|
|
||||||||
CUTTING EDGE |
-Chain Is an Indispensable Subunit of the IL-21 Receptor Complex1





*
Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, Sendai, Japan;
Department of Pediatric Oncology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan;
Department of Functional Cloning, ZymoGenetics, Seattle, WA 98102; and
Core Research for Evolutional Science and Technology of the Japan Science and Technology Corporation, Tokyo, Japan
| Abstract |
|---|
|
|
|---|
-chain (
c) is an
indispensable subunit of the functional receptor complexes for IL-4,
IL-7, IL-9, and IL-15 as well as IL-2. Here we show that the
c is also shared with the IL-21R complex. Although IL-21
binds to the IL-21R expressed on
c-deficient
ED40515- cells, IL-21 is unable to transduce any
intracytoplasmic signals. However, in ED
-16 cells, a
c-transfected ED40515- cell line, IL-21
binds to the IL-21R and can activate Janus kinase (JAK)1, JAK3, STAT1,
and STAT3. The chemical cross-linking study reveals the direct binding
of IL-21 to the
c. These data clearly demonstrate that
the
c is an indispensable subunit of the functional
IL-21R complex. | Introduction |
|---|
|
|
|---|
-chain, which was
originally identified as a GM-CSF receptor
-chain, is shared with
IL-3 and IL-5 (1). Glycoprotein 130, which was originally
discovered as a component of the IL-6R complex, is shared with IL-11,
oncostatin M, LIF, ciliary neurotrophic factor, and cardiotrophin-1
(2). We previously reported the cloning of an IL-2R
-chain and demonstrated it to be an essential component for the
functional IL-2R complex (3, 4). The IL-2R
-chain was
later uncovered to be an indispensable subunit of the IL-4, IL-7, IL-9,
and IL-15 receptors and is now referred to as the common
-chain
(
c)3
(5). The human
c gene is located on the X
chromosome, and patients with X-linked SCID (XSCID), a disease
characterized by an absence of T and NK cells with a presence of
nonfunctional B cells, have mutations in the
c gene
(6, 7). The mutant
cs detected in the XSCID
patients were revealed to have no ability for formation of the
functional receptor complexes (8). Furthermore,
c gene-targeting mice demonstrated that various
phenotypes of XSCID patients are caused by the dysfunction of the
c (9, 10, 11). These findings raised the next
question of which cytokines are responsible for each hemopoietic cell
development disturbed in XSCID patients. Gene disruption of either IL-7
or the IL-7R
-chain led to severe developmental defects of T and B
cells (12, 13). Therefore, IL-7 was thought to be an
essential cytokine for T and B cell differentiation and proliferation
in mice. Gene disruption of the IL-2R
-chain as well as the
c but not of IL-2, led to a defect of NK cell
development (14, 15). Because the IL-15R complex is
composed of the IL-2R
-chain and the
c in addition to
the unique IL-15R
-chain, dysfunction of IL-15 seems to lead to
a severe defect of NK cells (16, 17). However, the
functional roles of the
c are still not fully
understood.
Recently a novel cytokine, IL-21 and its receptor were identified
(18, 19). Interestingly, structural similarities between
IL-21 and IL-2, IL-4, and IL-15 and between the IL-21R and the IL-2R
-chain and the IL-4R
-chain are shown. These findings led us to
speculate that IL-21 also shares the
c as a functional
subunit of its IL-21R complex. In this paper we clearly demonstrate
that the
c is an indispensable component of the
functional IL-21R as well as receptors for IL-2, IL-4, IL-7, IL-9, and
IL-15.
| Materials and Methods |
|---|
|
|
|---|
Cells used in this paper were of the human T cell leukemia
virus-I-transformed human T cell line ED40515-
(20), which lacks expression of
c, and
ED40515--derived transfectants, ED
-15,
ED
-16, EDtSH
-4, and ED-AV-7R.cl2 as reported previously (8, 21, 22). ED
-15 and ED
-16 cells express wild-type human
c. EDtSH
-4 and ED-AV-7R.cl2 cells express a mutant
c deleted of C-terminal 50 aa and a mutant
c with one amino acid substitution at the extracellular
region (from Ala156 to Val), respectively; both
of them were derived from XSCID patients. These cell lines were
maintained in RPMI 1640 medium supplemented with 10% FBS, 2 mM
L-glutamine, penicillin, and streptomycin.
