Construction of human Fab library and characterization of anti-HBsAg Fab fragments generated from the library

Objective To construct human antibody library with Fab,and characterize the library against hepatitis B virus surface antigen(HBsAg)generated from the constructed library.Methods Human lymphocytes were collected from 20 peripheral blood specimens of HBV-infected adult patients.The total RNA was extracted and reversely transcribed to cDNA.An anti-HBV immunized human antibody library with Fab format was constructed.Four rounds of panning were conducted against HBsAg,and phage-ELISA and DNA sequencing were used to select positive clones.Lastly,the positive clones were characterized by ELISA and functionally expressed in Escherichia coli.Results An anti-HBV immunized human Fab phage-display library consisting of 2.0×108 clones with a good diversity was successfully constructed.After 4 rounds of panning,4 clones with good reactivity to HBsAg were selected and designated as hFabHB1,hFabHB2,hFabHB,and hFabHB4,respectively.One of them,hFabHB1,was functionally expressed and its specificity was confirmed by ELISA.Conclusion The 4 clones screened from the newly-constructed antibody library could be used as candidates for prophylactic and therapeutic agent of HBV infection.