Expression of serologically detectable H-2 antigens on mid-gestation mouse embryonic tissues.

Mixed haemadsorption assays using antibody-coated indicator sheep erythrocytes and mouse alloantisera revealed that major histocompatibility complex (H-2) antigens were expressed on cells of 24-72 h cultures of mid-gestation mouse embryonic skin, gut, lung, limb-bud and heart but not of embryonic gonad or kidney. The precise time of detection of H-2 antigen expression and the proportions of cells expressing these determinants depended on inbred strain, specific haplotype, tissue of origin and antiserum batch employed. In all tissues the proportion of cells expressing H-2 increased progressively from day 11-12 post-coitum onwards. The findings are discussed with respect to hypotheses concerning the possible role of major histocompatibility antigens in cellular recognition and interactions during embryogenesis.