Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: The effects of cyclophosphamide treatment on the pathogenesis of subgroup J avian leukosis virus (ALV-J) infection in broiler chickens with Marek's disease virus exposure | J. Vet. Sci. 2004 5 1 49-58 JOURNAL OF Veterinary Science The effects of cyclophosphamide treatment on the pathogenesis of subgroup J avian leukosis virus ALV-J infection in broiler chickens with Marek s disease virus exposure Yongbaek Kim Thomas P. Brown and Mary J. Pantin-Jackwood Departments of Veterinary Pathology and Avian Medicine College of Veterinary Medicine University of Georgia Athens GA 30602 USA Studies were performed to determine the effects of B-cell suppression on the pathogenesis of Subgroup J avian leukosis virus ALV-J in broiler chickens. Neonatal chickens were treated with cyclophosphamide CY or PBS and then infected with ALV-J ADOL-7501 at 2 weeks of age. CY treatment induced B cell specific immunosuppression throughout the experiment confirmed by decreased bursal weight intact lymphocyte mitogenetic activity stimulated by Con A and increased relative subpopulation of CD3-positive cells as measured by flow cytometry. Chickens in this experiment had Mareks disease virus exposure prior to three weeks of age as determined by the presence of lymphocytic infiltration and antibody. Virus neutralizing antibody against ALV-J was first observed at 6 weeks post-infection in some of the infected chickens in the PBS group. As expected none of the chickens from the CY group and uninfected chickens developed virus-neutralizing antibody. The viremic status was measured by real time RT-PCR using SYBR green I dye. The percentage of viremic chickens was significantly higher and more chickens had high titered viremia in the CY treated group. No neoplastic foci consistent with ALV-J infection were observed in any of the experimental chickens. The frequency and intensity of viral antigen expression determined by immunohistochemistry was significantly higher in tissues from CY treated birds than those of PBS treated chickens at 3 weeks post-infection. This study showed that B cell specific immunosuppression with CY treatment in chickens resulted in increase in .
