| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
production involves p38 MAPK-dependent STAT1 phosphorylation in human plasmacytoid dendritic cell precursors
Departments of
* Forensic Medicine and
Immunology and Medical Zoology and
# Division of Transfusion Medicine, Faculty of Medicine, Fukui Medical University, Japan;
Department of Bacterial and Blood Products, National Institute of Infectious Diseases, Tokyo, Japan;
Department of Hematology and Clinical Immunology, Kobe City General Hospital, Japan;
|| Chemicals Development Group, Emori & Co., Ltd., Fukui, Japan; and
** Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Japan
Correspondence: Dr. Takasumi Matsuki, Department of Forensic Medicine, or Dr. Sumiko Iho, Department of Immunology and Medical Zoology, Faculty of Medicine, Fukui Medical University, 23 Shimoaizuki, Matsuoka-cho, Yoshida-gun, Fukui 910-1193, Japan. E-mails: tmatsuki@fmsrsa.fukui-med.ac.jp or ihosumik{at}fmsrsa.fukui-med.ac.jp
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
, but the molecular mechanisms involved remain unknown. We found that CpG-DNA-induced IFN- production in PDC was completely impaired by the inhibitor of the p38 mitogen-activated protein kinase (MAPK) pathway. Expression of IFN regulatory factor (IRF)-7 was enhanced by CpG-DNA treatment, which was preceded by the phosphorylation of signal transducer and activator of transcription (STAT)1 on Tyr-701, as well as its enhanced phosphorylation on Ser-727. All of these events were also suppressed by the p38 MAPK inhibitor. STAT1, STAT2, and IRF-9, components of IFN-stimulated gene factor 3 (ISGF3), were recognized in the nuclear fraction of CpG-DNA-treated cells. Neither anti-IFN-/ß antibodies (Ab) nor anti-IFNAR Ab suppressed STAT1 phosphorylation, enhancement of IRF-7 expression, or IFN- production in the early phase of the culture. These results suggest that CpG DNA induces p38 MAPK-dependent phosphorylation of STAT1 in a manner independent of IFN-/ß, which may cause ISGF3 formation to increase the transcription of the IRF-7 gene, thereby leading to IFN- production in human PDC.
Key Words: IRF-7 • STAT2 • IRF-9 • TLR-9
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
, interleukin (IL)-12, and IL-6 [4
5
6
7
]. Therefore, CpG DNA functions as adjuvants for regulating the initiation of T helper cell type 1 differentiation [8
]. In the study of molecular mechanisms for this cytokine production in mouse, it was elucidated that the recognition of CpG DNA is mediated by the Toll-like receptor (TLR)-9 [9
], and the signaling is transduced in a manner similar to lipopolysaccharide (LPS) and to peptidoglycan via TLR-4 and TLR-2, respectively [10
], which involves sequential recruitment of an adaptor molecule, myeloid differentiation marker (MyD)88, IL-1R-associated kinase (IRAK), and TNF receptor-associated factor-6. The signal is subsequently transduced to the activation of inhibitor of nuclear factor (NF)-
B (I-B) kinase (IKK) and stress kinases, c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK). NF-B, activated through IKK-dependent degradation of I-B and activating protein-1 induced by JNK, are essential factors for the production of proinflammatory cytokines [5
, 9
].
In human DC, the precise responsiveness against CpG DNA, which is often quite different from that of mouse DC [7
, 11
], and the mechanisms involved have not been fully investigated. Recently, CD4+CD3-CD11c- type 2 DC precursors (pre-DC2), known as plasmacytoid DC precursors (PDC) [12
], were identified as natural interferon (IFN)-producing cells in response to viruses, bacteria, and tumor cells [13
]. Kadowaki et al. [14
] reported that pre-DC2 respond to immunostimulatory CpG DNA to produce IFN-. Bauer et al. [15
] also demonstrated that CpG DNA promotes the survival and maturation of CD11c-CD123+ PDC, but the mechanisms by which CpG DNA induces IFN- and stimulates immune systems remain unknown.
