rpsF Antibody

Antigenic Target: RSV F-Protein Conformations

The RSV F-protein exists in two conformations:

• Prefusion (preF): A lollipop-shaped structure present on the virion surface before membrane fusion.

• Postfusion (postF): A crutch-shaped structure formed after membrane fusion, which is energetically stable but less immunogenic .

Key antigenic sites:

Antibodies targeting preF-exclusive sites (Ø, V) exhibit superior neutralization compared to those recognizing shared epitopes .

Antibody Repertoire and Genetic Features

Analyses of memory B cells from naturally infected adults reveal:

• Cross-binder antibodies:

  • 65–80% of neutralizing antibodies (nAbs) recognize both preF and postF conformations.

  • Utilize diverse IGHV/IGKV gene rearrangements .

• preF-specific antibodies:

  • 20–35% of nAbs exclusively bind preF.

  • Dominated by IGHV1 germline-derived clonotypes (e.g., IGHV1-69, IGHV1-18) .

  • Target a vulnerable epitope between Site Ø, Site II, and Site V .

Functional characteristics:

Clinical and Vaccine Implications

Vaccine development:

• PreF-based vaccines (e.g., RSVpreF) induce 8–12x higher neutralizing titers than postF vaccines .

• Phase 1/2 trials demonstrate persistent antibody titers for ≥12 months post-vaccination .

Monoclonal antibodies (mAbs):

• PreF-specific mAbs (e.g., D25, AM22) show picomolar neutralization potency .

• Structural studies guide epitope-focused vaccine design to mimic preF-specific B-cell responses .

Research Findings and Data Synthesis

Table 1: Antibody persistence in RSVpreF vaccine trials

Key observations:

• PreF antibodies account for >90% of serum neutralization activity in convalescent individuals .

• Fc-mediated effector functions (ADCC, ADCP) enhance viral clearance but may exacerbate inflammation in some populations .

Challenges and Future Directions

• Antigenic drift: PreF antibodies exert selective pressure, necessitating epitope stability monitoring .

• Adjuvant strategies: Aluminum hydroxide adjuvants improve antibody longevity without altering epitope specificity .

• Dual targeting: Combining preF-specific and cross-binder antibodies may broaden protection against RSV subtypes .