Ound: Protozoan parasites from the genus Leishmania are transmitted by the bite of infected sand flies top to a wide array of diseases called leishmaniasis. Based on the species involved, it may generate a self-healing wound to a potentially lethal visceral infection. Lately, we published a seminal operate demonstrating that leishmanial exosomes (Leish Exo) were released in the lumen with the sand fly midgut and to be co-egested using the parasite through the blood meal. Leish Exo had been identified to stimulate an inflammatory response conducting to exacerbated cutaneous leishmaniasis, also it was shown that these vesicles cargo significant virulence things like GP63; According to this, our actual aim was to analyse the influence of GP63-enriched Leish Exo on the modulation of macrophage inflammatory response and its infection in mice. Methods: Working with Leish Exo isolated from Leishmania amazonensis expressing different levels of GP63 (WT, GP63low, GP63high), we tested their capacity to induce the expression of various inflammatory cytokines (e.g. TNF, IL-6) and chemokines (e.g. CXCL2). Moreover, LCMS/MS analyses of these a variety of Leish Exo preparations have been performed. Outcomes: Benefits obtained revealed that presence of GP63 differentially influences their expression in macrophages. Of interest, the presence of GP63 was confirmed and to influence the degree of Leishmania arginase becoming enriched in Leish Exo.This latter becoming vital inside the regulation of NO activity, it was thus of additional interest to test how these different Leish Exo preparations could influence the infection progression in vivo. Hence, to test this, Balb/c mice have been infected in their hind footpad with stationary L. amazonensis WT or GP63low with or without Leish Exo from every 3 groups of parasites. Summary/conclusion: Data obtained from this study are going to be further discussed in the course of the poster presentation, also as the final Zika Virus Non-Structural Protein 5 Proteins MedChemExpress conclusion in regard to the essential role played by Leishmania GP63 in Leish Exo. Funding: This work was funded by CIHR and CNPq-Brazil.B-cell population. Our group demonstrated that these cells are able to phagocytose L. (L.) amazonensis promastigotes and participate in immunity against the parasite in murine model of infection by Leishmania (Leishmania) amazonensis. On the other hand, the mechanisms underlying this protection haven’t but been uncovered. Within this study, we evaluated the release of extracellular vesicles by B-1 cells ABL1 Proteins Recombinant Proteins uninfected or infected with L. (L.) amazonensis, the part of these particles on macrophages functions and within the course of experimental infection with all the parasite. Techniques: B-1 cells had been purified from peritoneal cavities of BALB/c mice by utilizing antibodies anti-CD23 and anti-CD19 coupled with magnetic microbeads. Purified B-1 cells have been infected with L. (L.) amazonensis promastigotes for 24 h. Extracellular vesicles have been obtained from supernatant by ultracentrifugation. In vitro research have been performed with macrophages differentiated from bone marrow stimulated with EVs from B-1 cells. The experimental infection was carried out with BALB/c mice following approval on the study by the ethics and study committee of UNIFESP. Results: Nanotracking evaluation (NTA) and scanning electron microscopy showed that uninfected B-1 cells spontaneously released EVs however the parasite stimulated an increase in EVs releasing. The expression with the IL-6 and IL-10 cytokines was drastically higher in macrophages treated with EVs from infected B-1 cells.