Department of Biochemistry, School of Life Sciences, University of Madras, Chennai, Tamilnadu, India.
PLoS One. 2011 Jan 21;6(1):e16231. doi: 10.1371/journal.pone.0016231.
Lectins are a class of ubiquitous proteins/glycoproteins that are abundantly found in nature. Lectins have unique carbohydrate binding property and hence have been exploited as drugs against various infectious diseases. We have isolated one such novel lectin from the fruit pulp of Aegle marmelos. The isolated lectin was partially characterised and its effect against Shigella dysenteriae infection was evaluated. The isolated lectin was found to be a dimeric protein with N-acetylgalactosamine, mannose and sialic acid binding specificity. The effect of Aegle marmelos fruit lectin on the adherence of Shigella dysenteriae to human colonic epithelial cells (HT29 cells) was evaluated by Enzyme Linked Immune Sorbent Assay and invasion was analysed. The protective nature of the Aegle marmelos fruit lectin was assessed by analyzing apoptosis through dual staining method. Aegle marmelos fruit lectin significantly inhibited hemagglutination activity of Shigella and its minimum inhibitory concentration is 0.625 µg/well. Further, at this concentration lectin inhibited Shigella dysenteriae adherence and invasion of HT29 cells and protects the HT29 cells from Shigella dysenteriae induced apoptosis. To conclude, isolated lectin dimeric protein with N-acetylgalactosamine, Mannose and sialic acid binding specificity and inhibits adherence and invasion of Shigellae to HT29 cells thus, protects the host.
凝集素是一类广泛存在的蛋白质/糖蛋白，在自然界中大量存在。凝集素有独特的碳水化合物结合特性，因此被开发为治疗各种传染病的药物。我们从酸橙的果肉中分离到一种这样的新型凝集素。对分离出的凝集素进行了部分表征，并评估了其对志贺氏菌感染的作用。分离出的凝集素被发现是一种具有 N-乙酰半乳糖胺、甘露糖和唾液酸结合特异性的二聚体蛋白。通过酶联免疫吸附试验评估了酸橙果实凝集素对志贺氏菌黏附人结肠上皮细胞（HT29 细胞）的影响，并分析了侵袭情况。通过双重染色法分析细胞凋亡来评估酸橙果实凝集素的保护特性。酸橙果实凝集素显著抑制了志贺氏菌的血凝活性，其最小抑制浓度为 0.625 µg/孔。此外，在该浓度下，凝集素抑制了志贺氏菌黏附和侵袭 HT29 细胞，并保护 HT29 细胞免受志贺氏菌诱导的细胞凋亡。综上所述，分离出的凝集素二聚体蛋白具有 N-乙酰半乳糖胺、甘露糖和唾液酸结合特异性，可抑制志贺氏菌黏附和侵袭 HT29 细胞，从而保护宿主。
