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Nuffield Department of Surgery, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Selection of CD4+ T cells expressing CD25
(IL-2R
chain) has been shown to enrich for immunoregulatory activity
(15). Although CD25+ cells represent
a minor subset (5–10%) of CD4+ T cells in naive
mice and CD25 is generally regarded as an activation marker, depletion
of CD25+ cells in normal mice leads to autoimmune
disease (15). Moreover, the adoptive transfer of
CD25+CD4+ T cells from
normal mice can prevent autoimmune disease caused by pathogenic
effector cells (16, 17, 18, 19, 20). Although the mechanisms of immune
regulation mediated by
CD25+CD4+ T cells are not
fully characterized, in vivo studies using neutralizing and blocking
Abs have highlighted the role of the cytokines IL-10 (21, 22) and TGF-
(19) and the CD28 homolog
CTLA-4 (CD152; Refs. 19 and 23).
We have recently shown that CD45RBlowCD4+ and CD25+CD4+ T cell subpopulations isolated from animals with long-term surviving allografts can regulate rejection of skin allografts mediated by CD45RBhighCD4+ T cells from naive mice (14), indicating that long-term operational tolerance in this system is dependent on active immune regulation. Similar results have recently been reported by Gregori et al. (24) using CD25+CD4+ T cells from mice with long-term islet allografts. The possibility that specific regulatory T cells could be generated before transplantation and afford the graft protection from the outset is appealing. Furthermore, if such cells can expand by an "infective" process (25), it might be possible to achieve the tantalizing goal of lifelong operational tolerance without the need for prolonged immunosuppression. An understanding of the mechanism of such regulation will play a vital role in the development of such tolerogenic strategies.
Preliminary evidence that regulatory cells develop as a consequence of pretreatment with donor alloantigen in combination with anti-CD4 therapy was initially provided by the finding that adoptive transfer of cells from pretreated but untransplanted animals into naive recipients resulted in prolongation of cardiac graft survival (26). The hypothesis that regulation in this system is CD4 dependent was demonstrated by the fact that naive leukocytes are unable to break the unresponsive state unless putative regulatory cells are targeted by the addition of depleting anti-CD4 Ab (10).
In this study, we investigated the hypothesis that infusion of donor
alloantigen under the cover of an anti-CD4 Ab leads to the
development of CD4+ regulatory T cells that can
be enriched on the basis of CD25 expression. We demonstrate that this
pretreatment strategy generates alloantigen-specific
CD25+CD4+ T cells with the
ability to regulate rejection of skin allografts. Prior exposure to
anti-CD4 Ab and donor alloantigen increases the proportion of
CD4+CD25+ T cells that
express CD122 (IL-2R). Furthermore we demonstrate that blockade of
both CTLA-4 and IL-10 pathways abrogates the immune regulation of
alloresponses mediated by
CD25+CD4+ T cells, thus
providing evidence that both CTLA-4 and IL-10 play an important role in
this mechanism of immune regulation in vivo.
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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CBA.Ca (CBA, H-2k), C57BL/10 (B10, H-2b), BALB/c (H-2d), and CBA Rag 1-/- (H-2k) (kindly provided by Dr. D. Kioussis, Division of Molecular Immunology, National Institute for Medical Research, Mill Hill, London, U.K.) mice were obtained from and housed in the Biomedical Services Unit of the John Radcliffe Hospital (Oxford, U.K.). Sex-matched mice between 6 and 12 wk of age at the time of first experimental procedure were used in all experiments.
Reagents and mAbs
The following reagents were used for flow cytometry and cell
isolation: TIB120 (anti-class II; American Type Culture
Collection, Manassas, VA), RM4-5 (anti-CD4) CyChrome, RM4-5
(anti-CD4) PerCP, TM-1 (anti-CD122) FITC, 16A
(anti-CD45RB) PE, 7D4 (anti-CD25) biotin, streptavidin-PE, and
streptavidin-allophycocyanin were purchased from BD PharMingen
(San Diego, CA). The hybridomas YTA3.1.2, (anti-CD4; Ref.
27), YTS177.9 (anti-CD4; Ref. 25), and
YTS169 (anti-CD8; Ref. 25) were kindly provided by
Prof. H. Waldmann (Sir William Dunn School of Pathology, Oxford, U.K.).
The following mAbs were used for in vivo experiments: anti-mouse
CTLA-4 (clone UC10-4F10-11; 0.8 mg/week; Ref. 28 ;
hybridoma kindly provided by Dr. J. Bluestone, Diabetes Center,
University of California, San Francisco, CA), purified hamster IgG (0.8
mg/week; Jackson ImmunoResearch Laboratories, West Grove, PA), 1B1.2
(rat IgG1; 1 mg at time of cell transfer, 0.5 mg/week thereafter), a
blocking mAb reactive with mouse IL-10R (29), and GL113
(rat IgG1; 1 mg at time of cell transfer, 0.5 mg/week thereafter; Ref.
30), an isotype control mAb reactive with
-galactosidase.
Pretreatment protocol
Adult CBA mice received 200 µg of the anti-CD4 mAb YTS177
i.v. on days -28 and -27. On day -27, they also received 250 µl of
B10 (donor-specific transfusion
(DST)3) or BALB/c
(third-party) blood i.v. Spleens were harvested on day 0 for cell
isolation (Fig. 1
).
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T cell-deficient (T cell-depleted (Ref. 14) or Rag1-/-) mice either were reconstituted i.v. with fractionated T cells or remained untreated. The day after reconstitution, all mice received a B10 skin graft. Full-thickness tail skin was transplanted to graft beds prepared on the flanks of recipient mice. Grafts were monitored two to three times per week, and graft rejection was defined by complete destruction of the skin. Allograft survival between any two groups was compared by the log-rank sum test (31) using software developed and kindly provided by Dr. S. Cobbold (Sir William Dunn School of Pathology).
Cell purification and adoptive transfer
CD45RBhighCD4+ T cells were isolated from lymph nodes and spleens of naive CBA mice, and CD25+CD4+ T cells were obtained from spleens of animals pretreated with the YTS177/DST-tolerizing protocol or the relevant control protocol.
