Chloroquine Phosphate Targets the MAPK-ERK Pathway to Inhibit ASFV SY-1 Replication In Vitro

African swine fever virus (ASFV) can infect domestic pigs and wild boars, cause a highly lethal disease and substantial economic losses on the global swine industry. Due to the virus `s large genome and high mutation frequency, no effective vaccine has been put into use, making the devel-opment of antiviral drugs particularly urgent. In this study, using multiple experimental methods including RT-qPCR, western blotting, and HAD50, we confirmed that chloroquine phosphate (CQP) exerts a significant in-hibitory effect on the ASFV SY-1 strain. Time-course experiments further showed that CQP exerts its antiviral effect mainly in the late stage of viral infection (after 6 hours post-infection).Based on transcriptome sequencing and KEGG pathway enrichment analysis, we found that CQP treatment significantly affects multiple sig-naling pathways, including the cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, TNF signaling pathway and so on. Western blotting results further indicated that CQP can specifically inhibit the phosphorylation of ERK, moreover, treatment with the ERK agonist C16-PAF can reverse the inhibitory effect induced by CQP, thereby veri-fying the key role of this pathway in the antiviral mechanism of CQP.This study reveals the molecular mechanism of CQP effectively inhib-its ASFV replication by suppressing the MAPK-ERK signaling pathway., providing important theoretical basis and technical support for the devel-opment of antiviral strategies targeting ASFV.