DNA-based immunization with Trypanosoma cruzi complement regulatory protein elicits complement lytic antibodies and confers protection against Trypanosoma cruzi infection

A complement regulatory protein (CRP) of Trypanosoma cruzi was evaluated as a vaccine candidate in a murine model of experimental T. cruzi infection. Recombinant CRP derived from an Escherichia coli expression system and a pl asmid encoding the full-length crp structural gene under the control of a e ukaryotic promoter were used to immunize BALB/c mite. Immunization with bot h protein and DNA vaccines resulted in a Th1-type T-cell response, comparab le antibody titers, and similar immunoglobulin G isotype profiles. Only mic e immunized with the crp DNA plasmid produced antibodies capable of lysing the parasites in the presence of complement and were protected against a le thal challenge with T. cruzi trypomastigotes. These results demonstrate the superiority of DNA immunization over protein immunization with the recombi nant CRP. The work also supports the further investigation of CRP as a comp onent of a multigene, anti-T. cruzi DNA vaccine.