We previously reported that CpG DNA with certain palindromic sequences stimulated human peripheral blood mononuclear cells (PBMC) to produce IFNs [16
] and found that the guanosine-backbone CpG DNA had more potent activity in mice and humans [17
, 18
]. Using this type of CpG DNA, we tried to elucidate the molecular mechanism(s) of CpG-DNA-inducing IFN- production in human PDC consisting in a very small population in peripheral blood cells.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Isolation and culture of cells
PBMC were isolated from the peripheral blood of healthy volunteers with informed consent, and the low-density fraction was separated on 47.4% Percoll (Amersham Pharmacia Biotech, Arlington Heights, IL). To enrich PDC, the low-density cells were treated with a mixture of anti-CD14, anti-CD3, anti-CD19, anti-CD56, anti-CD16, and anti-CD11c monoclonal antibodies (mAb; Pharmingen Becton Dickinson Co., San Diego, CA) followed by magnetic bead-depletion with Dynabeads® M-450 goat antimouse immunoglobulin G (Dynal, Oslo, Norway). In each step, magnetic bead-depletion was repeated twice to completely purge the lineage- and CD11c-positive cells, thereby obtaining >85% CD4+/lineage marker-/CD11c- cells in the PDC-enriched population. CD4+ cells isolated from the PDC-enriched population by the M-450 CD4 (Dynal)-separation method produced a huge amount of IFN- in response to CpG DNA, but the remaining cells were nonresponsive in our preliminarily experiments. As the cells yielded by further isolation of CD4+ cells were too few to use in this study, we used the PDC-enriched population as CpG-DNA-targeted cells in most of the experiments. BDCA-4 [21
] (Miltenyi Biotec, Auburn, CA)-positive cells were also isolated by the magnetic bead-separation method (>98%) and were used in certain experiments to verify the data representing PDC responsiveness. The cells were incubated in RPMI 1640 (Sigma Chemical Co., Poole, UK) containing 10% heat-inactivated fetal calf serum (Equitech-Bio, Ingram, TX; endotoxin <0.03 ng/ml) at 1 x 105 cells/0.2 ml, unless otherwise indicated, in 96-well culture plates for the indicated period. For Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR), when necessary, different donor PDC were individually incubated at 5–7 x 105 cells/0.1 ml, and each culture was pooled together under the same experimental conditions to obtain the appropriate amount for the assay.
Antibodies and reagents
Antiphospho-p38 MAPK and anti-p38 MAPK Ab were purchased from Cell Signaling Technology (Beverly, MA). Antisignal transducer and activator of transcription (STAT1; pS727 and pY701) phosphospecific Ab were from Biosource International (Camarillo, CA). Anti-IFN-regulatory factor (IRF)-7, anti-IRF-3, anti-IRF-9, anti-STAT2, and anti-histone H1 Ab were from Santa Cruz Biotechnology (Santa Cruz, CA). Anti-STAT1 Ab was from Transduction Laboratories (Lexington, KY). Anti-IFNAR Ab (Pestka Biomedical Laboratories, New Brunswick, NJ) was used at 1.0 µg/ml, which blocked the IFN--induced STAT1 phosphorylation in the preliminary experiments. Anti-IFN- (Pestka Biomedical Laboratories) and anti-IFN-ß Ab (Genzyme/Techne, Boston, MA) were mixed together at 1 µg/ml and 0.5 µg/ml, respectively, and were used as anti-IFN-/ß Ab. IFN- (Hayashibara Biochemical Laboratories, Okayama, Japan), LPS (Sigma Chemical Co.), and polymxin B (Sigma Chemical Co.) were used at 500 IU/ml, 100 ng/ml, and 50 U/ml, respectively. p38 MAPK inhibitors, SB203580 [22
] and SB202190, and the inactive analogue, SB202474 [23
], were purchased from Calbiochem Inc. (San Diego, CA). Chloroquine was from Sigma Chemical Co.
Assay of cytokines in culture supernatants
Cytokine assay was carried out by enzyme-linked immunosorbent assay (ELISA) according to the manufacturers’ instructions (Biosource International for IFN-, TNF-, IL-6, and IL-12; TFB Inc., Tokyo, Japan, for IFN-ß).
