bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitogenic Activity of Purified Capsular Polysaccharide A from Bacteroides fragilis: Differential Stimulatory Effect on Mouse and Rat Lymphocytes In Vitro
Authors: Brubaker Jeffery O. , Li Qiao , Tzianabos Arthur O. , Kasper Dennis L. , Finberg Robert W. 
Published: January 2023

Abstract
Bacteroides fragilis, a Gram-negative colonic bacterium, induces the formation of abscesses associated with intra-abdominal sepsis in humans. The singular ability of this organism to modulate abscess formation in experimental rodent models resides in the structurally distinct and ionically charged capsular polysaccharides A (PS A) and B (PS B). The regulation of abscess formation in animals is dependent on T lymphocytes. However, the manner in which PS A interacts with T cells remains unknown. We therefore tested the T cell stimulatory capacity of purified PS A on mouse and rat lymphocytes in cellular proliferation assays and found that the PS A molecule possesses mitogenic characteristics distinguishable from those of the polyclonal B cell activator LPS, the T cell mitogen Con A, and staphylococcal enterotoxin A superantigen. Further, PS A stimulated proliferation of normal mouse and rat lymphocytes differentially. Mouse B cells responded to PS A in a fashion that did not require exogenous APC function, while rat T lymphocyte responses to PS A required APC function derived from autologous or xenogenic feeder cells. Cellular depletion experiments showed that the CD4+ subset of rat spleen cells was the primary responder cell type to PS A in vitro. The differential stimulatory effects of PS A on mouse and rat lymphocytes may reflect its ability to stimulate different lymphocyte subsets in vivo through the activities of receptor/counter-receptor pairs present on responder lymphocytes and cognate APC.
Bacterial Superantigens Induce Down-Modulation of CC Chemokine Responsiveness in Human Monocytes Via an Alternative Chemokine Ligand-Independent Mechanism
Authors: Rahimpour Rahbar , Mitchell Gordon , Khandaker Masud H. , Kong Chen , Singh Bhagirath , Xu Luoling , Ochi Atsuo , Feldman Ross D. , Pickering J. Geoffrey , Gill Bruce M. , Kelvin David J. 
Published: January 2023

AbstractStaphylococcal superantigens (SAgs) are very potent T cell mitogens, but they can also activate monocytes by binding directly to MHC class II molecules in a manner independent of TCR coengagement. Induction of proinflammatory cytokines and chemokine expression in monocytes by superantigens has recently been reported. Here we report that superantigen stimulation of human peripheral blood monocytes results in a rapid, dose-dependent, and specific down-regulation of chemokine (macrophage inflammatory protein-1α (MIP-1α), monocyte chemotactic protein-1 and MIP-1β) binding sites (e.g., CCR1, CCR2, and CCR5), which correlates with a concomitant hyporesponsiveness of human monocytes to these CC chemokine ligands. This down-regulation occurs 15–30 min following superantigen stimulation and is specific to chemokine receptors, in that binding and responsiveness of monocytes to the chemoattractant formyl-tripeptide FMLP are not affected. We further demonstrate that SAg-induced down-modulation of chemokine binding and monocyte hyporesponsiveness to the chemokines MIP-1α, monocyte chemotactic protein-1, and MIP-1β is mediated through cellular protein tyrosine kinases, and the down-modulation can be mimicked by an MHC class II-specific mAb. Additionally, our observations indicate that SAg-induced loss of chemokine binding and monocyte responsiveness is probably mediated by secreted serine proteinases. Bacterial SAg-induced down-modulation of chemokine responsiveness represents a previously unrecognized strategy by some bacteria to subvert immune responses by affecting the intricate balance between chemokine and chemokine receptor expression and function.
Vasoactive Intestinal Peptide and Pituitary Adenylate Cyclase-Activating Polypeptide Inhibit Endotoxin-Induced TNF-α Production by Macrophages: In Vitro and In Vivo Studies
Authors: Delgado Mario , Pozo David , Martinez Carmen , Leceta Javier , Calvo Juan Ramon , Ganea Doina , Gomariz Rosa P. 
Published: January 2023

