免疫途径及载体对乙肝病毒DNA疫苗免疫效果影响的研究

目的探讨ＤＮＡ载体结构及接种途径对ＤＮＡ疫苗免疫效果的影响。方法分别构建插入ＨＢＶ表面抗原编码基因的表达载体ｐｃＤＮＡ１．１／ＳＡ（无抗性基因）和ｐｃＤＮＡＩ／Ａｍｐ／ＳＡ（含氨苄青霉素抗性基因），肌注小鼠后比较其诱生特异性免疫应答的能力；同时比较不同接种途径（肌内、皮内、皮肤划痕）及ＣｐＧ免疫刺激元件（ＩＳＳ）对ＤＮＡ疫苗诱生免疫效果的影响。结果ｐｃＤＮＡＩ／Ａｍｐ／ＳＡ的免疫效果优于ｐｃＤＮＡ１．１／ＳＡ。ｐｃＤＮＡ１．１／ＳＡ的免疫效果可被ＩＳＳ增强，而ｐｃＤＮＡＩ／Ａｍｐ／ＳＡ诱生特异性免疫应答的能力则可被ＩＳＳ抑制；诱生免疫应答的能力以肌内注射最强，皮内注射免疫其次，皮下划痕法较弱。结论不同ＨＢｓＡｇ表达载体诱生免疫应答的能力不尽相同；ＣｐＧ免疫刺激元件在决定ＤＮＡ疫苗免疫原性中起重要作用，可增强不含相应结构ＤＮＡ疫苗的免疫效果；皮内注射可诱发与肌内接种相似的免疫应答，是一种简便、有效的免疫接种途径

HBV DNA vaccine immunization the effects of DNA vector constructs and routes of gene delivery on the induction of antiviral immunity

Objective To investigate the effects of DNA vector structure and different routes of administration on the efficiency of induction of immune responses to the HBV surface antigen (HBsAg) in mice by DNA immunization. Methods DNA vectors that contained or did not contain amplicilin resistance gene (pcDNAI/Amp, pcDNA1 1) were engineered to contain HBsAg encoding gene fragments. The efficiencies of these vector constructs to prime antibody responses were compared in mice by detection of serum HBsAg specific antibody titers after intramuscular immunization. The effects of CpG motifs and routes of administration (intramuscular, intradermal and skin abrasion) on the immunogenicity of DNA vaccines were also studied. Results Recombinant vector pcDNAI/Amp/SA that contained ampicilin selection gene stimulated significantly higher levels of HBsAg specific serum antibody after intramuscular DNA injection than the pcDNA1 1/SA vector which did not contain antibiotics resistance gene. The immunogenicity of pcDNA1 1/SA was increased by coadministrating CpG containing oligos while that of pcDNAI/Amp/SA was reduced. Both intradermal gene administration and intramuscular injection could induce strong antibody responses, while skin abrasion could not. Conclusion 1 Different vector constructs induced different levels of immune responses; 2 CpG motifs present in ampicilin resistance gene play an important role in the immunogenicity of DNA vaccines; 3 Compared with intramuscular injection, intradermal adminstration was an simple and efficient way for application of DNA vaccines.