African swine fever virus L11L interferes with antiviral responses by targeting the IRF3 and PKR.

The African Swine Fever Virus (ASFV) is a large, complex DNA virus that infects wild boars and domestic pigs. It causes African Swine Fever (ASF), an intense and often fatal disease with 100% fatality rate. After infection, ASFV employs specific viral proteins to enhance pathogenicity. However, the functions of many of these proteins remain unknown. This study investigated the molecular mechanism by which ASFV L11L evades type I interferon (IFN) pathway and protein kinase R (PKR)-mediated antiviral responses. Interestingly, we found that L11L interacts with interferon regulatory factor 3 (IRF3), specifically with the S396 and S398 amino acids, leading to the inhibition of the phosphorylation of IRF3 by Tank-binding kinase 1 (TBK1). Consequently, this interaction impedes IRF3 dimerization, nuclear translocation and subsequent IFN-β production. Besides, L11L inhibits the dimerization of PKR by targeting its K196 amino acid, preventing the phosphorylation of its substrate, eukaryotic initiation factor-2 (eIF2), to promote viral replication. Altogether, these novel findings conclude that L11L suppresses antiviral immunity and promotes viral replication, implying the identification of a novel target for the advancement of live-attenuated vaccines against ASF.