Israel E J, Taylor S, Wu Z, Mizoguchi E, Blumberg R S, Bhan A, Simister N E
Harvard Medical School, Department of Pediatrics, Massachusetts General Hospital, Boston.
Immunology. 1997 Sep;92(1):69-74. doi: 10.1046/j.1365-2567.1997.00326.x.
Maternal IgG is transferred to the suckling mouse and rat through a major histocompatibility complex (MHC) class I-related Fc receptor (FcRn) on the brush border of the proximal small intestine. We have previously described a site on the epithelial surface of the human fetal intestine with IgG binding characteristics similar to FcRn. We report here the identification by reverse transcriptase polymerase chain reaction amplification and sequencing of the human orthologue of rat and mouse FcRn in tissue obtained from human fetal and adult intestine. FcRn protein was detected in adult human intestine by western blot. Immunohistochemical studies of sections of human intestine show that the FcRn is localized mostly to the epithelial cells, where it is in the apical region. These data suggest that the binding of IgG previously seen in the fetal intestine is due to the presence of FcRn. Potential roles for this MHC class I-like Fc receptor in the human intestine include the transfer of passive immunity, induction of oral tolerance, and immunosurveillance.
母体免疫球蛋白G（IgG）通过位于近端小肠刷状缘的主要组织相容性复合体（MHC）I类相关Fc受体（FcRn）转移至哺乳的小鼠和大鼠体内。我们之前曾描述过人类胎儿肠道上皮表面存在一个具有与FcRn相似IgG结合特性的位点。我们在此报告，通过逆转录聚合酶链反应扩增和测序，在取自人类胎儿和成人肠道的组织中鉴定出大鼠和小鼠FcRn的人类同源物。通过蛋白质免疫印迹法在成人肠道中检测到了FcRn蛋白。对人类肠道切片的免疫组织化学研究表明，FcRn主要定位于上皮细胞，且位于顶端区域。这些数据表明，之前在胎儿肠道中观察到的IgG结合现象是由于FcRn的存在。这种MHC I类样Fc受体在人类肠道中的潜在作用包括被动免疫的转移、口服耐受的诱导以及免疫监视。
