Inhibitory activity of monoclonal antibody F35.25 on the interaction between hepatocytes (HepG2 cells) and preS1-specific ligands.

The capacity of a preS1-specific monoclonal antibody (McAb) F35.25 to block the attachment of preS1-specific ligands to human hepatoma HepG2 cells was studied. In order to define more precisely the fine epitope specificity of McAb F35.25, its reaction with synthetic peptides derived from the preS1 sequence (12-53) was investigated. McAb F35.25 was found to recognize better synthetic peptide preS(21-47) from the adw 2 and ayw sequences than the synthetic peptide preS(32-53) adw 2. The shortest sequence recognized by McAb F35.25 among the peptide sequence studied was preS(32-47). The corresponding amino acid sequence (for HBV subtype adw 2) is PAFGANSNNPDWDFNP. As expected, it was found that McAb F35.25 inhibited the attachment of HepG2 cells to HBsAg-cellulose, as well as to preS(21-47)-cellulose, corresponding to two HBV subtypes adw 2 and ayw. Finally, the inhibitory effect of different peptides on the interaction of McAb F35.25 with HBsAg particles containing the preS1 sequence was also studied. The peptide preS(12-47) appeared to be the most effective inhibitor. Therefore, the McAb F35.25 is specific for the sequence preS1(X to 47), where (12 less than or equal to X less than 32). These results indicate that McAb F35.25 is probably virus-neutralizing and represents a reagent of great value to study the interaction between HBV and hepatocytes independently of d/y subtype changes.