RT Journal Article SR Electronic(1) A1 Rijsbergen, Laurine C. A1 Rennick, Linda J. A1 Laksono, Brigitta M. A1 van Run, Peter R.W.A. A1 Kuiken, Thijs A1 Duprex, W. Paul A1 de Swart, Rik L. A1 de Vries, Rory D.YR 2020 T1 In vivo comparison of a laboratory-adapted and clinical-isolate-based recombinant human respiratory syncytial virus JF Journal of General Virology, VO 101 IS 10 SP 1037 OP 1046 DO https://doi.org/10.1099/jgv.0.001468 PB Microbiology Society, SN 1465-2099, AB Human respiratory syncytial virus (HRSV) is the leading cause of severe respiratory tract disease in infants. Most HRSV infections remain restricted to the upper respiratory tract (URT), but in a small percentage of patients the infection spreads to the lower respiratory tract, resulting in bronchiolitis or pneumonia. We have a limited understanding of HRSV pathogenesis and what factors determine disease severity, partly due to the widespread use of tissue-culture-adapted viruses. Here, we studied early viral dissemination and tropism of HRSV in cotton rats, BALB/cJ mice and C57BL/6 mice. We used a novel recombinant (r) strain based on a subgroup A clinical isolate (A11) expressing EGFP [rHRSVA11EGFP(5)]. A recombinant laboratory-adapted HRSV strain [rHRSVA2EGFP(5)] was used as a direct comparison. Our results show that rHRSVA11EGFP(5) replicated to higher viral titres than laboratory-adapted rHRSVA2EGFP(5) in the URT of cotton rats and mice. HRSV-infected cells were detected as early as 2 days post-inoculation in both species in the nasal septa and lungs. Infection was predominantly present in ciliated epithelial cells in cotton rats and in the olfactory mucosa of mice. In our opinion, this study highlights that the choice of virus strain is important when studying HRSV pathogenesis in vivo and demonstrates that A11 is a representative clinical-based virus. Additionally, we show critical differences in tropism and inflammation when comparing HRSV infection of cotton rats and mice., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/jgv.0.001468