The JI
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     
 

The Journal of Immunology, 2008, 180, 2747-2751
Copyright © 2008 by The American Association of Immunologists, Inc.
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by van Mierlo, G. J. D.
Right arrow Articles by Toes, R. E. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by van Mierlo, G. J. D.
Right arrow Articles by Toes, R. E. M.

Cutting Edge: TNFR-Shedding by CD4+CD25+ Regulatory T Cells Inhibits the Induction of Inflammatory Mediators1

Geertje J. D. van Mierlo2,*, Hans U. Scherer2,*, Marjolijn Hameetman2,*, Mary E. Morgan*, Roelof Flierman*,{dagger}, Tom W. J. Huizinga* and René E. M. Toes3,*

* Department of Rheumatology and {dagger} Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results and Discussion
 Disclosures
 References
 
CD4+CD25+ regulatory T (Treg) cells play an essential role in maintaining tolerance to self and nonself. In several models of T cell-mediated (auto) immunity, Treg cells exert protective effects by the inhibition of pathogenic T cell responses. In addition, Treg cells can modulate T cell-independent inflammation. We now show that CD4+CD25+ Treg cells are able to shed large amounts of TNFRII. This is paralleled by their ability to inhibit the action of TNF-{alpha} both in vitro and in vivo. In vivo, Treg cells suppressed IL-6 production in response to LPS injection in mice. In contrast, Treg cells from TNFRII-deficient mice were unable to do so despite their unhampered capacity to suppress T cell proliferation in a conventional in vitro suppression assay. Thus, shedding of TNFRII represents a novel mechanism by which Treg cells can inhibit the action of TNF, a pivotal cytokine driving inflammation.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results and Discussion
 Disclosures
 References
 
Current understanding of the basic processes that control immune tolerance has been fueled by identification of CD4+CD25+ regulatory T (Treg)4 cells as an important component of self-tolerance. CD4+CD25+ T cells have been shown to regulate peripheral self-tolerance, protect against autoimmunity, and suppress immune responses to autoantigens, alloantigens, tumor Ags, and infectious agents (1, 2, 3, 4).

Despite accumulating evidence for the immunoregulatory properties of CD4+CD25+ Treg cells, the mechanism by which CD4+CD25+ Treg cells inhibit T cell-independent inflammation is not well defined. CD4+CD25+ Treg cells are anergic to TCR stimulation in vitro and capable of inhibiting proliferation and cytokine production of other T cells by secretion of anti-inflammatory cytokines (e.g., IL-10 and TGF-β) and a mechanism that depends on CTLA-4 and membrane-bound TGF-β (5, 6).

We previously showed that adoptive transfer of Treg cells decreases levels of acute phase proteins such as the serum amyloid P component in mice that had been injected with CFA (our unpublished observations) or had underwent total body irradiation (7). For that reason, we hypothesized that Treg cells shed a soluble mediator that can inhibit the induction of acute phase responses. TNF-{alpha} is one of the most prominent initiators of the acute phase reaction that can, via the action of IL-6, promote the release of several acute phase proteins from the liver (8, 9, 10). In this study, we describe a novel mechanism by which Treg cells can counteract the action mediated by TNF-{alpha}.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results and Discussion
 Disclosures
 References
 
Mice

C57BL/6 mice and TNFRII knockout (KO) mice on a C57BL/6 background (B6.129S2-Tnfrsf1btm1Mwm/J) were maintained at Leiden University Medical Center animal facility in accordance with national legislation under the supervision of the University’s animal experimental committee.

Isolation of murine Treg cells and culture

Murine CD4+CD25+ and CD4+CD25– T cells were isolated from spleen and lymph nodes of 6- to 14-wk-old mice by positive selection of CD4+ T cells (MACS), fluorescent labeling (anti-CD4 anti-CD25), and subsequent FACS sorting (FACSAria cell sorter; BD Biosciences) on the basis of CD25 expression. Purified T cell subsets were activated in the presence of Dynabeads mouse CD3/CD28 (Dynal Biotech) and 50 IU/ml IL-2.

