Antal J M, Cunningham J V, Goodrum K J
Department of Zoological & Biomedical Sciences, Ohio University, Athens 45701-2979.
Infect Immun. 1992 Mar;60(3):1114-21. doi: 10.1128/iai.60.3.1114-1121.1992.
The role of complement receptor type 3 (CR3) in nonopsonic recognition of group B streptococci (GBS) by macrophages was investigated. Monoclonal anti-CR3 (anti-Mac-1) inhibited phagocytosis of GBS strains by as much as 50% in serum-free cultures of both mouse peritoneal macrophages and the macrophage cell line PU5-1.8. GBS uptake was unaffected by the presence of anti-C3 or salicylhydroxamate, an inhibitor of the covalent binding reaction of C3. Soluble antibodies to LFA-1 or to the common beta-chain (CD18) of the LFA-1/CR3/p150,95 family of cell adhesion molecules did not inhibit GBS uptake. Down-modulation of surface Mac-1 on macrophages following adherence to anti-Mac-1- or anti-CD18-coated surfaces also inhibited uptake of GBS. Further evidence for GBS interaction with CR3 was demonstrated by reduction of EC3bi rosette formation in macrophages adherent to GBS-coated plates. These studies suggest that GBS can interact with macrophage CR3, promoting phagocytosis in a C3-independent fashion. In the absence of specific immunity in neonates, this recognition mechanism may be a significant virulence determinant for GBS which poorly activate the alternate complement pathway.
研究了补体受体3型（CR3）在巨噬细胞对B族链球菌（GBS）的非调理吞噬识别中的作用。在小鼠腹腔巨噬细胞和巨噬细胞系PU5-1.8的无血清培养物中，单克隆抗CR3（抗Mac-1）可使GBS菌株的吞噬作用抑制多达50%。抗C3或水杨羟肟酸（一种C3共价结合反应的抑制剂）的存在不影响GBS的摄取。针对淋巴细胞功能相关抗原-1（LFA-1）或LFA-1/CR3/p150,95细胞黏附分子家族的共同β链（CD18）的可溶性抗体不抑制GBS的摄取。巨噬细胞在黏附于抗Mac-1或抗CD18包被的表面后，其表面Mac-1的下调也抑制了GBS的摄取。通过减少黏附于GBS包被平板的巨噬细胞中EC3bi花环形成，进一步证明了GBS与CR3的相互作用。这些研究表明，GBS可与巨噬细胞CR3相互作用，以不依赖C3的方式促进吞噬作用。在新生儿缺乏特异性免疫的情况下，这种识别机制可能是GBS的一个重要毒力决定因素，GBS对替代补体途径的激活作用较弱。
