Human metapneumovirus: interferon sensitivity and production in airway epithelial cells
Abstract number: P1946
Scagnolari C., Selvaggi C., Carbone T., Soldà A., Spano L., Di Marco P., Maggi F., Riva E., Pierangeli A., Antonelli G.
Objectives: Actually very little is known about Human Metapneumovirus (hMPV) pathogenesis and the activation of innate immune response triggered by infection.
The aim of this study was to investigated whether hMPV is sensitive to the antiviral activity of interferon (IFN) b, leukocyte IFN a and several IFN a subtypes. The sensitivity of hMPV was compared with that of the vesicular stomatitis virus (VSV) which is known to be highly sensitive to the action of all types of IFN. In addition we evaluated the transcript expression of IFN a subtypes after hMPV infection.
Methods: Antiviral effect of IFNs against hMPV or VSV replication in human laryngeal carcinoma Hep-2 cells were analysed by yield reduction assay. The transcriptional induction of the IFN a subtypes in Hep-2 infected with hMPV or transfected with PolyIC were investigated by real time reverse transcript-PCR.
Results: Results indicated that IFNs showed substantially different capacities for inhibiting the hMPV yield in Hep-2 cells. In particular in Hep-2 cells pre-treated with IFNs and infected with hMPV for 24 hours, leukocyte IFN a were less potent than IFN b. Among IFN a subtypes investigated, IFN5, IFN6, IFN8 and IFN10 were the most active while IFN17 and IFN21 were the least potent. IFN1, IFN2b, IFN7, IFN14 had comparable intermediate activity. In addition results indicate that the IC50 values of the different type I IFNs preparations against VSV were significantly lower compared to those against hMPV. Furthermore we found that, over a timecourse of 48 hours of infection, lower levels of IFN a subtypes were transcribed in Hep-2 cells infected with hMPV in contrast with those induced by Poly IC.
Conclusion: This study provides evidence that hMPV are partially resistant to the antiviral activity of IFN type I, although some IFN a subtypes appear to be more active against hMPV than others. Furthermore hMPV appears to be a weak inducers of IFN type I too. The implications of these observations in terms of hMPV pathogenesis is now under study.
|Session name:||Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Vienna, Austria, 10 - 13 April 2010|
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