Cytotoxicity of autosensitized lymphocytes restricted to the H-2K end of targets

Lymphocytes from rodents cultured on syngeneic fibroblasts become cytotoxic against syngeneic but not against allogeneic target cells. We investigated whether known antigens are involved in the phenomenon and the data indicate that H-2 antigens must be shared between sensitizing fibroblasts and responder lymphocytes to generate autocytotoxic cells. Furthermore, the cytotoxicity of autosensitized lymphocytes is restricted to target cells identical with respect to theK and/orI regions. F₁ hybrid lymphocytes cultured on parental fibroblasts develop cytotoxicity towards sensitizing cells. In contrast, parental lymphocytes cultured on F₁ hybrid fibroblasts will not damage the F₁ cells, although they are cytotoxic against both syngeneic and allogeneic parental cells. In addition, parental or F₁ hybrid lymphocytes cultured on parental fibroblasts are not cytotoxic against F₁ hybrid target cells. Fibroblasts heterozygous for theK end only, are also resistant to the cytotoxic action of such lymphocytes. Thus it seems that H-2 antigens, specifically theK end, antigens have a significant role in the phenomenon of autosensitization.