Abstract
An in vitro assay for curative antibody present in plasma of mice cured of Trypanosoma musculi is described. The assay involves the addition of plasma to a sample of infected blood, followed by hourly monitoring of the parasite count therein. Immune plasma effected a significant reduction in parasite number, whereas normal mouse plasma did not. Heat treatment of immune plasma for 30 min at 56 degrees C abolished its ability to effect any reduction. The assay is simple, rapid, and economical and correlates well with results of all in vivo studies performed to date.