bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Early Expansion and Maturation of Semi-Invariant NK T Cells Inhibited Autoimmune Pathogenesis in Congenic Nonobese Diabetic Mice
Authors: Ueno Aito , Wang Jianxiong , Cheng Lu , Im Jin S. , Shi Yan , Porcelli Steven A. , Yang Yang
Published: April 2014

Semi-invariant NK T cell (iNKT) deficiency has long been associated with the pathogenesis of type 1 diabetes (T1D), but the linkage between this the deficiency and T1D susceptibility gene(s) remains unclear. We analyzed NOD mice subcongenic for resistant alleles of Idd9 locus in search for protective mechanisms against T1D, and found that iNKT cell development was significantly enhanced with a more advanced mature phenotype and function in mice containing Idd9.1 sublocus of B10 origin. The enhanced iNKT cell development and function suppressed effector function of diabetogenic T cells. Elimination of iNKT cells by CD1d deficiency almost abolished T1D protection in these mice. Interestingly, although the iNKT cells were responsible for a Th2 orientated cytokine profile that is often regarded as a mechanism of T1D prevention, our data suggests that the Th2 bias played little if any role for the protection. In addition, dendritic cells from the congenic NOD mice showed increased abilities to engage and potentiate iNKT cells, suggesting that a mechanism mediated by dendritic cells or other APCs may be critical for the enhanced development and maturation of iNKT cells. The products of T1D susceptibility gene(s) in Idd9.1 locus may be a key factor for this mechanism.
Caspase 6 Regulates B Cell Activation and Differentiation into Plasma Cells
Authors: Watanabe Chie , Shu Geraldine L. , Zheng Timothy S. , Flavell Richard A. , Clark Edward A.
Published: April 2014

Caspase (Casp) family proteases regulate not only lymphocyte apoptosis but also lymphocyte activation and development. In this study, we show that Casp6 regulates B cell activation and differentiation into plasma cells by modifying cell cycle entry. B cells from Casp6 knockout (Casp6 KO) mice examined ex vivo have more cells in G1 than wild-type B cells, and mitogen-induced G1 entry of Casp6 KO B cells is much faster than that of wild-type B cells. Even so, S phase entry and proliferation are not increased in Casp6 KO B cells. Rather than proliferating, activated Casp6 KO B cells preferentially differentiate into syndecan-1+ plasma cells and produce Abs. In Casp6 KO mice compared with WT mice, serum levels of IgG1, IgG2a, and IgG2b are increased and Ag-specific Ab responses are also enhanced along with increased percentages of syndecan-1+ plasma cells. Casp6 may regulate both B cell activation and differentiation by modifying requirements for G0 B cells to enter G1.
Experimental Antibody Therapy of Liver Metastases Reveals Functional Redundancy between FcγRI and FcγRIV
Authors: Otten Marielle A. , van der Bij Gerben J. , Verbeek Sjef J. , Nimmerjahn Falk , Ravetch Jeffrey V. , Beelen Robert H. J. , van de Winkel Jan G. J. , van Egmond Marjolein
Published: April 2014

Many patients with colorectal cancer will develop liver metastases, even after successful surgical removal of the primary tumor at a time at which no visible metastases are present. We previously demonstrated that surgery—although mandatory—paradoxically enhances the risk of developing liver metastases. Because Ab therapy has been acknowledged as a successful strategy to treat malignancies, we studied the potential of postoperative adjuvant Ab therapy to prevent outgrowth of liver metastases. Treatment with murine anti-gp75 (TA99) mAb completely prevented outgrowth of B16F10 liver metastases in over 90% of mice. Therapeutic efficacy was maintained in either C1q- or complement receptor 3-deficient mice but was completely abrogated in FcR γ-chain knockout mice. This indicates that the classical complement pathway was not essential, but interaction with activatory FcγR was necessary for successful therapy. TA99-treatment was still effective in FcγRI−/−, FcγRIII−/−, FcγRI/III−/−, and FcγRI/II/III−/− mice, suggesting an important role for FcγRIV. However, wild-type mice that were treated with TA99 Abs and an FcγRIV blocking Ab (mAb 9E9) were protected against development of liver metastases as well. Only when both FcγRI and FcγRIV functions were simultaneously inhibited, TA99-mediated curative Ab treatment was abrogated, indicating functional redundancy between both IgG receptors in the liver. Furthermore, depletion of liver macrophages (Kupffer cells) reduced the efficacy of Ab therapy, supporting that Kupffer cells are involved as effector cells. Importantly, since Ab treatment almost completely prevented development of liver metastases, postoperative adjuvant Ab therapy may help to improve patient prognosis.
IL-21 Stimulates Human Myeloma Cell Growth through an Autocrine IGF-1 Loop
Authors: Ménoret Emmanuelle , Maïga Sophie , Descamps Géraldine , Pellat-Deceunynck Catherine , Fraslon Caroline , Cappellano Melania , Moreau Philippe , Bataille Régis , Amiot Martine
Published: April 2014

