Activation of sialoadhesin down-regulates the levels of innate antiviral cytokines in porcine alveolar macrophages in vitro.

•PRRSV infection inhibits innate antiviral response in PAMs.•PRRSV infection enhances the level of pSn in PAMs.•Activation of pSn inhibits innate antiviral response in PAMs.•pSn1, pSn2, pSn3, pSn4 and pSn5 domains of pSn mediate the inhibition of innate antiviral response in PAMs.