bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activated Self-MHC-Reactive T Cells Have the Cytokine Phenotype of Th3/T Regulatory Cell 1 T Cells
Authors: Kitani Atsushi , Chua Kevin , Nakamura Kazuhiko , Strober Warren 
Published: April 2014

AbstractIn the present study, we show that human self-MHC-reactive (autoreactive) T cell clones are functionally distinct from Ag-specific T cell clones. Self-MHC-reactive T cells exhibited helper function for B cell Ig production when cultured with non-T cells alone, and they exhibit suppressor function when cultured with PWM- or rCD40 ligand (rCD40L)-activated non-T cells, whereas tetanus toxoid (TT)-specific clones exhibited only helper function in the presence of TT with or without PWM or rCD40L. Addition of neutralizing Abs to the cultures showed that the suppression was mediated by TGF-β but not by IL-10 or IFN-γ. The self-MHC-reactive clones also inhibited proliferation of primary CD4+ T cells and TT-specific T cell clones, but in this case the inhibition was mediated by both IL-10 and TGF-β. In further studies, the interactions between self-MHC-reactive T cell clones and non-T cells that led to suppressor cytokine production have been explored. We found that prestimulation of non-T cells for 8 h with PWM or for 48 h for rCD40L results in non-T cells capable of inducing self-MHC-reactive T cell to produce high levels of TGF-β and IL-10. In addition, these prestimulation times coincided with peak induction of HLA-DR and costimulatory B7 molecule (especially CD86) expression on B cells. Finally, addition of CTLA-4/Fc or blocking F(ab′)2 anti-CTLA-4 mAb, plus optimally stimulated non-T cells, to cultures of self-MHC-reactive clones inhibited the induction of TGF-β but not IL-10 or IFN-γ production. In summary, these studies show that activated self-MHC-reactive T cells have the cytokine phenotype of Th3 or T regulatory cell 1 and thus may be important regulatory cells that mediate oral and peripheral tolerance and prevent the development of autoimmunity.
Human Uveal Melanoma Cells Produce Macrophage Migration-Inhibitory Factor to Prevent Lysis by NK Cells
Authors: Repp Amanda C. , Mayhew Elizabeth S. , Apte Sherine , Niederkorn Jerry Y. 
Published: April 2014

AbstractHuman uveal melanoma arises in an immune privileged ocular environment in which both adaptive and innate immune effector mechanisms are suppressed. Uveal melanoma is the most common intraocular tumor in adults and is derived from tissues in the eye that produce macrophage migration-inhibitory factor (MIF), a cytokine that has recently been demonstrated to produce immediate inhibition of NK cell-mediated lytic activity. Although NK cell-mediated lysis of uveal melanomas is inhibited in the eye, melanoma cells that disseminate from the eye are at risk for surveillance by NK cells. Moreover, uveal melanoma cells demonstrate a propensity to metastasize to the liver, an organ with one of the highest levels of NK activity in the body. Therefore, we speculated that uveal melanomas produced MIF as a means of escaping NK cell-mediated lysis. Accordingly, seven primary uveal melanoma cell lines and two cell lines derived from uveal melanoma metastases were examined for their production of MIF. MIF was detected in melanoma culture supernatants by both ELISA and the classical bioassay of macrophage migration inhibition. Melanoma-derived MIF inhibited NK cell-mediated lysis of YAC-1 and uveal melanoma cells. Cell lines derived from uveal melanoma metastases produced approximately twice as much biologically active MIF as cultures from primary uveal melanomas. Inhibition of NK cell-mediated killing by uveal melanoma-derived MIF was specifically inhibited in a dose-dependent manner by anti-MIF Ab. The results suggest that human uveal melanoma cells maintain a microenvironment of immune privilege by secreting active MIF that protects against NK cell-mediated killing.
Activation of Antigen-Specific CD4+ Th2 Cells and B Cells In Vivo Increases Norepinephrine Release in the Spleen and Bone Marrow
Authors: Kohm Adam P. , Tang Yueming , Sanders Virginia M. , Jones Stephen B. 
Published: April 2014

