| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
-Inducing Signaling Pathways1
*
Department of Microbiology and Immunology and Walther Oncology Center, Indiana University School of Medicine, Indianapolis, IN 46202 and Walther Cancer Institute, Indianapolis, IN 46208;
Akdeniz University Tip Fakultesi, Tibbi Biyologi, Arapsuyu, Antalya, Turkey;
Tularik, Inc., San Francisco, CA 94080; and
§
Department of Cancer Biology, Harvard School of Public Health, and Department of Medicine, Harvard Medical School, Boston, MA 02115
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
, are compromised in the absence of
Stat4. Since the precise role of Stat4 in IFN- induction has not
been established, experiments were conducted to examine Stat4
activation of IFN- and other genes required for cytokine-induced
expression of IFN-. We first examined IL-12 signaling components.
Basal expression of IL-12Rß1 and IL-12Rß2 is decreased in
Stat4-deficient cells compared with that in control cells. However,
IL-12 was still capable of inducing equivalent phosphorylation of Jak2
and Tyk2 in wild-type and Stat4-deficient activated T cells. We have
further determined that other cytokine signaling pathways that induce
IFN- production are defective in the absence of Stat4. IL-18 induces
minimal IFN- production from Stat4-deficient activated T cells
compared with control cells. This is due to defective IL-18 signaling,
which results from the lack of IL-12-induced, and Stat4-dependent,
expression of the IL-18R. Following IL-12 pretreatment to induce
IL-18R, wild-type, but not Stat4-deficient, activated T cells
demonstrated IL-18-induced NF-
B DNA-binding activity. In addition,
IL-12-pretreated Stat4-deficient activated T cells have minimal IFN-
production followed by stimulation with IL-18 alone or in combination
with IL-12 compared with control cells. Thus, Stat4 activation by IL-12
is required for the function of multiple cytokine pathways that result
in induction of IFN-. |
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
production, proliferation of activated T
cells, increased cytotoxicity, and development of Th1 cells (8, 9). The precise role Stat4 plays in these responses is still
unclear.
Stat4 can interact directly with DNA sequences in the IFN- promoter
to increase gene transcription (10, 11), providing at
least one mechanism for IL-12-induced IFN- expression. However,
Stat4 may contribute to IFN- induction through other distinct
mechanisms as well. IL-12 can synergize with IL-18 (also called
IFN--inducing factor) to induce IFN-. IL-18 was cloned based on
its ability to induce the production of IFN- from T cells
(12). IL-18 is secreted by macrophages and dendritic cells
and is important for Th1 and NK function in vivo (13).
IL-18 signals follow interaction of cytokine with a specific receptor
composed of at least two separate chains, a cytokine-binding IL-18R
(originally identified as an IL-1R-related protein) and an accessory
protein-like chain,
AcPL3
(14, 15, 16, 17). IL-18 stimulation activates the DNA-binding
activity of both NF-B and AP-1 using signaling proteins that include
MyD88, TNFR-associated factor (TRAF) 6, IL-1R-associated kinase (IRAK),
and c-Jun N-terminal kinase (11, 18, 19, 20, 21, 22). The IL-18R chain
is differentially expressed on subsets of Th cells (23, 24), potentially as a result of IL-12 stimulation (25, 26). IL-1, which shares many signaling components with
IL-18, has also been shown to enhance Th1 development and IFN-
induction (27, 28). The function of these additional
IFN--inducing pathways in the absence of IL-12 signaling has not
been carefully examined.
Using previously generated Stat4-deficient mice that specifically lack
responses to IL-12, we have now determined that Stat4 contributes to
the regulation of IFN- production on several levels. In this report,
we demonstrate that expression of IL-12Rß1, IL-12Rß2, MyD88, and
IL-18R is IL-12 inducible in a Stat4-dependent manner. These results
suggest that in addition to direct affects on the IFN- gene, Stat4
regulates cytokine receptors and signaling pathways required for the
induction of IFN-.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The generation of Stat4-deficient mice was previously described (8). Mice were backcrossed 10 generations to the BALB/c background or eight generations to the C57BL/6 background. Mice were housed and bred in the Indiana University Laboratory Animal Research Center. Control BALB/c and C57BL/6 mice were purchased form Harlan Bioproducts (Indianapolis, IN). Mice used were between 6 and 12 wk of age.
