Induction of interleukin-6 and interleukin-12 in bovine B lymphocytes, monocytes, and macrophages by a CpG oligodeoxynucleotide (ODN 2059) containingthe GTCGTT motif

Bacterial DNA and synthetic oligodeoxynucleotides (ODN) that contain unmeth ylated CpG dinucleotides flanked by certain bases (CpG ODN) have been shown to activate murine and human B cells and to induce proinflammatory cytokin es by monocytes/macrophages and dendritic cells (DC). However, the CpG ODN sequences optimal for mice and humans are different. In the current study, the effects of CpG ODN, which were defined to stimulate strong responses in either mouse or human leukocytes, were compared for stimulation of bovine B lymphocyte proliferation and macrophage cytokine mRNA expression. The opt imal CpG ODN was then tested for induction of cytokines in peripheral blood mononuclear cells (PBMC) and purified B lymphocytes, monocytes, and macrop hages. At a high ODN concentration (40 muM), all but two CpG ODN tested sti mulated B cell proliferation, which was dependent on unmethylated CpG motif s. CpG ODN 2059 containing the GTCGTT motif shown to activate human leukocy tes also promoted the highest level of bovine B cell proliferation at a low er concentration (10 muM) when compared with CpG ODN containing AACGTT or G ACGTT motifs active for murine leukocytes. Furthermore, ODN 2059 induced in terleukin-6 (IL-6) production by B lymphocytes and IL-6 and IL-12 productio n by PBMC, monocytes, and macrophages. In contrast, IL-1 beta and tumor nec rosis factor-alpha (TNF-alpha) production was either very low or undetectab le. Consistent with increased IL-12 production, ODN 2059 also stimulated in terferon-gamma (IFN-gamma) production by PBMC. Importantly, the levels of c ytokines induced by ODN 2059 were comparable to those generated in response to Escherichia coli DNA. The weak TNF-alpha response combined with the vig orous IL-6 and IL-12 response to ODN 2059 indicate the potential use of thi s CpG ODN as an adjuvant to enhance both antibody-mediated and IFN-gamma -m ediated macrophage activation, which are important for protection against d isease caused by intracellular pathogens of cattle.