[No Title Available]

Abstract

Antiprolifer ative drugs (Azathioprine and M ethotrexate) were able to enhanoe a T. cruzi virulent infectkm in mioe, but failed to induce evident infectibn in animais previously vaccinateã w ith the live PF strain of the same parasite. Vinblastine (Vbl) had a similar effect w ith the virulent Y strain, but prom oted th e appearance of positive blood eultures in animais vaecinated and treated previously w ith th e drug. Negative results are obtained if the immunosupressive agent is used 15 days after the vaocine. The flagellates isolated from the vaccinateã Vbl treated mice remaineã avirulent for baby mice, after i.p. inoculation.The im m u n ity induceã by th e PF strain is probably sterile i. e. does not im ply in th e persistence of a latent infection (prem unition).