Effects of dexamethasone on the pathogenesis of porcine circovirus type 2 infection in piglets.
To investigate the effect of immunosuppression on porcine circovirus type 2 (PCV2) infection, hysterectomy-produced, colostrum-deprived piglets were inoculated with the virus by the intranasal or intraperitoneal route, with or without dexamethasone (DEX) treatment. Eleven piglets aged 8 days were divided into four groups, namely group A (four animals given PCV2), B (three given PCV2 with DEX), C (two given sterile medium with DEX) and D (two given sterile medium). No significant clinical signs were observed. Histopathological and immunohistochemical examination revealed granulomatous inflammation and PCV2 antigen in the lymphoid tissues of group B piglets, but not in the other three groups. Flow cytometric analysis of peripheral blood lymphocytes showed a reduced number of CD4+ T cells in DEX-treated piglets (groups A and C). No differences between groups were observed in respect of the number of B cells, serum IgG concentration, or PCV2 antibody titre. These results indicate that DEX influenced the pathogenic effects of PCV2 infection in lymphoid organs, and that suppression of cell-mediated immunity may play a role in the aetiology of postweaning multisystemic wasting syndrome.
Kawashima
K
K
Shichinohe Research Unit, National Institute of Animal Health, Shichinohe Kamikita Uminai 31, Aomori 039-2586, Japan.
Tsunemitsu
H
H
Horino
R
R
Katsuda
K
K
Onodera
T
T
Shoji
T
T
Kubo
M
M
Haritani
M
M
Murakami
Y
Y
D000818:Animals; D000831:Animals, Newborn; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D000914:Antibodies, Viral / Q000032:analysis; D000956:Antigens, Viral / Q000032:analysis; D018173:Circoviridae Infections / Q000276:immunology / Q000473:pathology / Q000517:prevention & control* / Q000662:veterinary; D017925:Circovirus / Q000276:immunology*; D003907:Dexamethasone / Q000627:therapeutic use*; D005434:Flow Cytometry; D007150:Immunohistochemistry; D016133:Polymerase Chain Reaction; D013552:Swine
D000893:Anti-Inflammatory Agents; D000914:Antibodies, Viral; D000956:Antigens, Viral; D003907:Dexamethasone