bluuebunny/crossref_metadata_2025 huggingface dataset:
Cutting Edge: Novel Human Dendritic Cell- and Monocyte-Attracting Chemokine-Like Protein Identified by Fold Recognition Methods
Authors: Pisabarro M. Teresa , Leung Beatrice , Kwong Mandy , Corpuz Racquel , Frantz Gretchen D. , Chiang Nancy , Vandlen Richard , Diehl Lauri J. , Skelton Nicholas , Kim Hok Seon , Eaton Dan , Schmidt Kerstin N.
Published: April 2014

Chemokines play an important role in the immune system by regulating cell trafficking in homeostasis and inflammation. In this study, we report the identification and characterization of a novel cytokine-like protein, DMC (dendritic cell and monocyte chemokine-like protein), which attracts dendritic cells and monocytes. The key to the identification of this putative new chemokine was the application of threading techniques to its uncharacterized sequence. Based on our studies, DMC is predicted to have an IL-8-like chemokine fold and to be structurally and functionally related to CXCL8 and CXCL14. Consistent with our predictions, DMC induces migration of monocytes and immature dendritic cells. Expression studies show that DMC is constitutively expressed in lung, suggesting a potential role for DMC in recruiting monocytes and dendritic cells from blood into lung parenchyma.
Cutting Edge: Gut Microenvironment Promotes Differentiation of a Unique Memory CD8 T Cell Population
Authors: Masopust David , Vezys Vaiva , Wherry E. John , Barber Daniel L. , Ahmed Rafi
Published: April 2014

Whether tissue microenvironment influences memory CD8 T cell differentiation is unclear. We demonstrate that virus-specific intraepithelial lymphocytes in gut resemble neither central nor effector memory CD8 T cells isolated from spleen or blood. This unique phenotype arises in situ within the gut, suggesting that anatomic location plays an inductive role in the memory differentiation program. In support of this hypothesis, memory CD8 T cells changed phenotype upon change in location. After transfer and in vivo restimulation, gut or spleen memory cells proliferated, disseminated into spleen and gut, and adopted the memory T cell phenotype characteristic of their new environment. Our data suggests that anatomic location directly impacts the memory T cell differentiation program.
CD11b+/Gr-1+ Myeloid Suppressor Cells Cause T Cell Dysfunction after Traumatic Stress
Authors: Makarenkova Valeriya P. , Bansal Vishal , Matta Benjamin M. , Perez Lori Ann , Ochoa Juan B.
Published: April 2014

T cell dysfunction that occurs after surgery or trauma is associated with a poor clinical outcome. We describe that myeloid suppressor cells expressing CD11b+/Gr-1+ markers invade the spleen after traumatic stress and suppress T cell function through the production of arginase 1. We created a consistent model of traumatic stress in C57BL/6 mice to perform this work. A significant number of CD11b+/Gr-1+ cells expressing arginase 1 accumulated in T cell zones around the germinal centers of the white pulp of the spleen within 6 h of trauma and lasted for at least 72 h. Increased arginase activity and arginase 1 expression, along with increased [3H]arginine uptake, l-arginine depletion, and l-ornithine accumulation in the culture medium, were observed exclusively in CD11b+/Gr-1+ cells after traumatic stress. Flow cytometry revealed CD11b+/Gr-1+ as a heterogeneous myeloid suppressor cell also expressing low levels of MHC class I and II, CD80, CD86, CD31, and others. When compared with controls, trauma-induced CD11b+/Gr-1+ cells significantly inhibited CD3/CD28-mediated T cell proliferation, TCR ζ-chain expression, and IL-2 production. The suppressive effects by trauma CD11b+/Gr-1+ cells were overcome with the arginase antagonist N-hydroxy-nor-l-arginine or extrasupplementation of medium with l-arginine. Poor Ag-presenting capacity of control and trauma-induced CD11b+/Gr-1+ cells was detected in allogeneic murine leukocyte reaction. This study demonstrates that CD11b+/Gr-1+ cells invade the spleen following traumatic stress and cause T cell dysfunction by an arginase-mediated mechanism, probably that of arginine depletion. Understanding the mechanism of immune suppression by these cells has important clinical implications in the treatment of immune dysfunction after trauma or surgery.
P2X7 Receptors Regulate NKT Cells in Autoimmune Hepatitis
Authors: Kawamura Hiroki , Aswad Fred , Minagawa Masahiro , Govindarajan Sugantha , Dennert Gunther
Published: April 2014

Adenine nucleotides induce danger signals in T cells via purinergic receptors, raising the question whether they exert similar effects on innate immunity. Here we show that micromolar concentrations of nicotinamide adenine dinucleotide (NAD) induce a rapid increase of annexin V staining in NKT cells in vitro, a response that requires expression of P2X7Rs. Consistent with this result, treatment of mice with NAD causes a temporary decrease of NKT cells in the liver and protects from Con A- and α-galactosylceramide-induced hepatitis, both of which require functional NKT cells. Resistance to liver injury is associated with decreased cytokine production by NKT cells in NAD-treated mice. In contrast, when NAD is injected into Con A- or α-galactosylceramide-primed mice, liver injury is exacerbated and cytokine production by NKT cells is increased. This effect is caused by P2X7R-mediated stimulation of activated NKT cells. In agreement, mice lacking P2X7Rs on lymphocytes suffer reduced liver injury, and animals lacking ADP-ribosyltransferase, the enzyme that uses NAD to attach ADP-ribosyl groups to cell surfaces, are also resistant to Con A-induced hepatitis. These results prompt the conclusion that engagement of P2X7Rs on NKT cells inhibits naive, while stimulating activated cells, resulting in suppression or stimulation of autoimmune hepatitis.
Developmental Alterations in Thymocyte Sensitivity Are Actively Regulated by MHC Class II Expression in the Thymic Medulla
Authors: Eck Steven C. , Zhu Peimin , Pepper Marion , Bensinger Steven J. , Freedman Bruce D. , Laufer Terri M.
Published: April 2014

