1 First Department of Medicine, 3 Department of Pathology, 2 First Department of Medicine Pathophysiology Section, and 4 Department of Virology, Johannes Gutenberg-University, 55101 Mainz; and 5 Department of Pathology, University of Cologne, 50931 Cologne, Germany
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
In autoimmune hepatitis,
strong TGF-1 expression is found in the inflamed liver. TGF-
overexpression may be part of a regulatory immune response attempting
to suppress autoreactive T cells. To test this hypothesis, we
determined whether impairment of TGF-
signaling in T cells leads to
increased susceptibility to experimental autoimmune hepatitis (EAH).
Transgenic mice of strain FVB/N were generated expressing a
dominant-negative TGF-
type II receptor in T cells under the control
of the human CD2 promoter/locus control region. On induction of EAH,
transgenic mice showed markedly increased portal and periportal
leukocytic infiltrations with hepatocellular necroses compared with
wild-type mice (median histological score = 1.8 ± 0.26 vs.
0.75 ± 0.09 in wild-type mice; P < 0.01).
Increased IFN-
production (118 vs. 45 ng/ml) and less IL-4
production (341 vs. 1,256 pg/ml) by mononuclear cells isolated from
transgenic livers was seen. Impairment of TGF-
signaling in T cells
therefore leads to increased susceptibility to EAH in mice. This
suggests an important role for TGF-
in immune homeostasis in the
liver and may teleologically explain TGF-
upregulation in response to T cell-mediated liver injury.
transgenic mice; dominant-negative transforming growth factor-
type II receptor
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
AUTOIMMUNE
HEPATITIS (AIH) is thought to be a T cell-mediated disease
(28). Little is known about the factors influencing susceptibility to AIH (11). If left untreated, the disease
may rapidly lead to liver fibrosis, and cirrhosis quite often is the first presentation of a patient with AIH (10). The
fibrogenic potential of TGF-1 is well known and has been shown in
experimental models overexpressing TGF-
1 in the liver (5,
24). In patients with AIH, strong TGF-
1 expression in the
liver has been detected, which seems to correlate with disease activity
(4).
In addition to its fibrogenic and mitoinhibitory potential, TGF-1 is
a key regulator of immune homeostasis (34). TGF-
1 knockout mice show a multifocal inflammatory disorder and die within 4 wk of birth (29, 49). Crossing TGF-
1 knockout mice with
SCID mice results in mice with no inflammatory lesions, suggesting a
role for lymphocytes in the observed immune dysregulation
(13). However, because of its multiple effects on
different cell types, it has been difficult to delineate the actions of
TGF-
as specific to T cells in the knockout model. In vitro studies
have shown that TGF-
1 exerts profound and partly contradictory
regulatory effects on T cells that depend on the context of its
production (34). Inhibitory effects on proliferation, IL-2
production, and various effector functions such as cytokine production
and signaling (1, 15, 16, 18, 21, 25) as well as cytolytic activity (42, 48) have been described.
All three isoforms of TGF- (TGF-
1, 2, and 3) bind to a single
receptor consisting of two subunits and mediate their highly pleiotropic effects depending on their expression pattern and microenvironment (41). On binding of the ligand to the
TGF-
type II receptor, the type I receptor associates with this
complex and is subsequently phosphorylated by the intracellular
serine-threonine kinase domain of the type II receptor (2, 3,
14). The TGF-
type I receptor then phosphorylates and
activates Smad proteins, which mediate expression of TGF-
response
genes (54, 12). The mutated dominant-negative TGF-
type
II receptor (
kT
RII) lacks the intracellular kinase domain. It
titrates the type I receptor into inactive complexes, resulting in the
inhibition of the signaling cascade (7).
In AIH, TGF- might be produced to suppress autoreactive T cells
invading the liver. This local immunoregulatory response may help to
prevent fulminant exacerbations of AIH and enable induction of
spontaneous remissions (37), but at the same time it may
promote fibrosis. To test this hypothesis of an important immunoregulatory role of TGF-
in AIH, we generated transgenic mice
overexpressing a dominant-negative TGF-
type II receptor in T cells,
thereby overcoming the restrictions of the TGF-
1 knockout model. The
truncated receptor was expressed under the control of the human CD2
promoter/enhancer, which is expressed in a copy-dependent manner in T
cells (56). The hCD2-
kT
RII transgenic mice were
characterized and subsequently used to study the possible effects of
TGF-
on T cells in the induction of experimental autoimmune
hepatitis (EAH), an animal model for AIH. EAH shares several features
with AIH and is induced by immunizing mice with syngenic liver
homogenate in adjuvant. The disease is most likely T cell mediated
because lymphocytic infiltrates and T cell reactivity to liver antigens
can be demonstrated (27, 38, 52) and the disease can
adoptively be transferred by using activated splenocytes (38,
44).
The hCD2-kT
RII mice demonstrated increased susceptibility to
induction of EAH, as demonstrated histologically and biochemically. This suggests that indeed the regulatory effects of TGF-
on T cells
are important in maintaining immune homeostasis within the liver.
