ABSTRACT
Objective:To prepare Streptococcus pneumonia type 3 capsular polysaccharide conjugate vaccine.Methods:Strep-tococcus pneumonia type 3 capsular polysaccharide was covalently linked to protein CRM197 and its immunogenicity was evaluated in infant mice.Results:Through the preliminary research, we found that the polysaccharide was treated with 0.2 mol/L acetic acid at 85℃ for 1 h,activation grade reached to 10.0,and the radio of polysaccharide and protein was 20∶10,could induce infant mice to produce the high titers of antibodies.Conclusion:This result shows that conjugate vaccine prepared under this condition retained intact antigenicity.It is applicable to prepare Streptococcus pneumonia type 3 capsular polysaccharide conjugate vaccine by the process condi-tions.
ABSTRACT
In order to establish an efficient and low-cost production procedure of recombinant glycerol kinase (r-GK), we expressed the r-GK gene at high level in E. coli by induction with lactose on a large-scale fermentation of 300L. The results showed that the biomass concentration reached OD600 of 42 and the expression of r-GK in E. coli accounted for about 30% of total soluble protein. The cell-free extract was processed by selective thermo-denaturation and then purified with Ni sepharose FF column chromatography. Finally, highly purified r-GK was obtained and its purity reached 97% by using analysis on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), polyacrylamide gel electrophoresis (PAGE) and gradient polyacrylamide gel electrophoresis (Gradient PAGE). Further identification study showed that the molecular weight of r-GK was 120kDa with two subunit of 58kDa. Contaminants of NADH oxidase and catalase were not detected in the sample pool of r-GK. The purified r-GK was able to retain about 85% of its initial activity at 4 degrees C for 30 days. After lyophilized, it can retain 93% of its initial activity at 4 degrees C for one year.