Anopheles gambiae salivary gland proteins as putative targets for blockingtransmission of malaria parasites

Anopheles gambiae is the primary vector of human malaria in sub-Saharan Afr ica. Invasion of Anopheles salivary glands by Plasmodium sporozoites is a n ecessary step in the transmission of malaria and is likely to be mediated b y specific receptor-ligand interactions. We are interested in identifying p utative an A. gambiae salivary gland receptor or receptors for sporozoite i nvasion as a possible target for blocking malaria transmission. By using mo noclonal antibodies against female-specific A. gambiae salivary gland prote ins, two molecules, one of 29 kDa and one of 100 kDa, were identified and c haracterized with respect to the age and blood-feeding process of mosquitoe s. In an in vivo bioassay, the monoclonal antibody against the 100-kDa prot ein inhibited Plasmodium yoelii sporozoite invasion of salivary glands grea ter than or equal to 75%. These results show that A. gambiae salivary gland proteins are accessible to monoclonal antibodies that inhibit sporozoite i nvasion of the salivary glands and suggest alternate targets for blocking t he transmission of malaria by this most competent of malaria vectors.