ABSTRACTThe aim of a malaria transmission-blocking vaccine is to block the development of malaria parasites in the mosquito and thus prevent subsequent infection of the human host. Previous studies have demonstrated that the gametocyte/gamete surface protein Pfs230 can induce transmission-blocking immunity and have evaluatedEscherichia coli-produced Pfs230 as a transmission-blocking vaccine candidate. In this study, we used the wheat germ cell-free expression system to produce N-terminal fragments of Pfs230 and evaluated the transmission-blocking activity of antisera raised against the recombinant Pfs230 protein. The rabbit antisera reacted to the surface of cultured gametocytes and gametes of thePlasmodium falciparumNF54 line, recognized the 360-kDa form of parasite-produced Pfs230 by Western blot assay, and reduced the infectivity of NF54 parasites toAnopheles stefensimosquitoes in the presence of complement in a standard membrane feeding assay. Thus, our data demonstrate that the N-terminal pro domain of Pfs230 is sufficient to induce complement-dependent transmission-blocking activity againstP. falciparum.