bluuebunny/crossref_metadata_2025 huggingface dataset:
Complement Is Essential for Protection by an IgM and an IgG3 Monoclonal Antibody Against Experimental, Hematogenously Disseminated Candidiasis
Authors: Han Yongmoon , Kozel Thomas R. , Zhang Mason X. , MacGill Randall S. , Carroll Michael C. , Cutler Jim E.
Published: April 2014

The incidence of life-threatening, hematogenously disseminated candidiasis, which is predominantly caused by Candida albicans, parallels the use of modern medical procedures that adversely affect the immune system. Limited antifungal drug choices and emergence of drug-resistant C. albicans strains indicate the need for novel prevention and therapeutic strategies. We are developing vaccines and Abs that enhance resistance against experimental candidiasis. However, the prevalence of serum anti-Candida Abs in candidiasis patients has led to the misconception that Abs are not protective. To explain the apparent discrepancy between such clinical observations and our work, we compared functional activities of C. albicans-specific protective and nonprotective mAbs. Both kinds of Abs are agglutinins that fix complement and are specific for cell surface mannan, but the protective Abs recognize β-mannan, and the nonprotective Ab is specific for α-mannan. By several indirect and direct measures, the protective mAbs more efficiently bind complement factor C3 to the yeast cell than do nonprotective Ab. We hypothesize that the C3 deposition causes preferential association of blood-borne fungi with host phagocytic cells that are capable of killing the fungus. We conclude from these results that the protective potential of Abs is dependent on epitope specificity, serum titer, and ability to rapidly and efficiently fix complement to the fungal surface. The mechanism of protection appears to be associated with enhanced phagocytosis and killing of the fungus.
DNA Fusion Vaccine Designed to Induce Cytotoxic T Cell Responses Against Defined Peptide Motifs: Implications for Cancer Vaccines
Authors: Rice Jason , Elliott Tim , Buchan Sarah , Stevenson Freda K.
Published: April 2014

DNA vaccination offers a strategy to induce immune attack on cancer cells, but tumor Ags are often weak. Inclusion of a “foreign” protein increases immunogenicity, and we found previously that fusion of the fragment C (FrC) of tetanus toxin to the tumor Ag sequence promotes Ab and CD4+ responses against B cell tumors. For CTL responses, use of the full two-domain FrC may be less helpful, because known immunogenic MHC class I-binding peptides in the second domain could compete with attached tumor-derived epitopes. Therefore, we removed the second domain, retaining the N-terminal domain, which contains a “universal” helper epitope. We investigated the ability to induce CTL responses of candidate peptides placed at the C terminus of this domain. As test peptides, we repositioned the two known CTL motifs from the second domain to this site. Strong CTL responses to each peptide were induced by the engineered construct, as compared with the native FrC construct. Induced CTLs were able to specifically kill tumor cells transfected with FrC as a surrogate tumor Ag both in vitro and in vivo. Further reduction of the domain to a short helper epitope generated only weak CTL responses against fused peptides, and synthetic peptides mixed with the plasmid containing the first domain were ineffective. The single FrC domain-peptide vaccine design also was able to induce high levels of CTLs against a known epitope from carcinoembryonic Ag. Response to peptide was suppressed if two FrC domains were present, consistent with immunodominance. These principles and designs may have relevance for cancer vaccines delivered via DNA.
Immunostimulatory DNA-Based Vaccines Elicit Multifaceted Immune Responses Against HIV at Systemic and Mucosal Sites
Authors: Horner Anthony A. , Datta Sandip K. , Takabayashi Kenji , Belyakov Igor M. , Hayashi Tomoko , Cinman Nadya , Nguyen Minh-Duc , Van Uden John H. , Berzofsky Jay A. , Richman Douglas D. , Raz Eyal
Published: April 2014

Immunostimulatory DNA sequences (ISS, also known as CpG motifs) are pathogen-associated molecular patterns that are potent stimulators of innate immunity. We tested the ability of ISS to act as an immunostimulatory pathogen-associated molecular pattern in a model HIV vaccine using gp120 envelope protein as the Ag. Mice immunized with gp120 and ISS, or a gp120:ISS conjugate, developed gp120-specific immune responses which included: 1) Ab production; 2) a Th1-biased cytokine response; 3) the secretion of β-chemokines, which are known to inhibit the use of the CCR5 coreceptor by HIV; 4) CTL activity; 5) mucosal immune responses; and 6) CD8 T cell responses that were independent of CD4 T cell help. Based on these results, ISS-based immunization holds promise for the development of an effective preventive and therapeutic HIV vaccine.
CCAAT-Enhancer-Binding Protein β (C/EBPβ) Activates CCR5 Promoter: Increased C/EBPβ and CCR5 in T Lymphocytes from HIV-1-Infected Individuals
Authors: Rosati Margherita , Valentin Antonio , Patenaude Daniel J. , Pavlakis George N.
Published: April 2014

