bluuebunny/crossref_metadata_2025 huggingface dataset:
IL-6 Produced by Dendritic Cells from Lupus-Prone Mice Inhibits CD4+CD25+ T Cell Regulatory Functions
Authors: Wan Suigui , Xia Changqing , Morel Laurence
Published: April 2014

The B6.Sle1.Sle2.Sle3 triple congenic mouse (B6.TC) is a model of lupus coexpressing the three major NZM2410-derived susceptibility loci on a C57BL/6 background. B6.TC mice produce high titers of antinuclear nephrogenic autoantibodies and a highly penetrant glomerulonephritis. Previous studies have shown the Sle1 locus is associated with a reduced number of regulatory T cells (Treg) and that Sle3 results in intrinsic defects of myeloid cells that hyperactivate T cells. In this report, we show that B6.TC dendritic cells (DCs) accumulate in lymphoid organs and present a defective maturation process, in which bone marrow-derived, plasmacytoid, and myeloid DCs express a significantly lower level of CD80, CD86, and MHC class II. B6.TC DCs also induce a higher level of proliferation in CD4+ T cells than B6 DCs, and B6.TC DCs block the suppressive activity of Treg. B6.TC DCs overproduce IL-6, which is necessary for the blockade of Treg activity, as shown by the effect of anti-IL-6 neutralizing Ab in the suppression assays. The overproduction of IL-6 by DCs and the blockade of Treg activity maps to Sle1, which therefore not only confers a reduced number of Treg but also blocks their ability to regulate autoreactive T cells. Taken together, these results provide a genetic and mechanistic evidence for systemic autoimmunity resulting from an impaired regulatory T cell compartment in both number and function and for Sle1-expressing DCs playing a major role in the latter defect though their production of IL-6.
IL-2 Receptor β-Dependent STAT5 Activation Is Required for the Development of Foxp3+ Regulatory T Cells
Authors: Burchill Matthew A. , Yang Jianying , Vogtenhuber Christine , Blazar Bruce R. , Farrar Michael A.
Published: April 2014

IL-2 −/− mice develop autoimmunity despite having relatively normal numbers of regulatory T cells (Tregs). In contrast, we demonstrate that IL-2−/− × IL-15−/− and IL-2Rβ−/− mice have a significant decrease in Treg numbers. Ectopic expression of foxp3 in a subset of CD4+ T cells rescued Treg development and prevented autoimmunity in IL-2Rβ−/− mice, suggesting that IL-2Rβ-dependent signals regulate foxp3 expression in Tregs. Subsequent analysis of IL-2Rβ-dependent signal transduction pathways established that the transcription factor STAT5 is necessary and sufficient for Treg development. Specifically, T cell-specific deletion of STAT5 prevented Treg development; conversely, reconstitution of IL-2Rβ−/− mice with bone marrow cells expressing an IL-2Rβ mutant that exclusively activates STAT5 restored Treg development. Finally, STAT5 binds to the promoter of the foxp3 gene suggesting that IL-2Rβ-dependent STAT5 activation promotes Treg differentiation by regulating expression of foxp3.
CD25+CD4+ Regulatory T Cell Migration Requires L-Selectin Expression: L-Selectin Transcriptional Regulation Balances Constitutive Receptor Turnover
Authors: Venturi Guglielmo M. , Conway Rochelle M. , Steeber Douglas A. , Tedder Thomas F.
Published: April 2014

The molecular mechanisms controlling regulatory CD25+Foxp3+CD4+ T cell (Treg) migration are central to in vivo immune responses. Treg cell subsets differentially express L-selectin, an adhesion molecule mediating lymphocyte migration to peripheral LNs (PLNs) and leukocyte rolling during inflammation. In this study, L-selectin was essential for Treg cell migration and normal tissue distribution. Specifically, there was a 90% reduction in PLN Treg cells in L-selectin−/− mice with a compensatory increase in spleen Treg cell numbers. Unexpectedly, however, 40% of the CD4+ T cells remaining within PLNs of L-selectin−/− mice were Treg cells. The migratory properties of Treg cells were nonetheless markedly different from those of naive CD4+ T cells, with 3- to 9-fold lower migration of Treg cells into PLNs and ∼2-fold lower migration into the spleen. Treg cells also turned over cell surface L-selectin at a faster rate than CD25−CD4+ T cells, but maintained physiologically appropriate L-selectin densities for optimal migration. Specifically, Treg cells expressed 30–40% more cell surface L-selectin when its endoproteolytic cleavage was blocked genetically, which resulted in a 2-fold increase in Treg cell migration into PLNs. However, increased L-selectin cleavage by Treg cells in wild-type mice was accompanied by 2-fold higher L-selectin mRNA levels, which resulted in equivalent cell surface L-selectin densities on Treg and naive T cells. Thus, Treg cells and CD25−CD4+ T cells share similar requirements for L-selectin expression during migration, although additional molecular mechanisms constrain Treg cell migration beyond what is required for naive CD4+ T cell migration.
Mycobacterium leprae Inhibits Dendritic Cell Activation and Maturation
Authors: Murray Rose Ann , Siddiqui Mahveen Ruby , Mendillo Megan , Krahenbuhl James , Kaplan Gilla
Published: April 2014

