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B Activity in T Lymphocytes from Patients with Systemic Lupus Erythematosus Is Associated with Decreased p65-RelA Protein Expression1 ,2
Departments of
*
Cellular Injury and
Medicine, Walter Reed Army Institute of Research, Washington, DC 20307;
Department of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814;
Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157.
 |
Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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B contributes to the
transcription of numerous inflammatory genes and has been shown to be a
molecular target of antiinflammatory drugs, we sought to characterize
the functional role of the NF-B protein complex in lupus T cells.
Freshly isolated T cells from lupus patients, rheumatoid arthritis (RA)
patients, and normal individuals were activated physiologically via the
TCR with anti-CD3 and anti-CD28 Abs to assess proximal membrane
signaling, and with PMA and a calcium ionophore (A23187) to bypass
membrane-mediated signaling events. We measured the NF-B binding
activity in nuclear extracts by gel shift analysis. When compared with
normal cells, the activation of NF-B activity in SLE patients was
significantly decreased in SLE, but not in RA, patients. NF-B
binding activity was absent in several SLE patients who were not
receiving any medication, including corticosteroids. Also, NF-B
activity remained absent in follow-up studies. In supershift
experiments using specific Abs, we showed that, in the group of SLE
patients who displayed undetectable NF-B activity, p65 complexes
were not formed. Finally, immunoblot analysis of nuclear extracts
showed decreased or absent p65 protein levels. As p65 complexes are
transcriptionally active in comparison to the p50 homodimer, this novel
finding may provide insight on the origin of abnormal cytokine or other
gene transcription in SLE patients. |
Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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production (12), and
activation-induced cell death (13).
Another defect that has been well described in T cells is the deficient
synthesis of IL-2 when T cells are stimulated by mitogens
(14, 15, 16, 17). The mechanism for this defect at the molecular
level remains unclear. IL-2 production is regulated predominantly at
the transcriptional level and requires signaling through the TCR and
the CD28 costimulatory molecule (18, 19, 20, 21, 22). Transcription
factors that participate in inducing the synthesis of IL-2 mRNA
include: AP-1, NF-AT, and NF-B (19, 23). Although all
three transcription factors contribute in the activation of IL-2, in
primary human T cells, NF-B has been shown to be an important factor
in initiating the transcriptional response to TCR and CD28 ligation,
expression of IL-2, and proliferation (24, 25, 26, 27).
The transcription factor NF-B is pervasive in immune tissues and
plays an important function in the regulation and the development of
the immune response through the regulation of cytokines and cell
surface markers (reviewed in Refs. 28, 29, 30, 31). The
NF-B/Rel protein family has many members and consists of DNA binding
proteins that interact to form dimers with one another through a region
termed the Rel homology domain. The Rel domain is a highly conserved
300-aa region that mediates protein-protein interaction and DNA
binding. There are five genes for the NF-B/Rel family in humans:
NF-B1 (p50), NF-B2 (p52), RelA, cRel, and Rel B. These factors
mediate nuclear responses to a wide variety of inducers, such as
cytokines, bacterial products, viral products, apoptotic signals, and
other forms of cellular stress. NF-B binding sites can be identified
in the promoter region of numerous genes that are activated in response
to TCR ligation, including IL-2 (19), GM-CSF(28, 29), IL-4
(30), and FasL (31).
The critical role of NF-B in T cell activation and IL-2 production
can best be seen in transgenic mice that have homologous deletion of
genes for specific NF-B subunits. These mice display impaired T cell
activation and low levels of IL-2, supporting the vital function of the
NF-B family in T cell function (32).