Abs and cytokines
Anti-CD3 (145-2C11), anti-IL-4 (11B11), and anti-IFN-
(R4/6A2) were produced and purified in our laboratory. IL-12 was
purchased from Genzyme (Cambridge, MA). IL-18 was purchased from
PeproTech (Rocky Hill, NJ) or produced as recombinant protein in
Escherichia coli using the T7 system. IL-18 was expressed
with a C-terminal histidine tag and purified by nickel affinity
chromatography. IL-1
was provided by M. Harrington (Department of
Biochemistry, Indiana University School of Medicine).
Immunoprecipitations and phosphotyrosine analysis
Activated T cells were washed in medium and stimulated for 20 min in the absence or the presence of 2 ng/ml IL-12. Cells were immediately washed twice in cold serum-free RPMI 1640 and lysed in cold lysis buffer containing protease and phosphatase inhibitors. Protein concentrations of the extracts were determined, and Jak2 and Tyk2 were immunoprecipitated with purified rabbit polyclonal Abs (Santa Cruz Biotechnology, Santa Cruz, CA). Immunoprecipitates were separated by 7.5% SDS-PAGE and transferred to a nitrocellulose membrane. Immunoblotting was performed with a mouse monoclonal anti-phosphotyrosine Ab (Santa Cruz Biotechnology) and ECL detection kit (Amersham, Piscataway, NJ). Blots were stripped and reprobed with the precipitating Abs to demonstrate equal protein loading. Immunoblots of total cellular extracts were performed using polyclonal Abs to p65 and c-Rel (Santa Cruz Biotechnology).
IFN- assay
Total splenocytes were activated with 2 µg/ml plate-bound
anti-CD3 for 48 h at 2 x 106
cells/ml. Cells from mice with a BALB/c background were also incubated
with 10 µg/ml anti-IL-4 (11B11). Following activation, cells were
recovered, washed, replated at 106/ml, and left
unstimulated or stimulated with 1 ng/ml IL-12, doses of IL-18 as
indicated, or both for 48 h. In some experiments activated cells
were pretreated with 2 ng/ml IL-12 for 18 h before additional
stimulation as described above. Cell-free supernatants were
collected, and IFN- levels were determined by ELISA (PharMingen, San
Diego, CA).
Proliferation assay
Splenocytes were activated as described above, washed, and plated in a microtiter plate at 105/ml. Cells were incubated in the presence or the absence of IL-12 and the concentrations of IL-18 indicated. Cells were pulsed with 1 µCi of [3H]thymidine/well for the last 18 h of a 48-h incubation.
Gel shift analysis
CD4+ cells were purified from 48-h
anti-CD3 activated splenocytes by magnetically removing
B220+ (PharMingen), CD8+
(2.43), Fc receptor+ (2.4G2), and MHC class
II+ cells using a mixture of mAbs and goat
anti-rat magnetic beads (PerSeptive Biosystems, Framingham, MA).
Cells were then treated for 18 h with 2 ng/ml IL-12, washed, and
plated at 5 x 106/ml in the presence or the
absence of 50 ng/ml IL-18 for 1 h. Whole cell extracts were made
by lysing cells in 5 mM HEPES, 100 mM KCl, 0.125 M EDTA, 0.025 EGTA,
0.25 mM DTT, 0.25 mM MgCl2, 5% glycerol, 0.25%
Nonidet P-40, and protease inhibitors. Extract protein concentrations
were determined, and equal amounts of protein were used for each
binding reaction. Gel shifts used oligonucleotides specific for AP-1
(11) and NF-B (Promega, Madison, WI).
