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Prepublished online as a Blood First Edition Paper on September 5, 2002; DOI 10.1182/blood-2002-05-1327.
IMMUNOBIOLOGY
From the Laboratory of Molecular Growth Regulation,
National Institute of Child Health and Human Development, and
Laboratory of Parasite Diseases, National Institute of Allergy and
Infectious Diseases, National Institutes of Health (NIH), Bethesda, MD;
and Immunobiology Laboratory, Cancer Research United Kingdom, London
Research Institute, London, United Kingdom.
Dendritic cells (DCs) develop from bone marrow (BM)
progenitor cells and mature in response to external signals to elicit functions important for innate and adaptive immunity. Interferon consensus sequence binding protein (ICSBP; also called interferon regulatory factor 8 [IRF-8]) is a hematopoietic
cell-specific transcription factor expressed in BM progenitor cells
that contributes to myeloid cell development. In light of our earlier
observation that ICSBP Dendritic cells (DCs) develop from bone marrow (BM)
progenitor cells and mature in response to external
signals.1,2 Previous efforts to dissect DC heterogeneity
led to the classification of murine DCs into the CD8 Despite much progress in understanding the biology of DCs, molecular
events that specify DC development are still largely unknown. It is not
clear what transcription factors are involved in multiple steps of DC
development. Similarly, little is known regarding the mechanisms
controlling the expression of genes important for DC function,
including IL-12 and major histocompatability complex (MHC) class II.
Several transcription factors have been shown to contribute to DC
development. For example, mice with a dominant-negative
Ikaros gene lack both CD8 Interferon consensus sequence binding protein (ICSBP; also
called interferon regulatory factor 8 [IRF-8]) is a
DNA-specific transcription factor that belongs to the IRF
family.15 It is expressed only in the hematopoietic cells
including lineage-negative BM cells, as well as macrophages and
lymphocytes.16,17 ICSBP interacts with partner proteins to
bind to well-studied target elements, interferon-stimulated response
element (ISRE) and Ets-IRF composite element (EICE), and
regulates gene expression in the immune system.16,18 ISRE
is present in many interferon-inducible genes and is the target element
for all IRF proteins. EICE is a composite element for ICSBP and PU.1
and is found in many genes active in the immune cells.16
ICSBP-null mice develop a leukemialike disease19 and are susceptible to infection by a variety of
pathogens.20-23 The high susceptibility to pathogens is
accounted for by the inability of ICSBP The present study investigates the development of
ICSBP Mice
DC preparation and culture
Retroviral transduction Full-length ICSBP cDNA was ligated into the EcoRI site of pMSCV-EGFP28 to construct pMSCV-ICSBP-EGFP. Retroviral pMSCV vectors harboring the wild-type ICSBP and mutants 1-390, 1-356, and Lys79Glu (K79E) were described.25 Mutants Ser258Ala (S258A) and Arg289Glu (R289E) were generated by site-directed mutagenesis using QuikChange (Stratagene, La Jolla, CA). BM cells were incubated in the complete medium for 1 day followed by spinoculations on 2 consecutive days. Cells were incubated with retrovirus containing supernatants supplemented with 4 µg/mL polybrene. Twenty-four hours after the second spinoculation, cells were cultured for an additional 6 days. Cells transduced with pMSCV vectors containing the wild-type and mutant ICSBP were selected by 0.5 µg/mL puromycin for 5 days starting 2 days after spinoculation.Flow cytometry Specific antibodies used for flow cytometry (all purchased from BD Pharmingen, San Diego, CA) include fluorescein isothiocyanate (FITC)-conjugated antibodies against CD11c (HL3), phycoerythrin (PE)-conjugated antimouse CD8 (Ly-2),
I-Ab (Ab), CD80 (B7-1), CD40 (3/23), or Flt3
(Ly-72). For IL-12 intracellular staining, cells pretreated with 10 µg/mL of brefeldin A (Sigma) for 2 hours were stained for CD11c and
fixed with 2% paraformaldehyde in phosphate-buffered saline (PBS).
Cells were permeabilized with 0.5% saponin (Sigma), and stained with
allophycocyanin (APC)-conjugated antimouse IL-12 (p40/p70). Stained
cells were collected on FACSCaliber (Becton Dickinson, San Jose,
CA) and data were analyzed by FlowJo software (Tree Star, San
Carlos, CA).