TGF-
seems to be required for suppression of autoreactive T cells
infiltrating the liver.
![]() |
MATERIALS AND METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Generation and maintenance of hCD2-kT
RII mice.
The cDNA of the type II receptor lacking the cytoplasmic kinase domain
(
kT
RII) (7) was inserted in the SmaI site
of the human CD2 (hCD2) minilocus expression vector (56).
The expression cassette was excised by NotI/SalI
digestion, gel purified, and used for pronuclear microinjection of
fertilized eggs of strain FVB/N, essentially as described
(22). Offspring were biopsied at ears or tails and
analyzed for genotype by PCR using an hCD2-specific primer
[5'-TTTGTAGCCAGCTTCCTTCTG-3', corresponding to positions 243-263;
GenBank accession no. X07871 (32)] and a human TGF-
type II receptor-specific oligonucleotide
[5'-TGCACTCATCAGAGCTACAGG-3', corresponding to positions 272-252;
GenBank accession no. U52242 (50)].
Northern blot analysis.
Total RNAs from various tissues were isolated with TRI Reagent (Sigma,
Deisenhofen, Germany) according to the manufacturer's instructions.
Aliquots (~20 µg) of RNA were separated by electrophoresis using
1% agarose formaldehyde gels and were subsequently blotted onto nylon
membranes (Hybond N; Amersham, Braunschweig, Germany). For the analysis
of RNA expression of the transgenic mouse line designated line
2 (see RESULTS for descriptions of each line), 30 µg
of RNA were loaded for nonlymphoid organs to better demonstrate the
lack of transgene expression in these organs. Filters were processed at
high stringency as described (9) and were hybridized with
the 32P-labeled human TGF- type II receptor cDNA (920 bp). Before electrophoresis, ethidium bromide was added to the samples
to assess similar loading of RNA and the transfer efficiency of the RNA samples.
Separation of lymphoid cells. For the separation of B and T lymphocytes, splenocytes from 6-wk-old mice were marked with anti-mouse CD3-FITC or anti-mouse CD45R/B220-FITC MAb (BD Pharmingen, Heidelberg, Germany). MACS beads conjugated with anti-FITC antibodies were added, and cells were separated by using LS+ cell separation columns from Miltenyi Biotech (Bergisch Gladbach, Germany). B cells were removed in a first separation step, and T cells were further purified in a second separation step. Purity of T cells was assessed by FACS analysis and ranged between 90 and 95%.
FACS analysis. For assessment of the purity of cell separation, the FITC-marked cells were counterstained with anti-mouse CD19-PE or anti-mouse CD3-PE (BD Pharmingen). Spleen, thymic, and lymph node cells of transgenic mice and nontransgenic littermates were analyzed by using anti-mouse CD4-FITC, anti-mouse CD8-PE/FITC, anti-mouse CD62L-PE, and anti-mouse CD44-PE MAb (all from BD Pharmingen). FACS analysis was performed with a FACScan using CELL-quest software (Becton Dickinson, Heidelberg, Germany).
Cell culture and inhibition of IL-2 secretion.
Spleen cells were cultivated in RPMI 1640 medium (Biochrom, Berlin,
Germany) containing 5% FCS supplemented with penicillin (100 U/ml) and
streptomycin (100 µg/ml; Life Technologies, Eggenstein, Germany).
Cells (2 × 106 cells/ml) were plated and incubated with
different concentrations of human TGF-1 as indicated (Strathmann
Biotech, Hannover, Germany). After 12 h of cultivation, T cells
were separated and plated onto precoated 24-well plates (Greiner,
Frickenhausen, Germany). Antibody (10 µg/ml anti-mouse CD28 MAb; BD
Pharmingen) was added to the medium. For precoating, plates were
incubated at 4°C with 10 µg/ml anti-mouse CD3 MAb in 0.1 M sodium
phosphate buffer (pH 8.5) overnight. Cells were grown at 37°C in a
water-saturated atmosphere with 5% CO2 in air.
Supernatants were collected after 24 h and frozen in liquid nitrogen.
ELISA.
Concentrations of IL-2, IFN-, and IL-4 in cell culture supernatants
were measured by using mouse OptEIA ELISA sets (BD Pharmingen) according to the manufacturer's instructions. Immunoglobulin
subclasses in sera of mice were assayed by using the SBA clonotyping
system (Southern Biotechnology, Birmingham, AL).
Cell proliferation assay. Splenocytes were seeded at 5 × 105 cells/well in 96-well flat-bottom plates (Greiner) in RPMI medium supplemented with 5% FCS and antibiotics (as described in Cell culture and inhibition of IL-2 secretion) or in serum-free medium (PAN Biotech, Aidenbach, Germany). For cell stimulation, plates were precoated with anti-mouse CD3 MAb overnight, and anti-mouse CD28 MAb was added to the medium at a concentration of 10 µg/ml. Cells were incubated at 37°C in 5% CO2 for 72 h and pulsed with 2.5 µCi/well [3H]thymidine for the last 24 h of culture. Samples were harvested and counted in a Betaplate liquid scintillation counter (Wallac, Freiburg, Germany).