Northern blot analysis
Splenocytes were activated as described above, and Th1 or Th2 cultures were generated as previously described (29). Cells were washed, plated at 5 x 106/ml, and incubated in the presence or the absence of IL-12 for 4 h. RNA was isolated using Trizol (Life Technologies, Gaithersburg, MD) and run on a denaturing formaldehyde agarose gel. Northern blots were probed with cDNAs labeled with random decamer reagents (Ambion, Austin, TX). Probes for IRAK and TRAF6 were provided by M. Harrington (Department of Biochemistry, Indiana University School of Medicine), and IL-18 R was supplied by J. Sims (Immunex, Seattle, WA). The MyD88 coding sequence probe was generated by PCR using 5'-TGAATTCATGTCTGCGGGAGACCCCCGCGTGGGATCCGGGTC-3' and 5'-TTCCTCGAGTCAGGGCAGGGACAAAGCCTTGGCAAGGCGGGTCCAG-3'. Underlined segments denote restriction enzyme site added to coding sequence. The AcPL probe was generated by PCR using specific primers (5'-ATGCTCTGTTTGGGCTGGGTGTTTC-3' and 5'-CTTCCATCCTTGTACCAGGTCATCTC-3'). IL-12R probes were generated by PCR (ß1, 5'-TGAAGACGGCGCGTGGGAGTCA-3' and 5'-TCGCGGGTACAACACCTCCGGG-3'; ß2, 5'-GGCACAGACTGTTAGAGAATGCTC-3' and 5'-TGCAGA-AGCGCCTTTTGAGTTGGC-3'). cDNA was generated using a cDNA synthesis kit (Roche, Indianapolis, IN). All PCR-generated probes were subcloned and sequenced to verify identity.
Statistics
Statistical analysis was performed using a two-tailed Student’s t test.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
To determine the role of Stat4 in IFN- induction, we first
assessed mRNA expression of IL-12R chains. Wild-type and
Stat4-deficient spleen cells were activated for 48 h with 2
µg/ml plate-bound anti-CD3, washed, and incubated for 4 h in
the absence or the presence of 2 ng/ml of IL-12. Total RNA was isolated
from cells and subjected to Northern blot analysis. Fig. 1
demonstrates that IL-12Rß1 and
IL-12Rß2 expression is decreased in the absence of Stat4. Since
IFN- is known to induce and IL-4 is known to decrease, IL-12Rß2
expression (30), it seemed possible that the reduced level
of IL-12Rß2 expression on Stat4-deficient cells was due to a lack of
IFN- or an increase in IL-4 produced in the Stat4-deficient
cultures. To test this, we then supplemented medium during the
activation period with 500 U/ml IFN- and 10 µg/ml anti-IL-4.
Expression of either IL-12R chain was not affected by supplementation
of anti-CD3-stimulated cultures with IFN- and neutralizing IL-4
Ab (data not shown). This suggests that the defect in IL-12R expression
in the Stat4-/- cells is not due to a lack of
IFN- and agrees with a previous report that anti-CD3 induced
IFN- is not decreased in Stat4-deficient cultures (9).
Fig. 1 also demonstrates that IL-12Rß1 and IL-12Rß2 are induced by
IL-12 in a short term stimulation in wild-type, but not in
Stat4-deficient, cultures. The induction of IL-12R expression is modest
(1.3-fold for IL-12Rß1 and 1.5-fold for IL-12Rß2), but is abolished
in the absence of Stat4 when expression is normalized to TCR
expression (Fig. 1B). These results suggest that Stat4 may
also function directly at the IL-12R promoters and demonstrate that
Stat4 is required for the normal expression of IL-12R chains following
T cell activation.
|
shows that IL-12 is equally
capable of stimulating phosphorylation of Jak2 and Tyk2 in wild-type
and Stat4-deficient cells.
|
induction by other cytokines
Several cytokines, including IL-1 and TNF-, alone and in
combination with IL-12, function to induce IFN- (27, 28). The ability of IL-1 and TNF- to induce IFN-
production and to synergize with IL-12 is diminished in the absence of
Stat4 (data not shown). However, the amounts of IFN- induced by
these stimuli, even in control activated T cell populations, are small.
The ability of IL-18 to induce IFN- expression and synergize with
IL-12 is more dramatic. To determine whether IL-18 induced IFN-
expression was similarly dependent on Stat4, we tested the function of
IL-18 on wild-type and Stat4-deficient cells. Total splenocytes from
wild-type and Stat4-deficient mice were activated with 2 µg/ml
plate-bound anti-CD3 for 48 h. Activated cells were then
washed and plated for an additional 48 h in the absence or the
presence of increasing doses of IL-18. Fig. 3A demonstrates that wild-type
cells produce an IL-18 dose-dependent increase in IFN- production.