Developing thymocytes are positively selected if they respond to self-MHC-peptide complexes, yet mature T cells are not activated by those same self-complexes. To avoid autoimmunity, positive selection must be followed by a period of maturation when the cellular response to TCR signals is altered. The mechanisms that mediate this postselection developmental tuning remain largely unknown. Specifically, it is unknown whether developmental tuning is a preprogrammed outcome of positive selection or if it is sensitive to ongoing interactions between the thymocyte and the thymic stroma. We probed the requirement for MHC class II-TCR interactions in postselection maturation by studying single positive (SP) CD4 thymocytes from K14/Aβb mice, in which CD4 T cells cannot interact with MHC class II in the thymic medulla. We report here that SP CD4 thymocytes must receive MHC class II signals to avoid hyperactive responses to TCR signals. This hyperactivity correlates with decreased expression of CD5; however, developmental tuning can occur independently of CD5, correlating instead with differences in the distribution of Lck. Thus, the maturation of postselection SP CD4 thymocytes is an active process mediated by ongoing interactions between the T cell and MHC class II molecules. This represents a novel mechanism by which the thymic medulla prevents autoreactivity.
CCL5 Modulates Pneumococcal Immunity and Carriage
Authors: Palaniappan Ravichandran , Singh Shailesh , Singh Udai P. , Singh Rajesh , Ades Edwin W. , Briles David E. , Hollingshead Susan K. , Royal Walter , Sampson Jacquelyn S. , Stiles Jonathan K. , Taub Dennis D. , Lillard James W.
Published: April 2014

Understanding the requirements for protection against pneumococcal carriage and pneumonia will greatly benefit efforts in controlling these diseases. Recently, it has been shown that genetic polymorphisms can result in diminished expression of CCL5, which results in increased susceptibility to and progression of infectious diseases. We show that CCL5, together with Th cytokine mRNA expression, is temporally up-regulated during pneumococcal carriage. To determine the contribution of CCL5 to pneumococcal surface antigen A-specific humoral and cellular pneumococcal immunity, mice were treated with anti-CCL5 or control Abs before and during Streptococcus pneumoniae strain EF3030-challenge for the initiation of carriage. CCL5 blockade resulted in a decrease of CD4+ and CD8+ T cells as well as CD11b+ cells in the spleen, cervical lymph node, lung, and nasopharyngeal associated lymphoid tissue during the recognition phase of the pneumococcal adaptive immune response. CCL5 blockade significantly reduced the Ag-specific IgG2a and IgG1 Abs in serum and IgA Ab levels in nasal washes. These decreases also corresponded to reductions in Ag-specific T cell (mucosal and systemic) responses. CCL5 inhibition resulted in decreasing the quantity of IL-4- and IFN-γ-secreting CD4+ T cells and increasing the number of Ag-specific IL-10-producing CD4+ T cells; these changes combined also corresponded with the transition from pneumococcal carriage to lethal pneumonia. These data suggest that CCL5 is an essential factor for the induction and maintenance of protective pneumococcal immunity.
B Cell-Specific Deficiency for Smad2 In Vivo Leads to Defects in TGF-β-Directed IgA Switching and Changes in B Cell Fate
Authors: Klein Jörg , Ju Wenjun , Heyer Jörg , Wittek Britta , Haneke Torsten , Knaus Petra , Kucherlapati Raju , Böttinger Erwin P. , Nitschke Lars , Kneitz Burkhard
Published: April 2014

Smad2 is a member of the intracellular mediators that transduce signals from TGF-β receptors and activin receptors. Targeted inactivation of Smad2 in mice leads to early lethality before gastrulation. It was shown previously that TGF-βRII deficiency in vivo leads to defects in B cell homeostasis, Ag responsiveness, and IgA class switch recombination of B cells. To investigate the importance of Smad2-mediated signaling in B lymphocytes, we generated a B cell-specific inactivation of Smad2 in mice (bSmad2−/−). bSmad2−/− mice had normal B cell numbers in the spleen but showed a reduced population of marginal zone B cells. In contrast, B cells in Peyer’s patches and peritoneal B-1a cells of bSmad2−/− mice were increased in numbers. bSmad2−/− mice showed a reduced number of surface-IgA+ B cells and of IgA-secreting cells in Peyer’s patches, decreased levels of IgA in serum, and, after immunization with a T cell-dependent Ag, a reduced IgA response. Class switch recombination to IgA was impaired in Smad2-deficient B cells, when stimulated in vitro with LPS in the presence of TGF-β. The growth-inhibitory effects of TGF-β in LPS-stimulated B cells were not affected in Smad2-deficient B cells. In summary, our data indicate a crucial role of Smad2 in mediating signals for the TGF-β-directed class switch to IgA and the induction of IgA responses in vivo. Other B cell functions like growth-inhibitory signaling, which are known to be regulated by signals via the TGF-βR, are not affected in Smad2-deficient B cells.
CD161 (Human NKR-P1A) Signaling in NK Cells Involves the Activation of Acid Sphingomyelinase
Authors: Pozo David , Valés-Gómez Mar , Mavaddat Nasim , Williamson Sharon C. , Chisholm Susan E. , Reyburn Hugh
Published: April 2014