Isolation of human Treg cells and culture

Isolation of human CD4+CD25high or CD4+CD25– T cells from buffy coats of healthy human donors was performed as previously described (11). FACS-sorted CD4+CD25high and CD4+CD25– cells were cultured in the presence of 1 µg/ml anti-CD28 (CLB-CD28/1; Sanquin), 5 µg/ml plate-bound anti-CD3 (OKT-3, BD Biosciences), and 100 U/ml IL-2 for up to 5 days. The metalloproteinase inhibitor marimastat was added to cultures where indicated at a final concentration of 10 µg/ml.

Suppression assay

After 3 to 4 days of in vitro activation, CD4+CD25– and CD4+CD25+ T cells were cultured with equal numbers of freshly isolated splenocytes in the presence of 1 µg/ml PHA. [3H]Thymidine incorporation of triplicates was measured 3–4 days later. Suppression assays were performed for each sorted population of CD4+CD25+ cells to ensure the suppressive capacity of isolated Treg cells.

Flow cytometry

Murine cells were stained using mAb against CD4, CD25, CD120b (TR75-89), FoxP3 (FJK-16S, eBioscience), or an isotype control. Human cells were stained using mAb against CD4 (RPA-T4), CD25 (2A3), CD120b (MR2-1, AbD Serotec and 22235, R&D Systems), CCR7 (3D12), HLA-DR (L243), CD45RO (UCHL1), CD45RA (HI100), and CD62L (Dreg 56). Intracellular FoxP3-staining was performed using eBioscience FoxP3-staining kit (PCH101 or appropriate isotype control). Abs were purchased from BD Biosciences unless otherwise stated.

TNFRI and TNFRII secretion

Souble TNFR (sTNFR) I and sTNFRII in culture supernatants were measured using standard ELISA kits (Hycult Biotechnology for murine sTNFR and R&D Systems DuoSet for human sTNFR).

Bioactivity of sTNFR

In vitro activity of sTNFR was measured using TNF-{alpha}-sensitive WEHI 164 clone 13 cells as previously described (12). In vivo activity was determined by injecting mice i.v. with 1 x 106 Treg or control cells (CD4+CD25– T cells) of either wild-type (WT) animals or TNFRII KO animals after 4 days of in vitro activation. As a control, mice were injected i.v. with 250 µg of etanercept, a TNFRII-Ig fusion protein. One hour later mice were injected i.p. with 150 µg of LPS (Salmonella typhosa, Sigma-Aldrich). Four and 6 h after LPS injection, blood samples were collected to determine serum levels of IL-6 using BD Biosciences mouse IL-6 ELISA set.


   Results and Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results and Discussion
Disclosures
 References
 
Shedding of sTNFRII by murine CD4+CD25+ Treg cells but not by CD4+CD25– cells

Adoptive transfer of CD4+CD25+ Treg cells can inhibit the induction of acute phase responses in mice (7). Because TNF-{alpha} stimulates acute phase responses (8, 9, 10), we hypothesized that CD4+CD25+ Treg cells could directly inhibit TNF-{alpha}. FACS analysis revealed that CD4+CD25+ Treg cells, as opposed to CD4+CD25– T cells, strongly express TNFRII (data not shown), leading us to predict that Treg cells may be able to shed sTNFRII. Therefore, we activated purified CD4+CD25+ and CD4+CD25– T cell populations in vitro and analyzed supernatants of these cultures for the presence of sTNFR. Although no sTNFRI could be observed (data not shown), sTNFRII was detectable in culture supernatants of CD25+ cells from day 1 onward (Fig. 1). No TNFR shedding was noted in the presence of IL-2 only (data not shown), indicating that TCR triggering is required for TNFR shedding.


Figure 1
View larger version (14K):
[in this window]
[in a new window]

  		FIGURE 1. CD4+CD25+ T cells shed TNFRII. Levels of soluble TNFRII in cell culture supernatants are shown. CD4+CD25+ and CD4+CD25– cells were cultured with anti-CD3/anti-CD28 coated beads and IL-2. Supernatant was analyzed for the presence of TNFRII by ELISA (*, p < 0.05; **, p = 0.0001). Depicted is one representative experiment of three.

