Enhancement of Moloney sarcoma virus-induced tumor growth by concanavalin A

Adult mice injected intraperitoneally with concanavalin A (con-A) commencing with the onset of 6mm. Moloney sarcoma virus (MSV)-induced tumors showed a marked enhancement of tumor growth compared to untreated control mice; whereas, treatment with con-A beginning on day 0 relative to MSV inoculation had no effect. Antibody production as measured by indirect membrane fluorescence was not affected by con-A. Since in vivo administered con-A has a specific suppressive effect on T-lymphocytes it is suggested that the primary immunologic response to MSV antigens is a function of T-cells.