三种常见人呼吸道腺病毒六邻体蛋白的克隆、表达及抗原性分析

Cloning and expression of hexon protein of human respiratory adenovirus of three serotypes and analysis of antigenicity of the recombinant proteins

目的：克隆、表达常见的人呼吸道腺病毒的主要中和抗原六邻体蛋白，分析重组表达产物的抗原性和免疫原性。方法分别PCR扩增克隆人3型、4型、7型腺病毒完整的六邻体蛋白基因，测序和序列比对并与GenBank上人腺病毒的六邻体蛋白进行同源性比对；对其主要的抗原区进行克隆、表达和纯化，表达产物免疫动物，ELISA和Western blot实验对表达产物的抗原性和免疫原性及其交叉反应进行分析。结果国内首次报道1株人4型腺病毒的六邻体基因序列，与GenBank中的NHRC3分离株核酸及氨基酸的同源性均大于99％；3种腺病毒包含全部高变区的六邻体部分区段在大肠杆菌中成功表达并纯化，重组蛋白可以被不同型别的人腺病毒免疫血清识别，重组蛋白免疫小鼠血清可以识别不同型别的人腺病毒，而型间反应有显著差异，预测了3种腺病毒六邻体型、型间特异性表位。结论成功表达人3型、4型、7型腺病毒六邻体蛋白主要抗原区，重组表达产物有强免疫原性，包含型间、型特异性抗原表位。

Objective To clone and express the hexon protein of three prevalent human adenovi -rus strains causing respiratory disease and analyze the antigenic characteristics of the recombinant proteins . Methods The full length genes encoding hexon protein of human adenovirus serotype 3（HAdV3）, serotype 4（HAdV4） and serotype 7（HAdV7） were cloned by PCR and sequenced , respectively.The alignment anal-ysis was performed by using hexon gene sequences from GenBank .The major antigenic regions of hexon pro-tein of the three serotypes were expressed in E.coli and purified.The antigenicity, immunogenicity and cross reactivity of the recombinant proteins were determined by ELISA and Western blot assay .Results The full length gene sequence encoding hexon protein of human adenovirus serotype 4 was firstly reported in China , which showed more than 99%homology in both nucleotide and amino acid sequences with the human adeno-virus type 4 NHRC3 strain.The partial hexon protein sequence of HAdV 3, HAdV4 and HAdV7 containing all of the 7 hyperviriable regions （ HVRs） were expressed in E.coli, respectively .The purified recombinant proteins could be recognized by antiserum of the three serotypes of adenovirus .The antiserum samples against the three recombinant proteins could cross-react with particles of the three serotypes of adenovirus . The possible type-and species-specific epitopes were predicted .Conclusion The major antigenic regions of hexon protein of the three serotypes were successfully expressed .The purified recombinant proteins contai-ning both intertypes and type-specific epitopes showed a strong immunogenicity .