C/EBPβ is a member of a family of leucine zipper transcription factors that are involved in regulating the expression of several cytokines, including IL-1, IL-6, IL-8, TNF, and macrophage-inflammatory protein-1α. We identified multiple C/EBPβ binding sites within the gene for CCR5, suggesting that C/EBPβ may be involved in its regulation. Transient transfection experiments in both myeloid and lymphoid cells showed an increase in CCR5 promoter-driven green fluorescent protein production in the presence of C/EBPβ. Deletion analysis identified two C/EBPβ-responsive regions in the CCR5 gene, one in the promoter region and one at the 3′ part of the intron. We provide evidence that, in myeloid cells (U937), C/EBPβ independently activates CCR5 expression through sites located either in the promoter region or in the intron of the CCR5 gene. In contrast, in lymphoid cells (Jurkat) the presence of the intronic cis-regulatory regions is required for C/EBPβ-mediated activation. In agreement with the functional data, EMSA demonstrated that in both myeloid and lymphoid cells C/EBPβ binds specifically to sites present in the intron, whereas interaction with the sites located in the promoter was cell type specific and was detected only in myeloid cells. Analysis of C/EBPβ in primary PBMCs obtained from HIV-1-infected individuals revealed a significant increase in C/EBPβ expression. The enhanced C/EBPβ activity correlated with a higher frequency of circulating CCR5+ lymphocytes in AIDS patients and with a decline in CD4 lymphocyte numbers. Taken together, these results suggest that C/EBPβ is an important regulator of CCR5 expression and may play a relevant role in the pathogenesis of HIV disease.
Extensive Eosinophil Degranulation and Peroxidase-Mediated Oxidation of Airway Proteins Do Not Occur in a Mouse Ovalbumin-Challenge Model of Pulmonary Inflammation
Authors: Denzler Karen L. , Borchers Michael T. , Crosby Jeffrey R. , Cieslewicz Grzegorz , Hines Edith M. , Justice J. Paul , Cormier Stephania A. , Lindenberger Kari A. , Song Wei , Wu Weijia , Hazen Stanley L. , Gleich Gerald J. , Lee James J. , Lee Nancy A.
Published: April 2014

Paradigms of eosinophil effector function in the lungs of asthma patients invariably depend on activities mediated by cationic proteins released from secondary granules during a process collectively referred to as degranulation. In this study, we generated knockout mice deficient for eosinophil peroxidase (EPO) to assess the role(s) of this abundant secondary granule protein in an OVA-challenge model. The loss of EPO had no effect on the development of OVA-induced pathologies in the mouse. The absence of phenotypic consequences in these knockout animals extended beyond pulmonary histopathologies and airway changes, as EPO-deficient animals also displayed OVA-induced airway hyperresponsiveness after provocation with methacholine. In addition, EPO-mediated oxidative damage of proteins (e.g., bromination of tyrosine residues) recovered in bronchoalveolar lavage from OVA-treated wild-type mice was <10% of the levels observed in bronchoalveolar lavage recovered from asthma patients. These data demonstrate that EPO activities are inconsequential to the development of allergic pulmonary pathologies in the mouse and suggest that degranulation of eosinophils recruited to the lung in this model does not occur at levels comparable to those observed in humans with asthma.
Increased Entry into the IFN-γ Effector Pathway by CD4+ T Cells Selected by I-Ag7 on a Nonobese Diabetic Versus C57BL/6 Genetic Background
Authors: Koarada Syuichi , Wu Yuehong , Ridgway William M.
Published: April 2014

IFN-γ-mediated Th1 effects play a major role in the pathogenesis of autoimmune diabetes in nonobese diabetic (NOD) mice. We analyzed functional responses of CD4+ T cells from NOD and B6.G7 MHC congenic mice, which share the H2g7 MHC region but differ in their non-MHC genetic background. T cells from each strain proliferated equally to panstimulation with T cell lectins as well as to stimulation with glutamic acid decarboxylase 524–543 (self) and hen egg lysozyme 11–23 (foreign) I-Ag7-binding peptide epitopes. Despite comparable proliferative responses, NOD CD4+ T cells had significantly increased IFN-γ intracellular/extracellular protein and mRNA responses compared with B6.G7 T cells as measured by intracellular cytokine analysis, time resolved fluorometry, and RNase protection assays. The increased IFN-γ production was not due to an increase in the amount of IFN-γ produced per cell but to an increase in the number of NOD CD4+ T cells entering the IFN-γ-producing pathway. The increased IFN-γ response in NOD mice was not due to increased numbers of activated precursors as measured by activation/memory markers. B6.G7 lymphoid cells demonstrated an absolute decrease in IFN-γ mRNA, an increase in IL-4 mRNA production, and a significantly decreased IFN-γ:IL-4 mRNA transcript ratio compared with NOD cells. CD4+ T cells from C57BL6 mice also showed significantly decreased IFN-γ production compared with CD4+ T cells from NOD.H2b MHC-congenic mice (which have an H2b MHC region introgressed onto an NOD non-MHC background). Therefore, the NOD non-MHC background predisposes to a quantitatively increased IFN-γ response, independent of MHC class II-mediated T cell repertoire selection, even when compared with a prototypical Th1 strain.
Administration of Pentoxifylline During Allergen Sensitization Dissociates Pulmonary Allergic Inflammation from Airway Hyperresponsiveness
Authors: Fleming Carolyn M. , He Hongzhen , Ciota Alex , Perkins David , Finn Patricia W.
Published: April 2014

Asthma, a chronic inflammatory disease characterized by intermittent, reversible airflow obstruction and airway hyperresponsiveness (AHR), is classically characterized by an excess of Th2 cytokines (IL-13, IL-4) and depletion of Th1 cytokines (IFN-γ, IL-12). Recent studies indicating an important role for Th1 immunity in the development of AHR with allergic inflammation suggest that Th1/Th2 balance may be important in determining the association of AHR with allergic inflammation. We hypothesized that administration of pentoxifylline (PTX), a phosphodiesterase inhibitor known to inhibit Th1 cytokine production, during allergen (OVA) sensitization and challenge would lead to attenuation of AHR in a murine model of allergic pulmonary inflammation. We found that PTX treatment led to attenuation of AHR when administered at the time of allergen sensitization without affecting other hallmarks of pulmonary allergic inflammation. Attenuation of AHR with PTX treatment was found in the presence of elevated bronchoalveolar lavage fluid levels of the Th2 cytokine IL-13 and decreased levels of the Th1 cytokine IFN-γ. PTX treatment during allergen sensitization leads to a divergence of AHR and pulmonary inflammation following allergen challenge.
Induction of Experimental Autoimmune Thyroiditis in IL-12−/− Mice
Authors: Chen Kemin , Wei Yongzhong , Sharp Gordon C. , Braley-Mullen Helen
Published: April 2014

