Placental and embryo cells can induce the generation of cytotoxic lymphocytes in vitro

The fetoplacental unit possesses paternally derived histocompatibility antigens foreign to the maternal host, and, consequently, is a potentially vulnerable target for maternal immunological attack by antibodies or lymphocytic effector cells. Information is now accumulating on the alloantigenic status of the developing rodent conceptus, particularly with regard to the products of the major histocompatibility complex which appear to play a central role in immunological confrontations between allogenic tissues. The presence of H-2 complex-coded antigens has been recently shown by a number of serological methods. Little is known, however, about the ability of the fetoplacental unit to induce the generation of cytotoxic T lymphocytes, which are the main effector arm of the allogeneic graft rejection. The authors present evidence demonstrating that the mouse embryo and trophoblast, at least in the postimplantation stage, can induce the generation of cytotoxic T lymphocytes and express antigenic determinants recognized by these effector cells.