 
Although sTNFR were also detected in the cultures of activated CD4+CD25– cells, this T cell subset produced far fewer sTNFR. CD4+CD25– T cells proliferate more vigorously than CD4+CD25+ Treg cell populations, resulting in 8–10 times higher cell numbers after 6 days of culture. When corrected for cell numbers, CD4+CD25+ Treg cells produced ~50 times more sTNFR than their CD4+CD25– counterparts on a per cell basis (data not shown).

CD4+CD25+ Treg cell-derived sTNFRII inhibits the action of TNF-{alpha} in vitro

We next wished to examine the biologic activity of Treg cell-derived sTNFRII. For this purpose we performed a bioassay using TNF-{alpha}-sensitive WEHI cells (12). Survival of WEHI cells was measured after incubation with ranging amounts of rTNF-{alpha} in the presence or absence of culture supernatants derived from activated CD4+CD25+ and CD4+CD25– T cells. Supernatant from CD4+CD25– T cells induced ~50% WEHI cell death without the addition of rTNF-{alpha}, reflecting increased shedding of TNF-{alpha} by activated CD25– effector T (Teff) cells as compared with CD4+CD25+ Treg cells. TNF-{alpha} -induced death of WEHI cells was largely prevented, however, when, next to titrated amounts of recombinant TNF-{alpha}, culture supernatant of CD4+CD25+ Treg cells was added to the wells. (Fig. 2A). To confirm that the inhibition of cell death was indeed mediated by sTNFRII, we next isolated CD4+CD25+ Treg cells from TNFRII KO mice. No inhibition of cell death was observed after the addition of culture supernatants from activated CD4+CD25+ cells derived from TNFRII KO mice (Fig. 2B). Nonetheless, these cells were at least as potent as CD4+CD25+ cells from control WT animals in a conventional in vitro T cell suppression assay, indicating that CD4+CD25+ cells from TNFRII KO animals were bona fide Treg cells with the ability to suppress Teff cells (Fig. 2C). Addition of etanercept, a soluble TNFRII-Ig fusion protein used clinically to treat rheumatoid arthritis, had comparable effects on the survival of WEHI cells (Fig. 2B). These data indicate that the ability of Treg cells to inhibit T cell proliferation is unaffected in TNFRII KO mice and further show that Treg cell-derived sTNFRII is functional because it is able to prevent the action of TNF-{alpha} in vitro.


Figure 2
View larger version (22K):
[in this window]
[in a new window]

  		FIGURE 2. Biological activity of Treg cell-derived sTNFRII. A, sTNFRII in the supernatant of CD4+CD25+ T cell cultures can prevent TNF-{alpha} induced cell death. CD4+CD25+ and CD4+CD25– cells were activated in vitro for 4 days. Supernatant (sup) was added to cultures of WEHI cells in the presence of varying amounts of rTNF-{alpha}. Depicted is the percentage of WEHI cells surviving the culture for 20 h. B, TNFRII shed by Treg cells is required to prevent TNF-{alpha}-induced cell death. CD4+CD25+ cells from naive WT or TNFRII KO mice were isolated and the supernatant of cell cultures was used in the WEHI cell bioassay in the presence of 0.5 pg/ml rTNF-{alpha} (*, p < 0.001; Et., etanercept). Representative data from 11 independent experiments are shown in A and B. C, CD4+CD25+ cells from TNFRII KO and WT mice are equally capable of suppressing Teff. A conventional T cell suppression assay was performed as control for Treg cell activity using CD4+CD25+ T cells from WT or TNFRII KO mice as suppressor cells. Percentages depict the percentages of inhibition of proliferation. Representative data from nine experiments are shown.

 
CD4+CD25+ Treg cell-derived sTNFRII modulates LPS-induced IL-6 production in vivo

TNF-{alpha} modulates the kinetics of IL-6 expression following LPS injection in mice (13, 14). IL-6, in turn, induces the expression of acute phase proteins. Thus, we reasoned that the reduction of the acute phase response observed previously (7) could be due to Treg cell-derived sTNFRII. To analyze this possibility, we injected mice i.p. with LPS 1 h after injection of CD4+CD25+ Treg cells from either WT or TNFRII KO mice. Serum IL-6 levels were analyzed at different time points following LPS injection.