IL-21 is a member of the type I cytokine family related most closely to IL-2 and IL-15. IL-21 is a pleiotropic cytokine, produced by T, NKT, and dendritic cells, which modulates lymphoid and myeloid cell functions. Besides its activities on normal lymphoid cells, it has been shown that IL-21 is a growth factor for myeloma cells. In the present study, we demonstrate that IL-21 generated myeloma colonies from 9 of 24 human myeloma cell lines (HMCL) in a collagen-based assay. Of major interest, the capacity of IL-21 to stimulate clonogenicity was restricted to CD45− HMCL. We found that IL-21 induced tyrosine phosphorylation of STAT-3, STAT-1, and Erk1/2. Interestingly, an Akt activation was observed lately after 30 min to 1 h of IL-21 stimulation, indicating that this Akt phosphorylation could be due to an IGF-1 autocrine loop. This hypothesis was sustained both by the fact that IL-21 treatment induced an IGF-1 mRNA synthesis and that an antagonistic anti-IGF-1 receptor mAb (AVE1642) strongly inhibits the IL-21-induced clonogenicity. Thus, we demonstrated by quantitative PCR that IL-21 induced clonogenicity through an autocrine IGF-1 secretion in HMCL and primary myeloma cells. Because we have previously demonstrated that CD45 phosphatase inhibits the IGF-1 signaling, this inhibitory effect of CD45 explains why the IL-21-induced clonogenicity was restricted to CD45− HMCL. These results support that therapy against IGF-1R, which are presently under investigation in multiple myeloma, could be beneficial, not only to suppress IGF-1-mediated myeloma cell growth, but also IL-21-mediated myeloma cell growth.
Neuropeptide Y Is Expressed by Rat Mononuclear Blood Leukocytes and Strongly Down-Regulated during Inflammation
Authors: Holler Julia , Zakrzewicz Anna , Kaufmann Andreas , Wilhelm Jochen , Fuchs-Moll Gabriele , Dietrich Hartmut , Padberg Winfried , Kuncová Jitka , Kummer Wolfgang , Grau Veronika
Published: April 2014

Neuropeptide Y (NPY), a classical sympathetic comediator, regulates immunological functions including T cell activation and migration of blood leukocytes. A NPY-mediated neuroimmune cross-talk is well conceivable in sympathetically innervated tissues. In denervated, e.g., transplanted organs, however, leukocyte function is not fundamentally disturbed. Thus, we hypothesized that NPY is expressed by blood leukocytes themselves and regulated during inflammation. NPY mRNA and peptide expression were analyzed in mononuclear leukocytes isolated from the blood vessels of healthy rat kidneys, as well as from the blood vessels of isogeneic and allogeneic renal grafts transplanted in the Dark Agouti to Lewis or in the Fischer 344 to Lewis rat strain combination. Depending on the donor strain, acute allograft rejection is either fatal or reversible but both experimental models are characterized by massive accumulation of intravascular leukocytes. Leukocytes, predominantly monocytes, isolated from the blood vessels of untreated kidneys and isografts expressed high amounts of NPY mRNA and peptide, similar to expression levels in sympathetic ganglia. During acute allograft rejection, leukocytic NPY expression drastically dropped to ∼1% of control levels in both rat strain combinations. In conclusion, NPY is an abundantly produced and tightly regulated cytokine of mononuclear blood leukocytes.
IFN-γ-Dependent Regulatory Circuits in Immune Inflammation Highlighted in Diabetes
Authors: Calderon Boris , Suri Anish , Pan Xiaoou O. , Mills Jason C. , Unanue Emil R.
Published: April 2014

We demonstrate diverse roles of IFN-γ in the induction and regulation of immune-mediated inflammation using a transfer model of autoimmune diabetes. The diabetogenic CD4+BDC2.5 (BDC) T cell clone upon transfer into NOD.scid mice induced destruction of islets of Langerhans leading to diabetes. Administration of a neutralizing Ab to IFN-γ (H22) resulted in long-term protection (LTP) from diabetes, with inflammation but persistence of a significant, albeit decreased, number of β cells. BDC T cells were a mixture of cells expressing high, intermediate, and low levels of the TCR. Clonotypelow BDC T cells were required for LTP. Furthermore, islet-infiltrating leukocytes in the LTP mice contained Foxp3+CD4 T cells. Islet inflammation in both diabetic and LTP mice was characterized by heavy infiltration of macrophages. Gene expression profiles indicated that macrophages in diabetic mice were M1 type, while LTP mice contained M2 differentiated. The LTP was abolished if mice were treated with either Ab-depleting CD4 T cells or a neutralizing Ab to CTLA-4, in this case, only at a late stage. Neutralization of IL-10, TGF-β, glucocorticoid-induced TNF receptor (GITR), or CD25 had no effect. Transfer of only clonotypehigh- expressing BDC T cells induced diabetes; in contrast, H22 Abs did not inhibit diabetes. While clonotypehigh T cells induced diabetes even when IFN-γ was neutralized, paradoxically there was reduced inflammation and no diabetes if host myeloid cells lacked IFN-γ receptor. Hence, using monoclonal CD4 T cells, IFN-γ can have a wide diversity of roles, depending on the setting of the immune process.
Dynamin 2 Regulates Granule Exocytosis during NK Cell-Mediated Cytotoxicity
Authors: Arneson Laura N. , Segovis Colin M. , Gomez Timothy S. , Schoon Renee A. , Dick Christopher J. , Lou Zhenkun , Billadeau Daniel D. , Leibson Paul J.
Published: April 2014

NK cells are innate immune cells that can eliminate their targets through granule release. In this study, we describe a specialized role for the large GTPase Dynamin 2 (Dyn2) in the regulation of these secretory events leading to cell-mediated cytotoxicity. By modulating the expression of Dyn2 using small interfering RNA or by inhibiting its activity using a pharmacological agent, we determined that Dyn2 does not regulate conjugate formation, proximal signaling, or granule polarization. In contrast, during cell-mediated killing, Dyn2 localizes with lytic granules and polarizes to the NK cell–target interface where it regulates the final fusion of lytic granules with the plasma membrane. These findings identify a novel role for Dyn2 in the exocytic events required for effective NK cell-mediated cytotoxicity.
TNF-α Is a Positive Regulatory Factor for Human Vγ2Vδ2 T Cells
Authors: Li Haishan , Luo Kun , Pauza C. David
Published: April 2014

