Inhibition of xenograft rejection reaction in the bug Triatoma infestans during infection with a protozoan, Trypanosoma cruzi

Autografts and allografts implanted into the body cavity of the bug Triatoma infestans provoked a poor hemocyte encapsulation, while xenografts stimulated significantly stronger reaction. This reaction of xenograft rejection, however, appeared distinctly inhibited in Trypanosoma cruzi-infected bugs. Similar effect was produced in triatomas by injecting them with the fluid from culture of the parasites. The results of these studies suggest that under natural conditions some parasites may avoid destruction and develop within the insect's body cavity following their suppression of host's defense reactions.