ELISA and MLRs DCs (2 × 105 cells in 200µL) generated in vitro were stimulated with or without LPS, CpG, or STAg for 24 hours. IL-12 p40 in supernatants was measured by an enzyme-linked immunosorbent assay (ELISA) using a kit (BD Pharmingen).For mixed leukocyte reactions (MLRs), increasing numbers of in
vitro-generated and irradiated CD11c+ DCs
(0.3 × 103 to 1 × 104) were incubated
with 1 × 105 BALB/c splenic lymphocytes in 100 µL
media for 3 days and pulsed with 0.5 µCi (0.0185 MBq)
[3H]thymidine (TdR; Amersham,
Piscataway, NJ) for 8 hours. 3H-TdR incorporation
was measured on a RT-PCR Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was performed for indicated transcripts as described.25 For real-time PCR, amplification of sample cDNA was monitored with the fluorescent DNA-binding dye SYBR Green (DNA Master SYBR Green I kit, Roche, Indianapolis, IN) in combination with the LightCycler system (Roche), according to the manufacturer's instructions. Transcript levels were normalized by hypoxanthine-guanine phosphoribosyltransferase (HPRT) levels. Primer sequences used for PCR are available on request.Immunofluorescent staining CD11c+ DCs were placed on coverslips (Becton Dickinson) and fixed with 4% paraformaldehyde and permeabilized by 0.5% saponin. Cells were incubated with goat anti-ICSBP IgG (Santa Cruz Biotechnology, Santa Cruz, CA) followed by FITC antigoat IgG (Jackson Immuno Research, West Grove, PA). Stained cells were viewed with a confocal microscope (Leica).EMSA In vitro transcription/translation (IVT) of ICSBP and partners as well as an electrophoretic mobility shift assay (EMSA) were performed as described.25
Defects of ICSBP  / mice are deficient in CD8+
DCs, although they have normal numbers of CD8
DCs.26 We observed that ICSBP/ splenic DCs
(CD8) in vivo do not induce CD40, CD80, and MHC class
II molecules after injection of LPS or CpG, indicating that the defects
of ICSBP/ DCs are not restricted to CD8 expression,
but extend to functions and even to a maturation step. In an effort to
better define the defects in ICSBP/ DCs and elucidate
the role of ICSBP in DC development, we used an Flt3L-based culture
system.27 In this system, BM progenitor cells
differentiate into immature DCs in about 9 days and on maturation, about 25% of cells are induced to express CD8. Prior to this study
we confirmed that ICSBP/ lineage-negative BM progenitor
cells express Flt3 at levels comparable to ICSBP+/+ cells
(not shown), making this culture system suitable for studying ICSBP/ DC development. Following 9 days of culture in
the presence of Flt3L, ICSBP/ and ICSBP+/+
BM cells gave rise to a similar number of cells
(1-3 × 106 cells/plate). About 90% of cells derived
from ICSBP+/+ BM cultures were CD11c+ and
showed typical DC morphology as described,27 whereas about 60% of cells from ICSBP/ BM cultures were
CD11c+, which appeared monocytelike with fewer
dendrites. On LPS stimulation, ICSBP+/+ cells
attained features characteristic of mature DCs. However, ICSBP/ cells did not show changes indicative of DC maturation.
Figure 1A depicts flow cytometry analysis
of CD8
The lack of IL-12 production by ICSBP /
macrophages do not express IL-12 p40,25 we were interested in determining whether ICSBP/ DCs also fail to express
the gene. BM-derived DCs were stimulated with LPS, CpG, or STAg for 24 hours and expression of IL-12 p40 mRNA was examined by
semiquantitative RT-PCR. Before stimulation, ICSBP+/+ DCs
expressed IL-12 p40 mRNA at a low level, followed by a marked increase
on stimulation by all 3 agents. Similarly, CD8 transcripts were
increased after stimulation in ICSBP+/+ cells. In contrast,
neither IL-12 p40 nor CD8 transcripts were detectable in
ICSBP/ DCs before or after stimulation.
To establish that IL-12 p40 transcript induction results in the
production of IL-12 protein in ICSBP+/+ DCs, LPS-stimulated
DCs were stained for intracellular IL-12. As shown in Figure 2B, about
25% of ICSBP+/+ DCs were positive for IL-12 protein on LPS
treatment, although few cells expressed the protein before treatment.
