Plasmodium vivax 25 kDa ookinete surface protein (Pvs25) (Pvs25)

The Plasmodium vivax 25 kDa ookinete surface protein, widely referred to as Pvs25, is a cysteine-rich protein essential for the survival and development of P. vivax parasites within the mosquito vector [11, 14]. Structurally characterized by four epidermal growth factor (EGF)-like domains, Pvs25 is expressed on the surface of zygotes and ookinetes in the mosquito midgut [11, 12]. Its primary biological function involves facilitating the transition from the ookinete to the oocyst stage, potentially through interactions with mosquito midgut proteins like calreticulin [11, 13]. As this protein is critical for parasite maturation in the vector, it has become a leading target for transmission-blocking vaccines (TBVs) [4, 15]. Vaccines targeting Pvs25, such as the recombinant protein Pvs25H or mRNA-based formulations, aim to induce host antibodies that are ingested by the mosquito alongside an infected blood meal [4, 8]. These antibodies bind to Pvs25 on the parasite surface, neutralizing its ability to invade the midgut wall and thereby halting the transmission of malaria to the next human host [10, 16]. While clinical trials have demonstrated that Pvs25 can induce functional transmission-blocking immunity, challenges remain regarding its relatively low immunogenicity and the risk of reactogenicity when paired with certain strong adjuvants [1, 10]. Furthermore, because Pvs25 is not expressed during the human phase of the malaria life cycle, natural infection does not provide immune boosting, necessitating highly potent and durable vaccine formulations [4, 11].

Other names

Pvs2525 kDa ookinete surface proteinSexual stage antigen 25 proteinP. vivax ookinete surface antigen P25Ookinete surface protein Pvs25

Transmission-blocking (TBV)