Abstract
Background
Almost all infants are infected with RSV by 2 years. 1–3 % of RSV-infected infants are hospitalised with severe disease. Reasons for susceptibility to severe disease remain obscure. We aimed to identify factors that might explain such susceptibility.
Methods
We generated well-differentiated primary nasal epithelial cell (WD-PNEC) cultures from infants with histories of severe or mild RSV disease. Following infection with RSV BT2a (clinical isolate), virus growth kinetics, cytopathogenesis, chemokines, and IL-29/IFNλ1 responses and differential gene expression were determined. In an exciting development, 1 differentially expressed gene, ptn, encodes pleiotrophin (PTN), which interacts with nucleolin (NCL), an RSV entry co-factor. The PTN antiviral activity was determined in BEAS-2B cells and WD-PBECs (where B=bronchial).
Results
Viral growth kinetics, cell tropism, IP-10/CXCL10, TRAIL and RANTES/CCL5 responses did not differ significantly between cohorts. However, apical cell sloughing and IL-29/IFNλ1 were diminished in severe WD-PNECs following infection, while expression of isg15, ifi6, irf9, duox2 and tap1 was also reduced. Interestingly, diminished ptn expression was evident in severe WD-PNECs, irrespective of RSV infection. Furthermore, pre-treatment with PTN blocked RSV infection in BEAS-2B cells and WD-PBECs, while neutralisation of PTN with either antibodies or siRNAs resulted in increased RSV replication.
Conclusions
Diminished apical cell sloughing and expression/secretion of IL-29/IFNλ1 and specific interferon stimulated genes in WD-PNECs were associated with severe RSV. Importantly, PTN was identified as a novel endogenously expressed RSV antiviral protein in human airway epithelium. Lower expression of PTN in paediatric airway epithelium may explain, in part, increased susceptibility to severe disease.
Almost all infants are infected with RSV by 2 years. 1–3 % of RSV-infected infants are hospitalised with severe disease. Reasons for susceptibility to severe disease remain obscure. We aimed to identify factors that might explain such susceptibility.
Methods
We generated well-differentiated primary nasal epithelial cell (WD-PNEC) cultures from infants with histories of severe or mild RSV disease. Following infection with RSV BT2a (clinical isolate), virus growth kinetics, cytopathogenesis, chemokines, and IL-29/IFNλ1 responses and differential gene expression were determined. In an exciting development, 1 differentially expressed gene, ptn, encodes pleiotrophin (PTN), which interacts with nucleolin (NCL), an RSV entry co-factor. The PTN antiviral activity was determined in BEAS-2B cells and WD-PBECs (where B=bronchial).
Results
Viral growth kinetics, cell tropism, IP-10/CXCL10, TRAIL and RANTES/CCL5 responses did not differ significantly between cohorts. However, apical cell sloughing and IL-29/IFNλ1 were diminished in severe WD-PNECs following infection, while expression of isg15, ifi6, irf9, duox2 and tap1 was also reduced. Interestingly, diminished ptn expression was evident in severe WD-PNECs, irrespective of RSV infection. Furthermore, pre-treatment with PTN blocked RSV infection in BEAS-2B cells and WD-PBECs, while neutralisation of PTN with either antibodies or siRNAs resulted in increased RSV replication.
Conclusions
Diminished apical cell sloughing and expression/secretion of IL-29/IFNλ1 and specific interferon stimulated genes in WD-PNECs were associated with severe RSV. Importantly, PTN was identified as a novel endogenously expressed RSV antiviral protein in human airway epithelium. Lower expression of PTN in paediatric airway epithelium may explain, in part, increased susceptibility to severe disease.
Original language | English |
---|---|
Pages (from-to) | 837 |
Number of pages | 1 |
Journal | Access Microbiology |
Volume | 1 |
Issue number | 1A |
DOIs | |
Publication status | Published - 08 Apr 2019 |
Event | Microbiology Society Annual Conference 2019 - Belfast, Belfast, United Kingdom Duration: 08 Apr 2019 → 11 Apr 2019 |