Profiling of hMPV F-specific antibodies isolated from human memory B cells

Area of Science:

• Virology
• Immunology
• Structural Biology

Background:

• Human metapneumovirus (hMPV) is a significant respiratory pathogen, closely related to respiratory syncytial virus (RSV).
• The hMPV fusion (F) glycoprotein is a key target for neutralizing antibodies due to its role in viral entry.
• Understanding antibody recognition of hMPV F is crucial for developing effective vaccines and therapeutics.

Purpose of the Study:

• To isolate and characterize a comprehensive panel of human monoclonal antibodies (mAbs) targeting the hMPV F glycoprotein.
• To delineate the epitopes and binding characteristics of these mAbs.
• To gain insights into the humoral immune response against hMPV for future therapeutic and vaccine strategies.

Main Methods:

• Isolation of 113 hMPV-F specific mAbs from memory B cells of human donors.
• Characterization of mAbs including germline gene usage, epitope mapping, neutralization potency assays, and binding specificity analysis.
• Structural and functional analysis of antibody-antigen interactions.

Main Results:

• The majority of potent neutralizing mAbs recognized epitopes on the lateral surface of the hMPV F glycoprotein, unlike RSV-F specific mAbs which often target the apex.
• Novel neutralizing epitopes distinct from those on RSV F were identified.
• Multiple binding modes for antibodies targeting specific sites (e.g., site V, site II) were observed.
• mAbs binding preferentially to the unprocessed prefusion F form exhibited lower neutralization potency.

Conclusions:

• The immune recognition of hMPV F differs significantly from RSV F, with a greater emphasis on lateral epitopes for potent neutralization.
• These findings provide a detailed map of hMPV antigenic sites and antibody binding modes.
• The study offers critical insights for the rational design of hMPV vaccines and antibody-based therapies.