阳离子脂质体包裹bFGF作为免疫佐剂的制备工艺研究

bFGF Entraped in Cationic Liposomes as Adjuvant:Optimization of Technical Parameters

目的考察阳离子脂质体包裹碱性成纤维细胞生长因子(bFGF)的制备工艺以及在小鼠体内的免疫效应。方法通过优化如脂质配方、药脂比、挤压次数、冻融次数以及孵化温度等各个工艺参数在保持bFGF高活性的前提下来提高bFGF的包封率。分别用bFGF阳离子脂质体、bFGF弗氏佐剂以及PBS分3组免疫4周龄Balb/c小鼠,连续免疫4次,ELISA测定各组小鼠血清的抗体滴度。结果优化得到脂质体配方为二油酰磷脂酰乙醇胺(DOPE)∶1,2-二油酰-3-三甲铵基丙烷(DOTAP)=2∶1;药脂比为7.5%;液氮速冻,4℃孵化60min,反复冻融6次;过膜挤压10次。通过工艺的改进,bFGF在脂质体中的包封率得到显著提高,达到50%。免疫实验中通过与弗氏佐剂免疫效果比较,阳离子脂质体作为佐剂产生的bFGF的抗体滴度为1∶3200,免疫效果比较令人满意。结论免疫实验中发现阳离子脂质体作为免疫佐剂,具有很好的佐剂效应。

Objective To test the immune efficiency of bFGF entraped in cationic liposomes as adiuvant in vivo. Methods The technical parameters on encapsulation were tested in each step to gain high encapsulation efficiencies, which included lipid composition, weight ratio of protein and lipids, liposome extrusion, and different conditions of freeze-thawing. The bFGF in cationic liposome, Freund＇s adjuvant, or PBS were injected （four times） to the four-week old Balb/c mice to test the immune responses. The serum antibody was measured by ELISA 13 days after each injection. Results Maximal encapsulation efficiency （about 50%） was achieved through optimized technical parameters. Cationic liposome demonstrated satisfied immune efficiency as adjuvant. Conclusion Cationic liposome is a safe and effective immunological adjuvant.