title: The viral sigma1 protein and glycoconjugates containing alpha2-3-linked sialic acid are involved in type 1 reovirus adherence to M cell apical surfaces.
abstract: Type 1 reoviruses invade the intestinal mucosa of mice by adhering selectively to M cells in the follicle-associated epithelium and then exploiting M cell transport activity. The purpose of this study was to identify the apical cell membrane component and viral protein that mediate the M cell adherence of these viruses. Virions and infectious subviral particles of reovirus type 1 Lang (T1L) adhered to rabbit M cells in Peyer's patch mucosal explants and to tissue sections in an overlay assay. Viral adherence was abolished by pretreatment of sections with periodate and in the presence of excess sialic acid or lectins MAL-I and MAL-II (which recognize complex oligosaccharides containing sialic acid linked alpha2-3 to galactose). The binding of T1L particles to polarized human intestinal (Caco-2(BBe)) cell monolayers was correlated with the presence of MAL-I and MAL-II binding sites, blocked by excess MAL-I and -II, and abolished by neuraminidase treatment. Other type 1 reovirus isolates exhibited MAL-II-sensitive binding to rabbit M cells and polarized Caco-2(BBe) cells, but type 2 or type 3 isolates including type 3 Dearing (T3D) did not. In assays using T1L-T3D reassortants and recoated viral cores containing T1L, T3D, or no sigma1 protein, MAL-II-sensitive binding to rabbit M cells and polarized Caco-2(BBe) cells was consistently associated with the T1L sigma1. MAL-II-recognized oligosaccharide epitopes are not restricted to M cells in vivo, but MAL-II immobilized on virus-sized microparticles bound only to the follicle-associated epithelium and M cells. The results suggest that selective binding of type 1 reoviruses to M cells in vivo involves interaction of the type 1 sigma1 protein with glycoconjugates containing alpha2-3-linked sialic acid that are accessible to viral particles only on M cell apical surfaces.
authors.affiliation: GI Cell Biology Laboratory, Enders 1220, Children's Hospital and Department of Pediatrics, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Helander
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Silvey
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Mantis
authors.forename: Amy B
authors.initials: AB
authors.lastname: Hutchings
authors.forename: Kartik
authors.initials: K
authors.lastname: Chandran
authors.forename: William T
authors.initials: WT
authors.lastname: Lucas
authors.forename: Max L
authors.initials: ML
authors.lastname: Nibert
authors.forename: Marian R
authors.initials: MR
authors.lastname: Neutra
mesh_terms: D000818:Animals; D001665:Binding Sites; D018938:Caco-2 Cells; D036022:Capsid Proteins / Q000737:chemistry* / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism / Q000821:virology; D016764:Cell Polarity; D002478:Cells, Cultured; D005260:Female; D006001:Glycoconjugates / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000821:virology*; D008561:Membrane Fusion; D051379:Mice; D008807:Mice, Inbred BALB C; D030102:Orthoreovirus, Mammalian / Q000472:pathogenicity / Q000502:physiology*; D010581:Peyer's Patches / Q000821:virology; D011817:Rabbits; D012794:Sialic Acids / Q000737:chemistry* / Q000378:metabolism
chemical_list: D036022:Capsid Proteins; D006001:Glycoconjugates; D012794:Sialic Acids; C031728:sigma 1 protein, reovirus