Brunda M J, Minden P, Grey H M
J Immunol. 1979 Oct;123(4):1457-61.
The ability of human IgA myeloma immunoglobulins to interact with protein A-containing Staphylococcus aureus was examined. Some IgA1 and IgA2 immunoglobulins bound to S. aureus although others of both subclasses failed to do so. These results were obtained by using both direct binding of radiolabeled immunoglobulins to S. aureus and with inhibition-type assays. Binding was dependent on the Fc fragment of IgA since there was no binding to S. aureus by an F(ab')2 fragment of IgA1. Nonprotein A-containing bacteria did not bind these immunoglobulins and isolated protein A interacted with radiolabeled immunoglobulins. This strongly suggested that protein A was responsible for the observed binding to S. aureus. These data indicate, in contrast to previous reports, that there is no simple relationship between IgA subclass and the capacity to bind to protein A.
对人 IgA 骨髓瘤免疫球蛋白与含蛋白 A 的金黄色葡萄球菌相互作用的能力进行了检测。一些 IgA1 和 IgA2 免疫球蛋白能与金黄色葡萄球菌结合，尽管这两个亚类中的其他免疫球蛋白则不能。这些结果是通过放射性标记免疫球蛋白与金黄色葡萄球菌的直接结合以及抑制型试验获得的。结合依赖于 IgA 的 Fc 片段，因为 IgA1 的 F(ab')2 片段不与金黄色葡萄球菌结合。不含蛋白 A 的细菌不结合这些免疫球蛋白，而分离出的蛋白 A 与放射性标记的免疫球蛋白相互作用。这有力地表明蛋白 A 是观察到的与金黄色葡萄球菌结合的原因。与之前的报道相反，这些数据表明 IgA 亚类与结合蛋白 A 的能力之间不存在简单的关系。
