Fusion glycoprotein of respiratory syncytial virus B (RSV F protein)

The **fusion glycoprotein of respiratory syncytial virus B** (RSV F protein) is a surface protein present as a homotrimer on the virion of respiratory syncytial virus (RSV)[2][7]. It is a class I viral fusion protein that mediates the critical step of viral entry by catalyzing the fusion of the viral envelope with the host cell membrane, following activation by host proteases[3][5]. The protein is initially synthesized as an inactive precursor (F0), which is cleaved into F1 and F2 subunits, making it fusion-competent[3]. The RSV F protein exists in a metastable prefusion conformation on the virus surface and undergoes a dramatic structural rearrangement to drive membrane fusion after a triggering event[5]. The F glycoprotein is the major target for neutralizing antibodies and is the principal antigen considered for prophylactic antibody therapies (e.g., palivizumab, nirsevimab) and subunit vaccine candidates[2][7]. It is highly conserved between RSV strains, making it especially attractive for vaccine targeting[7]. Structural studies have elucidated both prefusion and postfusion conformations; the prefusion form elicits a higher neutralizing response, driving the design of current vaccines[6][7]. Antigenic differences between RSV subgroups A and B, and between pre- and postfusion structures, affect immune recognition and vaccine efficacy[7]. Neutralization of RSV F by antibodies blocks the membrane fusion mechanism, preventing viral entry and propagation; this underlies the mechanism of action for currently approved monoclonal antibodies and vaccine-induced immunity[5][6]. Safety concerns for F-based vaccines include the need to avoid non-protective or aberrantly stabilized antigens (which could lead to enhanced disease upon infection) and the challenge of stabilizing the immunogenic prefusion conformation for use in vaccine formulations[7].

Other names

RSV fusion proteinF glycoproteinFusion (F) glycoproteinRSV FF protein

Neutralization of virus by antibodies preventing membrane fusion; Direct inhibition of conformational change required for fusion; Blocking of viral entry into host cell