+ +

•  

   

     Gel: 12%SDS-PAGE, Lysate: 1.25ug, 0.6ug, 0.3ug, Lane 1-3: 1.25ug, 0.6ug, 0.3ug Fusion protein of SARS-CoV-2 S2, Primary antibody: P02729(SARS-CoV-2 S2 Antibody) at dilution 1/5000, Secondary antibody: Goat anti rabbit IgG at 1/5000 dilution, Exposure time: 1 second    

  
  

SARS-CoV-2 S2 antibodies target the conserved S2 subunit of the viral spike (S) protein, which plays a critical role in membrane fusion during host cell entry. The S protein is divided into S1 (responsible for receptor binding) and S2 (mediating fusion). Unlike the hypervariable S1 subunit, particularly the receptor-binding domain (RBD), the S2 subunit is more conserved across SARS-CoV-2 variants and related coronaviruses, making it a potential target for broad-spectrum therapeutics and vaccines. S2-directed antibodies often recognize epitopes in the stalk region, fusion peptide (FP), or heptad repeat (HR) domains, which are less prone to immune evasion mutations.

Research suggests that S2 antibodies may neutralize the virus by blocking conformational changes required for membrane fusion or through Fc-mediated effector functions like antibody-dependent cellular cytotoxicity (ADCC). Although most vaccine and antibody therapies focus on S1/RBD due to potent neutralization, S2-specific antibodies have gained attention for their potential to confer cross-protection against emerging variants (e.g., Omicron) and even other sarbecoviruses. However, S2 antibodies generally exhibit weaker neutralizing potency compared to RBD-targeting ones, necessitating strategies to enhance their efficacy. Recent studies have identified several S2-specific monoclonal antibodies (e.g., COV2-3432) and explored S2-based vaccine candidates in preclinical models. Challenges remain in optimizing immunogenicity and balancing cross-reactivity with specificity. Overall, S2 antibodies represent a promising avenue for developing pan-coronavirus countermeasures.