Wang Yongjin, Zhou Licheng, Shi Huiling, Xu Hongwei, Yao Hong, Xi Xu Guang, Toyoda Tetsuya, Wang Xiaoming, Wang Tianhou
Laboratory of Wildlife Epidemic Diseases, East China Normal University, Shanghai 200062, China.
Biochem Biophys Res Commun. 2009 Jul 17;385(1):118-22. doi: 10.1016/j.bbrc.2009.04.129. Epub 2009 May 3.
The ectodomain of influenza A virus M2 protein (M2e) is composed of 24 amino acids and induces antibodies with inhibitory effect against a broad spectrum of influenza A subtypes in vitro and in vivo. Although relatively conserved, 21 M2e variants emerged in recent influenza A strains, most of the mutations appeared in the middle part of M2e domain. In this study, we characterized the in vitro inhibition efficacy of a monoclonal antibody (mAb) M2e8-7 recognizing the N terminus highly conserved epitope SLLTEVET (aa 2-9) which is common for both M1 and M2 proteins. Peptide binding assay showed that mAb M2e8-7 reacted strongly with M2e and 19 M2e variant peptides. The mAb M2e8-7 potently inhibited the replication of influenza A virus H1 and H3 subtypes in MDCK cells. Two important amino acids in M2e epitope, Threonine at position five and the Glutamic acid at position six, were identified to lead antibody-escaping variants. These results brought new insight in developing vaccine and therapeutic agents against influenza A virus infections.
甲型流感病毒M2蛋白（M2e）的胞外域由24个氨基酸组成，在体外和体内均可诱导产生对多种甲型流感病毒亚型具有抑制作用的抗体。尽管M2e相对保守，但在近期的甲型流感病毒株中出现了21种M2e变体，大多数突变出现在M2e结构域的中部。在本研究中，我们对一种识别N端高度保守表位SLLTEVET（氨基酸2 - 9）的单克隆抗体（mAb）M2e8 - 7的体外抑制效果进行了表征，该表位是M1和M2蛋白共有的。肽结合试验表明，mAb M2e8 - 7与M2e及19种M2e变体肽强烈反应。mAb M2e8 - 7有效抑制了甲型流感病毒H1和H3亚型在MDCK细胞中的复制。M2e表位中的两个重要氨基酸，即第5位的苏氨酸和第6位的谷氨酸，被确定会导致抗体逃逸变体。这些结果为开发针对甲型流感病毒感染疫苗和治疗药物带来了新的见解。