In contrast, less than 2% of ICSBP Impaired allogeneic MLR by ICSBP / DCs (both
H-2b) were cocultured with BALB/c (H-2d) spleen
lymphocytes for 3 days and the proliferative responses were measured by
3H-TdR uptake. As shown in Figure 2D, ICSBP+/+
cells treated with LPS exhibited the highest amount of
3H-TdR incorporation. Although about 3 times less
efficient, untreated ICSBP+/+ cells also led to significant
levels of 3H-TdR incorporation. However,
ICSBP/ cells, even after LPS treatment, led to a modest
3H-TdR uptake. These results indicate that
ICSBP/ DCs are defective in stimulating MLRs.
Retroviral ICSBP transduction restores DC development from
ICSBP / BM progenitor cells, we first used an MSCV-based
retrovirus vector expressing ICSBP and green fluorescent protein (GFP;
ICSBP-EGFP in Figure 3). As a control, a
vector that expresses GFP only (EGFP in Figure 3) was tested. Fresh
ICSBP/ BM cells were transduced with the vectors in the
presence of Flt3L. Flow cytometry analysis in Figure 3A depicts
expression of surface markers on GFP+ and GFP
cells. The former represented transduced cells, whereas the latter represented untransduced cells. When cells were transduced with control
vector, the percentage of CD11c+ cells remained unchanged
from untransfected cells. These cells also did not express CD8
before and after LPS, as expected. In contrast, when cells were
transduced with the ICSBP-EGFP vector, the percentage of
CD11c+ cells markedly increased both before and after LPS.
Significantly, about 12% of these cells expressed CD8 after LPS
stimulation. Further confirming CD8 induction, the MFI for CD8
was increased by more than 3-fold in ICSBP-EGFP-transduced cells
(Figure 3B). Both constitutive and LPS-inducible expression of MHC
class II molecules, defective in ICSBP/ DCs, was
restored following ICSBP-EGFP transduction to a level comparable to
ICSBP+/+cells. Likewise, CD80 expression was increased on
ICSBP-GFP transduction to ICSBP+/+ DC levels before and
after LPS stimulation. In contrast, cells expressing GFP only did not
restore the expression of any of these molecules. Transduction of
ICSBP-EGFP vector into ICSBP+/+ BM cells led to a slight
increase in CD8, without affecting MHC class II and CD80 levels,
which were already very high before transduction (not shown).
Thus, simple reintroduction of ICSBP into ICSBP/ BM
progenitors restores expression of CD8 and other surface molecules
on DCs generated in vitro, indicating that ICSBP has an important role
in promoting DC development/maturation.
Exogenously expressed ICSBP restores IL-12 p40 production To further investigate the effect of ICSBP reintroduction on DC development, we used another retroviral vector that harbored a puromycin-resistant gene. The use of this vector allowed us to select transduced cells, eliminating untransduced cells from the culture. Immunofluorescent staining in Figure 4A shows that ICSBP/ DCs transduced with the ICSBP virus
expressed the ICSBP protein in the nucleus, although the level of
expression appeared lower than that of untransduced
ICSBP+/+ DCs. Cells transduced with control vector did not
show a detectable ICSBP staining, as expected. Moreover, cells
transduced with the ICSBP vector underwent morphologic transformation
consistent with proper DC differentiation (Figure 4B); these cells
developed many long dendrites on LPS stimulation, similar to
ICSBP+/+ DCs. However, cells transduced with control vector
developed fewer and shorter dendrites.
