Detection of cellular cytokine mRNA expression during orf virus infection in sheep: differential interferon-gamma mRNA expression by cells in primary versus reinfection skin lesions.
In sheep infected with the parapoxvirus orf virus, primary infection orf skin lesions developed and resolved within 8 weeks. Reinfection lesions were smaller and resolved within 3 weeks. The host response in the skin was characterized by an accumulation of neutrophils, dendritic cells, CD4+ T cells, CD8+ T cells, B cells and T19+ gammadelta T cells. The magnitude of this accumulation paralleled orf virus replication in the skin. In situ hybridization was used to detect cells expressing interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and interleukin-4 (IL-4) mRNAs in orf skin. Cells expressing IL-4 mRNA were not detected at any time after infection. Cells expressing IFN-gamma mRNA were detected after reinfection but not after primary infection. Cells expressing TNF-alpha mRNA included epidermal cells, vascular endothelium and uncharacterized cells that increased more rapidly in the skin after reinfection compared to primary infection. The results are consistent with a prominent role for IFN-gamma in the host immune response controlling the severity of the disease.
Anderson
I E
IE
Moredun Research Institute, International Research Centre, Pentlands Science Park, Bush Loan, Penicuik, Midlothian EH26 0PZ, UK.
Reid
H W
HW
Nettleton
P F
PF
McInnes
C J
CJ
Haig
D M
DM
D000818:Animals; D001706:Biopsy / Q000662:veterinary; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D004474:Ecthyma, Contagious / Q000276:immunology* / Q000473:pathology / Q000821:virology; D007150:Immunohistochemistry / Q000662:veterinary; D017403:In Situ Hybridization / Q000662:veterinary; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics; D009923:Orf virus / Q000254:growth & development / Q000276:immunology*; D015347:RNA Probes / Q000737:chemistry; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012756:Sheep; D017193:Skin Diseases, Viral / Q000276:immunology / Q000473:pathology / Q000662:veterinary* / Q000821:virology
D016207:Cytokines; D015347:RNA Probes; D012333:RNA, Messenger; D007371:Interferon-gamma