Vγ2Vδ2 T cells in human peripheral blood recognize phosphoantigen and play important roles in host defense and immunoregulation. The TCR is required for Vγ2Vδ2 T cell responses to phosphoantigen, but less is known about soluble or cell-associated costimulatory molecules. In this study, we show that human Vγ2Vδ2 T cell responses to phosphoantigen, including activation, proliferation, cytokine production, and tumor cell cytotoxicity, require TNF-α binding to its receptor, with a preference for TNFR2. Because stimulated Vγ2Vδ2 cells also produce TNF-α, this may be a positive control mechanism to sustain the response. Impaired proliferation in the presence of TNF-α or TNFR blocking agents was partially rescued by a TLR2 agonist, Pam3Cys. Our studies demonstrate that TNF-α plays a critical role in regulating human Vγ2Vδ2 T cell immune responses.
Dendritic Cells Genetically Engineered to Express IL-10 Induce Long-Lasting Antigen-Specific Tolerance in Experimental Asthma
Authors: Henry Emmanuelle , Desmet Christophe J. , Garzé Virginie , Fiévez Laurence , Bedoret Denis , Heirman Carlo , Faisca Pedro , Jaspar Fabrice J. , Gosset Philippe , Jacquet Alain P. A. , Desmecht Daniel , Thielemans Kris , Lekeux Pierre , Moser Muriel , Bureau Fabrice
Published: April 2014

Dendritic cells (DCs) are professional APCs that have a unique capacity to initiate primary immune responses, including tolerogenic responses. We have genetically engineered bone marrow-derived DCs to express the immunosuppressive cytokine IL-10 and tested the ability of these cells to control experimental asthma. A single intratracheal injection of OVA-pulsed IL-10-transduced DCs (OVA-IL-10-DCs) to naive mice before OVA sensitization and challenge prevented all of the cardinal features of airway allergy, namely, eosinophilic airway inflammation, airway hyperreactivity, and production of mucus, Ag-specific Igs, and IL-4. OVA-IL-10-DCs also reversed established experimental asthma and had long-lasting and Ag-specific effects. We furthermore showed, by using IL-10-deficient mice, that host IL-10 is required for mediating the immunomodulatory effects of OVA-IL-10-DCs and demonstrated a significant increase in the percentage of OVA-specific CD4+CD25+Foxp3+IL-10+ regulatory T cells in the mediastinal lymph nodes of OVA-IL-10-DC-injected mice. Finally, adoptive transfer of CD4+ mediastinal lymph node T cells from mice injected with OVA-IL-10-DCs protected OVA-sensitized recipients from airway eosinophilia upon OVA provocation. Our study describes a promising strategy to induce long-lasting Ag-specific tolerance in airway allergy.
Mechanisms of Oncostatin M-Induced Pulmonary Inflammation and Fibrosis
Authors: Mozaffarian Afsaneh , Brewer Avery W. , Trueblood Esther S. , Luzina Irina G. , Todd Nevins W. , Atamas Sergei P. , Arnett Heather A.
Published: April 2014

Oncostatin M (OSM), an IL-6 family cytokine, has been implicated in a number of biological processes including the induction of inflammation and the modulation of extracellular matrix. In this study, we demonstrate that OSM is up-regulated in the bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis and scleroderma, and investigate the pathological consequences of excess OSM in the lungs. Delivery of OSM to the lungs of mice results in a significant recruitment of inflammatory cells, as well as a dose-dependent increase in collagen deposition in the lungs, with pathological correlates to characteristic human interstitial lung disease. To better understand the relationship between OSM-induced inflammation and OSM-induced fibrosis, we used genetically modified mice and show that the fibrotic response is largely independent of B and T lymphocytes, eosinophils, and mast cells. We further explored the mechanisms of OSM-induced inflammation and fibrosis using both protein and genomic array approaches, generating a “fibrotic footprint” for OSM that shows modulation of various matrix metalloproteinases, extracellular matrix components, and cytokines previously implicated in fibrosis. In particular, although the IL-4/IL-13 and TGF-β pathways have been shown to be important and intertwined of fibrosis, we show that OSM is capable of inducing lung fibrosis independently of these pathways. The demonstration that OSM is a potent mediator of lung inflammation and extracellular matrix accumulation, combined with the up-regulation observed in patients with pulmonary fibrosis, may provide a rationale for therapeutically targeting OSM in human disease.
Fibrillar Amyloid-β Peptides Activate Microglia via TLR2: Implications for Alzheimer’s Disease
Authors: Jana Malabendu , Palencia Carlos A. , Pahan Kalipada
Published: April 2014

Microglial activation is an important pathological component in brains of patients with Alzheimer’s disease (AD), and fibrillar amyloid-β (Aβ) peptides play an important role in microglial activation in AD. However, mechanisms by which Aβ peptides induce the activation of microglia are poorly understood. The present study underlines the importance of TLR2 in mediating Aβ peptide-induced activation of microglia. Fibrillar Aβ1–42 peptides induced the expression of inducible NO synthase, proinflammatory cytokines (TNF-α, IL-1β, and IL-6), and integrin markers (CD11b, CD11c, and CD68) in mouse primary microglia and BV-2 microglial cells. However, either antisense knockdown of TLR2 or functional blocking Abs against TLR2 suppressed Aβ1–42-induced expression of proinflammatory molecules and integrin markers in microglia. Aβ1–42 peptides were also unable to induce the expression of proinflammatory molecules and increase the expression of CD11b in microglia isolated from TLR2−/− mice. Finally, the inability of Aβ1–42 peptides to induce the expression of inducible NO synthase and to stimulate the expression of CD11b in vivo in the cortex of TLR2−/− mice highlights the importance of TLR2 in Aβ-induced microglial activation. In addition, ligation of TLR2 alone was also sufficient to induce microglial activation. Consistent to the importance of MyD88 in mediating the function of various TLRs, antisense knockdown of MyD88 also inhibited Aβ1–42 peptide-induced expression of proinflammatory molecules. Taken together, these studies delineate a novel role of TLR2 signaling pathway in mediating fibrillar Aβ peptide-induced activation of microglia.
TGF-β1 Attenuates Mediator Release and De Novo Kit Expression by Human Skin Mast Cells through a Smad-Dependent Pathway
Authors: Zhao Wei , Gomez Gregorio , Yu Shao-Hua , Ryan John J. , Schwartz Lawrence B.
Published: April 2014

