Ligation of porcine Fc gamma receptor I inhibits levels of antiviral cytokine in response to PRRSV infection in vitro

PRRSV infection ADE facilitates the attachment and internalization of the virus onto macrophages through Fc receptor-mediated endocytosis. Fc gamma RI is the activating receptor with a tyrosine-based activating motif (ITAM) in its cytoplasmic tail, where up-regulates phagocytosis. However, porcine Fc gamma RI's role in the antiviral immune response to PRRSV infection has not been studied. In this study, our results indicated that selective activation of porcine Fc gamma RI in PAM cells down-regulated significantly mRNA levels of IFN-alpha and TNF-alpha post-pretreatment, suggesting that porcine Fc gamma RI signal can inhibit the innate antiviral response of host cells. PRRSV infection assay mediated by Fc gamma RI indicated that selective activation of porcine Fc gamma RI in PAM cells inhibited significantly mRNA levels of antiviral cytokine (IFN-alpha and TNF-alpha) in response to PRRSV infection, suggesting that Fc gamma RI ligation can inhibit the antiviral immune response to PRRSV infection. (C) 2013 Elsevier B.V. All rights reserved.