title: Positively charged residues at the five-fold symmetry axis of cell culture-adapted foot-and-mouth disease virus permit novel receptor interactions.
abstract: Field isolates of foot-and-mouth disease virus (FMDV) have a restricted cell tropism which is limited by the need for certain RGD-dependent integrin receptors. In contrast, cell culture-adapted viruses use heparan sulfate (HS) or other unidentified molecules as receptors to initiate infection. Here, we report several novel findings resulting from cell culture adaptation of FMDV. In cell culture, a virus with the capsid of the A/Turkey/2/2006 field isolate gained the ability to infect CHO and HS-deficient CHO cells as a result of a single glutamine (Q)-to-lysine (K) substitution at VP1-110 (VP1-(Q)110(K)). Using site-directed mutagenesis, the introduction of lysine at this same site also resulted in an acquired ability to infect CHO cells by type O and Asia-1 FMDV. However, this ability appeared to require a second positively charged residue at VP1-109. CHO cells express two RGD-binding integrins (α5β1 and αvβ5) that, although not used by FMDV, have the potential to be used as receptors; however, viruses with the VP1-(Q)110(K) substitution did not use these integrins. In contrast, the VP1-(Q)110(K) substitution appeared to result in enhanced interactions with αvβ6, which allowed a virus with KGE in place of the normal RGD integrin-binding motif to use αvβ6 as a receptor. Thus, our results confirmed the existence of nonintegrin, non-HS receptors for FMDV on CHO cells and revealed a novel, non-RGD-dependent use of αvβ6 as a receptor. The introduction of lysine at VP1-110 may allow for cell culture adaptation of FMDV by design, which may prove useful for vaccine manufacture when cell culture adaptation proves intractable.
authors.affiliation: Pirbright Institute, Pirbright, Surrey, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Berryman
authors.forename: Stuart
authors.initials: S
authors.lastname: Clark
authors.forename: Naresh K
authors.initials: NK
authors.lastname: Kakker
authors.forename: Rhiannon
authors.initials: R
authors.lastname: Silk
authors.forename: Julian
authors.initials: J
authors.lastname: Seago
authors.forename: Jemma
authors.initials: J
authors.lastname: Wadsworth
authors.forename: Kyle
authors.initials: K
authors.lastname: Chamberlain
authors.forename: Nick J
authors.initials: NJ
authors.lastname: Knowles
authors.forename: Terry
authors.initials: T
authors.lastname: Jackson
mesh_terms: D000220:Adaptation, Biological; D000818:Animals; D016466:CHO Cells; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D004252:DNA Mutational Analysis; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000502:physiology*; D016297:Mutagenesis, Site-Directed; D011991:Receptors, Virus / Q000378:metabolism*; D012692:Serial Passage; D056189:Viral Tropism
chemical_list: D036022:Capsid Proteins; D011991:Receptors, Virus