Effects of heterologous helminth infections on passive transfer of immunity using a mouse monoclonal IgE antibody againstSchistosoma japonicum

Abstract

Passive transfer of immunity using a mouse monoclonal IgE antibody against Schistosoma japonicum was found to be enhanced by heterologous helminth infections. BALB/c mice were infected with Toxocara canis or Nippostrongylus brasiliensis so as to induce eosinophilia prior to a challenge infection with S. japonicum. Recovery of adult schistosomes decreased in a group of mice that had been infected with T. canis and challenged with cercariae at the cutaneous site of sensitization with the IgE antibody as compared with that in mice that had been similarly treated with normal serum in the absence of T. canis infection. Histological examinations revealed a close association of polymorphonuclear cells, including eosinophils, with damaged schistosomula in the skin of T. canis-infected mice that had received the IgE antibody. An enhancement in worm reduction was also observed in mice harboring either of both nematodes when the monoclonal antibody had been injected intraperitoneally during the phase of migration of schistosomula from the skin to the lungs. In vitro studies on macrophage-mediated damage to schistosomula suggested that the enhancement in worm reduction was at least partly due to the activation of macrophages induced by the heterologous infections.