Malhotra R, Willis A C, Lopez Bernal A, Thiel S, Sim R B
Department of Biochemistry, Oxford University, U.K.
Immunology. 1994 Jul;82(3):439-44.
Collectins are a group of soluble proteins, each of which has collagenous and non-collagenous globular domains, and may be complement associated and/or have lectin activity. The complement protein C1q is structurally and functionally related to the collectins. Members of the collectin family are mannan-binding protein (MBP), lung surfactant protein A, CL-43, conglutinin and lung surfactant protein D. All except the last of these proteins have been shown to interact with a single, widely distributed receptor, named collectin receptor (also called C1q receptor). It has been proposed that collectins play an important role as opsonins in innate immunity. MBP is a serum protein and has been shown to activate the classical complement pathway. MBP has also been shown to opsonize bacteria and enhance clearance of bacteria by phagocytosis. In this article we demonstrate the presence of MBP in amniotic fluid and the localization of collectin receptor on the surface of amniotic epithelium. MBP levels in amniotic fluid were found to increase sharply from about 32 weeks of gestation. Collectin receptor was purified from a cell line, FL, derived from amniotic epithelium and was shown to interact with MBP. These results suggest that MBP may play a role in the antibody-independent recognition and clearance of pathogens in the amniotic cavity, towards term.
凝集素是一组可溶性蛋白质，每一种都具有胶原和非胶原球状结构域，可能与补体相关和/或具有凝集素活性。补体蛋白C1q在结构和功能上与凝集素相关。凝集素家族成员包括甘露糖结合蛋白（MBP）、肺表面活性物质蛋白A、CL-43、胶固素和肺表面活性物质蛋白D。除了最后一种蛋白质外，所有这些蛋白质都已被证明能与一种单一的、分布广泛的受体相互作用，该受体名为凝集素受体（也称为C1q受体）。有人提出，凝集素在先天免疫中作为调理素发挥重要作用。MBP是一种血清蛋白，已被证明能激活经典补体途径。MBP也已被证明能调理细菌并增强吞噬作用对细菌的清除。在本文中，我们证明了羊水内存在MBP以及凝集素受体在羊膜上皮表面的定位。发现羊水内的MBP水平从妊娠约32周起急剧升高。凝集素受体是从源自羊膜上皮的FL细胞系中纯化出来的，并被证明能与MBP相互作用。这些结果表明，临近足月时，MBP可能在羊膜腔内病原体的非抗体依赖性识别和清除中发挥作用。
