|
|
||||||||
CUTTING EDGE |



Departments of
*
Medicine and
Pediatrics, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912;
Lexicon Genetics, The Woodlands, TX 77381; and
The Institute of Physical and Chemical Research, Research Center for Allergy and Immunology, Suehirocho, Tsurumi-ku, Yokohama, Japan
| Abstract |
|---|
|
|
|---|
, B220, DX5). In this study, we show that expression of the tryptophan-degrading enzyme indoleamine 2,3 dioxygenase (IDO) is selectively induced in specific splenic DC subsets when mice were exposed to the synthetic immunomodulatory reagent CTLA4-Ig. CTLA4-Ig did not induce IDO expression in macrophages or lymphoid cells. Induction of IDO completely blocked clonal expansion of T cells from TCR transgenic mice following adoptive transfer, whereas CTLA4-Ig treatment did not block T cell clonal expansion in IDO-deficient recipients. Thus, IDO expression is an inducible feature of specific subsets of DCs, and provides a potential mechanistic explanation for their T cell regulatory properties. | Introduction |
|---|
|
|
|---|
, B220, DX5, DEC205) suppress T cell responses and promote tolerance, rather than immunity, to specific Ags (1, 2, 3, 4, 5, 6). Expression of the tryptophan-catabolizing enzyme indoleamine 2,3 dioxygenase (IDO) in human and murine cells inhibits Ag-specific T cell proliferation in vitro and suppresses T cell responses to fetal alloantigens during murine pregnancy (7, 8, 9, 10). Correlations between IDO expression and immunoregulatory outcomes have been confirmed in several experimental systems (11, 12, 13, 14, 15). Recently, Grohmann et al. (16) reported that the synthetic immunomodulatory reagent CTLA4-Ig induces IDO expression in CD11c+ DCs from murine spleen. Using this method to induce IDO expression, we show that CTLA4-Ig induced IDO expression selectively in specific DC subsets. In a model of T cell adoptive transfer, we show that CTLA4-Ig completely blocked CD8+ T cell clonal expansion and that this property was IDO-dependent. | Materials and Methods |
|---|
|
|
|---|
C57BL6 (B6), CBA/Ca, and F1(CBA x B6) mice were bred in a specific pathogen-free facility. BM3 TCR transgenic mice have been described previously (7, 17, 18). IDO-deficient mice were generated using a DNA construct to target the IDO gene in murine embryonic stem cells (129/SvJ). A complete copy of the murine IDO gene was isolated from a genomic library (129/Sv) and a selectable marker (neomycin) was inserted to replace exons 35 (which encode critical portions of the enzyme catalytic site). In addition, a translational "stop" codon (TAG) was introduced into exon 2 sequences. Embryonic stem cells were electroporated, and clones carrying targeted IDO alleles were injected into blastocysts. Male chimeric mice were mated with B6 or CBA females, and offspring were mated to produce IDO-/- mice with either B6 or CBA backgrounds. The IDO-deficient mice bred normally, and exhibited no spontaneous autoimmune disorders or alteration in immune system development, with the exception of the features described herein.
Abs and immunohistochemistry
All commercial Abs were obtained from BD PharMingen (San Diego, CA) with the exception of anti-CD8 (DAKO, Carpinteria, CA). Anti-clonotypic (Ti98) Ab was used to detect BM3 T cells, as described previously (18). Polyclonal rabbit anti-murine IDO Abs were raised against synthetic peptides (CSAVERQDLKALEKALHD and KPTDGDKSEEPSNVESRGC) encoding amino acid sequences from murine IDO, conjugated to OVA. Serum from immunized rabbits was purified by peptide affinity chromatography. Histological sections (5 µm) were prepared from formalin-fixed paraffin-embedded tissues. Cytocentrifuge preparations of sorted cells were air-dried and fixed in formalin for 10 min. Endogenous peroxidase activity was blocked using hydrogen peroxide (0.3%, 10 min), then tissue sections were treated with proteinase K (10 min; DAKO) followed by Universal Blocking Reagent (8 min; BioGenex, San Ramon, CA), then incubated with anti-IDO Ab (12 h, 1/100 dilution in PBS). Primary Ab was detected with biotinylated goat anti-rabbit secondary (20 min; BioGenex) and peroxidase-conjugated streptavidin, (20 min; BioGenex) with 3-amino-9-ethylcarbazole chromogen, essentially as described for anti-human IDO Ab (10). Controls for specificity included use of preimmune rabbit serum as primary Ab, preincubation of primary Ab with neutralizing peptide (1.2 µg of Ab/10 µg of peptide), and tissues from IDO-deficient mice stained with anti-IDO Ab.
