Malaria parasite Plasmodium vivax sexual stage antigen Pvs25 (Pvs25)

Pvs25 is a surface antigen found on the zygote and ookinete stages of *Plasmodium vivax* in the mosquito vector, playing a critical role in parasite development and transmission. It consists of four tandem EGF-like domains arranged in a triangular prism structure, stabilized by 11 disulfide bonds, and is anchored to the parasite membrane via a C-terminal GPI moiety. The protein is highly conserved among malaria parasites and forms a sheet-like coat on the parasite surface, potentially creating a protective barrier or mediating specific molecular interactions. Pvs25 is a validated target for malaria transmission-blocking vaccines: when antibodies bind to Pvs25, they inhibit parasite development inside the mosquito, preventing the spread of malaria from humans to mosquitoes and vice versa. The gene encoding Pvs25 has minimal natural sequence variation globally, favoring its candidacy in vaccine strategies. Various vaccine formats, including recombinant protein and mRNA-based, are under development or testing, with mRNA vaccines showing improved immunogenicity in recent preclinical studies. Pvs25 does not directly function as a receptor, enzyme, or signaling protein, but it is essential for parasite fitness in the mosquito vector. Therapeutic strategies targeting Pvs25 are focused on public health—reducing transmission rather than treating disease in infected individuals.

Other names

Plasmodium vivax ookinete surface protein Pvs25Ookinete surface antigen Pvs25PVX_111175 (gene ID in P. vivax Sal I reference strain)PvP25P25 (generic family, but Pvs25 is specific to P. vivax)

Antibody-mediated binding to Pvs25 blocks parasite development on mosquito gut surfaces, preventing oocyst formation and halting transmission to humans Transmission-blocking immunity does not directly treat infection, but prevents onward spread