Bacterial DNA containing methylated CpG motifs retains immunostimulatory activity in synergy with modified lipopolysaccharides.
We previously described the immunostimulatory activity of CIA07, a combination of bacterial DNA fragments and modified LPS, and demonstrated that CIA07 has antitumor activity in a mouse bladder cancer model. In this study, we investigated whether methylation of the CpG motifs on the bacterial DNA fragments affects the immunostimulatory potential of CIA07. E. coli DNA fragments were methylated with CpG methylase, and then combined with modified LPS for experiments. Our results revealed that methylated CIA07 (mCIA07) and unmethylated CIA07 were equally active in inducing cytokine secretion from human whole blood cells. In addition, both methylated DNA fragments and mCIA07 retained the ability to activate expression and nuclear translocation of NF-kappaB in RAW 264.7 cells. Finally, methylated DNA fragments and mCIA07 exhibited an antitumor activity comparable to those of their unmethylated counterparts in our mouse bladder cancer model. These data demonstrate that CpG methylation of E. coli DNA does not abrogate the immunostimulatory activity of DNA fragments or CIA07, suggesting that the synergistic activity by bacterial DNA in combination with LPS may be independent of the methylation status of CpG motifs.
Cho
Yang Je
YJ
Department of Biochemistry, College of Science, Yonsei University, Seoul, Korea.
Ahn
Bo Young
BY
Song
Eun Sun
ES
Park
Shin Ae
SA
Lee
Dong Hyeon
DH
Kim
Doo-Sik
DS
Lee
Na Gyong
NG
D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D019175:DNA Methylation; D004269:DNA, Bacterial / Q000276:immunology / Q000494:pharmacology*; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D007371:Interferon-gamma / Q000276:immunology; D053762:Interleukin-12 Subunit p40 / Q000276:immunology; D008070:Lipopolysaccharides / Q000276:immunology / Q000494:pharmacology*; D008156:Luciferases / Q000378:metabolism; D008264:Macrophages; D051379:Mice; D008809:Mice, Inbred C3H; D009838:Oligodeoxyribonucleotides / Q000276:immunology / Q000494:pharmacology*; D001749:Urinary Bladder Neoplasms / Q000276:immunology / Q000628:therapy*
D000276:Adjuvants, Immunologic; D004269:DNA, Bacterial; D053762:Interleukin-12 Subunit p40; D008070:Lipopolysaccharides; D009838:Oligodeoxyribonucleotides; C483020:ProMune; D007371:Interferon-gamma; D008156:Luciferases