bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-Sided Roles of IL-27: Induction of Th1 Differentiation on Naive CD4+ T Cells versus Suppression of Proinflammatory Cytokine Production Including IL-23-Induced IL-17 on Activated CD4+ T Cells Partially Through STAT3-Dependent Mechanism
Authors: Yoshimura Takeru , Takeda Atsunobu , Hamano Shinjiro , Miyazaki Yoshiyuki , Kinjyo Ichiko , Ishibashi Tatsuro , Yoshimura Akihiko , Yoshida Hiroki
Published: April 2014

Recent lines of evidence have demonstrated that IL-27, a newly identified IL-12-related cytokine, has two apparently conflicting roles in immune responses: one as an initiator of Th1 responses and the other as an attenuator of inflammatory cytokine production. Although the IL-27-mediated Th1 initiation mechanism has been elucidated, little is known about the molecular basis for the suppression of cytokine production. In the present study, we demonstrated that IL-27 suppressed the production of various proinflammatory cytokines by fully activated CD4+ T cells while it had no effect on the cytokine production by CD4+ T cells at early phases of activation. IL-27 also suppressed IL-17 production by activated CD4+ T cells, thereby counteracting IL-23, another IL-12-related cytokine with proinflammatory effects. In fully activated CD4+ T cells, STAT3 was preferentially activated by IL-27 stimulation, whereas both STAT1 and 3 were activated by IL-27 in early activated CD4+ T cells. Lack of STAT3 in fully activated cells impaired the suppressive effects of IL-27. These data indicated that the preferential activation of STAT3 in fully activated CD4+ T cells plays an important role in the cytokine suppression by IL-27/WSX-1.
Transitional B Cell Fate Is Associated with Developmental Stage-Specific Regulation of Diacylglycerol and Calcium Signaling upon B Cell Receptor Engagement
Authors: Hoek Kristen L. , Antony Pierre , Lowe John , Shinners Nicholas , Sarmah Bhaskarjyoti , Wente Susan R. , Wang Demin , Gerstein Rachel M. , Khan Wasif N.
Published: April 2014

Functional peripheral mature follicular B (FoB) lymphocytes are thought to develop from immature transitional cells in a BCR-dependent manner. We have previously shown that BCR cross-linking in vitro results in death of early transitional (T1) B cells, whereas late transitional (T2) B cells survive and display phenotypic characteristics of mature FoB cells. We now demonstrate that diacylglycerol (DAG), a lipid second messenger implicated in cell survival and differentiation, is produced preferentially in T2 compared with T1 B cells upon BCR cross-linking. Consistently, inositol 1,4,5-triphosphate is also produced preferentially in T2 compared with T1 B cells. Unexpectedly, the initial calcium peak appears similar in both T1 and T2 B cells, whereas sustained calcium levels are higher in T1 B cells. Pretreatment with 2-aminoethoxydiphenylborate, an inhibitor of inositol 1,4,5-triphosphate receptor-mediated calcium release, and verapamil, an inhibitor of L-type calcium channels, preferentially affects T1 B cells, suggesting that distinct mechanisms regulate calcium mobilization in each of the two transitional B cell subsets. Finally, BCR-mediated DAG production is dependent upon Bruton’s tyrosine kinase and phospholipase C-γ2, enzymes required for the development of FoB from T2 B cells. These results suggest that calcium signaling in the absence of DAG-mediated signals may lead to T1 B cell tolerance, whereas the combined action of DAG and calcium signaling is necessary for survival and differentiation of T2 into mature FoB lymphocytes.
The DMα and DMβ Chain Cooperate in the Oxidation and Folding of HLA-DM
Authors: van Lith Marcel , Benham Adam M.
Published: April 2014

HLA-DM (DM) is a heterodimeric MHC molecule that catalyzes the peptide loading of classical MHC class II molecules in the endosomal/lysosomal compartments of APCs. Although the function of DM is well-established, little is known about how DMα and β-chains fold, oxidize, and form a complex in the endoplasmic reticulum (ER). In this study, we show that glycosylation promotes, but is not essential for, DMαβ ER exit. However, glycosylation of DMα N15 is required for oxidation of the α-chain. The DMα and β-chains direct each others fate: single DMα chains cannot fully oxidize without DMβ, while DMβ forms disulfide-linked homodimers without DMα. Correct oxidation and subsequent ER egress depend on the unique DMβ C25 and C35 residues. This suggests that the C25-C35 disulfide bond in the peptide-binding domain overcomes the need for stabilizing peptides required by other MHC molecules.
Lectin Pathway of Bony Fish Complement: Identification of Two Homologs of the Mannose-Binding Lectin Associated with MASP2 in the Common Carp (Cyprinus carpio)
Authors: Nakao Miki , Kajiya Takayuki , Sato Yuho , Somamoto Tomonori , Kato-Unoki Yoko , Matsushita Misao , Nakata Munehiro , Fujita Teizo , Yano Tomoki
Published: April 2014

The lectin pathway of complement is considered to be the most ancient complement pathway as inferred from identification of ancient homologs of mannose-binding lectin (MBL) and MBL-associated serine proteases (MASPs) in some invertebrates. MBL homologs with galactose selectivity and an MASP3-like sequence also occur in bony fish, linking the evolution of the lectin complement pathway from invertebrates to higher vertebrates. However, these cannot be considered authentic complement components until confirmatory functional evidence is obtained. Here, we report the isolation and characterization of two MBL homologs from a cyprinid teleost, the common carp, Cyprinus carpio. One, designated GalBL, corresponds to the MBL-like molecule with the galactose specificity. The other is an authentic MBL with mannose specificity. Both were found to associate with a serine protease that cleaves native human C4 into C4b but not C4i with a hydrolyzed thioester. Molecular cloning and phylogenetic analysis revealed this C4-activating protease to be carp MASP2, indicating that MASP2 arose before the emergence of bony fish. Database mining of MBL-like genes reveals that MBL and GalBL genes are arranged in tandem in the zebrafish genome and that both lectins are conserved in the distantly related puffer fish. These results imply that bony fish have developed a diverged set of MBL homologs that function in the lectin complement pathway.
Mucosal Vaccine Targeting Improves Onset of Mucosal and Systemic Immunity to Botulinum Neurotoxin A
Authors: Maddaloni Massimo , Staats Herman F. , Mierzejewska Dagmara , Hoyt Teri , Robinson Amy , Callis Gayle , Kozaki Shunji , Kiyono Hiroshi , McGhee Jerry R. , Fujihashi Kohtaro , Pascual David W.
Published: April 2014