Leprosy presents with a clinical spectrum of skin lesions that span from strong Th1-mediated cellular immunity and control of bacillary growth at one pole to poor Ag-specific T cell immunity with extensive bacillary load and Th2 cytokine-expressing lesions at the other. To understand how the immune response to Mycobacterium leprae is regulated, human dendritic cells (DC), potent inducers of adaptive immune responses, exposed to M. leprae, Mycobacterium tuberculosis (Mtb), and Mycobacterium bovis bacillus Calmette-Guerin (BCG) were studied for their ability to be activated and to prime T cell proliferation. In contrast with Mtb and BCG, M. leprae did not induce DC activation/maturation as measured by the expression of selected surface markers and proinflammatory cytokine production. In MLR, T cells did not proliferate in response to M. leprae-stimulated DC. Interestingly, M. leprae-exposed MLR cells secreted increased Th2 cytokines as well as similar Th1 cytokine levels as compared with Mtb- and BCG-exposed cells. Gene expression analysis revealed a reduction in levels of mRNA of DC activation and maturation markers following exposure to M. leprae. Our data suggest that M. leprae does not induce and probably suppresses in vitro DC maturation/activation, whereas Mtb and BCG are stimulatory.
Essential Role of GATA Transcriptional Factors in the Activation of Mast Cells
Authors: Masuda Akio , Hashimoto Katsunori , Yokoi Toyoharu , Doi Takeshi , Kodama Tatsuhiko , Kume Hiroaki , Ohno Kinji , Matsuguchi Tetsuya
Published: April 2014

Mast cells are pivotal effector cells in IgE-mediated allergic reactions. GATA transcriptional factors such as GATA-1 and GATA-2 are expressed in mast cells, and recent studies have revealed that both GATA-1 and GATA-2 are required for mast cell development. However, the role of GATA transcriptional factors in differentiated mast cells has remained largely unknown. In this study, we repressed the activity of GATA-1 and GATA-2 by using three different approaches (inducible overexpression of a dominant-negative form of GATA, pharmacological inactivation, or small interfering RNA technology), and analyzed the molecular mechanisms of GATA transcriptional factors in the activation of mast cells. Surprisingly, the repression of GATA activity in differentiated mast cells led to the impairment of cell survival, IgE-induced degranulation, and cytokine production. Signal transduction and histone modification in the chromatin related to protein kinase Cβ were defective in these cells. These results identify that GATA has a critical role in the activation of mast cell.
GM-CSF Production by Autoreactive T Cells Is Required for the Activation of Microglial Cells and the Onset of Experimental Autoimmune Encephalomyelitis
Authors: Ponomarev Eugene D. , Shriver Leah P. , Maresz Katarzyna , Pedras-Vasconcelos Joao , Verthelyi Daniela , Dittel Bonnie N.
Published: April 2014

Multiple sclerosis (MS) is a CNS autoimmune disease believed to be triggered by T cells secreting Th1-specific proinflammatory cytokines, such as GM-CSF. In the animal model of MS, experimental autoimmune encephalomyelitis (EAE), Th1 but not Th2 cells have been shown to induce disease; however, to date, no single encephalitogenic T cell-derived cytokine has been shown to be required for EAE onset. Because GM-CSF-deficient mice have been shown to be resistant to EAE following immunization with myelin self-Ag, we investigated the cellular source of the required GM-CSF and found that GM-CSF production by encephalitogenic T cells, but not CNS resident or other peripheral cells, was required for EAE induction. Furthermore, we showed that microglial cell activation, but not peripheral macrophage activation, was a GM-CSF-dependent process. Activation of microglial cells by the injection of LPS abrogated the GM-CSF requirement for EAE induction, suggesting that microglial cell activation is required for EAE onset. These data also demonstrate that GM-CSF is a critical Th1 cell-derived cytokine required for the initiation of CNS inflammation associated with EAE, and likely MS.
IL-22 Participates in an Innate Anti-HIV-1 Host-Resistance Network through Acute-Phase Protein Induction
Authors: Missé Dorothée , Yssel Hans , Trabattoni Daria , Oblet Christelle , Lo Caputo Sergio , Mazzotta Francesco , Pène Jérome , Gonzalez Jean-Paul , Clerici Mario , Veas Francisco
Published: April 2014

Certain individuals are resistant to HIV-1 infection, despite repeated exposure to the virus. Although protection against HIV-1 infection in a small proportion of Caucasian individuals is associated with mutant alleles of the CCR5 HIV-1 coreceptor, the molecular mechanism underlying resistance in repeatedly HIV-1-exposed, uninfected individuals (EU) is unclear. In this study, we performed complementary transcriptome and proteome analyses on peripheral blood T cells, and plasma or serum from EU, their HIV-1-infected sexual partners, and healthy controls, all expressing wild-type CCR5. We report that activated T cells from EU overproduce several proteins involved in the innate immunity response, principally those including high levels of peroxiredoxin II, a NK-enhancing factor possessing strong anti-HIV activity, and IL-22, a cytokine involved in the production of acute-phase proteins such as the acute-phase serum amyloid A (A-SAA). Cell supernatants and serum levels of these proteins were up-regulated in EU. Moreover, a specific biomarker for EU detected in plasma was identified as an 8.6-kDa A-SAA cleavage product. Incubation of in vitro-generated myeloid immature dendritic cells with A-SAA resulted in CCR5 phosphorylation, down-regulation of CCR5 expression, and strongly decreased susceptibility of these cells to in vitro infection with a primary HIV-1 isolate. Taken together, these results suggest new correlates of EU protection and identify a cascade involving IL-22 and the acute phase protein pathway that is associated with innate host resistance to HIV infection.
Dysregulation of Src Family Kinases in Mast Cells from Epilepsy-Resistant ASK versus Epilepsy-Prone EL Mice
Authors: Kitaura Jiro , Kawakami Yuko , Maeda-Yamamoto Mari , Horejsi Vaclav , Kawakami Toshiaki
Published: April 2014

