Study On The Immunosuppressive Mechanism Of Broilers Infected With Avian Leukosis Virus Subgroup J

Pathological model was established in commercial broilers at one-day-old that inoculated with ALV-J strain NX0101.Peripheral blood cells and bone marrow myelocytes were detected. The results showed that tumor cells were from acidophilic myelocytes and metamylocytes. And they transferred from bone marrow to other organs by blood or other ways.Immune organ indexs, IgG and transfer factors were detected. The results showed that growth suppression was significant at 57 days age. And the central immune organ atrophy that directedly make the index number low and indirectedly make IgG and transfer factors decreased.Dynamic changes of histopathology were studied on immune organs and some visceral organs. The results showed that ALV-J mainly made hyperplasia of eosinocytes proliferate. Even some bone marrow was substituted by these cells. This lesion was related to apoptosis of lymphocytes besides lesions of bone marrow. Myelocytes proliferated in some visceral organs.The viral glucoprotein SU was detected to show distribution of ALV-J in the immune organs by immunohistochemistry. The results showed that ALV-J was found in all immune organs. The stain of bone marrow was moderate, but not all myelocytes were positive.The positive cells were follicular reticular cells in bursa, medulla epithelial cells, plasma cells and myelocytes in thymus, medullary sinus endothelial cells, reticular cells and some myelocytes in spleen. This distribution showed the infection period of ALV-J. Apoptosis of lymphocytes in immune organs was detected by TUNEL.The results showed that ALV-J could induce incoordinate apoptosis of lymphocytes in thymus, bursa and spleen, which was mainly found at 3～5 weeks age. So it was concluded that the apoptosis of lymphocytes was the...