1310. Respiratory Syncytial Virus Plaque Morphology as It Relates to RSV Strain, Viral Load, and Disease Severity in Children
Session: Poster Abstract Session: Viral Immunology and Pathogenesis
Saturday, October 22, 2011
Room: Poster Hall B1
Handouts
  • RSV Plaque Morphology Poster.pdf (34.3 MB)
  • Background: RSV plaque size and morphology in human cell lines is a marker for in vitro growth capability, and have traditionally been used to select pre-attenuation candidates for live viral vaccines because of the view that small plaque sizes produce less severe disease.  Therefore, we evaluated the relationships between plaque morphology of passage-0 clinical isolates, RSV strain, viral load, and disease severity in children. 

    Methods: Respiratory secretions were collected from 160 RSV-infected children (<2yo) on day of enrollment, and cultured in quantitative plaque assays without freezing. Strain was defined by N-gene PCR.  Viral load was determined by qPCR and plaque assay.  Disease severity was determined by ± hospitalization, length of stay, ± respiratory failure.  Plaque morphology was determined by investigators blinded to patients’ outcome, strain, and viral load.

    Results: Similar plaque morphologies (size, % capped, and invasiveness) were seen between viruses collected at the same time from upper and lower respiratory tracts of the same patient.  However, significant differences in plaque morphology were observed between RSV strains.  RSV A had larger plaques (Mean Δ Size A vs B = 66.59 ± 28.79; p=0.0085), and RSV B had a greater % of capped plaques than RSV A (Mean Δ %Capped A vs B = 26.07 ± 5.695; p<0.0001).  No correlation was found between plaque morphology and disease severity (p all >0.05).  Additionally, no correlation was found between plaque morphology and viral load by q culture or qPCR.

    Conclusion: RSV plaque morphology does not differ within individuals, but plaque morphology does differ significantly between strains.  No correlation was observed between plaque characteristics and disease severity.  This further suggests that plaque morphology is an unreliable selection method for pre-attenuated live viral vaccines.  In vitro viral growth characteristics of plaque morphology do not appear to have a major influence on disease severity.


    Subject Category: V. Virology including clinical and basic studies of viral infections, including hepatitis

    Ryan Murphy, BS & BA, Sirshendu Majumdar, BS, April Sullivan, Lisa Harrison, MLT, Jody Aitkin, RN and John DeVincenzo, MD, Pediatrics, University of Tennessee Health Science Center, Memphis, TN

    Disclosures:

    R. Murphy, None

    S. Majumdar, None

    A. Sullivan, None

    L. Harrison, None

    J. Aitkin, None

    J. DeVincenzo, None

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.