title: Rabbit CD200R binds host CD200 but not CD200-like proteins from poxviruses.
abstract: CD200 is a widely distributed membrane protein that gives inhibitory signals through its receptor (CD200R) on myeloid cells. CD200 has been acquired by herpesviruses where it has been shown to interact with host CD200R and downmodulate the immune system. It has been hypothesized that poxviruses have acquired CD200; but the potential orthologues show less similarity to their hosts. Myxoma virus M141 protein is a potential CD200 orthologue with a potent immune modulatory function in rabbits. Here, we characterized the rabbit CD200, CD200R and tested the CD200-like sequences for binding CD200R. No binding could be detected using soluble recombinant proteins, full length protein expressed on cells or myxoma virus infected cells. Finally, using knockdown models, we showed that the inhibitory effect of M141 on RAW 264.7 cells upon myxoma virus infection is not due to CD200R. We conclude that the rabbit poxvirus CD200-like proteins cause immunomodulation without utilizing CD200R.
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK. Electronic address: munir.akkaya@nih.gov.
authors.forename: Munir
authors.initials: M
authors.lastname: Akkaya
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
authors.forename: Lai-Shan
authors.initials: LS
authors.lastname: Kwong
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
authors.forename: Erdem
authors.initials: E
authors.lastname: Akkaya
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
authors.forename: Deborah
authors.initials: D
authors.lastname: Hatherley
authors.affiliation: Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
authors.forename: A Neil
authors.initials: AN
authors.lastname: Barclay
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D002460:Cell Line; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D009233:Myxoma virus / Q000502:physiology*; D011485:Protein Binding; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C501251:M141R protein, myxoma virus; D011956:Receptors, Cell Surface; D014764:Viral Proteins; C042739:antigens, CD200
keywords: CD200; CD200R; M141; Myxoma virus; Poxviruses