Farstad I N, Halstensen T S, Lazarovits A I, Norstein J, Fausa O, Brandtzaeg P
Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), University of Oslo, Rikshospitalet, Norway.
Scand J Immunol. 1995 Dec;42(6):662-72. doi: 10.1111/j.1365-3083.1995.tb03709.x.
Interactions between homing receptors on circulating leucocytes and endothelial addressins regulate tissue-specific cellular extravasation. Although integrin alpha 4 beta 7 appears to be the main receptor for gut-homing T lymphocytes, less is known about molecules mediating mucosal B cell homing. Expression of integrin alpha 4 beta 7 on B lymphocytes, B cell blasts, and plasma cells in human gut-associated lymphoid tissue (GALT; the Peyer's patches and appendix) and lamina propria was studied by multi-colour immunofluorescence applied on cryosections. Isolated mononuclear cells from the same tissue compartments were examined by flow cytometry and compared with peripheral blood B cells. Integrin alpha 4 beta 7 was expressed by IgA+ B cell blasts and plasma cells (CD38high) in the lamina propria, B cell blasts in GALT, and sIgD+ B lymphocytes in peripheral blood. In contrast, GALT sIgD+ B lymphocytes were negative or only weakly positive for alpha 4 beta 7. These results suggested that B lymphocytes down-regulate alpha 4 beta 7 upon extravasation in GALT but up-regulate this integrin after antigen-priming. Thus, alpha 4 beta 7 may be a homing receptor also for B cell blasts extravasating in the gut lamina propria, where this integrin is maintained on plasma cells, perhaps as a local retention factor.
循环白细胞上的归巢受体与内皮地址素之间的相互作用调节组织特异性细胞外渗。尽管整合素α4β7似乎是肠道归巢T淋巴细胞的主要受体，但关于介导黏膜B细胞归巢的分子了解较少。通过对冷冻切片应用多色免疫荧光，研究了整合素α4β7在人肠道相关淋巴组织（GALT；派尔集合淋巴结和阑尾）和固有层中的B淋巴细胞、B细胞母细胞和浆细胞上的表达。通过流式细胞术检查来自相同组织区室的分离单核细胞，并与外周血B细胞进行比较。整合素α4β7在固有层中的IgA+B细胞母细胞和浆细胞（CD38高）、GALT中的B细胞母细胞以及外周血中的sIgD+B淋巴细胞中表达。相比之下，GALT中的sIgD+B淋巴细胞对α4β7呈阴性或仅弱阳性。这些结果表明，B淋巴细胞在GALT外渗后下调α4β7，但在抗原激发后上调这种整合素。因此，α4β7可能也是在肠道固有层外渗的B细胞母细胞的归巢受体，在那里这种整合素在浆细胞上维持表达，可能作为一种局部滞留因子。
