Dados do Trabalho

Título

Recombinant endonuclease III protein from Leishmania infantum associated with Th1-type adjuvants is immunogenic and induces protection against visceral leishmaniasis

Introdução

Visceral leishmaniasis (VL) is a fatal disease when acute and untreated. Vaccination against VL should be considered as a safe and alternative measure for disease control. However, few vaccines are available for canine VL, and currently there is no approved human vaccine.

Objetivo (s)

The present study aimed to evaluate the recombinant endonuclease III protein (rENDO) combined with saponin (rENDO/Sap) or micelles (rENDO/Mic) as vaccine candidates against Leishmania infantum infection.

Material e Métodos

The recombinant protein (rENDO) was administered to BALB/c mice alone or in combination with saponin (rENDO/sap) or micelles (rENDO) as adjuvants. The control groups received saline solution, saponin, or empty micelles. The animals were subcutaneously immunized with three doses at two-week intervals, and thirty days after the last dose, they were euthanized, and their spleens and sera were collected for immunological assays. At the same time, the remaining animals were infected with L. infantum stationary promastigotes, and forty-five days post-infection, they were euthanized, and their spleens, livers, draining lymph nodes, bone marrow, and sera were collected for immunological and parasitological assays.

Resultados e Conclusão

The results showed that both vaccine compositions induced higher levels of IFN-γ, IL-12, TNF-α, and GM-CSF cytokines, as well as nitrite and IgG2a isotype antibodies, before and after challenge infection, which were related to both CD4+ and CD8+ T cell subtypes. The immunological response contributed to a significant reduction in the parasite load found in the vaccinated animals' organs. In general, mice immunized with rENDO/Mic presented a slightly higher Th1-type cellular and humoral immune response compared to those receiving rENDO/Sap. In addition, saponin caused a slight to moderate inflammatory edema in their vaccinated footpads, which was not observed when micelles were used with rENDO. In conclusion, the data suggest that rENDO could be considered a candidate to be evaluated in future studies as a vaccine to protect against VL.

Palavras-chave

visceral leishmaniasis; vaccine; recombinant protein; Th1 adjuvants

Agradecimentos

CAPES; CNPq; FAPEMIG; Programa de Pós-graduação em Ciências da Saúde: Infectologia e Medicina Tropical