Despite Leishvaccine and Leishmune® trigger distinct immune profiles, their ability to activate phagocytes and CD8+ T-cells support their high-quality immunogenic potential against canine visceral leishmaniasis

Phenotypic features of peripheral blood leukocytes have been investigated as a pre-requisite to characterize the protective immunity attributed to both Leishvaccine and Leishmune®. Our results showed that either those vaccine were accompanied by distinct profiles on innate immune compartment. While Leishvaccine promoted early changes in phenotypic features of neutrophils and eosinophils with late involvement of monocytes, Leishmune® induced early and persistent activation of neutrophils and monocytes, without changes on eosinophil activation status. Regarding the adaptive immunity, Leishvaccine sponsored a mixed profile, associated with phenotypic changes of T and B-lymphocytes. Major phenotypic changes in CD4+ T-cells with transient activation of CD8+ T-cell, besides decreased frequency of B-cell expressing CD32 were the hallmark of Leishvaccine. In contrast, Leishmune® was associated with phenotypic changes in T-lymphocytes, particularly in CD8+ T-cells, and selective up-regulation of CD3+CD5+LowCD8+ cells. We hypothesized that this dissimilar alteration in immunological events would represent phenomenon directly related with the molecular nature of these vaccines besides the distinct adjuvants employed. However, it is important to emphasize that both immunobiologicals are able to activate phagocytes and CD8+ T-cells and therefore could be considered priority vaccines with a high-quality immunogenic potential against CVL.