PROTECTION OF YOUNG-RATS FROM ACUTE TRYPANOSOMA-CRUZI INFECTION BY INTERFERON-GAMMA GIVEN TO THEIR MOTHERS DURING PREGNANCY

We investigated whether administration of interferon-gamma (IFN-gamma) to pregnant rats, infected or not with Trypanosoma cruzi, was likely to protect their offspring from trypanosomal infection. Upon mating wi th syngeneic sires, four groups of 70-day-old female 1 rats were subje cted to one of the following procedures: treatment with recombinant ra t (Rr)IFN-gamma 50,000 IU/rat five times/week for three weeks; infecti on with 1 x 10(6) trypomastigotes of T. cruzi at 7, 14, and 21 days af ter slating plus IFN-gamma treatment as given to the former group; the same protocol but IFN-gamma injections being replaced by injection wi th physiologic saline, Offspring were nursed by their mothers until we aning and then infected with a similar dose of T. cruzi. Pregnant rats showed no exacerbated infection but a self-resolving mild disease, re gardless of whether or not they had received IFN-gamma. Maternal infec tion with T. cruzi and/or IFN-gamma treatment did not affect gestation al outcome. Offspring born to both groups ol IFN-gamma-treated mothers were almost fully protected from acute infection, and showed higher l evels of anti-T. cruzi IgG antibodies when compared with young born to their respective IFN-gamma-untreated mothers. Measurements of IFN-gam ma serum activities indicated that ameliorated acute disease in offspr ing whose mothers were given IFN-gamma during gestation, was not assoc iated with increased levels of endogenously produced IFN-gamma.