Lymph nodes and spleens were harvested and single cell suspensions were prepared. After red cell lysis, the cells were resuspended in PBS/1% BSA at 2 x 108/ml and were then incubated with YTS169 (200 µg/ml) and TIB120 (100 µg/ml) for 20 min at 4°C to deplete CD8+ and class II+ cells, respectively. The cell suspension was then washed and added to sheep anti-rat-coated Dynabeads (Dynal Biotech, Oslo, Norway) at a ratio of one bead per cell and this was then incubated on a rotating wheel at 4°C for 15 min. Negative cells were isolated by magnetic separation, counted, resuspended to 2 x 108 cells/ml, and stained with mAbs specific for CD4, CD45RB, or CD25 for 20 min. Cells were fractionated into CD45RBhighCD4+ or CD25+CD4+ and CD25-CD4+ fractions by cell sorting using a FACSVantage (BD Biosciences, Mountain View, CA). The CD45RBhigh population was defined as the brightest staining 40% of CD4+ T cells. On reanalysis, all populations were >95% pure. Each experiment contained minimally reconstituted (MR)-only mice to validate the efficacy of the CD45RBhigh effector population.
Flow cytometric analysis
All incubation steps were conducted for 30 min at 4°C. Single cell splenocyte suspensions were prepared, erythrocytes removed by hypotonic lysis, and the cells were resuspended in FACS buffer consisting of PBS supplemented with 2% FCS (PAA Laboratories, Linz, Austria) and 0.02% sodium azide (Sigma-Aldrich, St. Louis, MO). The cells were then incubated with Abs for cell surface staining (CD122-FITC, CD4-PerCP, and CD25-biotin), washed, incubated with streptavidin-allophycocyanin, washed again, and fixed by incubating in PBS containing 4% (v/v) formaldehyde (Sigma-Aldrich). For CTLA-4 staining, cells were incubated in permeabilization buffer consisting of FACS buffer supplemented with 0.5% saponin (Sigma-Aldrich) for 30 min and were then washed and incubated with CTLA-4-PE Ab for intracellular staining. The cells were washed, fixed in PBS containing 2% (v/v) formaldehyde, and stored at 4°C until acquisition. Data were acquired using a FACSort and were analyzed using the CellQuest software package (BD Biosciences, Oxford, U.K.). Statistical analysis was performed using the two-tailed paired t test.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Previous work from our laboratory has demonstrated that mice exhibiting operational tolerance to donor alloantigens in vivo contain CD4+ regulatory T cells that can be enriched on the basis of low expression of CD45RB or expression of CD25 (14). In the present study, we examined the induction phase of tolerance to provide an insight into the development of these regulatory populations and explore their mechanisms of action.
CD45RBhighCD4+ T cells
(1 x 105) from naive animals
reconstitute acute skin graft rejection when infused into T
cell-deficient mice (median survival time (MST) = 22.5 days,
n = 8; Fig. 2). These
animals are referred to as MR mice. Unreconstituted but grafted T
cell-deficient mice all accepted their skin grafts over 100 days (data
not shown). To investigate the ability of putative regulatory T cells
to prevent skin graft rejection, fractionated populations were
cotransferred with 1 x 105
CD45RBhighCD4+ T cells.
Cotransfer of 5 x 105
CD25+CD4+ T cells isolated
from mice 28 days after pretreatment with YTS177/DST prevented
rejection mediated by the CD45RBhigh cells with
five of six mice accepting their skin grafts over 100 days (MST >
100 days, n = 6, p < 0.05 vs MR mice;
Fig. 2). These surviving grafts were between 90 and 100% of their
original size, had no signs of tissue necrosis, and showed dense hair
growth indicating the efficiency of regulation in this system. To
determine whether the regulatory cells were only contained in the
CD25+ fraction, MR mice were infused with 5
x 105
CD25-CD4+ T cells from
YTS177/DST-pretreated mice. This resulted in the rapid rejection of B10
skin grafts (MST = 10 days, p < 0.01 vs MR mice
reconstituted with 5 x 105
CD25+CD4+ T cells from
YTS177/DST pretreated animals; Fig. 2), demonstrating that at these
cell numbers, CD25-CD4+ T
cells from pretreated mice were unable to regulate rejection.
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To investigate whether the regulation in this system was
alloantigen specific, we isolated
CD25+CD4+ T cells from mice
pretreated with third-party (BALB/c) blood under the cover of YTS177.
Cotransfer of 5 x 105
CD25+CD4+ T cells isolated
from these mice with 1 x 105
CD45RBhighCD4+ T cells
(from naive animals) resulted in acute rejection of B10 skin grafts
(MST = 19 days, p < 0.05 vs 177/DST (B10 blood)
pretreated mice; Fig. 2
), demonstrating that regulation in this system
is an alloantigen-specific phenomenon.
Generation of regulatory CD25+CD4+ T cells requires the simultaneous presence of donor alloantigen and anti-CD4 Ab
To determine whether the presence of both donor alloantigen and anti-CD4 Ab is required for the generation of a population of CD25+CD4+ regulatory T cells, we pretreated mice with either YTS177 only (days -28 and -27) or DST (day -27) only and transferred CD25+CD4+ T cells into MR mice.
CD25+CD4+ T cells (5
x 105) isolated after pretreatment with either
177 (only) or DST (only) were unable to regulate rejection mediated by
1 x 105
CD45RBhighCD4+ T cells
(MST = 20 and 20 days, respectively, p < 0.05,
177 alone or DST alone vs YTS177/DST-pretreated mice; Fig. 3).
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), demonstrating that in this
system, equivalent numbers of
CD25+CD4+ T cells from
naive animals are unable to regulate skin allograft rejection mediated
by CD45RBhigh effector cells. Taken together, the data clearly demonstrate that the generation of CD25+ cells with the capacity to regulate skin allograft rejection in this model depends on coexposure of recipient cells to alloantigen in the form of a DST and anti-CD4 Ab.
Pretreatment with the tolerizing YTS177/DST protocol: effect on expression of CD25 and CTLA-4
Having established that infusion of alloantigen in combination with the anti-CD4 mAb YTS177 generates CD25+CD4+ T cells that can regulate skin allograft rejection in a donor alloantigen-specific manner in vivo, we wished to determine whether CD4+ T cells from pretreated animals had particular phenotypic changes compared with CD4+ T cells from naive or control pretreated mice. Our initial attention focused on CD25, and we asked whether pretreated mice contained a higher proportion of CD25+CD4+ T cells or expressed CD25 at a higher level than control mice. Preliminary analysis showed only a very modest increase in the number of CD25+CD4+ T cells following pretreatment with the YTS177/DST tolerogenic protocol, but we speculated that significant changes might be more readily detected following re-exposure to alloantigen. Therefore, mice given the YTS177/DST pretreatment were rechallenged with the original tolerizing Ag in the form of a second DST at day 0 (normally the day of cell isolation and transfer in the adoptive transfer protocol) and were analyzed 2 days later by flow cytometry. When compared with CD4+ T cells from naive mice or control mice given DST only at day -27 and DST rechallenge at day 0, a higher proportion of CD4+ T cells from pretreated and rechallenged mice were positive for CD25 (15.8% compared with 10.01 and 11.1% in naive and and DST (only) controls, respectively). However, mice pretreated with YTS177 (only) at days -28 and -27 then rechallenged with donor Ag at day 0 also displayed an increase in the proportion of cells positive for CD25 (13.5%).