An anti-human IL-2R
-chain mAb (TUGh4) was described previously
(23). Anti-Janus kinase (JAK)1, -JAK2, -JAK3, -Tyk2,
-STAT1, -STAT3, and -STAT5 polyclonal Abs were purchased
from Santa Cruz Biotechnology (Santa Cruz, CA). Phosphospecific
polyclonal Abs, anti-phospho-STAT1 (Y701), -STAT3 (Y705), and -STAT5
(Y694), and P-Tyr-100, which is an anti-phosphotyrosine monoclonal
Ab, were purchased from Cell Signaling Technology (Beverly, MA).
HRP-labeled anti-mouse IgG and HRP-labeled anti-rabbit IgG Abs
used as secondary Abs were purchased from KPL (Gaithersburg,
MD).
Immunofluorescence staining and binding of IL-21 to
ED40515- and ED
-16 cells
Immunofluorescence staining of cells with biotin-conjugated TUGh4 was conducted as described previously (8). Recombinant human IL-21 was conjugated to N-hydroxysulfosuccinimide-long chain-biotin (Pierce, Rockford, IL). Cells were incubated with 100 ng/ml biotin-conjugated IL-21 for 60 min at 4°C. After washing, the cells were incubated with streptavidin-PE (BD Biosciences, San Jose, CA) for 20 min at 4°C to be visualized. The cells were then subjected to a flow cytometer (FACSCalibur; BD Immunocytometry Systems, Mountain View, CA). Incubation with 2 µg/ml unlabeled IL-21 before the addition of the biotinylated IL-21 provided the background control staining.
Immunoprecipitation and immunoblot assay
Immunoprecipitation and immunoblot assay were described previously (22, 24). Cells were stimulated with 10 ng/ml IL-21 or 1 nM IL-2 for 10 min for immunoprecipitation of the JAKs and for 30 and 60 min for phosphospecific immunoblot assay of the STATs.
EMSA
EMSA was conducted as described previously (24).
Double-stranded 32P-labeled M67-SIE sequence
(5'-GTGCATTTCCCGTAAATCTTGTCTACAATTC-3') and
-casein-SIE
sequence (5'-TGTGGACTTCTTGGAAT TAAGGGACTTTTG-3') were used as probes
for STAT1/3 and STAT5, respectively.
Cross-linking experiment
Cells were incubated with 100 ng/ml of biotinylated IL-21 or IL-2 for 1 h on ice. Cells were washed with ice-cold PBS and then suspended in ice-cold cross-linking buffer (1 mM MgCl2-PBS pH 8.3). Disuccinimidyl suberate (DSS; Pierce) was added at a concentration of 100 µg/ml followed by another 30-min incubation on ice. Cells were harvested and lysed for immunoprecipitation as described above. HRP-conjugated streptavidin (Amersham Pharmacia Biotech, Little Chalfont, U.K.) was used for the detection of biotinylated IL-21 or IL-2.
| Results and Discussion |
|---|
|
|
|---|
c
To investigate the possible involvement of
c in
formation of the IL-21R complex, we first tested IL-21R expression on
the ED40515- cell line, which is reportedly
defective for
c expression on cell surfaces
(20). We conducted flow cytometry on this cell line using
biotinylated human IL-21. ED40515- cells and
also ED
-16 cells, which stably express the exogenous wild-type
c, bind IL-21 (Fig. 1
, bottom). The specificity of biotinylated IL-21
binding to its receptor was controlled by a blocking experiment with an
excess of unlabeled IL-21. These results suggested that IL-21 can bind
to its receptor without
c. RT-PCR showed the expression
of IL-21R mRNA in the ED40515- cell line (data
not shown). The expression of
c on each cell line is
shown (Fig. 1
, top).
|
c
Next, we examined whether IL-21 requires
c for its
intracellular signal transduction. All the cytokines whose receptors
belong to the cytokine receptor family induce activation of JAKs with
various combinations among the JAK family tyrosine kinases. The IL-21R
and the
c were reported to associate with JAK1 and JAK3,
respectively (19, 21, 25, 26, 27). Hence, we examined tyrosine
phosphorylation of the JAKs as a result of their
activation. We immunoprecipitated JAK1, JAK2, JAK3, and Tyk2 before
and after IL-21 or IL-2 stimulation and then immunoblotted with
P-Tyr-100. IL-21 as well as IL-2 apparently induced
phosphorylation of JAK1 in ED
-16 cells but not in
ED40515- cells (Fig. 2
A).
