HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Davidson, T. S. Articles by Shevach, E. M. Search for Related Content PubMed PubMed Citation Articles by Davidson, T. S. Articles by Shevach, E. M.

Cutting Edge: IL-2 Is Essential for TGF--Mediated Induction of Foxp3⁺ T Regulatory Cells

Cellular Immunology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892

	Abstract

Top Abstract Introduction Materials and Methods Results and Discussion Disclosures References

 
TGF- is a pluripotent cytokine that is capable of inducing the expression of Foxp3 in naive T lymphocytes. TGF--induced cells are phenotypically similar to thymic-derived regulatory T cells in that they are anergic and suppressive. We have examined the cytokine and costimulatory molecule requirements for TGF--mediated induction and maintenance of Foxp3 by CD4⁺Foxp3^– cells. IL-2 plays a non-redundant role in TGF--induced Foxp3 expression. Other common -chain-utilizing cytokines were unable to induce Foxp3 expression in IL-2-deficient T cells. The role of CD28 in the induction of Foxp3 was solely related to its capacity to enhance the endogenous production of IL-2. Foxp3 expression was stable in vitro and in vivo in the absence of IL-2. As TGF--induced T regulatory cells can be easily grown in vitro, they may prove useful for the treatment of autoimmune diseases, for the prevention of graft rejection, and graft versus host disease.

	Introduction

Top Abstract Introduction Materials and Methods Results and Discussion Disclosures References

 
Regulatory T cells (Treg)² are responsible for limiting most immune responses and inhibiting the induction of autoimmunity (1). Although Treg were originally identified as CD4⁺CD25⁺ T cells, more recent studies have defined naturally occurring Treg (nTreg) as expressing the forkhead family transcription factor, Foxp3. Although Foxp3 is necessary for the development of nTreg in the thymus, it may not be sufficient. A number of studies have examined the requirement for cytokines for nTreg development. Engagement of CD28 is critical for the generation of Treg (2), but IL-2 does not appear to be required (3) for the generation of Foxp3⁺ nTreg in vivo. The role of IL-2 in the maintenance and function of nTreg in the periphery still remains to be clarified (3, 4, 5, 6). Although TGF--deficient mice develop an autoimmune syndrome (7) similar to that of Foxp3^–/– mice, nTreg develop normally in the thymus in the absence of TGF-, but their maintenance and function in the periphery may be compromised (8).

In contrast to the requirement for the development of Foxp3⁺ nTreg in the thymus, recent reports (9, 10) have demonstrated that peripheral CD4⁺Foxp3^– T cells can be induced in vitro to express Foxp3 in the presence of TGF-. These induced cells, termed iTregs, are functionally similar to nTregs in that they are anergic, suppressive, and capable of inhibiting disease in vivo. In this study, we have examined the cytokine and costimulatory molecule requirements for the TGF--mediated induction and maintenance of Foxp3 by CD4⁺CD25^– cells. Although signaling via CD28 is not required, IL-2 plays a critical role in the induction, but not the maintenance of Foxp3 expression in vitro and in vivo.

	Materials and Methods

Top Abstract Introduction Materials and Methods Results and Discussion Disclosures References

 
Mice

B10.A 5CC7 TCR-Tg Rag2^–/– and B10.A 5CC7 TCR-Tg Rag2^–/– IL-2^–/– mice were obtained from Taconic Farms. C57BL/6 mice were obtained from Jackson ImmunoResearch Laboratories. Mice were housed under specific pathogen free conditions in the National Institute of Allergy and Infectious Disease animal facility and used at 6- to 10-weeks of age.

Cytokines, reagents, and antibodies

Recombinant human TGF- was obtained from R&D Systems and used at 5 ng/ml. Human recombinant IL-2 was purchased from Peprotech and used at 100 U/ml. All other cytokines were purchased from R&D Systems and used at 10 ng/ml. Abs to mouse CD3, CD28, and CD4-FITC were obtained from BD Biosciences. The anti-Foxp3 Alexa Fluor 647 Ab clone 150D was obtained from BioLegend. The anti-IFN- Ab XMG1.2, anti-IL-4 Ab 11B11, and anti-IL-2 Ab S4B6 were generated in our laboratory and used as ascites. CFSE was obtained from Molecular Probes and used at a final concentration of 1 µM.

