The Immunity of Mice Cured of Trypanosome Infections

Abstract

Expts. designed to elucidate more of the immune processes of mice cured of trypanosome infections with stilbene or tryparsamide thioglycollate are reported. Immunity tests were carried out by infecting mice intraperit. with infected blood containing Trypanosoma rhcdesiense, T. equinum, T. equiperdum or T. congolense. After 2 or 3 days the animals were treated and the actual tests for immunity were performed by inoculations with parasites of either the homologous or a heterologous strain of trypanosomes. The extent which cured mice are refractory to reinoculation by homologous trypanosomes depends on the host''s ability in retaining immunity and the stability of the trypanosomes'' antigenic constitution. If this is labile, an immune mouse will readily become infected. This antigenic lability of trypanosome strains largely accounts for the difficulty of successfully immunizing men or animals against trypanosomiasis in the field. There was no cross-immunity between the strain of T. rhodesiense and a strain made resistant to suramin, but there was complete cross-immunity between the parent strain and a strain resistant to atoxyl. There was no cross-immunity as between different trypansome spp.