CTLA-4 is a CD28 homolog that has a negative regulatory role in T cell
activation (32, 33, 34) and has recently been shown to be
constitutively expressed on
CD4+CD25+ immunoregulatory
cells (19, 23, 35). Therefore, we examined the expression
of CTLA-4 by CD25+CD4+ T
cells in our system. Intracellular staining revealed that a greater
proportion of CD25+CD4+ T
cells from mice pretreated with the YTS177/DST protocol and re-exposed
to donor Ag were positive for CTLA-4 than were cells from either naive
or DST (only) control mice (45% compared with 32 and 36%,
respectively). However, control animals pretreated with YTS177 (only)
then re-exposed to alloantigen also showed a similar increase in the
proportion of CD25+CD4+ T
cells that were positive for CTLA-4 (42%). Therefore, at present we
are unable to conclude that the YTS177/DST-tolerizing protocol uniquely
leads to an increase in the proportion of cells that express either
CD25 or CTLA-4. However, we are aware that a limiting factor in this
system at present is that our phenotypic analysis is unable to
differentiate between alloantigen-specific
CD25+CD4+ T cells generated
by the YTS177/DST pretreatment and those "background"
CD25+CD4+ T cells that
occur spontaneously and, as shown in Fig. 3, are unable to regulate
rejection responses in this model. Experiments in progress, which
attempt to enrich for these Ag-specific cells, may shed further light
on their CD25 and CTLA-4 expression.
Induction of unresponsiveness leads to increased expression of CD122 by CD25+CD4+ T cells
In an attempt to characterize the regulatory population further,
we investigated the phenotype of cells isolated from
YTS177/DST-pretreated animals. CD25 is up-regulated as a consequence of
T cell activation, but, in view of the fact that in our system
CD25+CD4+ T cells clearly
regulate responses to alloantigens, we looked for other phenotypic
changes that might distinguish between activated and regulatory
populations. We chose to examine the expression of CD122 (the IL-2R
chain), and we speculated that reduced expression of this molecule
might allow CD25+CD4+
regulatory cells to compete for alloantigen or costimulatory molecules
without the ability to bind IL-2 with high affinity. As described
above, cells were isolated from YTS177/DST-pretreated animals
rechallenged with a second DST, and from naive mice and relevant
control animals. However, contrary to our hypothesis, flow cytometric
analysis revealed that CD122 was expressed by a greater proportion of
CD25+CD4+ T cells following
the induction of specific unresponsiveness and Ag rechallenge in vivo
(p 
0.002, YTS177/DST plus DST day 0 vs all
other groups, n = 4 each group; Fig. 4).
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CTLA-4 has been implicated in the mechanism of action of
CD25+CD4+ regulatory T
cells in autoimmune models (19, 23, 35). Therefore, we
sought to establish whether CTLA-4 was involved in the regulatory
activity of the CD25+CD4+ T
cells in our system. MR mice were reconstituted with 5 x
105
CD25+CD4+ T cells from
YTS177/DST-pretreated animals the day before receiving a skin graft.
Recipients received either anti-CTLA-4 mAb or control hamster IgG
at the time of cell transfer and weekly thereafter. Treatment continued
for 6 wk or until rejection was observed. Treatment with the control Ig
did not inhibit the regulatory activity of
CD25+CD4+ T cells from
YTS177/DST-pretreated mice, as animals receiving this treatment
accepted their skin grafts long term (n = 4, MST
> 100 days; Fig. 5). In contrast,
administration of anti-CTLA-4 Ab abrogated regulation, with six of
six mice rejecting their skin grafts acutely (MST = 17 days,
p < 0.01, CTLA-4 vs hamster Ig-treated mice; Fig. 5).
As an important control for this experiment, MR mice were given
anti-CTLA-4 Ab without coadministration of
CD25+CD4+ T cells. These
mice rejected their skins with the same tempo as MR mice without
anti-CTLA-4 Ab (MST = 17 days both groups; Fig. 5), showing
that blockade of CTLA-4 does not in itself enhance the ability of the
CD45RBhigh effector cells to mediate graft
rejection.
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In a number of experimental models in which immunoregulation is mediated by either CD45RBlow or CD25+CD4+ T cells, regulation has been shown to be dependent upon or at least involve IL-10 (14, 22, 36). Indeed, previous work from this laboratory using CD4+ T cells isolated from long-term tolerant mice that had accepted allografts for over 100 days demonstrated that regulation of skin graft rejection could be abrogated in 80% of mice by administration of a neutralizing IL-10 Ab (14). To assess the role of IL-10 in regulation in our system, MR mice were reconstituted with 5 x 105 CD25+CD4+ from YTS177/DST-preteated animals 1 day before skin grafting and at the time of cell transfer received either the IL-10R Ab 1B1.2 or isotype control Ab GL113.
Treatment with control Ab did not affect the regulatory activity of
CD25+CD4+ T cells from
pretreated mice, as all animals receiving this treatment accepted their
skin grafts long term (MST = 100, n = 4; Fig. 6). In clear contrast, blockade of the
IL-10 pathway abolished regulation with the majority of grafts rejected
by day 25 (MST = 22.5 days, n = 4; Fig. 6).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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CD25+CD4+ T cells purified
from YTS177/DST-pretreated animals were able to suppress skin graft
rejection mediated by
CD45RBhighCD4+ T cells in
five of six reconstituted recipients. Conversely, at equivalent cell
numbers, CD25-CD4+ T cells
from pretreated animals were unable to prevent rejection, demonstrating
that in this system the regulatory activity of the
CD4+ population was contained within the
CD25+ fraction (Fig. 2). This observation is in
accordance with our previous data demonstrating that
CD25-CD4+ T cells from
long-term tolerant animals do not possess regulatory activity
(14). In contrast, two recent studies have shown that
peripheral CD4+CD25- T
cells contain regulatory cells that prevent autoimmune disease
(36, 37). Analysis of CD4+
subpopulations has demonstrated that almost all
CD25+ cells are contained within the
CD45RBlow population (15), whereas
60% of CD45RBlow cells are
CD25- (36). In a variety of models,
CD45RBlow cells have been shown to regulate
immune pathology induced by CD45RBhigh cells.
