The production and immunostimulatory activity of double-stranded CpG-DNA

CpG-DNA, which contains unmethylated CpG dinucleotides in the context of specific sequences, has remarkable and diverse immunological effects, including induction of proinflammatory cytokine expression and regulation of the Th1/Th2 immune response. Here, we examined the immunostimulatory activities of double-stranded (ds) CpG-DNA in the human B cell line RPMI8226. To investigate whether dsCpG-DNA stimulates immune cells, we constructed a plasmid containing repeated dsCpG-DNA and produced dsCpG-DNA by PCR amplification and EcoR I digestion. PCR-amplified dsCpG-DNA alone did not have immmunostimulatory activity. However, dsCpG-DNA encapsulated with lipofectin induced IL-8 promoter activation, HLA-DRA expression, and IL-8 expression in a CG sequence-independent manner. The effects of encapsulated dsCpG-DNA were independent of minor endotoxin contamination. These findings suggest the potential use of dsCpG-DNA as a therapy for immune response regulation. [BMB reports 2010; 43(3): 164-169]