Paar M, Liebler E M, Pohlenz J F
Institut für Pathologie, Tierärztliche Hochschule Hannover, Germany.
Vet Pathol. 1992 Mar;29(2):120-8. doi: 10.1177/030098589202900204.
Uptake of macromolecules (e.g., ferritin) by M cells in follicle-associated epithelium in small and large intestine was investigated in three healthy, conventionally raised, 2- to 3-week-old, female Holstein Frisian calves. A 2.5% solution of ferritin was injected into the ligated loops in mid-jejunum, in terminal ileum, in the ascending colon adjacent to the ileocecal junction, and in the proximal loop of the ascending colon containing gut-associated lymphoid tissue. After exposure times that ranged from 82 to 165 minutes, ferritin was detected in M cells of domes in the small intestine, as well as in cells in follicle-associated epithelium of proprial lymphoid nodules and lymphoglandular complexes of colon that morphologically resembled M cells of small intestine. Ferritin was found in apical invaginations, apical vesicles, multivesicular bodies, basal vesicles, and adjacent intercellular spaces. In addition to ferritin, apical vesicles, multivesicular bodies, and intercellular spaces contained 50-nm membrane-bound particles. More ferritin was endocytosed by M cells of the small intestine than by M cells of the large intestine. In the large intestine, higher amounts of ferritin were found in M cells of follicle-associated epithelium overlying proprial lymphoid nodules than in M cells of follicle-associated epithelium in the depth of lymphoglandular complexes. Based on these results, we concluded that M cells of follicle-associated epithelium in the colon of calves provide a route for antigen uptake into the intestinal lymphoid system.
在三头健康的、按常规饲养的2至3周龄雌性荷斯坦弗里生犊牛中，研究了大小肠滤泡相关上皮中M细胞对大分子（如铁蛋白）的摄取情况。将2.5%的铁蛋白溶液注入空肠中部、回肠末端、回盲交界处附近的升结肠以及含有肠道相关淋巴组织的升结肠近端肠袢的结扎肠袢中。在82至165分钟的暴露时间后，在小肠穹窿的M细胞中以及结肠固有淋巴小结和淋巴腺复合体的滤泡相关上皮细胞中检测到铁蛋白，这些细胞在形态上类似于小肠的M细胞。在顶端内陷、顶端小泡、多泡体、基底小泡和相邻的细胞间隙中发现了铁蛋白。除铁蛋白外，顶端小泡、多泡体和细胞间隙中还含有50纳米的膜结合颗粒。小肠的M细胞比大肠的M细胞摄取的铁蛋白更多。在大肠中，覆盖固有淋巴小结的滤泡相关上皮的M细胞中发现的铁蛋白量高于淋巴腺复合体深处的滤泡相关上皮的M细胞。基于这些结果，我们得出结论，犊牛结肠中滤泡相关上皮的M细胞为抗原进入肠道淋巴系统提供了一条途径。
