A 6-month-old infant develops acute bronchiolitis with wheezing and respiratory distress. Nasopharyngeal aspirate rapid antigen test is positive for respiratory syncytial virus (RSV). Which protein of RSV is the target for passive prophylaxis with palivizumab?
- A RSV G (attachment) glycoprotein
- B RSV N (nucleoprotein)
- C RSV M2-1 transcription antiterminator protein
- D RSV F (fusion) protein ✓
Explanation
Palivizumab is a humanised monoclonal IgG1 antibody targeting the RSV F (fusion) protein, which mediates viral fusion with the host cell membrane and is highly conserved between RSV subtypes A and B. By binding to an antigenic site II on the F protein, palivizumab prevents fusion and subsequent viral entry. It is used for passive prophylaxis in high-risk infants (premature infants <35 weeks, congenital heart disease, chronic lung disease of prematurity). Newer nirsevimab targets a prefusion-specific epitope (site 0) on the F protein and provides broader protection.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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