Many
vaccine candidates against
visceral leishmaniasis (VL) have been proposed; however, to date, none of them have been efficacious for the human or
canine disease. On this basis, the design of
leishmaniasis vaccines has been constantly changing, and the use of approaches to select specific
epitopes seems to be crucial in this scenario. The ability to predict T cell-specific
epitopes makes immunoinformatics an even more necessary approach, as in VL an efficient immune response against the parasite is triggered by T lymphocytes in response to Leishmania spp. immunogenic
antigens. Moreover, the success of
vaccines depends on the capacity to generate long-lasting memory and polyfunctional cells that are able to eliminate the parasite. In this sense, our study used a combination of different approaches to develop potential chimera candidate
vaccines against VL. The first point was to identify the most immunogenic
epitopes of Leishmania infantum
proteins and construct chimeras composed of Major histocompatibility complex (MHC) class I and II
epitopes. For this, we used immunoinformatics features. Following this, we validated these chimeras in a murine model in a thorough memory study and multifunctionality of T cells that contribute to a better elucidation of the immunological protective mechanisms of polyepitope
vaccines (chimera A and B) using multicolor flow cytometry. Our results showed that in silico-designed chimeras can elicit polyfunctional T cells producing T helper (Th)1
cytokines, a strong immune response against Leishmania
antigen, and the generation of central and effector memory T cells in the spleen cells of vaccinated animals that was able to reduce the parasite burden in this organ. These findings contribute two potential candidate
vaccines against VL that can be used in further studies, and help in this complex field of
vaccine development against this challenging parasite.