1: Immunology. 2005 Mar;114(3):313-21. 

Interleukin-10 (IL-10) mediated suppression of IL-12 production in RAW 264.7
cells also involves c-rel transcription factor.

Rahim SS, Khan N, Boddupalli CS, Hasnain SE, Mukhopadhyay S.

Centre for DNA Fingerprinting and Diagnostics (CDFD), Nacharam, Hyderabad,
India.

Interleukin-10 (IL-10) is known to inhibit IL-12 production in macrophages
primarily at the transcriptional level with the involvement of p50 and p65
nuclear factor-kappaB (NF-kappaB). We demonstrate that the c-rel transcription
factor also plays a major role in IL-10-mediated IL-12 suppression. Treatment of
macrophages with recombinant IL-10 inhibited nuclear c-rel levels, whereas
addition of neutralizing anti-IL-10 antibody up-regulated both nuclear c-rel
levels and IL-12 production by macrophages. Decreased nuclear c-rel was
associated with a reduction in phosphorylation of inhibitory kappa B alpha
(IkappaBalpha) in the cytoplasm, indicating that IL-10 prevents degradation of
IkappaBalpha and the subsequent translocation of c-rel into the nucleus.
Treatment with leptomycin B, a known inhibitor of c-rel at a concentration of 10
nm, when used with anti-IL-10 antibody, resulted in reduced expression of IL-12.
In a complementary experiment, in vitro transient expression of p65 NF-kappaB
could not rescue the inhibitory effect of IL-10 on IL-12 production, suggesting
that NF-kappaB alone was not sufficient to restore IL-12 production during IL-10
treatment. However, over-expression of c-rel resulted in IL-12 restoration upon
stimulation with lipopolysaccharide plus interferon-gamma during IL-10
treatment. Our studies highlight the involvement of c-rel in IL-10-mediated
IL-12 regulation.

PMID: 15720433 [PubMed - indexed for MEDLINE]


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2: J Immunol. 2004 Oct 1;173(7):4479-91. 

CpG DNA induces IgG class switch DNA recombination by activating human B cells
through an innate pathway that requires TLR9 and cooperates with IL-10.

He B, Qiao X, Cerutti A.

Department of Pathology, Weill Medical College, Cornell University, New York, NY
10021, USA.

TLRs are pattern recognition receptors that initiate innate immune responses.
TLR9 detects microbial DNA with hypomethylated CpG motifs and in humans is
preferentially expressed by IFN-alpha-producing plasmacytoid dendritic cells and
B cells. In addition to favoring IFN-alpha release, TLR9 signals B cell
activation, proliferation, and IgM production. Recent findings suggest that CpG
DNA-TLR9 interaction plays a key role in systemic lupus erythematosus and
rheumatoid arthritis, two autoimmune disorders characterized by dysregulated
production of DNA-reactive IgG. We show that CpG DNA initiates germline
C(gamma)1, C(gamma)2, and C(gamma)3 gene transcription by activating B cells
through a TLR9-mediated NF-kappaB-Rel-dependent innate pathway that cooperates
with IL-10 through STAT proteins and IFN-responsive factors. This pathway is
inhibited by chloroquine, a drug that attenuates the clinical manifestations of
IgG-mediated autoimmune disorders. Germline C(gamma) gene transcription is
associated with up-regulation of activation-induced cytidine deaminase, a key
element of the B cell class switch-inducing machinery, and is followed by class
switch DNA recombination from C(micro) to C(gamma)1, C(gamma)2, and C(gamma)3.
Subsequent IgG production requires additional signals from BCR and a B
cell-activating factor of the TNF family (BAFF), produced by dendritic cells
upon exposure to IFN-alpha. Our findings suggest that CpG DNA-TLR9 interaction
may be important to initiate or amplify early T cell-independent IgG responses
against pathogens. This implies that CpG DNA released during infections may
exacerbate autoimmunity by stimulating autoreactive B cells to switch from an
IgM to a more pathogenic IgG isotype.

PMID: 15383579 [PubMed - indexed for MEDLINE]


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3: Blood. 2005 Jan 15;105(2):689-96. Epub 2004 Jul 13. 

STAT3 regulates NF-kappaB recruitment to the IL-12p40 promoter in dendritic
cells.

