不同日龄鸡肺脏中MHC-Ⅱ+细胞的分布规律

Distribution Regularity of MHC-Ⅱ+Cells in Lungs of Chickens at Different Ages

为了解鸡肺脏不同时期的免疫状态,本实验选择不同日龄的海兰白鸡的肺脏组织,利用免疫组织化学方法研究MHC-Ⅱ细胞的出现、定位分布及数量变化过程。结果显示,MHC-Ⅱ细胞最初于胚胎13 d出现。胚胎13 d至18 d期间,MHC-Ⅱ细胞数量有所增多,并主要分布在三级支气管的肺房房间隔中。1日龄时,MHC-Ⅱ细胞在小叶间结缔组织中也有分布。4日龄时,在初级支气管与次级支气管交汇处有淋巴细胞的聚集物,即形成了明显的支气管相关性淋巴组织(BALT),此时BALT中的大多数细胞都表达MHC-Ⅱ,成为主要的细胞群体。7至14日龄时,MHC-Ⅱ细胞数量逐渐增加,在呼吸性毛细管管壁上出现较多的MHC-Ⅱ细胞。21至90日龄时,无论是BALT中,还是肺小叶中MHC-Ⅱ细胞的数量都持续增加,并且遍布于整个肺脏。结果表明,鸡肺脏中MHC-Ⅱ细胞的分布和数量均呈现日龄相关性变化,并且其变化可以反映出胚胎期及出壳初期肺脏中抗原呈递细胞较少,随后日龄显著增多,从而进行有效的抗原递呈,参与免疫应答。

In order to understand the immune status of chicken lungs at different stages,the lung tissues of Hy-line variety white chickens at different ages were selected to study the appearance,localization and quantity changes of MHC-Ⅱ+cells by immunohistochemical method.The results showed that MHC-Ⅱ+cells initially appeared at the age of 13 days old.The number of MHC-Ⅱ+cells increased from 13 days to 18 days old,and mainly distributed in the interatrial septa of tertiary bronchi.At 1-day-old,MHC-Ⅱ+cells were also distributed in interlobular connective tissue.At the age of 4 days,there was an aggregation of lymphocytes at the confluence of primary and secondary bronchi,which formed obvious broncho-associated lymphoid tissue(BALT).At this time,most of the cells in BALT expressed MHC-Ⅱ+and became the main cell population.From 7 to 14 days old,the number of MHC-Ⅱ+cells increased gradually,and more MHC-Ⅱ+cells appeared on the respiratory capillary wall.From 21 to 90 days of age,the number of MHC-Ⅱ+cells in BALT and pulmonary lobules increased continuously,and spread throughout the whole lung.The results showed that the distribution and number of MHC-Ⅱ+cells in the lung of chicken showed age-related changes,and the changes could reflect that there were less antigen-presenting cells in the lung of embryo and early shell stage,and then the number of MHC-Ⅱ+cells increased significantly at the age of day,so as to carry out effective antigen presentation and participate in immune response.