Abe Yu, Kuroda Yasuhiro, Kuboki Noritaka, Matsushita Misao, Yokoyama Naoaki, Kojima Naoya
Department of Applied Biochemistry; Institute of Glycoscience, Tokai University, Hiratsuka, Kanagawa 259-1292, Japan.
J Biochem. 2008 Nov;144(5):563-70. doi: 10.1093/jb/mvn101. Epub 2008 Aug 11.
Peritoneal macrophages (PEMs) preferentially and rapidly take up oligomannose-coated liposomes (OMLs) and subsequently mature to induce a Th-1 immune response following administration of OMLs into the peritoneal cavity. Here, we examine the contributions of complement component C3 and complement receptor type 3 (CR3) to carbohydrate-dependent uptake of OMLs by PEMs. Effective uptake of OMLs into PEMs in vitro was observed only in the presence of peritoneal fluid (PF), and OMLs incubated with PF were incorporated by PEMs in vitro in the absence of PF. These phenomena were inhibited by methyl-alpha-mannoside, N-acetylglucosamine or EDTA, but not by galactose. Pull-down analysis followed by peptide mass fingerprinting of PF-treated OMLs indicated that the OMLs were opsonized with complement fragment iC3b. In vivo uptake of OMLs by PEMs was inhibited by intraperitoneal injection of an antibody against CR3, a receptor for iC3b, and OML uptake by PEMs in the peritoneal cavity was not observed in C3-deficient mice. Thus, our results indicate that OMLs are opsonized with iC3b in a mannose-dependent manner in the peritoneal cavity and then incorporated into PEMs via CR3.
腹膜巨噬细胞（PEMs）优先且迅速摄取寡甘露糖包被的脂质体（OMLs），随后在将OMLs注入腹腔后成熟以诱导Th-1免疫反应。在此，我们研究补体成分C3和补体3型受体（CR3）对PEMs依赖碳水化合物摄取OMLs的作用。仅在存在腹膜液（PF）的情况下，体外观察到OMLs有效摄取到PEMs中，并且在不存在PF的情况下，与PF孵育的OMLs在体外被PEMs摄取。这些现象被α-甲基甘露糖苷、N-乙酰葡糖胺或EDTA抑制，但未被半乳糖抑制。对PF处理的OMLs进行下拉分析并随后进行肽质量指纹分析表明，OMLs被补体片段iC3b调理。腹膜内注射抗CR3（iC3b的受体）抗体可抑制PEMs在体内对OMLs的摄取，并且在C3缺陷小鼠中未观察到PEMs在腹腔内对OMLs的摄取。因此，我们的结果表明，OMLs在腹腔内以甘露糖依赖的方式被iC3b调理，然后通过CR3被纳入PEMs。