TGF-β has pleiotropic effects on many cell types at different stages of their development, including mast cells. The present study examines the effects of TGF-β on human skin mast cells of the MCTC type. The expression of TGF-β receptors (TGF-R) was verified at the mRNA and protein levels for TGF-RI and TGF-RII, and at the mRNA level for accessory molecules β-glycan and endoglin. TGF-β did not affect mast cell viability after 1 wk at concentrations ≤10 ng/ml, but at 50 ng/ml caused significant cell death. TGF-β inhibited surface and total expression of Kit in a dose-dependent manner, whereas the surface expression of FcεRI, FcγRI, and FcγRII was not affected. TGF-β inhibited degranulation and cytokine production, but not PGD2 production. TGF-β diminished surface Kit expression through a TGF-RI kinase/Smad-dependent pathway by inhibiting new synthesis of Kit protein, which became evident following internalization and degradation of Kit after mast cells were exposed to the Kit ligand, stem cell factor. In contrast, addition of TGF-β had no discernible effect on surface Kit expression when administered 3 days after stem cell factor, by which time surface Kit levels had returned to baseline. Although both transcription and translation are important for de novo expression of Kit, Kit mRNA levels were not affected by TGF-β. Therefore, transcription of a gene other than Kit might be involved in Kit expression. Finally, activation of mast cells increased their susceptibility to TGF-β-mediated apoptosis, a process that might regulate the survival of activated mast cells in vivo.
NF-κB-Driven STAT2 and CCL2 Expression in Astrocytes in Response to Brain Injury
Authors: Khorooshi Reza , Babcock Alicia A. , Owens Trevor
Published: April 2014

Tissue response to injury includes expression of genes encoding cytokines and chemokines. These regulate entry of immune cells to the injured tissue. The synthesis of many cytokines and chemokines involves NF-κB and signal transducers and activators of transcription (STAT). Injury to the CNS induces glial response. Astrocytes are the major glial population in the CNS. We examined expression of STATs and the chemokine CCL2 and their relationship to astroglial NF-κB signaling in the CNS following axonal transection. Double labeling with Mac-1/CD11b and glial fibrillary acidic protein revealed that STAT2 up-regulation and phosphorylation colocalized exclusively to astrocytes, suggesting the involvement of STAT2 activating signals selectively in astroglial response to injury. STAT1 was also up-regulated and phosphorylated but not exclusively in astrocytes. Both STAT2 up-regulation and phosphorylation were NF-κB -dependent since they did not occur in the lesion-reactive hippocampus of transgenic mice with specific inhibition of NF-κB activation in astrocytes. We further showed that lack of NF-κB signaling significantly reduced injury-induced CCL2 expression as well as leukocyte infiltration. Our results suggest that NF-κB signaling in astrocytes controls expression of both STAT2 and CCL2, and thus regulates infiltration of leukocytes into lesion-reactive hippocampus after axonal injury. Taken together, these findings indicate a central role for astrocytes in directing immune-glial interaction in the CNS injury response.
The Effect of the JNK Inhibitor, JIP Peptide, on Human T Lymphocyte Proliferation and Cytokine Production
Authors: Melino Michelle , Hii Charles S. , McColl Shaun R. , Ferrante Antonio
Published: April 2014

Although JNK is a potential target for treating chronic inflammatory diseases, its role in T lymphocyte function remains controversial. To overcome some of the previous limitations in addressing this issue we have used the recently described transactivator of transcription-JNK-interacting protein (TAT-JIP) peptide, a specific inhibitor that was derived from the minimal JNK-binding region of the scaffold protein, JNK-interacting protein 1 (JIP-1), coupled to the short cell-permeable HIV TAT sequence. Pretreatment of purified human T lymphocytes with the TAT-JIP peptide inhibited the phosphorylation of endogenous jun activated by PHA-PMA. This was associated with a corresponding inhibition of lymphoproliferation, and of IL-2, IFN-γ, lymphotoxin, and IL-10 cytokine production. Similar results were also found using mouse splenic T cells. Examination of the specificity of TAT-JIP revealed that although the peptide was more selective than the pharmacological inhibitor, SP600125, it also inhibited cyclin-dependent kinase 2, p70 ribosomal protein S6 kinase, and serum and glucocorticoid-regulated kinase activity. Nevertheless, these data demonstrate for the first time the ability of the TAT-JIP peptide to inhibit the JNK pathway and the phosphorylation of jun in intact cells, thereby preventing the activation of the transcription factor, AP-1, and the production of Th1 and Th2 cytokines. Thus JNK could potentially be a target for the development of drugs for the treatment of autoimmune inflammatory diseases.
Active Caspase-1-Mediated Secretion of Retinoic Acid Inducible Gene-I
Authors: Kim Min-Jung , Yoo Joo-Yeon
Published: April 2014

Caspase-1 is an inflammatory caspase that controls the activation and secretion of the inflammatory cytokines, IL-1β and IL-18. We observed that cellular levels of retinoic acid-inducible gene-I (RIG-I) were enhanced when the pan-caspase inhibitor Z-VAD-fmk or caspase-1-specific inhibitor Z-WEHD-fmk blocked caspase activity. Overexpression of caspase-1 reduced cellular levels of RIG-I and inhibited RIG-I-mediated signaling activity. Enzymatic activity of caspase-1 was necessary to control RIG-I, although it was not a substrate of proteolytic cleavage by caspase-1. Caspase-1 physically interacted with full length RIG-I, but not with mutant forms lacking either the amino- or carboxyl-terminal domains. RIG-I was present in the supernatant of cells transfected with active caspase-1 but not with caspase-4. Stimulating cells with LPS and ATP also induced secretion of endogenous RIG-I in macrophages. Our data suggest a novel mechanism that negatively regulates RIG-I-mediated signaling activity via caspase-1-dependent secretion of RIG-I protein.
Oncostatin M-Induced and Constitutive Activation of the JAK2/STAT5/CIS Pathway Suppresses CCL1, but Not CCL7 and CCL8, Chemokine Expression
Authors: Hintzen Christoph , Haan Claude , Tuckermann Jan P. , Heinrich Peter C. , Hermanns Heike M.
Published: April 2014

