Sand fly salivary proteins-parasite-skin interaction

Abstract

Abstract Leishmaniasis is a vector-borne disease transmitted by infected sand flies. During infection, sand fly salivary proteins are inoculated into the host dermis together with Leishmania parasites where proteins from the extracellular matrix are present. In this context, we hypothesize that sand fly salivary proteins interact with the parasite and with proteins from the extracellular matrix. Our preliminary findings show that proteins from sand fly salivary gland homogenate bind to the surface of promastigote forms of the parasite Leishmania infantum. Using recombinant sand fly salivary proteins we identified two major salivary proteins, LJL143 and LJL04, as the main salivary proteins binding Leishmania parasite surface. Furthermore, by a Surface Plasmon Resonance assay we tested the interaction between salivary recombinant proteins with different extracellular proteins. From all the recombinant proteins tested, only LJL04 interacts with Fibrinogen, Fibronectin, Collagen I, Multimeric VTNC and Laminin. Our plans are to confirm the salivary protein-parasite-extracellular matrix biding in vivo, firstly by exposing Balb/c mice ears to uninfected L. longipalpis bites and by detecting the presence of salivary proteins in the ear of mouse dermis post-sand fly bites. As future direction we are also planning to use L. infantum (transgenic fluorescent parasite)-infected sand flies bites to verify the possible co-localization of parasite and sand fly salivary proteins in the skin. Here, for the first time we show interaction between sand fly salivary proteins and Leishmania parasites and sand fly salivary proteins and extracellular matrix proteins.