FURTHER STUDIES OF HISTOCOMPATIBILITY LOCI IN RATS

Abstract

The minimum number of histocompatibility antigens by which two inbred rat strains, Lewis and DA, differ has been estimated to be 6 by F2-hybrid analysis. Of these, the antigens determined by the Ag-B locus are the most effective in dictating prompt homograft rejection. Furthermore, humoral antibodies, detectable as hemagglutinins, occur most frequently following homograft rejection when the donor-host disparity includes an Ag-B incompatibility. The data suggest that the short median survival time (7 days) of grafts exchanged between Lewis and DA rats is primarily a reflection of the antigenic disparity of the respective Ag-B antigens of the two strains.