Xu Yuanfang, Sun Juan, Cui Yan, Yu Sijiu, He Junfeng, Liu Penggang, Zhang Qian
Laboratory of Animal Anatomy & Tissue Embryology, Department of Basic Veterinary Medicine, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, Gansu, China.
Gansu Province Livestock Embryo Engineering Research Center, Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, Gansu, China.
J Morphol. 2019 Feb;280(2):214-222. doi: 10.1002/jmor.20933. Epub 2018 Dec 20.
To evaluate age-related changes in the morphology as well as the expression and localization of IgA and IgG in yak pharyngeal tonsils, 20 healthy yaks were divided into four age groups [newborn (1-7 days old), juvenile (5-7 months old), adult (3-6 years old) and old (7-10 years old)]. Morphologic characteristics were observed by histological techniques. The expression and localization of IgA and IgG in pharyngeal tonsils were detected by enzyme linked immunosorbent assay (ELISA) and immunohistochemistry, respectively. The results showed that the epithelium of the pharyngeal tonsils included nonreticular epithelium with an intact basement membrane and reticular epithelium with a discontinuous basement membrane and nonepithelial cell infiltration. In newborn yaks, only primary lymphoid follicles were observed in pharyngeal tonsils. In other age groups, both primary and secondary lymphoid follicles were observed, but some of the lymphoid follicles in the old yaks were degenerated. The number of lymphoid follicles increased from the newborn to the adult group and peaked in the adult group, but the number decreased in the old group. In addition, the age-related trends of IgA and IgG protein expression were similar to those of the number of lymphoid follicles. The concentration of IgG was significantly higher than that of IgA in all age groups. Both IgA and IgG antibody secreting cells (ASCs) were distributed in the subepithelial region of the nonreticular epithelium, the reticular epithelium, the lymphoid follicles, the interfollicular areas and in between the salivary glands. The densities of IgA and IgG ASCs in pharyngeal tonsils were similar to the expression trend of both proteins in each age group. The results indicate that the morphology and amount of lymphoid follicles in yak pharyngeal tonsils vary with age. Pharyngeal tonsils produce more IgG than IgA, indicating that IgG could be significant component of mucosal immune responses in yaks.
为了评估牦牛咽扁桃体形态以及IgA和IgG的表达与定位随年龄的变化，将20头健康牦牛分为四个年龄组[新生（1 - 7日龄）、幼年（5 - 7月龄）、成年（3 - 6岁）和老年（7 - 10岁）]。通过组织学技术观察形态学特征。分别采用酶联免疫吸附测定（ELISA）和免疫组织化学检测咽扁桃体中IgA和IgG的表达与定位。结果显示，咽扁桃体上皮包括基底膜完整的非网状上皮和基底膜不连续且有非上皮细胞浸润的网状上皮。在新生牦牛的咽扁桃体中，仅观察到初级淋巴滤泡。在其他年龄组中，同时观察到初级和次级淋巴滤泡，但老年牦牛的一些淋巴滤泡出现退化。淋巴滤泡数量从新生组到成年组增加，并在成年组达到峰值，但在老年组减少。此外，IgA和IgG蛋白表达的年龄相关趋势与淋巴滤泡数量的趋势相似。在所有年龄组中，IgG的浓度均显著高于IgA。IgA和IgG抗体分泌细胞（ASC）均分布在非网状上皮、网状上皮、淋巴滤泡、滤泡间区域以及唾液腺之间的上皮下区域。咽扁桃体中IgA和IgG ASC的密度与各年龄组中两种蛋白的表达趋势相似。结果表明牦牛咽扁桃体中淋巴滤泡的形态和数量随年龄变化。咽扁桃体产生的IgG比IgA多，表明IgG可能是牦牛黏膜免疫反应的重要组成部分。
