Immunomodulation of human monocytes following exposure toLutzomyia intermediasaliva

Abstract Background Sand fly saliva contains potent and complex pharmacologic molecules that are able to modulate the host's hemostatic, inflammatory, and immune systems. In this study, we evaluated the effects of salivary gland sonicate (SGS) ofLutzomyia intermedia, the natural vector ofLeishmania braziliensis, on monocytes obtained from the peripheral blood mononuclear cells (PBMC) of healthy volunteers. We investigated the effects of sand fly saliva on cytokine production and surface molecule expression of LPS-stimulated human monocytes uninfected or infected withL. braziliensis. Results Pre-treatment of non-infected human monocytes withL. intermediaSGS followed by LPS-stimulation led to a significant decrease in IL-10 production accompanied by a significant increase in CD86, CD80, and HLA-DR expression. Pre-treatment with SGS followed by LPS stimulation andL. braziliensisinfection led to a significant increase in TNF-α, IL-6, and IL-8 production without significant alterations in co-stimulatory molecule expression. However, pre-treatment withL. intermediaSGS did not result in significant changes in the infection rate of human monocytes. Conclusion Our data indicate thatL. intermediasaliva is able to modulate monocyte response, and, although this modulation is dissociated from enhanced infection withL. braziliensis, it may be associated with successful parasitism