Saukkonen K, Cabellos C, Burroughs M, Prasad S, Tuomanen E
Laboratory of Microbiology, Rockefeller University, New York, New York 10021.
J Exp Med. 1991 May 1;173(5):1143-9. doi: 10.1084/jem.173.5.1143.
The adherence of Bordetella pertussis to human respiratory cilia is critical to the pathogenesis of whooping cough but the significance of bacterial attachment to macrophages has not been determined. Adherence to cilia and macrophages is mediated by two large, nonfimbrial bacterial proteins, filamentous hemagglutinin (FHA), and pertussis toxin (PT). PT and FHA both recognize carbohydrates on cilia and macrophages; FHA also contains an Arg-Gly-Asp (RGD) sequence which promotes bacterial association with the macrophage integrin complement receptor 3 (CR3). We determined that virulent B. pertussis enter and survive in mammalian macrophages in vitro and that CR3 is important for this uptake process. We then determined the relative contribution of CR3 versus carbohydrate-dependent interactions to in vivo pulmonary colonization using a rabbit model. B. pertussis colonized the lung as two approximately equal populations, one extracellular population attached to ciliary and macrophage surface glycoconjugates and another population within pulmonary macrophages. Loss of the CR3 interaction, either by mutation of FHA or treatment with antibody to CR3, disrupted accumulation of viable intracellular bacteria but did not prevent lung pathology. In contrast, elimination of carbohydrate-bound bacteria, either by a competitive receptor analogue or an anti-receptor antibody, was sufficient to prevent pulmonary edema. We propose that CR3-dependent localization of B. pertussis within macrophages promotes persistence of bacteria in the lung without pulmonary injury. On the other hand, the presence of extracellular bacteria adherent to cilia and macrophages in carbohydrate-dependent interactions is associated with pulmonary pathology.
百日咳博德特氏菌对人呼吸道纤毛的黏附对于百日咳的发病机制至关重要，但细菌与巨噬细胞的附着意义尚未明确。对纤毛和巨噬细胞的黏附由两种大型非菌毛细菌蛋白介导，即丝状血凝素（FHA）和百日咳毒素（PT）。PT和FHA都能识别纤毛和巨噬细胞上的碳水化合物；FHA还含有一个精氨酸-甘氨酸-天冬氨酸（RGD）序列，该序列促进细菌与巨噬细胞整合素补体受体3（CR3）结合。我们确定，有毒力的百日咳博德特氏菌在体外能进入哺乳动物巨噬细胞并存活，且CR3对这一摄取过程很重要。然后，我们利用兔模型确定了CR3与碳水化合物依赖性相互作用对体内肺部定植的相对贡献。百日咳博德特氏菌在肺部以两个大致相等的群体形式定植，一个细胞外群体附着在纤毛和巨噬细胞表面糖缀合物上，另一个群体存在于肺巨噬细胞内。通过FHA突变或用抗CR3抗体处理破坏CR3相互作用，会干扰活的细胞内细菌的积累，但不会阻止肺部病变。相反，通过竞争性受体类似物或抗受体抗体消除与碳水化合物结合的细菌，足以预防肺水肿。我们提出，百日咳博德特氏菌在巨噬细胞内依赖CR3的定位促进了细菌在肺部的持续存在而不造成肺部损伤。另一方面，以碳水化合物依赖性相互作用附着在纤毛和巨噬细胞上的细胞外细菌的存在与肺部病变有关。
