Enhancement of experimental tumors in mice by treatment with concanavalin A.

Weanling BALB/c mice given injections of 300 micrograms concanavalin A (Con A) prior to and at frequent intervals after challenge with Moloney murine sarcoma virus (M-MuSV), 3-methylcholanthrene (MCA), or TEPC-15 plasmacytoma cells showed an enhancement of tumor induction or development. With the M-MuSV and MCA systems, this enhancement was evidenced by larger tumors and, in the MCA system, by more devastating tumors. Regression of the M-MuSV-induced tumors was more prolonged in Con A-treated mice. With the TEPC-15 system, enhancement was evidenced by a more rapid mortality rate in treated animals.