Figure 4From: Antiviral activity of ISG15 against classical swine fever virus replication in porcine alveolar macrophages via inhibition of autophagy by ISGylating BECN1ISGylation is involved in the antiviral activity of ISG15 against CSFV.A Expression of ISGylated protein was detected by Western blot with an anti-ISG15 antibody. B, C Effects of ISGylation on CSFV replication. PAMs B and shISG15 cells C were transfected with 3.1, 3.1-ISG15AA, and 3.1-ISG15GG plasmid followed by CSFV infection for another 24 h (MOI = 1). CSFV replication was quantified by RT-qPCR and IFA, respectively. D, E PAMs with stable knockdown of USP18 were constructed by lentiviral transduction. D Expression of USP18 protein was detected by Western blot. E Cell viability with stable knockdown of USP18. ShN and shUSP18 cells were pretreated with IFN-α and then infected with CSFV (MOI = 1). F CSFV replication was quantified by RT-qPCR and IFA, respectively. G Expression of ISGylated protein was detected by Western blot with an anti-ISG15 antibody. HMx1 expression was analyzed by RT-qPCR. Data (B, C, E, F, and H) represent the mean ± SD of three independent experiments and were measured in technical duplicate. Comparisons between groups were calculated using Student’s t-test. **P < 0.01; ***P < 0.001Back to article page