NK and NKT cells play a major role in both innate immunity and in influencing the development of adaptive immune responses. CD161 (human NKR-P1A), a protein encoded in the NK gene complex, is a major phenotypic marker of both these cell types and is thought to be involved in the regulation of NK and NKT cell function. However, the mechanisms of action and signaling pathways of CD161 are poorly understood. To identify molecules able to interact with the cytoplasmic tail of human CD161 (NKR-P1A), we have conducted a yeast two-hybrid screen and identified acid sphingomyelinase as a novel intracellular signaling pathway linked to CD161. mAb-mediated cross-linking of CD161, in both transfectants and primary human NK cells, triggers the activation of acid, but not neutral sphingomyelinase. The sphingomyelinases represent the catabolic pathway for N-acyl-sphingosine (ceramide) generation, an emerging second messenger with key roles in the induction of apoptosis, proliferation, and differentiation. These data therefore define a novel signal transduction pathway for the CD161 (NKR-P1A) receptor and provide fresh insights into NK and NKT cell biology.
Functional Hierarchy of the N-Terminal Tyrosines of SLP-76
Authors: Jordan Martha S. , Sadler Jeffrey , Austin Jessica E. , Finkelstein Lisa D. , Singer Andrew L. , Schwartzberg Pamela L. , Koretzky Gary A.
Published: April 2014

The adaptor protein Src homology 2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76) plays a central role in T cell activation and T cell development. SLP-76 has three functional modules: an acidic domain with three key tyrosines, a central proline-rich domain, and a C-terminal Src homology 2 domain. Of these, mutation of the three N-terminal tyrosines (Y112, Y128, and Y145) results in the most profound effects on T cell development and function. Y112 and Y128 associate with Vav and Nck, two proteins shown to be important for TCR-induced phosphorylation of proximal signaling substrates, Ca2+ flux, and actin reorganization. Y145 has been shown to be important for optimal association of SLP-76 with inducible tyrosine kinase, a key regulator of T cell function. To investigate further the role of the phosphorylatable tyrosines of SLP-76 in TCR signaling, cell lines and primary T cells expressing SLP-76 with mutations in individual or paired tyrosine residues were analyzed. These studies show that Tyr145 of SLP-76 is the most critical tyrosine for both T cell function in vitro and T cell development in vivo.
Modulation of the TLR-Mediated Inflammatory Response by the Endogenous Human Host Defense Peptide LL-37
Authors: Mookherjee Neeloffer , Brown Kelly L. , Bowdish Dawn M. E. , Doria Silvana , Falsafi Reza , Hokamp Karsten , Roche Fiona M. , Mu Ruixia , Doho Gregory H. , Pistolic Jelena , Powers Jon-Paul , Bryan Jenny , Brinkman Fiona S. L. , Hancock Robert E. W.
Published: April 2014

The sole human cathelicidin peptide, LL-37, has been demonstrated to protect animals against endotoxemia/sepsis. Low, physiological concentrations of LL-37 (≤1 μg/ml) were able to modulate inflammatory responses by inhibiting the release of the proinflammatory cytokine TNF-α in LPS-stimulated human monocytic cells. Microarray studies established a temporal transcriptional profile and identified differentially expressed genes in LPS-stimulated monocytes in the presence or absence of LL-37. LL-37 significantly inhibited the expression of specific proinflammatory genes up-regulated by NF-κB in the presence of LPS, including NFκB1 (p105/p50) and TNF-α-induced protein 2 (TNFAIP2). In contrast, LL-37 did not significantly inhibit LPS-induced genes that antagonize inflammation, such as TNF-α-induced protein 3 (TNFAIP3) and the NF-κB inhibitor, NFκBIA, or certain chemokine genes that are classically considered proinflammatory. Nuclear translocation, in LPS-treated cells, of the NF-κB subunits p50 and p65 was reduced ≥50% in the presence of LL-37, demonstrating that the peptide altered gene expression in part by acting directly on the TLR-to-NF-κB pathway. LL-37 almost completely prevented the release of TNF-α and other cytokines by human PBMC following stimulation with LPS and other TLR2/4 and TLR9 agonists, but not with cytokines TNF-α or IL-1β. Biochemical and inhibitor studies were consistent with a model whereby LL-37 modulated the inflammatory response to LPS/endotoxin and other agonists of TLR by a complex mechanism involving multiple points of intervention. We propose that the natural human host defense peptide LL-37 plays roles in the delicate balancing of inflammatory responses in homeostasis as well as in combating sepsis induced by certain TLR agonists.
Transepithelial Pathogen Uptake into the Small Intestinal Lamina Propria
Authors: Vallon-Eberhard Alexandra , Landsman Limor , Yogev Nir , Verrier Bernard , Jung Steffen
Published: April 2014

The lamina propria that underlies and stabilizes the gut lining epithelium is densely populated with strategically located mononuclear phagocytes. Collectively, these lamina propria macrophages and dendritic cells (DC) are believed to be crucial for tissue homeostasis as well as the innate and adaptive host defense. Lamina propria DC were recently shown to gain direct access to the intestinal lumen by virtue of epithelium-penetrating dendrites. However, the role of these structures in pathogen uptake remains under debate. In this study, we report that entry of a noninvasive model pathogen (Aspergillus fumigatus conidia) into the murine small intestinal lamina propria persists in the absence of either transepithelial dendrites or lamina propria DC and macrophages. Our results suggest the existence of multiple pathogen entry pathways and point at the importance of villus M cells in the uptake of gut lumen Ags. Interestingly, transepithelial dendrites seem altogether absent from the small intestine of BALB/c mice suggesting that the function of lamina propria DC extensions resides in their potential selectivity for luminal Ags, rather than in general uptake or gut homeostasis.
Cutting Edge: IL-4-Induced Protection of CD4+CD25− Th Cells from CD4+CD25+ Regulatory T Cell-Mediated Suppression
Authors: Pace Luigia , Rizzo Stefania , Palombi Cecilia , Brombacher Frank , Doria Gino
Published: April 2014