Cell purification and media

Lymph nodes and spleens were harvested from mice that had been sacrificed by CO₂ asphyxiation. They were mechanically dissociated and strained through a 40-µm nylon mesh to produce a single cell suspension. RBC were lysed using ACK lysis buffer (BioWhittaker). The cells were labeled with CD4 beads (Miltenyi Biotec) and positively selected using an AutoMacs (Miltenyi Biotec). The cells were washed with PBS then resuspended in RPMI 1640 (BioSource) medium that contained 10% heat-inactivated FBS, 2-ME, HEPES, non-essential amino acids, penicillin, streptomycin, and L-glutamine.

Th neutral, Th1 and Th2 differentiation

Purified CD4⁺ T cells were cultured in 24-well plates (Corning Costar) with plate-bound anti-CD3 and anti-CD28 Abs. For Th1 differentiation, the cells were cultured in the presence of 10 ng/ml IL-12 and 10 µg/ml anti-IL-4. For Th2 differentiation the cells were cultured with 10 ng/ml IL-4 and 10 µg/ml anti-IFN-. Th neutral cells were generated by culture without any Abs or exogenous cytokines. The cells were differentiated for 1 week. Differentiation was assayed by restimulating the cells with PMA/ionomycin followed by intracellular staining for IFN- and IL-4.

Cell culture and FACS analysis

Purified CD4⁺ T cells were cultured in 24-well plates (Corning Costar) in the presence of plate-bound anti-CD3 and anti-CD28 Abs. Unless otherwise noted, all wells were coated with 2 µg/well of each Ab for 2 h at 37°C in PBS. Cells were cultured at an initial density of 2.5–5 x 10⁵ cells per well. At the end of the culture period, the cells were harvested, washed with PBS and stained with CD4-FITC in PBS containing 0.5% BSA (PBS-BSA) at 4°C for 15 min. The cells were then washed with PBS-BSA and permeabilized overnight in Fix/perm buffer (eBioscience). The cells were then washed once in PBS-BSA, then once again in permeabilization buffer (eBioscience). Nonspecific binding sites were blocked with a 1/100 dilution of rat Ig (Jackson ImmunoResearch Laboratories) for 15 min at 4°C and then the cells were stained with the anti-Foxp3-AF647 clone 150D at a final dilution of 1/150 for 45 min at 4°C. The cells were then washed, resuspended in PBS, and analyzed on a FACSCalibur (BD Biosciences).

Proliferation assays

CD4⁺CD25^– responder cells were purified from lymph nodes by first depleting the CD25+ fraction, then positively selecting the CD4⁺ fraction with magnetic beads on an AutoMacs (Miltenyi Biotec). T-depleted spleen cells were obtained by depletion of Thy1.2⁺ cells with magnetic beads. Responder cells (5 x 10⁴) were cultured with an equal number of T-depleted spleen cells as APC in the presence of 0.5 µg/ml anti-CD3 (clone 2C11) in 96-well microtiter plates for 72 h. [³H]TdR (1 µCi/well) was added for the final 6 h. The cultures were then harvested and [³H]TdR incorporation measured by scintillation counting.

	Results and Discussion

Top Abstract Introduction Materials and Methods Results and Discussion Disclosures References

 
The ability of TGF- to induce Foxp3 expression in CD4⁺CD25^–Foxp3^– cells was evaluated by stimulating a homogenous population of CFSE-labeled CD4⁺Foxp3^– T cells from a TCR transgenic mouse on a Rag^–/– background with plate-bound anti-CD3 and anti-CD28 in the presence of TGF- in medium containing IL-2. TCR transgenic Rag^–/– animals do not contain an endogenous population of Foxp3+ cells, thus any Foxp3 expression detected as a result of TGF- treatment would result from de novo expression. At 48 h after stimulation, nearly 50% of the TGF--treated cells were Foxp3⁺, whereas <1% of the cells stimulated in the absence of the cytokine were Foxp3⁺ (Fig. 1A). The number of Foxp3-expressing cells continued to increase to 73% by 72 h, and reached a maximum of 83% at 96 h. In contrast, <1% of the cells not treated with TGF- were Foxp3⁺ by 72 h, and only 2% of the cells stained positive for Foxp3 at 96 h. TGF- treatment did not affect the ability of the cells to proliferate as indicated by identical CFSE dilution in the treated and untreated groups. These results are consistent with previous data that demonstrated that TGF- is capable of inhibiting T cell proliferation when the cells are stimulated with anti-CD3 alone, but that this inhibition is overcome in the presence of CD28 costimulation (11).