RT-PCR
Total RNA (1 µg) was converted to cDNA by RT using a SuperScript first-strand synthesis system for RT-PCR (Invitrogen, Carlsbad, CA) with oligo(dt) primer. PCR amplification was performed by using a GeneAmp PCR System 9700 (PE Applied Biosystems, Foster City, CA). The reaction mixture consisted of 2 µl sample cDNA, 5 µl PCR amplification buffer, 2 µl 25 mM MgCl2, 4 µl 2.5 mM dNTPs, 0.3 µl AmpliTaq DNA polymerase (5 U/µl; PE Applied Biosystems), 2 µl 20 mM primer, and 29.7 µl double-distilled water to bring the final volume to 50 µl. The sequences of the primers were as follows: 5'-GTACTGCAGAATCTCTCCTTTCTCCTG-3' (sense) and 5'-GTGTCTAGATCTGACAACCTCCCAGGGCACA-3' (anisense) for all subtypes of IFN- [24
]; 5'-TGCAAGGTGTACTGGGAG-3' (sense) and 5'-TCAAGCTTCTGCTCCAGCTCCATAAG-3' (antisense) for IRF-7 [24
]; and 5'-TGGAATCCTGTGGCATCCATGAAAC-3' (sense) and 5'-TAAAACGCAGCTCAGTAACAGTCCG-3' (antisense) for ß-actin. The mixture was first incubated at 95°C for 5 min, then cycled 25 times at 95°C for 1 min, 50°C for 1 min, 72°C for 1 min, and elongated at 72°C for 10 min. The PCR products were electrophoresed on 2% agarose gels. The gels were stained with ethidium bromide and photographed.
Preparation of whole cell lysates, cytoplasmic, and nuclear extracts
Cells were washed with cold phosphate-buffered saline (PBS) and lysed on ice for 20 min with lysis buffer containing 50 mM Tris (pH 7.6), 150 mM NaCl, 1% Triton X-100, and protease inhibitors (Complete Mini, Roche, Mannheim, Germany). The whole cell lysates were harvested by centrifugation at 15,000 rpm at 4°C for 10 min. For the preparation of the cytoplasmic and nuclear fractions, the cells were incubated in the buffer containing 50 mM Tris (pH 7.6), 250 mM sucrose, 25 mM KCl, 5 mM MgCl2, and 0.25% Triton X-100 for 15 min on ice and were centrifuged at 6000 rpm. This procedure was repeated twice, and the first supernatants were harvested as a cytoplasmic fraction. The pellets were incubated in the buffer containing 20 mM Tris (pH 7.6), 350 mM NaCl, 5 mM MgCl2, 1 mM EGTA, and protease inhibitors for 20 min on ice. The nuclear fraction was harvested by centrifugation at 15,000 rpm at 4°C for 20 min. To obtain an adequate amount for loading, the lysates from different donors were separately harvested and gathered under the same experimental conditions for each sample.
Western blotting
The normalized amounts of cell lysates or extracts were mixed with loading buffer and heat-denatured. Proteins were resolved on a 10% polyacrylamide gel and transferred to a polyvinylidene difluoride membrane by electroblotting, and the membrane was blocked for 60 min in PBS containing 0.1% Tween-20 and 1% nonfat dried milk. Then, it was incubated with diluted antibody for 1 h at room temperature or at 4°C overnight. After washing, the membrane was incubated with the corresponding second antibody conjugated with horseradish peroxidase. Signals were detected using enhanced chemiluminescence (Amersham). For reprobing, the membrane was first stripped by incubating in reprobe buffer containing 2% SDS, 100 mM 2-mercaptoethanol, and 62.5 mM Tris-HCl (pH 6.8) for 30 min at 50°C.
Statistical analysis
Statistical significance was evaluated using Student’s or paired t-test at P < 0.01.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
production in PDC and a small amount of IFN-ß, and the production of IL-12 was very little (Table 1
). The IFN--inducing activity of g10gacga was much higher than that of AAC-30 [16
], pd-1585 [20
], or 2006 [19
], and therefore, we used g10gacga as the representative CpG DNA in this study. The production of TNF- and IL-6 was statistically insignificant. Neither control oligo DNA (2GC) nor LPS induced IFN- production. In addition, the CD4+ cell-depleted population did not respond to CpG DNA (data not shown). Therefore, CpG-DNA-induced IFN- production is ascribed to CpG-DNA-activated PDC.
