Study On The Development Of Head-associated Lymphocyte In Chicken

The head-associated lymphoid tissue consists of conjunctiva associated lymphoid tissue (CALT) and Harderian gland (HG), which plays a major role in the local immune response for the chicken. This study was selected1,7,14,21,35and56day-old chicks, each period to take the lower eye conjunctiva and Harderian gland to produce frozen sections, it is important to study the structural characteristics, developmental changes and the emergence of lymphocyte, migration, location, the number of lymphoid as well using histology and immunohistochemistry method. The aim of this study was to provide a theoretical basis for the understanding of immune status in head-associated lymphoid tissue at different ages.We observed the organizational structure of CALT and HG in chicken at different ages by HE staining method, the results showe that:the morphological characteristics of CALT and HG was age-dependent maturation. The mucous layer of CALT was gradually thicken, more and more lymphocytes concentrated in the mucous layer with the increase of age. until27-day-old, the structure of CALT was almost mature; HG is a complex structure of tubular and vesicular glands, the structure of the gland was more and more big, acini was gathered more densely, until35-day-old, the structure of CALT developed mature almostly.We studies the development process of immune cells in CALT and HG by immunohistochemical method combined with image analysis technology, the results show that:(1) the development of T cells:both both CD3+and CD8+lymphocytes appeared firstly in CALT’s mucosal layer at1-day-old, while CD4+cells appeared at4-day-old. The number of CD3+cells and CD8+cells remained stable after peaking at27-day-old, but CD4+cells were stable in35-day-old; For HG, at1-day-old, T cells and their subsets can be found in HG, and reached a stable level in56-day-old.(2) The development of B cells: the number of Bu-1+cells in the CALT increased significantly in14-day-old, it had a large distribution among lamina propria and mucosa epithelium in27-day-old and the number of visible lymphoid nodules reached the peak in35-year-old. Bu-1a+cells distributed largely among acinar and catheter with the growth of day old in HG, which reached the peak in35-old-day.(3) the development of mononuclear macrophages cells:there were mononuclear macrophages in the CALT’s mucosa intraepithelial and HG’s gland lobules interstitial. MA+cells in the cortex of CALT were gradually clear in14-day-old and stable in35-year-old. MA+cells which distributed among the perivascular began to increase in4-old-year and the number of MA+cells were stable in35-year-old.The results revealed that the immune function of head-associated lymphoid tissue in chickens developed to maturity gradually with the increase of age, and the immune function of CALT and HG reached the mature level basically at27-day-old and at35-day-old respectively.