부산대학교 도서관

We obtained mice deficient for major histocompatibility complex (MHC) molecules encoded by the H-2K and H-2D genes. H-2 [K.sup.b][D.sup.b] -/- mice express no detectable classical MHC class I-region associated (Ia) heavy chains, although [[Beta].sub.2]-microglobulin and the nonclassical class lb proteins examined are expressed normally. [K.sup.b][D.sup.b] -/- mice have greatly reduced numbers of mature CD8 + T cells, indicating that selection of the vast majority (> 90%) of CD8 + T cells cannot be compensated for by [[Beta].sub.2]-microglobulin-associated molecules other than classical H-2K and D locus products. In accord with the greatly reduced number of CD8 + T cells, spleen cells from [K.sup.b][D.sup.b] -/- mice do not generate cytotoxic responses in primary mixed-lymphocyte cultures against MHC-disparate (allogeneic) cells. However, in vivo priming of [K.sup.b][D.sup.b] -/- mice with allogeneic cells resulted in strong CD8 + MHC class Ia-specific allogeneic responses. Thus, a minor population of functionally competent peripheral CD8 + T cells capable of strong cytotoxic activity arises in the complete absence of classical MHC class Ia molecules. [K.sup.b][D.sup.b] -/- animals also have natural killer cells that retain their cytotoxic potential.