猪呼吸道淋巴组织发育的亚显微结构变化

应用组织学和电镜技术研究猪呼吸道发育过程中淋巴组织的变化。结果表明：扁桃体和咽部是呼吸道进入机体的第一个淋巴组织集中的部位，弥散淋巴组织在出生时就存在，淋巴小结不明显；20日龄时扁桃体中淋巴组织增生，淋巴小结清晰可见；120日龄淋巴小结数量增加，紧靠鳞状上皮密集排列，淋巴小结发育很好，并出现生发中心。扁桃体复层鳞状上皮中含有大量的上皮内淋巴细胞。气管叉是呼吸道进入机体的第二个淋巴组织集中的部位，出生时气管叉外膜中淋巴组织直接与气管支气管淋巴结相连，淋巴组织明显可见。20日龄时气管叉外膜中淋巴组织已分开，形成气管叉外膜密集的淋巴组织和气管支气管淋巴结两个部分。120日龄时气管叉处淋巴组织特别发达，黏膜上皮中上皮内淋巴细胞数量也显著增加。肺内气管和细支气管固有膜中均有较多的淋巴细胞，其中浆细胞数量增加，上皮中仍存在少量的上皮内淋巴细胞。本试验结果提示猪呼吸道是黏膜免疫较理想的诱导位点和效应位点，新生仔猪通过鼻腔免疫可提高呼吸道局部黏膜免疫力。

Ultrastructure Observation on the Ontogeny of Respiratory Tract Lymphoid Tissues in the Pig

Histology method and electron microscopy technique were used to investigate the changes of respiratory tract lymphoid tissues in pig during growth. The result showed that tonsil and pharynx were the first place of lymphoid tissue aggregation for respiratory tract entering the body. Lymphoid tissue in the tonsil existed at birth without any apparent lymph nodule aggregations. Lymphoid tissue began to increase at 20 days, with clear lymph nodule aggregations. The lymph nodules increased and densely packed beneath the stratified squamous epithelium of tonsils at 120 days. The well-developed lymph nodules were present with germinal center. A number of intraepithelial lymphocytes were located between the stratified squamous epithelium of tonsil. The bifurcation of trachea is the second place of lymphoid tissue aggregation for respiratory tract entering the body. The apparent lymphoid tissue in the adventitia of trachea bifurcation linked with tracheobronchial lymph nodule at birth, whereas they divided into two parts at 20 days. the packed lymphoid tissue in the adventitia of trachea bifurcation and tracheobronchial lymph nodule. The trachea bifurcation was rich with lymphoid tissue with increased intraepithelial lymphocytes at 120 days. More lymphocytes were located in the laminal propria of branches and bronchioles in the lung. The number of plasma cells increased and few intraepithelial lymphocytes existed between the columnar epithelium. Our results showed that the respiratory tract of pig was the effective induction sites and effective sites of mucosal immune. The local immunity in the respiratory tract can be enhanced by the nasal immunity in the piglet.