We then investigated whether ICSBP can restore IL-12 p40 expression in
ICSBP Identification of ICSBP domains required for restoration of DC development To address the mechanism by which ICSBP rescues DC development and confers the ability to mature, we examined several ICSBP mutants (Figure 5A). ICSBP carries the DNA-binding domain (DBD) in the N-terminal region involved in the binding to target DNA elements, the ISRE and EICE.16 It also has the IRF association domain (IAD) in the C-terminal region involved in the interaction with partner proteins, including IRF-1, IRF-2, and PU.1.16,25 Binding of ICSBP to target DNA is dependent not only on the intact DBD but an interaction with a specific partner, in that it can bind to the ISRE, if it interacts with IRF-1 or IRF-2, whereas it can bind to the EICE when interacting with PU.1.16 Mutant 1-390 is a truncation lacking the C-terminal 34 amino acids. This mutant retains the DNA-binding activity, interacts with partners, and similar to the wild-type ICSBP, is capable of stimulating transcription and macrophage differentiation.17,25 However, Lys79Glu, having a point mutation in the DBD, does not bind to target elements and is defective in transcription and in stimulating macrophage differentiation. Similarly, 1-356, lacking the critical region in the IAD, does not interact with partners, fails to bind to either target DNA, and thus is functionally defective.25 Besides these mutants, 2 additional mutants, Ser258Ala and Arg289Glu, were constructed and tested in this work. Both Ser258Ala and Arg289Glu harbor a point mutation in the IAD. Serine at 258, equivalent to the serine at 260 of the human ICSBP, is thought to be functionally important because it is phosphorylated through the association with the CSN2 in theCOP9/signalosome complex.30 Arginine at 289, located in an helix of the IAD, is highly conserved at equivalent positions in
several IRF IADs and is believed to be indispensable for interaction
with PU.1.31 These residues are replaced by alanine and
glutamic acid, respectively. By EMSAs, we first examined whether new
mutants Ser258Ala and Arg289Glu can form a complex with a partner and
bind to the ISRE and EICE. Figure 5B depicts IVT products indicating
proteins of expected size. In Figure 5C, EMSAs were performed and
tested for the 2 target elements. ISRE binding was examined with
wild-type or mutant ICSBP along with IRF-2, whereas EICE binding was
tested along with PU.1. Wild-type ICSBP, but not mutant Lys79Glu run as
a control, produced an ICSBP/IRF-2 complex on ISRE, and ICSBP/PU.1
complex on EICE, as expected. The lower bands with arrowhead indicate binding of IRF-2 or PU.1 alone.25 Mutant Arg289Glu did not
form a complex with either partner and failed to bind to either target, indicating the critical importance of arginine in this position for
partner interaction and DNA binding. Interestingly, mutant Ser258Ala
interacted with both partners and bound to both target elements,
suggesting that this residue is dispensable for partner interaction and
DNA-binding activities.
These mutants were cloned in the puromycin-resistant vector and
introduced into ICSBP ICSBP stimulates MHC class II gene expression through a DC-specific CIITA promoter The observation that the ICSBP-EGFP vector increased MHC class II surface expression (Figure 4) implied that ICSBP regulates MHC class II transcript expression. This possibility was interesting because it has previously been shown that MHC class II expression induced by interferon (IFN-) is normal in ICSBP/ peritoneal
macrophages.18 In the left panel of Figure
6A, levels of MHC class II transcripts
(I-Ab) were tested by real-time PCR for
ICSBP+/+ and ICSBP/ DCs generated in vitro.
Constitutive levels of class II transcripts were about 10-fold higher
in ICSBP+/+ cells than ICSBP/ cells.
Stimulation by LPS or IFN- did not significantly change transcript
levels. As shown in the right panel of Figure 6A, transduction of the
wild-type ICSBP or 1-390 vector led to an approximate 4-fold increase
in the constitutive expression of MHC class II transcripts compared
with cells transduced with the control vector. In contrast, no increase
in MHC class II mRNA levels was seen with the mutants 1-356 and
Lys79Glu. These results indicate that ICSBP plays an important role in
the expression of MHC class II genes in DCs.
Constitutive and IFN- TLR signaling in ICSBP and IL-12 p40 genes was
defective in ICSBP/ DCs, but rescued by ICSBP
transduction, it seemed possible that this transcription factor is
required for proper LPS signaling in DCs. LPS and other microbial
products are recognized by a series of TLRs. Their signaling is
mediated through the adaptor protein MyD88, resulting in the activation
of transcription factor nuclear factor- B
(NF-B).35,36 Although NF-B is a major target of TLR-MyD88 mediated signaling, evidence indicates that MyD88 stimulates other transcription pathways as well.37 In addition, a
recent study indicates that LPS triggers DC maturation through
MyD88-dependent and -independent pathways.38 To gain
insight into the role of ICSBP in LPS signaling, we examined TLR
expression in ICSBP/ DCs generated in vitro. Expression
of TLR4 and TLR2 transcripts was tested because LPS signaling is shown
to be largely dependent on TLR4,36,39 but TRL2 may also
participate in LPS signaling.40 As shown in Figure
7A, TLR4 transcripts were constitutively
expressed and down-regulated 3 and 8 hours after LPS stimulation both
in ICSBP+/+ and ICSBP/ cells. The
down-regulation of TLR4 has been reported for LPS-treated macrophages
and likely represents LPS tolerance.41 TLR2 transcripts were also constitutively expressed and slightly increased after LPS
addition both in ICSBP+/+ and ICSBP/ cells.
