title: A homolog of interleukin-10 is encoded by the poxvirus orf virus.
abstract: A gene encoding a polypeptide with homology to interleukin-10 (IL-10) has been discovered in the genome of orf virus (OV) strain NZ2, a parapoxvirus that infects sheep, goats, and humans. The predicted polypeptide sequence shows high levels of amino acid identity to IL-10 of sheep (80%), cattle (75%), humans (67%), and mice (64%), as well as IL-10-like proteins of Epstein-Barr virus (63%) and equine herpesvirus (67%). The C-terminal region, comprising two-thirds of the OV protein, is identical to ovine IL-10, which suggests that this gene has been captured from its host sheep during the evolution of OV. The IL-10-like gene is transcribed early. Conditioned medium from COS cells transfected with a eukaryotic expression vector containing the OV IL-10-like gene showed the same biological activity as ovine IL-10 in a murine thymocyte proliferation assay. OV IL-10 is likely to be important in immune evasion by OV, since IL-10 is a multifunctional cytokine that has inhibitory effects on nonspecific immunity and Th1 effector function.
authors.affiliation: Health Research Council Virus Research Unit and University of Otago Centre for Gene Research, University of Otago, Dunedin, New Zealand. steve@sanger.otago.ac.nz
authors.forename: S B
authors.initials: SB
authors.lastname: Fleming
authors.forename: C A
authors.initials: CA
authors.lastname: McCaughan
authors.forename: A E
authors.initials: AE
authors.lastname: Andrews
authors.forename: A D
authors.initials: AD
authors.lastname: Nash
authors.forename: A A
authors.initials: AA
authors.lastname: Mercer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D004279:DNA, Viral / Q000235:genetics; D015870:Gene Expression; D005814:Genes, Viral; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics*; D008213:Lymphocyte Activation; D051379:Mice; D008969:Molecular Sequence Data; D009923:Orf virus / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012756:Sheep; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D004279:DNA, Viral; D012333:RNA, Messenger; D012367:RNA, Viral; D015678:Viral Structural Proteins; D016753:Interleukin-10