The Postembryonic Development of the Immunological Barrier in the Chicken Spleens.

Qian Zhang,Bing Chen,Xuejing Sun,Hong Chen,Yufei Huang,Taozhi Wang,Qiusheng Chen

doi:10.1155/2019/6279360

Abstract

The avian immune system improves with the development of the lymphoid organs. The chickens' spleen serves as the largest peripheral lymphoid organ, but little immunological research has been conducted on that spleen during postembryonic development. We investigated the blood-spleen barrier (BSB) by developing morphological architecture, resistance to the corpuscular antigen, immunocyte distribution, gene expression levels of TLR2/4 and cytokines in the spleens of hatched chickens of differing ages. Results demonstrated that the resistance of exogenous carbon particles of the BSB improved with the morphological and structural development of the chicken spleens. The cuboidal endothelial cells which lined the sheathed capillaries were gradually visible, and the discontinuous basement membrane was thickened during postembryonic development. There was an increased number of T and B cells and antigen-presenting cells in the chicken spleen between hatching and adulthood. The mRNA expression levels of TLR2/4, IL-2, IFN-γ, and TNF-α were higher two weeks after hatching, but these decreased and remain stable between 21 and 60 days. As the age increased, the BSB developed structurally and functionally. Our findings provide a better understanding of splenic immune function and the pathogenesis of avian immunology in infectious diseases.

Highlights

The spleen is the largest peripheral lymphoid organ in chickens, and it plays a significant role in both antibacterial and antiviral immune responses against acquired antigens
In order to further understand the immune function during the postembryonic development of the chicken spleen, we explored the immune barrier and the development of the morphological architecture, resistance to the exogenous carbon particles, immunocyte distribution, and immunological gene expressions in the chicken spleens of differing ages after hatching
In order to investigate the development of the blood-spleen barrier in hatched chickens, birds of differing ages were intravenously injected with India ink (Figure 1)

Summary

Introduction

The spleen is the largest peripheral lymphoid organ in chickens, and it plays a significant role in both antibacterial and antiviral immune responses against acquired antigens. Lymphocytes which migrate to the avian peripheral lymphoid organs are derived from central immune organs which proliferate and differentiate during embryonic development. Development of the peripheral lymphoid organs is closely related to immune function maintenance [1]. The spleen functions as a hematopoietic organ. Following the migration of lymphocytes and the formation of red and white pulps, the spleen plays a key role in immune responses, to blood-borne antigens [2]. It has been reported that maternal immunoglobulins from the hen are first isolated in the yolk of maturing oocytes before being transported across the yolk sac to the circulation of the developing chicken [3, 4]

Methods

Results

Conclusion