CD4+CD25+ T regulatory (Treg) cells are a CD4+ T cell subset involved in the control of the immune response. In vitro, murine CD4+CD25+ Treg cells inhibit CD4+CD25− Th cell proliferation induced by anti-CD3 mAb in the presence of APCs. The addition of IL-4 to cocultured cells inhibits CD4+CD25+ Treg cell-mediated suppression. Since all cell types used in the coculture express the IL-4Rα chain, we used different combinations of CD4+CD25− Th cells, CD4+CD25+ Treg cells, and APCs from wild-type IL-4Rα+/+ or knockout IL-4Rα−/− mice. Results show that the engagement of the IL-4Rα chain on CD4+CD25− Th cells renders these cells resistant to suppression. Moreover, the addition of IL-4 promotes proliferation of IL-4Rα+/+CD4+CD25+ Treg cells, which preserve full suppressive competence. These findings support an essential role of IL-4 signaling for CD4+CD25− Th cell activation and indicate that IL-4-induced proliferation of CD4+CD25+ Treg cells is compatible with their suppressive activity.
Dominant Tolerance to Kidney Allografts Induced by Anti-Donor MHC Class II Antibodies: Cooperation between T and Non-T CD103+ Cells
Authors: Degauque Nicolas , Lair David , Dupont Alexandre , Moreau Anne , Roussey Gwénaelle , Moizant Frédérique , Hubert François Xavier , Louvet Cédric , Hill Marcelo , Haspot Fabienne , Josien Régis , Usal Claire , Vanhove Bernard , Soulillou Jean Paul , Brouard Sophie
Published: April 2014

Allograft acceptance can be induced in the rat by pretransplant infusion of donor blood or spleen cells. Although promoting long-term acceptance, this treatment is also associated with chronic rejection. In this study, we show that a single administration of anti-donor MHC class II alloimmune serum on the day of transplantation results in indefinite survival of a MHC-mismatched kidney graft. Long-term recipients accept a donor-type skin graft and display no histological evidence of chronic rejection. The kidney grafts of tolerant animals display an accumulation of TCR Cβ, FoxP3, and IDO transcripts. Moreover, as compared with syngeneic recipients, tolerant recipients harbor a large infiltrate of MHC class II+ cells and CD103+ cells. In vitro, splenocytes from tolerant recipients exhibit decreased donor-specific proliferation, which is restored by depletion of non-T cells and partially restored by the blockade of IDO. Finally, splenocytes from tolerant recipients, but not purified T cell splenocytes, transfer donor-specific infectious tolerance without chronic rejection, after infusion into naive recipients, over two generations. However, splenocytes depleted of T cells or splenocytes depleted of CD103+ cells fail to transfer tolerance. Collectively, these data show that a single administration of anti-donor MHC class II alloimmune serum induces a tolerant state characterized by an infiltration of the kidney graft by regulatory T cells and CD103+ cells. These data also show that the transfer of tolerance requires the presence of both T cells and CD103+ dendritic cells. The precise mechanism of cooperation of these two cell subsets remains to be defined.
Downstream of Tyrosine Kinases-1 and Src Homology 2-Containing Inositol 5′-Phosphatase Are Required for Regulation of CD4+CD25+ T Cell Development
Authors: Kashiwada Masaki , Cattoretti Giorgio , McKeag Lisa , Rouse Todd , Showalter Brian M. , Al-Alem Umaima , Niki Masaru , Pandolfi Pier Paolo , Field Elizabeth H. , Rothman Paul B.
Published: April 2014

The adaptor protein, downstream of tyrosine kinases-1 (Dok-1), and the phosphatase SHIP are both tyrosine phosphorylated in response to T cell stimulation. However, a function for these molecules in T cell development has not been defined. To clarify the role of Dok-1 and SHIP in T cell development in vivo, we compared the T cell phenotype of wild-type, Dok-1 knockout (KO), SHIP KO, and Dok-1/SHIP double-knockout (DKO) mice. Dok-1/SHIP DKO mice were runted and had a shorter life span compared with either Dok-1 KO or SHIP KO mice. Thymocyte numbers from Dok-1/SHIP DKO mice were reduced by 90%. Surface expression of both CD25 and CD69 was elevated on freshly isolated splenic CD4+ T cells from SHIP KO and Dok-1/SHIP DKO, suggesting these cells were constitutively activated. However, these T cells did not proliferate or produce IL-2 after stimulation. Interestingly, the CD4+ T cells from SHIP KO and Dok-1/SHIP DKO mice produced higher levels of TGF-β, expressed Foxp3, and inhibited IL-2 production by CD3-stimulated CD4+CD25− T cells in vitro. These findings suggest Dok-1 and SHIP function in pathways that influence regulatory T cell development.
EphA Receptors Inhibit Anti-CD3-Induced Apoptosis in Thymocytes
Authors: Freywald Andrew , Sharfe Nigel , Miller Charlotte D’E. , Rashotte Cher , Roifman Chaim M.
Published: April 2014

The EphA receptor tyrosine kinases interact with membrane-bound ligands of the ephrin-A subfamily. Interaction induces EphA receptor oligomerization, tyrosine phosphorylation, and, as a result, EphA receptor signaling. EphA receptors have been shown to regulate cell survival, migration, and cell-cell and cell-matrix interactions. However, their functions in lymphoid cells are only beginning to be described. We show in this study that functional EphA receptors are expressed by murine thymocytes, including CD4+CD8+, CD4+CD8−, and CD4−CD8+ subpopulations. We demonstrate that activation of EphA receptors by the ephrin-A1 ligand inhibits the anti-CD3-induced apoptosis of CD4+CD8+ double-positive thymocytes. Furthermore, ephrin-A1 costimulation suppresses up-regulation of both the IL-2R α-chain (CD25) and early activation Ag CD69 and can block IL-2 production by CD4+ single-positive cells. In agreement, EphA receptor activation in thymocytes also inhibits TCR-induced activation of the Ras-MAPK pathway. Our findings suggest that EphA receptor activation is antithetical to TCR signaling in thymocytes, and that the level of engagement by ephrin-A proteins on thymic APCs regulates thymocyte selection.
Spatial and Temporal Profiles for Anti-Inflammatory Gene Expression in Leukocytes during a Resolving Model of Peritonitis
Authors: Damazo Amilcar S. , Yona Simon , Flower Roderick J. , Perretti Mauro , Oliani Sonia M.
Published: April 2014

