T cell clones specific for IgG2a of the a allotype: direct evidence for presentation of endogenous antigen.
T cell clones specific for IgG2a of the alpha allotype have been isolated from C57BL/6J mice. Antigenic determinants recognized by these clones were localized by using a panel of hybrid IgG2b-IgG2a myeloma proteins. These experiments provide evidence for two distinct antigenic sites, one located in a segment encompassing the hinge region and most of the CH2 domain, and the other in a segment spanning the CH3 domain and the C-terminal eight residues of the CH2 domain. As judged by their failure to respond in the presence of B6.C-H-2bm12 spleen cells, all the clones recognize determinants created, in part, by the I-A beta chain. A strong proliferative response was observed in the presence of spleen cells from several H-2b strains, including C3H.SW, A.BY, D1.LP, and BALB.B. Experiments testing reactivity directed toward spleen cells from appropriate allotype-congenic mouse strains demonstrated that this response was controlled by Igh-linked genes. These results clearly indicated 1) that Igh-1a-specific T cell clones are stimulated by endogenously synthesized IgG2a, and 2) these T cells recognize shared determinants expressed on IgG2a molecules of various strains. These experiments thus provide strong evidence for presentation of self antigens under normal physiological conditions.
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Bikoff
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Birshtein
D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology*; D002999:Clone Cells / Q000145:classification / Q000276:immunology; D000939:Epitopes / Q000032:analysis / Q000235:genetics; D005260:Female; D006183:H-2 Antigens / Q000235:genetics; D007126:Immunoglobulin Allotypes / Q000032:analysis* / Q000235:genetics; D007074:Immunoglobulin G / Q000032:analysis* / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008817:Mice, Mutant Strains; D009596:Nitrophenols / Q000276:immunology; D010648:Phenylacetates; D013601:T-Lymphocytes / Q000145:classification / Q000276:immunology*
D000939:Epitopes; D006183:H-2 Antigens; D007126:Immunoglobulin Allotypes; D007074:Immunoglobulin G; D007143:Immunoglobulin Heavy Chains; D009596:Nitrophenols; D010648:Phenylacetates; C026242:4-hydroxy-5-nitrophenyl acetic acid