THE MORPHOLOGICAL ANALYSIS OF THE PERITONEUM IN DEFENCE SYSTEM

为了建立腹膜作为防御器官的模型，应用免疫扫描电镜（immunoSEM）观察了腹膜间皮细胞与免疫相关细胞之间的相互作用。细胞间粘附分子-1（intercellular adhesion molecules-1，ICAM-1）是IgG超家族的重要分子，与白细胞粘附迁移有关。该分子选择性地表达在腹膜的微绒毛上，并被LPS（脂多糖）上调。刺激后24小时达高峰。ICAM-1在正常和炎症状态下均发挥作用，实验性腹膜炎时，腹膜表面出现大量巨噬细胞。它们在细胞表面具有LFA-1（白细胞功能相关抗原1）和Mac-1，它们是ICAM-1的配体。Mac-1在活化状态下局限于巨噬细胞的微绒毛。腹膜微绒毛表达ICAM-1。LPS刺激后，腹膜除表达ICAM-1外，还表达VCAM-1。未检测到其他粘连（ICAM-2、ELAM-1、PECAM-1、CD 105）。VCAM-1和ICAM-1仅限于微绒毛。免疫双染显示ICAM-1和VCAM-1在腹膜表面的定位相近，表明ICAM-1在正常情况下是白细胞迁移的通道，在炎症情况下是白细胞迁移的通道。ICAM-1和VCAM-1协同将白细胞固定在腹膜上，腹膜通过ICAM-1和VCAM-1与LFA-1相互作用而起防御器官的作用，Mac-1和VLA-4。

To establish the peritoneum as defense organ, interaction between the peritoneal mesothelial cells and immuneassociated cells were analyzed morphologically through expression of cellular adhesion molecules with immunoSEM.ICAM-1 (intercellular adhesion molecule-1) is an important molecule of IgG superfamily associated with leukocyte migration through stick adhesion. This molecule was selectively expressed on the microvilli of the peritoneum and was upregulated by LPS (Lipopolysaccharide). The peak was 24 hrs after stimulation. ICAM-1 was suggested to work in both normal and inflammatory conditions.In the experimental peritonitis, a large number of macrophages appeared on the peritoneum. They had LFA-1 (leukocyte function-associated antigen 1) and Mac-1, which are ligands of ICAM-1, on the cell surface. Mac-1 was restricted to the microvilli of the macrophages in activated condition. The microvilli of the peritoneum expressed ICAM-1 moderately. It was confirmed that these abhesions was necessary for iinteraction between the peritoneum and leukocytes.The peritoneum expressed VCAM-1 in addition to ICAM-1 after LPS stimulation. Other adhesions (ICAM-2, ELAM-1, PECAM-1, CD105) were not detected. VCAM-1 was restricted to microvilli as well as ICAM-1. After both expression, s leukocytes fixed to the peritoneum Double immunostaining showed localizations of ICAM-1 and VCAM-1 were near to each other.These results showed that (1) Microvilli with ICAM-1 is a road for leukocyte migration in the normal condition and (2) in inflammation, ICAM-1 and VCAM-1 cooperate to fix leukocytes to the peritoneum and the peritoneum works as defense organ through interaction of ICAM-1 and VCAM-1 with LFA-1, Mac-1 and VLA-4.