Salivary gland material from the sand fly Lutzomyia longipalpis has an inhibitory effect on macrophage function in vitro.

Previous work from our laboratory demonstrated that the infectivity of the protozoan parasite Leishmania major was enhanced in mice if the infecting inoculum contained salivary gland lysates from the sand fly vector Lutzomyia longipalpis. The present study was designed to address the hypothesis that sand fly salivary gland material may function by inhibiting the host immune response. Results indicated that sand fly saliva inhibited the ability of macrophages to present leishmanial antigens to parasite-specific T cells.