Mechanism and Function of a Newly Identified CpG DNA Motif in Human Primary B Cells

Hartmann, Gunther; Krieg, Arthur Μ.

doi:10.4049/jimmunol.164.2.944

Cited by 541 publications

(483 citation statements)

References 45 publications

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“…To further investigate this, we used a transwell system to separate NKT cells (PDC-depleted NKT cell enriched PBMC) from PDC. In this setting, neither CpG ODN 2216 or CpG ODN 2006 [53] enhanced a-GalCer-dependent IFN-c production of NKT cells (Fig. 8B, left panel).…”

Section: Cpg Odn-triggered Ifn-c Production In Nkt Cells Requires Celmentioning

confidence: 91%

CpG ODN enhance antigen-specific NKT cell activation via plasmacytoid dendritic cells

et al. 2005

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Human Va24 + Vb11 + natural killer T cells (NKT cells) are "natural memory" T cells that detect glycolipid antigens such as a-galactosylceramide (a-GalCer) presented on CD1d.In the present study we found that highly purified Va24 + NKT cells lack TLR9 mRNA, and thus are not sensitive towards stimulation with CpG oligodeoxynucleotides (ODN). Within PBMC, however, CpG ODN synergistically activated NKT cells stimulated with their cognate antigen a-GalCer. Depletion of plasmacytoid dendritic cells (PDC) or myeloid dendritic cells (MDC) revealed that both DC subsets were necessary for the synergistic activation of NKT cells by a-GalCer and CpG ODN. While PDC were responsible for the stimulation of NKT cells with CpG ODN, MDC but not PDC presented a-GalCer via CD1d. Partial activation of NKT cells was mediated by PDC-derived IFN-a, whereas full activation of NKT cells as indicated by IFN-c production required cell-tocell contact of PDC and NKT cells in addition to IFN-a; OX40 was involved in this interaction. We conclude that CpG-activated PDC enhance a-GalCer-specific NKT cell activation, and bias activated NKT cells towards a Th1 phenotype. Our results lead to a novel concept of PDC function: to regulate effector activity of antigen-stimulated T cells in a cell contact-dependent manner without the need of simultaneous presentation of the cognate T cell antigen. IntroductionNatural killer T (NKT) cells represent a small subset of non-conventional innate T cells with a restricted TCR repertoire for the recognition of glycolipid antigens presented on CD1d, an MHC class I-like molecule. NKT cells express markers of NK cells and exhibit an activated memory phenotype. Depending on the microenvironment and the type of stimulation, they can release large amounts of both Th1 and Th2 cytokines (especially IL-4 and IFN-c) and show cytotoxic activity in vitro (reviewed in [1][2][3]). In both mice and man NKT cells express a homologous semi-invariant TCR that in humans consists of a Va24 chain preferentially paired with a Vb11 chain [4]. In mice, NKT cells are most frequent in the liver (about 30% of hepatic T cells), bone marrow and thymus (reviewed in [5]). Smaller NKT cell populations are present in spleen and blood (reviewed in [5]). Similar to their murine counterparts, human NKT cells preferen-A. M., S. R. and V. H. equally contributed to this manuscript. tially accumulate in the liver though with a far lower frequency than in mice (4% of hepatic T cells) ([6, 7] and reviewed in [1,5]). Due to the conserved TCR, both mouse and human NKT cells recognise the same specific glycolipid antigen a-galactosylceramide (a-GalCer) when presented by CD1d molecules on antigen-presenting cells (APC) [8][9][10]. Originally isolated from a marine sponge, aGalCer was first described as an agent with strong antimetastatic activity in mice and later found to specifically activate NKT cells in a CD1d-restricted manner [8,11,12]. Glycolipid antigens similar to a-GalCer have been detected in certain bacteria and under some abnormal conditions...

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Section: Cpg Odn-triggered Ifn-c Production In Nkt Cells Requires Celmentioning

confidence: 91%

CpG ODN enhance antigen-specific NKT cell activation via plasmacytoid dendritic cells

et al. 2005

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“…Neither these P-ODN nor another CpG P-ODN (P2080) with recognized immuno-modulatory properties on human cells [20] induced neutrophil activation or supported neutrophil migration ( Fig. 3D-F).…”

Section: Effect Of Odn Containing Cpg Motifs On Neutrophil Functionmentioning

confidence: 97%

“…A. baumannii DNA was obtained from strains isolated from intensive care unit patients and prepared as described previously [55]. TZGTZGTTTTGTZGTTTTGTZGTT [20]. All ODN were used ss and HPLC-purified and were chosen on the basis of their abilities to induce strong activation of human immune cells [8,20,32,33].…”