AbstractThe neurotransmitter norepinephrine (NE) binds to the β2-adrenergic receptor (β2AR) expressed on various immune cells to influence cell homing, proliferation, and function. Previous reports showed that NE stimulation of the B cell β2AR is necessary for the maintenance of an optimal primary and secondary Th2 cell-dependent Ab response in vivo. In the present study we investigated the mechanism by which activation of Ag-specific CD4+ Th2 cells and B cells in vivo by a soluble protein Ag increases NE release in the spleen and bone marrow. Our model system used scid mice that were reconstituted with a clone of keyhole limpet hemocyanin-specific Th2 cells and trinitrophenyl-specific B cells. Following immunization, the rate of NE release in the spleen and bone marrow was determined using [3H]NE turnover analysis. Immunization of reconstituted scid mice with a cognate Ag increased the rate of NE release in the spleen and bone marrow 18–25 h, but not 1–8 h, following immunization. In contrast, immunization of mice with a noncognate Ag had no effect on the rate of NE release at any time. The cognate Ag-induced increase in NE release was partially blocked by ganglionic blockade with chlorisondamine, suggesting a role for both pre- and postganglionic signals in regulating NE release. Thus, activation of Ag-specific Th2 cells and B cells in vivo by a soluble protein Ag increases the rate of NE release and turnover in the spleen and bone marrow 18–25 h after immunization.
Involvement of an ATP-Dependent Peptide Chaperone in Cross-Presentation After DNA Immunization
Authors: Kumaraguru Udayasankar , Rouse Richard J. D. , Nair Smita K. , Bruce Barry D. , Rouse Barry T. 
Published: April 2014

AbstractImmunization with plasmid DNA holds promise as a vaccination strategy perhaps useful in situations that currently lack vaccines, since the major means of immune induction may differ from more conventional approach. In the present study, we demonstrate that exposure of macrophages to plasmid DNA encoding viral proteins or OVA generates Ag-specific material that, when presented in vitro by dendritic cells to naive T cells, induces primary CTL response or elicits IL-2 production from an OVA peptide-specific T-T hybridoma. The immunogenic material released was proteinaceous in nature, free of apoptotic bodies, and had an apparent m.w. much larger than a 9–11-aa CTL-recognizable peptide. The macrophage-released factor(s) specifically required a hydrolyzable ATP substrate and was inhibited by procedures that removed or hydrolyzed ATP; in addition, anti-heat-shock protein 70 antiserum abrogated the activity to a large extent. These results indicate the possible involvement of a heat-shock protein 70-linked peptide chaperone in a cross-priming method of immune induction by DNA vaccination. Such a cross-priming process may represent a principal mechanism by which plasmid DNA delivered to cells such as myocytes effectively shuttle Ag to DC or other APC to achieve CTL induction in vivo.
Facing Two T Cell Epitopes: A Degree of Randomness in the Primary Response Is Lost Upon Secondary Immunization
Authors: Bousso Philippe , Lemaı̂tre Fabrice , Bilsborough Janine , Kourilsky Philippe 
Published: April 2014

AbstractWe have analyzed the hierarchy of epitope-specific T cell populations during a primary and a secondary CD8 T cell response. MHC-peptide tetramers were used to track the in vivo kinetics of expansion of T cell populations specific for two Kd-restricted epitopes simultaneously presented by a murine tumor cell following primary or recall immunizations. Individual syngeneic mice generated remarkably different primary CTL responses, as reflected by up to 60-fold differences in the relative contribution of each peptide-specific T cell population to the overall response. In these primary immunizations, the CTL dominance was not dictated by the respective abundance of the presented epitopes. In sharp contrast, the secondary response was systematically associated with a selective expansion of the same epitope-specific population both in vitro and in vivo. In vitro experiments indicated that the extent of expansion of each epitope-specific memory population is modulated by the epitope density. We conclude that, at least for this set of epitopes, the CTL hierarchy is not controlled by the same parameters in a primary vs a secondary response.
Gr-1+ Myeloid Cells Derived from Tumor-Bearing Mice Inhibit Primary T Cell Activation Induced Through CD3/CD28 Costimulation
Authors: Kusmartsev Sergei A. , Li Yu , Chen Shu-Hsia 
Published: April 2014

