Fagerland J A, Arp L H
Department of Veterinary Pathology, Iowa State University, Ames 50011.
Avian Dis. 1993 Jan-Mar;37(1):10-8.
The development of bronchus-associated lymphoid tissue (BALT) in conventionally reared broiler chickens of 1 day and 1, 2, 3, 4, 6, and 8 weeks of age was studied using light and electron microscopy (scanning and transmission). BALT in these chickens resembled other mucosa-associated lymphoid tissues (MALT) in that it was composed of an altered epithelium overlying a population of lymphocytes and contained potential antigen-presenting cells, such as macrophages and dendritic cells; high endothelial venules were also present. In contrast to other MALT, epithelial cells in chicken BALT were not of the M-cell type; i.e., they lacked large numbers of apical tubules and vesicles for specialized uptake of luminal antigens. There were age-related differences in size, number, and cellular composition of BALT nodules. Lymphoid nodules were progressively larger and more numerous with increasing age. Germinal centers were present in birds 2 weeks of age and older. BALT epithelium was primarily squamous and non-ciliated in 1-day and 1-week-old chicks, becoming progressively more columnar and ciliated in older chickens. Lymphocyte infiltration of the epithelium was extensive at 1 to 4 weeks of age; in older chickens, distinct epithelial and lymphocytic compartments were separated by connective tissue.
利用光学显微镜和电子显微镜（扫描电镜和透射电镜）研究了1日龄以及1、2、3、4、6和8周龄常规饲养肉鸡支气管相关淋巴组织（BALT）的发育情况。这些鸡的BALT与其他黏膜相关淋巴组织（MALT）相似，其由覆盖淋巴细胞群的改变的上皮组成，并含有潜在的抗原呈递细胞，如巨噬细胞和树突状细胞；也存在高内皮微静脉。与其他MALT不同，鸡BALT中的上皮细胞不是M细胞类型；即，它们缺乏大量用于特异性摄取腔内抗原的顶端小管和小泡。BALT小结在大小、数量和细胞组成方面存在年龄相关差异。随着年龄增长，淋巴小结逐渐变大且数量增多。2周龄及以上的鸡存在生发中心。1日龄和1周龄雏鸡的BALT上皮主要为鳞状且无纤毛，在老龄鸡中逐渐变为柱状且有纤毛。1至4周龄时上皮的淋巴细胞浸润广泛；在老龄鸡中，明显的上皮和淋巴细胞区室被结缔组织分隔。
