Vaccines Comprising Sand Fly Salivary Proteins for Control of Leishmania Infection

This invention relates to the use of several peptides from the salivary glands of various sand fly species for the control of leishmania infection. Many of these peptides were shown to be effective in eliciting potent immune responses in animal models and are excellent candidates for the development of vaccines against the disease. A vaccine comprising one of the peptides was used to protect mice challenged with parasites and salivary gland homogenates. A DNA vaccine containing the cDNA for this same peptide also provided protection that lasted at least 3 months after immunization and produced both intense humoral and delayed-type hypersensitivity reactions. Other experiments have shown that B cell-deficient mice immunized with the plasmid vaccine also successfully controlled leishmania infection. Current in-vivo studies continue to explore the use of these sand fly salivary peptides for use as animal vaccines.

Leishmania parasites are transmitted to their vertebrate hosts by infected sand fly bites. Sand fly saliva helps to enhance infection but immunity to the saliva protects against the infection, allowing the possibility of vaccine development. A number of major salivary proteins from sand fly species such as Lutzomyia longipalpis, Phlebotomus ariasi, and Phlebotomus perniciosus are claimed in the invention.

Leishmania infection affects as many as 12 million people worldwide, with 1.5-2 million new cases each year. Control of this disease will be a major milestone for public health efforts in endemic areas of the world. The current invention provides a potential means to achieve widespread vaccination that may lead to significantly control of the disease in areas such as South America, South Asia, and the Mediterranean where it is still a significant health problem. An effective veterinary vaccine will be of benefit to veterinary medicine and may pave the way for human vaccines against Leishmaniasis. The vaccination of animals may also have a positive impact on the epidemiology of the disease by reducing the number of animal reservoirs and the possibility of human infection.