Granulomatous experimental autoimmune thyroiditis (G-EAT) is induced by transfer of mouse thyroglobulin (MTg)-sensitized spleen cells activated in vitro with MTg and anti-IL-2R or MTg and IL-12. Previous work suggested that IL-12 was required in vitro for development of G-EAT. To determine whether IL-12 was also required during the induction and/or effector phases, DBA/1 mice with a disrupted IL-12-P40 gene (IL-12−/−) were used for EAT induction. Cells from MTg-sensitized IL12−/− donors activated in vitro by MTg or MTg and anti-IL2R induced severe EAT in recipient mice. Compared with effector cells from IL-12+/+ donors, effector cells from IL-12−/− donors induced thyroid lesions dominated by lymphocytes with minimal granulomatous changes. Thyroids of recipients of IL-12−/− cells expressed less IFN-γ mRNA and more TGF-β, IL-4, and IL-10 compared with recipients of IL-12+/+ cells. When IL-12 was added during in vitro activation, cells from both IL-12−/− and IL-12+/+ donors induced severe G-EAT, and expression of all cytokines except IL-12 was comparable in thyroids of both IL-12+/+ and IL-12−/− recipients. Transfer of cells from IL-12+/+ or IL-12−/− donors into IL-12+/+ or IL-12−/− recipients indicated that IL-12 expressed in thyroids was derived from recipients. Thus, endogenous IL-12 is not absolutely essential for the sensitization and activation of EAT effector cells to induce severe EAT, although it is required in vitro to promote activation of cells to induce severe granulomatous histopathology.
Allergen-Derived T Cell Peptide-Induced Late Asthmatic Reactions Precede the Induction of Antigen-Specific Hyporesponsiveness in Atopic Allergic Asthmatic Subjects
Authors: Oldfield William L. G. , Kay A. Barry , Larché Mark
Published: April 2014

Allergen-derived peptides can induce T cell tolerance in naive and Ag-primed mice. This is preceded by transient T cell activation. In humans, intradermal administration of short allergen-derived T cell peptide epitopes provokes IgE-independent isolated late asthmatic reactions (LARs) in sensitized subjects. In this study, we determine whether, as in mouse models, such peptides produce hyporesponsiveness to rechallenge with peptides, or whole allergen, either clinically or in terms of in vitro T cell responses. We found that a second injection of cat allergen (Fel d 1)-derived T cell peptides was associated with a marked reduction, or absence, of the LAR, and that up to 40 wk was required for return to baseline values. The cutaneous late-phase reaction to whole cat dander was also inhibited, even in subjects who did not experience an initial LAR. These observations were associated with a significant decrease in peptide- and whole allergen-induced proliferation of PBMCs and the production of IL-4, IL-13, and IFN-γ in cultures. Thus, allergen-derived peptides induce tolerance to subsequent peptide injection in the target organ (the lung), reduce late-phase cutaneous responsiveness to whole allergen, and alter in vitro T cell reactivity.
Short-Term Kinetics of Tumor Antigen Expression in Response to Vaccination
Authors: Ohnmacht Galen A. , Wang Ena , Mocellin Simone , Abati Andrea , Filie Armando , Fetsch Patricia , Riker Adam I. , Kammula Udai S. , Rosenberg Steven A. , Marincola Francesco M.
Published: April 2014

The melanoma patient’s immune response to tumor has been extensively studied. Yet, the frequently observed coexistence of tumor-associated Ag (TAA)-specific T cells with their target cells in vivo remains unexplained. Loss of TAA expression might contribute to this paradox. We studied TAA expression in metastases by obtaining fine-needle aspirations from 52 tumor lesions in 30 patients with melanoma before and soon after immunotherapy. Limitations due to low amounts of starting material were overcome with a high fidelity antisense RNA amplification method. TAA expression was measured by quantitative real-time PCR of anti-sense RNA. Decrease in gp100/Pmel-17 TAA preceded tumor disappearance in several instances and could be best explained by immune selection because most patients had received gp100/Pmel-17-specific vaccination. Conversely, immune selection was absent in nonregressing lesions. These observations suggest that vaccination, when successful, triggers a broad inflammatory reaction that can lead to tumor destruction despite immune selection. Additionally, lack of clinical response might be attributed to lack of this initiating event rather than immune escape. This study provides an insight into the natural history of tumors and defines a strategy for the characterization of gene expression in tumors during therapy.
Intrathecal Delivery of IFN-γ Protects C57BL/6 Mice from Chronic-Progressive Experimental Autoimmune Encephalomyelitis by Increasing Apoptosis of Central Nervous System-Infiltrating Lymphocytes
Authors: Furlan Roberto , Brambilla Elena , Ruffini Francesca , Poliani Pietro L. , Bergami Alessandra , Marconi Peggy C. , Franciotta Diego M. , Penna Giuseppe , Comi Giancarlo , Adorini Luciano , Martino Gianvito
Published: April 2014

The exclusive detrimental role of proinflammatory cytokines in demyelinating diseases of the CNS, such as multiple sclerosis, is controversial. Here we show that the intrathecal delivery of an HSV-1-derived vector engineered with the mouse IFN-γ gene leads to persistent (up to 4 wk) CNS production of IFN-γ and inhibits the course of a chronic-progressive form of experimental autoimmune encephalomyelitis (EAE) induced in C57BL/6 mice by myelin oligodendrocyte glycoprotein (MOG)35–55. Mice treated with the IFN-γ-containing vector before EAE onset showed an earlier onset but a milder course of the disease compared with control mice treated with the empty vector. In addition, 83% of IFN-γ-treated mice completely recovered within 25 days post immunization, whereas control mice did not recover up to 60 days post immunization. Mice treated with the IFN-γ-containing vector within 1 wk after EAE onset partially recovered from the disease within 25 days after vector injection, whereas control mice worsened. Recovery from EAE in mice treated with IFN-γ was associated with a significant increase of CNS-infiltrating lymphocytes undergoing apoptosis. During the recovery phase, the mRNA level of TNFR1 was also significantly increased in CNS-infiltrating cells from IFN-γ-treated mice compared with controls. Our results further challenge the exclusive detrimental role of IFN-γ in the CNS during EAE/multiple sclerosis, and indicate that CNS-confined inflammation may induce protective immunological countermechanisms leading to a faster clearance of encephalitogenic T cells by apoptosis, thus restoring the immune privilege of the CNS.
Cutting Edge: T Cell Migration Regulated by CXCR4 Chemokine Receptor Signaling to ZAP-70 Tyrosine Kinase
Authors: Ottoson Nadine C. , Pribila Jonathan T. , Chan Anissa S. H. , Shimizu Yoji
Published: April 2014

