Lacking Inefficiently Transmits to Mice.

Antibodies to AgTRIO, a mosquito salivary protein, partially reduce the initial burden in mice. We therefore silenced in mosquitoes and determined the relative contribution of AgTRIO to the ability of to transmit to mice. RNA interference-mediated silencing of resulted in a 60% reduction in expression. The decrease in expression did not alter the burden of sporozoites in mosquito salivary glands. When experimentally injected into mice, sporozoites from -silenced mosquitoes colonized the liver less effectively than sporozoites from control mosquitoes. Silencing of did not decrease the infectivity of sporozoites or influence the expression of genes associated with cell adhesion or traversal activity. AgTRIO decreased the expression of proinflammation cytokines by splenocytes Moreover, , AgTRIO decreased the expression of when coinjected with sporozoites into the skin and there was more expression at the bite site of knockdown mosquitoes than at the bite site of control mosquitoes. AgTRIO therefore influences the local environment in the vertebrate host, which facilitates sporozoite infection in mice.