Hoentjen F, Sartor RB, Ozaki M, Jobin C.

Center for Gastrointestinal Biology and Diseases, University of North Carolina
at Chapel Hill, USA.

Interleukin-10-deficient (IL-10(-/-)) mice develop an IL-12-mediated intestinal
inflammation in the absence of endogenous IL-10. The molecular mechanisms of the
dysregulated IL-12 responses in IL-10(-/-) mice are poorly understood. In this
study, we investigated the role of nuclear factor-kappa B (NF-kappaB) and signal
transducers and activators of transcription 3 (STAT3) in lipopolysaccharide
(LPS)-induced IL-12p40 gene expression in bone marrow derived-dendritic cells
(BMDCs) isolated from wild-type (WT) and IL-10(-/-) mice. We report higher
IL-12p40 mRNA accumulation and protein secretion in LPS-stimulated BMDCs
isolated from IL-10(-/-) compared with WT mice. LPS-induced NF-kappaB signaling
is similar in IL-10(-/-) and WT BMDCs as measured by IkappaBalpha
phosphorylation and degradation, RelA phosphorylation and nuclear translocation,
and NF-kappaB transcriptional activity, with no down-regulatory effects of
exogenous IL-10. Chromatin immunoprecipitation demonstrated enhanced NF-kappaB
(cRel, RelA) binding to the IL-12p40 promoter in IL-10(-/-) but not WT BMDCs.
Interestingly, LPS induced STAT3 phosphorylation in WT but not IL-10(-/-) BMDCs,
a process blocked by IL-10 receptor blocking antibody. Adenoviral gene delivery
of a constitutively active STAT3 but not control green fluorescence protein
(GFP) virus blocked LPS-induced IL-12p40 gene expression and cRel recruitment to
the IL-12p40 promoter. In conclusion, dysregulated LPS-induced IL-12p40 gene
expression in IL-10(-/-) mice is due to enhanced NF-kappaB recruitment to the
IL-12p40 promoter in the absence of activated STAT3.

PMID: 15251981 [PubMed - indexed for MEDLINE]


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4: Mol Cancer Res. 2003 Jul;1(9):631-42. 

Erratum in:
    Mol Cancer Res. 2003 Aug;1(10):788.

Interleukin-10 activation of the interleukin-10E1 pathway and tissue inhibitor
of metalloproteinase-1 expression is enhanced by proteasome inhibitors in
primary prostate tumor lines.

Stearns ME, Wang M, Hu Y, Garcia FU.

Department of Pathology and Laboratory Medicine, College of Medicine, Drexel
University, Philadelphia, PA 19102-1192, USA. stearnsm1@aol.com

The interleukin-10 (IL-10) activation of Janus kinase (JAK) family members
(JAK1/TYK2) and IL-10E1 is subsequently inactivated by approximately 3-4 h in
primary prostate tumor lines. We examined the effect of proteasome inhibition on
IL-10 activation of the IL-10E1 pathway following stimulation of HPCA-10a cells.
Treatment of HPCA-10a cells with the proteasome inhibitor,
N-acetyl-L-leucinyl-L-leucinyl-norleucinal (LLnL), led to stable tyrosine
phosphorylation of the IL-10 receptor and IL-10E1 following stimulation. Further
investigation showed that these stable phosphorylation events were the result of
prolonged activation of JAK1 and TYK2 plus IL-10E1. IL-10E1 signaling normally
induced the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and
LLnL treatment of the HPCA-10a and HPCA-10c cells significantly enhanced IL-10
induction of TIMP-1 levels to block tumor cell invasion in modified Boyden
chamber invasion assays. These observations were confirmed using pharmacologic
inhibitors by Western blot and ELISAs. In the presence of LLnL, stable
phosphorylation of IL-10E1 and induction of TIMP-1 was abrogated if the tyrosine
kinase inhibitor, staurosporine, was added. The effect of staurosporine on
IL-10E1 phosphorylation and TIMP-1 could be overcome if the phosphatase
inhibitor, vanadate, was also added, suggesting that phosphorylated IL-10E1
could be stabilized by phosphatase, but not by proteasome inhibition. These
observations are consistent with the hypothesis that proteasome-mediated protein
degradation can modulate the activity of the IL-10E1 pathway and TIMP-1
induction by regulating the deactivation of JAK1/TYK2.