Thus, the transfer of
CD25-CD4+ cells results
almost inevitably in the transfer of CD45RBlow
cells. Although we cannot rule out the possibility that at higher cell
numbers CD25- cells might mediate regulation in
our system, it is clear that at equivalent cell numbers
CD25- cells are ineffective in comparison with
their CD25+ counterparts.
In the current study, the regulatory populations were obtained from mice pretreated with the YTS177/DST pretreatment protocol. Given the fact that in autoimmune models (2, 15) and at least one transplantation model (38) regulatory cells could be obtained from naive animals, it was important to determine whether in our system alloantigen-specific regulatory cells could be found in naive animals. CD25+CD4+ T cells (5 x 105) isolated from naive mice were unable to regulate the rejection of skin allografts. This differs from models of autoimmune disease, such as the colitis model described by Read et al. (19) where CD25+CD4+ T cells from naive animals could effectively regulate the pathogenic effects of CD45RBhighCD4+ T cells and prevent disease. However, in such colitis models, T cells from naive animals would have had prior exposure to the relevant gut Ags, potentially driving the development or expansion of regulatory populations. The generation of regulatory cells from naive animals has also been demonstrated in a pancreas allograft model, where CD45RBlowCD4+ T cells from naive animals could regulate rejection mediated by CD45RBhighCD4+ T cells (38). The explanation for this difference seen between these data and ours is not apparent at present; however, in a previous study (14) we have also shown that CD45RBlowCD4+ T cells from naive animals were unable to regulate rejection. On balance, the data suggest that the generation of CD25+CD4+ regulatory T cells requires prior exposure to specific Ags. In the transplantation setting this may, for example, be in the form of a DST or cardiac allograft, whereas in autoimmune models such Ag would be naturally present in the body. It is almost certain that the precursor frequency of alloantigen-specific regulatory CD25+CD4+ T cells from naive animals is too low to allow regulation at the cell doses used and that our pretreatment regimen serves to increase this precursor frequency.
To determine whether the generation of alloantigen-specific regulatory
cells required the presence of both alloantigen and anti-CD4 Ab, we
pretreated with either Ab or DST alone and investigated whether
CD25+CD4+ T cells isolated
from these animals could display regulatory activity. Reconstitution of
MR mice with 5 x 105
CD25+CD4+ T cells isolated
from either DST alone- or YTS177 alone-pretreated mice resulted in
acute skin graft rejection (Fig. 3), supporting the view
(10) that for effective generation or expansion of these
regulatory cells the recipient immune system must encounter donor
alloantigen at the time of immunomodulation by anti-CD4
Ab.
To understand the effects of pretreatment on the
CD4+ populations isolated, we investigated the
phenotype of cells obtained from pretreated animals. Compared with
naive animals, YTS177/DST pretreatment and Ag rechallenge only modestly
increased the proportion of CD4+ T cells that
expressed CD25. This result is perhaps not unexpected, as T cell
activation as a consequence of exposure to Ag induces CD25 expression
(39). However, in our system, pretreatment with DST alone
at days -27 and 0 did not lead to a rise in the proportion of
CD4+ cells expressing CD25, suggesting that the
modest increase in the proportion of CD25+ cells
seen in the tolerizing protocol indicates more than simply "Ag
exposure." Administration of YTS177 (days -28 and -27) plus DST at
day 0 did lead to an increase in the proportion of
CD4+ T cells expressing CD25, but to a lesser
degree than after the combined YTS177/DST therapy. One potential
explanation for the slight increase in the proportion of CD4 cells
expressing CD25 in what were regarded as control animals in this study
is that when given alone at days -28 and -27, YTS177 does lead to
some prolongation of primary cardiac allograft survival in this strain
combination (MST = 20 days; Ref. 40 and A. R.
Bushell, unpublished data). However, as shown in Fig. 3, pretreatment
with YTS177 alone does not lead to regulation in this sensitive
adoptive transfer system, suggesting either that increase in CD25
expression is not an absolute indicator of regulation or that only the
combined pretreatment (YTS177/DST) sufficiently increases the precursor
frequency of alloantigen-specific regulatory cells. Experiments are in
progress that attempt to enumerate and isolate donor-specific cells
within the CD25+ population. From these
experiments, it might be possible to determine whether Ag-specific
regulatory cells require a certain threshold expression of CD25 to
exert their regulatory function.
In our system, as in many others, regulation is mediated by the
CD25-positive but not CD25-negative subset of
CD4+ T cells. CD25 is a key component of the
high-affinity IL-2R and, given that IL-2 is a critical cytokine in most
immune responses, we speculated that if CD25+
regulatory T cells were deficient in other components of the IL-2R they
might bind IL-2 with only low affinity and thereby act as abortive
competitors for alloantigen or for costimulatory or adhesion molecules
on APC. Therefore, our attention turned to CD122 (the IL-2R chain)
because this chain is largely responsible for IL-2 signal transduction
(41). In our system, we were surprised to find that a
greater proportion of
CD25+CD4+ cells obtained
from tolerized animals expressed CD122 compared with cells obtained
from control animals (Fig. 4). CD122 is used by the receptors of both
IL-2 and IL-15 (42), and it is possible that increased
expression of CD122 by regulatory cells could allow higher affinity
binding of IL-2, IL-15, or both. Preferential binding of IL-2 may
reduce the availability of this cytokine to effector cells, thus
reducing their expansion. IL-15 has been shown to reduce the
susceptibility of T cells to activation-induced cell death
(43). Therefore, increased expression of CD122 may provide
regulatory cells with a survival advantage, allowing immune regulation
to persist. Given our data regarding CD122 expression, it is
interesting to note that CD122 has recently been shown to be
constitutively expressed on ex vivo isolated human regulatory
CD25+CD4+ T cells
(44, 45).
