The SF1.1.10 monoclonal antibody reacts with the mouse H-2K^d MHC class I alloantigen. MHC class I antigens are heterodimers consisting of one alpha chain (44 kDa) associated with ß2 microglobulin (11.5 kDa). The antigen is expressed by all nucleated cells at varying levels. MHC Class I molecules present endogenously synthesized antigenic peptides to CD8 T cells.

InVivoMAb anti-mouse MHC Class I (H-2Kd) (Clone: SF1.1.10 (HB159))

Trujillo, J. A., et al. (2014). “The cellular redox environment alters antigen presentation.” J Biol Chem 289(40): 27979-27991. PubMed

Cysteine-containing peptides represent an important class of T cell epitopes, yet their prevalence remains underestimated. We have established and interrogated a database of around 70,000 naturally processed MHC-bound peptides and demonstrate that cysteine-containing peptides are presented on the surface of cells in an MHC allomorph-dependent manner and comprise on average 5-10% of the immunopeptidome. A significant proportion of these peptides are oxidatively modified, most commonly through covalent linkage with the antioxidant glutathione. Unlike some of the previously reported cysteine-based modifications, this represents a true physiological alteration of cysteine residues. Furthermore, our results suggest that alterations in the cellular redox state induced by viral infection are communicated to the immune system through the presentation of S-glutathionylated viral peptides, resulting in altered T cell recognition. Our data provide a structural basis for how the glutathione modification alters recognition by virus-specific T cells. Collectively, these results suggest that oxidative stress represents a mechanism for modulating the virus-specific T cell response.

Dudek, N. L., et al. (2012). “Constitutive and inflammatory immunopeptidome of pancreatic beta-cells.” Diabetes 61(11): 3018-3025. PubMed

Type 1 diabetes is characterized by the autoimmune destruction of pancreatic beta-cells. Recognition of major histocompatibility complex (MHC)-bound peptides is critical for both the initiation and progression of disease. In this study, MHC peptide complexes were purified from NIT-1 beta-cells, interferon-gamma (IFN-gamma)-treated NIT-1 cells, splenic and thymic tissue of 12-week-old NOD mice, and peptides identified by mass spectrometry. In addition to global liquid chromatography-tandem mass spectrometry analysis, the targeted approach of multiple-reaction monitoring was used to quantitate the immunodominant K(d)-restricted T-cell epitope islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP)(2)(0)(6)(-)(2)(1)(4). We identified >2,000 MHC-bound peptides; 1,100 of these presented by beta-cells grown under normal conditions or after exposure to IFN-gamma. These include sequences from a number of known autoantigens. Quantitation of IGRP(2)(0)(6)(-)(2)(1)(4) revealed low-level presentation by K(d) (~25 complexes/cell) on NIT-1 cells after IFN-gamma treatment compared with the simultaneous presentation of the endogenously processed K(d)-restricted peptide Janus kinase-1(3)(5)(5)(-)(3)(6)(3) (~15,000 copies/cell). We have successfully sequenced peptides from NIT-1 beta-cells under basal and inflammatory conditions. We have shown the feasibility of quantitating disease-associated peptides and provide the first direct demonstration of the disparity between presentation of a known autoantigenic epitope and a common endogenously presented peptide.

Jindra, P. T., et al. (2008). “Anti-MHC class I antibody activation of proliferation and survival signaling in murine cardiac allografts.” J Immunol 180(4): 2214-2224. PubMed

Anti-MHC class I alloantibodies have been implicated in the process of acute and chronic rejection because these Abs can bind to endothelial cells and transduce signals leading to the activation of cell survival and proliferation pathways. To characterize the role of the MHC class I-signaling pathway in the pathogenesis of Ab-mediated rejection, we developed a mouse vascularized heterotopic cardiac allograft model in which B6.RAG1 KO hosts (H-2K(b)/D(b)) received a fully MHC-incompatible BALB/c (H-2K(d)/D(d)) heart transplant and were passively transfused with anti-donor MHC class I Ab. We demonstrate that cardiac allografts of mice treated with anti-MHC class I Abs show characteristic features of Ab-mediated rejection including microvascular changes accompanied by C4d deposition. Phosphoproteomic analysis of signaling molecules involved in the MHC class I cell proliferation and survival pathways were elevated in anti-class I-treated mice compared with the isotype control-treated group. Pairwise correlations, hierarchical clustering, and multidimensional scaling algorithms were used to dissect the class I-signaling pathway in vivo. Treatment with anti-H-2K(d) Ab was highly correlated with the activation of Akt and p70S6Kinase (S6K). When measuring distance as a marker of interrelatedness, multidimensional scaling analysis revealed a close association between members of the mammalian target of rapamycin pathway including mammalian target of rapamycin, S6K, and S6 ribosomal protein. These results provide the first analysis of the interrelationships between these signaling molecules in vivo that reflects our knowledge of the signaling pathway derived from in vitro experiments.

Diaz-Quinonez, A., et al. (2004). “Two Salmonella OmpC K(b)-restricted epitopes for CD8+-T-cell recognition.” Infect Immun 72(5): 3059-3062. PubMed

We report the identification of two peptides from Salmonella OmpC porin that can bind to major histocompatibility complex class I K(b) molecules and are targets of cytotoxic T lymphocytes from Salmonella-infected mice. These peptides are conserved in gram-negative bacterial porins and are the first Salmonella porin-specific epitopes described for possible CD8(+)-T-cell elimination of infected cells.

Guerrero-Plata, A., et al. (2004). “Antigen presentation by a macrophage-like cell line persistently infected with respiratory syncytial virus.” Virus Res 99(1): 95-100. PubMed

Severe infection by the human respiratory syncytial virus (RSV) early in life is associated with subsequent recurrent airway disease presumably mediated by dysregulation of the local immune response. Dysfunction of the immune response may be related to impaired macrophage functions. We have previously reported that RSV persistence in a macrophage culture (MPhiper) alters Fcgamma receptors (FcgammaR)-mediated phagocytosis and the production of pro-inflammatory cytokines. Here, we determined whether the ability of macrophages to process and present antigens and to stimulate RSV-specific CD8(+) T cells was altered in MPhiper. We also examined the level of expression of MHC class I molecules in MPhiper and the ability of these cells to present viral antigens to specific T lymphocytes. Our results showed that antigen processing and presentation were not altered by chronic RSV infection, and suggested that MPhiper were able to stimulate RSV-specific CD8(+) T lymphocytes.