Respiratory syncytial virus fusion protein (antigenic site Ø) (RSV F protein (site Ø))

The Respiratory syncytial virus (RSV) fusion (F) protein is a Class I viral fusion glycoprotein that mediates the merger of the viral envelope with the host cell plasma membrane (McLellan et al., 2013, Science). Antigenic site Ø is a highly conserved, quaternary epitope located at the apex of the F protein's metastable pre-fusion (pre-F) conformation (Ngwuta et al., 2015, Science Translational Medicine). This site is extremely sensitive to neutralization but is lost when the protein triggers and rearranges into the stable post-fusion (post-F) state. Monoclonal antibodies such as nirsevimab target site Ø with high affinity, effectively locking the protein in the pre-fusion state and preventing the mechanical action required for viral entry (Hammitt et al., 2022, NEJM). Because site Ø is the target of the most potent naturally occurring neutralizing antibodies, it is the primary focus for passive immunization strategies and structure-based vaccine design aimed at preventing RSV-related bronchiolitis and pneumonia in infants (Graham, 2017, Immunological Reviews).

Other names

RSV F protein site zeroRSV pre-fusion F protein site ØAntigenic site 0RSV pre-F site Ø

Neutralization of the virus by binding to the pre-fusion conformation of the F protein, preventing the structural transition to the post-fusion state and thereby blocking membrane fusion and viral entry into host cells (McLellan et al., 2013, Science).