At 4 and 6 h after LPS-injection, treatment with etanercept significantly reduced the amount of IL-6 produced in response to LPS, confirming that, indeed, TNF-{alpha} is involved in the induction of IL-6 following LPS injection (Fig. 3). Likewise, adoptive transfer of CD4+CD25+ Treg cells isolated from WT animals significantly decreased IL-6 production. In contrast, CD4+CD25+ Treg cells isolated from TNFRII KO animals lacked this ability, indicating that Treg cell-derived TNFRII is involved in the inhibition of the IL-6 response following injection of LPS. Together, these data show that CD4+CD25+ Treg cells can inhibit the action of TNF-{alpha} and dampen inflammation by releasing sTNFRII.


Figure 3
View larger version (27K):
[in this window]
[in a new window]

  		FIGURE 3. Treg cells inhibit LPS-induced IL-6 production through TNFR-shedding. CD4+CD25+ cells were isolated from either WT animals or TNFRII KO animals and activated in vitro for 4 days as described. Cells (1 x 106) were injected into mice receiving 150 µg of LPS i.p. 1 h later. Serum IL-6 levels were determined 4 and 6 h after LPS injection. One representative experiment of four is shown (conc., concentration; Et., etanercept).

 
TNFR-shedding by human CD4+CD25high T cells

Given the potential implications of our findings with murine Treg for the treatment of TNF-mediated inflammatory disorders, we next investigated whether TNFR shedding would also be a feature of human Treg.

We first analyzed TNFRII-expression on freshly isolated human CD4+ T cells. TNFRII expression was found to be highest on CD4+CD25high T cells but could also be detected on CD4+CD25int (where "int" is intermediate) and on a minor fraction of CD4+CD25– T cells (Fig. 4A). In line with this, TNFRII expression was highest on, but not exclusively confined to, CD4+FoxP3+ T cells. Phenotypic analysis using markers relevant for T cell function revealed that CD4+TNFRII+ T cells were largely CD45RO+CD45RA– (Fig. 4B). Whereas CD4+TNFRII– T cells uniformly expressed CCR7 but no HLA-DR and were mostly CD62Lhigh, CD4+TNFRII+ T cells exhibited a more heterogeneous expression of these markers. Interestingly, FoxP3 expression was restricted to TNFRII+ T cells. Thus, CD4+CD25highFoxP3+ T cells that display both effector and central memory markers (15) constitutively express TNFRII and have in part lost expression of the homing receptors CD62L and CCR7.


Figure 4
View larger version (41K):
[in this window]
[in a new window]

  		FIGURE 4. Phenotype of TNFRII-expressing human CD4+ T cells. A, Cell surface expression of TNFRII on freshly isolated human PBMC from healthy donors. TNFRII expression is highest on CD4+CD25high cells that coexpress FoxP3. B, Phenotypical analysis of CD4+TNFRII+ (open histogram) vs CD4+TNFRII– (filled histogram) T cells. Gating was based on an appropriate isotype control. Data are representative of four independent experiments.