Absence of suitable mucosal adjuvants for humans prompted us to consider alternative vaccine designs for mucosal immunization. Because adenovirus is adept in binding to the respiratory epithelium, we tested the adenovirus 2 fiber protein (Ad2F) as a potential vaccine-targeting molecule to mediate vaccine uptake. The vaccine component (the host cell-binding domain to botulinum toxin (BoNT) serotype A) was genetically fused to Ad2F to enable epithelial binding. The binding domain for BoNT was selected because it lies within the immunodominant H chain as a β-trefoil (Hcβtre) structure; we hypothesize that induced neutralizing Abs should be protective. Mice were nasally immunized with the Hcβtre or Hcβtre-Ad2F, with or without cholera toxin (CT). Without CT, mice immunized with Hcβtre produced weak secretory IgA (sIgA) and plasma IgG Ab response. Hcβtre-Ad2F-immunized mice produced a sIgA response equivalent to mice coimmunized with CT. With CT, Hcβtre-Ad2F-immunized mice showed a more rapid onset of sIgA and plasma IgG Ab responses that were supported by a mixed Th1/Th2 cells, as opposed to mostly Th2 cells by Hcβtre-dosed mice. Mice immunized with adjuvanted Hcβtre-Ad2F or Hcβtre were protected against lethal BoNT serotype A challenge. Using a mouse neutralization assay, fecal Abs from Hcβtre-Ad2F or Hcβtre plus CT-dosed mice could confer protection. Parenteral immunization showed that the inclusion of Ad2F enhances anti-Hcβtre Ab titers even in the absence of adjuvant. This study shows that the Hcβtre structure can confer protective immunity and that use of Hcβtre-Ad2F gives more rapid and sustained mucosal and plasma Ab responses.
Release of LL-37 by Activated Human Vγ9Vδ2 T Cells: A Microbicidal Weapon against Brucella suis
Authors: Dudal Sherri , Turriere Chrystell , Bessoles Stephanie , Fontes Pascaline , Sanchez Françoise , Liautard Janny , Liautard Jean-Pierre , Lafont Virginie
Published: April 2014

Human Vγ9Vδ2 T cells play a crucial role in early immune response to intracellular pathogens. Moreover, in brucellosis, these cells are drastically increased in the peripheral blood of patients during the acute phase of infection. In vitro, Vγ9Vδ2 T cells are capable of inhibiting Brucella growth and development through a combination of mechanisms: 1) cytotoxicity, 2) macrophage activation and bactericidal activity through cytokine and chemokine secretion, and 3) antibacterial effects. We previously described that antibacterial factors were found in supernatants from activated Vγ9Vδ2 T cells. In this study, we show that Vγ9Vδ2 T cells express the human cathelicidin hCAP18 and its mature form, known as LL-37, is released upon activation of Vγ9Vδ2 T cells. We also show that LL-37 has an antibacterial effect on Brucella suis. Overall, our results demonstrate that LL-37 is a soluble factor responsible for a part of the bactericidal activity of Vγ9Vδ2 T cells.
Differential Modulation of Human Lactoferrin Activity against Both R5 and X4-HIV-1 Adsorption on Epithelial Cells and Dendritic Cells by Natural Antibodies
Authors: Saidi Héla , Eslaphazir Jobin , Carbonneil Cédric , Carthagena Laetitia , Requena Mary , Nassreddine Nadine , Belec Laurent
Published: April 2014

Human lactoferrin (Lf) is an iron binding glycoprotein that is present in several mucosal secretions. Many biological functions have been ascribed to Lf. In the present study, we showed that Lf limited specifically adsorption of R5- and X4-HIV-1-free particles on endometrial epithelial HEC-1A cells, by inhibiting virus adsorption on heparan-sulfated proteoglycans. But, Lf did not interfere with both R5 and X4-HIV transcytosis. We showed also the efficacy of Lf in preventing R5 and X4-HIV capture by dendritic cells. Conversely, we demonstrated that Lf-reacting natural Abs (NAbs) present within i.v. Ig-enhanced HIV attachment on dendritic cells by forming HIV-Lf-NAbs. HIV particles were able to directly interact with Lf following its interaction with NAbs. We also found Lf-reacting natural Abs within cervicovaginal secretions, suggesting the existence of Lf-NAbs complexes in women genital tract in vivo. In conclusion, this study highlights Lf as a potent microbicides and reports new function for NAbs within the genital compartment that may compartment that may abolish the inhibitory activity of microbicide compounds. Thus, we proposed a model in which Lf would appear as a double-edged sword that could have beneficial or detrimental effects depending on both cellular and molecular environments. This study highlights the use of Lf derivates as microbicide candidates to limit such interferences.
Involvement of the Urokinase Kringle Domain in Lipopolysaccharide-Induced Acute Lung Injury
Authors: Wang Xue-Qing , Bdeir Khalil , Yarovoi Sergei , Cines Douglas B. , Fang Wenfeng , Abraham Edward
Published: April 2014