AbstractVasoactive intestinal peptide (VIP) is a neuropeptide synthesized by immune cells that can modulate several immune aspects, including the function of cells involved in the inflammatory response, such as macrophages and monocytes. The production and release of cytokines by activated phagocytes are important events in the pathogenesis of ischemia-reperfusion injury. There is abundant evidence that the proinflammatory cytokine TNF-α is an important mediator of shock and organ failure complicating Gram-negative sepsis. VIP has been shown to attenuate the deleterious consequences of this pathologic phenomenon. In this study we have investigated the effects of VIP and the structurally related neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP38) on the production of TNF-α by endotoxin-activated murine peritoneal macrophages. Both neuropeptides rapidly and specifically inhibit the LPS-stimulated production of TNF-α, exerting their action through the binding to VPAC1 receptor and the subsequent activation of the adenylate cyclase system. VIP and PACAP regulate the production of TNF-α at a transcriptional level. In vitro results were correlated with an inhibition of both TNF-α expression and release in endotoxemic mice in vivo. The immunomodulatory role of VIP in vivo is supported by the up-regulation of VIP release in serum and peritoneal fluid by LPS and proinflammatory cytokines such as TNF-α, IL-1β, and IL-6. These findings support the idea that under toxicity conditions associated with high LPS doses, VIP and PACAP could act as protective mediators that regulate the excessive release of TNF-α to reduce inflammation or shock.
Immunostimulatory CpG-Oligodeoxynucleotides Cause Extramedullary Murine Hemopoiesis
Authors: Sparwasser Tim , Hültner Lothar , Koch Eva Sophie , Luz Arne , Lipford Grayson B. , Wagner Hermann 
Published: January 2023

AbstractBacterial DNA and the synthetic CpG-oligodeoxynucleotides (ODNs) derived thereof have attracted attention because they activate cells of the adaptive immune system (lymphocytes) and the innate immune system (APCs) in a sequence-dependent manner. Here, we addressed whether CpG-ODNs affect hemopoiesis. Challenging mice with immunostimulatory CpG-ODN sequences led to transient splenomegaly, with a maximum increase of spleen weight at day 6. The induction of splenomegaly by CpG-ODNs was sequence-specific, dose-dependent, and associated with an increase in splenic cell count, in numbers of granulocyte-macrophage CFUs (GM-CFUs), and early erythroid progenitors (burst-forming units-erythroid). The transfer of spleen cells from CpG-ODN-pretreated animals into lethally irradiated syngeneic mice yielded an increase of spleen CFUs. Furthermore, the challenge of sublethally irradiated mice with CpG-ODNs caused radioprotective effects, in that recovery of GM-CFUs and cytotoxic T cell function was enhanced. The increase in GM-CFU and CTL function correlated with an enhanced resistance to Listeria infection in irradiated mice. We conclude from these data that CpG-ODNs trigger extramedullary hemopoiesis, and that this finding could be of therapeutic relevance in myelosuppression.
A Conformation-Dependent Epitope in Addison’s Disease and Other Endocrinological Autoimmune Diseases Maps to a Carboxyl-Terminal Functional Domain of Human Steroid 21-Hydroxylase
Authors: Nikoshkov Andrej , Falorni Alberto , Lajic Svetlana , Laureti Stefano , Wedell Anna , Lernmark Åke , Luthman Holger 
Published: January 2023

