Proteção contra a infecção por Leishmania (Leishmania) amazonensis por imunização de camundongos (BALB/c) com proteínas ribossomais de Leishmania sp.

Abstract

The leishmaniases are diseases caused by protozoa of the Leishmania species, and are endemic in 88 countries in the world. The acquisition of last-longing immunity after cure of leishmaniasis caused by L. major, culminating in protecting against re-infection, indicate the possibility of developing a vaccine against the disease. In this study, Leishmania ribosomal proteins (LRPs) were purified from L. infantum and L. amazonensis and used as a vaccinal immunogen associated with the saponin adjuvant in BALB/c, in order to evaluate the efficacy of protection against challenge infection with L. amazonensis. It was observed that the immunization using LRPs/saponin was able to induce a Th1 cellular response before challenge, that was primed by high production of IFN-, IL-12p70, GM-CSF and by the presence of specific-LRPs IgG2a antibodies. After challenge, it was observed a significant reduction in the parasite burden in the infected footpad, draining lymph nodes ans spleen of the immunized animals, when compared to the saline and saponin groups. The protection was correlated to an IL-12-dependent production of IFN- by CD4+ and CD8+ T cells. In mice challenged with L. amazonensis, lower levels of anti-parasite specific antibodies were detected. Thus, it can be concluded that LRPs are conserved between different Leishmania species and that LRPs plus saponin fits the requirements to compose a pan-Leishmania vaccine.