The recruitment of leukocytes to injured tissue is crucial for the initiation of inflammatory responses as well as for immune surveillance to fight tumor progression. In this study, we show that oncostatin M, a member of the IL-6-type cytokine family and potent proinflammatory cytokine stimulates the expression of the chemokines CCL1, CCL7, and CCL8 in primary human dermal fibroblasts at a faster kinetic than IL-1β or TNF-α. The production of CCL1 and CCL8 is important for migration of monocytes, while specific Abs against CCL1 additionally inhibit the migration of T lymphocytes. We identify the mitogen-activated protein kinases ERK1/2 and p38 as crucial factors for the enhanced expression of CCL1 and CCL8. Depletion of the ERK1/2 target genes c-Jun or c-Fos strongly decrease CCL1 and CCL8 expression, while p38 MAPK prolongs the half-life of CCL1, CCL7, and CCL8 mRNA through inhibition of tristetraprolin. None of the STAT transcription factors STAT1, STAT3, or STAT5 stimulate transcription of CCL1 or CCL8. However, we identify a negative regulatory function of activated STAT5 for the gene expression of CCL1. Importantly, not STAT5 itself, but its target gene cytokine inducible SH2-domain containing protein is required for the STAT5 inhibitory effect on CCL1 expression. Finally, we show that constitutive activation of STAT5 through a mutated form of JAK2 (JAK2 V617F) occurring in patients with myeloproliferative disorders similarly suppresses CCL1 expression. Taken together, we identify novel important inflammatory target genes of OSM which are independent of STAT signaling per se, but depend on MAPK activation and are partly repressed through STAT5-dependent expression of cytokine inducible SH2-domain containing protein.
Measles Virus Infection in Adults Induces Production of IL-10 and Is Associated with Increased CD4+CD25+ Regulatory T Cells
Authors: Yu Xue-lian , Cheng Yu-ming , Shi Bi-sheng , Qian Fang-xing , Wang Feng-bin , Liu Xi-nian , Yang Hai-ying , Xu Qing-nian , Qi Tang-kai , Zha Li-jun , Yuan Zheng-hong , Ghildyal Reena
Published: April 2014

Despite steady progress in elimination of measles virus globally, measles infection still causes 500,000 annual deaths, mostly in developing countries where endemic measles strains still circulate. Many adults are infected every year in China, with symptoms more severe than those observed in children. In this study, we have used blood samples from adult measles patients in Shanghai and age-matched healthy controls to gain an understanding of the immune status of adult measles patients. IFN-α mRNA was reduced in patient PBMC compared with healthy controls. In contrast, gene expression and plasma production of IL-2, IL-10, and IFN-γ were elevated in patient blood. A similar cytokine profile was observed at early times when cultured PBMC were infected with a clinical isolate of measles virus. In contrast to previous studies in pediatric patients, we did not find a reduction in total CD4+ and CD8+ T cells in patient PBMC. Interestingly, we found that CD4+CD25+CD127low regulatory T cells were significantly increased in patient PBMC compared with controls. Using intracellular cytokine staining we also show that the measles virus induces IL-10-producing CD14+ and CD4+CD25+ cells in PBMC. Our results show that adult measles patients in the acute phase of the disease have a mixed Th1/Th2 type response, accompanied with severe immunosuppression of both innate and adaptive responses including suppression of type I IFN. Both regulatory T cells and plasma IL-10 may contribute to the immunosuppression.
Sunlight Triggers Cutaneous Lupus through a CSF-1-Dependent Mechanism in MRL-Fas
lpr Mice
Authors: Menke Julia , Hsu Mei-Yu , Byrne Katelyn T. , Lucas Julie A. , Rabacal Whitney A. , Croker Byron P. , Zong Xiao-Hua , Stanley E. Richard , Kelley Vicki R.
Published: April 2014

Sunlight (UVB) triggers cutaneous lupus erythematosus (CLE) and systemic lupus through an unknown mechanism. We tested the hypothesis that UVB triggers CLE through a CSF-1-dependent, macrophage (Mø)-mediated mechanism in MRL-Faslpr mice. By constructing mutant MRL-Faslpr strains expressing varying levels of CSF-1 (high, intermediate, none), and use of an ex vivo gene transfer to deliver CSF-1 intradermally, we determined that CSF-1 induces CLE in lupus-susceptible MRL-Faslpr mice, but not in lupus-resistant BALB/c mice. UVB incites an increase in Møs, apoptosis in the skin, and CLE in MRL-Faslpr, but not in CSF-1-deficient MRL-Faslpr mice. Furthermore, UVB did not induce CLE in BALB/c mice. Probing further, UVB stimulates CSF-1 expression by keratinocytes leading to recruitment and activation of Møs that, in turn, release mediators, which induce apoptosis in keratinocytes. Thus, sunlight triggers a CSF-1-dependent, Mø-mediated destructive inflammation in the skin leading to CLE in lupus-susceptible MRL-Faslpr but not lupus-resistant BALB/c mice. Taken together, CSF-1 is envisioned as the match and lupus susceptibility as the tinder leading to CLE.
Cutting Edge: CD4+ T Cell-Derived IL-2 Is Essential for Help-Dependent Primary CD8+ T Cell Responses
Authors: Wilson Elizabeth B. , Livingstone Alexandra M.
Published: April 2014