AbstractActivation of T cells is a necessary step in the development of a specific antitumor immune response. In the present study, we evaluated the ability of Gr-1+ myeloid cells, derived from the bone marrow or spleen of tumor-bearing mice, to inhibit CD3/CD28-mediated T cell activation. Using flow cytometry, we found that growth of a murine colon carcinoma (MCA-26) induces a significant increase in the number of Gr-1+ and Gr-1+/Mac-1+ myeloid cells in both bone marrow and spleen of the tumor host. The proliferative response of T cells was dramatically decreased when naive T cells were activated by anti-CD3 and anti-CD28 Abs in the presence of a myeloid-enriched cell fraction derived from spleen or bone marrow of tumor-bearing mice vs the bone marrow of naive mice. Reversal of the inhibitory effect could be achieved by adding a combination of MnTBAP (manganese [III] tetrakis [4-benzoic acid]) porphyrin and l-NMMA (NG-monomethyl-l-arginine), a superoxide dismutase mimetic and inducible NO synthase inhibitor, respectively, or by depletion of the Gr-1-positive cells. IFN-γ, which is endogenously produced by CD3/CD28-stimulated naive T cells, is involved in induction of the inhibitory activity of myeloid cells. Importantly, when T cells pre-activated with anti-CD3 Abs were used as responder cells, the bone marrow- or spleen-derived Gr-1+ myeloid cells were unable to suppress CD3/CD28-induced T cell proliferation. Our findings suggest that one mechanism by which an increased number of immune suppressive Gr-1+ cells can induce T cell unresponsiveness or immune tolerance in tumor hosts could be through peroxynitrite production upon primary T cell activation.
Phenotypic and Functional Characterization of Mouse Hepatic CD8α+ Lymphoid-Related Dendritic Cells
Authors: O’Connell Peta J. , Morelli Adrian E. , Logar Alison J. , Thomson Angus W. 
Published: April 2014

AbstractRecently, attention has focussed on phenotypic and functional differences between classic myeloid dendritic cells (DC), and DC that reportedly develop from an early, committed lymphoid precursor. In mice, DC from these separate hemopoietic lineages differ by their surface expression of CD8α. We undertook a comparative study of CD8α+ (CD11blow; lymphoid-related) and CD8α− (CD11bhigh; myeloid) DC isolated from mouse liver. CD8α+ and CD8α− DC each constituted ≤1.0% of the freshly isolated, normal nonparenchymal cells (NPC). Both populations were enriched 10–15% by overnight culture and metrizamide density centrifugation. Flt3 ligand (Flt3L) potently induced equal expansion of both subsets in vivo. Tissue-resident CD8α+ DC, freshly isolated from Flt3L-treated mice, existed primarily as immature cells (CD11c+, CD11blow, CD40−/low, CD80low, CD86low, MHC class IIlow), consistent with previous observations regarding bulk DC freshly isolated from nonlymphoid tissues. Following overnight culture in GM-CSF, CD8α+ DC underwent phenotypic and functional maturation equivalent to that observed for CD8α− DC. CD95 ligand (FasL) mRNA was detected in both immature and mature DC of each subset. In vitro analysis confirmed that flow-sorted, mature CD8α+ and CD8α− DC were strong and equally efficient stimulators of allogeneic T cell proliferation in primary MLR. Both immunohistochemical and genomic DNA analysis revealed that in vivo, sorted CD8α+ DC trafficked from s.c. sites to T cell areas of allogeneic lymphoid tissue and were equally efficient at priming naive T cells compared with CD8α− DC. This is the first comparative study of lymphoid-related DC isolated from nonlymphoid tissue.
Abnormal Immune Function of Hemopoietic Cells from Alymphoplasia (aly) Mice, a Natural Strain with Mutant NF-κB-Inducing Kinase
Authors: Yamada Takuji , Mitani Tasuku , Yorita Kazuko , Uchida Daisuke , Matsushima Akemi , Iwamasa Kikue , Fujita Shigeru , Matsumoto Mitsuru 
Published: April 2014