PMID: 12861049 [PubMed - indexed for MEDLINE]


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5: Ann Surg. 2003 Jul;238(1):49-58. 

IL-10 increases tissue injury after selective intestinal ischemia/reperfusion.

Nussler NC, Muller AR, Weidenbach H, Vergopoulos A, Platz KP, Volk HD, Neuhaus
P, Nussler AK.

Department of Surgery, Charite, Campus Virchow-Klinikum, Humboldt University of
Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
natascha.nuessler@charite.de

OBJECTIVE This study focused on the effect of immunoregulatory cytokines on
tissue injury after intestinal ischemia/reperfusion (IR). Furthermore, the role
of nitric oxide, heme oxygenase-1 (HO-1) and the transcription factor
NF-kappaB/Rel in the disease process was evaluated.SUMMARY BACKGROUND DATA
Oxidative stress and inflammatory gene products contribute to
ischemia/reperfusion injury (IRI). However, expression of stress proteins such
as the inducible nitric oxide synthase (NOS-2) and HO-1 might also provide
protection against IRI.METHODS IR was achieved in Lewis rats by selective
clamping of the superior mesenteric artery. IL-2 or IL-10 was administered
intravenously before reperfusion. Animals were killed 1 hour, 4 hours, and 24
hours after reperfusion. Tissue destruction was assessed by hyaluronic acid (HA)
and aminoaspartate-transaminase (AST) serum levels, whereas reduction of
glutathione (GSH) tissue levels was used as a marker for oxidative stress.
Furthermore, the activation of NF-kappaB/Rel and the expression of NOS-2 and
HO-1 were analyzed.RESULTS IR resulted in tissue destruction and significantly
reduced GSH tissue levels in the intestines and liver. In addition,
NF-kappaB/Rel activation and increased NOS-2 and HO-1 mRNA expression were
detected in both organs after IR. IL-2 administration resulted in clinical
improvement of the animals and was associated with increased NF-kappaB/Rel
activation and enhanced NOS-2 and HO-1 mRNA expression. In contrast, IL-10
resulted in increased tissue destruction in both organs and sustained reduction
of GSH levels in the intestines. Furthermore, IL-10 administration failed to
enhance NF-kappaB/Rel activity, NOS-2 mRNA, or HO-1 mRNA expression after
IR.CONCLUSION IL-10 resulted in increased tissue damage after intestinal IR.
This detrimental effect of IL-10 might have been the result of reduced NOS-2 and
HO-1 mRNA expression. In contrast, the beneficial effect of IL-2 might have
relied on increased HO-1 expression and NOS-2 activity. These controversial
effects of IL-2 and IL-10 might have been mediated through transcriptional
regulation of NOS-2 and HO-1 gene expression.

Publication Types:
    Evaluation Studies

PMID: 12832965 [PubMed - indexed for MEDLINE]


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6: J Immunol. 2003 Apr 15;170(8):3963-70. 

Cross-linking of CD32 induces maturation of human monocyte-derived dendritic
cells via NF-kappa B signaling pathway.

Banki Z, Kacani L, Mullauer B, Wilflingseder D, Obermoser G, Niederegger H,
Schennach H, Sprinzl GM, Sepp N, Erdei A, Dierich MP, Stoiber H.

Institute of Hygiene and Social Medicine, Leopold-Franzens University and Ludwig
Boltzmann Institute for AIDS Research, Innsbruck, Austria.

Dendritic cells (DC) represent a unique set of APCs that initiate immune
responses through priming of naive T cells. Maturation of DC is a crucial step
during Ag presentation and can be induced by triggering a broad spectrum of DC
surface receptors. Although human DC express several receptors for the Fc
portion of IgG which were described to play an important role in Ag
internalization, little is known about the effects of IgG or immune complexes on
DC maturation. In this study, we show that cross-linking of FcgammaR-type II
(CD32) with immobilized IgG (imIgG) can induce maturation of human
monocyte-derived DC via the NF-kappaB signaling pathway. IgG-mediated maturation
was accompanied by a moderate increase of IL-10 secretion, whereas no IL-12
production was observed. Involvement of CD32 was further supported by
experiments with the anti-CD32 mAb, which blocked IgG-triggered DC maturation
and cytokine secretion significantly. Furthermore, DC cultivated in the presence
of imIgG induced allogeneic T cell proliferation. Because this imIgG-induced
maturation was considerably impaired in monocyte-derived DC from systemic lupus
erythematosus patients, we suggest that DC, which matured in the presence of
immune complexes, may contribute to prevention of pathological immune responses.

