Regulatory mechanism of antigen-stimulated lymphocyte migration in intestinal mucosa

肠道相关淋巴组织(GALT)中的淋巴细胞在全身循环中持续循环，在肠粘膜防御中发挥重要作用。在本研究中，我们用活体荧光显微镜建立了大鼠Peyer‘s斑中淋巴细胞迁移的观察系统，并与原始T细胞相比，研究了刺激T细胞迁移模式的改变。ConA对T细胞的刺激表现出Peyer‘s斑块选择性黏附特性的丧失，如幼稚T细胞所示。另一方面，ConA激活后，T细胞与肝窦内皮细胞的黏附显著增加。经内毒素处理后，大鼠绒毛Peyer‘s斑和粘膜下小静脉内淋巴细胞卷曲和黏附增强，这种变化主要由α4整合素介导，并可通过壁内注射A群链球菌多糖(PG-PS)诱导肠炎。我们还证实了α4-整合素分子在PG-PS诱导的T淋巴细胞向肠绒毛、粘膜和Peyer‘s斑块迁移的早期阶段起作用。通过这项研究，我们能够展示T淋巴细胞-内皮细胞在淋巴细胞激活后相互作用的过程，并获得关于其调节机制的信息。

Lymphocytes from gut associated lymphoid tissue (GALT) continuously recirculate throughout systemic circulation and play an important role for intestinal mucosal defense. In this study, we have established an observatory system of lymphocyte migration in rat Peyer's patches using intravital fluorescence microscopy and investigated the altered migration pattem of stimulated T cells as compared with naive T cells. Con A-stimulation of T cells showed the loss of selective adherent properties in Peyer's patches as shown in naive T cells. On the other hand, the adherence of T cells to hepatic sinusoidal endothelium was significantly increased after Con A activation. The enhanced rolling and adherence of lymphocytes was observed in Peyer's patches and submucosal venules of villi when rats were treated with endotoxin, and these changes were mediated largely by alpha4- integrins.Intestinal inflammation was also induced by an intramural injection of peptidoglycan-polysaccharide (PG-PS) from group A streptococci into rat ileal Peyer's patches. We also demonstrated that alpha4-integrin molecule plays a role in the early stages of PG-PS induced T lymphocyte migration to intestinal villus mucosa and Peyer's patches. By this study, we were able to demonstrate the chatnges in T lymphocyte-endothelial interaction after lymphocyte activation and obtained informations about their regulatory mechanisms.