EL mice have been used as a model of epilepsy, whereas ASK mice are an epilepsy-resistant variant originating from a colony of EL mice. Mast cell-dependent anaphylaxis is easily inducible by stimulation with IgE and Ag in ASK mice, whereas EL mice are resistant to such stimuli. In this study we have characterized mast cells derived from these two strains. ASK mast cells proliferated more vigorously than EL cells in response to IL-3 and stem cell factor. Although ASK mast cells degranulated less vigorously than EL mast cells upon stimulation with IgE and Ag, ASK cells produced and secreted several-fold more TNF-α and IL-2 than EL cells. Consistent with the similarities of these ASK and EL mast cell responses with phenotypes of lyn−/− and wild-type mast cells, respectively, Lyn activity was reduced in ASK cells. In addition to the impaired Lyn activity, ASK cells just like lyn−/− cells exhibited reduced Syk activity, prolonged activation of ERK and JNK, and enhanced activation of Akt. Furthermore, the lipid raft-resident transmembrane adaptor protein Cbp/PAG that associates with Lyn was hypophosphorylated in ASK cells. Importantly, similar to lyn−/− cells, Fyn was hyperactivated in ASK cells. Therefore, these results are consistent with the notion that Lyn-dependent phosphorylation of Cbp/PAG negatively regulates Src family kinases. This study also suggests that reduced activity of Lyn, a negative regulator of mast cell activation, underlies the susceptibility of ASK mice to anaphylaxis and implies that dysregulation of Lyn and other Src family kinases contributes to epileptogenesis.
Dendritic Cell Transmigration through Brain Microvessel Endothelium Is Regulated by MIP-1α Chemokine and Matrix Metalloproteinases
Authors: Zozulya Alla L. , Reinke Emily , Baiu Dana C. , Karman Jozsef , Sandor Matyas , Fabry Zsuzsanna
Published: April 2014

Dendritic cells (DCs) accumulate in the CNS during inflammatory diseases, but the exact mechanism regulating their traffic into the CNS remains to be defined. We now report that MIP-1α increases the transmigration of bone marrow-derived, GFP-labeled DCs across brain microvessel endothelial cell monolayers. Furthermore, occludin, an important element of endothelial tight junctions, is reorganized when DCs migrate across brain capillary endothelial cell monolayers without causing significant changes in the barrier integrity as measured by transendothelial electrical resistance. We show that DCs produce matrix metalloproteinases (MMP) -2 and -9 and GM6001, an MMP inhibitor, decreases both baseline and MIP-1α-induced DC transmigration. These observations suggest that DC transmigration across brain endothelial cell monolayers is partly MMP dependent. The migrated DCs express higher levels of CD40, CD80, and CD86 costimulatory molecules and induce T cell proliferation, indicating that the transmigration of DCs across brain endothelial cell monolayers contributes to the maintenance of DC Ag-presenting function. The MMP dependence of DC migration across brain endothelial cell monolayers raises the possibility that MMP blockers may decrease the initiation of T cell recruitment and neuroinflammation in the CNS.
Urinary Bladder Epithelium Antigen Induces CD8+ T Cell Tolerance, Activation, and Autoimmune Response
Authors: Liu Wujiang , Evanoff David P. , Chen Xiaohong , Luo Yi
Published: April 2014

The effort to explore the specific autoimmune mechanisms of urinary bladder has long been hindered due to a lack of proper animal models. To better elucidate this issue, we developed a novel line of transgenic (Tg) mice, designated as URO-OVA mice, that express the model Ag OVA as a “self”-Ag on the bladder epithelium. URO-OVA mice are naturally tolerant to OVA and show no response to OVA stimulation. Adoptive transfer of naive OVA-specific T cells showed cell proliferation, activation, and infiltration but no bladder histopathology. In contrast, adoptive transfer of activated OVA-specific T cells induced OVA-mediated histological bladder inflammation. Increased mast cells and up-regulated mRNA expressions of TNF-α, nerve growth factor, and substance P precursor were also observed in the inflamed bladder. To further facilitate bladder autoimmunity study, we crossbred URO-OVA mice with OVA-specific CD8+ TCR Tg mice (OT-I mice) to generate a dual Tg line URO-OVA/OT-I mice. The latter mice naturally acquire clonal deletion for autoreactive OT-I CD8+ T cells (partial deletion in the thymus and severe deletion in the periphery). Despite this clonal deletion, URO-OVA/OT-I mice spontaneously develop autoimmune cystitis at 10 wk of age. Further studies demonstrated that the inflamed bladder contained infiltrating OT-I CD8+ T cells that had escaped clonal deletion and gained effector functions before developing histological bladder inflammation. Taken together, we demonstrate for the first time that the bladder epithelium actively presents self-Ag to the immune system and induces CD8+ T cell tolerance, activation, and autoimmune response.
A Local Antigen-Driven Humoral Response Is Present in the Inflammatory Myopathies
Authors: Bradshaw Elizabeth M. , Orihuela Ana , McArdel Shannon L. , Salajegheh Mohammad , Amato Anthony A. , Hafler David A. , Greenberg Steven A. , O’Connor Kevin C.
Published: April 2014

The inflammatory myopathies are putative autoimmune disorders characterized by muscle weakness and the presence of intramuscular inflammatory infiltrates. Although inclusion body myositis and polymyositis have been characterized as cytotoxic CD8+ T cell-mediated diseases, we recently demonstrated high frequencies of CD138+ plasma cells in the inflamed muscle tissue of patients with these diseases. To gain a deeper understanding of the role these B cell family members play in the disease pathology, we examined the molecular characteristics of the H chain portion of the Ag receptor. Biopsies of muscle tissue were sectioned and tissue regions and individual cells were isolated through laser capture microdissection. Ig H chain gene transcripts isolated from the sections, regions, and cells were used to determine the variable region gene sequences. Analysis of these sequences revealed clear evidence of affinity maturation in that significant somatic mutation, isotype switching, receptor revision, codon insertion/deletion, and oligoclonal expansion had occurred within the B and plasma cell populations. Moreover, analysis of tissue regions isolated by laser capture microdissection revealed both clonal expansion and variation, suggesting that local B cell maturation occurs within muscle. In contrast, sequences from control muscle tissues and peripheral blood revealed none of these characteristics found in inflammatory myopathy muscle tissue. Collectively, these data demonstrate that Ag drives a B cell Ag-specific response in muscle in patients with dermatomyositis, inclusion body myositis, and polymyositis. These findings highlight the need for a revision of the current paradigm of exclusively T cell-mediated intramuscular Ag-specific autoimmunity in inclusion body myositis and polymyositis.
B Cell Clonal Expansion and Somatic Hypermutation of Ig Variable Heavy Chain Genes in the Synovial Membrane of Patients with Osteoarthritis
Authors: Da Reng-Rong , Qin Yufen , Baeten Dominique , Zhang Yiping
Published: April 2014