The recent appreciation of the role played by endogenous counterregulatory mechanisms in controlling the outcome of the host inflammatory response requires specific analysis of their spatial and temporal profiles. In this study, we have focused on the glucocorticoid-regulated anti-inflammatory mediator annexin 1. Induction of peritonitis in wild-type mice rapidly (4 h) produced the expected signs of inflammation, including marked activation of resident cells (e.g., mast cells), migration of blood-borne leukocytes, mirrored by blood neutrophilia. These changes subsided after 48–96 h. In annexin 1null mice, the peritonitis response was exaggerated (∼40% at 4 h), with increased granulocyte migration and cytokine production. In blood leukocytes, annexin 1 gene expression was activated at 4, but not 24, h postzymosan, whereas protein levels were increased at both time points. Locally, endothelial and mast cell annexin 1 gene expression was not detectable in basal conditions, whereas it was switched on during the inflammatory response. The significance of annexin 1 system plasticity in the anti-inflammatory properties of dexamethasone was assessed. Clear induction of annexin 1 gene in response to dexamethasone treatment was evident in the circulating and migrated leukocytes, and in connective tissue mast cells; this was associated with the steroid failure to inhibit leukocyte trafficking, cytokine synthesis, and mast cell degranulation in the annexin 1null mouse. In conclusion, understanding how inflammation is brought under control will help clarify the complex interplay between pro- and anti-inflammatory pathways operating during the host response to injury and infection.
CSMD1 Is a Novel Multiple Domain Complement-Regulatory Protein Highly Expressed in the Central Nervous System and Epithelial Tissues
Authors: Kraus Damian M. , Elliott Gary S. , Chute Hilary , Horan Thomas , Pfenninger Karl H. , Sanford Staci D. , Foster Stephen , Scully Sheila , Welcher Andrew A. , Holers V. Michael
Published: April 2014

In this study, we describe the identification and in vitro functional activity of a novel multiple domain complement regulatory protein discovered based on its homology to short consensus repeat (SCR)-containing proteins of the regulators of complement activation (RCA) gene family. The rat cDNA encodes a predicted 388-kDa protein consisting of 14 N-terminal CUB domains that are separated from each other by a SCR followed by 15 tandem SCR domains, a transmembrane domain, and a short cytoplasmic tail. This protein is the homolog of the human protein of unknown function called the CUB and sushi multiple domains 1 (CSMD1) protein. A cloning strategy that incorporates the two C-terminal CUB-SCR domains and 12 of the tandem SCR repeats was used to produce a soluble rat CSMD1 protein. This protein blocked classical complement pathway activation in a comparable fashion with rat Crry but did not block alternative pathway activation. Analysis of CSMD1 mRNA expression by in situ hybridization and immunolabeling of neurons indicates that the primary sites of synthesis are the developing CNS and epithelial tissues. Of particular significance is the enrichment of CSMD1 in the nerve growth cone, the amoeboid-leading edge of the growing neuron. These results suggest that CSMD1 may be an important regulator of complement activation and inflammation in the developing CNS, and that it may also play a role in the context of growth cone function.
Cutting Edge: Inhibition of the Retinoid X Receptor (RXR) Blocks T Helper 2 Differentiation and Prevents Allergic Lung Inflammation
Authors: Grenningloh Roland , Gho Andrea , di Lucia Pietro , Klaus Michael , Bollag Werner , Ho I-Cheng , Sinigaglia Francesco , Panina-Bordignon Paola
Published: April 2014

Among the many factors regulating Th cell differentiation, some nuclear hormone receptors are emerging as important players. The retinoid X receptor (RXR) functions as heterodimerization partner for a variety of nuclear hormone receptors. We show in this study that RXR is critical for Th2-mediated immunity. An RXR antagonist inhibited Th2 differentiation, resulting in reduced production of IL-4, IL-10, and IL-13, whereas IFN-γ production was enhanced. This effect was dependent on the presence of APCs. In addition, IL-5 production was blocked directly in Th cells. In vivo, inhibition of RXR prevented experimentally induced allergic lung inflammation. Th1-mediated inflammation was not affected. Its specific role in Th2-mediated inflammation makes RXR a promising target for the development of therapies against diseases such as allergic asthma and atopic dermatitis.
Detection and Characterization of Hemopoietic Stem Cells in the Adult Human Small Intestine
Authors: Lynch Lydia , O’Donoghue Diarmuid , Dean Jonathan , O’Sullivan Jacintha , O’Farrelly Cliona , Golden-Mason Lucy
Published: April 2014

