缓释破伤风类毒素微球的制备及其免疫原性

Preparation and Immunogenicity of Controlled - released Tetanus Toxoid Microspheres

目的 用可生物降解缓释微球,单剂投递破伤风类毒毒。方法 用溶剂挥发法,将破伤风类毒素(TT)包入两种丙交酯-乙交酯共聚物制备成微球,用电镜观察微球的粒经与表面形态,用Bradford法及SDS-PAGE检测微球内蛋白含量及抗原结构的变化。TT微球免疫豚鼠后,观察抗体应答。结果 微球表面光滑,成球规律,两种微球平均粒径为8.4μm及9.7μm,包裹率为48％及56％,包裹后的TT结构未改变。TT微球免疫豚鼠后,1针诱导的抗TT-IgG及中和抗体滴度与3针铝吸附TT相似;TT微球免疫血清及铝吸附TT免疫血清与游离破伤风毒素有相似的结合特性。加强免疫后,TT微球的回忆应答优于铝佐剂疫苗。结论 可生物降解缓释微球单剂投递破伤风类毒素,可产生持续高的免疫应答。

Objective To deliver tetanus toxoid by a single administration using biodegradable micro-spheres . Methods Two kinds of biodegradable microspheres were prepared by the encapsulation of tetanus toxoid with 2 kinds of polylactide-co-glycolide (PLGA) polymers respectively using solvent evaporation technique. The surface morphology and sizes of the microspheres were observed by electron microscopy, and the antigen content and integrity were detected by Bradford method and SDS - PAGE respectively. The antibody response to TT was observed in guinea pigs. Results The microspheres were smooth and even in size. The mean diameters of the 2 kinds of microspheres were 8. 4μm and 9. 7μm, and the encapsulation rates of them were 48% and 56% respectively. No significant change was observed in the TT antigen integrity after encapsulation. Animal test showed that the anti - TT - IgG and neutralizing antibody titers induced by a single dose of TT microspheres were not significantly different from those induced by 3 doses of aluminium - adsorbed TT. The binding capacity of sera immunized with TT microspheres was also similar to that immunized with aluminium - adsorbed TT. However, the anamneotic response level induced by TT microspheres was significandy higher than that induced by aluminium - adsorbed TT. Conclusion A single dose of TT delivered by biodegradable microspheres induced continuous and high immune response level.