CTLA4-Ig
CTLA4-Ig (cytolytic isoform with an IgG2a Fc domain) was obtained from Chimerigen (catalog no. 70201; Allston, MA,) or Sigma-Aldrich (catalog no. C4483; St. Louis MO).
Flow cytometry
Flow cytometric analyses were performed on cells stained with fluorochrome-conjugated mAbs (BD PharMingen or DAKO) using on FACSCalibur machine (BD Biosciences, Mountain View, CA). Preparative cell sorting was performed using a Mo-Flo four-way flow cytometer (Cytomation; DAKO) equipped with 488 nm of argon (for FITC, PE, PE-CY5) and 647 nm of krypton (for allophycocyanin) lasers. Cells were gated based on forward and side scatter properties and on marker combinations to select cells of interest.
T cell adoptive transfer
Recipient male mice (6- to 8-wk-old) were injected i.v. with pooled splenocytes (between 0.51.0 x 107) from BM3 male donors (6- to 8-wk-old). After 96 h, single cell suspensions of splenocytes were stained with Ab and subjected to flow cytometric analyses, as described (7, 18). Mice treated with CTLA4-Ig received four i.p. injections as follows: 30, 6 h before (100 µg/injection) and 24, 48 h after (50 µg/injection) BM3 cells were injected (t = 0). Some mice were treated with 1 methyl D,L tryptophan (Sigma-Aldrich) or placebo (Innovative Research, Sarasota, FL) by implanting slow-release polymer pellets impregnated with, or without, IDO inhibitor under the dorsal skin of anesthetized mice 6 h before injecting BM3 cells as described (7). Doses were calculated to release
20 mg/day of 1 methyl D,L tryptophan.
| Results |
|---|
|
|
|---|
To examine the effects of CTLA4-Ig, we prepared tissue sections from spleen of F1(CBA x B6) mice treated with CTLA4-Ig and stained them with a rabbit polyclonal anti-IDO peptide Ab (Fig. 1). Very few cells expressed IDO in spleen from untreated mice (Fig. 1a). Many more IDO+ cells were detected in spleen 24 h after CTLA4-Ig injection (Fig. 1, b and c). Clusters of IDO+ cells, mostly small round mononuclear cells (Fig. 1c), were dispersed throughout splenic red pulp areas, while very few were located in lymphoid follicles. Treatment with isotype-matched IgG2a Abs had no effect on IDO expression (data not shown). Comparable outcomes were obtained with CTLA4-Ig obtained from two suppliers (see Materials and Methods).
|
+B220-) and plasmacytoid (CD11c+B220+CD19-) DC subsets, described previously (3, 19). Fig. 1f shows an example of intense homogenous IDO Ab staining, in this case on sorted plasmacytoid DCs (CD11c+B220+CD19-). By comparison, CD11c-B220-CD19- cells (mostly T cells) sorted in parallel were not stained (Fig. 1e). Intensely stained cells were also present in sorted CD11c+DX5+CD8
+ (uniformly stained) and CD11c+DX5+CD8
- (
60% stained) subsets, corresponding to bitypic NK DCs described previously (5). Collectively, IDO+ cells in these three DC subsets accounted for <50% of total CD11c+ splenocytes in each sort and IDO Ab did not stain CD8
- DCs (CD11c+B220-CD8
-). Other sorted populations stained heterogeneously and/or with lower intensities. Together with outcomes from immunohistochemical staining analyses, these data show that IDO expression was selectively and specifically up-regulated in some DC subsets following exposure to CTLA4-Ig. Alternatively, CTLA4-Ig treatment may have induced influx of IDO+ cells into spleen.