Immunization of mice. EAH was induced by immunizing mice with the 100,000-g supernatant from livers of wild-type syngenic mice in adjuvant basically as described (39). Briefly, for the preparation of liver antigen, the portal vein was cannulated and flushed with cold PBS. The liver was removed and homogenized in PBS containing aprotinin (Sigma) and trypsin inhibitor (Serva, Heidelberg, Germany) and centrifuged at 150 g for 10 min. The supernatant was subsequently centrifuged for 1 h at 100,000 g, resulting in the S-100 supernatant. The protein concentration was determined, and mice were immunized intraperitoneally with 2.5 mg of fresh S-100 protein emulsified in the same volume of complete Freund's adjuvant (Difco, Detroit, MI). Immunizations were done twice or three times in weekly intervals, and mice were bled and killed 2 wk after the last immunization. Mice of line 2 were used for induction of hepatitis.
Isolation of inflammatory cells from livers. Cell suspensions were generated from livers by using 40-µm cell strainers (Becton Dickinson). Cells from several livers were pooled, washed in Hanks' balanced salt solution, and resuspended in 100% Percoll (Amersham, Uppsala, Sweden). The suspension was overlaid with 40% Percoll and centrifuged, and the cells were recovered from the interphase. After being washed twice, cells were either used for flow cytometric analysis or cultured for 48 h in RPMI medium supplemented with 5% FCS and antibiotics for the analysis of the cytokine secretion profile. Tissue culture plates were precoated overnight with anti-CD3 MAb, and anti-CD28 MAb was added to the medium as described.
Histology. Selected tissues were fixed in 4% formalin and embedded in paraffin. Sections (2 µm) were stained with hematoxylin and eosin and analyzed. Elastica van Gieson staining was used for assessment of fibrosis. Cryostat sections (5 µm) were fixed in cold acetone and stained with hematoxylin and eosin.
Immunohistochemical staining was performed after endogenous peroxidase was blocked with methanol and hydrogen peroxide. For the staining of T cells, anti-CD3 MAb (Novocastra, Newcastle, UK), biotinylated anti-rat antibody (BD Pharmingen), and the Vectastain ABC kit (Vector Laboratories, Burlingame, CA) were used. Staining was enhanced with ammonium nickel sulfate. For the staining of B cells, anti CD45R/B220 MAb (BD Pharmingen) was used as primary antibody. Granulocytes were stained by using the specific Naphtole-AS-D-Chloracetate-Esterase kit (Sigma) according to the manufacturer's instructions. All visible portal tracts of a liver section were evaluated by a pathologist in a blinded fashion and graded as follows: grade 0, normal histomorphology; grade 1, minor inflammatory infiltrates with occasional liver cell necrosis; grade 2, moderate liver damage with inflammatory infiltrates and focal necroses; and grade 3, extensive infiltrates in portal tracts and lobules accompanied by diffusely distributed liver cell necroses. At least two separate sections were assessed per liver. For single animals, multiple cryostat sections were assessed from different parts of the liver.Statistical analysis. Means ± SE are given. For comparison of groups, the Wilcoxon two-sample test or the Mann-Whitney rank sum test was applied. P < 0.05 was considered significant.
![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Generation of hCD2-kT
RII mice.
To interrupt TGF-
signaling in T cells, we inserted the cDNA of a
truncated TGF-
type II receptor (
kT
RII), which lacks the
intracellular kinase domain, into the human CD2 minilocus expression
vector (Fig. 1A). The hCD2
promoter/enhancer drives the copy number-dependent expression in T
cells (56). We obtained three founder animals that were
fertile and gave rise to three transgenic lines, which were designated
according to the Institute for Laboratory Animal Research
guidelines as TgN(CD2
kT
RII)1Mbl, TgN(CD2
kT
RII)2Mbl, and
TgN(CD2
kT
RII)4Mbl. These transgenic lines are abbreviated from
here on as lines 1, 2, and 4.
Heterozygous animals of all three lines showed no macroscopic
abnormalities. Mice were observed until the age of 9 mo. Examination of
hematoxylin- and eosin-stained sections of various organs and tissues
including the liver, lung, heart, spleen, kidneys, and intestine
revealed normal histology (data not shown).
|
Phenotypic analysis of hCD2-kT
RII mice.
The cell surface phenotypes of thymus, spleen (Fig.
2; Table
1). and lymph node cells (data not
shown) were analyzed in mice up to the age of 15 wk and revealed no
major differences between transgenic and nontransgenic mice.
Specifically, there was no difference in total splenic cell numbers or
in the CD4/CD8 ratio in spleen or lymph nodes. Staining of CD4- and
CD8-positive splenic and lymph node T cells for CD62L and CD44
suggested normal numbers of naive and memory T cells.
|
|
|
|
Increased susceptibility to EAH in hCD2-kT
RII mice and
characterization of hepatic infiltrates.
