流行性感冒病毒M2蛋白可溶性表达及其免疫原性的研究

流行性感冒（流感）的M2蛋白是其保护性抗原之一，在几科所有甲型流感病毒中高度保守，因此可以用来研究具有交叉保护能力的流感疫苗。然而M2分子在病毒颗粒中含量非常少，用从病毒中纯化的方法很难获得足够的免疫原。在原核表达时发现，M2蛋白对宿主菌具有很强的毒性作用，导至其死亡，因此很难获得高表达。在本研究中，采用RT－PCR方法从病毒感染的MDCK细胞中克隆了A1／PR／8／34毒株的M2基因，然后通过基因工程手段缺失了M2蛋白的跨膜区26－55位氨基酸的编码序列，将其克隆以pET-32a中，与硫氧还蛋白融合，在大肠杆菌中获得了高效表达，并且表达产物以可溶形式存在，不形成包涵体。利用硫酸铵盐析结合金属离子鏊和柱亲和层析的方法纯化了表达的融合蛋白。免疫荧光实验表明，融合蛋白免疫小鼠后产生的抗血清能够与流感病毒感染的细胞发生特异性的结合，证明表达产物具有流感病毒M2蛋白的抗原性。

Soluble Expression of Influenza Virus M2 Protein and Detection of Its Antigenicity

Influenza virus M2 is a protective as well as a highly conservative protein,so it is a suitable candidate for cross protective vaccine. In this study,we cloned M2 gene from A/PR/8/34 virus infected MDCK cells,and deleted its transmembrane domain in order to obtain high level expression.Then the mutated M2(sM2) was subcloned into the expression vector pET-32a.The recombinant plasmid could express sM2 fusion protein in a soluble form.Further,it was purified by ammonium sulphate precipitation combined with affinity chromatography.Sera collected from the mice that were immunized with the purified fusion protein could bind to influenza virus infected MDCK cells testified by immunofluorescence experiment.This indicates that the expressed fusion protein possesses M2 antigenicity.