Potter K N, Li Y, Pascual V, Capra J D
Department of Microbiology, University of Texas, Southwestern Medical Center, Dallas 75235, USA.
Int Rev Immunol. 1997;14(4):291-308. doi: 10.3109/08830189709116521.
Staphylococcal protein A (SPA) is a B-cell superantigen which binds specifically to the variable region of human VH3 encoded antibodies. We undertook to identify the VH3 regions involved in the interaction with SPA by producing mutant antibodies in the baculovirus expression system. We had previously shown that a single amino acid change at position 57 in the CDR2 of a human SPA nonbinding VH3 encoded rheumatoid factor converted it to an SPA binder, implicating CDR2 in SPA binding. When regions of the mutated binder were exchanged with those from a mouse nonbinding antibody, the pattern of SPA binding indicated that residues in FR1, CDR2 and FR3 are involved in the interaction between VH3 encoded antibodies and SPA. In addition, all three regions are simultaneously required for SPA binding to occur. When any one of the three regions was altered, SPA binding was severely disrupted.
葡萄球菌蛋白A（SPA）是一种B细胞超抗原，它能特异性结合人类VH3编码抗体的可变区。我们通过在杆状病毒表达系统中产生突变抗体，来确定参与与SPA相互作用的VH3区域。我们之前已经表明，人类SPA非结合性VH3编码类风湿因子的互补决定区2（CDR2）中第57位的单个氨基酸变化可使其转变为SPA结合剂，这表明CDR2参与了SPA结合。当将突变结合剂的区域与来自小鼠非结合抗体的区域进行交换时，SPA结合模式表明，框架区1（FR1）、CDR2和框架区3（FR3）中的残基参与了VH3编码抗体与SPA之间的相互作用。此外，SPA结合需要这三个区域同时存在。当这三个区域中的任何一个发生改变时，SPA结合都会严重受损。
