He Zhi-Qiang, Zhang Jun, Li Shao-Wei, Lin Jian, Liu Ru-Shi, Chen Yi-Xin, Wang Ying-Bin, Xia Ning-Shao
The Key Laboratory of Ministry of Educationfor Cell Biology and Tumor Cell Engineering, Research Center for Medical molecular virology of Fujian Province, Xiamen University, Xiamen 361005, China.
Sheng Wu Gong Cheng Xue Bao. 2004 Mar;20(2):262-8.
An E. coli expressed recombinant antigen NE2 was reported to aggregate into homo-oligomer, and can induce protective antibodies on rhesus monkey, but its immunogenicty was much weak after being purified. In this study, three N-terminal extension mutant of NE2 were expressed in E. coli, one of which named HEV 239 was found to aggregate into particle. HEV 239 antigen had good reactivity with sera of hepatitis E patients. The reactivity of HEV 239 against neutralization monoclonal antibody 8C11 was similar as NE2 antigen, while the reactivity of it against another neutralization monoclonal antibody 8H3 is much better than NE2 antigen, which indicated better antigenicity of HEV 239 than NE2. The diameter of purified HEV 239 particulate antigen was between 15 nm to 30 nm. The ED50 of immunization of HEV 239 particle adsorbed by aluminum adjuvant to BALB/c mice was between 0.08 microg to 0.25 microg. In contrast, the seraconversion rate of mice immunized by NE2 antigen adsorbed by aluminium adjuvant was only 25% on 60 microg vaccination. These results suggested that HEV 239 antigen particle has better immunogenicity as well as antigenicity than those of NE2 antigen, so it is a better vaccine candidate against HEV.
据报道，大肠杆菌表达的重组抗原NE2会聚合成同源寡聚体，并且能在恒河猴体内诱导产生保护性抗体，但其纯化后免疫原性较弱。在本研究中，NE2的三个N端延伸突变体在大肠杆菌中表达，其中一个名为HEV 239的突变体被发现会聚合成颗粒。HEV 239抗原与戊型肝炎患者血清具有良好的反应性。HEV 239对中和单克隆抗体8C11的反应性与NE2抗原相似，而其对另一种中和单克隆抗体8H3的反应性比NE2抗原好得多，这表明HEV 239的抗原性优于NE2。纯化后的HEV 239颗粒抗原直径在15纳米至30纳米之间。铝佐剂吸附的HEV 239颗粒免疫BALB/c小鼠的半数有效剂量（ED50）在0.08微克至0.25微克之间。相比之下，铝佐剂吸附的NE2抗原免疫小鼠，在接种60微克时血清转化率仅为25%。这些结果表明，HEV 239抗原颗粒比NE2抗原具有更好的免疫原性和抗原性，因此它是一种更好的戊型肝炎疫苗候选物。
