Effect of antithymocytic serum on viral leukemia, erythroblastosis, and sarcoma in mice

The effect of heterologous antilymphocytic sera (ALS) on the growth of a number of virus-induced erythroblastoses, leukemias and sarcomas in mice has been investigated. Erythroblastosis is markedly stimulated by ALS, given either before or several days after virus inoculation. The stimulating effect of ALS administration on the outgrowth of murine sarcoma is strong if ALS is given before MSV inoculation, and weak when given no more than 24 h after the virus. Conversely, a stimulating effect of ALS on the development of leukemias was barely detectable, suggesting that immune reactions are less effective in the studied leukemia than in sarcoma and erythroblastic disease. An erythroblastic disease similar to the Friend-Rauscher virus induced splenomegaly was observed after inoculation of Moloney leukemia virus or sarcoma virus and ALS.