View larger version (39K): [in this window] [in a new window]   FIGURE 1. TGF- induces Foxp3 expression in an IL-2-dependent manner. A, 5CC7 TCR-Tg Rag–/– CD4+ T cells were purified, labeled with CFSE, and stimulated with plate-bound anti-CD3 and anti-CD28 Abs in the presence of exogenous IL-2 either with (top panels) or without (bottom panels) 5 ng/ml TGF-. At the indicated time points, cells were harvested and analyzed for Foxp3 expression and CFSE dilution by flow cytometry. B, CD4+5CC7 TCR-Tg Rag–/– T cells were cultured on plate-bound anti-CD3 (2 µg/well) with and without the addition of plate-bound anti-CD28 (2 µg/well) in medium that contained either no exogenous cytokines or medium that contained 100 U/ml IL-2. The cells were cultured for 48 h and analyzed for the expression of CD4 and Foxp3 by flow cytometry. C, Purified CD4+5CC7 TCR-Tg Rag–/–IL-2–/– T cells were stimulated with plate-bound anti-CD3 or anti-CD3 plus anti-CD28 in the presence or absence of exogenous IL-2. At 72 h, the cells were stained for Foxp3 expression. The percentage of live CD4+Foxp3+ cells is displayed on the y-axis. D, Purified CD4+5CC7 TCR-Tg Rag–/– T cells were cultured in medium that contained no exogenous cytokines with the indicated concentrations of anti-CD3 (µg/well). Plate-bound anti-CD28 was used at a concentration of 2 µg/well in all indicated cultures. The cells were cultured for 72 h, and analyzed for expression of Foxp3 by flow cytometry. The percentage of Foxp3+ cells is displayed on the y-axis.

We also evaluated the role of the strength of the TCR signal required to up-regulate Foxp3 in the presence of TGF-. CD4⁺Foxp3^– T cells were stimulated with varying concentrations of plate-bound anti-CD3 without any exogenous IL-2. The role of CD28 costimulation was also investigated by adding a fixed concentration of plate-bound anti-CD28. In the absence of CD28 costimulation, Foxp3 expression was maximal at 2 µg/well anti-CD3, whereas significant Foxp3 levels were not detectable below 0.4 µg/well of anti-CD3 (Fig. 1D). In the presence of CD28 costimulation, maximal Foxp3 expression was seen at 25-fold lower concentrations of anti-CD3 stimulation. In separate experiments, we directly compared the ability of TGF- to induce Foxp3 when T cells were stimulated either by plate-bound anti-CD3 and anti-CD28 Abs, soluble anti-CD3 anti-CD28 in the presence of bone marrow-derived dendritic cells (BMDC), or BMDC with cognate Ag. All conditions induced identical levels of Foxp3 expression (data not shown).

We next determined whether these TGF--treated Foxp3-expressing cells were capable of suppressing the proliferation of a naive population of effector T cells. CD4⁺CD8^–CD25^– thymocytes were stimulated in the presence or absence of TGF- with exogenous IL-2, anti-CD3, and T-depleted spleen cells for 5 days. The cells were then washed and transferred to medium containing IL-2 for 72 h. The suppressive activity of the cells was then assayed by co-culturing them at various ratios with CD4⁺CD25^– responder cells, anti-CD3, and T-depleted spleen cells as APC. Proliferation was assessed at 72 h by thymidine incorporation. In the presence of the TGF--treated cells, proliferation was potently reduced, whereas the non-TGF--treated cells actually enhanced proliferation (Fig. 2). Thus, TGF- treatment of CD4⁺CD25^–Foxp3^– T cells results in Foxp3 expression and a suppressive phenotype.