Inflammatory mediators have been explored as possible factors in the initiation and/or progression of osteoarthritis (OA). This study shows that synovial infiltration by B lymphocytes is present in almost half of the knee OA cases. The degree of B lymphocyte infiltration is associated with more pronounced synovial inflammation and with the presence of plasma cells and lymphoid follicles in more severe cases. To examine whether these B cells are merely bystanders or could be involved in the pathogenesis of OA, we analyzed the Ig H chain variable region (VH) genes of B cells recovered from the synovial membrane of five OA patients with marked B cell infiltration. Sequence analysis of CDR3 regions of rearranged VDJ genes revealed clonal or oligoclonal B cell expansions in all cases. Expanded B cell clones in four of five OA patients showed clustered somatic mutations, occurring mainly in the CDRs and with a high replacement-to-silent ratio (>2.9), indicating that these cells are postgerminal center B cells that had been positively selected through their Ag receptor. These data demonstrate the presence in inflamed knee OA synovium of clonally expanded, Ag-driven B cells that may contribute to the development or progression of the disease.
Elicitation of T Cell Responses to Histologically Unrelated Tumors by Immunization with the Novel Cancer-Testis Antigen, Brother of the Regulator of Imprinted Sites
Authors: Ghochikyan Anahit , Mkrtichyan Mikayel , Loukinov Dmitri , Mamikonyan Gregory , Pack Svetlana D. , Movsesyan Nina , Ichim Thomas E. , Cribbs David H. , Lobanenkov Victor V. , Agadjanyan Michael G.
Published: April 2014

Brother of the regulator of imprinted sites (BORIS) was previously described as a transcription factor for epigenetic reprogramming the expression of which is strictly confined to germ cells of adult testes but is aberrantly activated in the vast majority of neoplastic cells. Considering the critical role of BORIS in cancerogenesis and the fact that its expression pattern may preclude thymic tolerance, we generated DNA- and protein-based mouse BORIS antitumor vaccines using a non-DNA-binding version of the BORIS molecule. Clinical use of BORIS as a vaccine Ag would require that certain safety concerns be met. Specifically, administration of the functional BORIS protein would hypothetically pose a risk of BORIS accelerating the progression of cancer. To alleviate such safety concerns, we have developed vaccines based on the BORIS molecule lacking the DNA-binding zinc fingers domain. To enhance anti-BORIS cellular immune responses, we used a standard molecular adjuvant approach. It consisted of plasmids encoding murine IL-12 and IL-18 for a DNA-based vaccine and conventional Th1 type adjuvant, Quil A, for a protein-based vaccine. Both DNA- and protein-based vaccines induced Ag-specific CD4+ T cell proliferation with Th1 and Th2 cytokine profiles, respectively. Protein-based, but not DNA-based, BORIS vaccine induced a significant level of Ab production in immunized animals. Importantly, potent anticancer CD8+-cytotoxic lymphocytes were generated after immunization with the DNA-based, but not protein-based, BORIS vaccine. These cytolytic responses were observed across a wide range of different mouse cancers including mammary adenocarcinoma, glioma, leukemia, and mastocytoma.
Suppression of Skin Lesions by Transdermal Application of CpG-Oligodeoxynucleotides in NC/Nga Mice, a Model of Human Atopic Dermatitis
Authors: Inoue Joe , Aramaki Yukihiko
Published: April 2014

Atopic dermatitis (AD) is a pruritic inflammatory skin disease characterized by an elevation of the total IgE level in plasma, the infiltration of mast cells and eosinophils, and the expression of cytokines by Th2 cells. NC/Nga mice kept in conventional conditions are known to develop skin lesions resembling human AD. We examined in this study the alterations of immune response in NC/Nga mice kept in conventional conditions, following transdermal application of CpG-oligodeoxynucleotides (ODN), which plays a critical role in immunity via the augmentation of Th1-type and suppression of Th2-type responses. CpG-ODN remarkably changed the immune response from type Th2 to Th1 as determined from cytokine mRNA and Ab levels. The serum IgE level was decreased and the expression of IgG2a was up-regulated. The application of CpG-ODN to the skin also decreased inflammatory infiltration of mast cells, and suppression in the skin lesions was observed. Furthermore, the generation of regulatory T cells, which are considered immune suppressive T cells, was observed in the skin on treatment with CpG-ODN. These results suggested CpG-ODN is effective for immunotherapy in patients with AD, which is characterized by Th2-dominated inflammation.
Regulation of Memory Antibody Levels: The Role of Persisting Antigen versus Plasma Cell Life Span
Authors: Gatto Dominique , Martin Stephen W. , Bessa Juliana , Pellicioli Erica , Saudan Philippe , Hinton Heather J. , Bachmann Martin F.
Published: April 2014