In contrast, Stat4-deficient cells produced little IFN- in the
absence or the presence of IL-18. To demonstrate that the synergy with
IL-12 was also affected by Stat4 deficiency, cells activated as
described above were washed and plated for an additional 48 h in
the absence or the presence of 1 ng/ml IL-12, 50 ng/ml IL-18, or both
cytokines. IL-12 stimulated a 10- to 20-fold increase in IFN-
production over that seen in unstimulated wild-type cultures (Fig. 3B). Strikingly, the combination of both cytokines led to a
severalhundred-fold increase in secreted IFN- levels. There was
no significant increase in IFN- production following IL-18
stimulation of Stat4-deficient activated T cells. Furthermore the
induction of IFN- secretion by a combination of both cytokines was
greatly diminished in Stat4-deficient cultures (Fig. 3B).
The increase in IFN- production in IL-12- and IL-18-treated
Stat4-deficient cells may be attributed to synergy between
Stat4-independent IL-12 signals, such as the activation of p38
mitogen-activated protein kinase (31), and limited IL-18
signaling. The lack of IL-18 responsiveness was observed in Stat4/Stat6
double-deficient cells and Stat4-deficient purified B cells in addition
to activated T cells from both the BALB/c and C57BL/6 genetic
backgrounds (Fig. 3 and data not shown). Together, these data support a
requirement for Stat4 in IL-18 responses.
|
induction, IL-18 has also been shown to induce a proliferative response
in activated T cells (23, 26). To test whether the lack of
IL-18 responsiveness described in the IFN- induction assay above was
specific for the IFN- gene or was a more generalized phenomenon, we
examined the proliferative responses to IL-18 or the combination of
IL-12 and IL-18 of wild-type and Stat4-deficient activated T cells.
Wild-type T cells displayed a significant increase in proliferation
following stimulation with IL-18 (Fig. 3
C). IL-12 also
stimulated an increase in proliferation that was enhanced by the
addition of IL-18. Strikingly, Stat4-deficient cultures showed no
significant increase in proliferation in response to IL-18 alone or in
combination with IL-12 (Fig. 3C). Thus, the inability of
Stat4-deficient lymphocytes to respond to IL-18 is not restricted to
IFN- gene expression. IL-18 signaling in the absence of Stat4
It has already been shown that IL-18 does not activate Stat4
itself (19). To investigate the mechanism of IL-18
unresponsiveness in Stat4-deficient activated T cells, we examined the
expression of genes involved in IL-18 signaling. We performed Northern
blot analysis using RNA from wild-type and Stat4-deficient T cells
activated as described above and incubated for 4 h in the absence
or the presence of IL-12. Expressions of IRAK and TRAF6 were equivalent
in both wild-type and Stat4-deficient cells, with no apparent induction
by IL-12 (Fig. 4A). The IL-18R
accessory protein, AcPL, was expressed at equivalent or slightly higher
levels in Stat4-deficient cells compared with wild-type cells. There
was an induction of MyD88 expression (2-fold) following IL-12
stimulation of wild-type cells, consistent with the identification of a
Stat binding site in the MyD88 promoter (32). Importantly,
the IL-18R (previously termed IL-1R-related protein) showed
Stat4-dependent induction by IL-12 and dramatically lower levels of
expression in Stat4-deficient cells, suggesting that it may be a
crucial component of Stat4-dependent IL-18 responsiveness.
|
B). In contrast, Stat4-deficient T cells had barely
detectable expression of IL-18R that was not affected by treatment of
the cells with IL-12 and IL-18 (Fig. 4B). As previously
described (23, 24), IL-18R was not expressed in Th2 cells
(Fig. 4B).
