SummaryProblemThe purpose of the present invention is to provide: a chiral nucleic acid adjuvant having anti-tumor activity and an anti-tumor agent.SolutionThe present invention relates to an adjuvant for anti-tumor agent, wherein the adjuvant comprises oligonucleotides which comprise two to four CpG motif each represented by 5′-X1CpGX2-3′ and has a length of 14 to 32 nucleotides, wherein a nucleic acid at 3′ end side of at least two CpG motifs is connected by phosphorothioate linkage, wherein each nucleic acid at 3′ end and 5′ end of the oligonucleotide is S type nucleic acid connected by phosphorothioate linkage, and wherein the oligonucleotide comprises at least one nucleic acid without phosphorothioate modification. The present invention relates to an anti-tumor agent containing its adjuvant.
