Transcriptome Analysis of Differences in the Infection of African Swine Fever Virus in ZMAC-4 and PAM Cells: Unveiling the Potential Mechanisms of the Virus in Passaged Cells

African swine fever (ASF), caused by the African swine fever virus (ASFV), is a highly contagious hemorrhagic disease with severe socioeconomic impacts on the global swine industry. Despite extensive efforts to develop effective control strategies, the lack of efficient in vitro models remains a critical barrier. A key challenge lies in the restricted tropism of ASFV; it robustly infects primary porcine alveolar macrophages (PAMs), and exhibits replicates poorly in most passaged cell lines, hindering mechanistic studies and antiviral development. To address this limitation, we conducted a comparative transcriptomic analysis of ASFV-infected PAMs (primary cells) and ZMAC-4 cells (passaged macrophage line) during early infection. Our findings revealed significant differences in viral susceptibility and host responses between the two cell types. Transcriptome profiling identified divergent activation of critical pathways: ZMAC-4 cells predominantly upregulated oxidative stress-related pathways, whereas PAMs exhibited robust cytokine signaling and immune activation. Further analysis of differentially expressed genes (DEGs) through knockdown and overexpression experiments showed that junctophilin-4 (JPH4 ) and cytochrome P450 1A1 (CYP1A1) were two potential host restriction factors. This study delineates early host-virus dynamics in ASFV-permissive versus semi-permissive cells, providing mechanistic insights into tropism and highlighting JPH4/CYP1A1 as novel targets for antiviral strategies. These findings lay a foundation for the rational design of antiviral strategies and improved vaccine platforms, thus addressing a critical gap in ASF research.Keywords: African swine fever virus; viral replication; ZMAC-4 cells; PAM cells; transcriptomic analysis; JPH4/CYP1A1