Shiojiri N, Takahashi M
Department of Biology, Faculty of Science, Shizuoka University, Japan.
J Anat. 1991 Apr;175:237-49.
The colonisation of lymphoid stem cells and the following lymphoid follicle formation in the bursa of Fabricius of the chick embryo was studied histochemically and morphologically. Most basophilic haematopoietic stem cells first appeared in the mesenchyme of the distal bursa at 7 and 8 days. Basophilic cells were also seen in the loose connective tissue near the distal bursa, and in the vessels which were located dorsal to the distal bursa. They began to invade the epithelium at 10 and 11 days of incubation by digesting the basal laminar components which the fluorescent lectin probes stained. Haematopoietic stem cells were in close association with the extracellular matrix in the mesenchyme and contained abundant F-actin. F-actin also increased in the epithelial cells surrounding basophilic haematopoietic stem cells during lymphoid follicle formation. F-actin in migrating haematopoietic stem cells and epithelial cells might be involved in the migration of haematopoietic cells and the histogenesis of the lymphoid follicles. Granulopoiesis occurred mainly in the bursal mesenchyme, but some granulocytes were seen in the epithelium. The results support the extrinsic origin of the bursal lymphoid stem cells and their active migration towards the epithelium in the chick embryo. Cell-cell interactions and tissue interactions in the lymphoid follicle formation are also discussed.
对鸡胚法氏囊中淋巴干细胞的定植以及随后淋巴滤泡的形成进行了组织化学和形态学研究。大多数嗜碱性造血干细胞最早在7至8天时出现在法氏囊远端的间充质中。在法氏囊远端附近的疏松结缔组织以及位于法氏囊远端背侧的血管中也可见嗜碱性细胞。在孵化10至11天时，它们开始通过消化荧光凝集素探针染色的基底膜成分侵入上皮。造血干细胞与间充质中的细胞外基质紧密相连，并含有丰富的F-肌动蛋白。在淋巴滤泡形成过程中，嗜碱性造血干细胞周围的上皮细胞中的F-肌动蛋白也增加。迁移的造血干细胞和上皮细胞中的F-肌动蛋白可能参与造血细胞的迁移和淋巴滤泡的组织发生。粒细胞生成主要发生在法氏囊间充质中，但在上皮中也可见到一些粒细胞。这些结果支持了鸡胚中法氏囊淋巴干细胞的外在起源及其向上皮的活跃迁移。还讨论了淋巴滤泡形成中的细胞间相互作用和组织相互作用。
