Respiratory syncytial virus fusion protein site II epitope (RSV F protein site II)

The Respiratory syncytial virus fusion protein site II epitope is a conformational antigenic region on the F (fusion) glycoprotein of respiratory syncytial virus (RSV), present on both prefusion and postfusion forms.[3][4][5] The F protein is a type I transmembrane glycoprotein essential for mediating the fusion between the viral envelope and host cell plasma membrane during infection, facilitating viral entry.[3][6][7][8] Site II is a well-characterized epitope, defined as the binding site for the monoclonal antibody palivizumab, which is approved for RSV prophylaxis in high-risk infants and certain adults.[2][4][6] The F protein is a major target for neutralizing antibodies and vaccine development, with site II being accessible on both conformational states but associated with less potent neutralization relative to prefusion-specific sites (e.g., site Ø).[3][4][5] Mutations in this region can lead to resistance to monoclonal antibodies.[2][3][4] Note: Site II is not a distinct molecular entity (like a full receptor or protein) but specifically a surface-exposed linear/conformational epitope within the RSV F glycoprotein, recognized by therapeutically relevant antibodies. It is canonically used in structural vaccinology and therapeutic antibody design.[3][4][6]

Other names

RSV F protein site IIRSV fusion glycoprotein site IIRSV F antigenic site IIPalivizumab epitope

Direct neutralization of RSV by antibodies binding to site II, preventing conformational changes and membrane fusion, thereby blocking viral entry into host cells