|
To examine the effect of induced IDO on APC functions, we injected H-2Kb-specific CD8+ T cells from TCR transgenic mice (BM3) into recipient mice expressing H-2Kb (F1(CBA x B6)). We selected this system because BM3 T cells clonally expand, differentiate into CTLs and cause extensive immunopathology in recipient spleen following adoptive transfer (7, 17, 18, 20). In addition, BM3 T cells do not require CD28-mediated signals to activate (9, 21), rendering them relatively resistant to costimulatory blockade by CTLA4-Ig. Despite this, clonal expansion of donor BM3 CD8+ T cells expressing clonotypic Ab (Ti98+) following adoptive transfer into F1(CBA x B6) mice was blocked completely (99% inhibition) when recipients were treated with CTLA4-Ig (Fig. 2). Consistent with this, very few CD8+ cells were detected in spleen tissues stained with anti-CD8 Ab (Fig. 1g) and spleens exhibited normal tissue architecture. In stark contrast, CTLA4-Ig treatment of IDO-deficient mice with otherwise identical genetic backgrounds (F1(CBA x B6)) had only marginal inhibitory effects on BM3 T cell clonal expansion (25% inhibition) following adoptive transfer (Fig. 2, a and c), which produced large numbers of CD8+ cells in spleen tissue sections (Fig. 1h), accompanied by massive disruption of normal spleen architecture. The low numbers of donor T cells in these CTLA4-Ig-treated IDO-sufficient recipients were comparable with low numbers present in control CBA (H-2Kb-negative) mice analyzed in parallel (Fig. 2a). The low level of CTLA4-Ig-mediated inhibition observed in IDO-deficient recipients may arise from costimulatory blockade of CD28-dependent, H-2b-specific donor T cells with rearranged endogenous TCR genes (our unpublished data). Thus, the ability of CTLA4-Ig to suppress clonal expansion of H-2Kb-specific CD8+ T cells in this experimental system was almost exclusively IDO-dependent.
|
| Discussion |
|---|
|
|
|---|
Phenotypic analyses revealed that DC subsets induced to express uniformly high amounts of IDO were related to DC subsets previously reported to exhibit immunoregulatory properties in some systems. DCs expressing CD8
, first described by Shortman and colleagues (4), can promote tolerance to peripheral self-Ags and tumor-associated Ags, though they can also promote immunity (4, 13, 22, 23, 24, 25). Isolated splenic CD8
+ DCs express IDO and suppress delayed-type hypersensitivity responses, except when treated with IDO inhibitor (26, 27). We found that 100% of nonplasmacytoid CD8
+ DCs (CD11c+B220-CD8
+) expressed high levels of IDO following CTLA4-Ig treatment in vivo, as did cells corresponding to plasmacytoid DCs. Plasmacytoid DCs have tolerogenic or immunostimulatory potential, depending on conditions and their state of activation or maturation (6, 28). Moreover, plasmacytoid DCs may overlap the CD8
+ DC population when they mature (29). We also detected high levels of IDO expression in bitypic DCs coexpressing DC (CD11c) and NK (DX5) markers, also reported to have regulatory properties (5). Because IDO up-regulation is an obligate mechanism by which CTLA4-Ig exerts most of its immunosuppressive activity in our experimental system, classifying DCs based on IDO up-regulation in response to CTLA4-Ig exposure in vivo provides a potential mechanistic explanation for their regulatory effects.
