Resistance to Trypanosoma cruzi infection in relation to the timing of IgG humoral response.

The Biozzi "high" (BH) and "low" (BL) responder mice (Selection III) differed in their susceptibility to Trypanosoma cruzi. The BH strain responded quickly to the infection, similar to the reaction of (CBA X C57B1/10)F1 mice but in contrast to the susceptible BL strain. We suggest that the IgG response mounted by the host during the prepatent period of the infection is crucial to the outcome of the infection.