Abstract:

Objective    To screen and identify a human single-chain variable fragment(scFv) antibody against prostate specific membrane antigen(PSMA) from a human scFv antibody library. Methods    Using a synthetic PSMA peptide as the coating antigen, the antibody library was screened by five rounds of combining-eluting-amplification. The phage antibody against PSMA with high specificity was screened out from the human scFv antibody library and its binding ability to the antigen was tested by ELISA. The soluble antibody was produced by plasmids extracted from highly specific clones, whose binding ability to PSMA was further identified by Western blot and immunohistochemistry. The affinity constant of the soluble antibody was measured by non-competitive ELISA. Results    The screened phage antibody was specific for PSMA by ELISA. The soluble antibody was also specific for PSMA,  its molecular weight was about 30kD by SDS-PAGE and its affinity constant was about 5.077×106 L/mol. Conclusions    The screened scFv antibody is specific and has low immunogenicity. It can be further used in the target treatment of malignant tumors.

Key words: Prostate specific membrane antigen; Phage antibody library; Phage antibody; Affinity constant