F02A9.10 Antibody

FAQs for F02A9.10 Antibody Research
(Hypothetical construct based on analogous antibody mechanisms from cited studies)

What is the structural basis for F02A9.10’s broad neutralization across viral subtypes?

F02A9.10 achieves broad neutralization through receptor-binding site (RBS) mimicry, leveraging a 23-residue heavy-chain complementarity-determining region 3 (HCDR3) to insert into the conserved viral RBS. This mimics host receptor interactions, as observed in the structurally analogous F045-092 antibody against influenza H3. Key features include:

• Aspartic acid residue at the HCDR3 tip to mimic sialic acid carboxylate .

• Hydrophobic anchor (e.g., tyrosine) inserted into a conserved Trp153/Leu194 pocket .

• Minimal HA epitope footprint (≤300 Ų), enabling tolerance to glycosylation and antigenic drift .

How can researchers validate F02A9.10’s cross-reactivity in vitro?

Use a binding affinity panel with bio-layer interferometry (BLI) or surface plasmon resonance (SPR):

Data adapted from F045-092 studies .

• Fab vs. IgG: Bivalent IgG improves avidity for low-affinity targets (e.g., H1/H13) by ~100-fold .

• Thresholds: Fab Kd <250 nM correlates with neutralization; IgG overcomes weaker Fab binding .

How to resolve contradictions between in vitro binding data and in vivo efficacy?

Case example: F02A9.10 Fab binds H1 HA weakly (Kd = 500 nM), yet IgG neutralizes H1 viruses effectively (Kd = 20 nM).

• Methodological approach:

  • Avidity modeling: Measure IgG binding kinetics on trimeric HA vs. monomeric HA .

  • In vivo testing: Administer IgG in A129 mice (IFN-deficient) at varying post-infection timepoints.

    • Example: 80% survival observed even with 5-day delayed Ab10 administration against SFTSV .

  • Epitope mapping: Use hydrogen-deuterium exchange mass spectrometry (HDX-MS) to confirm RBS engagement .

What experimental strategies identify conformational epitopes for antibodies like F02A9.10?

• Cross-linker-assisted mass spectrometry: Identify proximal residues using BS³ or DSS cross-linkers.

  • Applied to SFTSV Ab10 to map a non-linear Gn glycoprotein epitope spanning domain II and stem regions .

• Alanine scanning mutagenesis: Systematically mutate surface residues on the target antigen.

  • Example: Reduced Ab10 binding to Gn mutants (e.g., D129A, K211A) confirmed critical epitope residues .

How to design a pan-subtype vaccine using F02A9.10’s epitope?

• Epitope-focused immunogen design:

  • Stabilize the RBS in a “open” conformation using structure-guided mutations (e.g., HA1-Y98F) .

  • Multimerize immunogens on self-assembling nanoparticles (e.g., ferritin) to enhance B-cell activation .

• Validation:

  • Compare serum cross-reactivity in immunized animals against a subtype panel (H1, H2, H3, H13) .

Why does F02A9.10 fail to neutralize some strains despite high IgG affinity?

Potential mechanisms:

• Glycan shielding: N-linked glycans at HA positions 45/144 block antibody access (e.g., 2011 H3N2 Vic2011) .

• Strain-specific mutations: RBS-adjacent mutations (e.g., T135K) reduce HCDR3 insertion efficiency .

• Solution: Combine F02A9.10 with stem-targeted antibodies for synergistic neutralization .

How to assess F02A9.10’s therapeutic potential against emerging variants?

• Phylogenetic analysis: Compare target epitope conservation across >200 strains (e.g., 90% conservation in SFTSV Gn ).

• Deep mutational scanning: Generate HA/Gn mutants and test F02A9.10 binding in yeast display libraries .