Chemokines regulate the homeostatic trafficking of lymphocytes and lymphocyte influx into sites of injury and inflammation. The signaling pathways by which chemokine receptors regulate lymphocyte migration remain incompletely characterized. We demonstrate that Jurkat T cells lacking the ZAP-70 tyrosine kinase exhibit reduced migration in response to the CXCR4 ligand CXCL12 when compared with wild-type Jurkat T cells. Expression of wild-type, but not kinase-inactive, ZAP-70 resulted in enhanced migration of ZAP-70-deficient Jurkat T cells. The tyrosine residue at position 292 in the interdomain B region of ZAP-70 exerts a negative regulatory effect on ZAP-70-dependent migration. Stimulation of Jurkat T cells with CXCL12 also resulted in ZAP-70-dependent tyrosine phosphorylation of the Src homology 2 domain-containing leukocyte protein of 76 kDa (SLP-76) adapter protein. Although CXCL12-dependent migration of SLP-76-deficient Jurkat T cells was impaired, re-expression of SLP-76 did not enhance migration. These results suggest a novel function for ZAP-70, but not SLP-76, in CXCR4 chemokine receptor signaling in human T cells.
Cutting Edge: Predominant Expression of a Novel Ikaros Isoform in Normal Human Hemopoiesis
Authors: Payne Kimberly J. , Nicolas Jan-Holly , Zhu Judy Y. , Barsky Lora W. , Crooks Gay M.
Published: April 2014

Murine studies implicate Ikaros proteins as regulators of hemopoiesis, particularly in the lymphoid lineages. High homology between murine and human Ikaros suggests that Ikaros expression in the two might be similar. However, initial human studies that focused on leukemia detected novel Ikaros transcripts in patient samples. Thus, novel Ikaros splice forms and DNA nonbinding isoforms were linked with malignancy. We undertook an extensive analysis of normal human Ikaros expression to determine whether novel mRNAs are expressed as proteins and the extent to which these splice variants are unique to leukemia. Here we show that both mRNA and protein for DNA nonbinding Ikaros isoforms and splice variants previously linked to leukemia are expressed in normal human cells. However, our studies identify a new Ikaros isoform not previously described in mouse or human. This isoform is the predominant Ikaros protein in normal human cells, but not in leukemia cell lines.
Cutting Edge: Induction of IFN-γ Production but Not Cytotoxicity by the Killer Cell Ig-Like Receptor KIR2DL4 (CD158d) in Resting NK Cells
Authors: Rajagopalan Sumati , Fu Jacqueline , Long Eric O.
Published: April 2014

Activated NK cells lyse tumor cells and virus-infected cells and produce IFN-γ upon contact with sensitive target cells. The regulation of these effector responses in resting NK cells is not well understood. We now describe a receptor, KIR2DL4, that has the unique property of inducing IFN-γ production, but not cytotoxicity, by resting NK cells in the absence of cytokines. In contrast, the NK cell-activation receptors CD16 and 2B4 induced cytotoxicity but not IFN-γ production. The induction by KIR2DL4 of IFN-γ production by resting NK cells was blocked by an inhibitor of the p38 mitogen-activated protein kinase signaling pathway, in contrast to the IL-2-induced IFN-γ secretion that was sensitive to inhibition of the extracellular signal-regulated kinase mitogen-activated protein kinase pathway. These results reveal a functional dichotomy (cytokine production vs cytotoxicity) in the response of resting NK cells, as dictated by the signals of individual receptors.
Cutting Edge: Expansion and Activation of A Population of Autoreactive Marginal Zone B Cells in a Model of Estrogen-Induced Lupus
Authors: Grimaldi Christine M. , Michael Daniel J. , Diamond Betty
Published: April 2014

We have demonstrated previously that 17 β-estradiol (E2) treatment of BALB/c mice transgenic for the heavy chain of a pathogenic anti-DNA Ab induces a lupus-like phenotype with expansion of anti-DNA B cells, elevation of anti-DNA Ab titers, and glomerular immunoglobulin deposition. To understand this loss of B cell tolerance, the effects of E2 on B cell development and activation were examined. A sustained increase in E2 resulted in an altered distribution of B cell subsets, with a diminished transitional population and an increase in marginal zone B cells. Depletion of CD4+ T cells did not abrogate these effects. Furthermore, the B cells that spontaneously secreted anti-DNA Abs displayed a marginal zone phenotype. Thus, a sustained increase in E2 alters B cell development, leading to the survival, expansion, and activation of a population of autoreactive marginal zone B cells implicating this B cell subset in autoimmunity.
Role of CD4+ and CD8+ T Cells in Allorecognition: Lessons from Corneal Transplantation
Authors: Boisgérault Florence , Liu Ying , Anosova Natalie , Ehrlich Elana , Dana M. Reza , Benichou Gilles
Published: April 2014

