A single amino acid in the F2 subunit of respiratory syncytial virus fusion protein alters growth and fusogenicity

• Published in: Journal of general virology Vol. 94; no. 12; pp. 2627 - 2635
• Main Authors: Lawlor, Heather A., Schickli, Jeanne H., Tang, Roderick S.
• Format: Journal Article
• Language: English
• Published: England Society for General Microbiology 01.12.2013
• Subjects: Animal; Animals; Chlorocebus aethiops; Cytopathogenic Effect, Viral; Giant Cells - physiology; Humans; Models, Molecular; Mutation; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Respiratory syncytial virus; Respiratory Syncytial Virus Infections - virology; Respiratory Syncytial Virus, Human - genetics; Respiratory Syncytial Virus, Human - growth & development; Respiratory Syncytial Virus, Human - pathogenicity; Vero Cells; Viral Fusion Proteins - chemistry; Viral Fusion Proteins - genetics; Viral Fusion Proteins - metabolism
• ISSN: 0022-1317; 1465-2099; 1465-2099
• DOI: 10.1099/vir.0.055368-0

Respiratory syncytial virus (RSV) causes severe lower respiratory tract infection in children, especially in infants less than 1 year of age. There are currently no licensed vaccines against RSV. rA2ΔM2-2 is a promising live-attenuated vaccine candidate that is currently being evaluated in the clinic. Attenuation of rA2ΔM2-2 is achieved by a single deletion of the M2-2 gene, which disrupts the balance between viral transcription and replication. Whilst performing a manufacturing feasibility study in a serum-free adapted Vero cell line, differences in growth kinetics and cytopathic effect (CPE) were identified between two rA2ΔM2-2 vaccine candidates. Comparative sequence analysis identified four amino acid differences between the two vaccine viruses. Recombinant rA2ΔM2-2 viruses carrying each of the four amino acid differences identified a K66E mutation in the F 2 fragment of the fusion (F) protein as the cause of the growth and CPE differences. Syncytium-formation experiments with RSV F protein carrying mutations at aa 66 suggested that a change in charge at this residue within the F 2 fragment can have a significant impact on fusion.