 
Similar to the experiments performed in mice, CD4+CD25high and CD4+CD25– T cells were subsequently purified by FACS sorting and activated in vitro for up to 5 days. TCR stimulation induced strong up-regulation of TNFRII surface expression on CD4+CD25high and, to a lesser extent, on CD4+CD25– T cells during 5 days in culture (Fig. 5A). Cultures were performed in the presence or absence of marimastat, an inhibitor of metalloproteinases such as TNF-{alpha} converting enzyme (TACE, ADAM17), the enzyme responsible for the cleavage of TNFR from the cell surface. Inhibition of TNFR shedding by marimastat led to a strong accumulation of TNFRII on the cell surface of CD4+CD25high T cells as determined by an increase in mean fluorescence intensity (MFI) of the TNFRII staining. Activation of CD4+CD25– T cells under the same conditions, however, led to an only weak increase in TNFRII MFI, indicating lower shedding activity. In line with this observation, large amounts of sTNFRII were detectable in culture supernatants of CD4+CD25high T cells, with much lower levels being produced by CD4+CD25– T cells (Fig. 5B). sTNFRI was almost undetectable in cultures of both cell types (data not shown). The difference in TNFRII levels was even more prominent when adjusting TNFRII levels in supernatants for cell counts, taking into account the stronger proliferation of CD4+CD25– T cells. In addition, calculation of the amount of TNFRII shed from day to day revealed that the shedding activity of CD4+CD25– T cells reached a peak between day 3 and 4, whereas TNFRII-shedding of CD4+CD25high T cells still increased (Fig. 5C). It is unlikely that the sTNFRII levels determined originate from activated Teff cells contaminating the CD4+CD25high T cell population, as FACS sorting and subsequent activation of CD4+CD25int T cells led to substantially lower amounts of sTNFRII in culture supernatants than activation of CD4+CD25high T cells (data not shown). Interestingly, surface staining with HLA-DR of CD4+CD25high T cells from two donors activated in the presence or absence of marimastat revealed that CD4+CD25highHLA-DR+ T cells had substantially higher shedding capacity than CD4+CD25highHLA-DR– T cells (Fig. 5D). Within the Treg cell compartment, HLA-DR has previously been described to define a population with enhanced suppressive ability. Our data indicate that the TNFR shedding capacity differs between these two subsets. This might be relevant for the in vivo function of Treg cells and further emphasizes that human Treg cell populations are composed of functionally distinct subsets (16).


Figure 5
View larger version (20K):
[in this window]
[in a new window]

  		FIGURE 5. Characteristics of TNFRII shedding by human CD4+CD25high T cells. A, MFI of TNFRII staining after culture in the presence or absence of marimastat (M). The inset depicts the increase in MFI on marimastat-treated CD25high or CD25– (CD25neg) cells as the area between (betw.) the respective curves. B, Levels of sTNFRII in supernatants of cells after activation (*, p < 0.05; **, p < 0.01). C, Levels of sTNFRII produced from day to day (d) adjusted for cell count. Cells were manually counted at each time point in duplicate. The amount of sTNFRII produced from one day to the next was divided by the average cell number present in the wells at these time points using the formula: (conc. sTNFRII dayx + 1 – conc. sTNFRII dayx)/(1/2 x (cell count (x105) dayx + cell count (x105) dayx + 1)) (where "conc." is concentration; *, p < 0.05). Results presented in A–C are representative of five independent experiments. D, Increase in MFI of TNFRII staining on CD4+CD25highHLA-DR+ (DR+) and CD4+CD25highHLA-DR– (DR–) T cells from two separate donors after 5 days of activation in the presence and absence of marimastat. Increase in MFI of HLA-DR+ cells was normalized to 100 to account for overall differences in HLA-DR expression levels between donors.

 
In summary, we describe in this article a new mechanism of action of CD4+CD25+ Treg cells. Our results are in line with recent observations describing that TNF-{alpha} can transiently silence the suppressive activity of Treg cells through signaling via TNFRII (17, 18). Interestingly, suppressive function was found to be restored after several days (18). Our findings showing that TNFRII is shed several days after the activation of Treg cells fit well with these observations, as the shedding of TNFRII would allow Treg cells to counteract the action of TNF-{alpha}, thereby circumventing its inhibitory effect on Treg cell function. This way, Treg cells could regain their suppressive ability to regulate the function of Teff cells and, at the same time, suppress the effects of TNF-{alpha}, a crucial mediator of acute and chronic inflammation.

We have previously shown that CD4+CD25+ T cells can be used effectively in the treatment of collagen-induced arthritis (CIA), a model for systemic arthritis in mice (7, 19). Collagen-induced arthritis is primarily an Ab driven disease (20, 21) and the role of T cells is, most likely, restricted to the provision of help to B cells that produce collagen type II-specific Abs. As CD4+CD25+ Treg cells are able to reduce arthritis severity in the effector phase of the disease without affecting circulating anti-CII Abs, it is likely that the shedding of sTNFR by adoptively transferred Treg cells is involved in the inhibition of arthritis.

