Inoculation of the Null Mutant Induces Long-Term Protection against Infection in BALB/c Mice.

parasites are etiological agents of cutaneous leishmaniasis in the New World. BALB/c mice are highly susceptible to challenge due to their inability to mount parasite-dependent IFN-γ-mediated responses. Here, we analyzed the capacity of a single administration of the genetically-modified attenuated line in preventing cutaneous leishmaniasis in mice challenged with virulent parasites. In previous studies, this live attenuated vaccine has demonstrated to induce long-protection against murine leishmaniasis due to Old World species. Vaccinated mice showed a reduction in the disease evolution due to challenge, namely reduction in cutaneous lesions and parasite burdens. In contrast to control animals, after the challenge, protected mice showed anti- IgG2a circulating antibodies accompanied to the induction of -driven specific IFN-γ systemic response. An analysis performed in the lymph node draining the site of infection revealed an increase of the parasite-specific IFN-ϒ production by CD4 and CD8 T cells and a decrease in the secretion of IL-10 against leishmanial antigens. Since the immunity caused by the inoculation of this live vaccine generates protection against different forms of murine leishmaniasis, we postulate as a candidate for the development of human vaccines.