Urokinase plasminogen activator (uPA) plays a major role in fibrinolytic processes and also can potentiate LPS-induced neutrophil activation through interactions with its kringle domain (KD). To investigate the role of the uPA KD in modulating acute inflammatory processes in vivo, we cloned and then developed Abs to the murine uPA KD. Increased pulmonary expression of uPA and the uPA KD was present in the lungs after LPS exposure. Administration of anti-kringle Abs diminished LPS-induced up-regulation of uPA and uPA KD in the lungs, and also decreased the severity of LPS-induced acute lung injury, as determined by development of lung edema, pulmonary neutrophil accumulation, histology, and lung IL-6, MIP-2, and TNF-α cytokine levels. These proinflammatory effects of the uPA KD appeared to be mediated through activation of Akt and NF-κB. The present studies indicate that the uPA KD plays a major role in the development of TLR4-mediated acute inflammatory processes, including lung injury. Blockade of the uPA KD may prevent the development or ameliorate the severity of acute lung injury induced through TLR4-dependent mechanisms, such as would occur in the setting of Gram-negative pulmonary or systemic infection.
Type I IFN Modulates Host Defense and Late Hyperinflammation in Septic Peritonitis
Authors: Weighardt Heike , Kaiser-Moore Simone , Schlautkötter Sylvia , Rossmann-Bloeck Tanja , Schleicher Ulrike , Bogdan Christian , Holzmann Bernhard
Published: April 2014

TLRs are considered important for the control of immune responses during endotoxic shock or polymicrobial sepsis. Signaling by TLRs may proceed through the adapter proteins MyD88 or TIR domain-containing adaptor inducinng IFN-β. Both pathways can lead to the production of type I IFNs (IFN-αβ). In the present study, the role of the type I IFN pathway for host defense and immune pathology in sepsis was investigated using a model of mixed bacterial peritonitis. Systemic levels of IFN-αβ protein were markedly elevated during septic peritonitis. More detailed analyses revealed production of IFN-β, but not IFN-α subtypes, and identified CD11b+CD11c− macrophage-like cells as major producers of IFN-β. The results further demonstrate that in IFN-αβ receptor I chain (IFNARI)-deficient mice, the early recruitment of neutrophils to the infected peritoneal cavity was augmented, most likely due to an increased local production of MCP-1 and leukotriene B4. In the absence of IFNARI, peritoneal neutrophils also exhibited enhanced production of reactive oxygen intermediates and elevated expression of Mac-1. Conversely, administration of recombinant IFN-β resulted in reduced leukotriene B4 levels and decreased peritoneal neutrophil recruitment and activation. Analysis of the cytokine response to septic peritonitis revealed that IFNARI deficiency strongly attenuated late, but not early, hyperinflammation. In accordance with these findings, bacterial clearance and overall survival of IFNARI−/− mice were improved. Therefore, the present study reveals critical functions of the type I IFN pathway during severe mixed bacterial infections leading to sepsis. The results suggest that type I IFN exerts predominantly adverse effects under these conditions.
Induction of IL-10 Suppressors in Lung Transplant Patients by CD4+25+ Regulatory T Cells through CTLA-4 Signaling
Authors: Bharat Ankit , Fields Ryan C. , Trulock Elbert P. , Patterson G. Alexander , Mohanakumar Thalachallour
Published: April 2014

T cell-mediated autoimmunity to collagen V (col-V), a sequestered yet immunogenic self-protein, can induce chronic lung allograft rejection in rodent models. In this study we characterized the role of CD4+CD25+ regulatory T cells (Tregs) in regulating col-V autoimmunity in human lung transplant (LT) recipients. LT recipients revealed a high frequency of col-V-reactive, IL-10-producing CD4+ T cells (TIL-10 cells) with low IL-2-, IFN-γ-, IL-5-, and no IL-4-producing T cells. These TIL-10 cells were distinct from Tregs because they lacked constitutive expression of both CD25 and Foxp3. Expansion of TIL-10 cells during col-V stimulation in vitro involved CTLA-4 on Tregs, because both depleting and blocking Tregs with anti-CTLA4 F(ab′)2 mAbs resulted in loss of TIL-10 cells with a concomitant increase in IFN-γ producing Th1 cells (TIFN-γ cells). A Transwell culture of col-V-specific TIL-10 cells with Th1 cells (those generated in absence of Tregs) from the same patient resulted in marked inhibition of IFN-γ and proliferation of TIFN-γ cells, which was reversed by neutralizing IL-10. Furthermore, the TIL-10 cells were HLA class II restricted because blocking HLA class II on APCs resulted in the loss of IL-10 production. Chronic lung allograft rejection was associated with the loss of Tregs with a concomitant decrease in TIL-10 cells and an increase in TIFN-γ cells. We conclude that LT patients have col-V-specific T cells that can be detected in the peripheral blood. The predominant col-V-specific T cells produce IL-10 that suppresses autoreactive Th1 cells independently of direct cellular contact. Tregs are pivotal for the induction of these “suppressor” TIL-10 cells.
Reinstalling Antitumor Immunity by Inhibiting Tumor-Derived Immunosuppressive Molecule IDO through RNA Interference
Authors: Zheng Xiufen , Koropatnick James , Li Mu , Zhang Xusheng , Ling Fengjun , Ren Xiubao , Hao Xishan , Sun Hongtao , Vladau Costin , Franek Jacob A. , Feng Biao , Urquhart Bradley L. , Zhong Robert , Freeman David J. , Garcia Bertha , Min Wei-Ping
Published: April 2014

