Taft Sarah C, Weiss Alison A
Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0524, USA.
Clin Vaccine Immunol. 2008 Sep;15(9):1330-6. doi: 10.1128/CVI.00103-08. Epub 2008 Jul 2.
Anthrax toxin protective antigen (PA) binds to its cellular receptor, and seven subunits self-associate to form a heptameric ring that mediates the cytoplasmic entry of lethal factor or edema factor. The influence of receptor type on susceptibility to anthrax toxin components was examined using Chinese hamster ovary (CHO) cells expressing the human form of one of two PA receptors: TEM8 or CMG2. Unexpectedly, PA alone, previously believed to only mediate entry of lethal factor or edema factor, was found to be toxic to CHO-TEM8 cells; cells treated with PA alone displayed reduced cell growth and decreased metabolic activity. PA-treated cells swelled and became permeable to membrane-excluded dye, suggesting that PA formed cell surface pores on CHO-TEM8 cells. While CHO-CMG2 cells were not killed by wild-type PA, they were susceptible to the PA variant, F427A. Receptor expression also conferred differences in susceptibility to edema factor.
炭疽毒素保护性抗原（PA）与其细胞受体结合，七个亚基自组装形成七聚体环，介导致死因子或水肿因子进入细胞质。使用表达两种PA受体之一（TEM8或CMG2）人源形式的中国仓鼠卵巢（CHO）细胞，研究了受体类型对炭疽毒素成分敏感性的影响。出乎意料的是，之前认为仅介导致死因子或水肿因子进入的PA单独作用时，对CHO-TEM8细胞有毒性；单独用PA处理的细胞生长减缓，代谢活性降低。PA处理的细胞肿胀，对膜排斥染料变得通透，表明PA在CHO-TEM8细胞上形成了细胞表面孔。虽然CHO-CMG2细胞不会被野生型PA杀死，但它们对PA变体F427A敏感。受体表达也导致对水肿因子的敏感性存在差异。