PMID: 12682223 [PubMed - indexed for MEDLINE]


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7: Pediatr Res. 2003 Jul;54(1):105-12. Epub 2003 Apr 2. 

BCG promotes cord blood monocyte-derived dendritic cell maturation with nuclear
Rel-B up-regulation and cytosolic I kappa B alpha and beta degradation.

Liu E, Law HK, Lau YL.

Department of Pediatrics, Faculty of Medicine, The University of Hong Kong,
Queen Mary Hospital, Pokfulam, Hong Kong, China. lauylung@hkucc.hku.hk

Mycobacterium bovis bacillus Calmette-Guerin (BCG) is given to millions of
neonates in developing countries as a vaccine against Mycobacterium
tuberculosis; however, little is known about the initiation of response in
neonatal dendritic cells (DCs) to BCG. To address this issue, the interaction of
BCG with human cord blood monocyte-derived DCs was studied. We showed that BCG
could promote cord blood monocyte-derived DC maturation by up-regulation of
CD80, CD83, CD86, CD40, and MHC class II molecules and down-regulation of
mannose receptor. BCG was able to induce similar levels of tumor necrosis
factor-alpha and IL-10 but no bioactive IL-12p70 production from cord blood DCs
as from adult blood DCs. Functionally BCG-treated cord blood DCs had higher
ability to induce mixed lymphocyte reaction than non-BCG-treated cord blood DCs.
Both non-BCG-treated and BCG-treated cord blood DCs efficiently induced a high
level of IL-10, medium level of interferon-gamma, but little IL-4 production by
cord blood naive CD4+ T cells. Heat shock protein 65, a key component of BCG,
had no effect on cord blood DC maturation in terms of CD86, MHC class II, and
mannose receptor up-regulation. During the BCG-induced maturation process of
cord blood DCs, nuclear transcription factor Rel-B was up-regulated and
cytosolic Rel-B down-regulated with cytosolic IkappaB alpha and beta
degradation. These results suggest that BCG can promote cord blood
monocyte-derived DC maturation, and that the mechanism is through the
up-regulation of nuclear Rel-B secondary to the degradation of cytosolic IkappaB
alpha and beta.

PMID: 12672905 [PubMed - indexed for MEDLINE]


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8: J Immunol. 2002 Jun 1;168(11):5491-8. 

CD40 ligation conditions dendritic cell antigen-presenting function through
sustained activation of NF-kappaB.

O'Sullivan BJ, Thomas R.

Center for Immunology and Cancer Research, University of Queensland, Princess
Alexandra Hospital, Brisbane, Queensland, Australia.

An understanding of the biochemical control of dendritic cell (DC)
differentiation/activation is essential for improving T cell immunity by various
immunotherapeutic approaches, including DC immunization. Ligation of CD40
enhances DC function, including conditioning for CTL priming. NF-kappaB, and
particularly RelB, is an essential control pathway for myeloid DC
differentiation. Furthermore, RelB regulates B cell Ag-presenting function. We
hypothesized that CD40 ligand (CD40L) and TNF-alpha, which differ in their
capacity to condition DC, would also differ in their capacity to activate
NF-kappaB. DC differentiated for 2 days from monocytes in the presence of GM-CSF
and IL-4 were used as a model, as NF-kappaB activity was constitutively low. The
capacity of DC to activate T cells following CD40L treatment was enhanced
compared with TNF-alpha treatment, and this was NF-kappaB dependent. Whereas
RelB/p50 translocation induced by TNF-alpha was attenuated after 6 h, RelB/p50
nuclear translocation induced by CD40L was sustained for at least 24 h. The
mechanism of this difference related to enhanced degradation of IkappaBalpha
following CD40L stimulation. However, NF-kappaB activation induced by TNF-alpha
could be sustained by blocking autocrine IL-10. These data indicate that
NF-kappaB activation is essential for T cell activation by DC, and that this
function is enhanced if DC NF-kappaB activation is prolonged. Because IL-10
moderates DC NF-kappaB activation by TNF-alpha, sustained NF-kappaB activation
can be achieved by blocking IL-10 in the presence of stimuli that induce
TNF-alpha.

