ABSTRACT
Objective To evaluate the immunogenicity of group A and C meningococcal polysaccharides conjugates using different proteins as carriers. Methods Heat-labile enterotoxin B subunit (LTB)pentamer form was expressed in E. coli. The target protein was identified and purified by cation-exchange chromatography. Then biological activity of rLTB was tested using GM1-ELISA. GCMP was conjugated to rLTB with the chemical method (ADH). Furthermore, the mice were immunized with GAMp-TT/GCMP-TT conjugates and GAMP-TT/GCMP-rLTB conjugates via peritoneal. Finally the anti-polysaccharide antibody was detected. Results The GAMP-TT/GCMP-rLTB conjugate elicits remarkably higher serum antibodies in mice than GAMP-TT/GCMP-TT conjugate. Conclusion These results indicated that polysaccharide conjugates using different proteins as carriers were superior to those using only one protein as carrier.
ABSTRACT
Objective To investigate the fermentation conditions for the heat-labile enterotoxin B subunit (LTB) of genetic recombinant E.coli. Methods The effects of different kinds of media, the range of pH, the induction time, the glucose concentration, and the fed-batch on LTB level in 10-liter fermenter under the condition of cascade controlling dissolved oxygen content were analyzed. Results Under the established conditions, the cell output per liter was 40.5g, and the expression level was 30.6%. Conclusion The results indicate that the stable fermentation technology with high efficiency has been established.