Screening of Optimal CpG-Oligodeoxynucleotide for Anti-Inflammatory Responses in the Avian Macrophage Cell Line HD11

CpG-oligodeoxynucleotides ( CPG-ODNS: ) have been shown to possess immunostimulatory features in both mammals and birds. However, compared to their proinflammatory effects, little is known about the anti-inflammatory responses triggered by CpG-ODN in avian cells. Hence, in this study, the anti-inflammatory response in the chicken macrophage cell line HD11 was characterized under stimulation with five types of CpG-ODNs: CpG-A(1585), CpG-A(D35), CpG-B(1555), CpG-B(K3), and CpG-C(2395). Single-stimulus of CpG-B(1555), CpG-B(K3), or CpG-C(2395) induced interleukin (IL)-10 expression without causing cell injury. The effects of pretreatment with CpG-ODNs before subsequent lipopolysaccharide stimulation were also evaluated. Interestingly, pretreatment with only CpG-C(2395) resulted in high expression levels of IL-10 mRNA in the presence of lipopolysaccharide. Finally, gene expression analysis of inflammation-related cytokines and receptors revealed that pre-treatment with CpG-C(2395) significantly reduced the mRNA expression of tumor necrosis factor-α, IL-1β, IL-6, and Toll-like receptor 4. Overall, these results shed light on the anti-inflammatory responses triggered by CpG-C(2395) stimulation through a comparative analysis of five types of CpG-ODNs in chicken macrophages. These results also offer insights into the use of CpG-ODNs to suppress the expression of proinflammatory cytokines, which may be valuable in the prevention of avian infectious diseases in the poultry industry.