Detection of H-2 antigens on 8-cell mouse embryos

H-2 antigens were detected on 80-cell mouse embryos of the b, k, and d haplotypes, but not on 8-cell embryos of the a haplotype. The technique used for detection of H-2 antigens on the embryos was a highly sensitive, automated, complement-dependent cytotoxicity assay, based on the principle that live embryos will incorporate 3H-thymidine into DNA, but embryos killed with antiserum and complement will not. The amount of H-2 present on 8-cell embryos is apparently less than that present on blastocysts. A possible function of H-2 antigens in development is proposed.