Methylazoxymethanol: effect on the immune response of rats to human serum albumin.

ABSTRACT

Inbred male F344 rats treated with 20 mg methylazoxymethanol (MAM)/kg body weight showed minimal damage to DNA in bone marrow, spleen, and thymus and no suppression of the humoral immune response to human serum albumin (HSA). At high doses of MAM (40, 60, and 80 mg/kg), damage to DNA of bone marrow, spleen, and thymus was noted. The effect on the humoral immune responses was nonuniform. Some rats responded normally by eliciting precipitating antibodies, whereas others responded by synthesizing nonprecipitating antibodies at low levels. The production of nonprecipitating antibodies may indicate a restriction of the recognition of HSA antigenic determinants in rats given injections of MAM prior to immunization. The restriction may be a consequence of suppression or elimination of certain clones of lymphocytes responsible for recognition of certain antigenic determinants. This interference in some clones of lymphocytes would result in the synthesis of antibodies against one or two antigenic sites on the HSA and the concomitant inability of the produced antibodies to form complete lattice structure with antigen.