Trypanocidal activity of blood and tissue fluid from normal and infected rabbits treated with curative drugs.

A new technique for determining the trypanocidal activity of body fluids has been devised, using very small quantities in the wells of plastic microtest plates. The activities of blood and tissue fluid of rabbits have been measured after the infection of melarsoprol, suramin, diminazene aceturate and isometamidium chloride. Activity against Trypanosoma (Trypanozoon) brucei persisted in body fluids for a shorter time in treated normal rabbits than in treated rabbits infected with the trypanosome. The difference was caused by the participation of the immune response of the infected animals. The new technique was sensitive enough to detect these interactions of chemotherapy and immunology and should be of use in the study of new trypanocidal compounds.