包裹天然骨架CpG ODN和HBsAg的非磷脂脂质体疫苗的免疫效果

非磷脂脂质体NovasomeR○(Np )是由Brij5 2、胆固醇和油酸组成 ,可作为同时传递佐剂和抗原的载体。我们将HBsAg与天然骨架CpGODN (phosphodiesterCpGODN ,pdCpGODN )包裹于Np后免疫BALB/c小鼠 ,检测其免疫效果。结果显示 ,包裹pdCpGODN和HBsAg的Np在小鼠中诱导了很高滴度的抗 HBs抗体产生并诱生了HBsAgS2 8 3 9特异性的CTL ,而铝佐剂组和仅包裹HBsAg的Np组诱生的抗体滴度较低 ,未检测到CTL活力。抗体亚类分析结果表明包裹pdCpGODN和HBsAg的Np诱生的免疫应答类型与pdCpGODN剂量有关 ,较低剂量 (2 4 μgpdCpGODN )诱生的为IgG2a为主的Th1型应答 ,而较高剂量(4 7μgpdCpGODN )诱生的是Th1/Th2混合型应答。铝佐剂和仅包裹HBsAg的Np组诱生的是以IgG1为主的Th2型应答。此外 ,包裹pdCpGODN和HBsAg的Np免疫小鼠脾淋巴细胞在体外HBsAg刺激培养后特异性增殖并分泌高水平的IFN γ。这些结果表明包裹pdCpGODN和HBsAg的Np能增强HBsAg的免疫原性 ,诱生体液 /细胞免疫均衡应答 ,有可能发展为慢性乙肝的治疗性疫苗

The Enhanced Immune Responses Induced by Non-Phospholipid Liposome Encapsulating HBsAg and Phosphodiester CpG ODN in BALB/c Mice

Non-phospholipid liposome (Novasome,Np) composed of dioxyethylene cetyl ether,cholesterol and oleic acid were used as adjuvants and carriers. The yeast-derived HBsAg and phophodiester CpG ODN (pdCpG ODN) were encapsulated into Np and used to immunize BALB/c mice. Results showed that the Np encapsulating pdCpG ODN and HBsAg induced both the production of high titres of anti-HBs antibody and the HBsAg S 28-39-specific CTL, mice immunized with HBsAg mixed with Al(OH) 3 or Np encapsulating anti-HBsAg alone produced low titres of anti-HBs antibody and no production of CTL. Subclass analysis of the anti-HBs antibody showed that generation of the Th1-type or Th2 type immune response was relevant to the doses of pdCpG ODN,in which the low doses of pdCpG ODN (24 μg) induced Th1-biased response with predominance of IgG2a antibody production and the high doses of pdCpG ODN (47 μg) induced Th1/Th2 nixed responses. In contrast,HBsAg mixed with Al(OH) 3 or Np encapsulating anti-HBsAg alone induced Th2 type immune responses. In addition,the spleen cells obtained from mice immunized with Np encapsulating pdCpG ODN and HBsAg showed HBsAg specific proliferative response and secreted high level of IFN-γ during the cultivation with HBsAg. These results indicate that Np encapsulating pdCpG ODN and HBsAg can enhance the immunogenicity of HBsAg and generate both the humoral and cellular immune responses. This novel HBV liposome vaccine is likely to be developed as a therapeutic means against the chronic HBV infection.