An integrated transcriptomics and metabolomics study of the immune response of newly hatched chicks to the CpG-ODN stimulation

This study aims at identifying a dual transcriptomics and metabolomics blood signature following administration of CpG-ODN (cytosine-phosphate-guanine oligodeoxynucleotides), a reference immune-stimulatory molecule. A clinical study was conducted with chicks and transcriptomics and metabolomics analyses were performed on whole-blood and plasma samples respectively. Statistical analyses resulting in lists of differentially expressed genes and metabolites with different abundance were identified in chicks treated with CpG-ODN. The results showed that CpG-ODN activates the innate immune systems within hours following administration and its effect lasts over time, as metabolomic and transcriptomic profiles are still varying at 6 days after administration. CpG-ODN 2007, a prototypal immunomodulator, described as one of the most efficient agonists of chTLR21, the counterpart of mammalian TLR9, was injected at day of hatch and systemic changes were monitored in blood at different time points post injection. An early time point of 3h (D0+3h) post injection was chosen to secure early signature following CpG-ODN injection. As the immunomodulatory properties of CpG-ODN have been evaluated up to 4 days post-injection in the spleen, two additional time points to frame this timing at day three (D3) and day six (D6) were chosen to assess its functional effects over time