Vaccine Research (Nov 2015)
Sand fly saliva: toward a vaccine against leishmaniases
Abstract
Leishmaniases are a group of sand fly-borne diseases caused by protozoan parasites from species of Leishmania genus. These diseases are reported in about 100 countries with a prevalence of 12 million people infected and incidence of 2 million people per year, putting approximately 350 million people at risk of the infections. Leishmaniases are endemic and are considered as important public health problems in many provinces of Iran. The infection is transmitted through the bite of phlebotomine sand flies. The sand fly salivates while biting the vertebrate host. The saliva of phlebotomines consists of different molecules that are necessary for a sand fly to successfully take a blood meal. Additionally, previous exposures to sand fly saliva indirectly affect the establishment of Leishmania in the vertebrate host. Moreover, mice previously exposed to the saliva by injection or by uninfected sand fly bites have shown both humoral and cellular immune responses against the salivary antigens that protects them against Leishmania infection. Importantly, the immunization of mice with defined molecules from the saliva of the vector species has also conferred a strong protection against Leishmania infection. This suggests that such salivary components may be considered as candidates for a cocktail vaccine against leishmaniases. The current article briefly explains the potential of salivary components of sand fly vectors as immunological items to prevent leishmaniasis. So far, there is no efficient vaccine against these infections and efforts are required to be focused on developing effective and applicable vaccines against leishmaniases.