Gould Jane M, Weiser Jeffrey N
Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia 19104-6076, USA.
J Infect Dis. 2002 Aug 1;186(3):361-71. doi: 10.1086/341658. Epub 2002 Jul 10.
Numerous major bacterial pathogens in the human respiratory tract, including Streptococcus pneumoniae and Haemophilus influenzae, express cell-surface phosphorylcholine (ChoP), a ligand for the receptor for platelet-activating factor (rPAF). ChoP is also bound by C-reactive protein (CRP), which, in the presence of complement, may be bactericidal. This study found that CRP can block the attachment of bacteria expressing cell-surface ChoP to host cells. Concentrations of CRP equivalent to those on the mucosal surface of the human airway blocked most adherence of both S. pneumoniae and H. influenzae to human pharyngeal epithelial cells. ChoP-mediated adherence was also reduced in the presence of an rPAF antagonist. The antiadhesive effects of the rPAF antagonist and CRP were not additive, suggesting that CRP activity is specific to the area of adherence mediated by the receptor. The binding of CRP to ChoP and the effect of CRP on adherence were inhibited by human surfactant (primarily ChoP). The antiadhesive effect of CRP may be diminished in the terminal airway, where surfactant is abundant.
人类呼吸道中的许多主要细菌病原体，包括肺炎链球菌和流感嗜血杆菌，都表达细胞表面磷酸胆碱（ChoP），它是血小板活化因子受体（rPAF）的配体。ChoP也与C反应蛋白（CRP）结合，在补体存在的情况下，CRP可能具有杀菌作用。本研究发现，CRP可以阻止表达细胞表面ChoP的细菌附着于宿主细胞。与人类气道粘膜表面浓度相当的CRP可阻断肺炎链球菌和流感嗜血杆菌对人咽上皮细胞的大部分粘附。在rPAF拮抗剂存在的情况下，ChoP介导的粘附也会减少。rPAF拮抗剂和CRP的抗粘附作用不是相加的，这表明CRP的活性对受体介导的粘附区域具有特异性。人表面活性剂（主要是ChoP）可抑制CRP与ChoP的结合以及CRP对粘附的影响。在表面活性剂丰富的终末气道中，CRP的抗粘附作用可能会减弱。