Although the T cell effector dysfunction seen in SLE can be a direct
consequence of surface membrane-initiated signaling abnormalities,
altered nuclear transcription factor expression may add to the
immunopathogenesis of the disease. Because IL-2 is one of the earliest
cytokines expressed after TCR ligation, and the nuclear factors that
regulate IL-2 production have been identified, we sought to understand
the regulation of NF-B in lupus and conducted experiments to
investigate the regulation of the NF-B pathway in SLE T cells. Our
results show that SLE T cells display defective inducible forms of
NF-B activity.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Peripheral blood was donated by volunteers after informed consent was obtained from normal and diseased individuals according to protocols approved by the source institutions as per Walter Reed Army Medical Center Human Use Committee protocol 3727-98. PBMC were separated from RBC on Lymphoprep gradient (Nycomed Pharma, Oslo, Norway), as recommended by the manufacturer. T cells were separated subsequently by rosetting with neuraminadase-treated SRBC by incubating PBMC and SRBC at 4°C overnight, followed by further separation of T cells by centrifugation on Lymphoprep gradient. Rosetted T cells were centrifuged and washed with PBS. SRBC were removed by incubating for 5 min in ACK lysing buffer (0.15 M NHqCl, l mM KHCO3 0.1 mM EDTA), followed by dilution with five times excess RPMI. T cells were washed and separated by centrifugation at 1400 x g, and the cells were resuspended in RPMI 10% FCS and rested for 18 h at 37°C before stimulation. The purified cells are >95% positive for CD3. Immediately before stimulation, cells were washed in fresh RPMI 10% FCS and resuspended in a 1-ml volume with the appropriate activating agent. The volume was brought up to 5 ml, and cells were incubated for the remaining time after stimulation at 37°C in a 5% CO2 incubator.
Antibodies
Abs to NF-B subunits were purchased from Santa Cruz
Biotechnology (Santa Cruz, CA): anti-p50 Ab, anti-p52 Ab,
anti-c-Rel Ab, anti-p65 (RelA) N-terminal Ab, anti-p65
(RelA) C-terminal Ab, and anti-RelB Ab. Anti-CD3 (OKT3) was
purchased from Ortho Biotech (Rantan, NJ), and anti-CD28 Ab was
purchased from PharMingen (San Diego, CA).
Protein immunoblotting
Western blot analysis was performed as described by Harlow and Lane (33). A total of 15 µg of protein extracts was denatured at 95°C in 2x laemmli buffer for 2 min and loaded onto 10% Trig glycine SDS gel (Novex, San Diego, CA) and electrophoresed at 125 V constant. Protein was transferred to Immobilon polyvinylidene difluoride membrane (Millipore, Bedford, MA) in transfer buffer at 14 V for 3 h. The membranes were washed in PBS and blocked with PBS + 3% dry milk for 1 h and incubated in primary Ab (1:1000 dilution) for 2 h. The membrane was then washed in PBS for 5 min with three changes of buffer, reblocked for 1 h, and then probed with secondary Ab at 1:1000 dilution for 1 h. The membrane was washed in PBS + 0.05% Tween six times for 5 min each, and the bands of interest were visualized by chemiluminescence (Pierce, Rockford, IL.).
Protein isolation
At least 10 million T cells were used for preparation of extracts for each experimental point. T cells following treatment with appropriate stimulus were washed three times in PBS, and cells were extracted for protein essentially as described (34). Cells were resuspended in buffer A (10 mM HEPES-KOH (pH 7.9) at 4°C, 1.5 mM MgCl2, 10 mM KCl) with protease inhibitor mixture (1 µM PMSF, 1 µM DTT, 2 µg/µl leupeptin, 1 µg/ml aprotinin, 5 mM NaF, 1 mM sodium vanadate) at a concentration of 200 µl per 10 million cells. Cells were incubated for 15 min on ice and centrifuged at 1000 x g. The cell pellets were then resuspended in buffer B (20 mM HEPES-KOH (pH 7.9), 25% glycerol, 420 mM NaCl, 1.5 mM MgCl2, 0.2 mM EDTA with protease inhibitor mixture) and incubated for 30 min on ice followed by brief sonication and centrifugation at 15,000 rpm in microfuge for 30 min at 4°C. The supernatant was collected and the protein concentration quantified using Bio-Rad (Richmond, CA) protein assay. The protein extract was then stored at -80°C until needed for EMSA and Western blot analysis.
EMSA
Double-stranded B oligos,
5'-gatcccaacggcaggggaattcccctctcctta and the complement strand, were
custom synthesized from Life Technologies (Grand Island, NY). The B
oligonucleotides were end-labeled with
[
-32P]ATP (NEN/DuPont, Boston, MA) using T4
polynucleotide kinase (Boehringer Mannheim, Indianapolis, IN).