View larger version (12K): [in this window] [in a new window]   FIGURE 2. TGF--induced Foxp3+ cells are suppressive. CD4+CD25–CD8– thymocytes from BALB/c mice were stimulated in the presence or absence of TGF- with IL-2, anti-CD3 and T-depleted splenocytes (TdS) for 5 days. The cells were then washed and placed in medium containing IL-2 with no further TCR stimulus for an additional 72 h. The TGF--treated cells used in this experiment were 90% positive for Foxp3. The cells were then cultured with the indicated ratios of induced cells to CD4+CD25– responder cells as described in Materials and Methods. Results are expressed as cpm.

View larger version (37K): [in this window] [in a new window]   FIGURE 3. Foxp3 expression cannot be induced in previously differentiated cells. CD4+5CC7 TCR-Tg Rag–/– T cells were purified and differentiated in vitro for 1 wk under Th-neutral, Th1, or Th2 conditions as described in Materials and Methods. The cells were then restimulated for 48 h with or without 5 ng/ml TGF- on 2 µg/well each plate-bound anti-CD3 and anti-CD28 Abs in the presence of 100 U/ml IL-2. The cells were then analyzed for CD4 and Foxp3 expression by flow cytometry.

View larger version (18K): [in this window] [in a new window]   FIGURE 4. IL-2 is non-redundant in allowing TGF--mediated Foxp3 expression but is not required for maintenance of Foxp3 expression in vivo. A, CD4+5CC7 TCR-Tg Rag–/– T cells on either an IL-2 sufficient (here referred to as WT) or IL-2–/– background were purified and stimulated in the presence of the indicated cytokines on plate-bound anti-CD3 and anti-CD28 Abs with 5 ng/ml TGF- for 72 h. The control group is no cytokine in addition to TGF-. The cells were then harvested and analyzed for the expression of Foxp3 by flow cytometry. The percentage of Foxp3+ cells is displayed on the y-axis. B, CD4+5CC7 TCR-Tg Rag–/– T cells were purified and stimulated on plate-bound anti-CD3 and anti-CD28 Abs in the presence TGF- and 100 U/ml exogenous IL-2 for 1 week. One million cells were labeled with CFSE and then transferred into either 5CC7 TCR-Tg Rag–/– or 5CC7 TCR-Tg Rag–/– IL-2–/– recipients. Seven days later, the animals were sacrificed, lymph nodes collected and stained with allophycocyanin-conjugated anti-CD4 and PE-conjugated anti-Foxp3 and analyzed by flow cytometry. Foxp3 expression by CD4+CFSE+ cells is displayed in the histogram.

These results confirm and extend earlier studies (9, 10, 12) on the capacity of TGF- to induce Foxp3⁺ T cells. In many respects, these iTreg behave in an identical fashion to thymic-derived nTreg in vitro and in vivo in terms of their suppressive activity. However, our results demonstrate several major differences in the requirements for IL-2 and CD28 costimulation in the induction of Foxp3 expression in nTreg compared with iTreg. The studies of Fontenot et al. (3) using mice containing a Foxp3^gfp "knockin allele" clearly demonstrate that IL-2 is not required for the development of nTreg in the thymus although it likely plays a role in their maintenance and metabolic state in the periphery. In contrast, our studies demonstrate an absolute requirement for IL-2 in concert with TGF- for induction of Foxp3⁺ iTreg in the periphery. We have not excluded a role for cytokines other than the ones we have tested, but other cytokines that utilize the c-chain as part of their receptor complexes were completely ineffective. Once induced, Foxp3 expression was stable both in vitro and in vivo in the absence of IL-2. It remains possible that IL-2 is still required for the long-term maintenance of Foxp3⁺ iTreg, but we have not conducted the in vivo studies for longer than 2 weeks in IL-2^–/– mice although it is stable for 50 days in IL-2-sufficient mice (R. J. DiPaolo, T. S. Davidson, J. Andersson, E. M. Shevach, manuscript in preparation). A second major difference between nTreg and iTreg is that the development of nTreg required CD28-mediating signaling in addition to those required for IL-2 production (2), whereas the role of CD28 in the induction of iTreg appears to be solely related to its capacity to enhance the endogenous production of IL-2.