Protective Ab levels can be maintained for years upon infection or vaccination. In this study, we studied the duration of Ab responses as a function of the life span of plasma cells and tested the role of persisting Ag in maintaining B cell memory. Our analysis of B cell responses induced in mice immunized with virus-like particles demonstrates the following: 1) Ab titers are long-lived, but decline continuously with a t1/2 of ∼80 days, which corresponds to the life span of plasma cells; 2) the germinal center (GC) reaction, which lasts for up to 100 days, is dependent on Ag associated with follicular dendritic cells; and 3) early GCs produce massive numbers of plasma and memory B cell precursors, whereas the late Ag-dependent GCs are dispensable for the maintenance of Ab levels and B cell memory.
Immune Regulation by Microvascular Endothelial Cells: Directing Innate and Adaptive Immunity, Coagulation, and Inflammation
Authors: Danese Silvio , Dejana Elisabetta , Fiocchi Claudio
Published: April 2014

An effective immune response depends not only on the proper activation, regulation, and function of immune cells, but also on their distribution and retention in diverse tissue microenvironments where they encounter a number of stimuli and other cell types. These activities are mediated by endothelial cells, which form specialized microcirculatory networks used by immune cells under both physiological and pathological circumstances. Endothelial cells represent a highly heterogeneous population of cells with the ability to interact with and modulate the function of immune cells. This review is focused on the role of microvascular endothelial cells in innate and adaptive immunity, inflammation, coagulation, angiogenesis, and the therapeutic implications of targeting endothelial cells in selected autoimmune and chronic inflammatory disorders.
Cutting Edge: IPSE/alpha-1, a Glycoprotein fromSchistosoma mansoniEggs, Induces IgE-Dependent, Antigen-Independent IL-4 Production by Murine Basophils In Vivo
Authors: Schramm Gabriele , Mohrs Katja , Wodrich Maren , Doenhoff Michael J. , Pearce Edward J. , Haas Helmut , Mohrs Markus
Published: April 2014

During infection with the helminth parasite Schistosoma mansoni, the deposition of eggs coincides with the onset of IL-4 production and Th2 development. Although IL-4 is known as a potent inducer of Th2 differentiation, the mechanism by which schistosome eggs induce IL-4 production is not clear. In this study, we demonstrate that the S. mansoni egg Ag (SmEA) induces IgE-dependent IL-4 production by basophils derived from Heligmosomoides polygyrus-infected or OVA/alum-immunized mice in the absence of pathogen-specific IgE. The effect is mediated by the secretory glycoprotein IPSE/alpha-1, because IPSE/alpha-1-depleted SmEA no longer induces cytokine production. Conversely, recombinant IPSE/alpha-1 is sufficient to induce IL-4 production. Importantly, the injection of SmEA or recombinant IPSE/alpha-1 into H. polygyrus-infected 4get/KN2 IL-4 reporter mice rapidly induces the dose-dependent IL-4 production by basophils in the liver, a major site of egg deposition. Thus, IPSE/alpha-1 induces basophils to produce IL-4 even in the absence of Ag-specific IgE.
Cutting Edge: Conventional Dendritic Cells Are the Critical APC Required for the Induction of Experimental Cerebral Malaria
Authors: deWalick Saskia , Amante Fiona H. , McSweeney Karli A. , Randall Louise M. , Stanley Amanda C. , Haque Ashraful , Kuns Rachel D. , MacDonald Kelli P. A. , Hill Geoff R. , Engwerda Christian R.
Published: April 2014

Cerebral malaria (CM) is a serious complication of Plasmodium falciparum infection, causing significant morbidity and mortality among young children and nonimmune adults in the developing world. Although previous work on experimental CM has identified T cells as key mediators of pathology, the APCs and subsets therein required to initiate immunopathology remain unknown. In this study, we show that conventional dendritic cells but not plasmacytoid dendritic cells are required for the induction of malaria parasite-specific CD4+ T cell responses and subsequent experimental CM. These data have important implications for the development of malaria vaccines and the therapeutic management of CM.
Cutting Edge: Cross-Presented Intracranial Antigen Primes CD8+ T Cells
Authors: Walter Lisa , Albert Matthew L.
Published: April 2014

The CNS is considered immune privileged due to the blood-brain barrier and the absence of conventional lymphatics. Nonetheless, T cell immune responses specific for CNS Ag have been documented. Where these events are initiated and what cellular mechanisms are involved remain unknown. In this study, we established an experimental mouse model to evaluate the requirements for priming CD8+ T cells following the cross-presentation of intracranial Ag. Surprisingly, we find that even with a damaged blood-brain barrier, Ag presentation occurs in regional lymph nodes and not within the CNS itself. Only once the responding cells have expanded can they traffic to the site of CNS injury. Cross-presentation of intracranial Ag is efficient and the subsequent priming of CD8+ T cells is dependent on CD4+ T cell help and CD40 signaling in host APCs. Our findings have important implications for the initiation of T cell immune responses toward CNS Ags.
Nasal Cholera Toxin Elicits IL-5 and IL-5 Receptor α-Chain Expressing B-1a B Cells for Innate Mucosal IgA Antibody Responses
Authors: Kataoka Kosuke , Fujihashi Keiko , Sekine Shinichi , Fukuiwa Tatsuya , Kobayashi Ryoki , Suzuki Hideaki , Nagata Hideki , Takatsu Kiyoshi , Shizukuishi Satoshi , McGhee Jerry R. , Fujihashi Kohtaro
Published: April 2014

