Development of B lymphocyte in Chicken Bursa of Fabricius

[Objective] The study aimed to research the dynamic change law of B lymphocyte in chicken bursa of Fabricius from the normal chickens at different day-old.[Method] With 200 breed eggs of Hanlianbai chicken as the tested materials,the change law of development of IgM,IgG and IgA from B lymphocytes were studied in chicken bursa of Fabricius at different age-old by the immunohistochemistry method.[Result] IgM+ and IgG+ B cell could be detected out in the bursa of Fabricius on the 13 th embryonic day and the amount of IgM+B cells was more than that of IgG+B cells.IgA+ B cell could be detected out only on the 18th embryonic day.With the increasing of days old,the number of 3 kinds of IgM+,IgG+,IgA+ B lymphocyte presented the tendency to rise and was stable at 21 day-old.The distribution parts of IgM+,IgG+,IgA+ B lymphocytes were similar:they first all appeared in the epithelium mucosae,gradually distributed in the cortex and mainly distributed in the medulla after maturation.[Conclusion] IgM+B cell might appear in the bursa of Fabricius before the 13th embryonic day already.The humoral immune function of bursa of Fabricius in chicken was increased rapidly after hatching and reached the mature level at 21 day-old.