DNA-Based Immunization with Trypanosoma cruziComplement Regulatory Protein Elicits Complement Lytic Antibodies and Confers Protection against Trypanosoma cruziInfection

ABSTRACTA complement regulatory protein (CRP) of Trypanosoma cruziwas evaluated as a vaccine candidate in a murine model of experimental T. cruziinfection. Recombinant CRP derived from an Escherichia coliexpression system and a plasmid encoding the full-length crpstructural gene under the control of a eukaryotic promoter were used to immunize BALB/c mice. Immunization with both protein and DNA vaccines resulted in a Th1-type T-cell response, comparable antibody titers, and similar immunoglobulin G isotype profiles. Only mice immunized with the crpDNA plasmid produced antibodies capable of lysing the parasites in the presence of complement and were protected against a lethal challenge with T. cruzitrypomastigotes. These results demonstrate the superiority of DNA immunization over protein immunization with the recombinant CRP. The work also supports the further investigation of CRP as a component of a multigene, anti-T. cruziDNA vaccine.