CTLA-4, a CD28 homolog, is expressed on T cells after activation and
has been shown to down-regulate T cell responses (32, 34, 46, 47). Evidence for a critical role of CTLA-4 is provided by the
observation that, in vivo, CTLA-4-deficient mice develop a
lymphoproliferative disorder resulting from uncontrolled expansion of
CD4+ T cells and die within 3–4 wk
(47). As recent studies have shown that immunoregulatory
CD25+CD4+ T cells express
CTLA-4 (19, 23, 35), we wished to investigate its
expression in our system. Although when compared with naive mice
CD25+ cells from YTS177/DST-pretreated animals
showed an increased intracellular content of CTLA-4, a similar increase
was also seen in control animals pretreated with YTS177 alone. Thus, in
this model, where probably only a small proportion of
CD25+ T cells are specific for donor
alloantigens, we are unable to conclude that an increased CTLA-4
content/expression correlates with the ability of
CD25+CD4+ T cells to
mediate donor alloantigen-specific regulation. However, when CTLA-4 was
targeted in vivo, the results were unequivocal. As shown in Fig. 5, administration of anti-CTLA-4 Ab completely abolished regulation
mediated by CD25+CD4+ T
cells isolated from YTS177/DST-pretreated animals, providing clear
evidence for a role for CTLA-4 in this as in other systems. Thus,
although we were unable to detect a specific increase in CTLA-4
expression following pretreatment with the tolerizing protocol using
phenotypic analysis, the in vivo data clearly implicate CTLA-4 as an
important factor in the regulation mediated by
CD25+CD4+ T cells in this
model.
Various outcomes have been identified following cross-linking of CTLA-4
in vitro. These include recruitment of the phosphatase SHP-2
into the immunological synapse (48, 49) and the secretion
of the immunoregulatory cytokine TGF- (50). TGF-
blockade has been shown to abrogate regulation by
CD25+CD4+ T cells in an
autoimmune model (19).
IL-10 has been shown to display a range of immune suppressive effects, including inhibition of APC function (51), induction of anergy (52), differentiation of regulatory (Tr1) T cells in vitro (4), and control of the expansion of other T cell populations (53). We had previously identified IL-10 as a key factor in the regulation of skin graft rejection mediated by CD45RBlowCD4+ T cells obtained from long-term tolerant mice (14); thus, we asked whether IL-10 also played a critical regulatory role in the adoptive transfer system using CD25+CD4+ T cells from pretreated-only mice. Blockade of the IL-10 pathway using an anti-IL-10R Ab abolished the ability of CD25+CD4+ T cells to regulate skin graft rejection mediated by naive CD45RBhighCD4+ T cells.
How IL-10 exerts its immune suppressive effects in our system is at
present unknown. However, recent data from Cottrez (54)
has demonstrated a link between IL-10 and TGF-, with IL-10 enhancing
the expression of TGF-R expression on activated and resting T cells.
As cross-linking of CTLA-4 has been shown to induce the production
TGF- (50), we can speculate that there may be a common
mechanism of action linking CTLA-4 and IL-10.
To our knowledge, this is the first demonstration that alloantigen-specific CD25+ regulatory cells can be generated following manipulation of the adult immune system. We believe that an understanding of the way in which these cells develop could have implications for the treatment of autoimmune disease as well as in the field of tolerance induction in transplantation. The fact that in this system regulation is dependent on CTLA-4 and IL-10 provides evidence for common mechanisms between recently generated and naturally occurring regulatory T cells.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Andrew Bushell, Nuffield Department of Surgery, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, U.K. E-mail address: Andrew.Bushell{at}nds.ox.ac.uk
3 Abbreviations used in this paper: DST, donor-specific transfusion; MST, median survival time; MR, minimally reconstituted.
Received for publication August 8, 2001. Accepted for publication November 16, 2001.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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and interleukin 4 in the prevention of autoimmune thyroiditis in rats by peripheral CD4+CD45RC- cells and CD4+CD8- thymocytes. J. Exp. Med. 189:279.
in long-surviving mouse heart allografts after brief CD4-monoclonal antibody therapy. Transplantation 59:559.[Medline]
chains (CD25). J. Immunol. 155:1151.[Abstract]
,25-dihydroxyvitamin D3 and mycophenolate mofetil treatment mediate transplantation tolerance. J. Immunol. 167:1945. (TGF-) production by murine CD4+ T cells. J. Exp. Med. 188:1849. response during T cell activation is modulated IL-10. J. Immunol. 167:773.This article has been cited by other articles:
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|
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|
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|
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|
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|
|
|
|
|
|
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|
|
|
|
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|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
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|
|
 |
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|
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|
 |
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|
|
|
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|
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|
|
|
|
|
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|
|
|
|
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|
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|
|
 |
|
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|
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|
|
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|
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|
|
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|
|
|
|
 |
|
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|
|
|
|
 |
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
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|
