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