The concept of lymphoid differentiation in the human gastrointestinal tract is controversial but is the focus of this study, which examined adult human small intestinal tissue for the presence of CD34+CD45+ hemopoietic stem cells (HSCs) and lymphoid progenitors. Flow cytometry demonstrated that over 5% of leukocytes (CD45+ cells) isolated from human gut were HSCs coexpressing CD34, a significantly higher incidence than in matched peripheral blood or control bone marrow. HSCs were detected in cell preparations from both the epithelium and lamina propria of all samples tested and localized to the intestinal villous and crypt regions using immunofluorescence. A high proportion of gut HSCs expressed the activation marker CD45RA, and few expressed c-kit, indicating ongoing differentiation. The vast majority of intestinal HSCs coexpressed the T cell Ag, CD7 (92% in the epithelium, 80% in the lamina propria) whereas <10% coexpressed the myeloid Ag CD33, suggesting that gut HSCs are a relatively mature population committed to the lymphoid lineage. Interestingly, almost 50% of epithelial layer HSCs coexpressed CD56, the NK cell Ag, compared with only 10% of the lamina propria HSC population, suggesting that the epithelium may be a preferential site of NKR+ lymphoid differentiation. In contrast, bone marrow HSCs displayed low coexpression of CD56 and CD7 but high coexpression of CD33. The phenotype of intestinal HSCs, which differs significantly from circulating or bone marrow HSCs, is consistent with a role in local lymphoid development.
Notch Signaling Requires GATA-2 to Inhibit Myelopoiesis from Embryonic Stem Cells and Primary Hemopoietic Progenitors
Authors: de Pooter Renée F. , Schmitt Thomas M. , de la Pompa José Luis , Fujiwara Yuko , Orkin Stuart H. , Zúñiga-Pflücker Juan Carlos
Published: April 2014

The bone marrow and thymus, although both hemopoietic environments, induce very distinct differentiation outcomes. The former supports hemopoietic stem cell self-renewal and multiple hemopoietic lineages, while the latter supports T lymphopoiesis almost exclusively. This distinction suggests that the thymic environment acts to restrict the hemopoietic fates available to thymic immigrants. In this study, we demonstrate that the addition of the Notch ligand Delta-like-1 (Dll-1) to an in vitro system that otherwise supports myelopoiesis, greatly reduces the myelopoietic potential of stem cells or uncommitted progenitors. In contrast, committed myeloid progenitors mature regardless of the presence of Dll-1. The block in myelopoiesis is the direct result of Notch signaling within the hemopoietic progenitor, and Dll-1-induced signals cause a rapid increase in the expression of the zinc finger transcription factor GATA-2. Importantly, in the absence of GATA-2, Dll-1-induced signals fail to inhibit commitment to the myeloid fate. Taken together, our results support a role for GATA-2 in allowing Dll-1 to restrict non-T cell lineage differentiation outcomes.
Statin-Induced Proinflammatory Response in Mitogen-Activated Peripheral Blood Mononuclear Cells through the Activation of Caspase-1 and IL-18 Secretion in Monocytes
Authors: Coward William R. , Marei Ayman , Yang AiLi , Vasa-Nicotera Mariuca M. , Chow Sek C.
Published: April 2014

Statins, which inhibit 3-hydroxy-3-methylglutaryl CoA reductase, have been shown recently to promote proinflammatory responses. We show in this study that both atorvastatin and simvastatin induced proinflammatory responses in mitogen-activated PBMCs by increasing the number of T cells secreting IFN-γ. This is abolished by the presence of mevalonate, suggesting that statins act specifically by blocking the mevalonate pathway for cholesterol synthesis to promote the proinflammatory response. Both statins at low concentrations induced a dose-dependent increase in the number of IFN-γ-secreting T cells in mitogen-activated PBMCs, whereas at higher concentrations the effect was abolished. The proinflammatory effect of statins was not seen in purified T cells per se activated with mitogen. However, conditioned medium derived from statin-treated PBMCs enhanced the number of IFN-γ-secreting cells in activated purified T cells. This effect was not blocked by mevalonate, but was abolished by neutralizing Abs to IL-18 and IL-12. Similarly, the up-regulation of IFN-γ-secreting T cells in PBMCs costimulated with statins and mitogens was blocked by the neutralizing anti-IL-18 and anti-IL-12. We showed that simvastatin stimulates the secretion of IL-18 and IL-1β in monocytes. Active caspase-1, which is required for the processing and secretion of IL-18 and IL-1β, was activated in simvastatin-treated monocytes. This was blocked by mevalonate and the caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone. Taken together, the proinflammatory response mediated by statins in activated PBMCs is mediated mainly via the activation of caspase-1 and IL-18 secretion in the monocytes and to a lesser extent by IL-12.
Preservation of Functional Virus-Specific Memory CD8+ T Lymphocytes in Vaccinated, Simian Human Immunodeficiency Virus-Infected Rhesus Monkeys
Authors: Acierno Paula M. , Schmitz Jörn E. , Gorgone Darci A. , Sun Yue , Santra Sampa , Seaman Michael S. , Newberg Michael H. , Mascola John R. , Nabel Gary J. , Panicali Dennis , Letvin Norman L.
Published: April 2014

Functional impairment of virus-specific memory CD8+ T lymphocytes has been associated with clinical disease progression following HIV, SIV, and simian human immunodeficiency virus infection. These lymphocytes have a reduced capacity to produce antiviral cytokines and mediators involved in the lysis of virally infected cells. In the present study, we used polychromatic flow cytometry to assess the frequency and functional capacity of central memory (CD28+CD95+) and effector memory (CD28−CD95+) subpopulations of Gag-specific CD8+ T cells in SIV/simian human immunodeficiency virus-infected rhesus monkeys. The aim of this study was to determine whether Ag-specific, memory CD8+ T cell function could be preserved in infected monkeys that had been immunized before infection with a vaccine regimen consisting of a plasmid DNA prime followed by a recombinant viral vector boost. We observed that vaccination was associated with the preservation of Gag-specific central memory CD8+ T cells that were functionally capable of producing IFN-γ, and effector memory CD8+ T cells that were capable of producing granzyme B following viral Ag exposure.
The Autoimmune Diabetes LocusIdd9Regulates Development of Type 1 Diabetes by Affecting the Homing of Islet-Specific T Cells
Authors: Waldner Hanspeter , Sobel Raymond A. , Price Nichole , Kuchroo Vijay K.
Published: April 2014