|
|
|
 |
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
 |
|
 T. Mutis, R. S. van Rijn, E. R. Simonetti, T. Aarts-Riemens, M. E. Emmelot, L. van Bloois, A. Martens, L. F. Verdonck, and S. B. Ebeling Human Regulatory T Cells Control Xenogeneic Graft-versus-Host Disease Induced by Autologous T Cells in RAG2-/-{gamma}c-/- Immunodeficient Mice. Clin. Cancer Res., September 15, 2006; 12(18): 5520 - 5525. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Wang, Y. Liu, J. Wang, G. Ding, W. Zhang, G. Chen, M. Zhang, S. Zheng, and X. Cao Induction of Allospecific Tolerance by Immature Dendritic Cells Genetically Modified to Express Soluble TNF Receptor J. Immunol., August 15, 2006; 177(4): 2175 - 2185. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Xu, J. Fu, L. Jin, H. Zhang, C. Zhou, Z. Zou, J.-M. Zhao, B. Zhang, M. Shi, X. Ding, et al. Circulating and Liver Resident CD4+CD25+ Regulatory T Cells Actively Influence the Antiviral Immune Response and Disease Progression in Patients with Hepatitis B J. Immunol., July 1, 2006; 177(1): 739 - 747. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Fandrich Induction of tolerance in clinical organ transplantation Nephrol. Dial. Transplant., May 1, 2006; 21(5): 1170 - 1173. [Full Text] [PDF]
|
|
|
|
|
|
J. J. A. Coenen, H. J. P. M. Koenen, E. van Rijssen, L. Boon, I. Joosten, and L. B. Hilbrands CTLA-4 Engagement and Regulatory CD4+CD25+ T Cells Independently Control CD8+-Mediated Responses under Costimulation Blockade J. Immunol., May 1, 2006; 176(9): 5240 - 5246. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. C. Neujahr, C. Chen, X. Huang, J. F. Markmann, S. Cobbold, H. Waldmann, M. H. Sayegh, W. W. Hancock, and L. A. Turka Accelerated Memory Cell Homeostasis during T Cell Depletion and Approaches to Overcome It. J. Immunol., April 15, 2006; 176(8): 4632 - 4639. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. Barao, A. M. Hanash, W. Hallett, L. A. Welniak, K. Sun, D. Redelman, B. R. Blazar, R. B. Levy, and W. J. Murphy Suppression of natural killer cell-mediated bone marrow cell rejection by CD4+CD25+ regulatory T cells PNAS, April 4, 2006; 103(14): 5460 - 5465. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Chen, N. Zhang, S. Fu, B. Schroppel, Q. Guo, A. Garin, S. A. Lira, and J. S. Bromberg CD4+CD25+ Regulatory T-Cells Inhibit the Islet Innate Immune Response and Promote Islet Engraftment. Diabetes, April 1, 2006; 55(4): 1011 - 1021. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Deng, D. J. Moore, X. Huang, M. Mohiuddin, M. K. Lee IV, E. Velidedeoglu, M.-M. Lian, M. Chiaccio, S. Sonawane, A. Orlin, et al. Antibody-induced transplantation tolerance that is dependent on thymus-derived regulatory T cells. J. Immunol., March 1, 2006; 176(5): 2799 - 2807. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Rieger, C. Loddenkemper, J. Maul, T. Fietz, D. Wolff, H. Terpe, B. Steiner, E. Berg, S. Miehlke, M. Bornhauser, et al. Mucosal FOXP3+ regulatory T cells are numerically deficient in acute and chronic GvHD Blood, February 15, 2006; 107(4): 1717 - 1723. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. A. Coenen, H. J. P. M. Koenen, E. van Rijssen, L. B. Hilbrands, and I. Joosten Rapamycin, and not cyclosporin A, preserves the highly suppressive CD27+ subset of human CD4+CD25+ regulatory T cells Blood, February 1, 2006; 107(3): 1018 - 1023. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Sanchez-Fueyo, S. Sandner, A. Habicht, C. Mariat, J. Kenny, N. Degauque, X. X. Zheng, T. B. Strom, L. A. Turka, and M. H. Sayegh Specificity of CD4+CD25+ Regulatory T Cell Function in Alloimmunity J. Immunol., January 1, 2006; 176(1): 329 - 334. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. A. Wysocki, Q. Jiang, A. Panoskaltsis-Mortari, P. A. Taylor, K. P. McKinnon, L. Su, B. R. Blazar, and J. S. Serody Critical role for CCR5 in the function of donor CD4+CD25+ regulatory T cells during acute graft-versus-host disease Blood, November 1, 2005; 106(9): 3300 - 3307. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. P Cobbold T cell tolerance induced by therapeutic antibodies Phil Trans R Soc B, September 29, 2005; 360(1461): 1695 - 1705. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Chen, D. Zhou, J. R. Torrealba, T. K. Waddell, D. Grant, and L. Zhang Donor Lymphocyte Infusion Induces Long-Term Donor-Specific Cardiac Xenograft Survival through Activation of Recipient Double-Negative Regulatory T Cells J. Immunol., September 1, 2005; 175(5): 3409 - 3416. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Domenig, A. Sanchez-Fueyo, J. Kurtz, S. P. Alexopoulos, C. Mariat, M. Sykes, T. B. Strom, and X. X. Zheng Roles of Deletion and Regulation in Creating Mixed Chimerism and Allograft Tolerance Using a Nonlymphoablative Irradiation-Free Protocol J. Immunol., July 1, 2005; 175(1): 51 - 60. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Sawitzki, C. I. Kingsley, V. Oliveira, M. Karim, M. Herber, and K. J. Wood IFN-{gamma} production by alloantigen-reactive regulatory T cells is important for their regulatory function in vivo J. Exp. Med., June 20, 2005; 201(12): 1925 - 1935. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. J. P. M. Koenen, E. Fasse, and I. Joosten CD27/CFSE-Based Ex Vivo Selection of Highly Suppressive Alloantigen-Specific Human Regulatory T Cells J. Immunol., June 15, 2005; 174(12): 7573 - 7583. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Karim, G. Feng, K. J. Wood, and A. R. Bushell CD25+CD4+ regulatory T cells generated by exposure to a model protein antigen prevent allograft rejection: antigen-specific reactivation in vivo is critical for bystander regulation Blood, June 15, 2005; 105(12): 4871 - 4877. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Gangi, C. Vasu, D. Cheatem, and B. S. Prabhakar IL-10-Producing CD4+CD25+ Regulatory T Cells Play a Critical Role in Granulocyte-Macrophage Colony-Stimulating Factor-Induced Suppression of Experimental Autoimmune Thyroiditis J. Immunol., June 1, 2005; 174(11): 7006 - 7013. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Kojima, Y. Kanno, H. Hase, and T. Kobata CD4+CD25+ Regulatory T Cells Attenuate the Phosphatidylinositol 3-Kinase/Akt Pathway in Antigen-Primed Immature CD8+ CTLs during Functional Maturation J. Immunol., May 15, 2005; 174(10): 5959 - 5967. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. W. Nasr, Y. Wang, G. Gao, S. Deng, L. Diggs, D. M. Rothstein, G. Tellides, F. G. Lakkis, and Z. Dai Testicular Immune Privilege Promotes Transplantation Tolerance by Altering the Balance between Memory and Regulatory T Cells J. Immunol., May 15, 2005; 174(10): 6161 - 6168. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Bushell, E. Jones, A. Gallimore, and K. Wood The Generation of CD25+CD4+ Regulatory T Cells That Prevent Allograft Rejection Does Not Compromise Immunity to a Viral Pathogen J. Immunol., March 15, 2005; 174(6): 3290 - 3297. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Schenk, D. D. Kish, C. He, T. El-Sawy, E. Chiffoleau, C. Chen, Z. Wu, S. Sandner, A. V. Gorbachev, K. Fukamachi, et al. Alloreactive T Cell Responses and Acute Rejection of Single Class II MHC-Disparate Heart Allografts Are under Strict Regulation by CD4+CD25+ T Cells J. Immunol., March 15, 2005; 174(6): 3741 - 3748. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. C. Zenclussen, K. Gerlof, M. L. Zenclussen, A. Sollwedel, A. Z. Bertoja, T. Ritter, K. Kotsch, J. Leber, and H.-D. Volk Abnormal T-Cell Reactivity against Paternal Antigens in Spontaneous Abortion: Adoptive Transfer of Pregnancy-Induced CD4+CD25+ T Regulatory Cells Prevents Fetal Rejection in a Murine Abortion Model Am. J. Pathol., March 1, 2005; 166(3): 811 - 822. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C Veltkamp, R B Sartor, T Giese, F Autschbach, I Kaden, R Veltkamp, D Rost, B Kallinowski, and W Stremmel Regulatory CD4+CD25+ cells reverse imbalances in the T cell pool of bone marrow transplanted TG{varepsilon}26 mice leading to the prevention of colitis Gut, February 1, 2005; 54(2): 207 - 214. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
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|
|
|
|
|
|
P. A. Taylor, A. Panoskaltsis-Mortari, J. M. Swedin, P. J. Lucas, R. E. Gress, B. L. Levine, C. H. June, J. S. Serody, and B. R. Blazar L-Selectinhi but not the L-selectinlo CD4+25+ T-regulatory cells are potent inhibitors of GVHD and BM graft rejection Blood, December 1, 2004; 104(12): 3804 - 3812. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
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|
|
|
|
|
|
A. E. Foster, M. Marangolo, M. M. Sartor, S. I. Alexander, M. Hu, K. F. Bradstock, and D. J. Gottlieb Human CD62L- memory T cells are less responsive to alloantigen stimulation than CD62L+ naive T cells: potential for adoptive immunotherapy and allodepletion Blood, October 15, 2004; 104(8): 2403 - 2409. [Abstract] [Full Text] [PDF]
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B. E. Anderson, J. M. McNiff, C. Matte, I. Athanasiadis, W. D. Shlomchik, and M. J. Shlomchik Recipient CD4+ T cells that survive irradiation regulate chronic graft-versus-host disease Blood, September 1, 2004; 104(5): 1565 - 1573. [Abstract] [Full Text] [PDF]
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A. L. Kinter, M. Hennessey, A. Bell, S. Kern, Y. Lin, M. Daucher, M. Planta, M. McGlaughlin, R. Jackson, S. F. Ziegler, et al. CD25+CD4+ Regulatory T Cells from the Peripheral Blood of Asymptomatic HIV-infected Individuals Regulate CD4+ and CD8+ HIV-specific T Cell Immune Responses In Vitro and Are Associated with Favorable Clinical Markers of Disease Status J. Exp. Med., August 2, 2004; 200(3): 331 - 343. [Abstract] [Full Text] [PDF]
|
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E. Nishimura, T. Sakihama, R. Setoguchi, K. Tanaka, and S. Sakaguchi Induction of antigen-specific immunologic tolerance by in vivo and in vitro antigen-specific expansion of naturally arising Foxp3+CD25+CD4+ regulatory T cells Int. Immunol., August 1, 2004; 16(8): 1189 - 1201. [Abstract] [Full Text] [PDF]
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P. Hoffmann, R. Eder, L. A. Kunz-Schughart, R. Andreesen, and M. Edinger Large-scale in vitro expansion of polyclonal human CD4+CD25high regulatory T cells Blood, August 1, 2004; 104(3): 895 - 903. [Abstract] [Full Text] [PDF]
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L. Graca, A. Le Moine, C.-Y. Lin, P. J. Fairchild, S. P. Cobbold, and H. Waldmann Donor-specific transplantation tolerance: The paradoxical behavior of CD4+CD25+ T cells PNAS, July 6, 2004; 101(27): 10122 - 10126. [Abstract] [Full Text] [PDF]
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Q. Tang, K. J. Henriksen, M. Bi, E. B. Finger, G. Szot, J. Ye, E. L. Masteller, H. McDevitt, M. Bonyhadi, and J. A. Bluestone In Vitro-expanded Antigen-specific Regulatory T Cells Suppress Autoimmune Diabetes J. Exp. Med., June 7, 2004; 199(11): 1455 - 1465. [Abstract] [Full Text] [PDF]
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 T. L. Sumpter and D. S. Wilkes Role of autoimmunity in organ allograft rejection: a focus on immunity to type V collagen in the pathogenesis of lung transplant rejection Am J Physiol Lung Cell Mol Physiol, June 1, 2004; 286(6): L1129 - L1139. [Abstract] [Full Text] [PDF]
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M. K. Lee IV, D. J. Moore, B. P. Jarrett, M. M. Lian, S. Deng, X. Huang, J. W. Markmann, M. Chiaccio, C. F. Barker, A. J. Caton, et al. Promotion of Allograft Survival by CD4+CD25+ Regulatory T Cells: Evidence for In Vivo Inhibition of Effector Cell Proliferation J. Immunol., June 1, 2004; 172(11): 6539 - 6544. [Abstract] [Full Text] [PDF]
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O. Joffre, N. Gorsse, P. Romagnoli, D. Hudrisier, and J. P. M. van Meerwijk Induction of antigen-specific tolerance to bone marrow allografts with CD4+CD25+ T lymphocytes Blood, June 1, 2004; 103(11): 4216 - 4221. [Abstract] [Full Text] [PDF]
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J. Kurtz, J. Shaffer, A. Lie, N. Anosova, G. Benichou, and M. Sykes Mechanisms of early peripheral CD4 T-cell tolerance induction by anti-CD154 monoclonal antibody and allogeneic bone marrow transplantation: evidence for anergy and deletion but not regulatory cells Blood, June 1, 2004; 103(11): 4336 - 4343. [Abstract] [Full Text] [PDF]