Unincorporated label was separated using Sephadex G50 (Pharmacia
Biotech, Piscataway, NJ) spin column. For binding reaction, 15000 cpm
of radiolabeled B oligonucleotide was incubated with 1 µg of
lymphocyte protein extract in binding buffer in the presence of 1 µg
poly(dI-dC) (Sigma, St. Louis, MO) as nonspecific competitor. The
reaction mixture was incubated for 15 min at room temperature and
loaded on 5% nondenaturing polyacrylamide gel in 0.5x
Tris-borate-EDTA buffer. The gel was then dried under vacuum on
blotting paper and the protein DNA complexes visualized by
autoradiography.
Data analysis
For analysis of the optical density of the band for NF-B,
autoradiograms were scanned with a Hewlett-Packard (Palo Alto, CA)
scanner and analyzed using the National Institutes of Health Image
program version 1.61. The relative optical density on the autoradiogram
was recorded, and statistically significant differences were determined
by the Mann-Whitney U test and the Kruskal-Wallis test.
Statistical significance comparing treated patients to untreated
patients was determined by the one-way ANOVA.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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B is defective in SLE T cells
After stimulation through the TCR using anti-CD3 and
anti-CD28 mAbs, efficient activation of NF-B activity can be
readily detected in primary T cells isolated from the peripheral blood
by EMSA (Fig. 1
A). Stimulation
solely through the TCR by anti-CD3 mAb did not effectively activate
NF-B, as shown in Fig. 1A. The development of doublet
bands, which disappear in the presence of excess unlabeled B
oligonucleotide, demonstrate the specificity of DNA binding by NF-B.
Time course experiments determined the optimal time for the detection
of NF-B in primary T cells to be 6 h after stimulation.
Although NF-B was activated after 3 h (5-fold), greater levels
of DNA binding were consistently detected at 6 h (5.5- to 7-fold).
This activation of the NF-B is best followed by the slower migrating
upper band, which disappears when competed with an excess of unlabeled
B-specific oligonucleotide (Fig. 1A).
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B binding activity following stimulation with
anti-CD3/anti-CD28 mAbs. NF-B binding activity, as
determined by EMSA in nine SLE patients, displayed both qualitative and
quantitative differences when compared with that seen in normal T cells
(Fig. 1
B). The intensity, when measured by densitometry, of
the upper band was >2 SD below the normal mean in five patients (SLE4,
SLE18 shown in Fig. 1, A and D), decreased, as
defined by an intensity between 1 and 2 SD below the normal mean, in
four patients (SLE6 and SLE19 in Fig. 1C). The lower band,
which is also specific for NF-B binding, was similar in stimulated
and unstimulated T cells in both normal and SLE T cells (Fig. 1, A, C, and D).
To determine whether the observed decreased NF-B binding activity
was limited to SLE patients, T cells from eight patients with
rheumatoid arthritis (RA) were analyzed. All protein extracts from RA T
cells showed detectable upper bands for NF-B, albeit of less
intensity than normal T cells in certain RA patients (Fig. 1D). Also, T cells from patients with a low-grade T cell
malignancy (cutaneous T cell lymphoma) did not show abnormal NF-B
activation (data not shown).
Activation of NF-B in SLE T cells with PMA and A23187
It has been shown previously that certain TCR-mediated signaling
events, such as increases in intracytoplasmic calcium (3)
and tyrosine phosphorylation (4), are abnormal in lupus T
cells. To determine whether the novel abnormality in NF-B activation
in SLE patients was the result of defective initiation of signaling at
the cell surface through the Ag receptor and CD28 receptors, PMA and
the calcium ionophore, A23187, which activate in normal T cells NF-B
through intracellular second messenger pathways, were used to assess
the activation of NF-B in SLE T cells (Fig. 2A).
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B binding
activity. As shown in Fig. 2B, a defect in NF-B
activation was seen when compared with normals. Out of 18 patients
analyzed, the intensity of the upper band was >2 SD below the normal
mean in nine patients, between 1 and 2 SD below the normal mean in
seven patients, and within 1 SD of the normal mean in two patients.
This finding suggests that a defect in the regulation of NF-B
binding activity resided downstream from the surface signaling
machinery. In certain lupus individuals, T cells were stimulated by
both methods, either with anti-CD3/anti-CD28 mAbs or
PMA/A23187. The levels of induced NF-B binding activity when
stimulated by these two methods were always found to be concordant in
an SLE patient (Fig. 2C).
