Proteção induzida pela imunização de camundongos BALB/c com proteínas ribossomais de Leishmania (LRPs) contra a infecção com L. chagasi

Abstract

Visceral leishmaniasis is a disease caused by obligate intracellular protozoa of the Leishmania (Ross, 1903) genus, which are found in countries of the Old World and in the Americas. It is a severe disease and can lead to death if not treated. The acquisition of immunity after cure of infection caused by L. major culminates in protection against re-infection by the parasite, indicating the possibility of developing a vaccine against the disease. In this study, immunization with Leishmania ribosomal proteins (LRPS), isolated from the species L. infantum, associated with the saponin adjuvant was able to induce a Th1 cellular immune response observed by the high production of IFN-, IL-12p70, GM-CSF and antibody isotype IgG2a, specific for the LRPs. It was observed that the immune response was able to induce protection in animals against L. chagasi infection, verified by the parasite burden reduction in spleen and liver of the immunized animals compared to control groups (saline and saponin). Protection was related to high production of IFN-, IL-12p70 and GM-CSF and low production of IL-4 and IL-10, and IFN- production was IL-12-dependent and mainly from lymphocytes CD4+ , CD8+ and natural killer cells. Therefore, the LRPs, as proteins highly conserved among different species of Leishmania sp., can constitute a candidate to form a pan-Leishmania vaccine.