The adjuvant effect of Corynebacterium parvum: T-cell dependence of macrophage activation.

Splenic and peritoneal macrophages from mice treated with Corynebacterium parvum enhanced the antibody response in vitro of normal nonadherent spleen cells to SRBC, but not to DNP-POL. This enhancement was dependent on the dose and time of administration of C. parvum and could be abrogated by pretreatment with carrageenan. Macrophages from T-cell-depleted mice failed to enhance the response, but this ability was restored if the mice had been reconstituted with purified T lymphocytes. Macrophages that are activated by C. parvum are a resident nondividing population. It is postulated that activated macrophages, capable of enhancing antibody responses to T-cell-dependent antigens, arise through a cell-mediated reaction to C. parvum.