The Research Of Type 3 Pneumococcus Capsular Polysaccharide Conjugate Vaccine And Its Immunogenicity

The morbidity and mortality rates of disease caused by Streptococcus pneumoniae are extremely high all over the world, especially in the elder and children. The decreased antibodies cannot reach the level of primary immunity response in case that the capsular polysaccharide is TI-Ag, that it cannot induce immune cell. The effect of produced TD-Ag have enhanced when Streptococcus pneumoniae were united with protein, then the antibodys for the elder and children produced. So the research of streptococcus pneumoniae conjugate vaccine had a great significance.The research discussed mainly the process of type 3 streptococcus pneumoniae capsular polysaccharide unite with protein. The conjugate vaccine were prepared through the hydrolysis pretreament of capsular polysaccharide, molecular sieving, aldehyde oxidized, ultra-filtration, covalently bonded with CRM197 protein, SDS-PAGE and AKTA FPLC system. Then its immunogenicity tested by animal immune experiment.The research studied the pretreament of capsular polysaccharide in the effect of hydrolysis temperature and hydrolysis time. It proved that, with increasing temperature and time, molecular weight was becoming more and more small. The larger combination molecular weight can be achieved by hydrolyzing in acetic acid at 85 ℃, with few free protein; The sodium periodate in polysaccharides pretty reacted primitively, after the polysaccharide activation reaction for 16 h. Along with the concentrations of sodium periodate increasing, activated degree and recovery rate of the polysaccharides were both decreasing. The recovery rate of the polysaccharides reached around 78%, as added 0.4 g/L sodium periodate and activated degree is about 10; Through the four optimized aspects, combined reaction time, rate of charge, the recovery rate of the polysaccharides and proteins and reaction container, were discussed in the resesch of conjugate vaccine. It proved the 4 ml system in 50 mL centrifuge tube, rate of charge is 20:10,7 times the aldehyde content in sodium borohydride, reacted at 37 ℃for 48 h, The yield of conjugate vaccine is much higher, it has no free protein in reaction media; The vaccine was prepared with puried conjugate production, high-pressure sterilizated physiological saline and 5 mmol/L succinic acid buffer at pH 5.8. Through the BALB/C mice immune test found the polysaccharides which was hydrolyzed for 1h in the condition of 85 ℃, activated degree is about 10, rate of charge is 20:10, The immunogenicity of conjugate vaccine was relatively efffective.