To test whether loss of TGF-
signaling might influence the
susceptibility to EAH, we induced EAH by repeated injection with syngenic liver homogenate in complete Freund's adjuvant. Liver histology was analyzed 2 wk after the last immunization. Wild-type mice
showed only minor granulocytic infiltrates restricted to the portal
tracts (Fig.
5A). In
contrast, transgenic mice showed portal and periportal leukocytic
infiltrates with hepatocellular necroses (Fig. 5, B and
C). Immunohistochemical staining was performed to further
characterize the phenotype of cells infiltrating the liver. A
significant amount of CD3-positive T cells (Fig. 5D) and
some B cells (Fig. 5F) were seen within the hepatic
infiltrate. Scattered T cells were also seen within the hepatic lobule.
The majority of cells at this stage of hepatitis induction were
granulocytes (Fig. 5E). The severity of hepatitis was graded
in a blinded fashion, and at least two separate sections were analyzed
per animal.
|
|
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The results presented demonstrate that impairment of the
suppressive effects exerted by TGF- on T cells can facilitate or augment autoimmune inflammatory liver disease. The important role of
TGF-
in immune homeostasis has been previously shown in TGF-
1 knockout mice that develop a multifocal inflammatory disorder (29, 49). In these mice, lack of TGF-
1 leads to a
number of abnormalities, including upregulation of major
histocompatability complex (MHC) class I and II
(17), dysregulation of hematopoiesis (55),
and abnormal development as demonstrated by a 50% embryonic lethality
(30). Furthermore, TGF-
1 knockout mice still express TGF-
2 and 3, which might, in part, compensate for the lack of TGF-
1.
The importance of T and B lymphocytes in the development of the
autoimmune disorder observed in TGF-1 knockout mice has been suggested by studies using TGF-
1 knockout SCID mice
(13) and TGF-
1/MHC class II knockout mice
(33). Yet the multifocal inflammatory disorder
spontaneously developing in TGF-
1 knockout mice also affects the
liver and leads to early death. Together with the above-mentioned
restrictions of delineating the effects of TGF-
to a certain cell
type, TGF-
1 knockout mice seemed unsuitable for the study of the
role of TGF-
signaling in T cells in the maintenance of immune
homeostasis within the liver.
We therefore generated transgenic mice that overexpress a
dominant-negative TGF- type II receptor in T cells. The impairment of TGF-
signaling in T cells did not lead to spontaneous
autoimmunity, as observed in the TGF-
1 knockout model and as
recently described for another model of T cell-specific loss of TGF-
signaling (19). This might be due to the FVB/N mouse
strain we used in our experiments, because C57BL/6 mice seem to be more
prone to immune dysregulation (38). Indeed, the importance
of the genetic background in the development of autoimmune disease has
been demonstrated by the strain-dependent phenotypes of IL-2 knockout
mice (46, 47). For example, Fc
RIIB knockout mice on the
C57BL/6 background develop a lethal, lupus-like syndrome, whereas mice
on the BALB/c background present with a normal phenotype
(6). Very recently, strain specificity could be
demonstrated for the development of hepatic inflammation in TGF-
1
knockout mice bred to the BALB/c or to a hybrid 129/CF-1 background
(20).
Conflicting results have emerged from the impairment of TGF-
signaling in T cells in three different models recently described (19, 40, 43). Expression of a dominant-negative TGF-
type II receptor under the control of the CD4 promoter lacking the CD8
silencer has resulted in spontaneous autoimmunity with lymphocytic infiltrates in various organs, including the liver (19).
In another model using the hCD2 promoter, mice developed a CD8+ T cell
lymphoproliferative disorder without any inflammatory component (40). In contrast, overexpression of Smad7, which is
inhibitory for several members of the TGF-
superfamily, did not
produce a spontaneous phenotype (43). The reason for the
differences observed remain to be elucidated but might relate to
different promoter specificity and expression during thymic development as well as differences in the degree of impairment of TGF-
signaling and differences in the genetic background. Although we were able to
uncouple IL-2 production in T cells of line 2 from
TGF-
1-mediated suppression in our model, it was not designed for
complete abrogation of TGF-
signaling to analyze the role of TGF-
in the initiation phase of EAH.
Since our transgenic mice did not show spontaneous histological
abnormalities, they provide a suitable model to study the regulatory
role of TGF- on T cells in the induction phase of autoimmune liver
injury. We induced EAH by immunizing mice with syngenic liver
homogenate in complete adjuvant. This has been shown to result in
autoimmune liver injury with varying intensity in different mouse
strains (38). Only minimal biochemical or histological
signs of hepatitis were detected in nontransgenic FVB/N mice after
three immunizations with liver homogenate in adjuvant, demonstrating
the relative resistance of this mouse strain to EAH. In contrast,
transgenic mice developed portal and periportal leukocytic infiltrates
with hepatocellular necroses and significantly elevated
aminotransferase levels, indicating that TGF-
signaling in T cells
is required for maintenance of immune regulation in autoimmune liver injury.