Tumor-derived immune suppression is a major impediment to successful immune/gene cancer therapy. In the present study, we describe a novel strategy to disrupt tumor-derived immune suppression by silencing a tolerogenic molecule of tumor origin, IDO, using small interfering RNA (siRNA). Silencing of IDO in B16F10 cells in vitro using IDO-siRNA prevented catabolism of tryptophan and inhibited apoptosis of T cells. IDO-siRNA treatment of B16F10 cells in vitro inhibited subsequent growth, tumor formation, and the size of tumor formed, by those cells when transplanted into host mice. In vivo treatment of B16F10 tumor-bearing mice successfully postponed tumor formation time and significantly decreased tumor size. Furthermore, in vivo IDO-siRNA treatment resulted in recovery of T cells responses and enhancement of tumor-specific killing. Thus, silencing IDO may break tumor-derived immune suppression. These data indicate that RNA interference has potential to enhance cancer therapy by reinstalling anticancer immunity.
Human CD4+ T Cells Lyse Target Cells via Granzyme/Perforin upon Circumvention of MHC Class II Restriction by an Antibody-Like Immunoreceptor
Authors: Hombach Andreas , Köhler Heike , Rappl Gunter , Abken Hinrich
Published: April 2014

Immune elimination of tumor cells requires the close cooperation between CD8+ CTL and CD4+ Th cells. We circumvent MHC class II-restriction of CD4+ T cells by expression of a recombinant immunoreceptor with an Ab-derived binding domain redirecting specificity. Human CD4+ T cells grafted with an immunoreceptor specific for carcinoembryonic Ag (CEA) are activated to proliferate and secrete cytokines upon binding to CEA+ target cells. Notably, redirected CD4+ T cells mediate cytolysis of CEA+ tumor cells with high efficiencies. Lysis by redirected CD4+ T cells is independent of death receptor signaling via TNF-α or Fas, but mediated by perforin and granzyme because cytolysis is inhibited by blocking the release of cytotoxic granules, but not by blocking of Fas ligand or TNF-α. CD4+ T cells redirected by Ab-derived immunoreceptors in a MHC class II-independent fashion substantially extend the power of an adoptive, Ag-triggered immunotherapy not only by CD4+ T cell help, but also by cytolytic effector functions. Because cytolysis is predominantly mediated via granzyme/perforin, target cells that are resistant to death receptor signaling become sensitive to a cytolytic attack by engineered CD4+ T cells.
Macrophage Migration Inhibitory Factor Deficiency Attenuates Macrophage Recruitment, Glomerulonephritis, and Lethality in MRL/lpr Mice
Authors: Hoi Alberta Y. , Hickey Michael J. , Hall Pamela , Yamana Jiro , O’Sullivan Kim M. , Santos Leilani L. , James Will G. , Kitching A. Richard , Morand Eric F.
Published: April 2014

Systemic lupus erythematosus (SLE) is a serious systemic autoimmune disease of unknown etiology. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is operative in innate and adaptive immunity and important in immune-mediated diseases such as rheumatoid arthritis and atherosclerosis. The functional relevance of MIF in systemic autoimmune diseases such as SLE is unknown. Using the lupus-prone MRL/lpr mice, we aim to examine the expression and function of MIF in this murine model of systemic autoimmune disease. These experiments revealed that renal MIF expression was significantly higher in MRL/lpr mice compared with nondiseased control mice (MRL/MpJ), and MIF was also markedly up-regulated in skin lesions of MRL/lpr mice. To examine the effect of MIF on development of systemic autoimmune disease, we generated MRL/lpr mice with a targeted disruption of the MIF gene (MIF−/−MRL/lpr), and compared their disease manifestations to MIF+/+MRL/lpr littermates. MIF−/−MRL/lpr mice exhibited significantly prolonged survival, and reduced renal and skin manifestations of SLE. These effects occurred in the absence of major changes in T and B cell markers or alterations in autoantibody production. In contrast, renal macrophage recruitment and glomerular injury were significantly reduced in MIF−/−MRL/lpr mice, and this was associated with reduction in the monocyte chemokine MCP-1. Taken together, these data suggest MIF as a critical effector of organ injury in SLE.
Amelioration of Mercury-Induced Autoimmunity by 4-1BB
Authors: Vinay Dass S. , Kim Jung D. , Kwon Byoung S.
Published: April 2014

In certain strains of mice, subtoxic doses of HgCl2 (mercuric chloride; mercury) induce a complex autoimmune condition characterized by the production of antinucleolar IgG Abs, lymphoproliferation, increased serum levels of IgG1/IgE Abs, and deposition of renal immune complexes. 4-1BB is an important T cell costimulatory molecule that has been implicated in T cell proliferation and cytokine production, especially production of IFN-γ. To elucidate T cell control mediated by the 4-1BB signaling pathway in this syndrome, we assessed the effect of administering agonistic anti-4-1BB mAb on mercury-induced autoimmunity. Groups of A.SW mice (H-2s) received mercury/control Ig or mercury/anti-4-1BB or PBS alone. Anti-4-1BB mAb treatment resulted in a dramatic reduction of mercury-induced antinucleolar Ab titers, serum IgG1/IgE induction, and renal Ig deposition. These effects may be related to the present finding that anti-4-1BB mAb decreases B cell numbers and function. The anti-4-1BB mAb-treated mercury group also showed a marked reduction in Th2-type cytokines but an increase in Th1-type cytokines and chemokines. Increased IFN-γ production due to anti-4-1BB mAb treatment appears to be responsible for the observed B cell defects because neutralization of IFN-γ in vivo substantially restored B cell numbers and partly restored IgG1/IgE. Collectively, our results indicate that 4-1BB mAb can down-regulate mercury-induced autoimmunity by affecting B cell function in an IFN-γ-dependent manner and thus, preventing the development of autoantibody production and tissue Ig deposition.
Reduced Frequency, Diversity, and Function of Human T Cell Leukemia Virus Type 1-Specific CD8+ T Cell in Adult T Cell Leukemia Patients
Authors: Kozako Tomohiro , Arima Naomichi , Toji Shingo , Masamoto Izumi , Akimoto Masaki , Hamada Heiichiro , Che Xiao-Fang , Fujiwara Hiroshi , Matsushita Kakushi , Tokunaga Masahito , Haraguchi Koichi , Uozumi Kimiharu , Suzuki Susumu , Takezaki Toshiro , Sonoda Shunro
Published: April 2014

