[Anti-tumor immunity induced by OK-432-derived DNA].
We have tried to identify the effective components of OK-432, a Streptococcus-derived anti-cancer immunotherapeutic agent. In the current study, we investigated the effect of OK-432-derived DNA (OK-DNA) in augmenting anti-cancer immune response. Analysis of OK-DNA with the restriction enzymes Hpa II and Msp I revealed that OK-DNA contained unmethylated CpG motifs. OK-DNA induced Th1-type cytokines, such as IFN-gamma and IL-12, and augmented killer cell activities in vitro on human peripheral blood mononuclear cells, whereas the methylated OK-DNA did not. Cytokines were also produced by OK-DNA-stimulated splenocytes derived from wild-type mice but not from TLR9-deficient mice. In the in vivo study, a peritumoral administration of OK-DNA resulted in a significant inhibition of tumor growth in syngeneic tumor-bearing wild-type and TLR4-deficient mice but not in TLR9-deficient mice. Anti-tumor effect of OK-432 in TLR9-deficient mice was significantly but partially reduced as compared with that in wild-type mice, while the effect of OK-432 was almost completely eliminated in TLR4-deficient mice. These findings suggest that unmethylated CpG-DNA in OK-432 functions as an active component in OK-432-induced anti-cancer immunity via TLR9, at least in part.
Oshikawa
Tetsuya
T
Second Dept. of Oral and Maxillofacial Surgery, Tokushima University School of Dentistry.
Okamoto
Masato
M
Ahmed
Sharif Uddin
SU
Tano
Tomoyuki
T
Sasai
Akiko
A
Kan
Shin
S
Sato
Mitsunobu
M
D000818:Animals; D002478:Cells, Cultured; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D007371:Interferon-gamma / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D009374:Neoplasms, Experimental / Q000276:immunology*; D010844:Picibanil / Q000032:analysis* / Q000494:pharmacology; D013154:Spleen / Q000166:cytology; D051217:Toll-Like Receptor 9 / Q000502:physiology
D004269:DNA, Bacterial; D051217:Toll-Like Receptor 9; D018664:Interleukin-12; D010844:Picibanil; D007371:Interferon-gamma