Corneal transplantation represents an interesting model to investigate the contribution of direct vs indirect Ag recognition pathways to the alloresponse. Corneal allografts are naturally devoid of MHC class II+ APCs. In addition, minor Ag-mismatched corneal grafts are more readily rejected than their MHC-mismatched counterparts. Accordingly, it has been hypothesized that these transplants do not trigger direct T cell alloresponse, but that donor Ags are presented by host APCs, i.e., in an indirect fashion. Here, we have determined the Ag specificity, frequency, and phenotype of T cells activated through direct and indirect pathways in BALB/c mice transplanted orthotopically with fully allogeneic C57BL/6 corneas. In this combination, only 60% of the corneas are rejected, while the remainder enjoy indefinite graft survival. In rejecting mice the T cell response was mediated by two T cell subsets: 1) CD4+ T cells that recognize alloantigens exclusively through indirect pathway and secrete IL-2, and 2) IFN-γ-producing CD8+ T cells recognizing donor MHC in a direct fashion. Surprisingly, CD8+ T cells activated directly were not required for graft rejection. In nonrejecting mice, no T cell responses were detected. Strikingly, peripheral sensitization to allogeneic MHC molecules in these mice induced acute rejection of corneal grafts. We conclude that only CD4+ T cells activated via indirect allorecognition have the ability to reject allogeneic corneal grafts. Although alloreactive CD8+ T cells are activated via the direct pathway, they are not fully competent and cannot contribute to the rejection unless they receive an additional signal provided by professional APCs in the periphery.
Human Cytomegalovirus Circumvents NF-κB Dependence in Retinal Pigment Epithelial Cells
Authors: Cinatl Jindrich , Margraf Stefan , Vogel Jens-Uwe , Scholz Martin , Cinatl Jaroslav , Doerr Hans Wilhelm
Published: April 2014

The human CMV (HCMV) is a persistent virus that may cause severe inflammatory responses especially in immunocompromised hosts. In different cell types, HCMV infection leads to the activation of the pleiotropic transcription factor, NF-κB, which triggers virus replication but also propagates cell-mediated inflammatory mechanisms that largely depend on PG synthesis. We investigated the interactions of HCMV and the NF-κB-dependent PG synthesis pathway in cultures of retinal pigment epithelial (RPE) cells that are known to be infected in HCMV retinitis patients. Unlike in other cell types, HCMV increased neither NF-κB activity nor p65 and p105/50 mRNA levels in RPE cells. Both TNF-α and phorbol ester 12,0-tetradecanoylphorbol 13-acetate (TPA) enhanced NF-κB activity but only TPA increased HCMV replication. Cyclooxygenase-2 expression and PGE2 release was increased by TPA and TNF-α but not by HCMV infection. Stimulatory activity of TPA on HCMV replication was suppressed by protein kinase C inhibitors and inhibitors of p42/44 and p38 mitogen-activated protein kinases but not by NF-κB inhibitors. In conclusion, HCMV circumvents the NF-κB route in favor of the protein kinase C-dependent mitogen-activated protein kinase pathway in RPE cells. This virus/host cell interaction might be a mechanism that promotes HCMV persistence in immune-privileged organs such as the eye.
Differential Roles of Cytokine Receptors in the Development of Epidermal γδ T Cells
Authors: Ye Sang-Kyu , Maki Kazushige , Lee Hai-Chon , Ito Akiko , Kawai Kazuhiro , Suzuki Haruhiko , Mak Tak W. , Chien Yueh-hsiu , Honjo Tasuku , Ikuta Koichi
Published: April 2014

IL-7 and IL-15 play important roles in γδ T cell development. These receptors transmit proliferation and/or survival signals in γδ T cells. In addition, the IL-7R promotes recombination and transcription in the TCR γ locus. To clarify the role of the cytokine receptors in the development of epidermal γδ T cells, we introduced a Vγ3/Vδ1 TCR transgene, derived from Thy-1+ dendritic epidermal T cells (DETC), into IL-7Rα-deficient mice, and we found that they partly rescued γδ T cells in the adult thymus but not in the spleen. Introduction of an additional Bcl-2 transgene had a minimal effect on γδ T cells in the adult thymus of these mice. In contrast to the adult thymus, the introduction of the Vγ3/Vδ1 TCR transgene into IL-7Rα−/− mice completely restored Vγ3+ T cells in the fetal thymus and DETC in the adult skin. On the contrary, the same Vγ3/Vδ1 TCR transgene failed to rescue DETC in the skin of IL-2Rβ-deficient mice, even with the additional Bcl-2 transgene. These results suggest that the IL-2/IL-15R, rather than the IL-7R, plays an essential role in proliferation and survival of DETC in the fetal thymus and the skin. In contrast, the IL-7R is probably essential in the induction of V-J recombination of TCRγ genes. Thus, this study proves that IL-7R and IL-2/IL-15R serve differential functions in epidermal γδ T cell development.
Impairment in the Expression and Activity of Fyn During Differentiation of Naive CD4+ T Cells into the Th2 Subset
Authors: Tamura Toshiki , Igarashi Osamu , Hino Ayako , Yamane Hidehiro , Aizawa Shinichi , Kato Takuma , Nariuchi Hideo
Published: April 2014

We previously showed that the amounts of Fyn protein in Th2 clones were approximately one-third to one-fifth of those in Th1 clones. In this study we examined the role of Fyn in the polarization of naive CD4+ T cells toward the Th2 subset using fyn−/− mice. The fyn−/− naive CD4+ T cells efficiently produced Th2 cytokines and polarized toward the Th2 subset even in the absence of IL-4 and IL-13. The expression of Fyn in wild-type CD4+ T cells decreased at a transcription level concomitant with polarization toward the Th2 subset. These results suggest that Fyn plays a role in the down-regulation of the differentiation of naive CD4+ T cells into the Th2 subset.
Impairment of Bleomycin-Induced Lung Fibrosis in CD28-Deficient Mice
Authors: Okazaki Tatsuma , Nakao Atsuhito , Nakano Hiroyasu , Takahashi Fumiyuki , Takahashi Kazuhisa , Shimozato Osamu , Takeda Kazuyoshi , Yagita Hideo , Okumura Ko
Published: April 2014

