权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Functional Role of Endosomes in Transcytosis of Immunoglobulin G

内体在免疫球蛋白 G 转胞吞作用中的功能作用

基本信息

批准号：
08670019
负责人：
ICHIMURA Takao
金额：
$ 1.47万
依托单位：
Yamaguchi Prefectural University (1997)Kagawa Medical School (1996)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08670019/
关键词：
passive immunity IgG transcytosis selective transport endosome pH rab4 rab5

项目摘要

To understand the mechanism of acquiring passive immunity, selective transcytosis of immunoglobulin G (IgG) in the rat yolk sac epithelial cell was studied by the fluorescence ratiometry and immunocyto-chemistry with using a confocal laser scanning microscope (CLSM).1.The internal pH of the sorting endosome was measured after endocytic labeling with fluorescently labeled dextran followed by the dual-fluorescence ratiometry using CLSM,The pH was 6.1 in good coincidence with the pH 6.0 previously found to be optimalfor the formation of IgG-Fcreceptor complex (IgG-FcR) in vitro.2. The intracellular transport pathways of transferrin (Tf) and IgG were examined and immunocytochemically compared with the localization of GTR-binding proteins rab4, rab 5A and rab8. The rab proteins except for rab8 were colocalized with Tf and/or IgG in the sorting and/or recycling endosomes. 3. The immunocytochemical examination was repeated after chasing Tf and IgG for 15-30 min in the Presence of an antibiotics brefeldin-A (10muM). Tf was accumulated to recycling endosomes (rab4 positive), while IgG was found in sorting endosomes (rab4/rab5A positive) and IgG-carrying transcytotic vesicles (rab4/rab5A positive, rab8 negative). Transcytosis of igG was apparently little affected by brefeldin-A.These results confirm the idea that IgG-FcR is transcytosed through the mildly acidic endosomes including sorting endosomes and IgG-FcR carrying vesicles. It is suggested that rab4 and rab5A are involved in regulation of fusion/fission events on the sorting endosome. A clathrin-and COPs-independent mechanism of sorting and transport of IgG-FcR is also suggested.

为了了解获得被动免疫的机制，利用共聚焦激光扫描显微镜（CLSM），通过荧光比率测定和免疫细胞化学研究了大鼠卵黄囊上皮细胞中免疫球蛋白G（IgG）的选择性转胞吞作用。 1.内吞标记后测量分选核内体的内部pH值荧光标记的葡聚糖，然后使用CLSM进行双荧光比例测定，pH为6.1，与之前发现的体外形成IgG-FcR复合物（IgG-FcR）的最佳pH 6.0非常吻合。 2．检查转铁蛋白 (Tf) 和 IgG 的细胞内转运途径，并通过免疫细胞化学方法与 GTR 结合蛋白 rab4、rab 5A 和 rab8 的定位进行比较。除 rab8 外的 rab 蛋白与 Tf 和/或 IgG 在分选和/或回收内体中共定位。 3.在抗生素布雷菲德素-A（10μM）存在下，追踪Tf和IgG 15-30分钟后重复免疫细胞化学检查。 Tf 积累到再循环内体（rab4 阳性）中，而 IgG 则在分选内体（rab4/rab5A 阳性）和携带 IgG 的转胞吞囊泡（rab4/rab5A 阳性，rab8 阴性）中发现。显然，布雷菲德菌素-A 对 igG 的转胞吞作用影响很小。这些结果证实了 IgG-FcR 通过弱酸性内体（包括分选内体和携带 IgG-FcR 的囊泡）进行转胞吞的观点。表明 rab4 和 rab5A 参与分选内体融合/裂变事件的调节。还提出了一种独立于网格蛋白和 COP 的 IgG-FcR 分选和运输机制。