Dados do Trabalho

Título

A potential vaccine against Leishmania infantum infection using an amastigote- specific recombinant protein, rLiHyG, associated with adjuvants

Introdução

Immunization against VL can be considered a control measure to prevent the disease, considering that specific proteins found in amastigotes of Leishmania infantum can be useful in the development of vaccines.

Objetivo (s)

The study aimed to evaluate a specific protein from Leishmania amastigotes, the recombinant protein rLiHyG, as a vaccine candidate against L. infantum infection in BALB/C mice, in addition to evaluating its performance when associated with adjuvants such as saponin or micelles polymeric.

Material e Métodos

Female BALB/C mice (n=16 per group) were immunized subcutaneously in the left hind paw pad with the recombinant protein associated with saponin (rLiHyG/Sap) or associated with polymeric micelles based on Poloxamer 407 (rLiHyG/Mic). In the other groups, only empty micelles, saponin alone or saline solution were administered. Three doses were administered at two-week intervals, and 30 days after the last vaccine dose, mice (n=8 per group; as the primary endpoint) were euthanized for immunological analyses. At the same time, the remaining animals (n=8 per group, as the secondary endpoint) were infected subcutaneously in the right hind paw with 10^7 promastigotes of L. infantum, and 45 days after infection were euthanized for immunological analysis, parasitological and toxicity assessment.

Resultados e Conclusão

The results showed that, in both outcomes, rLiHyG/Sap and rLiHyG/Mic induced higher levels of IFN-γ, IL-12, and GM-CSF in cultures of spleen cells from vaccinated animals, in addition to the increased presence of spleen antibodies. IgG2a isotype results were associated with an antileishmania Th1 immune response profile. Decreased hepatotoxicity and a positive lymphoproliferative response were also found after the challenge. Such findings were reflected in significantly lower levels of parasite load found in their spleens, livers, bone marrow, and draining lymph nodes. It is concluded that the rLiHyG protein, associated with the tested adjuvants, presented a protective response profile of a Th1 immunological profile. Therefore, it can be considered for future studies as a vaccine candidate to protect against VL.

Palavras-chave

Visceral Leishmaniasis; Vaccine; Hypothetical Protein; Adjuvants.

Agradecimentos

LIMT and LBAEL Teams; CAPES, CNPq, and FAPEMIG.