Finally, our data obtained with human Treg cells indicate that the mechanism we show in mice is essentially similar in the human setting. Although constitutive TNFRII expression is not confined to Treg cells, human CD4+CD25high T cells exhibit a much stronger and more sustained shedding activity upon activation when compared with CD4+CD25– T cells. This is of potential interest in the context of TNF-mediated autoimmune diseases such as rheumatoid arthritis, in which TNFRII-Ig fusion proteins are used effectively in therapeutic settings. Together, these data provide a rationale for the therapeutic use of Treg cells in systemic autoimmune diseases.


   Acknowledgments
 
We thank G. de Roo, R. van der Linden, and M. van der Hoorn for FACS sort purification of T cell subsets. Roeland Hanemaaijer (TNO, Leiden, The Netherlands) provided the metalloproteinase inhibitor marimastat.


   Disclosures
Top
 Abstract
 Introduction
 Materials and Methods
 Results and Discussion
 Disclosures
References
 
The authors have no financial conflict of interest.


   Footnotes
 
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1 This study was supported by Dutch Arthritis Foundation Grant 02-I-402 and by research funding from the European Community FP6 funding project 018661 Autocure. The work of R.E.M.T. was supported by a Vidi Grant from the Netherlands Organization for Scientific Research. H.U.S. was supported by a Pfizer Articulum Fellowship. Back

2 G.J.D.v.M., H.U.S., and M.H. contributed equally to this work. Back

3 Address correspondence and reprint requests to Dr. René E. M. Toes, Department of Rheumatology, Postal Zone C1-R, Leiden University Medical Center, P.O. Box 9600, 2300 RC, Leiden, The Netherlands. E-mail address: R.E.M.Toes{at}lumc.nl Back

4 Abbreviations used in this paper: Treg cell, CD4+CD25+ regulatory T (cell); KO, knockout; MFI, mean fluorescence intensity; sTNFR, soluble TNF-receptor; Teff, effector T (cell); WT, wild type. Back

Received for publication November 20, 2007. Accepted for publication December 28, 2007.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results and Discussion
 Disclosures
 References
 