Phosphorylation of JAK3 was detectable in these cell
lines even before stimulation, and was significantly enhanced in
ED
-16 cells after stimulation with either IL-21 or IL-2 (Fig. 2
B). Similar results were obtained in ED
-15, which is
another cell line expressing the exogenous wild-type
c
(data not shown). These data clearly demonstrate that IL-21 absolutely
requires the
c for its signal transduction. The
constitutive tyrosine phosphorylation of JAK3 was
previously reported with other human T cell leukemia virus-I-infected
cell lines (28). Phosphorylation of Tyk2
was undetectable, and we detected weak phosphorylation
of JAK2 in ED
-16 cells upon stimulation with either IL-21 or IL-2.
Because the expression level of JAK2 was quite low, the weak bands may
reflect physiologically significant activation of JAK2.
|
-16 cells but not in
ED40515- cells
STATs are also phosphorylated and activated for their
transcriptional activities upon cytokine stimulation (29).
Hence, we examined IL-21-mediated phosphorylation of
STAT1, STAT3, and STAT5 with ED
-16 and
ED40515- cells. The cells were stimulated with
IL-21, and their extracts were then immunoblotted with Abs specific for
tyrosine-phosphorylated STAT1, STAT3, and STAT5. IL-21 as
well as IL-2 clearly induced tyrosine phosphorylation
of STAT1 in ED
-16 cells but not in ED40515-
cells (Fig. 3
A).
Phosphorylation of STAT3 was detectable in these cell
lines even before stimulation, and was significantly enhanced in
ED
-16 cells after stimulation with either IL-21 or IL-2 (Fig. 3
B). Although IL-2 induced significant tyrosine
phosphorylation of STAT5, IL-21 produced a weak
phosphorylation of STAT5 (Fig. 3
C). A high
concentration of IL-21 (100 ng/ml) was not able to enhance the
phosphorylation of STAT5 (data not shown). To
confirm these results, we conducted EMSA with the ED
-16 cell
extracts. Both IL-2 and IL-21 activated STAT1 activity. The DNA
binding activity of STAT3 was observed without stimulation; however,
upon IL-2 AND IL-21 stimulation, the binding activity was increased
(Fig. 3
D). Whereas IL-2 activated STAT5, IL-21 induced a
weak activation of STAT5. The specificity of the bands for the STATs
was verified with supershift assays using specific Abs. In the presence
of anti-STAT1, -STAT3, or -STAT5, the bands almost disappeared,
respectively, and formed supershifted bands in the cases of
anti-STAT3 and -STAT5. These results were consistent with those of
immunoblots using phosphotyrosine-specific Abs. Homodimerization of the
IL-21R is reported to activate STAT5 but not STAT3 (19).
This observation seems inconsistent with our present results. Although
the IL-21R was reported to have a consensus motif for STAT3 binding in
its C-terminal tail (18), it is not clear which tyrosine
residue is responsible for the activation of STAT5. Further study will
need to identify critical regions for the activation of each
STAT.
|
c mutants for their signal-transducing
activities as a component of the IL-21R complex. We used tSH and
AV mutants of the
c, which were derived from
XSCID patients whose phenotypes were a typical and a NK-positive
atypical XSCID, respectively (8, 22). tSH mutant lacks
C-terminal 50 aa with a result of frame shift mutation, and we reported
previously that tSH mutant had no function on IL-2-induced signal
transduction (8). As expected, tSH mutant also had no
function on IL-21-induced STAT activation. In contrast, AV mutant has
an amino acid substitution, Ala156 to Val on the
extracellular domain of
c (8). We reported
that AV mutant expressing ED40515- subline,
ED-AV-7R.cl2, was selectively impaired in their responses to IL-4 or
IL-7, although responses to IL-2 or IL-15 were relatively maintained
(22). IL-21-induced STAT3 activation through AV mutant
c was comparable with wild-type
c,
however, activation of STAT1 was impaired. These results suggest that
IL-21 as well as IL-2 require both of the extracellular and
intracytoplasmic regions of the
c for the signal
transduction.