AbstractAlymphoplasia (aly) mice, a natural strain with a mutant NF-κB-inducing kinase (NIK) gene, manifest a unique phenotype; they lack lymph nodes and Peyer’s patches, have a disturbed spleen architecture, and exhibit defects in both Ab and cellular immune responses. Although a stromal defect caused by impaired lymphotoxin-β receptor signaling accounts for their abnormal lymphoid organogenesis, the exact mechanisms underlying the development of immunodeficiency in aly mice are poorly understood. We therefore investigated the contribution of hemopoietic cells with the aly NIK mutation to the development of immunodeficiency. Transfer of aly/aly bone marrow cells into aly/+ mice resulted in poorly developed B cell follicles and lack of support for the development of germinal centers and isotype switching, indicating that the hemopoietic cells of aly mice contain an autonomous defect. However, follicular dendritic cell clusters were maintained in the spleens of these bone marrow chimeras, suggesting that the lack of follicular dendritic cell clusters in aly mice is probably due to the stromal defect. The aly mice lacked marginal zone B cells in their spleens, and aly/aly B cells showed an impaired proliferative response after in vitro stimulation. IL-2 production by activated T cells was also impaired. By contrast, the dendritic cells of aly mice exhibited grossly normal development and function. Supporting the concept of an autonomous cell defect, Rel protein expression was altered in aly/aly spleens. Thus, the aly NIK mutation affects hemopoietic cell function in an intrinsic fashion and, together with the stromal defect, may contribute to the development of immunodeficiency in aly mice.
Molecular Basis for Nonanaphylactogenicity of a Monoclonal Anti-IgE Antibody
Authors: Rudolf Michael P. , Zuercher Adrian W. , Nechansky Andreas , Ruf Christine , Vogel Monique , Miescher Sylvia M. , Stadler Beda M. , Kricek Franz 
Published: April 2014

AbstractIgE Abs mediate allergic responses by binding to specific high affinity receptors (FcεRI) on mast cells and basophils. Therefore, the IgE/FcεRI interaction is a target for clinical intervention in allergic disease. An anti-IgE mAb, termed BSW17, is nonanaphylactogenic, although recognizing IgE bound to FcεRI, and interferes with binding of IgE to FcεRI. Thus, BSW17 represents a candidate Ab for treatment of IgE-mediated disorders. By panning BSW17 against random peptide libraries displayed on phages, we defined mimotopes that mimic the conformational epitope recognized on human IgE. Two types of mimotopes, one within the Cε3 and one within the Cε4 domain, were identified, indicating that this mAb may recognize either a large conformational epitope or eventually two distinct epitopes on IgE. On the basis of alignments of the two mimotopes with the human IgE sequence, we postulate that binding of BSW17 to the Cε3 region predominantly blocks binding of IgE to FcεRI, leading to neutralization of IgE. Moreover, binding of BSW17 to the Cε4 region may explain how BSW17 recognizes FcεRI-bound IgE, and binding to this region may also interfere with degranulation of IgE sensitized cells (basophils and mast cells). As a practical application of these findings, mimotope peptides coupled to a carrier protein may be used for the development of a peptide-based anti–allergy vaccine by induction of anti-IgE Abs similar to the current approach of using humanized nonanaphylactogenic anti-IgE Abs as a passive vaccine.
CD164 Monoclonal Antibodies That Block Hemopoietic Progenitor Cell Adhesion and Proliferation Interact with the First Mucin Domain of the CD164 Receptor
Authors: Doyonnas Regis , Yi-Hsin Chan James , Butler Lisa H. , Rappold Irene , Lee-Prudhoe Jane E. , Zannettino Andrew C. W. , Simmons Paul J. , Bühring Hans-Jörg , Levesque Jean-Pierre , Watt Suzanne M. 
Published: April 2014