One major question that remains unresolved by these studies is whether and under what conditions iTreg are generated in vivo. It remains unknown whether any of the Foxp3⁺ T cells in mouse or more importantly in man are derived in the periphery by this TGF--dependent induction pathway. It is likely that inflammatory infiltrates would contain sufficient quantities of both TGF- and IL-2, so this induction pathway should be operative in vivo. However, such infiltrates would also contain proinflammatory cytokines, such as IL-6, that could subvert the induction of iTreg and result in the induction of IL-17 producing T cells (12). The therapeutic potential of TGF- iTreg also remains to be determined. Our results indicate that T cells recently activated in vitro cannot be induced to express Foxp3. As most autoantigen-specific cells that might be isolated from patients are also likely to be memory T cells, it may be difficult to convert them to iTreg expressing Foxp3. On the other hand, alloantigen-specific TGF- iTreg might be readily induced from naive precursors and should prove useful for the treatment of graft rejection and graft-vs-host disease.

	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 Address correspondence and reprint requests to Dr. Ethan M. Shevach, National Institutes of Health, Laboratory of Immunology, Section of Cellular Immunology, Building 10, 11N315, Bethesda, MD 20892-1892. E-mail address: eshevach{at}niaid.nih.gov

² Abbreviations used in this paper: Treg, regulatory T cell; nTreg, naturally occurring Treg; BMDC, bone marrow-derived dendritic cell.

Received for publication August 1, 2006. Accepted for publication January 31, 2007.

	References

Top Abstract Introduction Materials and Methods Results and Discussion Disclosures References

 

1. Sakaguchi, S.. 2004. Naturally arising CD4⁺ regulatory T cells for immunologic self-tolerance and negative control of immune responses. Annu. Rev. Immunol. 22: 531-562. [Medline]
2. Tai, X., M. Cowan, L. Feigenbaum, A. Singer. 2005. CD28 costimulation of developing thymocytes induces Foxp3 expression and regulatory T cell differentiation independently of interleukin 2. Nat. Immunol. 6: 152-162. [Medline]
3. Fontenot, J. D., J. P. Rasmussen, M. A. Gavin, A. Y. Rudensky. 2005. A function for interleukin 2 in Foxp3-expressing regulatory T cells. Nat. Immunol. 6: 1142-1151. [Medline]
4. Thornton, A. M., E. E. Donovan, C. A. Piccirillo, E. M. Shevach. 2004. Cutting edge: IL-2 is critically required for the in vitro activation of CD4⁺CD25⁺ T cell suppressor function. J. Immunol. 172: 6519-6523. [Abstract/Free Full Text]
5. Setoguchi, R., S. Hori, T. Takahashi, S. Sakaguchi. 2005. Homeostatic maintenance of natural Foxp3⁺ CD25⁺ CD4⁺ regulatory T cells by interleukin (IL)-2 and induction of autoimmune disease by IL-2 neutralization. J. Exp. Med. 201: 723-735. [Abstract/Free Full Text]
6. Bayer, A. L., A. Yu, D. Adeegbe, T. R. Malek. 2005. Essential role for interleukin-2 for CD4⁺CD25⁺ T regulatory cell development during the neonatal period. J. Exp. Med. 201: 769-777. [Abstract/Free Full Text]
7. Shull, M. M., I. Ormsby, A. B. Kier, S. Pawlowski, R. J. Diebold, M. Yin, R. Allen, C. Sidman, G. Proetzel, D. Calvin, et al 1992. Targeted disruption of the mouse transforming growth factor- 1 gene results in multifocal inflammatory disease. Nature 359: 693-699. [Medline]
8. Marie, J. C., J. J. Letterio, M. Gavin, A. Y. Rudensky. 2005. TGF-1 maintains suppressor function and Foxp3 expression in CD4⁺CD25⁺ regulatory T cells. J. Exp. Med. 201: 1061-1067. [Abstract/Free Full Text]
9. Fantini, M. C., C. Becker, G. Monteleone, F. Pallone, P. R. Galle, M. F. Neurath. 2004. Cutting edge: TGF- induces a regulatory phenotype in CD4⁺CD25^– T cells through Foxp3 induction and down-regulation of Smad7. J. Immunol. 172: 5149-5153. [Abstract/Free Full Text]
10. Chen, W., W. Jin, N. Hardegen, K. J. Lei, L. Li, N. Marinos, G. McGrady, S. M. Wahl. 2003. Conversion of peripheral CD4⁺CD25^– naive T cells to CD4⁺CD25⁺ regulatory T cells by TGF- induction of transcription factor Foxp3. J. Exp. Med. 198: 1875-1886. [Abstract/Free Full Text]
11. Sung, J. L., J. T. Lin, J. D. Gorham. 2003. CD28 co-stimulation regulates the effect of transforming growth factor-1 on the proliferation of naive CD4⁺ T cells. Int. Immunopharmacol. 3: 233-245. [Medline]
12. Bettelli, E., Y. Carrier, W. Gao, T. Korn, T. B. Strom, M. Oukka, H. L. Weiner, V. K. Kuchroo. 2006. Reciprocal developmental pathways for the generation of pathogenic effector TH17 and regulatory T cells. Nature 441: 235-238. [Medline]