Defective NF-B activation in SLE T cells is not the result of
abnormal kinetics of activation
We considered the possibility that abnormal induction of NF-B
in SLE T cells may reflect aberrant kinetics of NF-B activation. The
anti-CD3 mAb-mediated increased tyrosine phosphorylation in lupus T
cells has been shown to reach peak levels earlier than in normal T
cells (4). Therefore, we tested whether SLE T cells, which
displayed abnormal activation when stimulated with PMA/A23187 or
anti-CD3/anti-CD28 mAbs, showed abnormal kinetics of NF-B
activation. Fig. 3 shows the NF-B
binding activity in SLE T cells at times 0, 3, and 6 h after
initiation of stimulation. The B binding activity remained absent
throughout the time period analyzed. In contrast, the level of NF-B
seen in normal lymphocyte extracts was rapidly induced and remained
stable over the time course that was studied.
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NF-B is composed of five genetically distinct family members
that, through protein-protein interactions, form homo- or heterodimers
that constitute B DNA binding activity (35). To define
the NF-B abnormality in SLE T cells, we added Abs specific to
various members of the NF-B family in the EMSA binding reaction with
SLE extracts. As shown in Fig. 4, only
the p50 subunit is detected by DNA binding assays in extracts isolated
from unstimulated normal T cells, whereas the other NF-B family
members are not detected as part of the DNA binding complex (Fig. 4).
When T cells were stimulated, p50 homodimer, p65(RelA)-p50 heterodimer
and p65(RelA) homodimer complexes formed, which appeared as doublet
bands. The p50 homodimers constitute the faster migrating band, and the
slower, upper band is composed of p50-p65 heterodimers (Fig. 4) or p65
homodimers, as determined by the addition of specific Abs to the
binding reaction. Anti-p50 Ab disrupted the presence of the lower band
and led to the appearance of a new slower migrating band, which is
consistent with the shifted larger complex. Anti-p65 Ab specifically
eliminates the presence of the upper band because the Ab that binds
this subunit is incompatible with DNA binding in EMSA. Other members
that constitute NF-B activity, such as p52 and RelB, are
predominantly expressed in accessory cells, such as dendritic cells and
macrophages, and, as shown in Fig. 4, these proteins were not detected
in nuclear extracts from normal T cells using subunit-specific
Abs.
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B subunit was abnormally
regulated in SLE, specific Abs for NF-B subunits were added to the
binding reaction in EMSA. Similar to unstimulated T cells from normal
individuals, the p50 component of NF-B was supershifted in the
presence of anti-p50 Ab. However, compared with normal T cells, a
profound lack of the p65 DNA binding activity was found in SLE T cells
when analyzed with anti-p65 Ab (Fig. 4). The Abs specific for the
other NF-B members failed to alter the NF-B binding pattern in
lupus cells, which is consistent with their absence in the NF-B
binding activity in normal and lupus cells.
Defect in NF-B binding activity is due to decreased p65 protein
The lack of p65 DNA binding activity in EMSA assays in SLE T cells
could reflect modifications of the p65 subunit that affect its ability
to dimerize with other family members and bind DNA. Alternatively, it
is possible that the p65 protein may exist in an inactive form and is
either unable to bind DNA or is inhibited by a repressor. To
distinguish among these possibilities, immunoblotting of whole
lymphocyte proteins transferred to polyvinylidene difluoride membrane
was performed using Abs specific to p50 and p65. Fig. 5A demonstrates that the level
of p50 in extracts from SLE T cells did not vary from one patient to
another and was quantitatively comparable to extracts from normal and
RA controls. In addition, the level of p50 in each individual did not
change after stimulation with anti-CD3/anti-CD28 mAbs or
PMA/A23187.
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B). Similarly, the p65 levels were markedly decreased in
SLE individuals (SLE12 and SLE14) with decreased DNA binding activity.
In contrast, the intensity of p65 band in RA patients was
quantitatively comparable to that of normal controls. Using protein
extracts from the same patients and controls, we reassessed the levels
of p65 with another anti-p65 Ab that recognizes the C terminus of
the protein (Fig. 5C). We again noted the absence of the p65
protein in SLE T cells that lack DNA binding activity. These results
suggest that there is an abnormality in the expression of the p65
subunit in SLE patients and that it is associated with decreased/absent
NF-B binding activity. In contrast, p65 protein was detected in
lysates from PBMC from SLE patients, suggesting that the defect was
limited to T cells (data not shown).
