Antibodies presumably cross-reacting with mouse retrovirus type B and C in the sera of both leukemia-lymphoma and mammary cancer patients.

In the mouse, retrovirus B and C are causal agents of mammary cancer and leukemia, respectively. In previous work it was demonstrated that sera of leukemia-lymphoma patients possess antibodies which react with antigenic determinants of Type C virus present on AKR-lymphoma and AKR-thymus targets. The object of this paper was to determine whether these antibodies also reacted with Type B viral antigens present on a virus-induced BALB-mammary carcinoma; at the same time a comparative study was carried out with sera of breast cancer patients. A total of 325 sera were obtained from 277 leukemia-lymphoma cases under protocol treatment: 232 acute lymphoid leukemia, 23 acute myeloid leukemia, 15 chronic myeloid leukemia and 55 Hodgkin lymphoma sera. A total of 240 sera were obtained from breast cancer patients at the time of diagnosis and 196 sera from normal blood donors served as controls. Using indirect immunofluorescence with labeled anti-human IgG and the murine targets, antibodies were encountered in a high percentage of cancer cases and were consistently absent in normal sera. The results confirm the presence of antibodies reacting with murine Type C virus in leukemia-lymphoma cases and indicate the presence of antibodies reacting to both Type B and C retroviruses in the sera of breast cancer patients.