Synthetic Oligodeoxynucleotides (ODN) expressing CpG
motifs (CpG-ODN) mimic the immunostimulatory activity of bacterial
DNA and are commonly used to activate Toll Like Receptor 9 (TLR9) for
therapeutic applications. CpG-ODN can counteract the activity of DNAdamaging
chemotherapy and radiation therapy on immune cell and
enhance immunity in preclinical mouse models. We hypothesized that
these actions of CpG-ODN on immune cells are expressed by modulation
of DNA repair genes. We conducted a PCR array analysis of DNA repair
genes expression in splenocytes obtained from mice injected
intraperitoneally with CpG-ODN and/or Cisplatin. CpG-ODN modulate
expression of DNA repairing genes inducing down regulation in most of
DNA repairing genes but up regulate some genes participate in biological
processes suggesting the role of CpG-ODN in these processes. Cisplatin
had an effect on expression of DNA repairing genes inducing up regulation
of most genes implicated in repair of toxic effect of Cisplatin. We concluded
that the effect of CpG-ODN in elimination of DNA damaging activity of
Cisplatin on immune cells appear as counteracting and normalizing the
modulation of repair genes expression occurred by Cisplatin.