Lung fibrosis is an important pulmonary disease with a high mortality rate, but its pathophysiological mechanism has not been fully clarified. Various types of cells have been implicated in the development of lung fibrosis, including T cells. However, the contribution of functional molecules expressed on T cells to the development of lung fibrosis remains largely unknown. In this study, we determined whether costimulation via CD28 on T cells was crucial for the development of lung fibrosis by intratracheally administering bleomycin into CD28-deficient mice. Compared with wild-type mice, the CD28-deficient mice showed markedly impaired lung fibrosis after injection with low doses of bleomycin, as judged by histological changes and hydroxyproline content in the lungs. In addition, bleomycin-induced T cell infiltration into the airways and production of several cytokines and chemokines including IL-5 were also impaired in the CD28-deficient mice. Furthermore, adoptive transfer of CD28-positive T cells from wild-type mice recovered the impaired bleomycin-induced lung fibrosis in CD28-deficient mice. These findings suggest that the CD28-mediated T cell costimulation plays a critical role in the development of lung fibrosis, possibly by regulating the production of cytokines and chemokines in the lung. Thus, manipulation of the CD28-mediated costimulation could be a potential therapeutic strategy for the prevention of lung fibrosis.
CD8− Dendritic Cell Activation Status Plays an Integral Role in Influencing Th2 Response Development
Authors: MacDonald Andrew S. , Straw Amy D. , Bauman Beverley , Pearce Edward J.
Published: April 2014

Whether dendritic cells (DC) play a passive or active role in Th2 response induction is poorly understood. In this study, we show that CD8− DC pulsed with Th2-polarizing Ag (soluble egg Ag (SEA)) from Schistosoma mansoni potently stimulate Th2 responses in vivo and in vitro while failing to undergo a conventional maturation process. Thus, in contrast to DC pulsed with the Th1 response inducing Ag Propionebacterium acnes, SEA-exposed DC exhibit a phenotype that is most similar to that of immature DC, failing to up-regulate expression of CD40, CD54, CD80, CD86, or OX40L; producing no detectable IL-4, IL-10, or IL-12; and displaying only a minor increase in MHC class II expression. Importantly, in vitro derived DC exposed to SEA were phenotypically similar to CD8− DC isolated from active S. mansoni infection. By discriminating between different types of pathogen and responding appropriately, CD8− DC play a major role in the decision process to mount either a Th1 or Th2 response.
The Source of Early IFN-γ That Plays a Role in Th1 Priming
Authors: Das Gobardhan , Sheridan Scott , Janeway Charles A.
Published: April 2014

When naive CD4 T cells are primed, they rapidly differentiate into polarized Th1 and/or Th2 phenotypes. A major factor in producing such polarization is the early production of cytokines (IL-12 and IFN-γ in the case of Th1 cells and IL-4 in the case of Th2 cells). One issue that remains unresolved is the source of the early IFN-γ that synergizes with IL-12 to fully polarize CD4 T cells into Th1 cells. We have examined this question by injecting mice with anti-CD3 and examining cells from normal and various MHC-knockout mice. We found that IFN-γ is induced rapidly in a small subset of CD8 T cells. This subset is absent in mice that lack β2-microglobulin, but not in KbDb-double-knockout mice, indicating that these CD8 T cells are dependent on nonclassical MHC class Ib molecules. The early burst of IFN-γ polarizes CD4 T cells toward Th1 cells, in part by stimulating the release of IL-12 from APC. We also use TAP- and CD1-knockout mice to show that such cells are not CD1-restricted NK T cells, nor are they dependent on TAP-1 transport for surface expression of the relevant MHC class Ib molecule. Therefore, they arise on MHC class Ib molecules that do not depend on TAP-1 transporters.
EBV-Specific CD8+ T Cell Memory: Relationships Between Epitope Specificity, Cell Phenotype, and Immediate Effector Function
Authors: Hislop Andrew D. , Gudgeon Nancy H. , Callan Margaret F. C. , Fazou Chrysoula , Hasegawa Hitoshi , Salmon Michael , Rickinson Alan B.
Published: April 2014

EBV infection in humans induces CD8+ T cell memory to viral epitopes derived from both lytic and latent cycle Ags. We have analyzed the relationship between the phenotype and function of the memory pool of T cells specific for these Ags. Lytic epitope-specific populations were heterogeneous in terms of CD45RO/RA and CD28 expression, whereas latent epitope-specific populations were uniformly CD45RO+ and CD28+, consistent with the higher antigenic challenge from lytic epitopes driving some memory cells toward a CD45RA+, CD28− phenotype. However, both types of memory population showed immediate epitope-specific cytotoxicity and type 1 cytokine production in ex vivo assays. Cytotoxic function was not associated with preactivated T cells, as EBV-specific populations were negative for activation markers such as CD69 or CD38, nor could cytotoxic function be ascribed to CD27− or CD56+ subsets, as such cells were not detected in EBV-specific memory. Furthermore, cytotoxicity was not limited to CD45RA+ and/or CD28− fractions, but also was observed in CD45RO+, CD28+ populations in lytic and latent epitope-specific memory. Cytokine (IFN-γ, TNF-α) responses, measured by intracytoplasmic staining after peptide stimulation, also were detectable in CD45RO+ and RA+ subsets as well as CD28+ and CD28− subsets. Of other markers that were heterogeneous in both lytic and latent epitope populations, CCR7 gave the best discrimination of functionality; thus, CCR7+ cells consistently failed to give an IFN-γ or TNF-α response, whereas many CCR7− cells were responsive. Our data are consistent with effector functions having a broad distribution among phenotypically distinct subsets of “effector memory” cells that have lost the CCR7 marker.
A Central Role for Death Receptor-Mediated Apoptosis in the Rejection of Tumors by NK Cells
Authors: Screpanti Valentina , Wallin Robert P. A. , Ljunggren Hans-Gustaf , Grandien Alf
Published: April 2014