|
in PDC was detected after 6 h incubation with CpG DNA, markedly increased thereafter, and reached a plateau at 18 h (Fig. 1
). Cytokine production by CpG-DNA-treated murine cells is elicited through the process that includes endosomal maturation and p38 MAPK-dependent signal transduction [5
]. In an 18-h culture of PDC, SB203580, an inhibitor of the p38 MAPK pathway [22
], and chloroquine, an inhibitor of endosomal maturation [5
], independently and completely suppressed CpG-DNA-induced IFN- production when they were added within 6 h, and their effects diminished along with the delayed addition (Fig. 2A
). The mechanism of IFN- production seems to be altered in the late phase. Anti-IFNAR Ab failed to suppress IFN- production within an 8-h culture but partially suppressed when the culture was carried out 10 h and more (Fig. 2B)
. Once PDC are stimulated by CpG DNA to produce IFN-, its production in the late phase seems to depend largely on secreted IFN- in an autocrine manner. In this study, we focused on the CpG-DNA-inducing initial signaling cascades that trigger IFN- production in PDC.
|
|
/ß gene expression is introduced by the biphasic mechanism [25
26
27
]. During the early phase, the production of small amounts of IFN-ß and/or IFN-4 precedes via virus-induced activation of constitutively expressed IRF-3 and IRF-7. During the late phase, secreted IFN-ß and/or IFN-4 feed back to the cells and strongly promote IRF-7 gene transcription through activation of IFN-stimulated gene factor 3 (ISGF3), the transcriptional complex consisting of STAT1, STAT2, and IRF-9. Then, activated IRF-7 and IRF-3 cooperatively act on the IFN-/ß gene to induce intrinsic IFN-/ß production. Especially in the transcriptional activation of the IFN- gene, IRF-7 is the critical determinant [24
, 28
29
30
].
We found that IRF-7 was constitutively expressed in PDC, and its expression was stimulated after 5–6 h incubation with CpG DNA (Fig. 3A
and 3B
). CpG-DNA-enhanced IRF-7 expression was also observed in BDCA-4 [21
]-positive PDC in a similar time course and did not change in the presence of the LPS inhibitor polymyxin B (data not shown). Therefore, the enhanced IRF-7 expression is considered to be derived solely from CpG-DNA-stimulated PDC. The weak inducers of IFN-, AAC-30, and pd-1585 (Table 1)
showed weak enhancements in IRF-7 expression (29% and 22% of g10gacga, respectively, as analyzed by a densitometer), and non-IFN--inducing type 2006 did not enhance IRF-7. Therefore, it seems that CpG-DNA-induced IFN- production is associated with IRF-7 expression. As demonstrated in IFN- production, enhancement of IRF-7 expression was abrogated in the presence of SB203580 (Fig. 3B
, top). This abrogation was also observed with another p38 MAPK inhibitor, SB202190, but not with the inactive analogue SB202474 (data not shown). The activation of p38 MAPK in its phosphorylated form was confirmed in the CpG-DNA-treated PDC by a reprobing of the same membrane (Fig. 3B
, lower two). Neither the enhancement in IRF-7 expression nor the phosphorylation of p38 MAPK was induced by control oligo DNA 2GC (Fig. 3C)
. Taken together, these findings indicate that the p38 MAPK-mediated pathway is involved in CpG-DNA-induced IRF-7 expression and subsequent production of IFN-.
|
/ß gene induction [26
, 27
, 31
, 32
]. In PDC, two forms of IRF-3 were always recognized regardless of the treatment with CpG DNA. The slow-migrating band, which completely disappeared with alkali phosphatase treatment (data not shown), represented a phosphorylated/activated form of IRF-3 [33
]. The expression patterns remained almost unchanged by CpG-DNA treatment, which implied that IRF-3 was not only constitutively expressed but also already activated in part and that CpG-DNA treatment had no significant effect on IRF-3 activation. It appears that IRF-3 is not directly involved in CpG-DNA signaling in PDC.