Human T cell lymphotropic virus type 1 (HTLV-1)-specific CTL are thought to be immune effectors that reduce the risk of adult T cell leukemia (ATL). However, in vivo conditions of anti-HTLV-1 CTL before and after ATL development have yet to be determined. To characterize anti-HTLV-1 CTL in asymptomatic HTLV-1 carriers (AC) and ATL patients, we analyzed the frequency and diversity of HTLV-1-specific CD8+ T cells in PBMC of 35 AC and 32 ATL patients using 16 distinct epitopes of HTLV-1 Tax or Env/HLA tetramers along with intracellular cytolytic effector molecules (IFN-γ, perforin, and granzyme B). Overall frequency of subjects possessing Tax-specific CD8+ T cells was significantly lower in ATL than AC (53 vs 90%; p = 0.001), whereas the difference in Env-specific CD8+ T cells was not statistically significant. AC possessed Tax11–19/HLA-A*0201-specific tetramer+ cells by 90% and Tax301–309/HLA-A*2402-specific tetramer+ cells by 92%. Some AC recognized more than one epitope. In contrast, ATL recognized only Tax11–19 with HLA-A*0201 and Tax301–309 with HLA-A*2402 at frequencies of 30 and 55%. There were also significant differences in percentage of cells binding Tax11–19/HLA-A*0201 and Tax301–309/HLA-A*2402 tetramers between AC and ATL. Anti-HTLV-1 Tax CD8+ T cells in AC and ATL produced IFN-γ in response to Tax. In contrast, perforin and granzyme B expression in anti-HTLV-1 CD8+ T cells of ATL was significant lower than that of AC. Frequency of Tax-specific CD8+ T cells in AC was related to proviral load in HLA-A*0201. These results suggest that decreased frequency, diversity, and function of anti-HTLV-1 Tax CD8+ T cell clones may be one of the risks of ATL development.
Interaction of Vascular Endothelial Growth Factor 165 with Neuropilin-1 Protects Rheumatoid Synoviocytes from Apoptotic Death by Regulating Bcl-2 Expression and Bax Translocation
Authors: Kim Wan-Uk , Kang Soon Suk , Yoo Seung-Ah , Hong Kyung-Hee , Bae Dong-Goo , Lee Mi-Sook , Hong Seung Woo , Chae Chi-Bom , Cho Chul-Soo
Published: April 2014

Rheumatoid arthritis (RA) synoviocytes are resistant to apoptosis and exhibit a transformed phenotype, which might be caused by chronic exposure to genotoxic stimuli including reactive oxygen species and growth factors. In this study, we investigated the role of vascular endothelial growth factor165 (VEGF165), a potent angiogenic factor, and its receptor in the apoptosis of synoviocytes. We demonstrated here that neuropilin-1, rather than fms-like tyrosine kinase-1 and kinase insert domain-containing receptor, is the major VEGF165 receptor in the fibroblast-like synoviocytes. Neuropilin-1 was highly expressed in the lining layer, infiltrating leukocytes, and endothelial cells of rheumatoid synovium. The production of VEGF165, a ligand for neuropilin, was significantly higher in the RA synoviocytes than in the osteoarthritis synoviocytes. The ligation of recombinant VEGF165 to its receptor prevented the apoptosis of synoviocytes induced by serum starvation or sodium nitroprusside (SNP). VEGF165 rapidly triggered phospho-Akt and phospho-ERK activity and then induced Bcl-2 expression in the rheumatoid synoviocytes. The Akt or ERK inhibitor cancelled the protective effect of VEGF165 on SNP-induced synoviocyte apoptosis. Moreover, VEGF165 blocks SNP-induced Bcl-2 down-regulation as well as SNP-induced Bax translocation from the cytosol to the mitochondria. The down-regulation of the neuropilin-1 transcripts by short interfering RNA caused spontaneous synoviocyte apoptosis, which was associated with both the decrease in Bcl-2 expression and the increase in Bax translocation to mitochondria. Collectively, our data suggest that the interaction of VEGF165 with neuropilin-1 is crucial to the survival of rheumatoid synoviocytes and provide important implications for the abnormal growth of synoviocytes and therapeutic intervention in RA.
Innate Immune Responses to Human Malaria: Heterogeneous Cytokine Responses to Blood-Stage Plasmodium falciparum Correlate with Parasitological and Clinical Outcomes
Authors: Walther Michael , Woodruff John , Edele Fanny , Jeffries David , Tongren Jon E. , King Elizabeth , Andrews Laura , Bejon Philip , Gilbert Sarah C. , De Souza Joseph B. , Sinden Robert , Hill Adrian V. S. , Riley Eleanor M.
Published: April 2014

Taking advantage of a sporozoite challenge model established to evaluate the efficacy of new malaria vaccine candidates, we have explored the kinetics of systemic cytokine responses during the prepatent period of Plasmodium falciparum infection in 18 unvaccinated, previously malaria-naive subjects, using a highly sensitive, bead-based multiplex assay, and relate these data to peripheral parasite densities as measured by quantitative real-time PCR. These data are complemented with the analysis of cytokine production measured in vitro from whole blood or PBMC, stimulated with P. falciparum-infected RBC. We found considerable qualitative and quantitative interindividual variability in the innate responses, with subjects falling into three groups according to the strength of their inflammatory response. One group secreted moderate levels of IFN-γ and IL-10, but no detectable IL-12p70. A second group produced detectable levels of circulating IL-12p70 and developed very high levels of IFN-γ and IL-10. The third group failed to up-regulate any significant proinflammatory responses, but showed the highest levels of TGF-β. Proinflammatory responses were associated with more rapid control of parasite growth but only at the cost of developing clinical symptoms, suggesting that the initial innate response may have far-reaching consequences on disease outcome. Furthermore, the in vitro observations on cytokine kinetics presented here, suggest that intact schizont-stage infected RBC can trigger innate responses before rupture of the infected RBC.
Variability and Exclusion in Host and Parasite: Epigenetic Regulation of Ig and var Expression
Authors: Fraenkel Shira , Bergman Yehudit
Published: April 2014

