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目的比较白喉无毒突变体(cross-reactive material 197,CRM197)、白喉类毒素(diphtheria toxoid,DT)及破伤风类毒素(tetanus toxoid,TT)3种不同载体蛋白C群脑膜炎球菌荚膜多糖(group C meningococcal polysaccharide,GCMP)结合疫苗在小鼠体内的免疫原性。方法在碳二亚胺[N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride,EDAC]的缩合作用下,将TT和DT用1,6-己二酰肼(1,6-adipic acid dihydrazide,ADH)进行衍生,制备TTAH及DT-AH衍生物,GCMP再分别与TT-AH、DT-AH及CRM197共价结合制备结合物,经Sepharose 4FF凝胶柱分离纯化后,进行化学检测、相对分子质量测定及鉴别试验。用GCMP及3种结合物经皮下注射NIH小鼠,第0、14、28天各免疫1次,分别于首免后第7、21和35天经小鼠颈动脉采血,分离血清,ELISA法检测抗体效价。结果GCMP-TT和GCMP-DT的糖/蛋白比及多糖回收率较高,GCMP-CRM197较低,3种结合物游离多糖的含量均在5%以下,相对分子质量分别为5.8×10~6、2.8×10~6、1.1×10~6,且均可与GCMP的诊断血清产生沉淀线。3种结合物在小鼠体内均能产生良好的免疫原性,抗体水平均明显高于多糖组(P<0.05);免疫2针后,GCMP-TT与GCMPDT组的抗体水平差异无统计学意义(P>0.05),而GCMP-TT和GCMP-DT组的抗体水平明显高于GCMP-CRM197组(P<0.05);免疫3针后,GCMP-TT组小鼠产生抗体水平明显高于GCMP-DT及GCMP-CRM197组(P<0.05)。结论 3种不同载体的GCMP结合物免疫小鼠后均可产生良好的免疫应答,对于共价结合的方法,载体蛋白TT优于其他两种载体。
Objective To compare the immunogenicity of meningococcal capsular polysaccharide of three different carrier protein C of cross-reactive material 197 (CRM197), diphtheria toxoid (DT) and tetanus toxoid (TT) (Group C meningococcal polysaccharide, GCMP) conjugate vaccine in mice immunogenicity. Methods TT and DT were treated with 1, 6-adipic acid dihydrazide (1, 4-dimethylaminopropyl) carbodiimide hydrochloride under the condensation of N- (3-Dimethylaminopropyl) -N’-ethylcarbodiimide hydrochloride ADH) to prepare TTAH and DT-AH derivatives. GCMP was then covalently combined with TT-AH, DT-AH and CRM197 to prepare the conjugate. The conjugates were separated and purified by Sepharose 4FF gel column. Quality Assay and Identification Test. NIH mice were injected subcutaneously with GCMP and three conjugates. The mice were immunized on the 0th, 14th and 28th days respectively. Serum was collected from the carotid arteries on the 7th, 21st and 35th day after the first immunization, Antibody titers were measured. Results GCMP-TT and GCMP-DT had higher GC / MS and polysaccharide recoveries, lower GCMP-CRM197 content, less than 5% free polysaccharide and relative molecular mass of 5.8 × 10-6 , 2.8 × 10 ~ 6, 1.1 × 10 ~ 6, and all can produce precipitation line with the diagnostic serum of GCMP. The three kinds of conjugates could produce good immunogenicity in mice, the antibody levels were significantly higher than that of the polysaccharide group (P <0.05). There was no significant difference in antibody levels between the GCMP-TT and GCMPDT groups (P> 0.05). The levels of antibody in GCMP-TT and GCMP-DT groups were significantly higher than that in GCMP-CRM197 group (P <0.05) DT and GCMP-CRM197 groups (P <0.05). Conclusion GCMP conjugates of three different carriers can produce a good immune response after immunized mice. For the covalent binding method, the carrier protein TT is superior to the other two vectors.