PURE PARAFLAGELLAR ROD PROTEIN PROTECTS MICE AGAINST TRYPANOSOMA-CRUZI INFECTION

The paraflagellar rod proteins (PAR) purified from Trypanosoma cruzi e pimastigotes were shown to protect mice against an otherwise lethal ch allenge inoculum of 10(3) bloodstream-form trypomastigotes. The inject ion route used for immunization was shown to have a marked impact on t he development of protective immunity, Mice receiving subcutaneous (s. c.) injections of PAR proteins had reduced bloodstream parasitemias an d showed 100% survival following challenge, In contrast, mice immunize d via the intraperitoneal (i.p.) route developed parasitemia levels eq uivalent to those of unimmunized controls and did not survive infectio n. Western blotting (immunoblotting) demonstrated that sera from both i.p. and s.c. immunized mice reacted specifically with PAR proteins; h owever, the antibody titer of the i.p. immunized mice was approximatel y 64-fold greater than that of the s.c. immunized mice, suggesting tha t the protective response in the s.c. immunized mice is cell mediated rather than humoral.