PMID: 12023343 [PubMed - indexed for MEDLINE]


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9: Br J Pharmacol. 2001 May;133(1):49-60. 

The biphasic immunoregulation of pyrimidylpiperazine (Y-40138) is IL-10
sensitive and requires NF-kappa B targeting in the alveolar epithelium.

Haddad JJ, Safieh-Garabedian B, Saade NE, Land SC.

Oxygen Signalling Group, Centre for Research into Human Development, Tayside
Institute of Child Health, Faculty of Medicine, Ninewells Hospital and Medical
School, University of Dundee, Dundee, DD1 9SY. j.j.haddad@dundee.ac.uk

1. Pyrimidylpiperazine (Y-40138), a synthetic derivative of
N-[1-(4-([4-(pyrimidin-2-yl)piperazin-1-yl]methyl)phenyl)cyclopropyl] acetamide,
is a novel dual regulator of pro- and anti-inflammatory cytokines in vivo. The
aim of the present study was to determine the signal transduction mechanisms
implicated in vitro. 2. In alveolar epithelial cells, pre-treatment (30 min)
with Y-40138 reduced LPS-induced biosynthesis of IL-1 beta, IL-6 and TNF-alpha,
an effect paralleled by up-regulating an anti-inflammatory counter-loop mediated
through IL-10. 3. This differential regulation of pro- and anti-inflammatory
signals was accompanied by an inhibition of the nuclear localization of
selective NF-kappa B subunits, particularly NF-kappa B(1) (p50), RelA (p65), the
major transactivating member of the Rel family, RelB (p68) and c-Rel (p75). In
addition, Y-40138 blockaded, in a dose-dependent manner, the LPS-induced nuclear
activation of NF-kappa B. 4. Analysis of the upstream pathway involved in
Y-40138-dependent retardation of LPS-induced NF-kappa B translocation/activation
revealed the involvement of an I kappa B-alpha sensitive pathway. Pre-treatment
with Y-40138 ameliorated LPS-induced degradation of I kappa B-alpha in the
cytosolic compartment and retarded its phosphorylation, suggesting the
involvement of an upstream kinase. 5. Recombinant IL-10 (0 -- 10 ng ml(-1))
blockaded, in a dose-dependent manner, LPS-induced biosynthesis of IL-1 beta,
IL-6 and TNF-alpha. Furthermore, rhIL-10 reduced the DNA binding activity of
NF-kappa B. Immunoneutralization of endogenous IL-10 by a polyclonal alpha IL-10
(5 microg ml(-1)) reversed the inhibitory effect of Y-40138 on pro-inflammatory
cytokines and partially restored the DNA binding activity of NF-kappa B. 6.
These results indicate that Y-40138 mediated dual immunoregulation of pro- and
anti-inflammatory cytokines is IL-10 sensitive and mediated through the I kappa
B-alpha/NF-kappa B signal transduction pathway.

PMID: 11325794 [PubMed - indexed for MEDLINE]


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10: J Immunol. 2000 Feb 15;164(4):1940-51. 

A prominent role for Sp1 during lipopolysaccharide-mediated induction of the
IL-10 promoter in macrophages.

Brightbill HD, Plevy SE, Modlin RL, Smale ST.

Department of Microbiology, Division of Dermatology, University of California,
Los Angeles, School of Medicine, Los Angeles, CA 90095, USA.