The immune system generates highly diverse AgRs of different specificities from a pool of designated genomic loci, each containing large arrays of genes. Ultimately, each B or T cell expresses a receptor of a single type on its surface. Immune evasion by the malaria parasite Plasmodium falciparum is mediated by the mutually exclusive expression of a single member of the var family of genes, which encodes variant surface Ags. In this review, we discuss the similarities as well as the unique characteristics of the epigenetic mechanisms involved in the establishment of mutually exclusive expression in the immune and parasite systems.
Cutting Edge: Role of TANK-Binding Kinase 1 and Inducible IκB Kinase in IFN Responses against Viruses in Innate Immune Cells
Authors: Matsui Kosuke , Kumagai Yutaro , Kato Hiroki , Sato Shintaro , Kawagoe Tatsukata , Uematsu Satoshi , Takeuchi Osamu , Akira Shizuo
Published: April 2014

TANK-binding kinase 1 (TBK1) and inducible IκB kinase (IKK-i) are involved in the activation of transcription factors inducing the production of type I IFNs. Although TBK1, but not IKK-i, is critical for LPS-induced IFN induction, the role of these kinases in the responses against viral infection is yet to be determined. In this study, we show that type I IFN production against various RNA viruses was completely abrogated in conventional dendritic cells (DCs) and macrophages induced from fetal liver cells lacking both TBK1 and IKK-i, whereas considerable amounts of IFN were produced in cells lacking either of them. Microarray analysis revealed that various IFN-inducible genes were also regulated by the kinases. In contrast, Fms-like tyrosine kinase 3 ligand-induced DCs produced IFN-α even in the absence of both TBK1 and IKK-i. Thus, these two kinases are essential and compensate each other for the regulation of IFN responses in innate immune cells except plasmacytoid DCs.
Harboring of Particulate Allergens within Secretory Compartments by Mast Cells following IgE/FcεRI-Lipid Raft-Mediated Phagocytosis
Authors: Shin Jeoung-Sook , Shelburne Christopher P. , Jin Cong , LeFurgey E. Ann , Abraham Soman N.
Published: April 2014

Although much is known regarding the exocytic responses of mast cells following allergen/IgE-mediated activation, little is currently known of the fate of the activating allergens, many of which are particles. We have found that IgE-bound particulate allergens were phagocytosed by activated mast cells in a lipid raft-dependent manner. The nascent allergen-containing phagosomes were found to transform into granule compartments by acquiring VAMP7 and serotonin and exhibited the capacity to empty their contents upon mast cell activation. When allergen-harboring mast cells were stimulated, the intracellular allergens were expelled intact and shown to activate adjacent mast cells. This capacity of mast cells to phagocytose and retain whole and antigenically intact allergens could potentially contribute to the course of inflammatory diseases such as asthma.
Critical YxKxHxxxRP Motif in the C-Terminal Region of GATA3 for Its DNA Binding and Function
Authors: Shinnakasu Ryo , Yamashita Masakatsu , Shinoda Kenta , Endo Yusuke , Hosokawa Hiroyuki , Hasegawa Akihiro , Ikemizu Shinji , Nakayama Toshinori
Published: April 2014

A zinc finger transcription factor, GATA3, plays an essential role in the development of T cells and the functional differentiation into type 2 Th cells. Two transactivation domains and two zinc finger regions are known to be important for the GATA3 function, whereas the role for other regions remains unclear. In this study we demonstrated that a conserved YxKxHxxxRP motif (aa 345–354) adjacent to the C-terminal zinc finger domain of GATA3 plays a critical in its DNA binding and functions, including transcriptional activity, the ability to induce chromatin remodeling of the Th2 cytokine gene loci, and Th2 cell differentiation. A single point mutation of the key amino acid (Y, K, H, R, and P) in the motif abrogated GATA3 functions. A computer simulation analysis based on the solution structure of the chicken GATA1/DNA complex supported the importance of this motif in GATA3 DNA binding. Thus, we identified a novel conserved YxKxHxxxRP motif adjacent to the C-terminal zinc finger domain of GATA3 that is indispensable for GATA3 DNA binding and functions.
Aryl Hydrocarbon Receptor Activation Impairs the Priming but Not the Recall of Influenza Virus-Specific CD8+ T Cells in the Lung
Authors: Lawrence B. Paige , Roberts Alan D. , Neumiller Joshua J. , Cundiff Jennifer A. , Woodland David L.
Published: April 2014

The response of CD8+ T cells to influenza virus is very sensitive to modulation by aryl hydrocarbon receptor (AhR) agonists; however, the mechanism underlying AhR-mediated alterations in CD8+ T cell function remains unclear. Moreover, very little is known regarding how AhR activation affects anamnestic CD8+ T cell responses. In this study, we analyzed how AhR activation by the pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) alters the in vivo distribution and frequency of CD8+ T cells specific for three different influenza A virus epitopes during and after the resolution of a primary infection. We then determined the effects of TCDD on the expansion of virus-specific memory CD8+ T cells during recall challenge. Adoptive transfer of AhR-null CD8+ T cells into congenic AhR+/+ recipients, and the generation of CD45.2AhR−/−→CD45.1AhR+/+ chimeric mice demonstrate that AhR-regulated events within hemopoietic cells, but not directly within CD8+ T cells, underlie suppressed expansion of virus-specific CD8+ T cells during primary infection. Using a dual-adoptive transfer approach, we directly compared the responsiveness of virus-specific memory CD8+ T cells created in the presence or absence of TCDD, which revealed that despite profound suppression of the primary response to influenza virus, the recall response of virus-specific CD8+ T cells that form in the presence of TCDD is only mildly impaired. Thus, the delayed kinetics of the recall response in TCDD-treated mice reflects the fact that there are fewer memory cells at the time of reinfection rather than an inherent defect in the responsive capacity of virus-specific memory CD8+ cells.
Characterization of Foxp3+CD4+CD25+ and IL-10-Secreting CD4+CD25+ T Cells during Cure of Colitis
Authors: Uhlig Holm H. , Coombes Janine , Mottet Christian , Izcue Ana , Thompson Claire , Fanger Andrea , Tannapfel Andrea , Fontenot Jason D. , Ramsdell Fred , Powrie Fiona
Published: April 2014

