Poliovirus type 2 (Sabin strain) antigen (Sabin 2)

Sabin poliovirus type 2 antigen is the attenuated viral component derived from the Sabin strain of Poliovirus type 2, historically used in the trivalent oral poliovirus vaccine (tOPV). As a member of the Picornaviridae family, the antigen is composed of a protein capsid surrounding a single-stranded RNA genome (UniProt, 2023). The primary biological role of the antigen in a medical context is to serve as an immunogen that triggers the production of systemic IgG and mucosal IgA antibodies. These antibodies neutralize the virus by blocking its interaction with the host cell receptor, CD155, thereby preventing infection of the central nervous system (PubMed, 2021). Although the wild type 2 poliovirus was declared eradicated in 2015, the Sabin 2 antigen remains a critical focus due to its propensity for genetic reversion. This reversion can lead to vaccine-associated paralytic poliomyelitis (VAPP) or the emergence of circulating vaccine-derived polioviruses (cVDPV2). To address these safety concerns, the global health community has largely replaced traditional Sabin 2 with the inactivated poliovirus vaccine (IPV) or the genetically stabilized novel oral poliovirus vaccine type 2 (nOPV2) (WHO, 2022).

Other names

Sabin 2Oral poliovirus vaccine type 2 antigenOPV2 antigenAttenuated poliovirus type 2Poliovirus type 2 (Sabin)

Induces active immunity by stimulating the production of neutralizing antibodies (IgG and IgA) that target the viral capsid proteins, preventing the virus from binding to the CD155 receptor on host cells (WHO, 2022; CDC, 2023).