Plasmodium falciparum circumsporozoite protein (PfCSP) (PfCSP)

The Plasmodium falciparum circumsporozoite protein (PfCSP) is the primary surface antigen of the malaria sporozoite, the stage of the parasite transmitted by mosquitoes to humans [9, 11]. PfCSP forms a dense coat on the sporozoite and is essential for parasite development in the mosquito and the subsequent invasion of human hepatocytes [11, 15]. It functions as an adhesion molecule by binding to heparan sulfate proteoglycans on the liver cell surface, triggering the invasion process [1, 15]. This protein is the target of the World Health Organization-recommended vaccines RTS,S/AS01 and R21/Matrix-M, as well as several monoclonal antibodies in clinical development [9, 17]. Vaccine-induced antibodies work by neutralizing sporozoites and blocking their entry into the liver, thereby preventing the symptomatic blood-stage of the disease [6, 10]. However, the high levels of sequence variation and the rapid decline of antibody titers present significant challenges for long-term therapeutic efficacy [4, 17].

Other names

CSPPfCSPCircumsporozoite surface proteinMajor sporozoite surface protein

Neutralization of sporozoite infectivity by blocking hepatocyte binding and invasion; promotion of opsonic phagocytosis and cellular killing [6, 10, 14].