NK cells provide a line of defense against tumors and virus-infected cells that have lost the expression of one or more MHC class I isoforms. Here, we investigate whether inhibitors of apoptosis can block the rejection of tumors mediated by NK cells, by introducing the long form of Fas-associated death domain-like IL-1β-converting enzyme-associated inhibitory protein (FLIPL) and poxvirus cytokine response modifier A (CrmA) into the MHC class I-deficient T lymphoma cell line RMA-S. RMA-S cells do not normally express Fas in vitro, and it was previously postulated that the rejection of these tumors by NK cells is strictly perforin dependent. We show that perforin-deficient NK cells directly mediate Fas up-regulation on RMA-S cells and thereafter kill the cells in a Fas-dependent manner, and that RMA-S FLIPL and RMA-S CrmA are protected from such killing. When injected in immunocompetent recipients, RMA-S cells up-regulate Fas, rendering in vivo-passed mock-transduced cells sensitive to Fas-mediated apoptosis. Moreover, RMA-S FLIPL and RMA-S CrmA cells establish aggressive tumors, in contrast to RMA-S mock cells that are rejected. These results demonstrate that FLIPL and CrmA function as tumor progression factors by protecting MHC class I-deficient tumors from rejection mediated by NK cells. Moreover, our data indicate that death receptor-mediated apoptosis has a more prominent role in the clearance of NK-sensitive tumors than previously suggested.
IL-17 Mobilizes Peripheral Blood Stem Cells with Short- and Long-Term Repopulating Ability in Mice
Authors: Schwarzenberger Paul , Huang Weitao , Oliver Peter , Byrne Patrick , La Russa Vincent , Zhang Zili , Kolls Jay K.
Published: April 2014

Autologous and allogeneic bone marrow transplantations have evolved as important cancer therapy modalities. For both indications, peripheral blood has been shown to have distinct advantages over bone marrow as the stem cell source. Cytokine combinations for mobilization have enhanced stem cell yield and accelerated engraftment. However, novel mobilizing agents and strategies are needed to further improve clinical outcomes. Within the donor graft, the dynamic equilibrium between T cells and stem cells critically influences engraftment and transplantation results. IL-17 is a cytokine produced almost exclusively from activated T cells. IL-17 was expressed in vivo with adenovirus technology. Here, proof-of-principle studies demonstrate that IL-17 effectively mobilizes hemopoietic precursor cells (CFU-granulocyte-erythrocyte-macrophage-monocyte, CFU-high proliferative potential) and primitive hemopoietic stem cells (Lin−/lowc-kit+Sca1+). Moreover, mouse IL-17 adenovirus-mobilized peripheral blood stem cells rescued lethally irradiated mice. Bone marrow was found to be 45–75% of donor origin at 1 year. In secondary recipients, donor-derived bone marrow cells ranged from 45 to 95%. These data show that IL-17 mobilizes stem cells in mice with short- and long-term reconstituting capacity. Additional comparative studies are needed as well as studies in tumor models to refine distinct potential clinical applications for IL-17-mobilized peripheral blood stem cells.
Predominance of NK1.1+TCRαβ+ or DX5+TCRαβ+ T Cells in Mice Conditioned with Fractionated Lymphoid Irradiation Protects Against Graft-Versus-Host Disease: “Natural Suppressor” Cells
Authors: Lan Fengshuo , Zeng Defu , Higuchi Masanori , Huie Philip , Higgins John P. , Strober Samuel
Published: April 2014

We developed a nonmyeloablative host conditioning regimen in a mouse model of MHC-mismatched bone marrow transplantation that not only reduces radiation toxicity, but also protects against graft-vs-host disease. The regimen of fractionated irradiation directed to the lymphoid tissues and depletive anti-T cell Abs results in a marked change in the residual host T cells, such that NK1.1+ or DX5+asialo-GM1+ T cells become the predominant T cell subset in the lymphoid tissues of C57BL/6 and BALB/c mice, respectively. The latter “natural suppressor” T cells protect hosts from graft-vs-host disease after the infusion of allogeneic bone marrow and peripheral blood cells that ordinarily kill hosts conditioned with sublethal or lethal total body irradiation. Protected hosts become stable mixed chimeras, but fail to show the early expansion and infiltration of donor T cells in the gut, liver, and blood associated with host tissue injury. Cytokine secretion and adoptive transfer studies using wild-type and IL-4−/− mice showed that protection afforded by NK1.1+ and DX5+asialo-GM1+ T cells derived from either donors or hosts conditioned with lymphoid irradiation is dependent on their secretion of high levels of IL-4.
Tapasin Enhances Peptide-Induced Expression of H2-M3 Molecules, but Is Not Required for the Retention of Open Conformers
Authors: Lybarger Lonnie , Yu Yik Yeung L. , Chun Taehoon , Wang Chyung-Ru , Grandea Andres G. , Van Kaer Luc , Hansen Ted H.
Published: April 2014

