Avibacterium paragallinarum (Av. Paragallinarum) infection causes infectious coryza, which is a widespread and serious respiratory disease in chickens. Although the HutZ protein has been linked to heme utilization and virulence in various pathogens, a specific role in host-pathogen interactions during Av. paragallinarum infection remains unclear. In this study, to investigate host immune responses and the regulatory role of HutZ following Av. paragallinarum infection, we performed the transcriptomic profiles of avian macrophage HD11 following wild and HutZ mutant of Av. paragallinarum infection using RNA-seq, respectively. The differentially expressed genes (DEGs) in the HD11 macrophages between the two groups were identified. Compared with the uninfected group, more DEGs involved in signaling pathways and cellular functions were identified in the infected groups. Our results revealed extensive transcriptional changes following infection, with both bacterial strains activating core immune pathways including PI3K-Akt and MAPK signaling. Notably, the HutZ mutant elicited stronger activation of pattern recognition receptor pathways such as Toll-like, NOD-like, and RIG-I-like signaling, suggesting that HutZ may help the pathogen evade host immune detection. This work provides novel insights into the immunomodulatory role of HutZ and offers a foundation for developing targeted interventions against Av. paragallinarum.

To Cite This Article: Li G, Zhang Q, Li X, Xiu M, Sun Y, Xu T, Xu F and Sun H 2025. Transcriptomic profiling of avian macrophages HD11 reveals the immunomodulatory role of HutZ in Avibacterium paragallinarum infection. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2025.274