Immunomodulatory properties of sand fly saliva and its role on vertebrate host

The salivary glands of Phlebotomus papatasi and P. langeroni were investigated for their immunomodulatory properties on vertebrate hosts. Laboratory reared sand fly, were used for feeding on hamsters and for extraction of salivary gland. To determine the influence of the sand fly saliva homogenate (SGH) were performed ELISA using sera from injected hamsters by SGH. Frequent feeding of P. papatasi on hamsters were carried out to relate the anti-body titre with the biting rate. The mosquito Culex pipiens was allowed to feed on pre-exposed hamsters to P. papatasi bites. Antibodies correlated with the saliva of both species showed low titre and not related either to the time (after feeding and injection) or to the number of fed flies. Saliva of P. langeroni (non vector) recorded higher anti-body titre than P. papatasi. The preliminary experiment of the mosquitoes' feeding (C. pipiens) on pre-exposed hamsters on its saliva showed cross reactions between biting of mosquitoes and sand flies. More investigations are needed to study the effects of sand fly saliva on human immune responses to evaluate the fly salivary proteins as vaccines for leishmaniasis and to prevent or decrease the sand flies biting or probably mosquitoes.