|Kehrli Jr, Marcus|
Submitted to: Viral Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/24/2009
Publication Date: 6/20/2009
Citation: Brockmeier, S., Lager, K.M., Grubman, M.J., Brough, D.E., Ettyreddy, D., Sacco, R.E., Gauger, P.C., Loving, C.L., Vorwald, A.C., Kehrli Jr, M.E., Lehmkuhl, H.D. 2009. Adenovirus-Mediated Expression of Interferon-Alpha Delays Viral Replication and Reduces Disease Signs in Swine Challenged with Porcine Reproductive and Respiratory Syndrome Virus. Viral Immunology. 22(3):173-180. Interpretive Summary: In this study, pigs were given a harmless adenovirus that was engineered to deliver interferon, which is an antiviral substance that the body naturally produces, and then challenged with porcine reproductive and respiratory syndrome virus (PRRSV) to determine whether the presence of interferon would decrease viral replication and/or disease. The adenovirus was successful in increasing the level of interferon in the pigs for several days. The presence of the interferon resulted in lower fevers, decreased pneumonia, and delayed the detection of virus in pigs challenged with PRRSV as compared to pigs not given the adenovirus and challenged with PRRSV. These results indicate that interferon can have protective effects if present during the time of infection with PRRSV.
Technical Abstract: In this study, pigs were injected with a nonreplicating human adenovirus type 5 vector expressing porcine interferon-alpha (Ad5-pIFNa) and then challenged with porcine reproductive and respiratory syndrome virus (PRRSV) to determine whether the presence of increased levels of IFNa would decrease viral replication and/or disease. Groups of 10 pigs each were inoculated with Ad5-pIFNa and not challenged, Ad5-pIFNa and challenged with PRRSV 1 day later, or inoculated with the same adenovirus that does not express IFNa (Ad5-null) and challenged 1 day later with PRRSV. IFNa levels in all pigs inoculated with the Ad5-pIFNa were elevated the day of challenge (1 day after inoculation) but were undetectable by 3 days after inoculation in the pigs that were not challenged with PRRSV. Pigs inoculated with Ad5-pIFNa and challenged with PRRSV had lower febrile responses, decreased percentage of lung involvement at 10 days post infection, delayed viremia and antibody response, and higher serum IFNa levels as a result of PRRSV infection, as compared to pigs inoculated with Ad5-null and challenged with PRRSV. These results indicate that interferon-alpha can have protective effects if present during the time of infection with PRRSV.