Abstract
Idiopathic Addison’s disease develops as a consequence of autoimmune destruction of steroid-producing cells in the adrenal gland. A major autoantigen is 21-hydroxylase (21OH; P450c21), which is involved in the biosynthesis of cortisol and aldosterone in the adrenal cortex. We selected a number of functionally important 21OH amino acid substitutions, found in patients with congenital adrenal hyperplasia, to study their effects on the binding of 21OH autoantibodies (21OHAb) to 21OH. The ability of 21OHAb to bind in vitro transcribed and translated wild-type 21OH and five different 21OH mutant proteins was quantified by liquid-phase assays. Sera from 21OHAb-positive patients with idiopathic Addison’s disease (n = 24), Graves’ disease (n = 3), and insulin-dependent diabetes mellitus (n = 1) were used. While the P105L, delE196, and G291S mutations had no effect on autoantibody binding, the P453S mutation had a considerable effect, and the R483P mutation almost completely abolished binding. Synthetic peptides corresponding to linear epitopes defined by amino acids 447–461 and 477–491 were unable to compete with wild-type 21OH for binding to autoantibodies. Direct 21OH DNA sequencing could not reveal any specific genetic variation in alleles found in 21OHAb-positive patients. We conclude that the region involving R483 plays a key role in the formation of a three-dimensional epitope in a functionally important C-terminal domain of the enzyme.
Cutting Edge: Negative Selection of Immature Thymocytes by a Few Peptide-MHC Complexes: Differential Sensitivity of Immature and Mature T Cells
Authors: Peterson Daniel A. , DiPaolo Richard J. , Kanagawa Osami , Unanue Emil R. 
Published: January 2023

AbstractWe quantitated the number of peptide-class II MHC complexes required to affect the deletion or activation of 3A9 TCR transgenic thymocytes. Deletion of immature double positive thymocytes was very sensitive, taking place with approximately three peptide-MHC complexes per APC. However, the activation of mature CD4+ thymocytes required 100-fold more complexes per APC. Therefore, a “biochemical margin of safety” exists at the level of the APC. To be activated, autoreactive T cells in peripheral lymphoid tissues require a relatively high level of peptide-MHC complexes.
Tetracycline Up-Regulates COX-2 Expression and Prostaglandin E2 Production Independent of Its Effect on Nitric Oxide
Authors: Attur Mukundan G. , Patel Rajesh N. , Patel Prakash D. , Abramson Steven B. , Amin Ashok R. 
Published: January 2023

AbstractTetracyclines (doxycycline and minocycline) augmented (one- to twofold) the PGE2 production in human osteoarthritis-affected cartilage (in the presence or absence of cytokines and endotoxin) in ex vivo conditions. Similarly, bovine chondrocytes stimulated with LPS showed (one- to fivefold) an increase in PGE2 accumulation in the presence of doxycycline. This effect was observed at drug concentrations that did not affect nitric oxide (NO) production. In murine macrophages (RAW 264.7) stimulated with LPS, tetracyclines inhibited NO release and increased PGE2 production. Tetracycline(s) and l-N-monomethylarginine (l-NMMA) (NO synthase inhibitor) showed an additive effect on inhibition of NO and PGE2 accumulation, thereby uncoupling the effects of tetracyclines on NO and PGE2 production. The enhancement of PGE2 production in RAW 264.7 cells by tetracyclines was accompanied by the accumulation of both cyclooxygenase (COX)-2 mRNA and cytosolic COX-2 protein. In contrast to tetracyclines, l-NMMA at low concentrations (≤100 μM) inhibited the spontaneous release of NO in osteoarthritis-affected explants and LPS-stimulated macrophages but had no significant effect on the PGE2 production. At higher concentrations, l-NMMA (500 μM) inhibited NO release but augmented PGE2 production. This study indicates a novel mechanism of action of tetracyclines to augment the expression of COX-2 and PGE2 production, an effect that is independent of endogenous concentration of NO.
Early Membrane Rupture Events During Neutrophil-Mediated Antibody-Dependent Tumor Cell Cytolysis
Authors: Kindzelskii Andrei L. , Petty Howard R. 
Published: January 2023

