HLA antigens expressed on human erythroid burst forming cells.

The human major histocompatibility antigens HLA, play an important role in transplantation. To ascertain the expression of the antigens of A and B loci on the surface of human hemopoietic progenitors, the cytotoxic effect of specific anti-HLA sera was examined. Anti-HLA A2 and B5 sera were used in the present experiments. Circulating blood mononuclear cells and nucleated marrow cells, pretreated with appropriate specific anti-HLA sera and complement, formed fewer colonies from BFU-e and CFU-c in a culture medium than the controls which were treated with autologous serum. In our experiments, the HLA antisera also killed macrophages, monocytes, and T cells which carry the surface antigen. Then, the influence of macrophages, monocytes, and T cells on colony formation from BFU-e and CFU-c was examined. These results indicated that BFU-e as well as CFU-c expressed HLA antigens on their surface.