Poliovirus Type 1, 2, and 3 Capsid Protein

The capsid proteins of poliovirus types 1, 2, and 3 are the structural proteins that form the outer shell (capsid) of the poliovirus particle. These proteins are critical for protecting the viral RNA genome and mediating interactions with host cells during infection. The capsid is composed of 60 copies each of VP1, VP2, VP3, and VP4. VP1 interacts directly with the host cell receptor PVR/CD155 to mediate attachment to target epithelial cells. The capsid proteins determine cellular tropism and antigenicity, which is the basis for vaccine development.

Vaccines induce neutralizing antibodies that bind to the capsid proteins and prevent viral attachment and entry into host cells.