The consequences of up-regulating IDO in minor CD11c+ DC subsets were profound in the BM3 adoptive transfer system, which leads to massive, sublethal destruction of splenic tissues mediated by cytolytic donor CD8+ T cells after 34 days (7, 17, 18, 20). Indeed, sublethal irradiation of recipient mice leads to lethal T cell-mediated graft-vs-host disease. Prior treatment with CTLA4-Ig completely abrogated BM3 T cell clonal expansion, but only if recipients had intact IDO genes. Pharmacologic inhibition of IDO activity only partially restored BM3 T cell clonal expansion, possibly due to low inhibitor bioavailability in vivo (our unpublished data). Thus, CTLA4-Ig mediated costimulatory blockade did not block BM3 clonal expansion, while up-regulated IDO expression had potent inhibitory effects on elicited T cell responses. These outcomes provide mechanistic evidence extending recent findings that CTLA4-Ig-mediated inhibition of pancreatic islet allograft rejection was abrogated in mice treated with pharmacologic IDO inhibitor (16).
IDO-deficient mice exhibit otherwise normal immune system development and function and do not display spontaneous autoimmunity (our unpublished results). This suggests that IDO-mediated suppression is not essential for maintenance of central or peripheral tolerance to self-Ags under homeostatic conditions. The inability of IDO-deficient mice to suppress potentially lethal T cell responses when pretreated with CTLA4-Ig revealed a defect in acquired tolerance. Hence, induced IDO expression may contribute to acquisition of tolerance to neoantigens (30). This implies that therapies based on the use of autologous isolated IDO+ DCs or selective up-regulation of IDO expression in some DC subsets may improve clinical outcomes for patients with autoimmune diseases or following tissue transplantation. Viewed from this perspective, the documented ability of tumors (10, 31) and pathogens, such as HIV (32, 33, 34) to recruit IDO+ DCs and up-regulate IDO expression suggests that the IDO mechanism may contribute to both beneficial and pathologic immunosuppressive pathways (30).
| Acknowledgments |
|---|
| Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Andrew L. Mellor, Program in Molecular Immunology, Institute for Molecular Medicine and Genetics, Medical College of Georgia, 1120 15th Street, Building CA-2006, Augusta, GA 30912. E-mail address: amellor{at}mail.mcg.edu ![]()
3 Abbreviations used in this paper: DC, dendritic cell; IDO, indoleamine 2,3 dioxygenase; 1mT, 1-methyl-tryptophan. ![]()
Received for publication May 12, 2003. Accepted for publication June 25, 2003.
| References |
|---|
|
|
|---|
+ dendritic cell is responsible for inducing peripheral self-tolerance to tissue-associated antigens. J. Exp. Med. 196:1099.
+ dendritic cells expressing indoleamine 2,3-dioxygenase. J. Immunol. 167:708.
globin gene promoters. Int. Immunol. 6:277.
+ dendritic cells. Int. Immunol. 14:65.
in the innate resistance to infection with Chlamydia pneumoniae. J. Immunol. 164:4812.