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P. L. Vieira, J. R. Christensen, S. Minaee, E. J. O'Neill, F. J. Barrat, A. Boonstra, T. Barthlott, B. Stockinger, D. C. Wraith, and A. O'Garra IL-10-Secreting Regulatory T Cells Do Not Express Foxp3 but Have Comparable Regulatory Function to Naturally Occurring CD4+CD25+ Regulatory T Cells J. Immunol., May 15, 2004; 172(10): 5986 - 5993. [Abstract] [Full Text] [PDF]
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S. P. Cobbold, R. Castejon, E. Adams, D. Zelenika, L. Graca, S. Humm, and H. Waldmann Induction of foxP3+ Regulatory T Cells in the Periphery of T Cell Receptor Transgenic Mice Tolerized to Transplants J. Immunol., May 15, 2004; 172(10): 6003 - 6010. [Abstract] [Full Text] [PDF]
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B. K. Choi, J. S. Bae, E. M. Choi, W. J. Kang, S. Sakaguchi, D. S. Vinay, and B. S. Kwon 4-1BB-dependent inhibition of immunosuppression by activated CD4+CD25+ T cells J. Leukoc. Biol., May 1, 2004; 75(5): 785 - 791. [Abstract] [Full Text] [PDF]
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E. M. Aandahl, J. Michaelsson, W. J. Moretto, F. M. Hecht, and D. F. Nixon Human CD4+ CD25+ Regulatory T Cells Control T-Cell Responses to Human Immunodeficiency Virus and Cytomegalovirus Antigens J. Virol., March 1, 2004; 78(5): 2454 - 2459. [Abstract] [Full Text] [PDF]
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Y. Zheng, C. N. Manzotti, M. Liu, F. Burke, K. I. Mead, and D. M. Sansom CD86 and CD80 Differentially Modulate the Suppressive Function of Human Regulatory T Cells J. Immunol., March 1, 2004; 172(5): 2778 - 2784. [Abstract] [Full Text] [PDF]
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K. T. Nouri-Aria, P. A. Wachholz, J. N. Francis, M. R. Jacobson, S. M. Walker, L. K. Wilcock, S. Q. Staple, R. C. Aalberse, S. J. Till, and S. R. Durham Grass Pollen Immunotherapy Induces Mucosal and Peripheral IL-10 Responses and Blocking IgG Activity J. Immunol., March 1, 2004; 172(5): 3252 - 3259. [Abstract] [Full Text] [PDF]
|
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A. van Maurik, B. F. de St. Groth, K. J. Wood, and N. D. Jones Dependency of Direct Pathway CD4+ T Cells on CD40-CD154 Costimulation Is Determined by Nature and Microenvironment of Primary Contact with Alloantigen J. Immunol., February 15, 2004; 172(4): 2163 - 2170. [Abstract] [Full Text] [PDF]
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X. Zhang, D. N. Koldzic, L. Izikson, J. Reddy, R. F. Nazareno, S. Sakaguchi, V. K. Kuchroo, and H. L. Weiner IL-10 is involved in the suppression of experimental autoimmune encephalomyelitis by CD25+CD4+ regulatory T cells Int. Immunol., February 1, 2004; 16(2): 249 - 256. [Abstract] [Full Text] [PDF]
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S. G. Zheng, J. H. Wang, M. N. Koss, F. Quismorio Jr., J. D. Gray, and D. A. Horwitz CD4+ and CD8+ Regulatory T Cells Generated Ex Vivo with IL-2 and TGF-{beta} Suppress a Stimulatory Graft-versus-Host Disease with a Lupus-Like Syndrome J. Immunol., February 1, 2004; 172(3): 1531 - 1539. [Abstract] [Full Text] [PDF]
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M. Karim, C. I. Kingsley, A. R. Bushell, B. S. Sawitzki, and K. J. Wood Alloantigen-Induced CD25+CD4+ Regulatory T Cells Can Develop In Vivo from CD25-CD4+ Precursors in a Thymus-Independent Process J. Immunol., January 15, 2004; 172(2): 923 - 928. [Abstract] [Full Text] [PDF]
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H. J. P. M. Koenen, E. Fasse, and I. Joosten IL-15 and Cognate Antigen Successfully Expand De Novo-Induced Human Antigen-Specific Regulatory CD4+ T Cells That Require Antigen-Specific Activation for Suppression J. Immunol., December 15, 2003; 171(12): 6431 - 6441. [Abstract] [Full Text] [PDF]
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V. V. Jain, T. R. Businga, K. Kitagaki, C. L. George, P. T. O'Shaughnessy, and J. N. Kline Mucosal immunotherapy with CpG oligodeoxynucleotides reverses a murine model of chronic asthma induced by repeated antigen exposure Am J Physiol Lung Cell Mol Physiol, November 1, 2003; 285(5): L1137 - L1146. [Abstract] [Full Text] [PDF]
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P. Feunou, L. Poulin, C. Habran, A. Le Moine, M. Goldman, and M. Y. Braun CD4+CD25+ and CD4+CD25- T Cells Act Respectively as Inducer and Effector T Suppressor Cells in Superantigen-Induced Tolerance J. Immunol., October 1, 2003; 171(7): 3475 - 3484. [Abstract] [Full Text] [PDF]
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T. Mizobuchi, K. Yasufuku, Y. Zheng, M. A. Haque, K. M. Heidler, K. Woods, G. N. Smith Jr., O. W. Cummings, T. Fujisawa, J. S. Blum, et al. Differential Expression of Smad7 Transcripts Identifies the CD4+CD45RChigh Regulatory T Cells That Mediate Type V Collagen-Induced Tolerance to Lung Allografts J. Immunol., August 1, 2003; 171(3): 1140 - 1147. [Abstract] [Full Text] [PDF]
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 A. D. Salama, N. Najafian, M. R. Clarkson, W. E. Harmon, and M. H. Sayegh Regulatory CD25+ T Cells in Human Kidney Transplant Recipients J. Am. Soc. Nephrol., June 1, 2003; 14(6): 1643 - 1651. [Abstract] [Full Text] [PDF]
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W. Chen, M. S. Ford, K. J. Young, M. I. Cybulsky, and L. Zhang Role of Double-Negative Regulatory T Cells in Long-Term Cardiac Xenograft Survival J. Immunol., February 15, 2003; 170(4): 1846 - 1853. [Abstract] [Full Text] [PDF]
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;
n = 8, MST = 22.5). Cotransfer of 5 x
105 CD25+CD4+ T cells isolated from
YTS177/DST-pretreated CBA mice prevented rejection of B10 skin grafts
(
; n = 8, MST > 100 days), whereas 5
x 105 CD25-CD4+ T cells from
YTS177/DST-pretreated CBA mice were unable to prevent rejection (
;
n = 4, MST = 10 days). Cotransfer of
CD25+CD4+ T cells isolated from CBA mice
pretreated with BALB/c blood under the cover of YTS177 (third-party
control; •; n = 5, MST = 19 days) did not
prevent rejection of B10 skin grafts.
; n = 8, MST = 22.5).
Cotransfer of 5 x 105
CD25+CD4+ T cells isolated from
YTS177/DST-pretreated CBA mice prevented rejection of B10 skin grafts
(
; n = 5, MST = 20 days) or
isolated from naive CBA mice (
; n = 6, MST
= 20 days) did not prevent rejection of skin grafts.
