title: Respiratory Syncytial Virus Attachment Glycoprotein Contribution to Infection Depends on the Specific Fusion Protein.
abstract: Human respiratory syncytial virus (RSV) is an important pathogen causing acute lower respiratory tract disease in children. The RSV attachment glycoprotein (G) is not required for infection, as G-null RSV replicates efficiently in several cell lines. Our laboratory previously reported that the viral fusion (F) protein is a determinant of strain-dependent pathogenesis. Here, we hypothesized that virus dependence on G is determined by the strain specificity of F. We generated recombinant viruses expressing G and F, or null for G, from the laboratory A2 strain (Katushka RSV-A2GA2F [kRSV-A2GA2F] and kRSV-GstopA2F) or the clinical isolate A2001/2-20 (kRSV-2-20G2-20F and kRSV-Gstop2-20F). We quantified the virus cell binding, entry kinetics, infectivity, and growth kinetics of these four recombinant viruses in vitro. RSV expressing the 2-20 G protein exhibited the greatest binding activity. Compared to the parental viruses expressing G and F, removal of 2-20 G had more deleterious effects on binding, entry, infectivity, and growth than removal of A2 G. Overall, RSV expressing 2-20 F had a high dependence on G for binding, entry, and infection.
  
  
  OBJECTIVE
  RSV is the leading cause of childhood acute respiratory disease requiring hospitalization. As with other paramyxoviruses, two major RSV surface viral glycoproteins, the G attachment protein and the F fusion protein, mediate virus binding and subsequent membrane fusion, respectively. Previous work on the RSV A2 prototypical strain demonstrated that the G protein is functionally dispensable for in vitro replication. This is in contrast to other paramyxoviruses that require attachment protein function as a prerequisite for fusion. We reevaluated this requirement for RSV using G and F proteins from clinical isolate 2-20. Compared to the laboratory A2 strain, the G protein from 2-20 had greater contributions to virus binding, entry, infectivity, and in vitro growth kinetics. Thus, the clinical isolate 2-20 F protein function depended more on its G protein, suggesting that RSV has a higher dependence on G than previously thought.
authors.affiliation: Department of Pediatrics, Emory University of School of Medicine, Atlanta, Georgia, USA Children's Healthcare of Atlanta, Atlanta, Georgia, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Meng
authors.affiliation: Department of Pediatrics, Emory University of School of Medicine, Atlanta, Georgia, USA Children's Healthcare of Atlanta, Atlanta, Georgia, USA.
authors.forename: Anne L
authors.initials: AL
authors.lastname: Hotard
authors.affiliation: Department of Pediatrics, Emory University of School of Medicine, Atlanta, Georgia, USA Children's Healthcare of Atlanta, Atlanta, Georgia, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Currier
authors.affiliation: Department of Pediatrics, Emory University of School of Medicine, Atlanta, Georgia, USA Children's Healthcare of Atlanta, Atlanta, Georgia, USA.
authors.forename: Sujin
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Pediatrics, Emory University of School of Medicine, Atlanta, Georgia, USA Children's Healthcare of Atlanta, Atlanta, Georgia, USA.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Stobart
authors.affiliation: Department of Pediatrics, Emory University of School of Medicine, Atlanta, Georgia, USA Children's Healthcare of Atlanta, Atlanta, Georgia, USA martin.moore@emory.edu.
authors.forename: Martin L
authors.initials: ML
authors.lastname: Moore
mesh_terms: D002460:Cell Line; D002675:Child, Preschool; D006801:Humans; D018357:Respiratory Syncytial Virus Infections / Q000821:virology; D018113:Respiratory Syncytial Virus, Human / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*; D014759:Viral Envelope Proteins / Q000378:metabolism*; D014760:Viral Fusion Proteins / Q000378:metabolism*; D053585:Virus Attachment; D053586:Virus Internalization
chemical_list: C526850:F protein, human respiratory syncytial virus; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; C116204:attachment protein G