Levels of NF-B binding activity in SLE patients remain stable
over time
To determine whether the lack of NF-B activity in lupus
patients is a transient abnormality or is stable property, protein
extracts from the same individuals were obtained at different times,
and the p50/p65 NF-B binding activity was quantified. The time
intervals between the initial and subsequent analysis of NF-B in
each SLE patient varied from 1 to 15 mo. As shown in Fig. 6, the NF-B binding activity remained
stable over time and never approached the level exhibited by normal
individuals. The level of NF-B activity over time remained
significantly lower than the average of the level of normals
(p < 0.005) (Fig. 6).
|
To assess the relative defect in the level of NF-B in the group
of SLE patients tested in comparison to normal volunteers and RA
patients and to eliminate interexperimental variation, all extract
samples were assayed simultaneously under identical EMSA conditions
using labeled B probes. The level of p65 induction was scanned from
the autoradiographic films that were subjected to the same length of
exposure. Fig. 7 shows the relative
distribution of the level of p65 from individuals after either
stimulation using surface stimulation with antiCD3/antiCD28 mAbs or
PMA/A23187. The distribution clearly shows that normal controls always
show inducible NF-B activity that falls into a distinguishable level
from that seen for the SLE group. The SLE group showed a level that
extends from undetectable to normal. The mean level of activity in SLE
patients was statistically lower than that of the normal individuals
(p < 0.0001). RA patients exhibited levels of
NF-B induction that overlapped with those of normal individuals,
albeit in the low range. The mean level of NF-B from the RA group
was statistically lower than that of normal individuals
(p = 0.001) and statistically higher than that
of SLE patients (p = 0.01).
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B activity and clinical variables of disease activity
The group of SLE patients studied was comprised of 22 individuals
with SLE disease activity index (SLEDAI) levels that ranged from 0 to
32. Of the SLE patients, 2 had NF-B levels within 1 SD of normal, 10
had NF-B levels between 1 and 2 SD, and 10 had SD >2 SD of the
normal mean (Table I). We analyzed the
level of NF-B activity with respect to SLEDAI by regression analysis
and found that there was no correlation between SLEDAI and p65 level.
Since corticosteroids can suppress NF-B activity by increasing the
level of IB (36, 37), it was important to determine
whether steroids and/or other drugs used in the treatment of lupus were
correlated with the observed defect in NF-B binding (Table II). The abnormalities in NF-B binding
activity identified in SLE patients were seen both in individuals who
were off or on steroids (Table II). One patient on steroid showed
normal NF-B activity. In addition, in RA patients who displayed
inducible NF-B binding activity, there was no correlation between
the use of prednisone, or other disease-modifying agents (methotrexate,
hydroxychloroquin, azathioprine) and a lack of p65, as shown in
Table II.
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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B because it plays an integral role in the regulation of
IL-2. The results described here represent the first focused analysis
of the regulation of NF-B in SLE T cells.
The data presented identifies a defect in nuclear signaling in T cells
isolated from patients with SLE. We found that freshly isolated SLE T
cells showed a TCR-mediated defect in the activation of NF-B. This
defect was also present when cells were analyzed following stimulation
with PMA/A23187, which bypasses membrane-associated signaling pathways.
Abs specific for members of the NF-B family showed that the defect
is from a lack of the p65 RelA subunit. In primary T cells, we found
that the predominant NF-B subunits are p50 and p65. The levels of
p50, as analyzed by immunoblots, were similar in T cells from normal
controls, RA controls, and SLE patients, indicating that not all
NF-B/Rel components are abnormal and the defect of p65RelA accounts
for the abnormal NF-B binding activity seen in SLE T cells.
Immunoblot analyses demonstrated that the p65 subunit was undetectable
in the distinct group of patients who had undetectable NF-B binding
activity on EMSA. The absence of p65 protein was confirmed using Abs
against two distinct regions of the protein, indicating that defective
expression was not due to a loss or modification of a specific epitope.
