Effects of Corynebacterium parvum on depressed immunological reactions in EL-4-tumor-bearing mice

Abstract

Effects of Corynebacterium parvum on the development of plaque-forming cells (PFC), cell-mediated cytotoxicity (CMC), and delayed footpad reaction (DFR) to chicken erythrocytes (CRBC) were investigated in EL-4-bearing syngeneic mice. PFC, CMC, and DFR responses after the primary immunization were suppressed in tumor-bearing mice and restored by C. parvum treatment. PFC and CMC responses in tumor-bearing mice were restored by the transfer of spleen cells of C. parvum-treated normal mice. Such powers of recovery were abrogated by the removal of glass-adherent cells but not by the removal of θ-positive or Ig-positive cells. DFR was suppressed not only in the primary but also in the secondary immunization, in contrast to PFC and CMC; the secondary responses of these types were not suppressed in tumor-bearing mice. Positive DFR was not elicited in tumor-bearing mice after adoptive transfer of sensitized lymphocytes from normal immune donors. The DFR became positive in such tumor-bearing recipients when they were treated by C. parvum. Macrophage functions in the induction phase of the immune response as accessory cells and in the expression of DFR as secondary cells appear to be suppressed in tumor-bearing mice and restored by C. parvum.