Participation of interferon type I during canine parvovirus infection

Canine parvovirus (CPV) is a single-stranded DNA virus that causes severe and fatal gastrointestinal diseases in dogs. CPV has developed several strategies to evade innate immune response mediated by type I interferons (IFN-I) to achieve a successful infection. The aim of this work was to evaluate the capability of CVP-2c to evade the IFN-I mediated response in infected cells. To establish the role of this response, the gene expression of interferon β (IFNβ), IFIT1, IFIT3, MAVS, and STING were estimated in MDCK cells infected with CPV-2c. Viral replication and gene expression was evaluated by quantitative PCR, also, a treatment with IFN-I (interferon omega) was included to confirm the role of IFN-I during CPV infection. The results revealed that CPV-2c infection stimulates the expression of IFNβ moderately, in these cells. Due to low IFNβ induction, the IFIT1 and IFIT3 expression were also low, and therefore CPV-2c was able to replicate in these cells. However, when the cells were treated with exogenous IFN-I, the IFNβ expression was higher, leading to an increased gene expression of IFIT1 and IFIT3, responsible for antiviral control. The overexpression of these proteins reduced the expression of NS1 and VP2 viral genes and hence viral replication. MAVS and STING expression on infected cells showed a mild increase compared to IFNβ, suggesting that the viral infection could partially modify its expression. All results obtained in this study showed that during CPV-2c infection in MDCK cells, the IFNβ expression was altered since this cytokine is one of the most critical factors for the control and inhibition of viral replication.