  1. Belkaid, Y., B. T. Rouse. 2005. Natural regulatory T cells in infectious disease. Nat. Immunol. 6: 353-360. [Medline]
  2. Sakaguchi, S.. 2005. Naturally arising Foxp3-expressing CD25+CD4+ regulatory T cells in immunological tolerance to self and non-self. Nat. Immunol. 6: 345-352. [Medline]
  3. Shevach, E. M., R. A. DiPaolo, J. Andersson, D. M. Zhao, G. L. Stephens, A. M. Thornton. 2006. The lifestyle of naturally occurring CD4+CD25+Foxp3+ regulatory T cells. Immunol. Rev. 212: 60-73. [Medline]
  4. Waldmann, H., L. Graca, S. Cobbold, E. Adams, M. Tone, Y. Tone. 2004. Regulatory T cells and organ transplantation. Semin. Immunol. 16: 119-126. [Medline]
  5. Tang, Q., E. K. Boden, K. J. Henriksen, H. Bour-Jordan, M. Bi, J. A. Bluestone. 2004. Distinct roles of CTLA-4 and TGF-β in CD4+CD25+ regulatory T cell function. Eur. J. Immunol. 34: 2996-3005. [Medline]
  6. von Boehmer, H.. 2005. Mechanisms of suppression by suppressor T cells. Nat. Immunol. 6: 338-344. [Medline]
  7. Morgan, M. E., R. Flierman, L. M. van Duivenvoorde, H. J. Witteveen, W. van Ewijk, J. M. van Laar, R. R. de Vries, R. E. Toes. 2005. Effective treatment of collagen-induced arthritis by adoptive transfer of CD25+ regulatory T cells. Arthritis Rheum. 52: 2212-2221. [Medline]
  8. Gauldie, J., C. Richards, D. Harnish, P. Lansdorp, H. Baumann. 1987. Interferon β2/B-cell stimulatory factor type 2 shares identity with monocyte-derived hepatocyte-stimulating factor and regulates the major acute phase protein response in liver cells. Proc. Natl. Acad. Sci. USA 84: 7251-7255. [Abstract/Free Full Text]
  9. Fattori, E., M. Cappelletti, P. Costa, C. Sellitto, L. Cantoni, M. Carelli, R. Faggioni, G. Fantuzzi, P. Ghezzi, V. Poli. 1994. Defective inflammatory response in interleukin 6-deficient mice. J. Exp. Med. 180: 1243-1250. [Abstract/Free Full Text]
  10. Gabay, C., I. Kushner. 1999. Acute-phase proteins and other systemic responses to inflammation. N. Engl. J. Med. 340: 448-454. [Free Full Text]
  11. Wang, J., A. Ioan-Facsinay, E. I. van der Voort, T. W. Huizinga, R. E. Toes. 2007. Transient expression of FOXP3 in human activated nonregulatory CD4+ T cells. Eur. J. Immunol. 37: 129-138. [Medline]
  12. Espevik, T., J. Nissen-Meyer. 1986. A highly sensitive cell line, WEHI 164 clone 13, for measuring cytotoxic factor/tumor necrosis factor from human monocytes. J. Immunol. Methods 95: 99-105. [Medline]
  13. Amiot, F., C. Fitting, K. J. Tracey, J. M. Cavaillon, F. Dautry. 1997. Lipopolysaccharide-induced cytokine cascade and lethality in LT{alpha}/TNF{alpha}-deficient mice. Mol. Med. 3: 864-875. [Medline]
  14. Marino, M. W., A. Dunn, D. Grail, M. Inglese, Y. Noguchi, E. Richards, A. Jungbluth, H. Wada, M. Moore, B. Williamson, et al 1997. Characterization of tumor necrosis factor-deficient mice. Proc. Natl. Acad. Sci. USA 94: 8093-8098. [Abstract/Free Full Text]
  15. Sallusto, F., J. Geginat, A. Lanzavecchia. 2004. Central memory and effector memory T cell subsets: function, generation, and maintenance. Annu. Rev. Immunol. 22: 745-763. [Medline]
  16. Baecher-Allan, C., E. Wolf, D. A. Hafler. 2006. MHC class II expression identifies functionally distinct human regulatory T cells. J. Immunol. 176: 4622-4631. [Abstract/Free Full Text]
  17. Valencia, X., G. Stephens, R. Goldbach-Mansky, M. Wilson, E. M. Shevach, P. E. Lipsky. 2006. TNF downmodulates the function of human CD4+CD25hi T-regulatory cells. Blood 108: 253-261. [Abstract/Free Full Text]
  18. Chen, X., M. Baumel, D. N. Mannel, O. M. Howard, J. J. Oppenheim. 2007. Interaction of TNF with TNF receptor type 2 promotes expansion and function of mouse CD4+CD25+ T regulatory cells. J. Immunol. 179: 154-161. [Abstract/Free Full Text]
  19. Morgan, M. E., R. P. Sutmuller, H. J. Witteveen, L. M. van Duivenvoorde, E. Zanelli, C. J. Melief, A. Snijders, R. Offringa, R. R. de Vries, R. E. Toes. 2003. CD25+ cell depletion hastens the onset of severe disease in collagen-induced arthritis. Arthritis Rheum. 48: 1452-1460. [Medline]
  20. Holmdahl, R., K. Rubin, L. Klareskog, E. Larsson, H. Wigzell. 1986. Characterization of the antibody response in mice with type II collagen-induced arthritis, using monoclonal anti-type II collagen antibodies. Arthritis Rheum. 29: 400-410. [Medline]
  21. Holmdahl, R., L. Jansson, A. Larsson, R. Jonsson. 1990. Arthritis in DBA/1 mice induced with passively transferred type II collagen immune serum. Immunohistopathology and serum levels of anti-type II collagen auto-antibodies. Scand J. Immunol. 31: 147-157. [Medline]




This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by van Mierlo, G. J. D.
Right arrow Articles by Toes, R. E. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by van Mierlo, G. J. D.
Right arrow Articles by Toes, R. E. M.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS