Primary in vitro cytotoxic response of NZB spleen cells to Qa-1b-associated antigenic determinants.

We have shown that cytotoxic lymphocytes generated in primary cultures of NZB spleen cells with H-2-identical BALB/c or B10.D2 stimulator cells exhibit specificity for Qa-1b-associated antigenic determinants. This unidirectional cytotoxicity constitutes the initial demonstration of a primary in vitro response to antigens of the Qa-Tla system. Such responses do not require H-2 homology between effector and target cells in the assay system. In fact, when H-2Dd homologous target cells were employed there was little, if any, evidence for development of primary H-2-restricted responses to minor locus histocompatibility antigens or viral antigens. In view of the recently defined role of Qa-1+, Ly-1,2,3+ cells as regulators of antibody responses, and of the deficiency of such cells in NZB mice, the observation of hyperreactivity for determinants of this system may be relevant to the development of autoimmunity in these animals.