Relationships between H-2 and viral antigens in murine oncornavirus-induced tumours

Cytolytic T lymphocytes (CTL) from murine sarcoma virus (MSV) or Friend leukaemia virus (FLV) inoculated mice lyse syngeneic much more efficiently than allogeneic FMRGi+ lymphoma cells. By comparing the cytolysis of various H-2 different 51Cr lymphomas by CTL from several inbred and congenic lines differing at H-2, and by competition experiments using unlabelled cells, one can demonstrate that this phenomenon is due to an H-2 barrier. H-2b/H-2d hybrid-anti-MSV-CTL immunized by H-2b, H-2d or H-2b/H-2d tumours lyse only FMRGi+ lymphomas of the same H-2, and their activity for a given target is inhibited only by H-2-identical competitive cells. H-2 antigens are therefore directly involved in the interaction between tumour cells and immune CTL which probably react with an 'H-2 modified' antigen of the tumour cells surface. The use of CTL from intra-H-2 recombinant lines shows that H-2D and probably H-2K molecules are involved, but vary according to the tumour cells. A possible role of the I region is discussed as well as the implications of these results in immunosurveillance against viral neoplasia.