author(s)
TA Kannan, R Gnanadevi, S Senthilkumar and Geetha Ramesh

abstract
Histological and histometric details of hemal nodes in Indian buffalo were carried out. Tissue samples for the study were collected from five adult apparently healthy buffaloes slaughtered in the Corporation slaughter house, Chennai. About 4-6 hemal nodes were collected in and around the iliac arteries of the abdominal aorta. Tissue samples were fixed in 10% neural buffered formalin, sections were made and stained for histological observations and CD3 and CD79a antibodies were used for Immunohistochemical observations of T and B lymphocytes. Size of the hemal node varied from pin head to peanut size. It was surrounded by a connective tissue capsule made up predominantly of collagen fibres with few smooth muscle and reticular fibres. Subcapsular sinuses were lined by endothelium was observed. The parenchyma was not clearly divided into cortex and medulla as in the lymph nodes. It was composed of lymphoid follicles with germinal centre, interfollicular region was made up of lymphoid cords. Large, irregular sinusoid were noticed in between the cords. Immunohistochemical staining revealed the distribution of more number of T lymphocytes in the interfollicular and at the periphery of lymphoid follicles. Whereas, few T lymphocytes were also observed within the lymphoid follicle. Few B-cells were found at the mantle zone of the lymphoid follicle.