Abstract

Soad A. Treesh, Amal O. Buker and Nadia S. Khair

The thymus is the major site of T cell production and an important organ of the immune system,due to lack of some information on presence of the plasma cells in thymus we study it .Thirty six apparently normal chicken which differ in age and gender were included. The tissue samples were prepared for histological,histochemical and immunohistochemical studies.The appearance of plasma cells beganat the 4 th week of age, in the medulla, and their number increased along the thymus development.In concomitant with the appearance of blood capillaries at the corticomedullary junction by 3th and 4th weeks of age and a few Hassall's corpuscles in the medulla at 4th weeks of age . These corpuscles were constantly increased in number with age, and that was demonstrated in the 21, 30 weeks-old. We concluded that, the appearance of plasma cells in chicken thymus at different ages provides further support to the idea that the thymus may function as a secondary lymphoid organ , and it is capable of playing a direct role in the immunereactions. This is important role in vaccination of chicken and in future research works.