Abstract
Although cell-mediated cytolysis is a fundamental immune effector response, its mechanism remains poorly understood at the cellular level. In this report, we image for the first time transient ruptures, as inferred by cytoplasmic marker release, in tumor cell membranes during Ab-dependent cellular cytolysis. The cytosol of IgG-opsonized YAC tumor cells was labeled with tetramethylrhodamine diacetate followed by the formation of tumor cell-neutrophil conjugates. We hypothesized that tumor cell cytolysis proceeds via a series of discrete membrane rupture/resealing events that contribute to marker release. To test this hypothesis, we occluded the fluorescence image of the labeled tumor cells by passing an opaque disk into a field-conjugated plane between the light source and the sample. Multiple small bursts of fluorescent label release from tumor cells could be detected using a photomultiplier tube. Similarly, multiple fluorescent plumes were observed at various sites around the perimeter of a target. These findings support a multihit model of target cytolysis and suggest that cytolytic release is not focused at specific sites. Cytolytic bursts were generally observed at 20-s intervals, which match the previously described reduced nicotinamide-adenine dinucleotide phosphate and superoxide release oscillation periods for neutrophils; we speculate that metabolic oscillations of the effector cell drive the membrane damage of the target.
IL-2-Dependent Expression of Genes Involved in Cytoskeleton Organization, Oncogene Regulation, and Transcriptional Control
Authors: Herblot Sabine , Chastagner Patricia , Samady Laila , Moreau Jean-Louis , Demaison Christophe , Froussard Patrick , Liu Xinyuan , Bonnet Jacques , Thèze Jacques 
Published: January 2023

AbstractIL-2 induces growth, differentiation, and/or apoptosis of lymphoid cells. To study further the molecular basis of IL-2 function, we used a cDNA subtraction approach involving a cell line grown in IL-2 or IL-4. From the corresponding library, 66 nonredundant sequences were characterized; 16 of them encode identified proteins. The kinetics of in vitro expression of 8 selected sequences, the functions of which could be associated with IL-2-induced T cell activation/differentiation, was investigated using an IL-2-dependent T cell line. IL-2 increased the expression of cytoskeleton proteins (α-tubulin), oncogene-regulating proteins (CCCTC-binding factor, Jun inhibitor factor-1), and transcription factors (E2F-4, cyclic AMP-responsive element-binding protein, zhx-1). IL-2 also regulated the expression of genes coding for multifunctional proteins, e.g., β-catenin and nucleolin. These results were verified using Con A-induced T cell blasts stimulated or not by IL-2. The in vivo expression of four of these genes was also analyzed in spleen and lymph node cells of IL-2-deficient and MRL/lpr mice, which both have high numbers of activated cells, but the latter have intact IL-2 expression. The expression of β-catenin, CCCTC-binding factor, Jun inhibitor factor-1, and nucleolin was significantly higher in MRL/lpr animals. A similar analysis of thymocytes from IL-2−/− and IL-2+/− mice demonstrated the same expression patterns of the 4 sequences in these strains. The expression of the IL-2-induced genes described herein is similar to the regulatory pattern of IL-2Rα. Taken together, our data provide additional evidence for the pleiotropic action of IL-2 in the periphery and IL-2 independence of molecular processes involved in thymocyte differentiation.
Enumeration of Antigen-Presenting Cells in Mice Infected with Sendai Virus
Authors: Usherwood Edward J. , Hogg Twala L. , Woodland David L. 
Published: January 2023

AbstractSubstantial progress has been made in understanding Ag presentation to T cells; however, relatively little is known about the location and frequency of cells presenting viral Ags during a viral infection. Here, we took advantage of a highly sensitive system using lacZ-inducible T cell hybridomas to enumerate APCs during the course of respiratory Sendai virus infection in mice. Using lacZ-inducible T cell hybridomas specific for the immunodominant hemagglutinin-neuraminidase HN421–436/I-Ab and nucleoprotein NP324–332/Kb epitopes, we detected APCs in draining mediastinal lymph nodes (MLNs), in cervical lymph nodes, and also in the spleen. HN421–436/I-Ab- and NP324–332/Kb-presenting cells were readily detectable between days 3 and 9 postinfection, with more APCs present in the MLN than in the cervical lymph nodes. Interestingly, no infectious virus was detected in lymphoid tissue beyond day 6, suggesting that a depot of noninfectious viral Ag survives, in some form, for 2–3 days after viral clearance. Fractionation of the MLN demonstrated that APC frequency was enriched in dendritic cells and macrophages but depleted in the B cell population, suggesting that B cells do not form a large population of APCs during the primary response to this virus.
CD86 (B7-2) Can Function to Drive MHC-Restricted Antigen-Specific CTL Responses In Vivo
Authors: Agadjanyan Michael G. , Kim Jong J. , Trivedi Neil , Wilson Darren M. , Monzavi-Karbassi Behjatolah , Morrison Lake D. , Nottingham Liesl K. , Dentchev Tzvete , Tsai Anthony , Dang Kesen , Chalian Ara A. , Maldonado Michael A. , Williams William V. , Weiner David B. 
Published: January 2023