To further demonstrate decreased IL-18 signaling in the absence of
Stat4, CD4+ cells from wild-type and
Stat4-deficient mice were activated for 48 h with anti-CD3 as
described above. Activated T cells were then incubated with IL-12 for
18 h to induce IL-18R expression, washed, and cultured in the
presence or the absence of IL-18 for 1 h. Total cellular extracts
were then used in an EMSA with probes for the IL-18-activated
transcription factor NF-B. In wild-type cells there was a 3.5-fold
increase in the binding activity of NF-B following stimulation with
IL-18 (Fig. 5). In contrast,
Stat4-deficient cells had a lower basal level of NF-B-binding
activity. Importantly, IL-18 did not induce DNA-binding activity in
Stat4-deficient T cells. To confirm equivalent expression of
transcription factors present in the NF-B complex, we performed
Western blot analysis for p65 and c-Rel in the extracts described
above. There was no appreciable difference in the expression of p65 or
c-Rel between wild-type and Stat4-deficient T cells (Fig. 5 and data
not shown). This further demonstrates that there is an IL-18 signaling
defect that occurs in the absence of Stat4.
|
, we tested these cells
for IFN- secretion as shown in Fig. 3A. Fig. 6A demonstrates that
IL-12-pretreated Stat4-deficient activated T cells produce minimal
IFN- in response to increasing doses of IL-18, while wild-type cells
were sensitized to IL-18 by IL-12 pretreatment and secreted levels of
IFN- even higher than those shown in Fig. 3A. This
sensitivity was also displayed when IL-12-pretreated wild-type cells
were stimulated with IL-12 and IL-18 and cells secreted high levels of
IFN-. No significant increase in IFN- secretion was observed in
IL-12-pretreated Stat4-deficient cultures following treatment with
IL-12 and IL-18.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
production. This observation may be
attributed at least in part to Stat4 binding directly to the IFN-
promoter resulting in increased gene transcription (10, 11). This report further demonstrates that Stat4 is required for
IL-18-induced IFN- expression. This may occur through several
distinct mechanisms. First, the IL-12-induced expression of MyD88 may
affect signaling from the IL-18R (Fig. 4). Second, Stat4 regulates
IL-18R expression that directly affects cellular responses to IL-18
(Fig. 4). Stat4 may also regulate genes other than those identified
here that are involved in IL-18 signaling or the synergy between IL-12
and IL-18. Stat4 regulation of IFN- may also include interactions
between Stat4- and IL-18-induced transcription factors such as NF-B
or AP-1 at the IFN- promoter. Indeed, IL-18-activated NF-B has
been shown to be important in IFN- induction (33).
Thus, Stat4 may act as a gateway, both directly and indirectly
controlling expression of IFN-.
The reduced level of expression of both IL-12R chains in
Stat4-deficient cells was surprising, and Stat4 may regulate their
expression through distinct mechanisms. IL-12Rß2 expression is
up-regulated by anti-CD3 signaling, although the exact signaling
requirements are not clear. Jnk2 appears to play an indirect role in
anti-CD3-induced IL-12Rß2 induction. In Jnk2-deficient mice,
inefficient up-regulation of the IL-12Rß2 chain results in decreased
Th1 development (34). However, supplementation of
Jnk2-deficient cells with IFN- recovers Th1 differentiation,
suggesting that anti-CD3 induced IFN- is required for the
induction of IL-12Rß2 expression (34). Our results
suggest that IL-12R expression requires both IFN- and IL-12
signaling to achieve normal levels, since IFN- alone did not recover
IL-12R expression in the absence of Stat4. Indeed, an IL-12-dependent,
IFN--independent, up-regulation of the IL-12Rß2 chain has been
described (35). In this report we further show that
IL-12-induced IL-12Rß1 and IL-12Rß2 expression is Stat4 dependent.
Importantly, Stat4-dependent IL-12R expression does not appear to be
strictly required for IL-12 signaling, since IL-12 induces normal
levels of Jak2 and Tyk2 phosphorylation in the absence of Stat4 (Fig. 2). Nevertheless, Stat4-induced IL-12R expression may be required to
increase IL-12 responsiveness in some biological settings.
In many ways IL-18R expression parallels IL-12Rß2 expression. Both
receptor chains appear as T cells are activated to differentiate.
IL-18R and IL-12Rß2 are expressed on Th1, but not on Th2, cells
(23, 24, 30). The obvious functional consequence is that
differentiated Th1 cells become more susceptible to IFN--inducing
signals. Our report reveals a positive regulatory loop, in that IL-12,
via Stat4, can increase expression of its own receptor and the receptor
for IL-18. Furthermore, Stat4 is required for IL-18R expression in
differentiated Th1 cells. IL-18 is an important regulator of NK and Th1
responses (13, 17). Thus, the defects in Stat4-deficient
mice, and potentially in IL-12- and IL-12R-deficient patients
(36, 37, 38), reflect not only deficiencies in IL-12
signaling, but IL-18 signaling as well.