This article has been cited by other articles:

				L. Passerini, S. E. Allan, M. Battaglia, S. Di Nunzio, A. N. Alstad, M. K. Levings, M. G. Roncarolo, and R. Bacchetta STAT5-signaling cytokines regulate the expression of FOXP3 in CD4+CD25+ regulatory T cells and CD4+CD25- effector T cells Int. Immunol., March 1, 2008; 20(3): 421 - 431. [Abstract] [Full Text] [PDF]

				R. K. Selvaraj and T. L. Geiger Mitigation of Experimental Allergic Encephalomyelitis by TGF-{beta} Induced Foxp3+ Regulatory T Lymphocytes through the Induction of Anergy and Infectious Tolerance J. Immunol., March 1, 2008; 180(5): 2830 - 2838. [Abstract] [Full Text] [PDF]

				K. M. Elias, A. Laurence, T. S. Davidson, G. Stephens, Y. Kanno, E. M. Shevach, and J. J. O'Shea Retinoic acid inhibits Th17 polarization and enhances FoxP3 expression through a Stat-3/Stat-5 independent signaling pathway Blood, February 1, 2008; 111(3): 1013 - 1020. [Abstract] [Full Text] [PDF]

				J.-G. Chai, D. Coe, D. Chen, E. Simpson, J. Dyson, and D. Scott In Vitro Expansion Improves In Vivo Regulation by CD4+CD25+ Regulatory T Cells J. Immunol., January 15, 2008; 180(2): 858 - 869. [Abstract] [Full Text] [PDF]

				S. Yamazaki, A. J. Bonito, R. Spisek, M. Dhodapkar, K. Inaba, and R. M. Steinman Dendritic cells are specialized accessory cells along with TGF- for the differentiation of Foxp3+ CD4+ regulatory T cells from peripheral Foxp3 precursors Blood, December 15, 2007; 110(13): 4293 - 4302. [Abstract] [Full Text] [PDF]

				D. Q. Tran, H. Ramsey, and E. M. Shevach Induction of FOXP3 expression in naive human CD4+FOXP3 T cells by T-cell receptor stimulation is transforming growth factor-{beta} dependent but does not confer a regulatory phenotype Blood, October 15, 2007; 110(8): 2983 - 2990. [Abstract] [Full Text] [PDF]

				A. L. Christy and M. A. Brown The Multitasking Mast Cell: Positive and Negative Roles in the Progression of Autoimmunity J. Immunol., September 1, 2007; 179(5): 2673 - 2679. [Abstract] [Full Text] [PDF]

				T. So and M. Croft Cutting Edge: OX40 Inhibits TGF-beta- and Antigen-Driven Conversion of Naive CD4 T Cells into CD25+Foxp3+ T cells J. Immunol., August 1, 2007; 179(3): 1427 - 1430. [Abstract] [Full Text] [PDF]

				D. Mucida, Y. Park, G. Kim, O. Turovskaya, I. Scott, M. Kronenberg, and H. Cheroutre Reciprocal TH17 and Regulatory T Cell Differentiation Mediated by Retinoic Acid Science, July 13, 2007; 317(5835): 256 - 260. [Abstract] [Full Text] [PDF]

				R. K. Selvaraj and T. L. Geiger A Kinetic and Dynamic Analysis of Foxp3 Induced in T Cells by TGF-beta J. Immunol., June 15, 2007; 178(12): 7667 - 7677. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Davidson, T. S. Articles by Shevach, E. M. Search for Related Content PubMed PubMed Citation Articles by Davidson, T. S. Articles by Shevach, E. M.