A significant proportion of liver-infiltrating cells were T cells, the
proportion in transgenic mice being about twice as high as in wild-type
mice. Stimulated in vitro by anti-CD3/28 cross-linking, the
inflammatory cells isolated from transgenic livers produced more
IFN- and less IL-4 than their wild-type counterparts. IFN-
production by liver-infiltrating T cells has been made responsible for
the phenotype of necroinflammatory hepatitis recently described for
TGF-
1 knockout mice on the BALB/c background (20).
Impaired TGF-
signaling in T cells might be partially responsible
for the increased IFN-
production observed in this model. The
importance of IFN-
in the pathogenesis of liver injury has been
demonstrated in transgenic mice with increased IFN-
production in
the liver (51) and in the T cell-dependent hepatitis models induced by injection of concanavalin A (31) or
hepatitis B virus surface antigen (45). However, there is
no direct proof of IFN-
being directly involved in the pathogenesis
of EAH and the more severe reaction observed in our transgenic model.
In addition, IFN- has been detected within the inflammatory lesions
of patients with AIH (23). EAH shares several other features with human AIH periportal hepatitis, such as lymphocytic infiltrates (27, 38, 52), T cell reactivity to liver
antigens (38), autoantibody production (35),
and response to immunosuppressive therapy (36). In
patients with AIH, strong TGF-
1 expression can be found in inflamed
livers, which seems to correlate with disease activity
(4). It could thus be speculated that TGF-
in the
inflamed liver is at least in part produced to suppress infiltrating
autoreactive T cells.
In addition to the increased susceptibility to induction of EAH, we
demonstrated that in hCD2-kT
RII mice lymphocytes produce higher
amounts of Th1-like cytokines. Baseline IL-2 production of line 2 T cells was nearly three times the amount of wild-type T cells.
Transgenic splenocytes secreted more IFN-
on CD3/CD28 cross-linking,
which was also shown by using serum-free medium, thus eliminating the
possible inhibitory effect of serum-derived TGF-
on wild-type
splenocytes. These findings are in accordance with the study by Gorelik
and Flavell (19), who demonstrated that, in the absence of
TGF-
signaling, most of the T cells differentiated into effector cells.
Although our study and others demonstrate the importance of T cells in
EAH, a possible contribution of B cells cannot be excluded. In our
transgenic animals, increased levels of serum IgA were found. TGF-
is an important immunoglobulin class switch factor for IgA
(26), and decreased serum IgA-levels can be found in TGF-
knockout mice (53). TGF-
signaling in B cells
seems to be essential for the secretion of IgA, since a recently
published conditional mutagenesis of the TGF-
type II receptor in B
cells was associated with a virtually complete absence of serum IgA (8). In this context it is important to note that weak
expression of the transgene in the B cell fraction of our transgenic
mice cannot be excluded. However, the fact that serum IgA levels are increased in our transgenic animals shows that TGF-
signaling in B
cells is functional. This is consistent with the finding that only
strong overexpression of a dominant-negative type II receptor over the
endogenous receptor impairs signal transduction. It was suggested that
T cells with loss of TGF-
signaling might stimulate IgA secretion of
B cells by increased TGF-
production (19).
The results of this study demonstrate the important role of TGF- in
counteracting T lymphocyte-mediated liver injury. TGF-
signaling in
T cells is necessary to suppress infiltration of the liver on EAH
induction. Overexpression of TGF-
occurring in active AIH is thus
likely to be an important regulatory mechanism toward reestablishing
homeostasis, albeit at the expense of increased fibrogenesis,
eventually leading to cirrhosis.
![]() |
ACKNOWLEDGEMENTS |
---|
We thank Karin Nicol and Marina Snetkova for excellent technical assistance.
![]() |
FOOTNOTES |
---|
This work was supported by the Deutsche Forschungsgemeinschaft, project C3, Sonderforschungs Bereich 548, and MAIFOR, Faculty of Medicine, University of Mainz and the Boehringer-Ingelheim Foundation.
Address for reprint requests and other correspondence: M. Blessing, I. Dept. of Medicine, Johannes-Gutenberg Univ., Obere Zahlbacherstr. 63, 55131 Mainz, Germany (E-mail:blessing{at}mail.uni-mainz.de)
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
First published December 4, 2002;10.1152/ajpgi.00286.2002
Received 16 July 2002; accepted in final form 20 November 2002.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Ahuja, SS,
Paliogianni F,
Yamada H,
Balow JE,
and
Boumpas DT.
Effect of transforming growth factor-beta on early and late activation events in human T cells.
J Immunol
150:
3109-3118,
1993
2.
Attisano, L,
Carcamo J,
Ventura F,
Weis FM,
Massague J,
and
Wrana JL.
Identification of human activin and TGF beta type I receptors that form heteromeric kinase complexes with type II receptors.
Cell
75:
671-680,
1993[ISI][Medline].
3.
Attisano, L,
Wrana JL,
Lopez-Casillas F,
and
Massague J.
TGF-beta receptors and actions.
Biochim Biophys Acta
1222:
71-80,
1994[ISI][Medline].
4.
Bayer, EM,
Herr W,
Kanzler S,
Waldmann C,
Meyer zum Büschenfelde KH,
Dienes HP,
and
Lohse AW.
Transforming growth factor-beta1 in autoimmune hepatitis: correlation of liver tissue expression and serum levels with disease activity.
J Hepatol
28:
803-811,
1998[ISI][Medline].
5.
Bedossa, P,
and
Paradis V.
Transforming growth factor-beta (TGF-beta): a key-role in liver fibrogenesis.
J Hepatol
22:
37-42,
1995[ISI][Medline].
6.
Bolland, S,
and
Ravetch JV.
Spontaneous autoimmune disease in Fc(gamma)RIIB-deficient mice results from strain-specific epistasis.
Immunity
13:
277-285,
2000[ISI][Medline].
7.
Brand, T,
MacLellan WR,
and
Schneider MD.
A dominant-negative receptor for type beta transforming growth factors created by deletion of the kinase domain.
J Biol Chem
268:
11500-11503,
1993
8.
Cazac, BB,
and
Roes J.
TGF-beta receptor controls B cell responsiveness and induction of IgA in vivo.
Immunity
13:
443-451,
2000[ISI][Medline].
9.
Church, GM,
and
Gilbert W.
Genomic sequencing.
Proc Natl Acad Sci USA
81:
1991-1995,
1984[Abstract].
10.
Czaja, AJ,
Ludwig J,
Baggenstoss AH,
and
Wolf A.
Corticosteroid-treated chronic active hepatitis in remission: uncertain prognosis of chronic persistent hepatitis.
N Engl J Med
304:
5-9,
1981[Abstract].
11.
Czaja, AJ,
Manns MP,
McFarlane IG,
and
Hoofnagle JH.
Autoimmune hepatitis: the investigational and clinical challenges.
Hepatology
31:
1194-1200,
2000[Medline].
12.
Derynck, R,
Zhang Y,
and
Feng XH.
Smads: transcriptional activators of TGF-beta responses.
Cell
95:
737-740,
1998[ISI][Medline].
13.
Diebold, RJ,
Eis MJ,
Yin M,
Ormsby I,
Boivin GP,
Darrow BJ,
Saffitz JE,
and
Doetschman T.
Early-onset multifocal inflammation in the transforming growth factor beta 1-null mouse is lymphocyte mediated.
Proc Natl Acad Sci USA
92:
12215-12219,
1995[Abstract].
14.
Ebner, R,
Chen RH,
Lawler S,
Zioncheck T,
and
Derynck R.
Determination of type I receptor specificity by the type II receptors for TGF-beta or activin.
Science
262:
900-902,
1993[ISI][Medline].
15.
Espevik, T,
Waage A,
Faxvaag A,
and
Shalaby MR.
Regulation of interleukin-2 and interleukin-6 production from T-cells: involvement of interleukin-1 beta and transforming growth factor-beta.
Cell Immunol
126:
47-56,
1990[ISI][Medline].
16.
Fargeas, C,
Wu CY,
Nakajima T,
Coxm D,
Nutman T,
and
Delespesse G.
Differential effect of transforming growth factor beta on the synthesis of Th1- and Th2-like lymphokines by human T lymphocytes.
Eur J Immunol
22:
2173-2176,
1992[ISI][Medline].
17.
Geiser, AG,
Letterio JJ,
Kulkarni AB,
Karlsson S,
Roberts AB,
and
Sporn MB.
Transforming growth factor beta 1 (TGF-beta 1) controls expression of major histocompatability genes in the postnatal mouse: aberrant histocompatability antigen expression in the pathogenesis of the TGF- beta 1 null mouse phenotype.
Proc Natl Acad Sci USA
90:
9944-9948,
1993[Abstract].
18.
Gorelik, L,
Fields PE,
and
Flavell RA.
Cutting edge: TGF-beta inhibits Th type 2 development through inhibition of GATA-3 expression.
J Immunol
165:
4773-4777,
2000
19.
Gorelik, L,
and
Flavell RA.
Abrogation of TGFbeta signaling in T cells leads to spontaneous T cell differentiation and autoimmune disease.
Immunity
12:
171-181,
2000[ISI][Medline].
20.
Gorham, JD,
Lin JT,
Sung JL,
Rudner LA,
and
French MA.
Genetic regulation of autoimmune disease: BALB/c background TGF-beta1-deficient mice develop necroinflammatory IFN-gamma-dependent hepatitis.
J Immunol
166:
6413-6422,
2001
21.
Heath, VL,
Murphy EE,
Crain C,
Tomlinson MG,
and
O'Garra A.
TGF-beta1 down-regulates Th2 development and results in decreased IL-4-induced STAT6 activation and GATA-3 expression.
Eur J Immunol
30:
2639-2649,
2000[ISI][Medline].
22.
Hogan, BLM,
Costatini F,
and
Lacy E.
Manipulating the Mouse Embryo. A Laboratory Manual. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory, 1986.
23.
Hussain, MJ,
Mustafa A,
Gallati H,
Mowat AP,
Mieli-Vergani G,
and
Vergani D.
