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

• Published in: Journal of veterinary science (Suwŏn-si, Korea) Vol. 5; no. 1; pp. 49 - 58
• Main Authors: Kim, Yongbaek, Brown, Thomas P, Pantin-Jackwood, Mary J
• Format: Journal Article
• Language: English
• Published: Korea (South) 대한수의학회 2004
• Subjects: Animals; Avian Leukosis - immunology; Avian Leukosis - virology; Avian Leukosis Virus - genetics; Avian Leukosis Virus - immunology; Body Weight - physiology; Bursa of Fabricius - immunology; Chickens; Concanavalin A - immunology; Cyclophosphamide - pharmacology; Flow Cytometry - veterinary; Immunocompromised Host; Immunohistochemistry - veterinary; Immunophenotyping - veterinary; Immunosuppressive Agents - pharmacology; Lymphocyte Activation - drug effects; Lymphocyte Activation - immunology; Organic Chemicals - chemistry; Poultry Diseases - immunology; Poultry Diseases - virology; Random Allocation; Reverse Transcriptase Polymerase Chain Reaction - veterinary; RNA, Viral - chemistry; RNA, Viral - genetics; Spleen - immunology; Spleen - virology; Statistics, Nonparametric; Viremia - veterinary; chickens; cyclophosphamide; real time RT-PCR; B-cell; Avian leukosis virus subgroup J
• ISSN: 1229-845X; 1976-555X
• DOI: 10.4142/jvs.2004.5.1.49

Studies were performed to determine the effects of Bcell 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 ALVJ 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 viremia and viral antigen load in tissues.