Regulation of mopc 104e by T cells and growth factors induced by C. Parvum stimulation

Abstract

Corynebacterium parvum, known for its ability to retard the growth of experimental neoplasms, was examined for its effect on the growth of murine plasmacytoma MOPC 104E in vivo and in vitro. Immunostimulation with C. parvum resulted in the accelerated growth of MOPC 104E in experimental animals, as measured by the tumor IgM production. The acceleration of plasmacytoma growth was seen in all cases where C. parvum was given before or at the time of tumor transplantation. Increased proliferation of MOPC 104E was also observed when MOPC 104E was co-cultured in the presence of spleen cells from C. parvum stimulated mice as compared to the normal spleen cells. Removal of T cells by in vivo anti-thymocyte serum treatment, followed by anti-Thy 1.2 and complement in vitro, resulted in the partial loss of stimulatory activity. Furthermore, the stimulatory activity was shown to be associated with soluble mediators, which were generated by splenic adherent cells and T cells, and were, at least in part, responsible for the growth of plasmacytoma. Normal spleen cells did not generate a significant amount of soluble factor, but were able to augment MOPC 104E growth in co-culture at high spleen to tumor cell ratio.