Protective immunization against visceral leishmaniasis using Leishmania sterol 24-c-methyltransferase formulated in adjuvant.

We present here the identification and characterization of Leishmania sterol 24-c-methyltransferase (SMT), as well as data on protection of mice immunized with this Ag formulated in MPL-SE. Serological evaluation revealed that SMT is recognized by VL patients. C57BL/6 mice immunized with this vaccine candidate plus MPL-SE showed Ag-specific Th1 immune responses characterized by robust production of IFN-gamma upon specific Ag re-exposure in vitro. Upon challenge with L. infantum, mice immunized with SMT plus MPL-SE showed significant lower parasite burdens in both spleens and livers compared with non-immunized mice or mice injected with adjuvant alone. The results indicate that SMT/MPL-SE can be an effective vaccine candidate for use against VL.