In this study, we examine whether native cholera toxin (nCT) as a mucosal adjuvant can support trinitrophenyl (TNP)-LPS-specific mucosal immune responses. C57BL/6 mice were given nasal TNP-LPS in the presence or absence of nCT. Five days later, significantly higher levels of TNP-specific mucosal IgA Ab responses were induced in the nasal washes, saliva, and plasma of mice given nCT plus TNP-LPS than in those given TNP-LPS alone. High numbers of TNP-specific IgA Ab-forming cells were also detected in mucosal tissues such as the nasal passages (NPs), the submandibular glands (SMGs), and nasopharyngeal-associated lymphoreticular tissue of mice given nCT. Flow cytometric analysis showed that higher numbers of surface IgA+, CD5+ B cells (B-1a B cells) in SMGs and NPs of mice given nasal TNP-LPS plus nCT than in those given TNP-LPS alone. Furthermore, increased levels of IL-5R α-chain were expressed by B-1a B cells in SMGs and NPs of mice given nasal TNP-LPS plus nCT. Thus, CD4+ T cells from these mucosal effector lymphoid tissues produce high levels of IL-5 at both protein and mRNA levels. When mice were treated with anti-IL-5 mAb, significant reductions in TNP-specific mucosal IgA Ab responses were noted in external secretions. These findings show that nasal nCT as an adjuvant enhances mucosal immune responses to a T cell-independent Ag due to the cross-talk between IL-5Rα+ B-1a B cells and IL-5-producing CD4+ T cells in the mucosal effector lymphoid tissues.
Allosuppressive Donor CD4+CD25+ Regulatory T Cells Detach from the Graft and Circulate in Recipients after Liver Transplantation
Authors: Demirkiran Ahmet , Bosma Brenda M. , Kok Alice , Baan Carla C. , Metselaar Herold J. , IJzermans Jan N. M. , Tilanus Hugo W. , Kwekkeboom Jaap , van der Laan Luc J. W.
Published: April 2014

Organ transplantation (Tx) results in a transfer of donor leukocytes from the graft to the recipient, which can lead to chimerism and may promote tolerance. It remains unclear whether this tolerance involves donor-derived regulatory T cells (Tregs). In this study, we examined the presence and allosuppressive activity of CD4+CD25+Foxp3+ Tregs in perfusates of human liver grafts and monitored the cells presence in the circulation of recipients after liver Tx. Vascular perfusions of 22 liver grafts were performed with University of Wisconsin preservation and albumin solutions. Flow cytometric analysis revealed that perfusate T cells had high LFA-1 integrin expression and had a reversed CD4 to CD8 ratio compared with control blood of healthy individuals. These findings indicate that perfusate cells are of liver origin and not derived from residual donor blood. Further characterization of perfusate mononuclear cells showed an increased proportion of CD4+CD25+CTLA4+ T cells compared with healthy control blood. Increased percentages of Foxp3+ cells, which were negative for CD127, confirmed the enrichment of Tregs in perfusates. In MLR, CD4+CD25+ T cells from perfusates suppressed proliferation and IFN-γ production of donor and recipient T cells. In vivo within the first weeks after Tx, up to 5% of CD4+CD25+CTLA4+ T cells in recipient blood were derived from the donor liver. In conclusion, a substantial number of donor Tregs detach from the liver graft during perfusion and continue to migrate into the recipient after Tx. These donor Tregs suppress the direct pathway alloresponses and may in vivo contribute to chimerism-associated tolerance early after liver Tx.
Unrestrained Glycogen Synthase Kinase-3β Activity Leads to Activated T Cell Death and Can Be Inhibited by Natural Adjuvant
Authors: Sengupta Sadhak , Jayaraman Padmini , Chilton Paula M. , Casella Carolyn R. , Mitchell Thomas C.
Published: April 2014

Activated T cell death (ATCD) after peak clonal expansion is required for effective homeostasis of the immune system. Using a mouse model of T cell clonal expansion and contraction, we found that regulation of the proapoptotic kinase glycogen synthase kinase (GSK)-3β plays a decisive role in determining the extent to which T cells are eliminated after activation. Involvement of GSK-3β in ATCD was tested by measuring T cell survival after GSK-3β inhibition, either ex vivo with chemical and pharmacological inhibitors or in vivo by retroviral expression of a dominant-negative form of GSK-3. We also measured amounts of inactivating phosphorylation of GSK-3β (Ser9) in T cells primed in the presence or absence of LPS. Our results show that GSK-3β activity is required for ATCD and that its inhibition promoted T cell survival. Adjuvant treatment in vivo maintained GSK-3β (Ser9) phosphorylation in activated T cells, whereas with adjuvant-free stimulation it peaked and then decayed as the cells became susceptible to ATCD. We conclude that the duration of GSK-3β inactivation determines activated T cell survival and that natural adjuvant stimulation decreases the severity of clonal contraction in part by keeping a critical proapoptotic regulatory factor, GSK-3β, inactivated.
Involvement of Heat Shock Protein (Hsp)90β but Not Hsp90α in Antiapoptotic Effect of CpG-B Oligodeoxynucleotide
Authors: Kuo Cheng-Chin , Liang Chi-Ming , Lai Chen-Yen , Liang Shu-Mei
Published: April 2014

Unmethylated CpG oligodeoxynucleotides (CpG ODNs) activate immune responses in a TLR9-dependent manner. In this study, we found that stimulation of mouse macrophages and dendritic cells with B-type CpG ODN (CpG-B ODN) increased the cellular level of heat shock protein (Hsp) 90β but not Hsp90α and prevented apoptosis induced by serum starvation or staurosporine treatment. The CpG-B ODN-induced Hsp90β expression depended on TLR9, MyD88, and PI3K. Inhibition of Hsp90β level by expressing small-interfering RNA suppressed not only Hsp90β expression but also PI3K-dependent phosphorylation of Akt and CpG-B ODN-mediated antiapoptosis. Additional studies demonstrated that as described by other group in mast cells, Hsp90β but not Hsp90α was associated with Bcl-2. Inhibition of Hsp90β suppressed the CpG-B ODN-induced association of Hsp90β with Bcl-2 and impaired the inhibitory effect of CpG-B ODN in the release of cytochrome c and activation of caspase-3. This study thus reveals the involvement of Hsp90β but not Hsp90α in CpG-B ODN-mediated antiapoptotic response and that Hsp90β is distinct from Hsp90α in regulation of the cellular function of immune cells.
TCRβ Chain That Forms Peptide-Independent Alloreactive TCR Transfers Reduced Reactivity with Irrelevant Peptide/MHC Complex
Authors: Santori Fabio R. , Popmihajlov Zoran , Badovinac Vladimir P. , Smith Courtney , Radoja Sasa , Harty John T. , Vukmanović Stanislav
Published: April 2014

