Involvement of the T cell antigen receptor and of Lyt-2 in the cytotoxic function of aged killer (AK) T cells.
Aged killer (AK) T cells are antigen-independent, IL-2-requiring variants of antigen-dependent CTL clones that have lost their original antigen specificity and have acquired, instead, specific cytotoxicity for P815 target cells. In this report we study whether AK cells use a similar or a different target cell recognition system than that of bona fide CTL. To this end, we selected from a cloned AK line variants that are partially or completely deficient in specific target recognition and/or in cytotoxic function, and analyzed these variants for expression of the T cell antigen receptor and of Lyt-2. Variants were selected from the prototype AK line (Cl 96) with specific, as well as lectin-facilitated, cytotoxicity for P815 tumor cells. Variants could be grouped into four types with increasing degrees of functional deficiency, which correlated with loss of T cell receptor and/or loss of Lyt-2. In short, loss of Lyt-2 was reflected in loss of specific target recognition, and loss of the T cell antigen receptor was reflected in loss of all cytotoxic activity. We conclude from these results that both Lyt-2 and the T cell antigen receptor are required for specific target cell recognition and the T cell antigen receptor is, in addition, required for cytotoxic function. Moreover, since AK cells express a somatically acquired specificity that differs from that of their clonal precursors, it appears that cytotoxic T cells may change their antigen receptor from one specificity to another during tissue culture.
D000818:Animals; D000950:Antigens, Ly / Q000276:immunology*; D002460:Cell Line; D002470:Cell Survival; D003602:Cytotoxicity, Immunologic; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D012515:Mast-Cell Sarcoma; D051379:Mice; D008811:Mice, Inbred DBA; D011948:Receptors, Antigen, T-Cell / Q000096:biosynthesis / Q000276:immunology*; D011994:Recombinant Proteins / Q000494:pharmacology
D000950:Antigens, Ly; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins