MW Turner

Abstract

Mannose-binding lectin (MBL) is an important constituent of the innate immune defence system. The protein binds to the sugars decorating many microbial surfaces and subsequently activates the complement system through a specific protease called MASP-2. A comparison of the importance of the capsule and lipopolysaccharide (LPS) structures of selected Gram-negative organisms for the binding of MBL suggests that the LPS structure is of primary importance. For several clinically relevant organisms MBL binding leads to activation of C4 suggesting that this is a major pathway for oposonophagocytosis. MBL deficiency mainly results from three mutations in exon 1 of the gene and is associated with both increased susceptibility to infections and autoimmune disease. Recent evidence indicates that the protein also modulates disease severity, possibly through a dose dependent influence on cytokine production.

甘露糖結合凝集素(MBL)是先天性免疫防禦系統的重要組成部份。該蛋白與修飾微生物表面的糖類結合，隨後通過一種被稱之為 MASP-2 的特異蛋白酶啟動補體系統。對 MBL 選擇性結合的革蘭氏染色陰性菌的莢膜和脂多糖(LPS)結構進行比較，結果表明 LPS 結構最為重要。對於幾種與臨床有關的細菌而言，MBL 結合導致 C4 啟動，說明這是調理吞噬作用的主要途徑之一。MBL 缺乏主要是由該基因外顯子 1 的三種突變引起的，並與對感染和自身免疫性疾病的易感性增加有關。近來有證據表明 MBL 對疾病的輕重起著調節的作用，有可能是通過劑量改變影響細胞因數產生這一途徑。