IL-12-stimulated biological functions require Stat4. However, the role
of Stat4 in many of these responses has not been precisely determined.
In this report we found that Stat4 regulates several genes that are
required for signaling pathways leading to induction of the IFN-
gene. This is in addition to the direct effects Stat4 has on the
IFN- gene itself. Thus, in eliciting the effects of IL-12, Stat4
very likely has direct and indirect roles in generating and regulating
immune responses. Understanding the role of Stat4 will require further
investigation into novel aspects of IL-12 biology and further
identification of Stat4 target genes.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Mark H. Kaplan, The Walther Oncology Center, Indiana University School of Medicine, 1044 West Walnut Street, Room 302, Indianapolis, IN 46202.
3 Abbreviations used in this paper: AcPL, accessory protein-like chain; TRAF, TNFR-associated factor; IRAK, IL-1R-associated kinase.
Received for publication March 17, 2000. Accepted for publication September 20, 2000.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
promoter in primary CD4+ T lymphocytes. J. Immunol. 160:3642. production by T cells. Nature 378:88.[Medline]
B in murine Th1 cells. Biochem. Biophys. Res. Commun. 234:454.[Medline]
production and activates IRAK and NF-B. Immunity 7:571.[Medline]
-inducing factor (IGIF) is a costimulatory factor on the activation of Th1 but not Th2 cells and exerts its effect independently of IL-12. J. Immunol. 158:1541.[Abstract]
-inducing factor in enhanced production of IFN-. J. Immunol. 159:2125. production. J. Immunol. 161:3400. and TNF- are required for IL-12 induced development of Th1 cells producing high levels of IFN-gamma in BALB/c but not C57BL/6 mice. J. Immunol. 160:1708. expression. J. Immunol. 165:1374.B in IL-18-induced IFN- expression in KG-1 cells. J. Immunol. 162:5063. secretion and not restricted to T and NK cells. J. Immunol. 163:5257.This article has been cited by other articles:
|
|
 |
|
  Y. Cao, P. D. Doodes, T. T. Glant, and A. Finnegan IL-27 Induces a Th1 Immune Response and Susceptibility to Experimental Arthritis J. Immunol., January 15, 2008; 180(2): 922 - 930. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Miyagi, M. P. Gil, X. Wang, J. Louten, W.-M. Chu, and C. A. Biron High basal STAT4 balanced by STAT1 induction to control type 1 interferon effects in natural killer cells J. Exp. Med., October 1, 2007; 204(10): 2383 - 2396. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. R. Wickstrum, K.-J. Hong, S. Bokhari, N. Reed, N. McWilliams, R. T. Horvat, and M. J. Parmely Coactivating Signals for the Hepatic Lymphocyte Gamma Interferon Response to Francisella tularensis Infect. Immun., March 1, 2007; 75(3): 1335 - 1342. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. S. Berenson, M. Gavrieli, J. D. Farrar, T. L. Murphy, and K. M. Murphy Distinct Characteristics of Murine STAT4 Activation in Response to IL-12 and IFN-{alpha} J. Immunol., October 15, 2006; 177(8): 5195 - 5203. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Tortorella, I. Stella, G. Piazzolla, V. Cappiello, O. Simone, A. Pisconti, and S. Antonaci Impaired Interleukin-12-Dependent T-Cell Functions During Aging: Role of Signal Transducer and Activator of Transcription 4 (STAT4) and Suppressor of Cytokine Signaling 3 (SOCS3). J. Gerontol. A Biol. Sci. Med. Sci., February 1, 2006; 61(2): 125 - 135. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. M. Wozniak, A. A. Ryan, J. A. Triccas, and W. J. Britton Plasmid Interleukin-23 (IL-23), but Not Plasmid IL-27, Enhances the Protective Efficacy of a DNA Vaccine against Mycobacterium tuberculosis Infection Infect. Immun., January 1, 2006; 74(1): 557 - 565. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. J. Boyton, S. Davies, C. Marden, C. Fantino, C. Reynolds, K. Portugal, H. Dewchand, and D. M. Altmann Stat4-null non-obese diabetic mice: protection from diabetes and experimental allergic encephalomyelitis, but with concomitant epitope spread Int. Immunol., September 1, 2005; 17(9): 1157 - 1165. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. J. Robertson, H.-C. Chang, D. Pelloso, and M. H. Kaplan Impaired interferon-{gamma} production as a consequence of STAT4 deficiency after autologous hematopoietic stem cell transplantation for lymphoma Blood, August 1, 2005; 106(3): 963 - 970. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Lund, Z. Chen, J. Scheinin, and R. Lahesmaa Early Target Genes of IL-12 and STAT4 Signaling in Th Cells J. Immunol., June 1, 2004; 172(11): 6775 - 6782. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. A. Papadakis, J. L. Prehn, C. Landers, Q. Han, X. Luo, S. C. Cha, P. Wei, and S. R. Targan TL1A Synergizes with IL-12 and IL-18 to Enhance IFN-{gamma} Production in Human T Cells and NK Cells J. Immunol., June 1, 2004; 172(11): 7002 - 7007. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Toyoda, M. Ido, T. Hayashi, E. C. Gabazza, K. Suzuki, J. Bu, S. Tanaka, T. Nakano, H. Kamiya, J. Chipeta, et al. Impairment of IL-12-Dependent STAT4 Nuclear Translocation in a Patient with Recurrent Mycobacterium avium Infection J. Immunol., March 15, 2004; 172(6): 3905 - 3912. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. O'Sullivan, H.-C. Chang, Q. Yu, and M. H. Kaplan STAT4 Is Required for Interleukin-12-induced Chromatin Remodeling of the CD25 Locus J. Biol. Chem., February 20, 2004; 279(8): 7339 - 7345. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P.-H. Chiang, L. Wang, C. A. Bonham, X. Liang, J. J. Fung, L. Lu, and S. Qian Mechanistic Insights into Impaired Dendritic Cell Function by Rapamycin: Inhibition of Jak2/Stat4 Signaling Pathway J. Immunol., February 1, 2004; 172(3): 1355 - 1363. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Wang, N. S. Ostlie, B. M. Conti-Fine, and M. Milani The Susceptibility to Experimental Myasthenia Gravis of STAT6-/- and STAT4-/- BALB/c Mice Suggests a Pathogenic Role of Th1 Cells J. Immunol., January 1, 2004; 172(1): 97 - 103. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. M. Monick, L. Samavati, N. S. Butler, M. Mohning, L. S. Powers, T. Yarovinsky, D. R. Spitz, and G. W. Hunninghake Intracellular Thiols Contribute to Th2 Function via a Positive Role in IL-4 Production J. Immunol., November 15, 2003; 171(10): 5107 - 5115. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Lafont, S. Loisel, J. Liautard, S. Dudal, M. Sable-teychene, J.-P. Liautard, and J. Favero Specific Signaling Pathways Triggered by IL-2 in Human V{gamma}9V{delta}2 T Cells: An Amalgamation of NK and {alpha}{beta} T Cell Signaling J. Immunol., November 15, 2003; 171(10): 5225 - 5232. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Freudenberg, C. Kalis, Y. Chvatchko, T. Merlin, M. Gumenscheimer, and C. Galanos Role of interferons in LPS hypersensitivity Innate Immunity, October 1, 2003; 9(5): 308 - 312. [Abstract] [PDF]
|
|
|
|
|
|
H.-C. Chang, S. Zhang, I. Oldham, L. Naeger, T. Hoey, and M. H. Kaplan STAT4 Requires the N-terminal Domain for Efficient Phosphorylation J. Biol. Chem., August 22, 2003; 278(34): 32471 - 32477. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Lugo-Villarino, R. Maldonado-Lopez, R. Possemato, C. Penaranda, and L. H. Glimcher T-bet is required for optimal production of IFN-{gamma} and antigen-specific T cell activation by dendritic cells PNAS, June 24, 2003; 100(13): 7749 - 7754. [Abstract] [Full Text] [PDF]
|
|
|
|
|
