Qa-like genes defined by CTL analysis of B10.W lines.

Twelve responder-stimulator combinations of mouse B10.W strains identical at K, D, and class II loci were tested for the generation of cytolytic T lymphocytes (CTL). No primary CTL could be obtained in any of the combinations but in nine combinations CTL were generated after priming in vivo. Six of these CTL are described. They define five antigenic determinants expressed exclusively in a small group of B10.W lines. The determinants appear to be part of the same system that resembles the Qa system originally defined in classic inbred strains. This resemblance rests on the observation that in vivo priming is necessary for the generation of the CTL, and that the CTL are not restricted in their reactivity by known H-2 loci. At least some of the determinants, however, appear to be controlled by a locus (or loci) associated with the K-rather than the D-end of the H-2 complex. Furthermore, some of the CTL directed against these Qa-like determinants cross-react with a molecule controlled by the K locus.