Identification of distinct predominant epitopes recognized by myoglobin-specific T cells under the control of different Ir genes and characterization of representative T cell clones.
We characterized the fine specificity of antigen recognition of myoglobin-immune T cells from B10.D2, B10.GD, and B10.A(5R) mice. Polyclonal H-2d T cells show a predominant response to an epitope centering on Glu 109 and His 116. These residues localize a dominant epitope to one segment of the myoglobin surface, but probably are not the only amino acid residues involved. This response pattern maps genetically to I-Ad (or Kd) based on the B10.GD recombinant strain. A different epitope specificity was detected in B10.A(5R) T cells mapping to I-E beta b E alpha k or I-Cd, but no difference was detected between strains differing at the Igh locus. Thus, epitope specificity varied with Ia haplotype but not Igh allotype. Myoglobin-specific B10.D2 T cell lines were established, and five clones specific for the Glu 109, His 116 epitope were isolated; these were all restricted to I-Ad antigen-presenting cells. These clones represent the dominant specificity in the polyclonal T cell response to myoglobin and will be useful in characterizing the structure and function of T cell receptors for antigen and Ia. The differences in number and nature of T cell epitopes compared to B cell epitopes of myoglobin are discussed.
D000818:Animals; D002874:Chromosome Mapping; D002999:Clone Cells / Q000276:immunology; D000939:Epitopes / Q000235:genetics / Q000276:immunology*; D005260:Female; D005802:Genes, MHC Class II; D006183:H-2 Antigens / Q000235:genetics; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D009211:Myoglobin / Q000276:immunology*; D013045:Species Specificity; D013601:T-Lymphocytes / Q000276:immunology*; D014907:Whales
D000939:Epitopes; D006183:H-2 Antigens; D007143:Immunoglobulin Heavy Chains; D009211:Myoglobin