The adjuvant effect of saponin (Quillaja bark) in the vaccine against murine cutaneous Leishmaniasis

Abstract

Experimental murine infection with Leishmania major constitutes an important model to study host immune responses to this parasite, enabling the development of new strategies for vaccination. The purpose of this study was to evaluate the adjuvant effect of saponin on the experimental infection with L. major in a murine model. Groups of female BALB/c mice were immunized with either soluble Leishmania antigen (SLA), SLA + saponin, saponin alone or control vehicle. Three days after the last boost mice were infected in the left footpad with promastigotes of L. major and followed for 10 weeks. Serum antibody levels were analyzed by ELISA and western blot and the progression of the footpad lesions was measured and compared to the uninfected side. Our results demonstrated low levels of serum antibodies, that recognized mostly antigens of 80-90 kDa in mice immunized with SLA + saponin. In this same group we observed a slower progression of the footpad lesions, which suggests that saponin plus SLA contributed to a better protection against leishmaniasis and may be used for the development of immunization schedules to this disease. UNITERMS: Leishmania major, Saponin, Antibodies, Adjuvant