Enhancement of resistance and suppression of immunization against experimental Trypanosoma cruzi infection by Corynebacterium parvum.

Intravenous but not intraperitoneal injection of killed Corynebacterium parvum either before or after intraperitoneal infection with the highly reticulotropic Tulahuén strain of Trypanosoma cruzi produced enhanced resistance against the infection in mice. In contrast, C. parvum had no effect when the infection was caused with the predominately myotropic Y strain of T. cruzi. C. parvum given intravenously before immunization with killed culture forms of the Y strain parasite consistently diminished the protective effect against subsequent infection, which could be obtained with antigen alone.