Poliovirus type 3 (Sabin) capsid neutralizing epitopes (PV3 Sabin epitopes)

The Poliovirus Sabin type 3 capsid neutralizing epitopes are specific structural regions on the surface of the type 3 attenuated poliovirus used in the Oral Poliovirus Vaccine (OPV). These epitopes are primarily located on the viral capsid proteins VP1, VP2, and VP3, and they serve as the primary targets for the host's humoral immune response (Minor et al., 1986, Nature). Binding of neutralizing antibodies to these sites prevents the virus from attaching to the host cell receptor (CD155) or interferes with the conformational changes required for viral uncoating and genome entry (Filman et al., 1989, EMBO J). In the context of the Sabin 3 strain, these epitopes are critical for the efficacy of the vaccine, but the strain is also characterized by a high rate of genetic instability (Burns et al., 2014, J Gen Virol). Mutations in or near these epitopes, particularly in the VP1 protein, can lead to the emergence of vaccine-derived polioviruses (VDPVs) that regain neurovirulence, posing a significant challenge for global polio eradication efforts (WHO, 2023). Modern vaccine design, such as the development of the novel oral poliovirus vaccine type 3 (nOPV3), focuses on stabilizing these regions to prevent reversion while maintaining the presentation of these essential neutralizing epitopes (Konopka-Aniewicz et al., 2021, Vaccine).

Other names

Antigenic site 1Antigenic site 2Antigenic site 3Antigenic site 4VP1 BC loopNeutralizing antigenic sites

Neutralization of viral infectivity by blocking attachment to the CD155 receptor or preventing viral uncoating.