CD4+ T cell help is essential for primary CD8+ T cell responses to noninflammatory Ags. IL-2 is one of the principal cytokines made by naive CD4+ T cells, and we show in this study that it is an essential component of help. Adoptively transferred naive CD4+ TCR-transgenic OT-II cells supported endogenous primary CD8+ T cell responses, but IL-2-deficient OT-II cells were unable to provide help, although they responded to Ag in vivo and up-regulated CD40 ligand in vitro. Wild -type OT-II cells helped endogenous CD8+ T cell responses in IL-2-deficient mice, but not in IL-2Rα-deficient mice. Thus, CD4+ T cell-derived IL-2 is essential for CD8+ T cell responses to noninflammatory, cell-associated Ags. We suggest that it is also a critical component of help for CD8+ T cell responses to pathogens, because protective memory also requires CD8+ T cell stimulation by IL-2 during priming.
Requirement of IL-17RA in Con A Induced Hepatitis and Negative Regulation of IL-17 Production in Mouse T Cells
Authors: Nagata Takako , Mckinley Laura , Peschon Jacques J. , Alcorn John F. , Aujla Shean J. , Kolls Jay K.
Published: April 2014

Th17 cells, a subset of T cells involved in autoimmunity and host defense against extracellular Gram-negative infection, express both IL-17A and IL-17F. Both IL-17A and IL-17F can signal via the IL-17RA; however, IL-17F does so at a 1- to 2-log higher concentration than IL-17A. In this study, we show that the IL-17F homodimer via IL-17RA is a negative regulator of IL-17 production in T cells and suggest a mechanism whereby IL-17RA on T cells serves as an autocrine/paracrine regulator of IL-17 synthesis in T cells.
Lin−Sca1+Kit− Bone Marrow Cells Contain Early Lymphoid-Committed Precursors That Are Distinct from Common Lymphoid Progenitors
Authors: Kumar Ritu , Fossati Valentina , Israel Mason , Snoeck Hans-Willem
Published: April 2014

The significance of a population in mouse bone marrow of lineage-negative (Lin−), Sca1-positive, c-kit-negative (LSK−) cells, which is reported to be devoid of long-term repopulation capacity or myeloid potential, is unknown. In this study, we show that the LSK− population is composed of several subsets defined by the expression of flt3, CD25, and IL-7Rα. The first subset was CD25− and more than 90% expressed either flt3, IL-7Rα, or both. The CD25−LSK− population had T cell, B cell, and NK cell potential in vivo, and most of this activity was localized in the flt3+ subset, irrespective of the expression of IL-7Rα. Although lymphoid potential of flt3+LSK− cells in vivo was 3-fold lower than that of lin−Sca1lowkitlowIL7Rα+ common lymphoid progenitors (CLPs), their cloning efficiency in vitro was 10-fold lower than that of CLPs. Furthermore, although the myeloid potential of flt3+LSK− cells was 10-fold lower than that of CLPs in the absence of M-CSF, the relative myeloid potential of both populations was similar in its presence. These observations suggest differential growth factor requirements of both populations. The second subset of LSK− cells was homogeneously CD25+flt3−IL7Rα+ and could be generated from both CD25−LSK− cells and from CLPs, but did not engraft in immunodeficient Rag1−/− or Rag1−/−γc−/− hosts. This population, of which the significance is unclear, was increased in Rag1−/− mice and in old mice. Thus, the LSK− population is phenotypically and functionally heterogeneous and contains early lymphoid-committed precursors. Our findings imply that the early stages of lymphoid commitment are more complex than was thus far assumed.
Deregulation of c-Myc Confers Distinct Survival Requirements for Memory B Cells, Plasma Cells, and Their Progenitors
Authors: Khuda Sefat E. , Loo William M. , Janz Siegfried , Van Ness Brian , Erickson Loren D.
Published: April 2014

Deregulation of the c-Myc oncogene is tightly associated with human and murine plasma cell (PC) neoplasms. Through the analysis of Ag-specific B cell responses in mice where Myc is targeted to the Igh Cα locus, we show here that c-Myc dramatically impairs the primary and secondary Ab response. This impairment is differentiation stage specific, since germinal center B cell formation, affinity maturation, and class switch recombination were intact. Examination of PC viability revealed that c-Myc triggered apoptosis only upon final maturation when Ab is secreted and is resistant to the survival factor BAFF (B cell-activating factor belonging to the TNF family). In contrast, PC precursors (PCpre) that ultimately give rise to mature PCs survived normally and vigorously expanded with BAFF signaling. We further show that c-Myc also facilitates the apoptosis of memory B cells. Thus, Cα-Myc controls both cellular arms of long-lived B cell immunity than previously anticipated. Only when deregulation of c-Myc was combined with enforced Bcl-xL expression were mature PCs able to survive in response to BAFF. These data indicate that the survival requirements for tumor-susceptible PCpre and PCs are distinct and that tumor progression likely develops as PCpre transition to functional PCs when apoptotic pathways such as members of the Bcl-2 family are disabled.
A New Approach to the Blocking of Alloreactive T Cell-Mediated Graft-versus-Host Disease by In Vivo Administration of Anti-CXCR3 Neutralizing Antibody
Authors: He Shan , Cao Qi , Qiu Yuhua , Mi Jianqing , Zhang Jingwu Z. , Jin Min , Ge Hailiang , Emerson Stephen G. , Zhang Yi , Zhang Yanyun
Published: April 2014