-induced indoleamine 2,3 dioxygenase and inducible nitric oxide synthase in the replication of human cytomegalovirus in retinal pigment epithelial cells. J. Immunol. 162:957.This article has been cited by other articles:
![]() |
F. Qian, J. Villella, P. K. Wallace, P. Mhawech-Fauceglia, J. D. Tario Jr., C. Andrews, J. Matsuzaki, D. Valmori, M. Ayyoub, P. J. Frederick, et al. Efficacy of Levo-1-Methyl Tryptophan and Dextro-1-Methyl Tryptophan in Reversing Indoleamine-2,3-Dioxygenase-Mediated Arrest of T-Cell Proliferation in Human Epithelial Ovarian Cancer Cancer Res., July 1, 2009; 69(13): 5498 - 5504. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. R. Guerin, J. R. Prins, and S. A. Robertson Regulatory T-cells and immune tolerance in pregnancy: a new target for infertility treatment? Hum. Reprod. Update, March 11, 2009; (2009) dmp004v1. [Abstract] [Full Text] [PDF] |
||||
![]() |
M.-C. Yen, C.-C. Lin, Y.-L. Chen, S.-S. Huang, H.-J. Yang, C.-P. Chang, H.-Y. Lei, and M.-D. Lai A Novel Cancer Therapy by Skin Delivery of Indoleamine 2,3-Dioxygenase siRNA Clin. Cancer Res., January 15, 2009; 15(2): 641 - 649. [Abstract] [Full Text] [PDF] |
||||
![]() |
A W Thomson and P D Robbins Tolerogenic dendritic cells for autoimmune disease and transplantation Ann Rheum Dis, December 1, 2008; 67(Suppl_3): iii90 - iii96. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Calderon, A. Suri, X. O. Pan, J. C. Mills, and E. R. Unanue IFN-{gamma}-Dependent Regulatory Circuits in Immune Inflammation Highlighted in Diabetes J. Immunol., November 15, 2008; 181(10): 6964 - 6974. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. Chen, X. Liang, A. J. Peterson, D. H. Munn, and B. R. Blazar The Indoleamine 2,3-Dioxygenase Pathway Is Essential for Human Plasmacytoid Dendritic Cell-Induced Adaptive T Regulatory Cell Generation J. Immunol., October 15, 2008; 181(8): 5396 - 5404. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Bourquin, D. Anz, K. Zwiorek, A.-L. Lanz, S. Fuchs, S. Weigel, C. Wurzenberger, P. von der Borch, M. Golic, S. Moder, et al. Targeting CpG Oligonucleotides to the Lymph Node by Nanoparticles Elicits Efficient Antitumoral Immunity J. Immunol., September 1, 2008; 181(5): 2990 - 2998. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Harrington, C. V. Srikanth, R. Antony, S. J. Rhee, A. L. Mellor, H. N. Shi, and B. J. Cherayil Deficiency of Indoleamine 2,3-Dioxygenase Enhances Commensal-Induced Antibody Responses and Protects against Citrobacter rodentium-Induced Colitis Infect. Immun., July 1, 2008; 76(7): 3045 - 3053. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Mohib, S. Wang, Q. Guan, A. L. Mellor, H. Sun, C. Du, and A. M. Jevnikar Indoleamine 2,3-dioxygenase expression promotes renal ischemia-reperfusion injury Am J Physiol Renal Physiol, July 1, 2008; 295(1): F226 - F234. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. Fujiwara, B. Wei, L. L. Presley, S. Brewer, M. McPherson, M. A. Lewinski, J. Borneman, and J. Braun Systemic Control of Plasmacytoid Dendritic Cells by CD8+ T Cells and Commensal Microbiota J. Immunol., May 1, 2008; 180(9): 5843 - 5852. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Wan, M. A. Versnel, L. M. E. Leijten, C. G. van Helden-Meeuwsen, D. Fekkes, P. J. M. Leenen, N. A. Khan, R. Benner, and R. C. M. Kiekens Chorionic gonadotropin induces dendritic cells to express a tolerogenic phenotype J. Leukoc. Biol., April 1, 2008; 83(4): 894 - 901. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K. Jasperson, C. Bucher, A. Panoskaltsis-Mortari, P. A. Taylor, A. L. Mellor, D. H. Munn, and B. R. Blazar Indoleamine 2,3-dioxygenase is a critical regulator of acute graft-versus-host disease lethality Blood, March 15, 2008; 111(6): 3257 - 3265. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. H. Cook, A. A. Bickerstaff, J.-J. Wang, T. Nadasdy, P. Della Pelle, R. B. Colvin, and C. G. Orosz Spontaneous Renal Allograft Acceptance Associated with "Regulatory" Dendritic Cells and IDO J. Immunol., March 1, 2008; 180(5): 3103 - 3112. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. L. Humphreys, L. Li, X. Li, D. M. Janowicz, K. R. Fortney, Q. Zhao, W. Li, J. McClintick, B. P. Katz, D. S. Wilkes, et al. Dysregulated Immune Profiles for Skin and Dendritic Cells Are Associated with Increased Host Susceptibility to Haemophilus ducreyi Infection in Human Volunteers Infect. Immun., December 1, 2007; 75(12): 5686 - 5697. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Orbach, J. Rachmilewitz, M. Parnas, J.-H. Huang, M. L. Tykocinski, and M. Dranitzki-Elhalel CTLA-4 {middle dot} FasL Induces Early Apoptosis of Activated T Cells by Interfering with Anti-Apoptotic Signals J. Immunol., December 1, 2007; 179(11): 7287 - 7294. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Saxena, J. K. Ondr, A. F. Magnusen, D. H. Munn, and J. D. Katz The Countervailing Actions of Myeloid and Plasmacytoid Dendritic Cells Control Autoimmune Diabetes in the Nonobese Diabetic Mouse J. Immunol., October 15, 2007; 179(8): 5041 - 5053. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. John and P. J. Nelson Dendritic Cells in the Kidney J. Am. Soc. Nephrol., October 1, 2007; 18(10): 2628 - 2635. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. W. Tas, M. J. Vervoordeldonk, N. Hajji, J. H. N. Schuitemaker, K. F. van der Sluijs, M. J. May, S. Ghosh, M. L. Kapsenberg, P. P. Tak, and E. C. de Jong Noncanonical NF-{kappa}B signaling in dendritic cells is required for indoleamine 2,3-dioxygenase (IDO) induction and immune regulation Blood, September 1, 2007; 110(5): 1540 - 1549. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Rey-Ladino, X. Jiang, B. R. Gabel, C. Shen, and R. C. Brunham Survival of Chlamydia muridarum within Dendritic Cells Infect. Immun., August 1, 2007; 75(8): 3707 - 3714. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. P. J. van der Marel, J. N. Samsom, M. Greuter, L. A. van Berkel, T. O'Toole, G. Kraal, and R. E. Mebius Blockade of IDO Inhibits Nasal Tolerance Induction J. Immunol., July 15, 2007; 179(2): 894 - 900. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. F. May Jr., X. Chang, H. Zhang, K. D. Lute, P. Zhou, E. Kocak, P. Zheng, and Y. Liu B7-Deficient Autoreactive T Cells Are Highly Susceptible to Suppression by CD4+CD25+ Regulatory T Cells J. Immunol., February 1, 2007; 178(3): 1542 - 1552. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Zhu, F. Ji, Y. Wang, Y. Zhang, Q. Liu, J. Z. Zhang, K. Matsushima, Q. Cao, and Y. Zhang Synovial Autoreactive T Cells in Rheumatoid Arthritis Resist IDO-Mediated Inhibition J. Immunol., December 1, 2006; 177(11): 8226 - 8233. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Agaugue, L. Perrin-Cocon, F. Coutant, P. Andre, and V. Lotteau 1-Methyl-Tryptophan Can Interfere with TLR Signaling in Dendritic Cells Independently of IDO Activity J. Immunol., August 15, 2006; 177(4): 2061 - 2071. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. L. Belladonna, U. Grohmann, P. Guidetti, C. Volpi, R. Bianchi, M. C. Fioretti, R. Schwarcz, F. Fallarino, and P. Puccetti Kynurenine Pathway Enzymes in Dendritic Cells Initiate Tolerogenesis in the Absence of Functional IDO J. Immunol., July 1, 2006; 177(1): 130 - 137. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Rutella, G. Bonanno, A. Procoli, A. Mariotti, D. G. de Ritis, A. Curti, S. Danese, G. Pessina, S. Pandolfi, F. Natoni, et al. Hepatocyte growth factor favors monocyte differentiation into regulatory interleukin (IL)-10++IL-12low/neg accessory cells with dendritic-cell features Blood, July 1, 2006; 108(1): 218 - 227. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Benigni, S. Tomasoni, L. A. Turka, L. Longaretti, L. Zentilin, M. Mister, A. Pezzotta, N. Azzollini, M. Noris, S. Conti, et al. Adeno-Associated Virus-Mediated CTLA4Ig Gene Transfer Protects MHC-Mismatched Renal Allografts from Chronic Rejection J. Am. Soc. Nephrol., June 1, 2006; 17(6): 1665 - 1672. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. J. O'Connell, X. Wang, M. Leon-Ponte, C. Griffiths, S. C. Pingle, and G. P. Ahern A novel form of immune signaling revealed by transmission of the inflammatory mediator serotonin between dendritic cells and T cells Blood, February 1, 2006; 107(3): 1010 - 1017. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Roshick, H. Wood, H. D. Caldwell, and G. McClarty Comparison of Gamma Interferon-Mediated Antichlamydial Defense Mechanisms in Human and Mouse Cells Infect. Immun., January 1, 2006; 74(1): 225 - 238. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Harnaha, J. Machen, M. Wright, R. Lakomy, A. Styche, M. Trucco, S. Makaroun, and N. Giannoukakis Interleukin-7 Is a Survival Factor for CD4+ CD25+ T-Cells and Is Expressed by Diabetes-Suppressive Dendritic Cells Diabetes, January 1, 2006; 55(1): 158 - 170. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Marski, S. Kandula, J. R. Turner, and C. Abraham CD18 Is Required for Optimal Development and Function of CD4+CD25+ T Regulatory Cells J. Immunol., December 15, 2005; 175(12): 7889 - 7897. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. J. M. van Oosterhout and N. Bloksma Regulatory T-lymphocytes in asthma Eur. Respir. J., November 1, 2005; 26(5): 918 - 932. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. L. Mellor, B. Baban, P. R. Chandler, A. Manlapat, D. J. Kahler, and D. H. Munn Cutting Edge: CpG Oligonucleotides Induce Splenic CD19+ Dendritic Cells to Acquire Potent Indoleamine 2,3-Dioxygenase-Dependent T Cell Regulatory Functions via IFN Type 1 Signaling J. Immunol., November 1, 2005; 175(9): 5601 - 5605. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Fallarino, C. Orabona, C. Vacca, R. Bianchi, S. Gizzi, C. Asselin-Paturel, M. C. Fioretti, G. Trinchieri, U. Grohmann, and P. Puccetti Ligand and cytokine dependence of the immunosuppressive pathway of tryptophan catabolism in plasmacytoid dendritic cells Int. Immunol., November 1, 2005; 17(11): 1429 - 1438. [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] |
||||
![]() |
J. Tsukada, A. Ozaki, T. Hanada, T. Chinen, R. Abe, A. Yoshimura, and M. Kubo The role of suppressor of cytokine signaling 1 as a negative regulator for aberrant expansion of CD8{alpha}+ dendritic cell subset Int. Immunol., September 1, 2005; 17(9): 1167 - 1178. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Datta, M. L. deSchoolmeester, C. Hedeler, N. W. Paton, A. M. Brass, and K. J. Else Identification of Novel Genes in Intestinal Tissue That Are Regulated after Infection with an Intestinal Nematode Parasite Infect. Immun., July 1, 2005; 73(7): 4025 - 4033. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Baban, A. M. Hansen, P. R. Chandler, A. Manlapat, A. Bingaman, D. J. Kahler, D. H. Munn, and A. L. Mellor A minor population of splenic dendritic cells expressing CD19 mediates IDO-dependent T cell suppression via type I IFN signaling following B7 ligation Int. Immunol., July 1, 2005; 17(7): 909 - 919. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Orabona, M. L. Belladonna, C. Vacca, R. Bianchi, F. Fallarino, C. Volpi, S. Gizzi, M. C. Fioretti, U. Grohmann, and P. Puccetti Cutting Edge: Silencing Suppressor of Cytokine Signaling 3 Expression in Dendritic Cells Turns CD28-Ig from Immune Adjuvant to Suppressant J. Immunol., June 1, 2005; 174(11): 6582 - 6586. [Abstract] [Full Text] [PDF] |
