Immunization against Trypanosoma cruzi using killed antigens and with saponin as adjuvant.

The immunization of mice with killed epimastigotes or trypomastigotes with saponin SPL as adjuvant was challenged by inoculation of blood or metacyclic trypomastigotes of T. cruzi. Immunogenic preparations were obtained by freeze-thawing of formalin treatment. The protection was effective against homologous and heterologous challenge, and lasted up to 12 weeks after the last immunization. The immunization was also effective against metacyclic trypomastigote challenge. The immunogenicity of the killed T. cruzi suspension was retained after freeze-drying.