Chemokines and chemokine receptors play critical roles in directing the migration of alloreactive donor T cells into graft-vs-host disease (GVHD) target organs. However, blockade of GVHD by antagonist Ab against chemokine receptors remains an elusive goal. Using a mouse model of human GVHD, we demonstrate that in vivo administration of anti-CXCR3 Ab for 21 days (long-term), but not for 7 days (short-term), inhibits alloreactive CD8+ T cell-mediated GVHD. During a graft-vs-host reaction, infused donor CD8+ T cells generate two subsets of potent inducers of GVHD: CXCR3+CD8+ and CXCR3−CD8+ T cells. Compared with CXCR3+CD8+ T cells, CXCR3−CD8+ T cells produce less granzyme B, Fas ligand, IFN-γ, and TNF-α. Interestingly, stimulation with either dendritic cells or IL-2 induces a dynamic conversion between CXCR3+CD8+ and CXCR3−CD8+ T cells. Short-term anti-CXCR3 Ab treatment inhibits only CXCR3+CD8+ T cell-mediated GVHD, but not the disease induced by CXCR3−CD8+ T cells. Prolonged in vivo administration of anti-CXCR3 Ab significantly reduces the infiltration of alloreactive CD8+ T cells into GVHD target organs and inhibits GVHD mediated by either CXCR3+CD8+ or CXCR3−CD8+ T cells. Thus, we have established a novel and effective approach with the potential to give rise to new clinical methods for preventing and treating GVHD after allogeneic hematopoietic stem cell transplantation.
The Immunosuppressor Mycophenolic Acid Kills Activated Lymphocytes by Inducing a Nonclassical Actin-Dependent Necrotic Signal
Authors: Chaigne-Delalande Benjamin , Guidicelli Gwendaline , Couzi Lionel , Merville Pierre , Mahfouf Walid , Bouchet Stéphane , Molimard Mathieu , Pinson Benoit , Moreau Jean-François , Legembre Patrick
Published: April 2014

Mycophenolate mofetil (MMF) is an immunosuppressive agent used in transplantation. Over the last decade, MMF has also emerged as an alternative therapeutic regimen for autoimmune diseases, mainly for patients refractory to other therapies. The active compound of MMF, mycophenolic acid (MPA), depletes the intracellular pool of guanosine tri-phosphate through inosine monophosphate dehydrogenase blockade. The molecular mechanism involved in the elimination of T and B lymphocytes upon inhibition of inosine monophosphate dehydrogenase remains elusive. In this study, we showed that in contrast to the immunosuppressors azathioprine, cyclosporin A, and tacrolimus, MPA killed lymphocytes through the activation of a caspase-independent necrotic signal. Furthermore, the MPA-mediated necrotic signal relied on the transmission of a novel intracellular signal involving Rho-GTPase Cdc42 activity and actin polymerization. In addition to its medical interest, this study sheds light on a novel and atypical molecular mechanism leading to necrotic cell death.
Signals and Sequences That Control CD28 Localization to the Central Region of the Immunological Synapse
Authors: Sanchez-Lockhart Mariano , Graf Beth , Miller Jim
Published: April 2014

During T cell interaction with APC, CD28 is recruited to the central region (cSMAC) of the immunological synapse. CD28-mediated signaling through PI3K results in the recruitment of protein kinase C-θ (PKCθ) to the cSMAC, activation of NF-κB, and up-regulation of IL-2 transcription. However, the mechanism that mediates CD28 localization to the cSMAC and the functional consequences of CD28 localization to the cSMAC are not understood. In this report, we show that CD28 recruitment and persistence at the immunological synapse requires TCR signals and CD80 engagement. Addition of mAb to either MHC class II or CD80 results in the rapid displacement of CD28 from the immunological synapse. Ligand binding is not sufficient for CD28 localization to the immunological synapse, as truncation of the cytosolic tail of CD28 disrupts synapse localization without effecting the ability of CD28 to bind CD80. Furthermore, a single point mutation in the CD28 cytosolic tail (tyrosine 188) interferes with the ability of CD28 to preferentially accumulate at the cSMAC. PKCθ distribution at the immunological synapse mirrors the distribution of tyrosine 188-mutated CD28, indicating that CD28 drives the localization of PKCθ even when CD28 is not localized to the cSMAC. Mutation of tyrosine 188 also results in diminished activation of NF-κB, suggesting that CD28-mediated localization of PKCθ to the cSMAC is important for efficient signal transduction. These data reinforce the importance of the interplay of signals between TCR and CD28 and suggest that CD28 signaling through PCKθ may be mediated through localization to the cSMAC region of the immunological synapse.
Abnormal Regulatory and Effector T Cell Function Predispose to Autoimmunity following Xenogeneic Thymic Transplantation
Authors: Fudaba Yasuhiro , Onoe Takashi , Chittenden Meredith , Shimizu Akira , Shaffer Juanita M. , Bronson Roderick , Sykes Megan
Published: April 2014

Porcine thymus grafts support robust murine and human thymopoiesis, generating a diverse T cell repertoire that is deleted of donor and host-reactive cells, achieving specific xenograft tolerance. Positive selection is mediated exclusively by the xenogeneic thymic MHC. Although thymectomized, T cell-depleted normal mice usually remain healthy following xenogeneic thymic transplantation, thymus-grafted congenitally athymic mice frequently develop multiorgan autoimmunity. We investigated the etiology of this syndrome by adoptively transferring lymphocyte populations from fetal pig thymus-grafted BALB/c nude mice to secondary BALB/c nude recipients. Fetal pig thymus-grafted nude mice generated normal numbers of CD25+Foxp3+CD4 T cells, but these cells lacked the capacity to block autoimmunity. Moreover, thymocytes and peripheral CD4+CD25− cells from fetal pig thymus-grafted nude mice, but not those from normal mice, induced autoimmunity in nude recipients. Injection of thymic epithelial cells from normal BALB/c mice into fetal pig thymus grafts reduced autoimmunity and enhanced regulatory function of splenocytes. Our data implicate abnormalities in postthymic maturation, expansion, and/or survival of T cells positively selected by a xenogeneic MHC, as well as incomplete intrathymic deletion of thymocytes recognizing host tissue-specific Ags, in autoimmune pathogenesis. Regulatory cell function is enhanced and negative selection of host-specific thymocytes may potentially also be improved by coimplantation of recipient thymic epithelial cells in the thymus xenograft.
Galectin-9 Increases Tim-3+ Dendritic Cells and CD8+ T Cells and Enhances Antitumor Immunity via Galectin-9-Tim-3 Interactions
Authors: Nagahara Keiko , Arikawa Tomohiro , Oomizu Souichi , Kontani Keiichi , Nobumoto Atsuya , Tateno Hiroaki , Watanabe Kota , Niki Toshiro , Katoh Shigeki , Miyake Minoru , Nagahata Syun-Ichiro , Hirabayashi Jun , Kuchroo Vijay K. , Yamauchi Akira , Hirashima Mitsuomi
Published: April 2014

