Evans, D.

Williams, David

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803Binding of decay accelerating factor by human echovirus 6 is a stable phenotype required forRD cell infectionOavid T. Williams and Oavid J. EvansDivision of Virology, Faculty of Biomedical and Life Sciences, University of Glasgow, Church Street,Glasgow, G11 5JR, UK. E-mail: d.williams@vir.gla.ac.ukThe prototype strain of human echovirus EV 6 (EV6) binds the complement regulator decayaccelerating factor (OAF) with low affinity and, unlike other OAF-binding EVs, cannot haemagglutinate(HA) red blood cells. Binding to the surface of human rhabdomyosarcoma (RO) cells by EV6 isprimarily mediated by the glycosaminoglycan heparan sulfate (HS). By passaging this virus in thepresence of soluble heparin, a highly sulphated form of HS, we have generated HS binding variantviruses (HSvarVs) that can mediate haemagglutination via OAF; HA of HSvaVs could be inhibited withvery low concentrations of Pischia-expressed soluble OAF. Affinity chromatography using heparinagarose columns and binding-inhibition assays with soluble heparin demonstrated that these variantsretained their HS-binding phenotype at levels indistinguishable from the wildtype virus. Sequenceanalysis of the region of viral RNA encoding the capsid proteins revealed single amino acid changes inthe EF-Ioop of VP2 for each of the HSvaVs, indicating that molecular determinants for OAF-binding arelikely to reside in this region. An additional HSvaV, which demonstrated no detectable HS-bindingphenotype, was found to have an additional charged amino acid change in the DE loop of VP1, which,when modelled on the 3D structure of the closely-related EV11, was found to form a ring of chargedresidues surrounding the pentameric apex. Interestingly, cell protection assays with an anti-DAFpolyclonal antibody and/or soluble heparin revealed that, regardless of their HS binding phenotype,infection by prototype or variant viruses was completely blocked only in the presence of antibody,indicating a requirement of OAF for infection by these viruses. Furthermore, these viruses were shownto associate with OAF-containing lipid rafts at equivalent levels, supporting the conclusion that, whilethe HS-binding phenotype of these viruses may be variable, that of DAF-binding is stable.B - Virus Structure and Entry

Binding of decay-accelerating factor by human echovirus 6 is a stable phenotype required for RD cell infection

https://espace.curtin.edu.au/bitstream/20.500.11937/45225/2/132235_13906_Europic2005_Williams_1.pdf

Binding of decay-accelerating factor by human echovirus 6 is a stable phenotype required for RD cell infection

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