脑膜炎奈瑟球菌免疫组合物的制备及其免疫效果的检测

Preparation and immune effect of meningococcal immunogenic conjugates

目的利用不同的载体对脑膜炎奈瑟球菌(Neisseria meningitidis,Nm)A群、B群、C群、W135群和Y群进行偶联,比较不同的免疫组合物的免疫效果。方法将Nm A群、W135群和Y群多糖与CRM197偶联;将B群Nm菌种进行传代、培养、提取并纯化外膜蛋白,将外膜蛋白与C群多糖偶联。采用冻干水化法将蛋白质-多糖偶联物与脂质体(以明矾作为对照)混合后,免疫豚鼠,对不同Nm免疫组合物的杀菌滴度进行检测。结果各免疫组合物针对相应的Nm血清群具有不同的免疫作用,与C群多糖和B群外膜蛋白直接混合后免疫相比,C群多糖与B群外膜蛋白以共价键偶联后形成的免疫复合物免疫豚鼠,可引发更高滴度的杀菌抗体;而与以明矾作为佐剂相比,以脂质体作为佐剂均具有更好的免疫促进作用,其中以A群和Y群的免疫增强效果明显(P<0.05)。结论以不同抗原共价键偶联的方式较抗原直接混合后制备的Nm免疫组合物具有更高的杀菌滴度,同时以脂质体作为佐剂有利于增强脑膜炎疫苗的免疫效果。

Objective To conjugate Neisseria meningitidis （Nm） groups A, B, W135 and Y by using various carriers, and compare the immune effects of conjugates. Methods The polysaccharides of Nm groups A, W135 and Y were conjugated to CRM197. The seeds of Nm group B were subcultured, from which outer membrane protein was extracted, purified and conjugated to polysaccharide group C. The protein-polysaccharide conjugates were mixed with liposome by freeze- dried hydratation and immunized to guinea pigs, using alum as control, and determined for bactericidal titer. Results The conjugates showed various immune effects against Nm of the corresponding serogroups. Compared with that of direct mixture, the covalent conjugate of polysaccharide group C and outer membrane protein group B induced high bactericidal titer in guinea pigs. The immunopotentiation of conjugates using liposome as adjuvant was superior to that using alum as control, while the immune effects of conjugates groups A and Y were enhanced significantly （P 〈 0. 05 ）. Conclusion The immunogenic conjugates of Nm prepared with various antigens by covalent conjugation showed higher bactericidal titer than those by direct mixing. In addition, liposome as an adjuvant was beneficial to the enhancement of immune effect of Nm vaccine.