Cellular expression of tumour necrosis factor-alpha and interferon-gamma in the liver biopsies of children with chronic liver disease.
J Hepatol
21:
816-821,
1994[ISI][Medline].
24.
Kanzler, S,
Lohse AW,
Keil A,
Henninger J,
Dienes HP,
Schirmacher P,
Rose-John S,
Meyer zum Büschenfelde KH,
and
Blessing M.
TGF-1 in liver fibrosis: an inducible transgenic mouse model to study liver fibrogenesis.
Am J Physiol Gastrointest Liver Physiol
276:
G1059-G1068,
1999
25.
Kehrl, JH,
Wakefield LM,
Roberts AB,
Jakowlew S,
Alvarez-Mon M,
Derynck R,
Sporn MB,
and
Fauci AS.
Production of transforming growth factor beta by human T lymphocytes and its potential role in the regulation of T cell growth.
J Exp Med
163:
1037-1050,
1986[Abstract].
26.
Kim, PH,
and
Kagnoff MF.
Transforming growth factor-beta 1 is a costimulator for IgA production.
J Immunol
144:
3411-3416,
1990
27.
Kohda, H,
Sekiya C,
Kanai M,
Yoshida Y,
Uede T,
Kikuchi K,
and
Namiki M.
Flow cytometric and functional analysis of mononuclear cells infiltrating the liver in experimental autoimmune hepatitis.
Clin Exp Immunol
82:
473-478,
1990[ISI][Medline].
28.
Krawitt, EL.
Autoimmune hepatitis.
N Engl J Med
334:
897-903,
1996
29.
Kulkarni, AB,
Huh CG,
Becker D,
Geiser A,
Lyght M,
Flanders KC,
Roberts AB,
Sporn MB,
Ward JM,
and
Karlsson S.
Transforming growth factor beta 1 null mutation in mice causes excessive inflammatory response and early death.
Proc Natl Acad Sci USA
90:
770-774,
1993[Abstract].
30.
Kulkarni, AB,
Ward JM,
Yaswen L,
Mackall CL,
Bauer SR,
Huh CG,
Gress RE,
and
Karlsson S.
Transforming growth factor-beta 1 null mice. An animal model for inflammatory disorders.
Am J Pathol
146:
264-275,
1995[Abstract].
31.
Kusters, S,
Gantner F,
Kunstle G,
and
Tiegs G.
Interferon-gamma plays a critical role in T cell-dependent liver injury in mice initiated by concanavalin A.
Gastroenterology
111:
462-471,
1996[ISI][Medline].
32.
Lang, G,
Wotton D,
Owen MJ,
Sewell WA,
Brown MH,
Mason DY,
Crumpton MJ,
and
Kioussis D.
The structure of the human CD2 gene and its expression in transgenic mice.
EMBO J
7:
1675-1682,
1988[Abstract].
33.
Letterio, JJ,
Geiser AG,
Kulkarni AB,
Dang H,
Kong L,
Nakabayashi T,
Mackall CL,
Gress RE,
and
Roberts AB.
Autoimmunity associated with TGF-beta1-deficiency in mice is dependent on MHC class II antigen expression.
J Clin Invest
98:
2109-2119,
1996
34.
Letterio, JJ,
and
Roberts AB.
Regulation of immune responses by TGF-beta.
Annu Rev Immunol
16:
137-161,
1998[ISI][Medline].
35.
Lohse, AW,
Brunner S,
Kyriatsoulis A,
Manns M,
and
Meyer zum Büschenfelde KH.
Autoantibodies in experimental autoimmune hepatitis.
J Hepatol
14:
48-53,
1992[ISI][Medline].
36.
Lohse, AW,
Dienes HP,
and
Meyer zum Büschenfelde KH.
Suppression of murine experimental autoimmune hepatitis by T-cell vaccination or immunosuppression.
Hepatology
27:
1536-1543,
1998[ISI][Medline].
37.
Lohse, AW,
Kogel M,
and
Meyer zum Büschenfelde KH.
Evidence for spontaneous immunosuppression in autoimmune hepatitis.
Hepatology
22:
381-388,
1995[ISI][Medline].
38.
Lohse, AW,
Manns M,
Dienes HP,
Meyer zum Büschenfelde KH,
and
Cohen IR.
Experimental autoimmune hepatitis: disease induction, time course and T-cell reactivity.
Hepatology
11:
24-30,
1990[ISI][Medline].
39.
Lohse, AW,
and
Meyer zum Büschenfelde KH.
Experimental hepatitis.
In: Autoimmune Disease Models, edited by Cohen IR,
and Miller A.. San Diego: Academic, 1994, p. 191-200.
40.
Lucas, PJ,
Kim SJ,
Melby SJ,
and
Gress RE.
Disruption of T cell homeostasis in mice expressing a T cell-specific dominant negative transforming growth factor beta II receptor.
J Exp Med
191:
1187-1196,
2000
41.
Miyazono, K,
Ten Dijke P,
Ichijo H,
and
Heldin CH.
Receptors for transforming growth factor-beta.