The immunoblot analysis also excludes a sequestration of p65 in an
inactive form by the inhibitor IkB as a basis for the decreased
activity in SLE T cells. These findings suggest that patients with SLE
have abnormalities in the signaling pathway at the nuclear level.
Although altered p65 NF-B activity could reflect aberrant early
TCR-mediated signaling (4), the lack of p65 NF-B
activation following stimulation with PMA/A23187 argues for a specific
defect in NF-B regulation independent of TCR 
-chain abnormality.
Furthermore, because -deficient T cell clones are partially
competent in the induction of signal and can induce the expression of
IL-2 (38), absence of the -chain alone cannot fully
account for the defective activation of p65 in some patients.Since
primary T cells require NF-B to fully express the IL-2 gene, the
defect in NF-B in SLE patients is consistent with the previously
described defect in the expression of IL-2. In the patients examined in
this study, the abnormality of NF-B did not correlate with disease
activity. The consistent inducibility of the p65 NF-B in T cells
from RA patients, as opposed to that seen for SLE patients, suggests
that the pathologic mechanism for NF-B regulation differs between
these two autoimmune diseases.
A lack of NF-B activity, particularly the function provided by the
p65 subunit that contributes the transcriptional activating portion of
the DNA binding complex (39), provides a mechanism for a
defect in IL-2 expression. Furthermore, in the absence of p65 in lupus
T cells, the remaining p50 can form homodimers, bind DNA, and repress
gene expression (39, 40). Indeed, p50 homodimers can be
found in anergic T cells that fail to produce IL-2 (41).
Therefore, both the presence of p50 homodimers and the lack of p65 are
consistent with the reported decreased IL-2 production in SLE T
cells.
NF-B activity is present in almost all cells, and different members
of the protein family are expressed in different tissues
(42). Although many members contribute to NF-B
function, the requirement for multiple members is not clear, but one
could speculate that specificity and tissue-specific control of gene
expression is achieved through assembling unique combinations of the
different members. Genetic approaches in mice have been undertaken
where specific NF-B genes were disrupted through a knockout approach
to determine the ability of the animal to survive and develop. Although
a lack of RelA leads to embryonic death at day 16 with extensive
apoptosis in the liver (43), absence of the smaller p50
subunit is compatible with life (44).
The role of steroids in the observed decrease in NF-B binding
activity can be ruled out on the basis of two findings. First, RA
patients who were on steroids displayed normal level of NF-B
activity. Second, NF-B activity was absent in patients who were off
steroids. This finding is not surprising in light of the fact that
steroids may actually increase the amount of inactive NF-B, as IB
synthesis is increased to retain NF-B in the cytoplasm in an
inactive state to prevent nuclear translocation (37). If
steroids had a significant effect, then immunoblot analysis would
reveal either a normal level of p65 or even a greater protein level.
However, this finding was not observed.
The extent to which NF-B is altered in systemic rheumatic diseases
is unknown. In this communication, we report severely depressed NF-B
activity in SLE T cells and moderately decreased activity in T cells
from RA patients. More studies are needed to define the magnitude and
the prevalence of this abnormality in rheumatic diseases. Although
NF-B is important in the transcription of many genes that are
involved in the immune response, including IL-2, it is difficult at
present to stipulate the degree to which its deficiency is responsible
for the manifold immune aberrations that characterize lupus. Along this
line, it should be considered that the regulation of NF-B activity
is complex and involves the contribution from many family member
proteins in various cell types. Lessons learned from knockout mice may
not directly help in understanding the role of decreased NF-B
activity in the immunopathogenesis of human disease. For example, a
lack of RelB, although it does not cause embryonic lethality, is
associated with multiorgan inflammation (32). In a similar
context, IL-2-deficient mice, in contrast to what one may expect on the
basis of the in vitro function of IL-2, develop a severe multisystemic
inflammatory disease (45, 46). Apparently, the complexity
of the immune system does not permit direct extrapolation from murine
models to human disease. Therefore, further studies are needed to
investigate the function of NF-B in human systemic autoimmune
diseases and, specifically, how its defect contributes to decreased
IL-2 production.
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Acknowledgments |
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Footnotes |
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2 The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of the Army or the Department of Defense.
