Poliovirus type 2 capsid antigen

The **Poliovirus type 2 capsid antigen** is the main structural component of the poliovirus type 2 virion, forming an icosahedral protein shell (capsid) that contains the viral RNA genome[8][5]. The capsid is composed of four proteins (VP1–VP4) assembled from polyprotein processing; these provide structural stability and determine antigenicity[6]. This capsid mediates attachment to the human poliovirus receptor (CD155/PVR) via specific sites located in a depression or "canyon" on the capsid surface, facilitating viral entry[1][7]. Key neutralizing antigenic sites (NAg sites) on the capsid are the primary targets of the host immune response and current vaccines[1][3][7]. Variation in these sites underlies antigenic evolution, but most vaccine-derived and wild-type PV2 remain susceptible to neutralization by effective immune responses[3]. The PV2 capsid antigen is essential for polio vaccine efficacy and is used in both inactivated and live attenuated forms for immunization[5][8].

Other names

Poliovirus serotype 2 capsidPV2 capsidPoliovirus type 2 antigenPoliovirus type 2 D-antigenPV2 D-antigen

Antibodies and vaccines target the capsid antigen to induce neutralizing immunity, block receptor binding, and prevent viral entry into host cells[1][7][3] - Some antivirals or stabilization compounds may target capsid structure or assembly (experimental)