AIM: To insert the constructed TGF-β1 epitope gene into the el loop of C-terminus of truncated hepatitis B core antigen to increase TGF-β1 antigenicity in its prokaryotic expression system and to identify immunity of the expressed recombinant protein in order to exploit the possibility for obtaining anti- TGF-β1 vaccine. METHODS: The TGF-β1 encoding epitope gene (the mature TGF-β1 from 78-109 amino acid residues, TGF-β132) was amplified by polymerase chain reaction from the recombinant pGEM-7z/ TGF-β132 vector. The HBcAg gene fragments (encoding HBcAg from 1-71 and 89-144 amino acid residues) were amplified from PYTA1-HBcAg vector. The recombinant vector pGEMEX-1 was used to insert HBcAg1-71, TGF-β132 and HBcAg89-144 into restrictive endonuclease enzyme and ligated with T4 ligase. The fusion gene fragments HBcAg1-71-TGF-β132-HBcAg89-144 were recloned to pET28a(+) and the DNA sequence was confirmed by the dideoxy chain termination method. The recombinant vector pET28a (+)/ CTC was transformed and expressed in E. coli BL21 (DE3) under induction of IPTG. After purification with Ni+2-NTA agarose resins, the antigenicity of purified protein was detected by ELJSA and Western blot and visualized under electron microscope. RESULTS: Enzyme digestion analysis and sequencing showed that TGF-β1 epitope gene was inserted into the el loop of C-terminus of truncated hepatitis B core antigen. SDS-PAGE analysis showed that relative molecular mass (Mr) of the expressed product by pET28a (+)/CTC was Mr 24 600.The output of the target recombinant protein was approximately 34.8% of the total bacterial protein, mainly presented in the form of inclusion body. Western blotting and ELISA demonstrated that the fusion protein could combine with anti-TGF-β1 polyclonal IgG but not with anti-HBcAg. The purity of protein was about 90 % and the protein was in the form of self-assembling particles visualized under electron microscope. This fusion protein had good anti-TGF-β1 antigenicity and could be used as anti-TGF-β1 vaccine. CONCLUSION: A recombinant prokaryotic expression system with high expression efficiency of the target TGF-β1 epitope gene was successfully established. The fusion protein is in the form of self-assembling particles and HBcAg can increase the antigenicity of TGF-β1. The expressed TGF-β1 epitope gene shows good immunogenicity and antigenicity. AIM: To insert the constructed TGF-β1 epitope gene into the el loop of C-terminus of truncated hepatitis B core antigen to increase TGF-β1 antigenicity in its prokaryotic expression system and to identify immunity of the expressed recombinant protein in order to exploit the METHODS: The TGF-β1 encoding epitope gene (the mature TGF-β1 from 78-109 amino acid residues, TGF-β132) was amplified by polymerase chain reaction from the recombinant pGEM-7z / TGF-β132 vector. The HBcAg gene fragments (encoding HBcAg from 1-71 and 89-144 amino acid residues) were amplified from PYTA1-HBcAg vector. The recombinant vector pGEMEX-1 was used to insert HBcAg1-71, TGF- β132 and HBcAg89-144 into restrictive endonuclease enzyme and ligated with T4 ligase. The fusion gene fragments HBcAg1-71-TGF-β132-HBcAg89-144 were recloned to pET28a (+) and the DNA sequence was confirmed by the dideoxy chain termination method. The recombinant vector pET28a (+) / CTC was transformed and expressed in E. coli BL21 (DE3) under induction of IPTG. After purification with Ni + 2-NTA agarose resins, the antigenicity of purified protein was detected by ELJSA and Western blot and visualized under electron microscope. RESULTS: Enzyme digestion analysis and sequencing showed that TGF-β1 epitope gene was inserted into the el loop of C-terminus of truncated hepatitis B core antigen. SDS-PAGE analysis showed that relative molecular mass (Mr) of the expressed product by pET28a (+) / CTC was Mr 24 600. The output of the target recombinant protein was approximately 34.8% of the total bacterial protein, mainly presented in the form of inclusion body. Western blotting and ELISA demonstrated that the fusion protein could combine with anti-TGF-β1 polyclonal IgG but not with anti-HBcAg. The purity of protein was about 90% and the protein was in the form of self-assembling particles visualized under electron microscope. This fusion protein had good anti-TGF-β1 antigenicit y and couldbe used as anti-TGF-β1 vaccine. CONCLUSION: A recombinant prokaryotic expression system with high expression efficiency of the target TGF-β1 epitope gene was successfully established. The fusion protein is in the form of self-assembling particles and HBcAg can increase the Antigenicity of TGF-β1. The expressed TGF-β1 epitope gene shows good immunogenicity and antigenicity.