Tissue distribution of B-lymphocyte subsets (IgA, IgG and IgM) in the mucosa and lymphoid tissues of broilers immunized with Gumboro vaccine

The present research was designed to study the histological and immunohistochemical changes of lymphoid organs (bursa of Fabricius and cecal tonsil) and in the ileum (representative mucosal organ) of broiler chickens after immunization with Gumboro vaccine. Two groups (n=24) of Cobb-500 broiler chickens were reared in a same environment A mild vaccine (BUR ® 706) followed by a intermediate (Nobilis ® Gumboro 228 E) type vaccine was administered for immunization of chickens and samples were collected at 7 days interval for up to 32 days of age. The conventional histological structure of all three organs of the present study was similar to the earlier reports. In addition, in the bursa of Fabricius, the population of lymphocytes and the size of the follicles were found to increase in vaccinated chickens than the control chickens. The Igs positive cells (IgA, IgG and IgM) were distributed principally beneath the capsule, around the follicles and in the cortex and medulla. The frequencies of IgG- and IgM- positive cells were more than the IgA-positive cells in the bursa of vaccinated group. IgM-positive cells became peak at day 25 and started to decline at day 32 in the bursa of Fabricius of vaccinated groups of chickens. In the cecal tonsils and ileum, the Igs positive cells (IgA, IgG and IgM) distributed around the intestinal gland and within the lymphatic nodules of the lamina propria, in the core of the villi, and within the epithelium in both the control and vaccinated chickens. Their frequency per 0.1 mm 2 area of the lamina propria and in the epithelium was increased abruptly in the vaccinated group than the control broiler chickens. Like bursa, in the cecal tonsil and ileum of vaccinated chickens, the frequencies of IgG- and IgM-positive cells were also more than IgA-positive cells. The present study suggested that, the Igs positive cells were greatly accelerated in the vaccinated chickens than the control chickens and it may be due to immunomodulatory effect of vaccine. DOI: http://dx.doi.org/10.3329/bjvm.v11i1.14154 Bangl. J. Vet. Med. (2013). 11 (1): 13-19