乙肝病毒核心蛋白病毒样颗粒表面抗原密度对抗体应答水平的影响  

Correlation between antigen density on the surface of hepatitis B virus core protein virus-like particles and their antibody response

作　　者：李琪 汤书兵[2] 周树敏[1] 钱志康[2] Qi Li;Shubing Tang;Shumin Zhou;Zhikang Qian(School of Life Sciences,Shanghai University,Shanghai 200000,China;CAS Key Laboratory of Molecular Virology&Immunology,Institut Pasteur of Shanghai,Chinese Academy of Sciences,Shanghai 200000,China)

机构地区：[1]上海大学生命科学学院,上海200000 [2]中国科学院上海巴斯德研究所中国科学院分子病毒与免疫重点实验室,上海200000

出　　处：《微生物学报》2019年第2期303-313,共11页Acta Microbiologica Sinica

基　　金：国家自然科学基金(81572002);国家重点研发计划项目(2016YFA0502101)~~

摘　　要：【目的】为了探究乙肝病毒核心蛋白(HepatitisBviruscoreprotein,HBc)病毒样颗粒(Virus-like particles,VLPs)表面抗原密度对免疫后抗体应答水平的影响,制备了不同抗原密度的HBc VLPs疫苗,并检测了其在小鼠体内的抗体应答水平。【方法】首先制备了N端带有3个甘氨酸的人巨细胞病毒重组抗原域AD-4作为模式抗原,接着通过Sortase A的介导将AD-4连接到HBc VLPs表面上。将系列浓度梯度AD-4抗原在SortaseA介导下分别与相同浓度的HBcVLPs发生反应,制备不同抗原密度的HBc-AD-4 VLPs。将其分别免疫6–8周龄BALB/c小鼠3次,每次免疫间隔2 w,间接ELISA法检测被免疫小鼠血清的抗体应答水平。【结果】结果表明,当HBc VLPs表面抗原密度为44.4%时,即HBc反应浓度∶AD-4反应浓度为1:0.5时,不足以引起高滴度的抗体产生;当HBc VLPs表面抗原密度为64.2%时,即HBc反应浓度∶AD-4反应浓度为1:1时,HBc-AD-4 VLPs诱导的AD-4特异性抗体滴度与100%抗原密度的HBc-AD-4VLPs所引起的抗体滴度相当;当HBcVLPs表面抗原密度大于64.2%时,引起的抗体应答水平不因抗原密度增加而进一步增强。【结论】发现了HBcVLPs表面抗原密度与免疫后抗体滴度呈正相关,然而免疫64.2%抗原密度的HBc VLPs所产生的抗体滴度可达峰值,抗原密度进一步增加,抗体应答水平不会进一步加强。[Objective]To better understand how antigen density on the surface of hepatitis B virus core protein(HBc)virus-like particles(VLPs)affects their antibody response,we generated HBc VLPs with different antigen densities,and tested their antibody response in mice.[Methods]First,we prepared the recombinant antigen domain 4(AD-4)of human cytomegalovirus(HCMV)as a model antigen,which contains three glycine molecules at its N-terminus,for Sortase A-mediated ligation onto the HBc VLPs.Displaying different densities of antigens onto the surface of VLPs was achieved by using a serial diluted recombinant AD-4 in ligation reactions.After that,HBc-AD-4 VLPs with different antigen densities were applied to 6-8 weeks old BALB/c mice.Each group was inoculated three times at 2-week intervals and the AD-4-specific IgG was detected by indirect ELISA.[Results]When the reaction concentration ratio between HBc and AD-4 is 1:0.5,which HBc surface antigen density is 44.4%,VLPs couldn’t induce a high antibody titer.When the reaction concentration ratio between HBc and AD-4 is 1:1?which HBc surface antigen density is 64.2%,VLPs could induce similar highest humoral immune response compared to 100%antigen density HBc VLPs.When HBc surface antigen density is greater than 64.2%,no further enhancement of antibody response was observed by further increasing the antigen density.[Conclusion]In conclusion,we found that antigen density on HBc VLPs is positively correlated with the antibody response.However,it reaches a peak at 64%antigen density,and no further enhancement of antibody response was observed by further increasing the antigen density.

关 键 词：病毒样颗粒 抗原密度 体液免疫 乙肝病毒核心蛋白 SORTASE A 

分 类 号：R392[医药卫生—免疫学]