As not only IRF-3 but also IRF-7 were constitutively expressed to some extent in freshly isolated PDC, we performed an IFN-/ß Ab-blocking test to examine whether CpG-DNA-induced IRF-7 augmentation is ascribed to a secondary response to the autocrine stimulation of IFN-/ß. However, the increase in IRF-7 expression was recognized even in the presence of IFN-/ß Ab (Fig. 3B) , suggesting that an IFN-/ß-independent pathway exists in CpG-DNA-enhanced IRF-7 expression in PDC. We then examined the time course of gene expression for IRF-7 and IFN-. As shown in Figure 4
, IRF-7 mRNA was constitutively expressed in PDC, and its expression gradually increased from 3 h on with the CpG-DNA treatment. Conversely, once the expression of IFN- mRNA was detected at 2 h, it rapidly diminished at 3 h and then increased thereafter. The transient expression of IFN- mRNA before the enhancement of IRF-7 seems to be caused by the activation of the constitutive IRF-7. However, IFN-/ß Ab and IFNAR Ab failed to reduce the IRF-7 enhancement and IFN- production, respectively (Figs. 2B
and 3B)
. Therefore, it is unlikely that the feedback signal of the early production of IFN- is responsible for the downstream pathway.
|
induces tyrosine phosphorylation of STAT1 by activating Janus kinase (JAK) associated with IFNAR2. Then, it induces heterodimer formation with STAT1 and STAT2, subsequently composing ISGF3 complex with IRF-9 [34
]. ISGF3 is the transcription factor not only for various cytokine-responsive genes but also for the IRF-7 gene [35
]. Conversely, Ser-727 phosphorylation of STAT1 is a key event in the responses induced by LPS, UV irradiation, or TNF- [36
, 37
] and in T cell activation by IL-12 and IL-2 [38
].
Regarding the IFN-/ß-independent process, we examined the effect of CpG DNA on STAT1 phosphorylation. In PDC, short-term (2 h) treatment with CpG DNA induced STAT1 tyrosine phosphorylation (Fig. 5A
). This was confirmed using BDCA-4+ PDC. In contrast, control oligo DNA 2GC did not induce STAT1 tyrosine phosphorylation. Ser-727 of STAT1 was already phosphorylated in PDC, and CpG DNA enhanced the phosphorylation from its constitutive level to a significant extent in each individual (e.g., 3.23-fold in Fig. 5B
and 1.61-fold in Fig. 6
, as analyzed by a densitometer). These phosphorylation patterns were not influenced by the pretreatment with anti-IFN-/ß Ab but were suppressed by SB203580, somehow, to a level below the control (Figs. 5B
and 6)
. It is interesting that although the stimulation with IFN- induced STAT1 phosphorylation not only on tyrosine but also on serine, they were not influenced by SB203580 (Fig. 6)
. These results indicate that CpG DNA induces tyrosine and serine phosphorylation of STAT1 via the p38 MAPK in an IFN-/ß-independent manner, and IFN--induced STAT1 phosphorylations are independent of p38 MAPK in PDC. They are also consistent with the result that SB203580 added in the later phase (at 10 h and more) showed a decreased, suppressive effect on IFN- production in CpG-DNA-treated PDC (Fig. 2)
.
|
|
/ß Ab, further supporting the direct action of CpG DNA toward STAT1 phosphorylation.
|
/ß-Ab treatment, thereby decreasing the nuclear translocation in the presence of the Ab. |
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
B, and production of IL-12 and TNF- [5
, 9
]. In humans, it has been recently reported that PDC selectively express TLR-9 and produce IFN- in response to CpG DNA [39
, 40
]. However, the mechanisms have not been clarified.
The CpG-DNA "polyG-flanked GACGATCGTC:g10gacga" that we used in this study is a potent inducer of IFN-, not only in humans but also in mice, and we observed that neither TLR-9- nor MyD88-deficient mice responded to this CpG DNA to produce IFN- (unpublished data). In addition, to maintain their intrinsic character, PDC were prepared by the depletion of lineage Ags+/CD11c+ cells from PBMC and were cultured in the absence of the maturation stimuli, such as IL-3 or CD40L. Therefore, the results obtained in our study seem to closely reflect the nature of circulating blood PDC. We have revealed here that CpG-DNA-induced IFN- production in PDC was associated with an enhancement of IRF-7 expression, which was preceded by STAT1 phosphorylation on tyrosine and serine residues. SB203580 suppressed CpG-DNA-induced IFN- production, IRF-7 enhancement, and phosphorylations of STAT1. Therefore, it is implied that p38 MAPK plays a key role in the CpG-DNA-induced IFN- production pathway in PDC.
