Minami T, Shinomura Y, Miyagawa J, Tojo H, Okamoto M, Matsuzawa Y
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Am J Gastroenterol. 1997 Feb;92(2):289-92.
We previously reported the increased contents of group II phospholipase A2 (PLA2) in inflamed colonic mucosa of patients with Crohn's disease and ulcerative colitis (UC). However, the cellular source of the increased group II PLA2 has remained to be clarified. In the present study, we examined immunohistochemical localization of group II PLA2 in inflamed colonic mucosal biopsy samples obtained from eight patients with Crohn's disease, seven with UC, and in normal colonic mucosa of six control subjects without inflammatory bowel disease using a monoclonal antibody raised against human group II PLA2.
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On immunoblot analysis using the antibody, a single band was detected on each lane containing colonic mucosal homogenates from a control subject, a Crohn's disease patient, or a UC patient at the same position as human group II PLA2 purified from ileal mucosa. The results of immunohistochemistry showed that colonic epithelial cells in inflamed mucosa obtained from all active Crohn's disease patients examined (n = 4) contained immunoreactive group II PLA2. In four of seven patients with active UC, group II PLA2 immunoreactivity was similarly positive. No apparent group II PLA2 immunoreactivity was detected in all colonic mucosal biopsy samples obtained from inactive Crohn's disease patients (n = 4) and control subjects. The present study supports the presence of group II PLA2 in colonic epithelial cells in actively inflamed mucosa of patients with Crohn's disease and UC, which suggests that epithelial cells may serve as the cellular source of increased group II PLA2 content in inflamed colonic mucosa of these patients.
我们之前报道过，克罗恩病和溃疡性结肠炎（UC）患者炎症性结肠黏膜中II型磷脂酶A2（PLA2）的含量增加。然而，II型PLA2含量增加的细胞来源仍有待阐明。在本研究中，我们使用针对人II型PLA2产生的单克隆抗体，检测了从8例克罗恩病患者、7例UC患者获取的炎症性结肠黏膜活检样本以及6例无炎症性肠病的对照受试者的正常结肠黏膜中II型PLA2的免疫组化定位。
使用该抗体进行免疫印迹分析时，在含有对照受试者、克罗恩病患者或UC患者结肠黏膜匀浆的每条泳道上，均在与从回肠黏膜纯化的人II型PLA2相同的位置检测到一条带。免疫组化结果显示，所有接受检查的活动期克罗恩病患者（n = 4）炎症黏膜中的结肠上皮细胞均含有免疫反应性II型PLA2。7例活动期UC患者中有4例，II型PLA2免疫反应性同样呈阳性。在从不活动期克罗恩病患者（n = 4）和对照受试者获取的所有结肠黏膜活检样本中，均未检测到明显的II型PLA2免疫反应性。本研究支持在克罗恩病和UC患者活动期炎症黏膜的结肠上皮细胞中存在II型PLA2，这表明上皮细胞可能是这些患者炎症性结肠黏膜中II型PLA2含量增加的细胞来源。
