[Coombs-positive reactions in mice during transplantation of syngeneic tumors].

The effect of the growth of syngeneic transplantable tumors on Coombs' positive test in mice was studied. The modification of the hemagglutination test permitting one to minimize the amount of reagents used is described. Tumor transplantation induced Coombs' positive reactions in most recipients. The phenomenon could be observed in 4 murine strains and 6 tumor systems. Sometimes autoimmune reactions occurred before the emergence of palpable tumors. It is concluded that despite the influence of nonspecific factors, the principal cause of autoimmune reactivity is tumor growth. It seems that the appearance of alien "normal" histocompatibility antigens is a characteristic feature of all the tumors; besides, the host response pattern to these antigen is cross-reactive, including autoimmune component. Coombs' positive test may be one of numerous manifestations of such an autoimmune process.