chen Abstract HSP are abundant and conserved proteins present in all cells. Upon temperature shock or other stress stimuli, HSP are synthesized intracellularly, which may protect cells from protein denaturation or from death. Although HSP are synthesized intracellularly, HSP can also be mobilized to the plasma membrane or even be released under stress conditions. Elucidating the roles of cell surface and extracellular HSP in immune regulation has attracted much attention in recent years. Extracellularly, HSP can serve a cytokine function to initiate both innate and adaptive immunity through activation of APC. HSP serves also a chaperone function and facilitates presentation of antigen peptide to T cells. Similarly, cell surface HSP may activate APC and promote antigen presentation through cell,cell contact. A study in this issue of the European Journal of Immunology demonstrates that cell surface HSP70 on DC induced by stress can upregulate membrane-associated IL-15, which in turn promotes the proliferation of CD4+CD45RA memory T cells. Moreover, a DC-CD4+ T-cell interacting circuit formed by CD40L on T cells and CD40 on DC is proposed to play a role in the maintenance of memory homeostasis. This study has widened our view of HSP in adaptive immunity as well as their classical functions such as APC activator and antigen carrier. [source] The role of the ICOS/B7RP-1 T cell costimulatory pathway in murine experimental autoimmune uveoretinitisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2006Yoshihiko Usui Abstract ICOS/B7RP-1 is a new member of the CD28/B7 family of costimulatory molecules and plays differential roles in autoimmune diseases. In this study, we examined the role of ICOS/B7RP-1 pathway in the pathogenesis of mouse experimental autoimmune uveoretinitis (EAU), an animal model of human autoimmune uveitis. ICOS expression was found on infiltrating CD4+ T cells in the region of the retina in EAU-induced mice. The anti-B7RP-1 monoclonal antibody (mAb)-treated or ICOS-deficient mice showed a substantial reduction of disease scores. Blockade of ICOS/B7RP-1 interaction during the effector phase ameliorated the disease, whereas its blockade during the induction phase exhibited no significant effect. Moreover, administration of anti-B7RP-1 mAb effectively ameliorated the disease induced by adoptive transfer of pathogenic T cells. The anti-B7RP-1 mAb treatment inhibited the expansion and/or effector function of pathogenic T cells, given that proliferative response and IFN-, production by lymph node cells were reduced upon restimulation with the antigen peptide in vitro. These results suggest that the ICOS/B7RP-1 interaction plays a critical role in the pathogenesis of uveitis. We also indicated that ICOS-mediated costimulation plays differential roles in EAU and experimental autoimmune encephalomyelitis, which is also a Th1 disease induced in the same manner as EAU. [source] Solid-phase synthesis of a dendritic peptide related to a retinoblastoma protein fragment utilizing a combined boc- and fmoc-chemistry approachJOURNAL OF PEPTIDE SCIENCE, Issue 5 2001Vittoria Cavallaro Abstract Dendritic peptides, often presented as multiple antigen peptides (MAPs), are widely used in immunological-based fields of research, although their synthesis can be extremely challenging. In this paper, a tetrameric dendritic MAP-like presentation of the retinoblastoma protein [649-654] sequence (4RB649-654) has been prepared using solid-phase peptide synthesis (SPPS) methods. During the synthesis of this dendritic molecule, numerous modifications to the synthetic protocols were examined. These modifications included the introduction of a combination Boc- and Fmoc-chemistry approach and also the use of 1,8-diazabicyclo[5.4.0]-undec-7-ene as a Fmoc-deprotection agent. The use in combination of Boc- and Fmoc-based synthetic strategies resulted in the production of the desired peptide molecule, 4RB649-654, in high purity and acceptable yields following purification by reversed phase HPLC. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd. [source] Localization of antigen-presenting cells in Helicobacter pylori -infected gastric mucosaPATHOLOGY INTERNATIONAL, Issue 4 2002Tatsuhiko Suzuki Helicobacter pylori (HP) infection is known to induce the specific immune response in the gastric mucosa. The immune response is triggered by presentation of antigen peptides on the major histocompatibility assembly of the antigen-presenting cells (APC) with the assistance of costimulatory molecules such as B7-1 (CD80) and B7-2 (CD86). Their counter-receptors or ligands on T cells are CD28 or cytotoxic lymphocyte-associated molecule-4. The aim of the present study was to clarify the localization of APC and their relation with T cells in HP-infected human gastric mucosa. Our findings suggest that the macrophages in the lamina propria may mainly act as APC in the HP-infected gastric mucosa, and the triggered immune response might be involved in the mucosal immune response in the inflamed gastric mucosa to invasive antigens related to HP organisms. [source] Characterisation of combinatorial libraries of mucin-2 antigen peptides by high-resolution mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 9 2002Emöke Windberg An epitope motif, TX1TX2T, of mucin-2 glycoprotein was identified by means of a mucin-2-specific monoclonal antibody, mAb 994, raised against a synthetic mucin-derived 15-mer peptide conjugate. For determination of the epitope sequence recognised with highest affinity by mAb 994, a combinatorial approach was applied using the portioning-mixing technique excluding Cys. Antibody binding of libraries was most profound when Gln was at the X1 position. Analytical characterisation of the TQTX2T library was conducted by amino acid analysis and matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) and electrospray ionisation Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometric methods. Control libraries were prepared by mixing 19 individual peptides corresponding to the TQTX2T sequence. Thus, mixtures of 6, 10 and 19 pentapeptides were analysed and compared with the combinatorial mixture. MALDI-TOFMS was able to detect only partially the components in the 6- and 10-member mixtures, but failed to characterise a more complex 19-member mixture. In contrast, ESI-FTICRMS resolved all mixtures of higher complexity and provided direct identification at monoisotopic resolution, such as for a peptide library containing ,isobaric' lysine and glutamine (,m,=,0.0364,Da). The results of this study suggest that ESI-FTICRMS is a powerful tool for characterisation of combinatorial peptide libraries of higher complexity. Copyright © 2002 John Wiley & Sons, Ltd. [source] Deiminated Epstein-Barr virus nuclear antigen 1 is a target of anti,citrullinated protein antibodies in rheumatoid arthritisARTHRITIS & RHEUMATISM, Issue 3 2006Federico Pratesi Objective To test the hypothesis that deimination of viral sequences containing Arg,Gly repeats could generate epitopes recognized by anti,citrullinated protein antibodies (ACPAs) that are present in rheumatoid arthritis (RA) sera. Methods Multiple antigen peptides derived from Epstein-Barr virus (EBV),encoded Epstein-Barr nuclear antigen 1 (EBNA-1) were synthesized, substituting the arginines with citrulline, and were used to screen RA sera. Anti,cyclic citrullinated peptide antibodies were purified by affinity chromatography and tested on a panel of in vitro deiminated proteins. Their ability to bind in vivo deiminated proteins was evaluated by immunoprecipitation, using EBV-infected cell lines. Results Antibodies specific for a peptide corresponding to the EBNA-135,58 sequence containing citrulline in place of arginine (viral citrullinated peptide [VCP]) were detected in 50% of RA sera and in <5% of normal and disease control sera. In addition, affinity-purified anti-VCP antibodies from RA sera reacted with filaggrin-derived citrullinated peptides, with deiminated fibrinogen, and with deiminated recombinant EBNA-1. Moreover, anti-VCP antibodies immunoprecipitated, from the lysate of calcium ionophore,stimulated lymphoblastoid cell lines, an 80-kd band that was reactive with a monoclonal anti,EBNA-1 antibody and with anti,modified citrulline antibodies. Conclusion These data indicate that ACPAs react with a viral deiminated protein and suggest that EBV infection may play a role in the induction of these RA-specific antibodies. [source] | |||||||||||||