A major feature of the TCR repertoire is strong alloreactivity. Peptides presented by allogeneic MHC are irrelevant for recognition by a subset of alloreactive T cells. To characterize peptide-independent TCRs at the molecular level, we forced the expression of a TCRβ chain isolated from a peptide-independent alloreactive CD8+ T cell line. The alloreactive TCR repertoire in the transgenic mouse was peptide dependent. However, analysis of essential TCR contacts formed during the recognition of self-MHC-restricted Ag showed that fewer contacts with peptide were established by the transgenic TCRβ chain, and that this was compensated by additional contacts formed by endogenous TCRα chains. Thus, reduced interaction with the peptide appears to be a transferable feature of the peptide-independent TCRβ chain. In addition, these findings demonstrate that reactivity to peptides is preferred over the reactivity to MHC during the formation of the TCR repertoire.
CD8+ T Cells Circumvent Immune Privilege in the Eye and Mediate Intraocular Tumor Rejection by a TNF-α-Dependent Mechanism
Authors: Dace Dru S. , Chen Peter W. , Niederkorn Jerry Y.
Published: April 2014

Although intraocular tumors reside in an immune-privileged environment, T cells can circumvent immune privilege and mediate tumor rejection without inducing damage to normal ocular tissue. In this study, we used a well-characterized tumor, Ad5E1 (adenovirus type 5 early region 1), to analyze the role of CD8+ T cells in the pristine rejection of intraocular tumors. It has been previously documented that Ad5E1 tumor rejection can occur in the absence of CD8+ T cells. However, here we find that CD8+ T cells infiltrated intraocular Ad5E1 tumors in C57BL/6 mice. Surprisingly, CD8+ T cells from tumor-rejector mice could mediate intraocular tumor rejection following adoptive transfer to SCID mice. In determining the mechanisms behind CD8+ T cell-mediated tumor rejection, we discovered that antitumor CTL activity was neither observed nor necessary for rejection of the intraocular tumors. CD8+ T cells from rejector mice did not produce IFN-γ in response to Ad5E1 tumor Ags or use FasL to mediate intraocular tumor rejection. Also, CD8+ T cells did not use perforin or TRAIL, as CD8+ T cells from perforin knockout (KO) and TRAIL KO mice conferred protection to SCID recipient mice following adoptive transfer. We discovered that CD8+ T cells used TNF-α to mediate tumor rejection, because Ad5E1 tumor cells were highly sensitive to TNF-α-induced apoptosis and CD8+ T cells from TNF-α KO mice did not protect SCID mice from progressive Ad5E1 tumor growth. The results indicate that CD8+ T cells circumvent immune privilege and mediate intraocular tumor rejection by a TNF-α-dependent manner while leaving the eye intact and vision preserved.
9-cis-Retinoic Acid (9cRA), a Retinoid X Receptor (RXR) Ligand, Exerts Immunosuppressive Effects on Dendritic Cells by RXR-Dependent Activation: Inhibition of Peroxisome Proliferator-Activated Receptor γ Blocks Some of the 9cRA Activities, and Precludes Them to Mature Phenotype Development
Authors: Zapata-Gonzalez Fernando , Rueda Félix , Petriz Jordi , Domingo Pere , Villarroya Francesc , de Madariaga Africa , Domingo Joan C.
Published: April 2014

At nanomolar range, 9-cis-retinoic acid (9cRA) was able to interfere in the normal differentiation process from human monocyte to immature dendritic cell (DC) and produced a switch in mature DCs to a less stimulatory mode than untreated cells. 9cRA-treated mature DCs secreted high levels of IL-10 with an IL-12 reduced production. The phenotypic alterations unleashed by 9cRA were similar but not identical to other specific retinoid X receptor (RXR) agonists and to those already reported for rosiglitazone, a PPARγ activator, on DCs. The simultaneous addition of 9cRA and rosiglitazone on DCs displayed additive effects. Moreover, addition to cultures of GW9662, a specific inhibitor of PPARγ, or the RXR pan-antagonist HX603, blocked these changes. All these results suggest an activation of PPARγ-RXR and other RXR containing dimers by 9cRA in DCs. Finally, both GW9662 and HX603 by themselves altered the maturation process unleashed by TNFα, poly(I:C) or LPS on human DCs further suggesting that the heterodimer PPARγ-RXR must fulfill a significant role in the physiological maturation process of these cells in addition to the repressing effects reported till now for this nuclear receptor.
Regulation by Src Homology 2 Domain-Containing Protein Tyrosine Phosphatase Substrate-1 of α-Galactosylceramide-Induced Antimetastatic Activity and Th1 and Th2 Responses of NKT Cells
Authors: Okajo Jun , Kaneko Yoriaki , Murata Yoji , Tomizawa Takeshi , Okuzawa Chie , Saito Yasuyuki , Kaneko Yuka , Ishikawa-Sekigami Tomomi , Okazawa Hideki , Ohnishi Hiroshi , Matozaki Takashi , Nojima Yoshihisa
Published: April 2014

