T-cell clones recognizing MHC products.
A variety of factors may influence the reactivity of T cells with MHC products. In some cases, reactivity is dominantly influenced by one or a limited number of amino acid substitutions in the MHC molecule. Combinatorial epitopes that are dependent upon both alpha and beta chains can also be generated. MHC products, even from distinctive evolutionary backgrounds, may exhibit large regions of shared sequence, explaining patterns of clonal reactivity that would indicate the presence of shared epitopes. In other cases, epitopes may be truly cross reactive in nature, without regions of shared sequence. Indeed a limited number of clones may actually recognize either a class I or a class II MHC product. Finally, there are some patterns of clonal reactivity that cannot be explained by known structural variations. These clones either may recognize mixed class II dimers or may be influenced by peptide fragments presented in the groove of MHC gene products. This latter issue in particular requires a careful reconsideration of the process of allorecognition.
Flomenberg
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Effector Lymphocyte Biology Laboratory, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
D002999:Clone Cells; D003429:Cross Reactions; D000939:Epitopes / Q000032:analysis; D006680:HLA Antigens / Q000276:immunology*; D006801:Humans; D008285:Major Histocompatibility Complex; D013601:T-Lymphocytes / Q000276:immunology*
D000939:Epitopes; D006680:HLA Antigens