Bernhard W, Gbarah A, Sharon N
Department of Membrane Research and Biophysics, Weizmann Institute of Science, Rehovot, Israel.
J Leukoc Biol. 1992 Sep;52(3):343-8. doi: 10.1002/jlb.52.3.343.
Bacteria can bind specifically to phagocytic cells via lectin-carbohydrate interactions and such binding is often followed by activation and degranulation of the phagocytes, as well as uptake and killing of the bacteria, a phenomenon designated lectinophagocytosis. Although extensively studied in vitro, no direct evidence for the occurrence of lectinophagocytosis in vivo has been available. To obtain such evidence, we injected type 1 fimbriated (mannose-specific) or nonfimbriated Escherichia coli into the peritoneal cavity of mice (10(7)-10(10) bacteria/animal) in the absence or presence of sugars and quantified the phagocytic activity by assaying the release of lysosomal N-acetyl-beta-D-glucosaminidase into the peritoneal fluid, up to 45 min after injection. Following injection of the type 1 fimbriated bacteria, significant release of the enzyme was observed which was time dependent and increased with the number of bacteria injected, whereas the nonfimbriated bacteria caused only little release. Methyl alpha-D-mannoside (50 mM), but not methyl alpha-D-galactoside or sucrose, inhibited the release by 60 to 100%. No release of N-acetyl-beta-D-glucosaminidase was induced by bacteria injected into a peritoneal cavity from which the macrophages had been removed. Our findings show that lectinophagocytosis can occur in vivo and may contribute to the host's defence against type 1 fimbriated bacteria.
细菌可通过凝集素-碳水化合物相互作用特异性结合吞噬细胞，这种结合之后通常会伴随吞噬细胞的激活和脱颗粒，以及细菌的摄取和杀伤，这一现象被称为凝集素吞噬作用。尽管在体外已对此进行了广泛研究，但尚无体内发生凝集素吞噬作用的直接证据。为了获得此类证据，我们在有无糖类存在的情况下，将1型菌毛（甘露糖特异性）或无菌毛的大肠杆菌注入小鼠腹腔（每只动物10⁷ - 10¹⁰个细菌），并通过检测溶酶体N-乙酰-β-D-氨基葡萄糖苷酶释放到腹腔液中的量来量化吞噬活性，直至注射后45分钟。注射1型菌毛细菌后，观察到该酶有显著释放，其呈时间依赖性，且随注射细菌数量的增加而增加，而无菌毛细菌仅引起少量释放。α-D-甲基甘露糖苷（50 mM）可抑制60%至100%的释放，而α-D-甲基半乳糖苷或蔗糖则无此作用。向已去除巨噬细胞的腹腔内注射细菌未诱导N-乙酰-β-D-氨基葡萄糖苷酶的释放。我们的研究结果表明，凝集素吞噬作用可在体内发生，可能有助于宿主抵御1型菌毛细菌。