Interaction of α-galactosylceramide (α-GalCer) presented by CD1d on dendritic cells (DCs) with the invariant TCR of NKT cells activates NKT cells. We have now investigated the role of Src homology 2 domain-containing protein tyrosine phosphatase substrate-1 (SHPS-1), a transmembrane protein abundantly expressed on DCs, in regulation of NKT cells with the use of mice that express a mutant form of SHPS-1. The suppression by α-GalCer of experimental lung metastasis was markedly attenuated in SHPS-1 mutant mice compared with that apparent in wild-type (WT) mice. The antimetastatic effect induced by adoptive transfer of α-GalCer-pulsed DCs from SHPS-1 mutant mice was also reduced compared with that apparent with WT DCs. Both the production of IFN-γ and IL-4 as well as cell proliferation in response to α-GalCer in vitro were greatly attenuated in splenocytes or hepatic mononuclear cells from SHPS-1 mutant mice compared with the responses of WT cells. Moreover, CD4+ mononuclear cells incubated with α-GalCer and CD11c+ DCs from SHPS-1 mutant mice produced markedly smaller amounts of IFN-γ and IL-4 than did those incubated with α-GalCer and CD11c+ DCs from WT mice. SHPS-1 on DCs thus appears to be essential for α-GalCer-induced antimetastatic activity and Th1 and Th2 responses of NKT cells. Moreover, our recent findings suggest that SHPS-1 on DCs is also essential for the priming of CD4+ T cells by DCs.
Distinct Endosomal Trafficking Requirements for Presentation of Autoantigens and Exogenous Lipids by Human CD1d Molecules
Authors: Chen Xiuxu , Wang Xiaohua , Keaton Jason M. , Reddington Faye , Illarionov Petr A. , Besra Gurdyal S. , Gumperz Jenny E.
Published: April 2014

CD1d molecules present both self Ags and microbial lipids to NKT cells. Previous studies have established that CD1d lysosomal trafficking is required for presentation of autoantigens to murine invariant NKT cells. We show in this study that this is not necessary for autoantigen presentation by human CD1d, but significantly affects the presentation of exogenous Ags. Wild-type and tail-deleted CD1d molecules stimulated similar autoreactive responses by human NKT clones, whereas presentation of exogenous lipids by tail-deleted CD1d was highly inefficient. Chloroquine treatment markedly inhibited exogenous Ag presentation by wild-type CD1d transfectants, but did not affect NKT autoreactive responses. Conversely, APC expression of HLA-DRαβ and the invariant chain (Ii) was associated with faster internalization of CD1d into the endocytic system and enhanced CD1d-mediated presentation of exogenous Ags, but did not appear to augment NKT autoreactivity. Knockdown of the Ii by small interfering RNA resulted in reduced CD1d surface expression and slower internalization in HLA-DR+ APCs, but not HLA-DR− APCs, demonstrating a direct effect of MHC/Ii complexes on CD1d trafficking. CD1d-mediated presentation of exogenous Ags was much more efficient in immature dendritic cells, which actively recycle MHC class II molecules through the endocytic system, than in mature dendritic cells that have stabilized MHC class II expression at the cell surface, suggesting a physiological role for MHC/Ii complexes in modulating CD1d function. These results indicate that autoantigens and exogenous lipids are acquired by human CD1d at distinct cellular locations, and that Ii trafficking selectively regulates CD1d-mediated presentation of extracellular Ags.
CD24 on the Resident Cells of the Central Nervous System Enhances Experimental Autoimmune Encephalomyelitis
Authors: Liu Jin-Qing , Carl Joseph W. , Joshi Pramod S. , RayChaudhury Abhik , Pu Xin-An , Shi Fu-Dong , Bai Xue-Feng
Published: April 2014

CD24 is a cell surface glycoprotein that is expressed on both immune cells and cells of the CNS. We have previously shown that CD24 is required for the induction of experimental autoimmune encephalomyelitis (EAE), an experimental model for the human disease multiple sclerosis (MS). The development of EAE requires CD24 expression on both T cells and non-T host cells in the CNS. To understand the role of CD24 on the resident cells in the CNS during EAE development, we created CD24 bone marrow chimeras and transgenic mice in which CD24 expression was under the control of a glial fibrillary acidic protein promotor (AstroCD24TG mice). We showed that mice lacking CD24 expression on the CNS resident cells developed a mild form of EAE; in contrast, mice with overexpression of CD24 in the CNS developed severe EAE. Compared with nontransgenic mice, the CNS of AstroCD24TG mice had higher expression of cytokine genes such as IL-17 and demyelination-associated marker P8; the CNS of AstroCD24TG mice accumulated higher numbers of Th17 and total CD4+ T cells, whereas CD4+ T cells underwent more proliferation during EAE development. Expression of CD24 in CD24-deficient astrocytes also enhanced their costimulatory activity to myelin oligodendrocyte glycoprotein-specific, TCR-transgenic 2D2 T cells. Thus, CD24 on the resident cells in the CNS enhances EAE development via costimulation of encephalitogenic T cells. Because CD24 is increased drastically on resident cells in the CNS during EAE, our data have important implications for CD24-targeted therapy of MS.
B7-2 Regulates Survival, Phenotype, and Function of APCs
Authors: Yadav Deepak , Sarvetnick Nora
Published: April 2014

The absence of B7-2-mediated costimulation protects NOD mice from the development of diabetes. Although the effects of B7-2 on T cell priming are well known, its impact on the function of APCs is not fully elucidated. We tested APC function and survival in mice lacking B7-2. A significant reduction in the phagocytic ability was observed in both splenic and pancreatic lymph node-associated dendritic cells (DCs) in B7-2 knockout (KO) mice. DCs from B7-2KO mice exhibited enhanced susceptibility to death, which was reflected by their reduced total cell numbers. Phenotypic analysis of APCs in B7-2KO mice revealed a significantly decreased proportion of CD8α+CD205+ DCs. Interestingly, an enhanced proportion of B7-H1+ and B7-DC+ DCs were observed in B7-2KO mice. Lastly, we found that B7-2 deficiency significantly diminished the PKC-ε response in APCs upon CD28-Ig stimulation. In conclusion our data suggests that B7-2 promotes the generation of a mature APC repertoire and promotes APC function and survival.