Immunogenic and immunosuppressive components in soluble preparations from Moloney murine leukemia virus-induced tumor cells.

Soluble extracts from Moloney virus-induced leukemia cells were shown to contain immunogenic and immunosuppressive components. Immunogenic components were divided into two classes based on their ability to :(1) combine with humoral antibody to inhibit cytotoxic activity; or (2) stimulate blastogenesis in normal syngeneic lymphocytes. Immunosuppressive components were demonstrated by the inhibition of DNA synthesis in normal syngeneic lymphocytes and suppression of a mixed lymphocyte reaction. Stimulating components in many soluble preparations were completely masked by immunosuppressive components. However, all three components could be resolved by Sephadex G200 chromatography.