Antonsson P, Wingren A G, Hansson J, Kalland T, Varga M, Dohlsten M
Pharmacia and Upjohn, Lund Research Center, Sweden.
J Immunol. 1997 May 1;158(9):4245-51.
In this report, we show that despite an overall amino acid residue identity of more than 80% between the staphylococcal enterotoxins (SE) A and E, these proteins markedly differ in their absolute requirement for the MHC class II during T cell activation. The superantigens were produced as C215Fab-SE fusion proteins and analyzed for their ability to activate T cells in a MHC class II-independent manner, using C215 Ag expressing cell lines as pseudo super-APCs. C215Fab-SEA, but not C215Fab-SEE, induced T cell cytotoxicity and proliferation in these MHC class II-independent systems. Introduction of a region from SEA, comprising amino acids 20-27, to SEE transferred the ability to engage T cells in the absence of MHC class II. Analysis of the Vbeta specificity of the chimeric SEA/SEE molecules and a panel of SEA mutants demonstrated that the site for TCR interaction covers the edge surrounding the shallow cavity on top of the SEA molecule.
在本报告中，我们表明，尽管葡萄球菌肠毒素（SE）A和E之间的整体氨基酸残基同一性超过80%，但这些蛋白质在T细胞激活过程中对MHC II类分子的绝对需求上存在显著差异。超抗原作为C215Fab-SE融合蛋白产生，并使用表达C215抗原的细胞系作为假超级抗原呈递细胞（pseudo super-APCs），分析它们以不依赖MHC II类分子的方式激活T细胞的能力。在这些不依赖MHC II类分子的系统中，C215Fab-SEA而非C215Fab-SEE诱导了T细胞的细胞毒性和增殖。将SEA中包含氨基酸20 - 27的区域引入SEE，赋予了在没有MHC II类分子的情况下与T细胞结合的能力。对嵌合SEA/SEE分子和一组SEA突变体的Vβ特异性分析表明，TCR相互作用位点覆盖了SEA分子顶部浅腔周围的边缘。
