Antibodies to liver-specific auto- and alloantigens after alloimmunization with liver tissue in the rat

LEW anti-DA liver homogenate and anti-DA liver vascularized graft sera were studied using 125I anti-immunoglobulin binding assays with liver homogenate as the target tissue. In both cases, a major component of the antibodies generated was autoantibody directed at a liver-specific antigen localized intracellularly in hepatocytes. These autoantibodies could not be detected by binding or cytotoxicity assays on lymphocyte targets. In addition, a component of the antibodies was shown to be directed against a liver-specific alloantigen located on the external and intracellular membranes of hepatocytes, and coded for by a locus not linked to the major histocompatibility complex (MHC). Alloantibodies were also demonstrated to both SD-type (RT.1A) and Ia-type (RT.1B) antigens of the MHC, with a preponderance of anti-SD antibodies.