We propose the mechanisms of CpG-DNA-induced IFN- production in PDC as illustrated in Figure 8
. CpG DNA introduced to the cells by binding to TLR-9 and/or endocytosis [5
] may give rise to the signals, including the activation of p38 MAPK. This induces the downstream phosphorylation of STAT1 on Tyr-701 and Ser-727, which would result in the formation of ISGF3 with STAT2 and IRF-9 to promote the transcription of the IRF-7 gene, and the newly produced and activated IRF-7 induces IFN- gene transcription. In addition to the pathway mentioned above, CpG DNA may provoke another cascade, i.e., the direct activation of the constitutively expressed IRF-7 to promote the transcription of the IFN- gene. This speculative view came about from the results that the nuclear translocation of constitutive IRF-7 (Fig. 7B)
and the IFN- gene expression were observed earlier than IRF-7 expression (Fig. 4)
. However, neither anti-IFN-/ß nor anti-IFNAR Ab inhibited STAT1 phosphorylation (Fig. 5B)
, IRF-7 enhancement (Fig. 3B)
, or IFN- production during the early phase (Fig. 2B) , and the IFN--inducing STAT1 phosphorylation was insensitive to SB203580 (Fig. 6)
. Therefore, it is implausible that the activation of constitutive IRF-7 triggers the CpG-induced IFN- production. It has been reported recently that in murine PDC, the virus-induced IFN- production occurs in the absence of IFNAR feedback signaling [41
]. PDC may display a unique characteristic in terms of the IFN--producing pathway, which is different from that in the mouse embryo fibroblasts where autocrine-IFN-/ß initiates virus-induced IFN- production [26
, 27
, 30
].
|
. Its expression may be maintained by a feedback signal of IFN-, which is released spontaneously to a level undetectable by ELISA in vitro.
As IRF-7 is known to be very unstable with a half-life within 1 h [26
], the constant promoting conditions may be necessary for long-lasting expression of IRF-7 and subsequent production of vast amounts of IFN-. In the later phase, secreted IFN- autocrinely stimulates IFN- signaling cascades via the JAK-STAT pathway [34
], which may contribute to the continuous activation of the IRF-7 gene through ISGF3 and finally to further IFN- production. The autocrine mechanism in the later phase was supported by the decreased responsiveness of PDC to SB203580 (Fig. 2A)
and the suppression of IFN- production by anti-IFNAR (Fig. 2B)
. As PDC have been reported to differentiate into mature DC by CpG-DNA stimulation [14
, 15
, 40
], the responsiveness against CpG DNA may have changed in the later phase.
This is the first study to demonstrate a unique pathway responsible for IFN- production in CpG-DNA-stimulated PDC in humans. However, the signaling pathway from TLR-9 to p38 MAPK-dependent phosphorylation of STAT1 remains unknown. The further elucidation of the mechanism of CpG-DNA-mediated IFN- production in PDC would be important for understanding the immune-defense system against bacterial infection as well as for constructing an effective vaccine adjuvant to control distinct adaptive immunity in humans.
