Corpus Christi strain-induced protection to Trypanosoma cruzi infection in C3H(He) mice: effective dose, time, route, and number of vaccinations.

The study of the parameters affecting Corpus Christi strain-induced protection in C3H(He) mice against Brazil strain T. cruzi infection is reported herein. A dose of 10(7) Corpus Christi epimastigotes was found to be the most effective dose for protection. Vaccination of mice 5 days to 11 wk prior to infection was determined to be the optimal time interval for protection. The subcutaneous route for vaccination and infection provides the most effective protection to experimental animals. Multiple inoculations with Corpus Christi, whether live or freeze thawed, increased the protective effect only slightly. The Corpus Christi strain of T. cruzi has proved to be quite suitable in providing protection to highly susceptible C3H(He) mice against an infection with the virulent Brazil strain of T. cruzi.