AbstractThe novel sialomucin, CD164, functions as both an adhesion receptor on human CD34+ cell subsets in bone marrow and as a potent negative regulator of CD34+ hemopoietic progenitor cell proliferation. These diverse effects are mediated by at least two functional epitopes defined by the mAbs, 103B2/9E10 and 105A5. We report here the precise epitope mapping of these mAbs together with that of two other CD164 mAbs, N6B6 and 67D2. Using newly defined CD164 splice variants and a set of soluble recombinant chimeric proteins encoded by exons 1–6 of the CD164 gene, we demonstrate that the 105A5 and 103B2/9E10 functional epitopes map to distinct glycosylated regions within the first mucin domain of CD164. The N6B6 and 67D2 mAbs, in contrast, recognize closely associated and complex epitopes that rely on the conformational integrity of the CD164 molecule and encompass the cysteine-rich regions encoded by exons 2 and 3. On the basis of their sensitivities to reducing agents and to sialidase, O-sialoglycoprotease, and N-glycanase treatments, we have characterized CD164 epitopes and grouped them into three classes by analogy with CD34 epitope classification. The class I 105A5 epitope is sialidase, O-glycosidase, and O-sialoglycoprotease sensitive; the class II 103B2/9E10 epitope is N-glycanase, O-glycosidase, and O-sialoglycoprotease sensitive; and the class III N6B6 and 67D2 epitopes are not removed by such enzyme treatments. Collectively, this study indicates that the previously observed differential expression of CD164 epitopes in adult tissues is linked with cell type specific post-translational modifications and suggests a role for epitope-associated carbohydrate structures in CD164 function.
Expression of Toll-Like Receptor 2 on γδ T Cells Bearing Invariant Vγ6/Vδ1 Induced byEscherichia coliInfection in Mice
Authors: Mokuno Yasuji , Matsuguchi Tetsuya , Takano Manabu , Nishimura Hitoshi , Washizu Junji , Ogawa Tomohiko , Takeuchi Osamu , Akira Shizuo , Nimura Yuji , Yoshikai Yasunobu 
Published: April 2014

AbstractWe recently reported that the number of γδ T cells was increased after infection with Escherichia coli in C3H/HeN mice. We here showed that an i.p. injection with native lipid A derived from E. coli induced an increase of γδ T cells in the peritoneal cavity of LPS-responsive C3H/HeN mice and, albeit to a lesser degree, also in LPS-hyporesponsive C3H/HeJ mice. The purified γδ T cells from C3H/HeN and C3H/HeJ mice expressed a canonical TCR repertoire encoded by Vγ6-Jγ1/Vδ1-Dδ2-Jδ2 gene segments and proliferated in response to the native lipid A derived from E. coli in a TCR-independent manner. The lipid A-reactive γδ T cells bearing canonical Vγ6/Vδ1 expressed Toll-like receptor (TLR) 2 mRNA, while TLR4 mRNA was undetectable. Treatment with a TLR2 anti-sense oligonucleotide resulted in hyporesponsiveness of the γδ T cells to the native lipid A. TLR2-deficient mice showed an impaired increase of the γδ T cells following injection of native lipid A. These results suggest that TLR2 is involved in the activation of canonical Vγ6/Vδ1 T cells by native E. coli lipid A.
Central Role of Double-Stranded RNA-Activated Protein Kinase in Microbial Induction of Nitric Oxide Synthase
Authors: Uetani Kohsaku , Der Sandy D. , Zamanian-Daryoush Maryam , de la Motte Carol , Lieberman Belinda Y. , Williams Bryan R. G. , Erzurum Serpil C. 
Published: April 2014