MyD88 transcripts were also expressed in ICSBP/ DCs at
levels comparable to those in ICSBP+/+ DCs. Normal
expression of TLRs and MyD88 as well as the down-regulation of TLR4 by
LPS suggested that TLR signaling is intact in ICSBP/
DCs. To further assess the functionality of TLR4 signaling in ICSBP/ DCs, we examined IB transcript induction.
IB induction is an event that follows the degradation of IB that
is associated with the activation of NF-B. It represents a feedback
mechanism to restore IB levels following NF-B
activation.42 In real-time PCR analysis shown in Figure
7B, IB transcripts were induced within 1 hour after LPS
stimulation both in ICSBP+/+ and ICSBP/ DCs
at comparable levels, indicating that NF-B activation is not
impaired in ICSBP/ DCs. These results indicate that the
TLR-MyD88 signaling pathway is intact in ICSBP/ DCs and
is activated on LPS stimulation, suggesting that ICSBP functions along
with the pathway, but acting separately from NF-B.
Disruption of the ICSBP gene causes specific defects in
DC development in vivo; it eliminates CD8 ICSBP confers CD8 / DCs were devoid of both
CD8 mRNA and the surface protein, and that both were induced on
ICSBP transduction, indicating that ICSBP regulates CD8 gene
expression in DCs, thereby contributing to the development of a
CD8+ subset. Given our previous results that ICSBP plays
a role in lineage selection during myeloid cell
development,17,25 it is possible that ICSBP acts in the
common myeloid progenitor that gives rise to CD8+ and
CD8 DCs. Although the functional significance of
CD8 expression in DCs is not completely elucidated, CD8
expression may simply reflect stages of DC
maturation.7,9,10 The finding that CD8 expression was
seen only after LPS stimulation in our culture system may be consistent
with these observations and may support plasticity of CD8
expression. Nevertheless, previous studies with mutant mice with
disrupted genes11-13 as well as those correlating CD8
expression and distinct functions3,5,6,43 may support the
alternative possibility that CD8 expression reflects separate pathways of DC differentiation, to which ICSBP contributes.
ICSBP confers IL-12 p40 expression It was striking that ICSBP/ DCs lacked IL-12 p40
expression under all conditions tested, before and after stimulation,
but the defects were fully corrected after ICSBP transduction alone. Our findings suggest that ICSBP is a factor obligatory to the transcription of IL-12 p40 in DCs and that the restoration of mRNA
expression suffices the production and secretion of the protein. An
analogous situation has been observed with ICSBP/
macrophages, in that IL-12 p40 transcripts are absent in
ICSBP/ macrophages and introduction of ICSBP vectors
rescues the expression of endogenous IL-12 p40 mRNA and stimulates
IL-12 p40 reporter activity.18,25 Thus, it appears that
ICSBP is essential for IL-12 p40 expression both in DCs and
macrophages, although this does not exclude the contribution of other
transcription factors such as NF-B.44 In any event,
given the fact that IL-12 production is a critical aspect of DC
function regulating the development of Th1 or Th2 cells,29
ICSBP seems to have a vital role in broadly influencing the nature of
immune responses.
Mechanism of ICSBP action By EMSA analysis, ICSBP mutants tested in this work were classified into 2 groups, ones that formed a complex with partners and bound to the ISRE and EICE targets, and the others that failed to do so. Whereas those in the former group fully restored DC development/maturation, those in the latter group completely failed to do so, showing perfect concordance between the ability to induce DC development/maturation and to act as a transcription factor. None of the mutants showed an intermediate phenotype in terms of both DNA/partner binding and restoration of DC development. These results indicate that ICSBP induces DC development/maturation by directly regulating target genes critical for DC development rather than acting indirectly along differentiation pathways. Target genes necessary for promoting DC development may carry either ISRE, EICE, or related sequences in the promoter. EICE and like elements are found in a series of genes important for macrophage and DC functions.45,46 The ISRE is also found in some genes important for innate immunity.47 Target genes activated by ICSBP may extend beyond genes carrying a classic ISRE or EICE, because ICSBP is shown to regulate gene expression through other elements.18,48 Our results also underscore the importance of partner proteins, without which ICSBP does not function. Consistent with this, PU.1, a partner for EICE binding has been shown to be involved in DC development as well as expression of genes important for innate immunity.13,14 It is interesting to note here that mutant Ser258Ala, lacking a CSN2 phosphorylation site30 retained DNA/partner-binding activity and fully restored DC development, indicating that the CSN2-mediated phosphorylation is not essential for DC development/maturation.Role for ICSBP in MHC class II expression Among cell surface markers whose expression was defective in ICSBP/ DCs, but rescued by the ICSBP reintroduction,
MHC class II warrants some discussion, because unlike what was observed
with ICSBP/ DCs, ICSBP/ macrophages
express MHC class II antigens normally on stimulation with IFN-,
indicating that the lack of ICSBP does not affect MHC class II
expression in macrophages.18 Here we found that constitutive MHC class II expression is significantly lower in ICSBP/ DCs than ICSBP+/+ cells, suggesting
that ICSBP regulates class II genes in DCs, but not in macrophages.
