In vivo analysis of molecular mechanism of lymphocyte migration in Peyer's patch

肠道相关淋巴组织（GALT）在肠道粘膜防御食物和细菌抗原中起重要作用。在这项研究中，我们建立了一个观察系统的淋巴细胞迁移在大鼠派尔集合淋巴结使用活体荧光显微镜。荧光标记的淋巴细胞在Peyer集合淋巴结的毛细血管后小静脉（PCV）上沿小静脉壁短暂滚动沿着。粘附到小静脉的淋巴细胞在10-20分钟时数量增加，CD 4+细胞优先粘附到25-50 μ m的小静脉，B细胞粘附到更宽尺寸范围的小静脉。在这个粘附过程中，粘附分子，α 4-整合素，L-选择素和CD 18/ICAM-1被证明参与。特别是我们证明了α 4-整联蛋白分子在派尔集合淋巴结中T淋巴细胞迁移的早期阶段起着关键作用。30 min后，PCV中的淋巴细胞开始渗出，并进入淋巴结。B细胞比CD 4+细胞更快地从小静脉迁移。随后，T淋巴细胞优先出现在滤泡旁微囊，而很少有B细胞被转运到微囊。我们还发现α 4-整合素在派尔集合淋巴结PCV中T淋巴细胞的跨内皮迁移过程中起着重要作用。脂肪吸收显著增强了T细胞的滚动和粘附以及随后的向微血管的迁移。另一方面，血管活性肠肽（vasoactive intestinal peptide，VIP）在不影响淋巴细胞粘附PCV的情况下，显著抑制淋巴细胞的跨内皮迁移和淋巴转运。

Gut associated lymphoid tissue (GALT) plays an important role for intestinal mucosal defense against dietary and bacterial antigens. In this study, we have established an observatory system of lymphocyte migration in rat Peyer's patches using intravital fluorescence microscopy. Fluorescence labeled lymphocytes adhered to the postcapillary venules (PCV) of Peyer's patches after transient rolling along venular walls. Lymphocytes sticking to the venules increased in number at 10-20 minutes, with preferential adherence of CD4+ cells to venules of 25-50 mum and adherence of B cells to the venules of a wider size range. In this sticking process, adhesion molecules, alpha4-intgerin, L-selectin and CD18/ICAM-1 are shown to be involved. Especially we demonstrated that alpha4-integrin molecule plays a critical role in the early stages of T lymphocyte migration in Peyer's patches. After 30 min, lymphocytes started to extravasate from PCV moved into the interstitium. B cells migrated from venules more quickly than CD4+ cells. Subsequently T lymphocytes preferentially appeared in parafollicular microlymphatics, while few B cells were transported to lymphatics. We also found that alpha4-integrin plays a significant role in the process of transendothelial migration of T lymphocytes in PCV of Peyer's patches. Fat absorption significantly enhanced the rolling and sticking of T cells and subsequent migration into microlymphatics. On the other hand, vasoactive intestinal peptide (VIP) significantly inhibited the transendothelial migration and lymphatic transport without affecting lymphocyte adherence to PCV.By this study, we were able to demonstrate the sequential migration process of lymphocye subpopulations and obtained informations about their regulatory mechanisms.