[PDGF-B immunogen preparation and the suppressive effect of anti-PDGF-B ascite antibody on the proliferation of hepG2 cells]

To observe the immunogenicity of hPDGF-B immunogens that were synthesized with the fusional expression vector pET28-Trx and to test the suppressive effect of these specific antibodies induced by both of immunogens on proliferation of human HepG2 hepatoma cells. First, we chose 2 antigenic epitopes hPDGF-BΔ103-118aa and hPDGF-BΔ152-167aa from human PDGF-B and inserted these 2 coding regions into the empty vector plasmid pET28-Trx, separately. Second, mice were immunized with purified recombinant proteins to generate polyclonal antibody. Then we intraperitoneally injected mice bearing hepatoma 22 (H22) tumor cells to prepare antibody ascites. ELISA and Western blot were used to detect the titer and the utility of the antibody, respectively. Finally, HepG2 cells were exposed to PDGF-BB protein or anti-PDGF-B ascite antibody in different dilution concentrations groups and the proliferation of HepG2 cells was quantified by CCK8 assay. As the results, we identified mice that could produce high drop of neutralizing antibodies against hPDGF-B induced by both two recombinant proteins. Two anti-PDGF-B ascite antibodies could markedly inhibit the proliferation of HepG2 cells by blocking the stimulating effect of PDGF-BB protein. Our results suggest that Trx-PDGF-B recombinant protein as immunogen provides a new method for the preparation of PDGF-B vaccine, and also a new idea for the treatment of hepatocellular carcinoma in clinical practice.