Section: Genomic Dna and Odn Preparationsmentioning

confidence: 99%

Bacterial DNA activates human neutrophils by a CpG‐independent pathway

et al. 2003

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Bacterial DNA stimulates macrophages, monocytes, B lymphocytes, NK cells, and dendritic cells in a CpG-dependent manner. In this work we demonstrate that bacterial DNA, but not mammalian DNA, induces human neutrophil activation as assessed by L-selectin shedding, CD11b upregulation, and stimulation of cellular shape change, IL-8 secretion, and cell migration. Induction of these responses is not dependent on the presence of unmethylated CpG motifs, as neutrophil stimulatory properties were neither modified by CpG-methylation of bacterial DNA nor reproduced by oligonucleotides bearing CpG motifs. We found that human neutrophils express Toll-like receptor (TLR) 9 mRNA. However, as expected for a CpG-independent mechanism, activation does not involve a TLR9-dependent signaling pathway; neutrophil stimulation was not prevented by immobilization of bacterial DNA or by wortmannin or chloroquine, two agents that inhibit TLR9 signaling. Of note, both singlestranded and double-stranded DNA were able to induce activation, suggesting that neutrophils might be activated by bacterial DNA at inflammatory foci even in the absence of conditions required to induce DNA denaturation. Our findings provide the first evidence that neutrophils might be alerted to the presence of invading bacteria through recognition of its DNA via a novel mechanism not involving CpG motifs.

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“…B cells and PDC, the two cell types in human blood that express TLR-9, can be inhibited with IRS in response to ISS activation despite their very different responses to ISS activation. Human B cells proliferate and produce the cytokines IL-6 and IL-10, whereas PDC will respond with a vigorous production of IFN-␣ (17,24). The different classes of ISS will also trigger very different quantitative responses in these cell subsets.…”

Section: Discussionmentioning

confidence: 99%

“…In human peripheral blood, B cells and PDCs are the two main subsets of cells that express TLR-9, although ISS elicit quite different cytokine responses from each. In response to ISS stimulation, B cells secrete proinflammatory cytokines such as IL-6, whereas PDCs secrete predominantly IFN-␣ (4,17,24). In addition, when stimulated with ISS and CD40L, PDC can produce moderate amounts of IL-12 (17,25).…”

Section: Irs Inhibits Iss-induced Ifn-␣ From Human Pdcmentioning

confidence: 99%

Inhibitors of TLR-9 Act on Multiple Cell Subsets in Mouse and Man In Vitro and Prevent Death In Vivo from Systemic Inflammation

Duramad

Fearon

Chang

et al. 2005

The Journal of Immunology

111

125

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In parallel with the discovery of the immunostimulatory activities of CpG-containing oligodeoxynucleotides, several groups have reported specific DNA sequences that could inhibit activation by CpG-containing oligodeoxynucleotides in mouse models. We show that these inhibitory sequences, termed IRS, inhibit TLR-9-mediated activation in human as well as mouse cells. This inhibitory activity includes proliferation and IL-6 production by B cells, and IFN-α and IL-12 production by plasmacytoid dendritic cells. Our studies of multiple cell types in both mice and humans show the optimal IRS to contain a GGGG motif within the sequence, and the activity to require a phosphorothioate backbone. Although the GGGG motif readily itself leads to formation of a tetrameric oligodeoxynucleotide structure, inhibitory activity resides exclusively in the single-stranded form. When coinjected with a CpG oligodeoxynucleotide in vivo, IRS were shown to inhibit inflammation through a reduction in serum cytokine responses. IRS do not need to be injected at the same site to inhibit, demonstrating that rapid, systemic inhibition of TLR-9 can be readily achieved. IRS can also inhibit a complex pathological response to ISS, as shown by protection from death after massive systemic inflammation induced by a CpG-containing oligodeoxynucleotides.

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Mechanism and Function of a Newly Identified CpG DNA Motif in Human Primary B Cells

Cited by 541 publications

References 45 publications

CpG ODN enhance antigen-specific NKT cell activation via plasmacytoid dendritic cells

CpG ODN enhance antigen-specific NKT cell activation via plasmacytoid dendritic cells

Bacterial DNA activates human neutrophils by a CpG‐independent pathway

Inhibitors of TLR-9 Act on Multiple Cell Subsets in Mouse and Man In Vitro and Prevent Death In Vivo from Systemic Inflammation

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