Canine distemper virus-induced depletion of uninfected lymphocytes is associated with apoptosis.
Canine distemper virus (CDV), a negative stranded RNA morbillivirus, causes a multisystemic disease in dogs, which is associated with a severe immune suppression. The aim of the study was to examine the influence of early CDV infection on leukocyte depletion, lymphopenia and virus-induced cell death in dogs infected with a virulent CDV strain. From 10 infected dogs, peripheral blood leukocytes were harvested periodically, phenotyped and analyzed for CDV antigen content and apoptosis using Annexin V-FITC and propidium iodide labeling. CDV infection induced a severe CD3+ T cell and CD21+ B cell depletion in all animals at 3 days post-infection (d.p.i.). For dogs with severe distemper, developing virus persistence in the lymphoid tissue and central nervous system, this lymphopenia lasted until the end of the experiment. Increased levels of lymphocyte apoptosis were found at 3 d.p.i., and monocyte apoptosis at 6 d.p.i. This was more prominent in the group of animals with severe distemper. At 3 d.p.i. no leukocyte infection was detectable indicating that the early lymphocyte depletion and apoptosis was not a direct consequence of virus infection. Taken together, our results demonstrate that CDV-induced lymphopenia is an early event and that the degree of lymphocyte depletion correlates with the severity of disease and virus persistence in the lymphoid tissue and central nervous system.
Schobesberger
Martina
M
Institute of Virology and Immunoprophylaxis, Sensemattstrasse 293, 3147 Mittelhäusern, Switzerland.
Summerfield
Artur
A
Doherr
Marcus G
MG
Zurbriggen
Andreas
A
Griot
Christian
C
D000818:Animals; D000956:Antigens, Viral / Q000276:immunology; D017209:Apoptosis / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology / Q000821:virology*; D001921:Brain / Q000276:immunology / Q000821:virology; D004216:Distemper / Q000097:blood / Q000276:immunology* / Q000821:virology; D004217:Distemper Virus, Canine / Q000235:genetics / Q000276:immunology*; D004285:Dogs; D005434:Flow Cytometry / Q000662:veterinary; D007150:Immunohistochemistry / Q000662:veterinary; D016130:Immunophenotyping / Q000662:veterinary; D017403:In Situ Hybridization / Q000662:veterinary; D007958:Leukocyte Count / Q000662:veterinary; D008198:Lymph Nodes / Q000276:immunology / Q000821:virology; D008231:Lymphopenia / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D019590:Nucleocapsid Proteins / Q000276:immunology; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D013047:Specific Pathogen-Free Organisms; D013601:T-Lymphocytes / Q000276:immunology / Q000821:virology*
D000956:Antigens, Viral; D019590:Nucleocapsid Proteins; D012367:RNA, Viral