Several genetic insulin-dependent diabetes (Idd) intervals that confer resistance to autoimmune diabetes have been identified in mice and humans, but the mechanisms by which they protect against development of diabetes have not been elucidated. To determine the effect of Idd9 on the function of islet-specific T cells, we established novel BDC-Idd9 mice that harbor BDC2.5 TCR transgenic T cells containing the Idd9 of diabetes-resistant B10 mice. We show that the development and functional responses of islet-specific T cells from BDC-Idd9 mice are not defective compared with those from BDC mice, which contain the Idd9 of diabetes-susceptible NOD mice. Upon transfer, BDC T cells rapidly induced severe insulitis and diabetes in NOD.scid mice, whereas those from BDC-Idd9 mice mediated a milder insulitis and induced diabetes with a significantly delayed onset. BDC and BDC-Idd9 T cells expanded comparably in recipient mice. However, BDC-Idd9 T cells accumulated in splenic periarteriolar lymphatic sheaths, whereas BDC T cells were mainly found in pancreatic lymph nodes and pancreata of recipients, indicating that the transferred T cells differed in their homing. We provide evidence that the migration pattern of transferred BDC and BDC-Idd9 T cells at least partly depends on their differential chemotaxis toward the CCR7 ligand CCL19. Taken together, our data show that the Idd9 locus regulates development of type 1 diabetes by affecting the homing of islet-specific T cells.
TAT-BH4 and TAT-Bcl-xL Peptides Protect against Sepsis-Induced Lymphocyte Apoptosis In Vivo
Authors: Hotchkiss Richard S. , McConnell Kevin W. , Bullok Kristin , Davis Christopher G. , Chang Katherine C. , Schwulst Steven J. , Dunne Jeffrey C. , Dietz Gunnar P. H. , Bähr Mathias , McDunn Jonathan E. , Karl Irene E. , Wagner Tracey H. , Cobb J. Perren , Coopersmith Craig M. , Piwnica-Worms David
Published: April 2014

Apoptosis is a key pathogenic mechanism in sepsis that induces extensive death of lymphocytes and dendritic cells, thereby contributing to the immunosuppression that characterizes the septic disorder. Numerous animal studies indicate that prevention of apoptosis in sepsis improves survival and may represent a potential therapy for this highly lethal disorder. Recently, novel cell-penetrating peptide constructs such as HIV-1 TAT basic domain and related peptides have been developed to deliver bioactive cargoes and peptides into cells. In the present study, we investigated the effects of sepsis-induced apoptosis in Bcl-xL transgenic mice and in wild-type mice treated with an antiapoptotic TAT-Bcl-xL fusion protein and TAT-BH4 peptide. Lymphocytes from Bcl-xL transgenic mice were resistant to sepsis-induced apoptosis, and these mice had a ∼3-fold improvement in survival. TAT-Bcl-xL and TAT-BH4 prevented Escherichia coli-induced human lymphocyte apoptosis ex vivo and markedly decreased lymphocyte apoptosis in an in vivo mouse model of sepsis. In conclusion, TAT-conjugated antiapoptotic Bcl-2-like peptides may offer a novel therapy to prevent apoptosis in sepsis and improve survival.
Differential Requirements of T Cell Subsets for CD40 Costimulation in Immunity to Blastomyces dermatitidis
Authors: Wüthrich Marcel , Fisette Phil L. , Filutowicz Hanna I. , Klein Bruce S.
Published: April 2014

Cell-mediated immunity and production of type 1 cytokines are the main defenses against pathogenic fungi. Ligation of CD40 by CD40L on T cells is critical for the induction of these immune responses in vivo. We explored the role of CD40/CD40L interactions in vaccine immunity to Blastomyces dermatitidis by immunizing CD40−/− and CD40L−/− mice and analyzing their resistance to reinfection in a murine pulmonary model. In the absence of CD40 or CD40L, CD4+ cells failed to get primed or produce type 1 cytokine and impaired the generation of CD8+ T1 cells. The CD8+ T cell defect was not due to regulatory T cells or impaired APC maturation or Ag presentation to T cells. If CD4+ cells were first eliminated, vaccination of CD40−/− and CD40L−/− mice restored priming of CD8+ cells, type 1 cytokine production, and resistance. Hence, CD4+ and CD8+ cells differ sharply in their requirement for CD40/CD40L interaction during the generation of antifungal immunity. Despite the plasticity of T cell subsets in vaccine immunity, in absence of CD40/CD40L interaction, CD4+ cells may impede the priming of CD8+ cells at the cost of host survival against a lethal infectious disease.
A Critical Role for Adrenomedullin-Calcitonin Receptor-Like Receptor in Regulating Rheumatoid Fibroblast-Like Synoviocyte Apoptosis
Authors: Uzan Benjamin , Ea Hang-Korng , Launay Jean-Marie , Garel Jean-Michel , Champy Romuald , Cressent Michèle , Lioté Frédéric
Published: April 2014

