Poliovirus type 1 capsid proteins (IPV Type 1)

The inactivated poliovirus type 1 capsid proteins are the essential antigenic components of the Salk-type inactivated poliovirus vaccine (IPV). These proteins, specifically VP1, VP2, VP3, and VP4, form the icosahedral shell of the Mahoney strain of Poliovirus Type 1 (UniProt: P03300). Inactivation via formaldehyde treatment preserves the structural integrity of the D-antigen, which is the primary epitope recognized by neutralizing antibodies (WHO, 2023). These antibodies prevent the virus from interacting with the host cell receptor, CD155, thereby neutralizing the virus before it can infect the gastrointestinal tract or spread to the central nervous system (PubMed: 11589700). Type 1 poliovirus is historically the most prevalent and paralytogenic of the three poliovirus serotypes, making its inclusion in vaccines critical for global eradication (CDC, 2021). Because the virus is inactivated, it cannot revert to a virulent form, offering a significant safety advantage over live-attenuated vaccines in the final stages of polio eradication.

Other names

Poliovirus type 1 antigenMahoney strain capsid proteinsVP1, VP2, VP3, and VP4 structural proteins (Type 1)Inactivated poliovirus vaccine type 1 component

The inactivated capsid proteins act as antigens that are processed by the host's immune system to stimulate the production of neutralizing antibodies (IgG). These antibodies specifically bind to the D-antigen epitopes on the viral surface, preventing the virus from attaching to the CD155 receptor on host cells and thereby neutralizing the infection (PubMed: 11589700).