Abstract
NO synthase 2 (NOS2) is induced in airway epithelium by influenza virus infection. NOS2 induction late in the course of viral infection may occur in response to IFN-γ, but early in infection gene expression may be induced by the viral replicative intermediate dsRNA through the dsRNA-activated protein kinase (PKR). Since PKR activates signaling pathways important in NOS2 gene induction, we determined whether PKR is a component in the signal transduction pathway leading to NOS2 gene expression after viral infection of airway epithelium. We show that NOS2 gene expression in human airway epithelial cells occurs in response to influenza A virus or synthetic dsRNA. Furthermore, dsRNA leads to rapid activation of PKR, followed by activation of signaling components including NF-κB and IFN regulatory factor 1. NOS2 expression is markedly diminished and IFN regulatory factor 1 and NF-κB activation are substantially impaired in PKR null cells. Strikingly, NOS2 induction in response to LPS is abolished in PKR null cells, confirming a central role for PKR in the general signaling pathway to NOS2.
Anergic T Cells Inhibit the Antigen-Presenting Function of Dendritic Cells
Authors: Vendetti Silvia , Chai Jian-Guo , Dyson Julian , Simpson Elizabeth , Lombardi Giovanna , Lechler Robert 
Published: April 2014

AbstractThe phenomena of infectious tolerance and linked-suppression are well established, but the mechanisms involved are incompletely defined. Anergic T cells can inhibit responsive T cells in vitro and prolong skin allograft survival in vivo. In this study the mechanisms underlying these events were explored. Allospecific mouse T cell clones rendered unresponsive in vitro inhibited proliferation by responsive T cells specific for the same alloantigens. The inhibition required the presence of APC, in that the response to coimmobilized anti-CD3 and anti-CD28 Abs was not inhibited. Coculture of anergic T cells with bone marrow-derived dendritic cells (DC) led to profound inhibition of the ability of the DC to stimulate T cells with the same or a different specificity. After coculture with anergic T cells expression of MHC class II, CD80 and CD86 by DC were down-regulated. These effects did not appear to be due to a soluble factor in that inhibition was not seen in Transwell experiments, and was not reversed by addition of neutralizing anti-IL-4, anti-IL-10, and anti-TGF-β Abs. Taken together, these data suggest that anergic T cells function as suppressor cells by inhibiting Ag presentation by DC via a cell contact-dependent mechanism.
Lineage-Specific Telomere Shortening and Unaltered Capacity for Telomerase Expression in Human T and B Lymphocytes with Age
Authors: Son Ni Huiping , Murray Shannon , Yanovski Jack , Hodes Richard J. , Weng Nan-ping 
Published: April 2014

AbstractAge effects on telomere length and telomerase expression in peripheral blood lymphocytes were analyzed from 121 normal individuals age newborn to 94 years and revealed several new findings. 1) Telomere shortening was observed in CD4+ and CD8+ T and B cells with age. However, the rate of telomere loss was significantly different in these populations, 35 ± 8, 26 ± 7, and 19 ± 7 bp/year for CD4+ and CD8+ T and B cells, respectively. In addition, CD4+ T cells had the longest average telomeres at all ages, followed by B cells, with CD8+ T cell telomeres the shortest, suggesting that these lymphocyte populations may have different replicative histories in vivo. 2) Telomerase activity in freshly isolated T and B cells was indistinguishably low to undetectable at all ages but was markedly increased after Ag and costimulatory receptors mediated stimulation in vitro. Furthermore, age did not alter the magnitude of telomerase activity induced after stimulation of T or B lymphocytes through Ag and costimulatory receptors or in response to PMA plus ionomycin treatment. 3) The levels of telomerase activity induced by in vitro stimulation varied among individual donors but were highly correlated with the outcome of telomere length change in CD4+ T cells after Ag receptor-mediated activation. Together, these results indicate that rates of age-associated loss of telomere length in vivo in peripheral blood lymphocytes is specific to T and B cell subsets and that age does not significantly alter the capacity for telomerase induction in lymphocytes.