Deciphering Immune Modulation in Chickens Co-Infected with ALV-J and CIAV: A Transcriptomic Approach

Viral co-infections pose significant challenges, causing substantial economic losses worldwide in the poultry industry. Among these, avian lLeukosis virus subgroup J (ALV-J) and chicken infectious anemia virus (CIAV) are particularly concerning, as they frequently lead to co-infections in chickens, further compromising their immune defenses, increasing susceptibility to secondary infections and diminishing vaccine efficacy. While our previous studies have examined the pathogenicity and immunosuppressive effects of these co-infections in vitro and in vivo, the key genes and molecular pathways involved remain largely unexplored. This study investigates the synergistic effects of co-infection with ALV-J and CIAV through comprehensive transcriptome analysis using high-throughput sequencing. We identified 1007 differentially expressed mRNAs (DEmRNAs) and 62 differentially expressed miRNAs (DEmiRNAs) associated with the synergistic activation effects of co-infection, along with 331 DEmRNAs and 62 DEmiRNAs linked to specific activation processes. Notably, the immune suppression observed in co-infected chickens may be influenced by the enhanced utilization of reactive oxygen species (ROS) and oxidative stress pathways, which impact host immune responses. Furthermore, co-infection appears to employ distinct immune evasion strategies through the modulation of rRNA metabolism, differing from single infections. These insights provide a deeper understanding of the molecular mechanisms underlying immune suppression during viral co-infections and help develop targeted therapies and improve disease control in poultry, reducing economic losses.