IL-10 is an antiinflammatory cytokine secreted by activated macrophages and Th2
cells. IL-10 secretion promotes the down-regulation of proinflammatory cytokine
synthesis and the development of Th2 responses. In macrophages, proinflammatory
cytokines appear to be induced by similar mechanisms, but the IL-10 induction
mechanisms have not been examined. We have analyzed the murine IL-10 promoter in
the RAW264.7 macrophage line activated with LPS. A comprehensive mutant analysis
revealed only one element upstream of the core promoter that was essential for
promoter induction. A refined mutant analysis localized this element to
nucleotides -89 to -78, and gel shift experiments revealed that it represents a
nonconsensus binding site for Sp1. The functional relevance of Sp1 was supported
by the high affinity of the interaction, the close correlation between the
nucleotides required for Sp1 binding and promoter function, and the ability of
an Sp1 consensus sequence to substitute for the -89/-78 promoter sequence.
Evidence that Sp1 may be a target of signaling pathways involved in IL-10
induction was provided by the exclusive requirement for the Sp1 binding site, by
the ability of the Sp1 site to confer induction to a heterologous promoter, and
by the delineation of an Sp1 domain that can mediate induction. No relevant
contribution from Rel, C/EBP (CCAAT/enhancer-binding protein), or AP-1 binding
sites, which regulate most proinflammatory cytokine promoters, was observed.
Together, these results demonstrate that IL-10 gene regulation is distinct from
the regulation of proinflammatory cytokine genes, and suggest that Sp1 may be a
central mediator of IL-10 induction.

PMID: 10657644 [PubMed - indexed for MEDLINE]


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11: J Immunol. 2000 Feb 15;164(4):1722-9. 

Inhibition of IL-12 production in human monocyte-derived macrophages by TNF.

Ma X, Sun J, Papasavvas E, Riemann H, Robertson S, Marshall J, Bailer RT, Moore
A, Donnelly RP, Trinchieri G, Montaner LJ.

The Wistar Institute, Philadelphia, PA 19104, USA.

IL-12 is a pivotal cytokine that links the innate and adaptive immune responses.
TNF-alpha also plays a key role in orchestrating inflammation and immunity. The
reciprocal influence of these two inflammatory mediators on each other may have
significant impact on the cytokine balance that shapes the type and extent of
immune responses. To investigate the relationship between TNF-alpha and IL-12
production, we analyzed the effects of exposure of human monocyte-derived
macrophages to TNF-alpha on LPS- or Staphylococcus aureus-induced IL-12
production in the presence or absence of IFN-gamma. TNF-alpha is a potent
inhibitor of IL-12 p40 and p70 secretion from human macrophages induced by LPS
or S. aureus. IL-10 is not responsible for the TNF-alpha-mediated inhibition of
IL-12. TNF-alpha selectively inhibits IL-12 p40 steady-state mRNA, but not those
of IL-12 p35, IL-1alpha, IL-1beta, or IL-6. Nuclear run-on analysis identified
this specific inhibitory effect at the transcriptional level for IL-12 p40
without down-regulation of the IL-12 p35 gene. The major transcriptional factors
identified to be involved in the regulation of IL-12 p40 gene expression by LPS
and IFN-gamma, i.e., c-Rel, NF-kappaB p50 and p65, IFN regulatory factor-1, and
ets-2, were not affected by TNF-alpha when examined by nuclear translocation and
DNA binding. These data demonstrate a selective negative regulation on IL-12 by
TNF-alpha, identifying a direct negative feedback mechanism for
inflammation-induced suppression of IL-12 gene expression.

PMID: 10657616 [PubMed - indexed for MEDLINE]


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12: J Immunol. 1999 Jun 1;162(11):6442-50. 

In vivo inhibition of NF-kappa B in T-lineage cells leads to a dramatic decrease
in cell proliferation and cytokine production and to increased cell apoptosis in
response to mitogenic stimuli, but not to abnormal thymopoiesis.

Ferreira V, Sidenius N, Tarantino N, Hubert P, Chatenoud L, Blasi F, Korner M.

Laboratoire d'Immunologie Cellulaire et Tissulaire, Centre National de la
Recherche Scientifique UMR 7627, Hopital de la Pitie-Salpetriere, Paris, France.

To understand the role of NF-kappa B complexes in T cell development and
activation, we have generated transgenic mice in which RelA and c-Rel complexes
were selectively inhibited in the T-lineage cells by specific expression of a
trans-dominant form of I kappa B alpha. Transgene expression did not affect the
thymic development, but led to lowered numbers of splenic T cells and to a
dramatic decrease in the ex vivo proliferative response of splenic T
lymphocytes. Analysis of IL-2 and IL-2R alpha expression demonstrated that the
perturbation of the proliferation response was not attributable to an abnormal
expression of these genes. In contrast, expression of IL-4, IL-10, and IFN-gamma
was strongly inhibited in the transgenic T cells. The proliferative deficiency
of the transgenic T cells was associated with an increased apoptosis. These
results point out the involvement of NF-kappa B/Rel family proteins in growth
signaling pathways by either regulating proteins involved in the IL-2 signaling
or by functionally interfering with the cell cycle progression.

