ABSTRACT
<p><b>OBJECTIVE</b>To construct, express and purify human fusion proteins composed of a single-chain antibody fragment scFv that recognizes the prostate specific membrane antigen (PSMA) protein, Fdt, HA2 and tp, and to analyze the binding activity of the expressed fusion proteins.</p><p><b>METHODS</b>The fusion protein genes scFv, scFv-tp, and scFv-Fdt-HA2-tp were amplified by PCR, and the genes obtained were then cloned into the expression vector pET28 and expressed in E. coli BL21. The expressed products were identified by SDS-PAGE and Western blot and purified with Ni(2+)-NTA chelating agarose. The antigen-binding activity of the fusion proteins was determined by ELISA.</p><p><b>RESULTS</b>The human anti-PSMA fusion gene was successfully constructed and expressed in M15 as the inclusion body after induced with IPTG. All the target proteins expressed could bind the PSMA antigen.</p><p><b>CONCLUSION</b>Fusion proteins can specifically bind the PSMA antigen. This finding contributes to the study of the targeted delivery of siRNA.</p>