Sharing of the
c with the IL-21R complex
IL-21 was revealed to bind to ED40515-
cells negative for
c expression (Fig. 1
), suggesting the
dispensability of the
c for IL-21 binding. However,
because the
c was found to be required for the IL-21
signaling, we speculated that the
c is an effector
subunit of the IL-21R complex. To examine this possibility, we
attempted to detect IL-21 in the
c receptor complex.
ED40515- and ED
-16 cells were incubated with
biotinylated IL-21 or biotinylated IL-2 and cross-linked with a
chemical cross-linker (DSS). Their lysates were immunoprecipitated with
anti-
c mAb (TUGh4). The immunoprecipitates were then
separated with SDS-PAGE and transferred to a membrane, followed by
detection with HRP-labeled-streptavidin. Fig. 4
shows
biotinylated-IL-21-
c complex
85 kDa in ED
-16 cells
but not in ED40515- cells. This molecular size
is comparable with that of
c (6470 kDa) plus IL-21 (15
kDa). Similar results were obtained with biotinylated IL-2. These
results suggest that the IL-21R complex contains the
c
as an essential component like the IL-2R complex. In this paper, we
clearly demonstrated that
c is an indispensable receptor
subunit for IL-21 as well as IL-2, IL-4, IL-7, IL-9, and IL-15.
|
| Acknowledgments |
|---|
| Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Hironobu Asao, Department of Microbiology and Immunology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575 Japan. E-mail address: asao-h{at}mail.cc.tohoku.ac.jp ![]()
3 Abbreviations used in this paper:
c, common
-chain; JAK, Janus kinase; XSCID, X-linked SCID; DSS, disuccinimidyl suberate. ![]()
Received for publication March 27, 2001. Accepted for publication May 3, 2001.
| References |
|---|
|
|
|---|
chain of the human IL-2 receptor. Science 257:379.
chain in two distinct signaling pathways. Proc. Natl. Acad. Sci. USA 90:4127.
-chain for multiple cytokine receptors. Adv. Immunol. 59:225.[Medline]
chain mutation results in X-linked severe combined immunodeficiency in humans. Cell 73:147.[Medline]
chain: its role in the multiple cytokine receptor complexes and T cell development in XSCID. Annu. Rev. Immunol. 14:179.[Medline]
-chains in patients with X-linked severe combined immunodeficiency. J. Immunol. 153:1310.[Abstract]
chain. Proc. Natl. Acad. Sci. USA 92:377.
chain. Immunity 2:223.[Medline]
chain. Blood 87:956.
chain. J. Exp. Med. 185:499.
chain of the IL-2 receptor. EMBO J. 14:3654.[Medline]
chain and close linkage of IL15RA and IL2RA genes. J. Biol. Chem. 270:29862.
chain. Proc. Natl. Acad. Sci. USA 97:11439.
chain on various populations in human peripheral blood. Int. Immunol. 6:1273.
has dual potentials in inhibiting or promoting cell proliferation. J. Biol. Chem. 275:867.
c chain of the IL-2 receptor. Science 266:1039.