Rheumatoid arthritis (RA) is characterized by fibroblast-like synoviocyte (FLS) hyperplasia, which is partly ascribable to decreased apoptosis. In this study, we show that adrenomedullin (ADM), an antiapoptotic peptide, is constitutively secreted in larger amounts by FLS from joints with RA (RA-FLS) than with osteoarthritis (OA-FLS). ADM secretion was regulated by TNF-α. Peptidylglycine α-amidating monooxygenase, the ADM-processing enzyme, was expressed at the mRNA level by both RA-FLS and OA-FLS. Constituents of the ADM heterodimeric receptor calcitonin receptor-like receptor (CRLR)/receptor activity-modifying protein (RAMP)-2 were up-regulated at the mRNA and protein levels in cultured RA-FLS compared with OA-FLS. ADM induced rapid intracellular cAMP production in FLS and reduced caspase-3 activity, DNA fragmentation, and chromatin condensation in RA-FLS exposed to apoptotic conditions, indicating that CRLR/RAMP-2 was fully functional. ADM-induced cAMP production was less marked in OA-FLS than in RA-FLS, suggesting differences in receptor regulation and expression. ADM dose-dependently inhibited RA-FLS apoptosis, and this effect was reversed by the 22–52 ADM antagonist peptide. ADM inhibited RA-FLS apoptosis triggered by extrinsic and intrinsic pathways. Our data suggest that ADM may prevent or reduce RA-FLS apoptosis, via up-regulation of its functional receptor CRLR/RAMP-2. Regulation of ADM secretion and/or CRLR/RAMP-2 activation may constitute new treatment strategies for RA.
Monocyte and Macrophage Activation by Lipoteichoic Acid Is Independent of Alanine and Is Potentiated by Hemoglobin
Authors: Hasty David L. , Meron-Sudai Shiri , Cox Kathleen H. , Nagorna Tetyana , Ruiz-Bustos Eduardo , Losi Elena , Courtney Harry S. , Mahrous Engy A. , Lee Richard , Ofek Itzhak
Published: April 2014

Lipoteichoic acids (LTAs) are Gram-positive bacterial cell wall components that elicit mononuclear cell cytokine secretion. Cytokine-stimulating activity is thought to be dependent on retaining a high level of ester-linked d-alanine residues along the polyglycerol phosphate backbone. However, Streptococcus pyogenes LTA essentially devoid of d-alanine caused human and mouse cells to secrete as much IL-6 as LTA with a much higher d-alanine content. Furthermore, hemoglobin (Hb) markedly potentiates the stimulatory effect of various LTAs on mouse macrophages or human blood cells, regardless of their d-alanine content. LTA and Hb appear to form a molecular complex, based on the ability of each to affect the other’s migration on native acrylamide gels, their comigration on these gels, and the ability of LTA to alter the absorption spectra of Hb. Because S. pyogenes is known to release LTA and secrete at least two potent hemolytic toxins, LTA-Hb interactions could occur during streptococcal infections and might result in a profound alteration of the local inflammatory response.
Differential Restoration of Myeloid and Plasmacytoid Dendritic Cells in HIV-1-Infected Children after Treatment with Highly Active Antiretroviral Therapy
Authors: Zhang Zheng , Fu Junliang , Zhao Qingxia , He Yun , Jin Lei , Zhang Hui , Yao Jinxia , Zhang Linqi , Wang Fu-Sheng
Published: April 2014

Numerical and functional deficits in myeloid (mDC) and plasmacytoid dendritic cell (pDC) subsets have been found in both adult and pediatric HIV-1 carriers. Whether these impaired DC subsets can be restored after treatment with highly active antiretroviral therapy (HAART) is currently unknown, especially in HIV-1-infected children. In this report, we characterized mDC and pDC subsets in 18 HIV-1-infected children who received HAART treatment and compared them with those in 6 untreated HIV-1-infected children and 27 HIV-1-uninfected healthy children. Among children treated with HAART, 11 were found to suppress HIV-1 replication successfully below the detection limit (HAART-suppressed group) while the remaining 7 failed (HAART-failure group). In HAART-suppressed children, a gradual and complete restoration of the frequency and function of mDCs was observed while the recovery of pDCs was only partial. However, mDC and pDC subsets in HARRT failure children were indistinguishable from the HAART-naive infected children. We also found that mDC frequency and IFN-α-releasing capacity of pDC positively correlated with CD4 T cell percentages in all HIV-1-infected children. In HAART-naive children, the mDC frequency correlated the HIV-1-specific CTL frequency. Our findings suggest that HAART has a differential impact on the restoration of mDC and pDC subsets. These findings may help guide the development of HIV-1-specific immune therapy aimed at fully restoring host immune function in chronically HIV-1-infected children.
STAT3 and NF-κB Signal Pathway Is Required for IL-23-Mediated IL-17 Production in Spontaneous Arthritis Animal Model IL-1 Receptor Antagonist-Deficient Mice
Authors: Cho Mi-La , Kang Jung-Won , Moon Young-Mee , Nam Hyo-Jung , Jhun Joo-Yeon , Heo Seong-Beom , Jin Hyun-Tak , Min So-Youn , Ju Ji-Hyeon , Park Kyung-Su , Cho Young-Gyu , Yoon Chong-Hyeon , Park Sung-Hwan , Sung Young-Chul , Kim Ho-Youn
Published: April 2014

IL-23 is a heterodimeric cytokine composed of a p19 subunit and the p40 subunit of IL-12. IL-23 has proinflammatory activity, inducing IL-17 secretion from activated CD4+ T cells and stimulating the proliferation of memory CD4+ T cells. We investigated the pathogenic role of IL-23 in CD4+ T cells in mice lacking the IL-1R antagonist (IL-1Ra−/−), an animal model of spontaneous arthritis. IL-23 was strongly expressed in the inflamed joints of IL-1Ra−/− mice. Recombinant adenovirus expressing mouse IL-23 (rAd/mIL-23) significantly accelerated this joint inflammation and joint destruction. IL-1β further increased the production of IL-23, which induced IL-17 production and OX40 expression in splenic CD4+ T cells of IL-1Ra−/− mice. Blocking IL-23 with anti-p19 Ab abolished the IL-17 production induced by IL-1 in splenocyte cultures. The process of IL-23-induced IL-17 production in CD4+ T cells was mediated via the activation of Jak2, PI3K/Akt, STAT3, and NF-κB, whereas p38 MAPK and AP-1 did not participate in the process. Our data suggest that IL-23 is a link between IL-1 and IL-17. IL-23 seems to be a central proinflammatory cytokine in the pathogenesis of this IL-1Ra−/− model of spontaneous arthritis. Its intracellular signaling pathway could be useful therapeutic targets in the treatment of autoimmune arthritis.