Adv Immunol
55:
181-220,
1994[ISI][Medline].
42.
Mule, JJ,
Schwarz SL,
Roberts AB,
Sporn MB,
and
Rosenberg SA.
Transforming growth factor-beta inhibits the in vitro generation of lymphokine-activated killer cells and cytotoxic T cells.
Cancer Immunol Immunother
26:
95-100,
1988[ISI][Medline].
43.
Nakao, A,
Miike S,
Hatano M,
Okumura K,
Tokuhisa T,
Ra C,
and
Iwamoto I.
Blockade of transforming growth factor beta/Smad signaling in T cells by overexpression of Smad7 enhances antigen-induced airway inflammation and airway reactivity.
J Exp Med
192:
151-158,
2000
44.
Ogawa, M,
Mori Y,
Mori T,
Ueda S,
Yoshida H,
Kato I,
Iesato K,
Wakashin Y,
Azemoto R,
Wakashin M,
Okuda K,
and
Ohto M.
Adoptive transfer of experimental autoimmune hepatitis in micecellular interaction between donor and recipient mice.
Clin Exp Immunol
73:
276-282,
1988[ISI][Medline].
45.
Ohta, A,
Sekimoto M,
Sato M,
Koda T,
Nishimura S,
Iwakura Y,
Sekikawa K,
and
Nishimura T.
Indispensable role for TNF-alpha and IFN-gamma at the effector phase of liver injury mediated by Th1 cells specific to hepatitis B virus surface antigen.
J Immunol
165:
956-961,
2000
46.
Sadlack, B,
Merz H,
Schorle H,
Schimpl A,
Feller AC,
and
Horak I.
Ulcerative colitis-like disease in mice with a disrupted interleukin-2 gene.
Cell
75:
253-261,
1993[ISI][Medline].
47.
Sadlack, B,
Lohler J,
Schorle H,
Klebb G,
Haber H,
Sickel E,
Noelle RJ,
and
Horak I.
Generalized autoimmune disease in interleukin-2-deficient mice is triggered by an uncontrolled activation and proliferation of CD4+ T cells.
Eur J Immunol
25:
3053-3059,
1995[ISI][Medline].
48.
Smyth, MJ,
Strobl SL,
Young HA,
Ortaldo JR,
and
Ochoa AC.
Regulation of lymphokine-activated killer activity and pore-forming protein gene expression in human peripheral blood CD8+ T lymphocytes. Inhibition by transforming growth factor-beta.
J Immunol
146:
3289-3297,
1991
49.
Shull, MM,
Ormsby I,
Kier AB,
Pawlowski S,
Diebold RJ,
Yin M,
Allen R,
Sidman C,
Proetzel G,
and
Calvin D.
Targeted disruption of the mouse transforming growth factor-beta 1 gene results in multifocal inflammatory disease.
Nature
359:
693-699,
1992[ISI][Medline].
50.
Takenoshita, S,
Hagiwara K,
Nagashima M,
Gemma A,
Bennett WP,
and
Harris CC.
The genomic structure of the gene encoding the human transforming growth factor beta type II receptor (TGF-beta RII).
Genomics
36:
341-344,
1996[ISI][Medline].
51.
Toyonaga, T,
Hino O,
Sugai S,
Wakasugi S,
Abe K,
Shichiri M,
and
Yamamura K.
Chronic active hepatitis in transgenic mice expressing interferon-gamma in the liver.
Proc Natl Acad Sci USA
91:
614-618,
1994[Abstract].
52.
Tsunematsu, S,
Saito H,
Tada S,
Ebinuma H,
Tsuchiya M,
Kumagai N,
Morizane T,
Nomura T,
and
Ishii H.
Susceptibility of experimental autoimmune hepatitis in transgenic mice overexpressing the c-H-ras gene.
J Gastroenterol Hepatol
12:
319-324,
1997[ISI][Medline].
53.
Van Ginkel, FW,
Wahl SM,
Kearney JF,
Kweon MN,
Fujihashi K,
Burrows PD,
Kiyono H,
and
McGhee JR.
Partial IgA-deficiency with increased Th2-type cytokines in TGF-beta 1 knockout mice.
J Immunol
163:
1951-1957,
1999
54.
Wrana, JL,
Attisano L,
Wieser R,
Ventura F,
and
Massague J.
Mechanism of activation of the TGF-beta receptor.
Nature
370:
341-347,
1994[ISI][Medline].
55.
Yaswen, L,
Kulkarni AB,
Fredrickson T,
Mittleman B,
Schiffman R,
Payne S,
Longenecker G,
Mozes E,
and
Karlsson S.
Autoimmune manifestations in the transforming growth factor-beta 1 knockout mouse.
Blood
87:
1458-1465,
1996
56.
Zhumabekov, T,
Corbella P,
Tolaini M,
and
Kioussis D.
Improved version of a human CD2 minigene based vector for T cell-specific expression in transgenic mice.
J Immunol Methods
185:
133-140,
1995[ISI][Medline].
|
HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Visit Other APS Journals Online |