||||
![]() |
U. Hainz, P. Obexer, C. Winkler, P. Sedlmayr, O. Takikawa, H. Greinix, A. Lawitschka, U. Putschger, D. Fuchs, S. Ladisch, et al. Monocyte-mediated T-cell suppression and augmented monocyte tryptophan catabolism after human hematopoietic stem-cell transplantation Blood, May 15, 2005; 105(10): 4127 - 4134. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Boasso, J.-P. Herbeuval, A. W. Hardy, C. Winkler, and G. M. Shearer Regulation of indoleamine 2,3-dioxygenase and tryptophanyl-tRNA-synthetase by CTLA-4-Fc in human CD4+ T cells Blood, February 15, 2005; 105(4): 1574 - 1581. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-M. Huang, X. Liu, K. Steffensen, A. Sanna, G. Arru, M. L. Fois, G. Rosati, S. Sotgiu, and H. Link Immunological heterogeneity of multiple sclerosis in Sardinia and Sweden Multiple Sclerosis, February 1, 2005; 11(1): 16 - 23. [Abstract] [PDF] |
||||
![]() |
X.-Y. Zhu, Y.-H. Zhou, M.-Y. Wang, L.-P. Jin, M.-M. Yuan, and D.-J. Li Blockade of CD86 Signaling Facilitates a Th2 Bias at the Maternal-Fetal Interface and Expands Peripheral CD4+CD25+ Regulatory T Cells to Rescue Abortion-Prone Fetuses Biol Reprod, February 1, 2005; 72(2): 338 - 345. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. W. O'Neill, S. Adams, and N. Bhardwaj Manipulating dendritic cell biology for the active immunotherapy of cancer Blood, October 15, 2004; 104(8): 2235 - 2246. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. L. Mellor, P. Chandler, B. Baban, A. M. Hansen, B. Marshall, J. Pihkala, H. Waldmann, S. Cobbold, E. Adams, and D. H. Munn Specific subsets of murine dendritic cells acquire potent T cell regulatory functions following CTLA4-mediated induction of indoleamine 2,3 dioxygenase Int. Immunol., October 1, 2004; 16(10): 1391 - 1401. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Fallarino, C. Asselin-Paturel, C. Vacca, R. Bianchi, S. Gizzi, M. C. Fioretti, G. Trinchieri, U. Grohmann, and P. Puccetti Murine Plasmacytoid Dendritic Cells Initiate the Immunosuppressive Pathway of Tryptophan Catabolism in Response to CD200 Receptor Engagement J. Immunol., September 15, 2004; 173(6): 3748 - 3754. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Waldmann and S. Cobbold Exploiting Tolerance Processes in Transplantation Science, July 9, 2004; 305(5681): 209 - 212. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Mirenda, I. Berton, J. Read, T. Cook, J. Smith, A. Dorling, and R. I. Lechler Modified Dendritic Cells Coexpressing Self and Allogeneic Major Histocompatability Complex Molecules: An Efficient Way to Induce Indirect Pathway Regulation J. Am. Soc. Nephrol., April 1, 2004; 15(4): 987 - 997. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. H. Munn, M. D. Sharma, and A. L. Mellor Ligation of B7-1/B7-2 by Human CD4+ T Cells Triggers Indoleamine 2,3-Dioxygenase Activity in Dendritic Cells J. Immunol., April 1, 2004; 172(7): 4100 - 4110. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. A. Swanson, Y. Zheng, K. M. Heidler, T. Mizobuchi, and D. S. Wilkes CDllc+ Cells Modulate Pulmonary Immune Responses by Production of Indoleamine 2,3-Dioxygenase Am. J. Respir. Cell Mol. Biol., March 1, 2004; 30(3): 311 - 318. [Abstract] [Full Text] [PDF] |
||||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |