Human Immune Response to Phlebotomus sergenti Salivary Gland Antigens in Laboratory Condition

Background: Leishmaniasis is a neglected protozoan parasitic disease, transmitted to human through sand flies bite. In animal models, previous exposure to sand fly saliva conferred substantial protection against leishmaniasis.Objectives: In the current study, Phlebotomus sergenti’s salivary gland antigens and their immune response in human were investigated.Material and Methods: The sand flies were reared at Phlebotomine insectary, and the salivary glands were dissected out. Ten human volunteers were selected, 5 individual exposed for a month and other were exposed for 8 month to P. sergenti bite. After each exposure the size of induration was measured at 24, 48 and 72 hours post bite. Specific anti-P. sergenti saliva IgG was measured by ELISA. Sand fly salivary proteins were separated by SDS PAGE and their immunrectivity showed by Western BlottingResults: The average protein amount calculated to be 0.36 μg in each pair salivary glands. Those individuals exposed to P. sergenti SGL for long time induced both antibody and DTH response, although other volunteers exposed for short time did not provoke any immune responses. The trend of antibody fluctuated during the exposure time and dropped by the end of antigen loading. Salivary gland lysate on polyacrylamid gel showed 11 to 12 major protein bands. Max and min number of antigenic bands were reported as 6 and 3 respectively.Conclusion: Our study showed that, the salivary gland components of P. sergenti provoked both cellular and humeral immune responses in human. Furthermore, there are some immunoreactive proteins inside P. sergenti’s saliva which could be subjected for further investigation as a vector-based vaccine against ACL or exposure marker