PATTERN AND KINETICS OF CYTOKINE PRODUCTION FOLLOWING ADMINISTRATION OF PHOSPHOROTHIOATE OLIGONUCLEOTIDES IN MICE

Phosphorothioate oligonucleotides with certain sequences or structure motifs can stimulate the immune system, We administered to mice a 27-m er phosphorothioate oligonucleotide (sequence 5'-TCG TCG CTG TCT CCG C TT CTT CTT GCC-3'), which has previously been shown to cause splenomeg aly and hypergammaglobulinemia on in vivo administration in mice, and studied the pattern and kinetics of cytokine production at both the sp lenic mRNA and serum protein levels, Following i.p. administration of 50 mg/kg of oligonucleotide, significant increases in the splenic mRNA levels of IL-6, IL-12p40, IL-1 beta, and IL-1Ra and serum levels of I L-6, IL-12, MIP-1 beta, and MCP-1 were observed. In contrast, no signi ficant differences in splenic mRNA levels of IL-2, IL-4, IL-5, IL-9, I L-13, IL-15, IFN-gamma, or MIF or serum levels of IL-2, IL-4, IL-5, IL -10, IFN-gamma, or GM-CSF were detected, The induction of IL-12 secret ion was dependent on the sequence and dose of the oligonucleotides, On e oligonucleotide (sequence 5'-GAG AAC GCT CGA CCT TCG AT-3') induced a high level of IL-12 secretion even at 5 mg/kg, whereas another oligo nucleotide (sequence 5'-CTC TGC CAC CCA TCT CTC TCC TTC T-3') did not induce significant IL-12 secretion even at 50 mg/kg, IL-12 secretion i nduced by various doses of oligonucleotide has the same kinetics but d iffers in magnitude, These studies show a distinct pattern and kinetic s of cytokine production following oligonucleotide administration and further demonstrate that cytokine induction is not a general property of phosphorothioate oligonucleotides but is dependent on the sequence and dose of the oligonucleotides.