H-2 compatibility requirement for virus-specific T-cell-mediated cytolysis. The H-2K structure involved is coded by a single cistron defined by H-2Kb mutant mice.

Lymphocytic choriomeningitis or vaccinia virus-immune spleen cells of H-2 mutant mice carrying a point mutation in the K region (B6 H-2ba, B6 H-2bf) cannot lyse infected wild-type H-2Kb targets and vice versa. Yet, cytotoxic T cells specific for infected H-2Kba or H-2Kbf targets are generated during virus infections as shown by cold target competition experiments. The critical structure for the apparent restriction by the K or D regions of the H-2 gene complex of cytolytic interactions between T cells and virus-infected target cells are therefore each coded, at least as shown for the K region, by a single cistron. This finding is most readily accommodated within the altered self concept (postulating that T cells are specific for virus-modified self structures) but cannot exclude the possibility of a physiological interaction mechanism being responsible for the apparent H-2 restriction of virus-specific cytotoxic T cells.