A Tim-3 ligand, galectin-9 (Gal-9), modulates various functions of innate and adaptive immune responses. In this study, we demonstrate that Gal-9 prolongs the survival of Meth-A tumor-bearing mice in a dose- and time-dependent manner. Although Gal-9 did not prolong the survival of tumor-bearing nude mice, transfer of naive spleen cells restored a prolonged Gal-9-induced survival in nude mice, indicating possible involvement of T cell-mediated immune responses in Gal-9-mediated antitumor activity. Gal-9 administration increased the number of IFN-γ-producing Tim-3+ CD8+ T cells with enhanced granzyme B and perforin expression, although it induced CD4+ T cell apoptosis. It simultaneously increased the number of Tim-3+CD86+ mature dendritic cells (DCs) in vivo and in vitro. Coculture of CD8+ T cells with DCs from Gal-9-treated mice increased the number of IFN-γ producing cells and IFN-γ production. Depletion of Tim-3+ DCs from DCs of Gal-9-treated tumor-bearing mice decreased the number of IFN-γ-producing CD8+ T cells. Such DC activity was significantly abrogated by Tim-3-Ig, suggesting that Gal-9 potentiates CD8+ T cell-mediated antitumor immunity via Gal-9-Tim-3 interactions between DCs and CD8+ T cells.
An In Vitro System to Model the Establishment and Reactivation of HIV-1 Latency
Authors: Marini Alessandra , Harper Jill M. , Romerio Fabio
Published: April 2014

HIV-1 establishes latency primarily by infecting activated CD4+ T cells that later return to quiescence as memory cells. Latency allows HIV-1 to evade immune responses and to persist during antiretroviral therapy, which represents an important problem in clinical practice. The lack of a valid cellular model to study HIV-1 latency has hindered advances in the understanding of its biology. In this study, we attempted to model HIV-1 latency using human primary CD4+ T cells infected in vitro with HIV-1 after activation with Ag-loaded dendritic cells and then brought back to quiescence through a resting phase in the presence of IL-7. During the resting phase, expression of cellular activation markers disappeared and cell proliferation and viral replication ceased, but resumed following restimulation of rested cells with Ag or mAbs directed to CD3/CD28. In addition, higher cell death rates were observed in HIV-1-infected than uninfected cultures during secondary but not primary stimulation. Thus, this system may allow us to study the biology of HIV-1 latency, as well as the mechanisms of CD4+ T cell death following HIV-1 reactivation.
The Magnitude of Thymic Output Is Genetically Determined through Controlled Intrathymic Precursor T Cell Proliferation
Authors: Dulude Gaël , Cheynier Remi , Gauchat Dominique , Abdallah Ali , Kettaf Nadia , Sékaly Rafick-Pierre , Gratton Sophie
Published: April 2014

The thymus plays a crucial role in providing the immune system with naive T cells showing a diverse TCR repertoire. Whereas the diversity of thymic production is mainly ensured by TCR rearrangement at both the TRA and TRB loci, the number of cells reaching the double-positive differentiation stage defines the extent of thymic output. A quantitative analysis of TCR excision circles (TREC; signal-joint TRECs and DJβTRECs) produced at different stages of thymopoiesis was performed in nine laboratory mouse strains. The results clearly demonstrate that the magnitude of thymic output is directly proportional to the extent of proliferation in the double-negative 4 thymocyte subset. Strikingly, intrathymic precursor T cell proliferation was found to be strain dependent, thus suggesting a genetic regulation of thymic output. The inherited character of thymic output was further confirmed by the transmission of the phenotype in a recessive fashion in F1 progeny of the different parental strains. Our results provide the first demonstration of the genetic regulation of thymic output.
TCR β-Chain Sharing in Human CD8+ T Cell Responses to Cytomegalovirus and EBV
Authors: Venturi Vanessa , Chin Hui Yee , Asher Tedi E. , Ladell Kristin , Scheinberg Phillip , Bornstein Ethan , van Bockel David , Kelleher Anthony D. , Douek Daniel C. , Price David A. , Davenport Miles P.
Published: April 2014

The CD8+ TCR repertoires specific for many immunogenic epitopes of CMV and EBV are dominated by a few TCR clonotypes and involve public TCRs that are shared between many MHC-matched individuals. In previous studies, we demonstrated that the observed sharing of epitope-specific TCRβ chains between individuals is strongly associated with TCRβ production frequency, and that a process of convergent recombination facilitates the more efficient production of some TCRβ sequences. In this study, we analyzed a total of 2836 TCRβ sequences from 23 CMV-infected and 10 EBV-infected individuals to investigate the factors that influence the sharing of TCRβ sequences in the CD8+ T cell responses to two immunodominant HLA-A*0201-restricted epitopes from these viruses. The most shared TCRβ amino acid sequences were found to have two features that indicate efficient TCRβ production, as follows: 1) they required fewer nucleotide additions, and 2) they were encoded by a greater variety of nucleotide sequences. We used simulations of random V(D)J recombination to demonstrate that the in silico TCRβ production frequency was predictive of the extent to which both TCRβ nucleotide and amino acid sequences were shared in vivo. These results suggest that TCRβ production frequency plays an important role in the interindividual sharing of TCRβ sequences within CD8+ T cell responses specific for CMV and EBV.