|
ACKNOWLEDGEMENTS |
|---|
Received March 22, 2002; revised July 10, 2002; accepted July 29, 2002.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
/ß-producing cells link innate and adaptive immunity J. Exp. Med. 192,219-225
production in vitro J. Immunol. 163,3642-3652 genes in human fibroblast cells by ectopic interferon regulatory factor-7 J. Biol. Chem. 275,6313-6320/ß gene induction Immunity 13,539-548[Medline]
genes by positive feedback through interferon regulatory factor-7 EMBO J. 17,6660-6669[Medline]
/ß signal for efficient IFN-/ß gene induction by virus Biochem. Biophys. Res. Commun. 285,518-525[Medline]
uses a different signaling pathway Proc. Natl. Acad. Sci. USA 96,13956-13961This article has been cited by other articles:
|
|
 |
|
  A. F. Valledor, E. Sanchez-Tillo, L. Arpa, J. M. Park, C. Caelles, J. Lloberas, and A. Celada Selective Roles of MAPKs during the Macrophage Response to IFN-{gamma} J. Immunol., April 1, 2008; 180(7): 4523 - 4529. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Iparraguirre, J. W. Tobias, S. E. Hensley, K. S. Masek, L. L. Cavanagh, M. Rendl, C. A. Hunter, H. C. Ertl, Ulrich. H. von Andrian, and W. Weninger Two distinct activation states of plasmacytoid dendritic cells induced by influenza virus and CpG 1826 oligonucleotide J. Leukoc. Biol., March 1, 2008; 83(3): 610 - 620. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Berghofer, G. Haley, T. Frommer, G. Bein, and H. Hackstein Natural and Synthetic TLR7 Ligands Inhibit CpG-A- and CpG-C-Oligodeoxynucleotide-Induced IFN-{alpha} Production J. Immunol., April 1, 2007; 178(7): 4072 - 4079. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Fanning, T. C. George, D. Feng, S. B. Feldman, N. J. Megjugorac, A. G. Izaguirre, and P. Fitzgerald-Bocarsly Receptor Cross-Linking on Human Plasmacytoid Dendritic Cells Leads to the Regulation of IFN-{alpha} Production J. Immunol., November 1, 2006; 177(9): 5829 - 5839. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Osawa, S. Iho, R. Takauji, H. Takatsuka, S. Yamamoto, T. Takahashi, S. Horiguchi, Y. Urasaki, T. Matsuki, and S. Fujieda Collaborative Action of NF-{kappa}B and p38 MAPK Is Involved in CpG DNA-Induced IFN-{alpha} and Chemokine Production in Human Plasmacytoid Dendritic Cells J. Immunol., October 1, 2006; 177(7): 4841 - 4852. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. L. Shoenfelt and M. J. Fenton TLR2- and TLR4-dependent activation of STAT1 serine phosphorylation in murine macrophages is protein kinase C-{delta}-independent Innate Immunity, August 1, 2006; 12(4): 231 - 240. [Abstract] [PDF]
|
|
|
|
 |
|
 E. O. Kvale, J. Dalgaard, F. Lund-Johansen, H. Rollag, L. Farkas, K. Midtvedt, F. L. Jahnsen, J. E. Brinchmann, and J. Olweus CD11c+ dendritic cells and plasmacytoid DCs are activated by human cytomegalovirus and retain efficient T cell-stimulatory capability upon infection Blood, March 1, 2006; 107(5): 2022 - 2029. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. H. Han, J. H. Kim, H. S. Seo, M. H. Martin, G.-H. Chung, S. M. Michalek, and M. H. Nahm Lipoteichoic Acid-Induced Nitric Oxide Production Depends on the Activation of Platelet-Activating Factor Receptor and Jak2 J. Immunol., January 1, 2006; 176(1): 573 - 579. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Bendriss-Vermare, S. Burg, H. Kanzler, L. Chaperot, T. Duhen, O. de Bouteiller, M. D'agostini, J.-M. Bridon, I. Durand, J. M. Sederstrom, et al. Virus overrides the propensity of human CD40L-activated plasmacytoid dendritic cells to produce Th2 mediators through synergistic induction of IFN-{gamma} and Th1 chemokine production J. Leukoc. Biol., October 1, 2005; 78(4): 954 - 966. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Morita, T. Uchiyama, and T. Hori Nitric Oxide Inhibits IFN-{alpha} Production of Human Plasmacytoid Dendritic Cells Partly via a Guanosine 3',5'-Cyclic Monophosphate-Dependent Pathway J. Immunol., July 15, 2005; 175(2): 806 - 812. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. E. Mancl, G. Hu, N. Sangster-Guity, S. L. Olshalsky, K. Hoops, P. Fitzgerald-Bocarsly, P. M. Pitha, K. Pinder, and B. J. Barnes Two Discrete Promoters Regulate the Alternatively Spliced Human Interferon Regulatory Factor-5 Isoforms: MULTIPLE ISOFORMS WITH DISTINCT CELL TYPE-SPECIFIC EXPRESSION, LOCALIZATION, REGULATION, AND FUNCTION J. Biol. Chem., June 3, 2005; 280(22): 21078 - 21090. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Chung, S. B. Amrute, K. Abel, G. Gupta, Y. Wang, C. J. Miller, and P. Fitzgerald-Bocarsly Characterization of Virus-Responsive Plasmacytoid Dendritic Cells in the Rhesus Macaque Clin. Vaccine Immunol., March 1, 2005; 12(3): 426 - 435. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
