Studies on translocation of immunoglobulins across intestinal epithelium. II. Immunoelectron-microscopic localization of immunoglobulins and secretory component in human intestinal mucosa.
Studies on translocation of immunoglobulins across intestinal epithelium. II. Immunoelectron-microscopic localization of immunoglobulins and secretory component in human intestinal mucosa.
复制标题
免疫球蛋白跨肠上皮易位的研究。
作者：
Y. Isobe;Y. Isobe;Shin;Shin;P. Nakane;P. Nakane;W. Brown;W. Brown
为了明确免疫球蛋白进入肠液的机制，我们用过氧化物酶标记抗体技术定位了人肠粘膜中的免疫球蛋白、免疫球蛋白、免疫球蛋白和分泌成分(SC)。光镜下可见固有层内含有免疫球蛋白A、免疫球蛋白M或免疫球蛋白G的免疫细胞。免疫球蛋白(IgA)、免疫球蛋白M(IgM)和免疫球蛋白(SC)主要分布于腺窝上皮，免疫球蛋白仅见于绒毛顶端的少数细胞。在电子显微镜水平上，SC定位于核周间隙、内质网、高尔基复合体相关球囊、细胞质小泡以及柱状上皮细胞的侧膜和基质膜。免疫球蛋白(IgA)和免疫球蛋白M(IgM)也定位于这些细胞的质膜和胞质小泡中，而不是免疫球蛋白。免疫球蛋白和SC在其他类型的上皮细胞(潘氏、杯状、内分泌)中均未发现。这些发现提供了证据：(1)肠上皮细胞合成SC的部位是分泌性柱状细胞，主要是腺腺中的柱状细胞；(2)聚合免疫球蛋白IgM和IgA是通过形成细胞质小泡的过程通过含SC的细胞转运的；(3)在跨细胞转运过程中，IgM和IgA可与SC结合(可能的部位是侧膜或基质膜或核上胞浆)；(4)单体免疫球蛋白Ig G不具有参与Ig M和Ig A转运的跨上皮细胞途径。
To define mechanisms involved in the transport of immunoglobulins into intestinal fluids, we localized IgM, IgA, IgG, and secretory component (SC) in human intestinal mucosa by the peroxidase-labeled antibody technique. At the light microscopic level, immunocytes containing IgA, IgM, or IgG were found in the lamina propria. IgA, IgM, and SC were prominent in the epithelium of gland crypts; IgG was limited to a few cells at tips of villi. At the electron-microscopic level, SC was localized to perinuclear spaces, endoplasmic reticulum, saccules associated with Golgi complexes, cytoplasmic vesicles, and lateral and basal plasma membranes of columnar epithelial cells. IgA and IgM, but not IgG, also were localized to plasma membranes and cytoplasmic vesicles of these cells. Neither the immunoglobulins nor SC was found within other types of epithelial cells (Paneth, goblet, endocrine). The findings provide evidence that (1) the site of SC synthesis in intestinal epithelium is secretory columnar cells, principally those in gland crypts; (2) the polymeric immunoglobulins IgM and IgA are translocated through such SC-containing cells by a process that involves formation of cytoplasmic vesicles; (3) IgM and IgA could combine with SC during transcellular transport (likely sites are lateral or basal plasma membranes or supranuclear cytoplasm); (4) the monomeric immunoglobulin IgG does not share the transepithelial cell route involved in IgM and IgA transport.