PMID: 10352258 [PubMed - indexed for MEDLINE]


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13: Eur J Haematol. 1997 Sep;59(3):162-70. 

Activation of the interleukin-10 gene in the human T lymphoma line HuT 78:
identification and characterization of NF-kappa B binding sites in the
regulatory region of the interleukin-10 gene.

Mori N, Prager D.

Division of Hematology/Oncology, UCLA School of Medicine, USA.
n-mori@net.nagasaki-u.ac.jp

Interleukin-10 (IL-10) is a pleiotropic cytokine which has potent inhibitory
effects on macrophages and T cells, and contributes to the regulation of
proliferation and differentiation of B cells. Resting HuT 78, a T-cell line
derived from a Sezary lymphoma, produced significant amounts of IL-10 compared
with another T-cell line, Jurkat. To elucidate the mechanisms by which the IL-10
is expressed, we have analyzed their activity in human T-cell lines. We report
here evidence that members of the family of transcription factors nuclear
factor-kappa B (NF-kappa B)/Rel can specifically recognize 3 identical sequences
located in the 5'-regulatory region of IL-10 gene in resting HuT 78 cells,
whereas Jurkat cells expressed high levels of NF-kappa B consisting of p65 and
p50 only upon activation with tumor necrosis factor-alpha (TNF-alpha). In HuT 78
cells, p50 was the major component in the NF-kappa B complexes. Exogenous
TNF-alpha and the monoclonal antibody to TNF-alpha did not affect IL-10
production and constitutive NF-kappa B binding levels in HuT 78 cells. This
study is the first demonstration of a role for NF-kappa B in the IL-10 gene
expression, and suggests that its expression does not require TNF-alpha. These
novel findings may account for the specific IL-10 gene expression in T cells.

PMID: 9310124 [PubMed - indexed for MEDLINE]


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14: J Immunol. 1996 Mar 15;156(6):2119-23. 

IL-10 inhibits nuclear factor-kappa B/Rel nuclear activity in CD3-stimulated
human peripheral T lymphocytes.

Romano MF, Lamberti A, Petrella A, Bisogni R, Tassone PF, Formisano S, Venuta S,
Turco MC.

Department of Biochemistry, Federico II University, Napoli, Italy.

IL-10 markedly reduces nuclear factor (NF)-kappa B/Rel nuclear activity induced
in PBMC by stimulation with the anti-CD3 mAb OKT3. The inhibition is exerted
specifically on the NF-kappa B/Rel activation induced by mAb OKT3, and not that
produced by PMA. As judged by supershifting the DNA-protein complexes with Abs
recognizing specific components of the NF-kappa B/Rel protein family, the
p50/p65 (Rel A) heterodimeric form of NF-kappa B is primarily affected. The
maximal effect is observed at the IL-10 concentration of 20 U/ml. IL-10
inhibitory activity is exerted on T lymphocytes and is mediated by monocytes.
Indeed, monocytes pretreated with IL-10 are able so inhibit NF-kappa B nuclear
activity in purified T lymphocytes stimulated with OKT3. Soluble factors do not
appear to be involved in the mechanism of inhibition. On the other hand, the
up-regulation of CD80 Ag, found on monocytes obtained from PBMC incubated with
OKT3, is not detected after addition of IL-10, and the anti-CD28 mAb CLB-CD28/1
restores the NF-kappa B/Rel nuclear activity in IL-10-inhibited lymphocytes.
Therefore, the NF-kappa B/Rel inhibition might be ascribed to a lack of
cooperation between accessory cells and T lymphocytes, resulting from
down-regulation of a costimulatory molecule, such as CD80, produced by IL-10 on
activated monocytes. Our results demonstrate that IL-10 can inhibit the
induction of NF-kappa B/Rel nuclear activity in CD3-stimulated T lymphocytes.
Since inappropriate activation of kappa B-driven genes has a physiopathologic
role in a number of diseases, such as HIV infection, our findings support the
possibility of using this cytokine to suppress an undesirable activation of
these transcription factors.

PMID: 8690900 [PubMed - indexed for MEDLINE]


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