H2-M3 is a class Ib MHC molecule that binds a highly restricted pool of peptides, resulting in its intracellular retention under normal conditions. However, addition of exogenous M3 ligands induces its escape from the endoplasmic reticulum (ER) and, ultimately, its expression at the cell surface. These features of M3 make it a powerful and novel model system to study the potentially interrelated functions of the ER-resident class I chaperone tapasin. The functions ascribed to tapasin include: 1) ER retention of peptide-empty class I molecules, 2) TAP stabilization resulting in increased peptide transport, 3) direct facilitation of peptide binding by class I, and 4) peptide editing. We report in this study that M3 is associated with the peptide-loading complex and that incubation of live cells with M3 ligands dramatically decreased this association. Furthermore, high levels of open conformers of M3 were efficiently retained intracellularly in tapasin-deficient cells, and addition of exogenous M3 ligands resulted in substantial surface induction that was enhanced by coexpression of either membrane-bound or soluble tapasin. Thus, in the case of M3, tapasin directly facilitates intracellular peptide binding, but is not required for intracellular retention of open conformers. As an alternative approach to define unique aspects of M3 biosynthesis, M3 was expressed in human cell lines that lack an M3 ortholog, but support expression of murine class Ia molecules. Unexpectedly, peptide-induced surface expression of M3 was observed in only one of two cell lines. These results demonstrate that M3 expression is dependent on a unique factor compared with class Ia molecules.
A Point Mutation in the IL-12Rβ2 Gene Underlies the IL-12 Unresponsiveness of Lps-Defective C57BL/10ScCr Mice
Authors: Poltorak Alexander , Merlin Thomas , Nielsen Peter J. , Sandra Olivier , Smirnova Irina , Schupp Ingo , Boehm Thomas , Galanos Chris , Freudenberg Marina A.
Published: April 2014

Lps-defective C57BL/10ScCr (Cr) mice are homozygous for a deletion encompassing Toll-like receptor 4 that makes them refractory to the biological activity of LPS. In addition, these mice exhibit an inherited IL-12 unresponsiveness resulting in impaired IFN-γ responses to different microorganisms. By positional cloning methods, we show here that this second defect of Cr mice is due to a mutation in a single gene located on mouse chromosome 6, in close proximity to the Igκ locus. The gene is IL-12Rβ2. Cr mice carry a point mutation creating a stop codon that is predicted to cause premature termination of the translated IL-12Rβ2 after a lysine residue at position 777. The truncated β2 chain can still form a heterodimeric IL-12R that allows phosphorylation of Janus kinase 2, but, unlike the wild-type IL-12R, can no longer mediate phosphorylation of STAT4. Because the phosphorylation of STAT4 is a prerequisite for the IL-12-mediated induction of IFN-γ, its absence in Cr mice is responsible for their defective IFN-γ response to microorganisms.
Isolation and Characterization of a Novel IgD-Binding Protein fromMoraxella catarrhalis
Authors: Forsgren Arne , Brant Marta , Möllenkvist Andrea , Muyombwe Anthony , Janson Håkan , Woin Nicolas , Riesbeck Kristian
Published: April 2014

A novel surface protein of the bacterial species Moraxella catarrhalis that displays a high affinity for IgD (MID) was solubilized in Empigen and isolated by ion exchange chromatography and gel filtration. The apparent molecular mass of monomeric MID was estimated to ∼200 kDa by SDS-PAGE. The mid gene was cloned and expressed in Escherichia coli. The complete mid nucleotide gene sequence was determined, and the deduced amino acid sequence consists of 2123 residues. The sequence of MID has no similarity to other Ig-binding proteins and differs from all previously described outer membrane proteins of M. catarrhalis. MID was found to exhibit unique Ig-binding properties. Thus, in ELISA, dot blots, and Western blots, MID bound two purified IgD myeloma proteins, four IgD myeloma sera, and finally one IgD standard serum. No binding of MID was detected to IgG, IgM, IgA, or IgE myeloma proteins. MID also bound to the surface-expressed B cell receptor IgD, but not to other membrane molecules on human PBLs. This novel Ig-binding reagent promises to be of theoretical and practical interest in immunological research.
E2A and HEB Activate the Pre-TCRα Promoter During Immature T Cell Development
Authors: Takeuchi Arata , Yamasaki Sho , Takase Kan , Nakatsu Fubito , Arase Hisashi , Onodera Makoto , Saito Takashi
Published: April 2014

The pre-TCRα (pTα) is exclusively expressed in immature thymocytes and constitutes the pre-TCR complex with TCRβ, which regulates early T cell differentiation. Despite the recent identification of the pTα enhancer, the contribution of the promoter region, the direct DNA-protein interaction, and the regulation of such interaction along with T cell development have not been investigated. We analyzed the pTα promoter region and identified the critical elements for transcription of the pTα gene. The pTα promoter was found to contain two consecutive E-box elements that are critical for pTα transcription. The E-box elements in the promoter region formed the specific DNA-protein complex that was exclusively observed in immature thymocytes, not in mature thymocytes and T cells. The E proteins in this complex were identified as E2A and HeLa E-box binding protein (HEB), and overexpression of E2A and HEB resulted in activation of the pTα promoter. The binding complex in the consecutive E-boxes in the pTα promoter changed along with T cell development, as a distinct DNA-binding complex was observed in mature T cells. Comparing the E-box regions in the enhancer and the promoter, those in the promoter appear to make a greater contribution to pTα gene transcription.
Mycobacterial Lysocardiolipin Is Exported from Phagosomes upon Cleavage of Cardiolipin by a Macrophage-Derived Lysosomal Phospholipase A2
Authors: Fischer Karsten , Chatterjee Delphi , Torrelles Jordi , Brennan Patrick J. , Kaufmann Stefan H. E. , Schaible Ulrich E.
Published: April 2014

Pathogenic mycobacteria are able to survive and proliferate in phagosomes within host macrophages (Mφ). This capability has been attributed in part to their cell wall, which consists of various unique lipids. Some of these are important in the host-pathogen interaction, such as resistance against microbicidal effector mechanisms and modulation of host cell functions, and/or are presented as Ags to T cells. Here we show that two lipids are released from the mycobacterial cell wall within the phagosome of infected Mφ and transported out of this compartment into intracellular vesicles. One of these lipids was identified as lysocardiolipin. Lysocardiolipin was generated through cleavage of mycobacterial cardiolipin by a Ca2+-independent phospholipase A2 present in Mφ lysosomes. This result indicates that lysosomal host cell enzymes can interact with released mycobacterial lipids to generate new products with a different intracellular distribution. This represents a novel pathway for the modification of bacterial lipid Ags.