and
c chains with Jak1 and Jak3: implications for XSCID and XCID. Science 266:1042.This article has been cited by other articles:
![]() |
D Fina, M Sarra, R Caruso, G Del Vecchio Blanco, F Pallone, T T MacDonald, and G Monteleone Interleukin 21 contributes to the mucosal T helper cell type 1 response in coeliac disease Gut, July 1, 2008; 57(7): 887 - 892. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. R. Simpson-Abelson, G. F. Sonnenberg, H. Takita, S. J. Yokota, T. F. Conway Jr., R. J. Kelleher Jr., L. D. Shultz, M. Barcos, and R. B. Bankert Long-Term Engraftment and Expansion of Tumor-Derived Memory T Cells Following the Implantation of Non-Disrupted Pieces of Human Lung Tumor into NOD-scid IL2R{gamma}null Mice J. Immunol., May 15, 2008; 180(10): 7009 - 7018. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Xing, C. J. Cardona, J. Li, N. Dao, T. Tran, and J. Andrada Modulation of the immune responses in chickens by low-pathogenicity avian influenza virus H9N2 J. Gen. Virol., May 1, 2008; 89(5): 1288 - 1299. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. A. Scheeren, S. A. Diehl, L. A. Smit, T. Beaumont, M. Naspetti, R. J. Bende, B. Blom, K. Karube, K. Ohshima, C. J. M. van Noesel, et al. IL-21 is expressed in Hodgkin lymphoma and activates STAT5: evidence that activated STAT5 is required for Hodgkin lymphomagenesis Blood, May 1, 2008; 111(9): 4706 - 4715. [Abstract] [Full Text] [PDF] |
||||
![]() |
A H Sawalha, K M Kaufman, J A Kelly, A J Adler, T Aberle, J Kilpatrick, E K Wakeland, Q-Z Li, A E Wandstrat, D R Karp, et al. Genetic association of interleukin-21 polymorphisms with systemic lupus erythematosus Ann Rheum Dis, April 1, 2008; 67(4): 458 - 461. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Caprioli, M. Sarra, R. Caruso, C. Stolfi, D. Fina, G. Sica, T. T. MacDonald, F. Pallone, and G. Monteleone Autocrine Regulation of IL-21 Production in Human T Lymphocytes J. Immunol., February 1, 2008; 180(3): 1800 - 1807. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. de Totero, R. Meazza, M. Capaia, M. Fabbi, B. Azzarone, E. Balleari, M. Gobbi, G. Cutrona, M. Ferrarini, and S. Ferrini The opposite effects of IL-15 and IL-21 on CLL B cells correlate with differential activation of the JAK/STAT and ERK1/2 pathways Blood, January 15, 2008; 111(2): 517 - 524. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Li and C. Yee IL-21 mediated Foxp3 suppression leads to enhanced generation of antigen-specific CD8+ cytotoxic T lymphocytes Blood, January 1, 2008; 111(1): 229 - 235. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. D. Davis, K. Skak, M. J. Smyth, P. E.G. Kristjansen, D. M. Miller, and P. V. Sivakumar Interleukin-21 Signaling: Functions in Cancer and Autoimmunity Clin. Cancer Res., December 1, 2007; 13(23): 6926 - 6932. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Liu, G. Lizee, Y. Lou, C. Liu, W. W. Overwijk, G. Wang, and P. Hwu IL-21 synergizes with IL-7 to augment expansion and anti-tumor function of cytotoxic T cells Int. Immunol., October 1, 2007; 19(10): 1213 - 1221. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Onoda, M. Rahman, H. Nara, A. Araki, K. Makabe, K. Tsumoto, I. Kumagai, T. Kudo, N. Ishii, N. Tanaka, et al. Human CD4+ central and effector memory T cells produce IL-21: effect on cytokine-driven proliferation of CD4+ T cell subsets Int. Immunol., October 1, 2007; 19(10): 1191 - 1199. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. R. Barker, J. G. Parvani, D. Meyer, A. S. Hey, K. Skak, and N. L. Letvin IL-21 Induces Apoptosis of Antigen-Specific CD8+ T Lymphocytes J. Immunol., September 15, 2007; 179(6): 3596 - 3603. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. A. Casey and M. F. Mescher IL-21 Promotes Differentiation of Naive CD8 T Cells to a Unique Effector Phenotype J. Immunol., June 15, 2007; 178(12): 7640 - 7648. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. D. Davis, B. K. Skrumsager, J. Cebon, T. Nicholaou, J. W. Barlow, N. P. H. Moller, K. Skak, D. Lundsgaard, K. S. Frederiksen, P. Thygesen, et al. An Open-Label, Two-Arm, Phase I Trial of Recombinant Human Interleukin-21 in Patients with Metastatic Melanoma Clin. Cancer Res., June 15, 2007; 13(12): 3630 - 3636. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Zeng, R. Spolski, E. Casas, W. Zhu, D. E. Levy, and W. J. Leonard The molecular basis of IL-21-mediated proliferation Blood, May 15, 2007; 109(10): 4135 - 4142. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. White, S. Krishnan, N. Strbo, H. Liu, M. A. Kolber, M. G. Lichtenheld, R. N. Pahwa, and S. Pahwa Differential effects of IL-21 and IL-15 on perforin expression, lysosomal degranulation, and proliferation in CD8 T cells of patients with human immunodeficiency virus-1 (HIV) Blood, May 1, 2007; 109(9): 3873 - 3880. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. M. Coquet, K. Kyparissoudis, D. G. Pellicci, G. Besra, S. P. Berzins, M. J. Smyth, and D. I. Godfrey IL-21 Is Produced by NKT Cells and Modulates NKT Cell Activation and Cytokine Production J. Immunol., March 1, 2007; 178(5): 2827 - 2834. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Frohlich, B. J. Marsland, I. Sonderegger, M. Kurrer, M. R. Hodge, N. L. Harris, and M. Kopf IL-21 receptor signaling is integral to the development of Th2 effector responses in vivo Blood, March 1, 2007; 109(5): 2023 - 2031. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. L. Good, V. L. Bryant, and S. G. Tangye Kinetics of Human B Cell Behavior and Amplification of Proliferative Responses following Stimulation with IL-21 J. Immunol., October 15, 2006; 177(8): 5236 - 5247. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Suto, A. L. Wurster, S. L. Reiner, and M. J. Grusby IL-21 Inhibits IFN-{gamma} Production in Developing Th1 Cells through the Repression of Eomesodermin Expression J. Immunol., September 15, 2006; 177(6): 3721 - 3727. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. H. Goldschmidt, J. S. Kennedy, D. R. Kennedy, H. Yuan, D. E. Holt, M. L. Casal, A. M. Traas, E. A. Mauldin, P. F. Moore, P. S. Henthorn, et al. Severe Papillomavirus Infection Progressing to Metastatic Squamous Cell Carcinoma in Bone Marrow-Transplanted X-Linked SCID Dogs. J. Virol., July 1, 2006; 80(13): 6621 - 6628. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Pelletier and D. Girard Differential Effects of IL-15 and IL-21 in Myeloid (CD11b+) and Lymphoid (CD11b-) Bone Marrow Cells J. Immunol., July 1, 2006; 177(1): 100 - 108. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. M. Roda, R. Parihar, A. Lehman, A. Mani, S. Tridandapani, and W. E. Carson III Interleukin-21 Enhances NK Cell Activation in Response to Antibody-Coated Targets J. Immunol., July 1, 2006; 177(1): 120 - 129. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Strengell, A. Lehtonen, S. Matikainen, and I. Julkunen IL-21 enhances SOCS gene expression and inhibits LPS-induced cytokine production in human monocyte-derived dendritic cells J. Leukoc. Biol., June 1, 2006; 79(6): 1279 - 1285. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. de Totero, R. Meazza, S. Zupo, G. Cutrona, S. Matis, M. Colombo, E. Balleari, I. Pierri, M. Fabbi, M. Capaia, et al. Interleukin-21 receptor (IL-21R) is up-regulated by CD40 triggering and mediates proapoptotic signals in chronic lymphocytic leukemia B cells Blood, May 1, 2006; 107(9): 3708 - 3715. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. J. Burgess, A. I. Marusina, I. Pathmanathan, F. Borrego, and J. E. Coligan IL-21 Down-Regulates NKG2D/DAP10 Expression on Human NK and CD8+ T Cells J. Immunol., February 1, 2006; 176(3): 1490 - 1497. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Comes, O. Rosso, A. M. Orengo, E. Di Carlo, C. Sorrentino, R. Meazza, T. Piazza, B. Valzasina, P. Nanni, M. P. Colombo, et al. CD25+ Regulatory T Cell Depletion Augments Immunotherapy of Micrometastases by an IL-21-Secreting Cellular Vaccine J. Immunol., February 1, 2006; 176(3): 1750 - 1758. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Fornek, L. T. Tygrett, T. J. Waldschmidt, V. Poli, R. C. Rickert, and G. S. Kansas Critical role for Stat3 in T-dependent terminal differentiation of IgG B cells Blood, February 1, 2006; 107(3): 1085 - 1091. [Abstract] [Full Text] [PDF] |
||||
![]() |
|