J Vet Sci.  2004 Mar;5(1):49-58.

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

• Kim Y
• Brown TP
• Pantin-Jackwood MJ

Abstract

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.

Keyword

Avian leukosis virus subgroup J; cyclophospha-mide; B-cell; real time RT-PCR; chickens

MeSH Terms

Animals
Avian Leukosis/*immunology/virology
Avian leukosis virus/genetics/*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/immunology
Organic Chemicals/chemistry
Poultry Diseases/immunology/*virology
RNA, Viral/chemistry/genetics
Random Allocation
Reverse Transcriptase Polymerase Chain Reaction/veterinary
Spleen/immunology/virology
Statistics, Nonparametric
Viremia/veterinary