A serine/threonine kinase, Cot/Tpl2, modulates bacterial DNA-induced IL-12 production and Th cell differentiation.
A serine/threonine protein kinase, Cot/Tpl2, is indispensable for extracellular signal-regulated kinase (ERK) activation and production of TNF-alpha and PGE2 in LPS-stimulated macrophages. We show here that Cot/Tpl2 is also activated by other Toll-like receptor (TLR) ligands. Bacterial DNA rich in the dinucleotide CG (CpG-DNA), unlike LPS or synthetic lipopeptide, activated ERK in a Cot/Tpl2-independent manner. Peritoneal macrophages and bone marrow-derived DCs from Cot/Tpl2-/- mice produced significantly more IL-12 in response to CpG-DNA than those from WT mice. Enhanced IL-12 production in Cot/Tpl2-/- macrophages is, at least partly, regulated at the transcriptional level, and the elevated IL-12 mRNA level in Cot/Tpl2-/- macrophages is accompanied by decreased amounts of IL-12 repressors, such as c-musculoaponeurotic fibrosarcoma (c-Maf) and GATA sequence in the IL-12 promoter-binding protein (GA-12-binding protein; GAP-12) in the nucleus. Consistently, Cot/Tpl2-/- mice showed Th1-skewed antigen-specific immune responses upon OVA immunization and Leishmania major infection in vivo. These results indicate that Cot/Tpl2 is an important negative regulator of Th1-type adaptive immunity, that it achieves this regulation by inhibiting IL-12 production from accessory cells, and that it might be a potential target molecule in CpG-DNA-guided vaccination.
Sugimoto
Kenji
K
Division of Host Defense, Center for Neural Disease and Cancer, Nagoya University Graduate School of Medicine, Japan.
Ohata
Mutsuhiro
M
Miyoshi
Jun
J
Ishizaki
Hiroyoshi
H
Tsuboi
Naotake
N
Masuda
Akio
A
Yoshikai
Yasunobu
Y
Takamoto
Masaya
M
Sugane
Kazuo
K
Matsuo
Seiichi
S
Shimada
Yasuhiro
Y
Matsuguchi
Tetsuya
T
D000818:Animals; D001483:Base Sequence; D018929:Cell Culture Techniques; D017931:DNA Primers; D004269:DNA, Bacterial / Q000276:immunology*; D005091:Exons; D018664:Interleukin-12 / Q000096:biosynthesis*; D020930:MAP Kinase Kinase Kinases / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000276:immunology; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018417:Th1 Cells / Q000276:immunology*
D017931:DNA Primers; D004269:DNA, Bacterial; D011518:Proto-Oncogene Proteins; D018664:Interleukin-12; D020930:MAP Kinase Kinase Kinases; C489843:Map3k8 protein, mouse