"Weak" histocompatibility antigens generate functionally "strong" humoral immunity

The kinetics and complexity of the immune responses generated by weak histocompatibility antigens on transplants of normal tissues were investigated by analyzing (1) the survival times of test skin grafts on mice that had been initially immunized with skin, liver, or kidney implants, (2) the survival times of test skin grafts on mice that had received putatively immune sera or lymphocytes harvested from an allografted host, and (3) the cytotoxic potential of these cells and sera in vitro. The data indicate that despite chronic rejection, weak antigens rapidly immunize hosts, and that the immune response includes a major humoral component that can either accelerate graft rejection or prolong graft survival.