Pertinent to this issue, it has previously been shown that class II
transactivator CIITA is differentially regulated in various cell types
and that its transcription in DCs is specifically controlled by
promoter I.33 We have shown that promoter I-driven CIITA
transcript expression is defective in ICSBP/ DCs, but
is rescued following ICSBP retrovirus transduction, with a concomitant
restoration of MHC class II expression in these cells. Thus, ICSBP
regulates MHC class II transcription in DCs by controlling promoter
I-specific CIITA transcription.
TLR signaling and ICSBP DC maturation is triggered by the engagement of TLRs and is mediated by the adaptor MyD88.35,36 Although NF-B is a
key downstream transcription factor activated by this signaling
pathway, the recent report analyzing MyD88/ mice
indicates that the TLR-MyD88 signaling can act through pathways independent of NF-B.37 In this context it is
interesting to note that BM-derived DCs from MyD88/
mice do not induce IL-12 p40 in response to LPS, suggesting that LPS
induction of IL-12 p40 requires MyD88 signaling.38 We have shown that the TLR-MyD88 signaling pathway is functional in
ICSBP/ DCs, as evidenced by the expected
down-regulation of TLR4 and induction of IB following
LPS stimulation. In view of the shared defect between
MyD88/ and ICSBP/ DCs in inducing IL-12
p40, it seems plausible that ICSBP works downstream of the MyD88
signaling pathway, presumably acting separately from NF-B.
In conclusion, ICSBP is an integral part of the developmental program
specifying the differentiation of both CD8
We thank Dr R. Germain for critical reading of the manuscript. Drs S. Uehara, P. Love, T. Uno, T. McCarty, D. Klinman, and H. Shingh are gratefully acknowledged for advice on flow cytometry, help in construction of ICSBP mutants, the real-time PCR procedure at an initial stage, and reagents.
Submitted May 6, 2002; accepted August 26, 2002.
Prepublished online as Blood First Edition Paper, September 5, 2002; DOI 10.1182/blood-2002-05-1327.
Supported by the Japan Society for the Promotion of Science (JSPS) Research Fellowships for Japanese Biomedical and Behavioral Researchers at the National Institutes of Health (H.T.).
The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked "advertisement" in accordance with 18 U.S.C. section 1734.
Reprints: Keiko Ozato, Bldg 6, Rm 2A01, Laboratory of Molecular Growth Regulation, National Institute of Child Health and Human Development, National Institutes of Health, 6 Center Dr MSC 2753, Bethesda MD 20892; e-mail: ozatok{at}nih.gov.