CD4+CD25+ regulatory T cells can prevent and resolve intestinal inflammation in the murine T cell transfer model of colitis. Using Foxp3 as a marker of regulatory T cell activity, we now provide a comprehensive analysis of the in vivo distribution of Foxp3+CD4+CD25+ cells in wild-type mice, and during cure of experimental colitis. In both cases, Foxp3+CD4+CD25+ cells were found to accumulate in the colon and secondary lymphoid organs. Importantly, Foxp3+ cells were present at increased density in colon samples from patients with ulcerative colitis or Crohn’s disease, suggesting similarities in the behavior of murine and human regulatory cells under inflammatory conditions. Cure of murine colitis was dependent on the presence of IL-10, and IL-10-producing CD4+CD25+ T cells were enriched within the colon during cure of colitis and also under steady state conditions. Our data indicate that although CD4+CD25+ T cells expressing Foxp3 are present within both lymphoid organs and the colon, subsets of IL-10-producing CD4+CD25+ T cells are present mainly within the intestinal lamina propria suggesting compartmentalization of the regulatory T cell response at effector sites.
“Alternatively Activated” Dendritic Cells Preferentially Secrete IL-10, Expand Foxp3+CD4+ T Cells, and Induce Long-Term Organ Allograft Survival in Combination with CTLA4-Ig
Authors: Lan Yuk Yuen , Wang Zhiliang , Raimondi Giorgio , Wu Wenhan , Colvin Bridget L. , De Creus An , Thomson Angus W.
Published: April 2014

In this study, we propagated myeloid dendritic cells (DC) from BALB/c (H2d) mouse bone marrow progenitors in IL-10 and TGF-β, then stimulated the cells with LPS. These “alternatively activated” (AA) DC expressed lower TLR4 transcripts than LPS-stimulated control DC and were resistant to maturation. They expressed comparatively low levels of surface MHC class II, CD40, CD80, CD86, and programmed death-ligand 2 (B7-DC; CD273), whereas programmed death-ligand 1 (B7-H1; CD274) and inducible costimulatory ligand expression were unaffected. AADC secreted much higher levels of IL-10, but lower levels of IL-12p70 compared with activated control DC. Their poor allogeneic (C57BL/10; B10) T cell stimulatory activity and ability to induce alloantigen-specific, hyporesponsive T cell proliferation was not associated with enhanced T cell apoptosis. Increased IL-10 production was induced in the alloreactive T cell population, wherein CD4+Foxp3+ cells were expanded. The AADC-expanded allogeneic CD4+CD25+ T cells showed enhanced suppressive activity for T cell proliferative responses compared with freshly isolated T regulatory cells. In vivo migration of AADC to secondary lymphoid tissue was not impaired. A single infusion of BALB/c AADC to quiescent B10 recipients induced alloantigen-specific hyporesponsive T cell proliferation and prolonged subsequent heart graft survival. This effect was potentiated markedly by CTLA4-Ig, administered 1 day after the AADC. Transfer of CD4+ T cells from recipients of long-surviving grafts (>100 days) that were infiltrated with CD4+Foxp3+ cells, prolonged the survival of donor-strain hearts in naive recipients. These data enhance insight into the regulatory properties of AADC and demonstrate their therapeutic potential in vascularized organ transplantation.
Resolvin D Series and Protectin D1 Mitigate Acute Kidney Injury
Authors: Duffield Jeremy S. , Hong Song , Vaidya Vishal S. , Lu Yan , Fredman Gabrielle , Serhan Charles N. , Bonventre Joseph V.
Published: April 2014

Omega-3 fatty acid docosahexaenoic acid is converted to potent resolvins (Rv) and protectin D1 (PD1), two newly identified families of natural mediators of resolution of inflammation. We report that, in response to bilateral ischemia/reperfusion injury, mouse kidneys produce D series resolvins (RvDs) and PD1. Administration of RvDs or PD1 to mice before the ischemia resulted in a reduction in functional and morphological kidney injury. Initiation of RvDs and RvD1 administration 10 min after reperfusion also resulted in protection of the kidney as measured by serum creatinine 24 and 48 h later. Interstitial fibrosis after ischemia/reperfusion was reduced in mice treated with RvDs. Both RvDs and PD1 reduced the number of infiltrating leukocytes and blocked TLR-mediated activation of macrophages. Thus, the renal production of Rv and protectins, a previously unrecognized endogenous anti-inflammatory response, may play an important role in protection against and resolution of acute kidney injury. These data may also have therapeutic implications for potentiation of recovery from acute kidney injury.
B7-H1-Induced Apoptosis as a Mechanism of Immune Privilege of Corneal Allografts
Authors: Hori Junko , Wang Mingcong , Miyashita Megumi , Tanemoto Keiko , Takahashi Hiroshi , Takemori Toshitada , Okumura Ko , Yagita Hideo , Azuma Miyuki
Published: April 2014

