Defective interfering particles of parainfluenza virus subtype 5 and interferon induction

Interferon inducers;Parainfluenza viruses

Short, John A. L. ; Randall, R. E. ; Randall, R. E.

University:University of St Andrews

Department:Biology (School of)

关键词: Interferon inducers;    Parainfluenza viruses;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/7036/JohnALShortPhDThesis.pdf?sequence=3&isAllowed=y

来源: DR-NTU

【 摘 要 】

The innate immune response is the first line of defence against virus infection. Cells containa diverse array of pathogen recognition receptors (PRRs) that are able to recognise multiplepathogen associated molecular patterns (PAMPS) that present themselves during virusinfection. The RIG-I (Retinoic acid inducible–gene-I) and MDA5 (melanoma differentiation-associated gene 5) PRRs detect specific viral RNA ligands and subsequently induce theexpression of the cytokine Interferon-β (IFN-β). IFN-β is secreted, acting on the infected celland neighbouring uninfected cells to generate an antiviral state that is hostile to virustranscription, replication and dissemination, whilst also orchestrating adaptive immuneresponses. Given IFN-β's crucial cellular antiviral role, understanding its induction is of greatimportance to developing future antiviral drugs and vaccine strategies.Using A549 reporter cells in which GFP expression is under the control of the IFN-β promoter,we show that there is a heterocellular response to parainfluenza virus 5 (PIV5) and infectionwith other negative sense RNA viruses. Only a limited number of infected cells areresponsible for IFN-β induction. Using PIV5 as a model, this thesis addresses the nature ofthe PAMPs that are responsible for inducing IFN-β following PIV5 infection. The previouswork has shown that PIV5 Defective Interfering particle (DI) rich virus preparations acted as abetter inducer of IFN-β compared to DI poor stocks. DIs are incomplete virus genomesproduced during wild-type virus replication as a result of errors in the viral polymerase. Toinvestigate this further, A549 Naïve, MDA5/RIG-I/LGP2 Knock down reporter cells wereinfected with PIV5 W3 at a low MOI to examine the inverse correlation of NP and GFP of DIsgenerated during virus replication and not from the initial infection. GFP+ve cells were cellsorted, and using QPCR it was found that cells that have the IFN-β promoter activatedcontain large amounts of DIs relative to GFP-ve cells. This data supports the Randall group’sfindings that DIs generated during errors of wild-type replication by the viral RNA polymeraseare the primary PAMPs that induce of IFN-β, as opposed to PAMPs being generated duringnormal wild-type virus replication.