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  U. Martin, J. Scholler, J. Gurgel, B. Renshaw, J. E. Sims, and C. A. Gabel Externalization of the Leaderless Cytokine IL-1F6 Occurs in Response to Lipopolysaccharide/ATP Activation of Transduced Bone Marrow Macrophages J. Immunol., September 15, 2009; 183(6): 4021 - 4030. [Abstract] [Full Text] [PDF]
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H. J. Kong, D. E. Anderson, C. H. Lee, M. K. Jang, T. Tamura, P. Tailor, H. K. Cho, J. Cheong, H. Xiong, H. C. Morse III, et al. Cutting Edge: Autoantigen Ro52 Is an Interferon Inducible E3 Ligase That Ubiquitinates IRF-8 and Enhances Cytokine Expression in Macrophages J. Immunol., July 1, 2007; 179(1): 26 - 30. [Abstract] [Full Text] [PDF]
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N. Nakano, C. Nishiyama, S. Kanada, Y. Niwa, N. Shimokawa, H. Ushio, M. Nishiyama, K. Okumura, and H. Ogawa Involvement of mast cells in IL-12/23 p40 production is essential for survival from polymicrobial infections Blood, June 1, 2007; 109(11): 4846 - 4855. [Abstract] [Full Text] [PDF]
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D. Yadav and N. Sarvetnick B7-2 Regulates Survival, Phenotype, and Function of APCs J. Immunol., May 15, 2007; 178(10): 6236 - 6241. [Abstract] [Full Text] [PDF]
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F. Mattei, G. Schiavoni, P. Borghi, M. Venditti, I. Canini, P. Sestili, I. Pietraforte, H. C. Morse III, C. Ramoni, F. Belardelli, et al. ICSBP/IRF-8 differentially regulates antigen uptake during dendritic-cell development and affects antigen presentation to CD4+ T cells Blood, July 15, 2006; 108(2): 609 - 617. [Abstract] [Full Text] [PDF]
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C. H. Lee, M. Melchers, H. Wang, T. A. Torrey, R. Slota, C.-F. Qi, J. Y. Kim, P. Lugar, H. J. Kong, L. Farrington, et al. Regulation of the germinal center gene program by interferon (IFN) regulatory factor 8/IFN consensus sequence-binding protein J. Exp. Med., January 23, 2006; 203(1): 63 - 72. [Abstract] [Full Text] [PDF]
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T. Tamura, P. Tailor, K. Yamaoka, H. J. Kong, H. Tsujimura, J. J. O'Shea, H. Singh, and K. Ozato IFN Regulatory Factor-4 and -8 Govern Dendritic Cell Subset Development and Their Functional Diversity J. Immunol., March 1, 2005; 174(5): 2573 - 2581. [Abstract] [Full Text] [PDF]
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S. Suzuki, K. Honma, T. Matsuyama, K. Suzuki, K. Toriyama, I. Akitoyo, K. Yamamoto, T. Suematsu, M. Nakamura, K. Yui, et al. From the Cover: Critical roles of interferon regulatory factor 4 in CD11bhighCD8{alpha}- dendritic cell development PNAS, June 15, 2004; 101(24): 8981 - 8986. [Abstract] [Full Text] [PDF]
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H. Tsujimura, T. Tamura, H. J. Kong, A. Nishiyama, K. J. Ishii, D. M. Klinman, and K. Ozato Toll-Like Receptor 9 Signaling Activates NF-{kappa}B through IFN Regulatory Factor-8/IFN Consensus Sequence Binding Protein in Dendritic Cells J. Immunol., June 1, 2004; 172(11): 6820 - 6827. [Abstract] [Full Text] [PDF]
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M. Schmidt, J. Bies, T. Tamura, K. Ozato, and L. Wolff The interferon regulatory factor ICSBP/IRF-8 in combination with PU.1 up-regulates expression of tumor suppressor p15Ink4b in murine myeloid cells Blood, June 1, 2004; 103(11): 4142 - 4149. [Abstract] [Full Text] [PDF]
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G. Schiavoni, F. Mattei, P. Borghi, P. Sestili, M. Venditti, H. C. Morse III, F. Belardelli, and L. Gabriele ICSBP is critically involved in the normal development and trafficking of Langerhans cells and dermal dendritic cells Blood, March 15, 2004; 103(6): 2221 - 2228. [Abstract] [Full Text] [PDF]
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T. Tamura, H. J. Kong, C. Tunyaplin, H. Tsujimura, K. Calame, and K. Ozato ICSBP/IRF-8 inhibits mitogenic activity of p210 Bcr/Abl in differentiating myeloid progenitor cells Blood, December 15, 2003; 102(13): 4547 - 4554. [Abstract] [Full Text] [PDF]
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H. Tsujimura, T. Tamura, and K. Ozato* Cutting Edge: IFN Consensus Sequence Binding Protein/IFN Regulatory Factor 8 Drives the Development of Type I IFN-Producing Plasmacytoid Dendritic Cells J. Immunol., February 1, 2003; 170(3): 1131 - 1135. [Abstract] [Full Text] [PDF]
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Top
Abstract
Introduction
-plate counter.
) denotes MLR by
ICSBP+/+ fresh BM mononuclear cells. Values are shown as
means ± SDs.
) dendritic cell subset by a maturation process involving CD8alpha, DEC-205, and CD24 up-regulation.
Blood.
2002;99:999-1004