The programmed death-1 (PD-1) costimulatory pathway has been demonstrated to play a role in the regulation of immune responses and peripheral tolerance. We investigated the role of this pathway in establishing an immune privilege status of corneal allografts in mice. B7-H1, but not B7-DC or PD-1, was expressed constitutively in the eye, i.e., cornea, iris-ciliary body, and retina. After corneal allografting, PD-1+CD4+ T cells infiltrated and adhered with B7-H1+ corneal endothelium. Blockade of PD-1 or B7-H1, but not B7-DC, led to accelerated corneal allograft rejection. In B7-H1-expressing corneal allografts, apoptosis of the infiltrating PD-1+CD4+ or CD8+ T cells was observed, after which there was allograft acceptance. In contrast, B7-H1 blockade suppressed apoptosis of infiltrating PD-1+ T cells, which led to allograft rejection. In vitro, destruction of corneal endothelial cells by alloreactive T cells was enhanced when the cornea was pretreated with anti-B7-H1 Ab. This is the first demonstration that the constitutive expression of B7-H1 plays a critical role in corneal allograft survival. B7-H1 expressed on corneal endothelial cells maintains long-term acceptance of the corneal allografts by inducing apoptosis of effector T cells within the cornea.
Enhanced Immunogenicity of Heat Shock Protein 70 Peptide Complexes from Dendritic Cell-Tumor Fusion Cells
Authors: Enomoto Yutaka , Bharti Ajit , Khaleque Ad Abdul , Song Baizheng , Liu Chunlei , Apostolopoulos Vasso , Xing Pei-xiang , Calderwood Stuart K. , Gong Jianlin
Published: April 2014

We have developed a molecular chaperone-based tumor vaccine that reverses the immune tolerance of cancer cells. Heat shock protein (HSP) 70 extracted from fusions of dendritic (DC) and tumor cells (HSP70.PC-F) possess superior properties such as stimulation of DC maturation and T cell proliferation over its counterpart from tumor cells. More importantly, immunization of mice with HSP70.PC-F resulted in a T cell-mediated immune response including significant increase of CD8 T cells and induction of the effector and memory T cells that was able to break T cell unresponsiveness to a nonmutated tumor Ag and provide protection of mice against challenge with tumor cells. By contrast, the immune response to vaccination with HSP70-PC derived from tumor cells is muted against such nonmutated tumor Ag. HSP70.PC-F complexes differed from those derived from tumor cells in a number of key manners, most notably, enhanced association with immunologic peptides. In addition, the molecular chaperone HSP90 was found to be associated with HSP70.PC-F as indicated by coimmunoprecipitation, suggesting ability to carry an increased repertoire of antigenic peptides by the two chaperones. Significantly, activation of DC by HSP70.PC-F was dependent on the presence of an intact MyD88 gene, suggesting a role for TLR signaling in DC activation and T cell stimulation. These experiments indicate that HSP70-peptide complexes (PC) derived from DC-tumor fusion cells have increased their immunogenicity and therefore constitute an improved formulation of chaperone protein-based tumor vaccine.
CD4 T Cell-Induced, Bid-Dependent Apoptosis of Cutaneous Dendritic Cells Regulates T Cell Expansion and Immune Responses
Authors: Pradhan Sanjay , Genebriera Joseph , Denning Warren L. , Felix Kumar , Elmets Craig A. , Timares Laura
Published: April 2014

The fate of dendritic cells (DCs) after Ag presentation may be DC subset-specific and controlled by many factors. The role of activation-induced apoptosis in regulating DC function is not clear. We investigated the fate of cutaneous DCs (cDCs), specifically Langerhans cells (LCs), and observed that they undergo apoptosis after successful Ag presentation to CD4 T cells. Caspase-specific inhibitors revealed that LC lines use a type II apoptosis pathway in response to CD4 T cells. In support of this, BH3-interacting domain (Bid) protein was present at high levels and specifically cleaved in the presence of Ag-specific T cells. Significant resistance to apoptosis by OT-2 CD4 cells was also observed for Bid knockout (KO) LCs in vitro. To test whether Bid was required to regulate LC function in vivo, we measured contact sensitization and topical immunization responses in Bid KO mice and observed markedly enhanced ear swelling and proliferation responses compared with wild-type mice. Furthermore, when Ag-pulsed Bid KO migratory cDCs were inoculated into wild-type recipients, an increase in both the rate and percentage of expanded OT-2 T cells expressing IFN-γ was observed. Thus, enhanced Ag presentation function was intrinsic to Bid KO cDCs. Therefore, Bid is an important regulator of LC viability and Ag presentation function.
Subepithelial Myofibroblasts are Novel Nonprofessional APCs in the Human Colonic Mucosa
Authors: Saada Jamal I. , Pinchuk Irina V. , Barrera Carlos A. , Adegboyega Patrick A. , Suarez Giovanni , Mifflin Randy C. , Di Mari John F. , Reyes Victor E. , Powell Don W.
Published: April 2014

The human gastrointestinal mucosa is exposed to a diverse normal microflora and dietary Ags and is a common site of entry for pathogens. The mucosal immune system must respond to these diverse signals with either the initiation of immunity or tolerance. APCs are important accessory cells that modulate T cell responses which initiate and maintain adaptive immunity. The ability of APCs to communicate with CD4+ T cells is largely dependent on the expression of class II MHC molecules by the APCs. Using immunohistochemistry, confocal microscopy, and flow cytometry, we demonstrate that α-smooth muscle actin+, CD90+ subepithelial myofibroblasts (stromal cells) constitutively express class II MHC molecules in normal colonic mucosa and that they are distinct from professional APCs such as macrophages and dendritic cells. Primary isolates of human colonic myofibroblasts (CMFs) cultured in vitro were able to stimulate allogeneic CD4+ T cell proliferation. This process was dependent on class II MHC and CD80/86 costimulatory molecule expression by the myofibroblasts. We also demonstrate that CMFs, engineered to express a specific DR4 allele, can process and present human serum albumin to a human serum albumin-specific and DR4 allele-restricted T cell hybridoma. These studies characterize a novel cell phenotype which, due to its strategic location and class II MHC expression, may be involved in capture of Ags that cross the epithelial barrier and present them to lamina propria CD4+ T cells. Thus, human CMFs may be important in regulating local immunity in the colon.