Poliovirus type 2 capsid proteins (PV2 capsid proteins)

Poliovirus type 2 (PV2) capsid proteins are the structural building blocks of the viral shell, composed of 60 copies each of the polypeptides VP1, VP2, VP3, and VP4 [1.3.1, 1.3.4]. These proteins are essential for the viral infection process, as they mediate binding to the human poliovirus receptor (CD155) and undergo conformational changes to release the viral RNA into the host cell [1.2.1, 1.3.2]. Although wild poliovirus type 2 was officially declared eradicated in 2015, vaccine-derived strains continue to cause outbreaks of paralytic poliomyelitis in regions with low immunity [1.1.3, 1.5.4]. The capsid proteins serve as the primary targets for immunization; vaccines like the inactivated poliovirus vaccine (IPV) and the novel oral poliovirus vaccine type 2 (nOPV2) present these antigens to the immune system to elicit protective neutralizing antibodies [1.6.2, 1.6.5]. Furthermore, therapeutic development has focused on capsid inhibitors such as pocapavir, which bind to a hydrophobic pocket within the VP1 protein to stabilize the capsid and block viral uncoating [1.4.1, 1.4.2]. These antigens are thus central to both the pathogenesis of the disease and the global efforts to maintain a polio-free world [1.2.4, 1.4.4].

Other names

Poliovirus type II capsid antigensPV2 structural proteinsVP1-4 of Poliovirus type 2Poliovirus type 2 capsid

Capsid inhibitors like pocapavir bind to a hydrophobic pocket within the VP1 protein, stabilizing the capsid and preventing the conformational changes required for viral uncoating and genome release [1.4.1, 1.4.2]. Vaccines (IPV and OPV) present these antigens to the immune system to elicit neutralizing antibodies that block viral attachment to the host receptor CD155 [1.6.2, 1.6.4].