不同佐剂对含S+PreS1融合抗原的乙型肝炎病毒颗粒疫苗免疫原性的影响

Impact of different adjuvant on immunogenicity of the HBV particle vaccine containing the S + PreS1 fusion antigen in Balb/C mice

摘要:

本研究在前期工作基础上，用CHO细胞表达的含PreS1+S融合抗原的新型基因工程HBV颗粒疫苗 (HBSS1) 与Al(OH)3、CpG及CpG+Al(OH)3等佐剂配伍，在Balb/C小鼠模型上研究不同佐剂对HBV颗粒疫苗肌肉注射后免疫应答的影响，主要包括抗体滴度、抗体亚型分类及特异性细胞免疫 (?-IFN ELISpot检测)。结果表明：CpG佐剂结合HBSS1颗粒疫苗可快速诱导 (单针免疫) 产生高水平的抗PreS1及S抗体及较高的IgG2a/IgG1比率，同时可诱导较高抗原特异的细胞免疫应答；Al(OH)3+CpG双佐剂组一次免疫后可诱导产生最高的抗S抗体滴度 (1:105)，其产生的抗体亚类包括IgG1、IgG2a与IgG2b；在S抗原N端 (13~49 aa) 存在优势CTL表位。结论：CpG佐剂结合HBSS1颗粒疫苗应是发展新型治疗性乙肝疫苗的较佳选项。

Abstract:

We previous reported the development of novel hepatitis B virus(HBV) vaccine containing the surface antigen(S) plus PreS1 fusion derived from Chinese hamster ovary (CHO) cells system. In this study, we analyzed the impact of different adjuvants on immunogenicity of the HBV particle vaccine in Balb/C mice, including alum alone, CpG oligodeoxynucleotides (CpG-ODN) alone and CpG-ODN in combination with alum adjuvant. We first detected the antigen specific humoral response in mice, including total IgG antibody and IgG subtyping. Then, we characterized the specific cell-mediated immune (CMI) response by detection of γ-interfon secreting splenocytes after stimulating with S or PreS1 peptide pool. Our results showed that: CpG-ODN adjuvanted vaccine could rapidly induce higher level of anti-PreS1 and anti-S antibodies, and a higher ratio of IgG2a/IgG1 antibody than that of alum adjuvanted vaccine. At the same time, CpG-ODN adjuvanted vaccine induced robust antigen-specific cellular immune responses in mice, which was superior to that of alum adjuvanted vaccine and CpG-ODN in combination with alum adjuvanted vaccine; however, the vaccine candidate with CpG-ODN in combination with alum adjuvant induced highest anti-S antibody and mixed IgG subclasses in mice after twice immunization. There exists dominant HBV CMI epitopes in the N-terminal of S antigen. These results provided important evidence that CpG-ODN adjuvanted HBSS1 particles vaccine may serve as a novel method in the development of new preventive and therapeutic agents against hepatitis B infection.