Verhagen C, Hoekzema R, Kijlstra A
Department of Ophthalmology, University of Amsterdam, The Netherlands.
Invest Ophthalmol Vis Sci. 1994 Jan;35(1):236-41.
The concomitant presence of complement-activation products in the cornea during inflammation is well described. The present study was undertaken to analyze the complement activity of normal human corneal tissue and to assess the presence of complement-modulating activities.
Human corneal tissue was extracted in veronal-buffered saline. The overall complement (C) activity of the human corneal extract (HCE) and the effect of HCE on serum C-activity were investigated using a hemolytic assay. Anion-exchange chromatography and gel filtration were applied for biochemical analysis of HCE. Monoclonal anti-human C3 was used to detect corneal C3 and to remove C3 from HCE by immunoadsorption.
It was found that C-activity of HCE was less than 200 U/g tissue. Experiments to test whether HCE exhibited inhibitory activity led to an unexpected result: When added to human serum dilutions, HCE caused a significant, dose-dependent increase of C-activity. Pretreatment of HCE at 56 degrees C abolished the effect. Analysis of HCE by anion-exchange chromatography revealed two C-enhancing peaks. One peak was identified as C3 whereas the identity of the other protein peak remained unknown.
Results indicate that the human cornea contains an as yet unidentified heat sensitive factor(s) able to enhance complement activity of serum. It is postulated that this factor(s) may play an important role in corneal physiology and pathology.
炎症期间角膜中补体激活产物的同时存在已有充分描述。本研究旨在分析正常人角膜组织的补体活性，并评估补体调节活性的存在情况。
在巴比妥缓冲盐溶液中提取人角膜组织。使用溶血试验研究人角膜提取物（HCE）的总补体（C）活性以及HCE对血清C活性的影响。应用阴离子交换色谱法和凝胶过滤法对HCE进行生化分析。使用单克隆抗人C3检测角膜C3，并通过免疫吸附从HCE中去除C3。
发现HCE的C活性低于200 U/g组织。测试HCE是否具有抑制活性的实验得出了一个意外结果：当添加到人血清稀释液中时，HCE导致C活性显著的剂量依赖性增加。在56℃对HCE进行预处理消除了该效应。通过阴离子交换色谱法对HCE进行分析，发现了两个补体增强峰。一个峰被鉴定为C3，而另一个蛋白峰的身份仍然未知。
结果表明，人角膜含有一种尚未鉴定的热敏感因子，能够增强血清的补体活性。推测该因子可能在角膜生理和病理过程中起重要作用。
