Poliovirus type 1, 2, and 3 capsid antigens (PV capsid antigens)

The poliovirus capsid is a non-enveloped, icosahedral protein shell that encapsulates the viral positive-sense RNA genome. It is composed of 60 copies each of four structural proteins—VP1, VP2, VP3, and VP4—which are generated through the proteolytic processing of the P1 precursor polyprotein [7, 12]. These proteins are organized into three distinct serotypes (types 1, 2, and 3), each characterized by specific antigenic sites that are the primary targets for neutralizing antibodies [11]. The capsid plays a critical role in the viral life cycle by protecting the genome from environmental degradation and mediating host cell entry through interaction with the poliovirus receptor (CD155) [8, 9]. Upon binding, the capsid undergoes conformational changes that lead to the externalization of VP4 and the N-terminus of VP1, forming a pore in the host membrane for genome translocation [6, 10]. Therapeutic strategies targeting these antigens include inactivated (IPV) and live-attenuated (OPV) vaccines, which provide immunity by inducing antibodies that block viral attachment [15, 17]. Additionally, small-molecule capsid inhibitors, such as pocapavir, bind to a hydrophobic pocket within the VP1 protein to stabilize the capsid and prevent the uncoating process necessary for replication [1, 4].

Other names

Poliovirus structural proteinsVP1, VP2, VP3, and VP4 proteinsP1 polyproteinPoliovirus capsid proteinsPoliovirus antigens

Vaccines induce neutralizing antibodies that bind to the capsid to prevent viral attachment and entry. Capsid inhibitors bind to a hydrophobic pocket in the capsid, stabilizing the structure and preventing the conformational changes required for viral uncoating and genome release.