Role of non‐H‐2 antigens in the cytotoxic T cell response to allogeneic H‐2

Abstract

A limiting dilution assay was used to compare the frequency of cytotoxic T lymphocyte precursors (CTL‐P) which respond to H‐2 antigens presented with additional background differences, with the frequency of CTL‐P which respond to H‐2 antigens on a self background. Individual cultures were divided and assayed for cytotoxic activity on the two targets sharing H‐2, but not the background; no cultures were seen which clearly killed one and not the other, and the same frequency of CTL‐P was measured on target cells that differed from the responder only at H‐2 and on target cells that differed also in the background, irrespective of the background of the stimulator. Thus, the assumption that allospecific cytotoxic T lymphocytes (CTL) recognize H‐2 plus minor histocompatibility antigens does not serve as an adequate explanation for the high frequency of allospecific CTL. The data also suggest that the two allelic forms of β₂‐microglobulin do not contribute to the alloantigenic determinant.