3 Address correspondence and reprint requests to Dr. George C. Tsokos, Department of Cellular Injury, Walter Reed Army Institute of Research, Bldg 40-3078, Washington, DC 20307. E-mail address:
4 Abbreviations used in this paper: SLE, systemic lupus erythematosus; L, ligand; RA, rheumatoid arthritis.
Received for publication March 1, 1999. Accepted for publication May 14, 1999.
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 H. Zheng, L. Ye, X. Fang, B. Li, Y. Wang, X. Xiang, L. Kong, W. Wang, Y. Zeng, L. Ye, et al. Torque Teno Virus (SANBAN Isolate) ORF2 Protein Suppresses NF-{kappa}B Pathways via Interaction with I{kappa}B Kinases J. Virol., November 1, 2007; 81(21): 11917 - 11924. [Abstract] [Full Text] [PDF]
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 J. C Crispin, V. Kyttaris, Y.-T. Juang, and G. C Tsokos Systemic lupus erythematosus: new molecular targets Ann Rheum Dis, November 1, 2007; 66(suppl_3): iii65 - iii69. [Abstract] [Full Text] [PDF]
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 K. Tenbrock, Y.-T. Juang, V. C. Kyttaris, and G. C. Tsokos Altered signal transduction in SLE T cells Rheumatology, October 1, 2007; 46(10): 1525 - 1530. [Abstract] [Full Text] [PDF]
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H. M. Gibson, C. J. Hedgcock, B. M. Aufiero, A. J. Wilson, M. S. Hafner, G. C. Tsokos, and H. K. Wong Induction of the CTLA-4 Gene in Human Lymphocytes Is Dependent on NFAT Binding the Proximal Promoter J. Immunol., September 15, 2007; 179(6): 3831 - 3840. [Abstract] [Full Text] [PDF]
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M. R. Gilbert, D. G. Carnathan, P. C. Cogswell, L. Lin, A. S. Baldwin Jr, and B. J. Vilen Dendritic Cells from Lupus-Prone Mice Are Defective in Repressing Immunoglobulin Secretion J. Immunol., April 15, 2007; 178(8): 4803 - 4810. [Abstract] [Full Text] [PDF]
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 E. Dale, M. Davis, and D. L. Faustman A role for transcription factor NF-{kappa}B in autoimmunity: possible interactions of genes, sex, and the immune response Advan Physiol Educ, December 1, 2006; 30(4): 152 - 158. [Abstract] [Full Text] [PDF]
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H. Xin, S. D'Souza, T. N. Jorgensen, A. T. Vaughan, P. Lengyel, B. L. Kotzin, and D. Choubey Increased Expression of Ifi202, an IFN-Activatable Gene, in B6.Nba2 Lupus Susceptible Mice Inhibits p53-Mediated Apoptosis J. Immunol., May 15, 2006; 176(10): 5863 - 5870. [Abstract] [Full Text] [PDF]
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 M. Torroella-Kouri, X. Ma, G. Perry, M. Ivanova, P. J. Cejas, J. L. Owen, V. Iragavarapu-Charyulu, and D. M. Lopez Diminished Expression of Transcription Factors Nuclear Factor {kappa}B and CCAAT/Enhancer Binding Protein Underlies a Novel Tumor Evasion Mechanism Affecting Macrophages of Mammary Tumor-Bearing Mice Cancer Res., November 15, 2005; 65(22): 10578 - 10584. [Abstract] [Full Text] [PDF]
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D. Tao, L. Shangwu, W. Qun, L. Yan, J. Wei, L. Junyan, G. Feili, J. Boquan, and T. Jinquan CD226 Expression Deficiency Causes High Sensitivity to Apoptosis in NK T Cells from Patients with Systemic Lupus Erythematosus J. Immunol., February 1, 2005; 174(3): 1281 - 1290. [Abstract] [Full Text] [PDF]
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V. C. Kyttaris, Y.-T. Juang, K. Tenbrock, A. Weinstein, and G. C. Tsokos Cyclic Adenosine 5'-Monophosphate Response Element Modulator Is Responsible for the Decreased Expression of c-fos and Activator Protein-1 Binding in T Cells from Patients with Systemic Lupus Erythematosus J. Immunol., September 1, 2004; 173(5): 3557 - 3563. [Abstract] [Full Text] [PDF]
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 V C Kyttaris, Y-T Juang, and G C Tsokos Gene therapy in systemic lupus erythematosus Lupus, May 1, 2004; 13(5): 353 - 358. [Abstract] [PDF]
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 T. Hayashi and D. L. Faustman Role of Defective Apoptosis in Type 1 Diabetes and Other Autoimmune Diseases Recent Prog. Horm. Res., January 1, 2003; 58(1): 131 - 153. [Abstract] [Full Text] [PDF]
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Y.-T. Juang, K. Tenbrock, M. P. Nambiar, M. F. Gourley, and G. C. Tsokos Defective Production of Functional 98-kDa Form of Elf-1 Is Responsible for the Decreased Expression of TCR {zeta}-Chain in Patients with Systemic Lupus Erythematosus J. Immunol., November 15, 2002; 169(10): 6048 - 6055. [Abstract] [Full Text] [PDF]
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K. Tenbrock, Y.-T. Juang, M. F. Gourley, M. P. Nambiar, and G. C. Tsokos Antisense Cyclic Adenosine 5'-Monophosphate Response Element Modulator Up-Regulates IL-2 in T Cells from Patients with Systemic Lupus Erythematosus J. Immunol., October 15, 2002; 169(8): 4147 - 4152. [Abstract] [Full Text] [PDF]
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R. Valero, M.-L. Baron, S. Guerin, S. Beliard, H. Lelouard, B. Kahn-Perles, B. Vialettes, C. Nguyen, J. Imbert, and P. Naquet A Defective NF-{kappa}B/RelB Pathway in Autoimmune-Prone New Zealand Black Mice Is Associated with Inefficient Expansion of Thymocyte and Dendritic Cells J. Immunol., July 1, 2002; 169(1): 185 - 192. [Abstract] [Full Text] [PDF]
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J. Liu and D. Beller Aberrant Production of IL-12 by Macrophages from Several Autoimmune-Prone Mouse Strains Is Characterized by Intrinsic and Unique Patterns of NF-{kappa}B Expression and Binding to the IL-12 p40 Promoter J. Immunol., July 1, 2002; 169(1): 581 - 586. [Abstract] [Full Text] [PDF]
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R Hooghe, Z Dogusan, N Martens, B Velkeniers, and E L Hooghe-Peters Effects of prolactin on signal transduction and gene expression: possible relevance for systemic lupus erythematosus Lupus, October 1, 2001; 10(10): 719 - 727. [Abstract] [PDF]
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 D. SAHALI, A. PAWLAK, S. L. GOUVELLO, P. LANG, A. VALANCIUTE, P. REMY, C. LOIRAT, P. NIAUDET, A. BENSMAN, and G. GUELLAEN Transcriptional and Post-Transcriptional Alterations of I {kappa}B{alpha} in Active Minimal-Change Nephrotic Syndrome J. Am. Soc. Nephrol., August 1, 2001; 12(8): 1648 - 1658. [Abstract] [Full Text] [PDF]
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D A Horwitz Peripheral blood CD4/ T cells in systemic lupus erythematosus Lupus, May 1, 2001; 10(5): 319 - 320. [PDF]
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T. M. Herndon, X. C. Shan, G. C. Tsokos, and R. L. Wange ZAP-70 and SLP-76 Regulate Protein Kinase C-{{theta}} and NF-{{kappa}}B Activation in Response to Engagement of CD3 and CD28 J. Immunol., May 1, 2001; 166(9): 5654 - 5664. [Abstract] [Full Text] [PDF]
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S Sipka, K Szucs, S Szanto, I Kovacs, G Lakos, E Kiss, P Antal-Szalmas, G Szegedi, and P Gergely Glucocorticosteroid dependent decrease in the activity of calcineurin in the peripheral blood mononuclear cells of patients with systemic lupus erythematosus Ann Rheum Dis, April 1, 2001; 60(4): 380 - 384. [Abstract] [Full Text] [PDF]
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E. E. Solomou, Y.-T. Juang, M. F. Gourley, G. M. Kammer, and G. C. Tsokos Molecular Basis of Deficient IL-2 Production in T Cells from Patients with Systemic Lupus Erythematosus J. Immunol., March 15, 2001; 166(6): 4216 - 4222. [Abstract] [Full Text] [PDF]
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