Depression of delayed-type hypersensitivity by corynebacterium parvum, mandatory role of the spleen.

Abstract Mice pretreated with iv Corynebacterium parvum showed markedly reduced DTH reactivity to subsequently injected SRBC without concomitantly increased antibody levels. No DTH depression occurred if C. parvum was given at the same time, or after, antigen. Neither antigen sensitization at the draining lymph node level nor the subsequent loss of sensitized cells from the node was impaired by iv C. parvum pretreatment. Splenectomy before C. parvum completely abolished its depressive effect, and lymph nodes, even when directly stimulated by local injection of C. parvum , were unable to substitute for the spleen in DTH depression. Increased uptake of sensitized cells by the C. parvum stimulated spleen has been demonstrated, and the discrepancy between the spleen and lymph node performance is discussed in terms of the depression of T-cell activity by C. parvum -activated macrophages described previously.