AbstractActivation of T cells requires both TCR-specific ligation by direct contact with peptide Ag-MHC complexes and coligation of the B7 family of ligands through CD28/CTLA-4 on the T cell surface. We recently reported that coadministration of CD86 cDNA along with DNA encoding HIV-1 Ags i.m. dramatically increased Ag-specific CTL responses. We investigated whether the bone marrow-derived professional APCs or muscle cells were responsible for the enhancement of CTL responses following CD86 coadministration. Accordingly, we analyzed CTL induction in bone marrow chimeras. These chimeras are capable of generating functional viral-specific CTLs against vaccinia virus and therefore represent a useful model system to study APC/T cell function in vivo. In vaccinated chimeras, we observed that only CD86 + Ag + MHC class I results in 1) detectable CTLs following in vitro restimulation, 2) detectable direct CTLs, 3) enhanced IFN-γ production in an Ag-specific manner, and 4) dramatic tissue invasion of T cells. These results support that CD86 plays a central role in CTL induction in vivo, enabling non-bone marrow-derived cells to prime CTLs, a property previously associated solely with bone marrow-derived APCs.
Structural Deficiencies in Granuloma Formation in TNF Gene-Targeted Mice Underlie the Heightened Susceptibility to Aerosol Mycobacterium tuberculosis Infection, Which Is Not Compensated for by Lymphotoxin
Authors: Bean Andrew G. D. , Roach Daniel R. , Briscoe Helen , France Malcolm P. , Korner Heinrich , Sedgwick Jonathon D. , Britton Warwick J. 
Published: January 2023

Abstract
TNF and lymphotoxin-α (LTα) may act at various stages of the host response to Mycobacterium tuberculosis. To dissect the effects of TNF independent of LTα, we have used C57BL/6 mice with a disruption of the TNF gene alone (TNF−/−). Twenty-one days following aerosol M. tuberculosis infection there was a marked increase in the number of organisms in the lungs of TNF−/− mice, and by 28–35 days all animals had succumbed, with widespread dissemination of M. tuberculosis. In comparison with the localized granulomas containing activated macrophages and T cells in lungs and livers of C57BL/6 wild-type (wt) mice, cellular infiltrates in TNF−/− mice were poorly formed, with extensive regions of necrosis and neutrophilic infiltration of the alveoli. Phenotypic analysis of lung homogenates demonstrated similar numbers of CD4+ and CD8+ T cells in TNF−/− and wt mice, but in TNF-deficient mice the lymphocytes were restricted to perivascular and peribronchial areas rather than colocated with macrophages in granulomas. T cells from TNF−/− mice retained proliferative and cytokine responses to purified protein derivative, and delayed-type hypersensitivity to purified protein derivative was demonstrable. Macrophages within the lungs of TNF−/− and wt mice showed similar levels of MHC class II and inducible nitric oxide synthase expression, and levels of serum nitrite were comparable. Thus, the enhanced susceptibility of TNF−/− is not compensated for by the presence of LTα, and the critical role of TNF is not in the activation of T cells and macrophages but in the local organization of granulomas.
Successful Adoptive Immunotherapy of MurinePoorly ImmunogenicTumor with Specific Effector Cells Generated from Gene-Modified Tumor-Primed Lymph Node Cells
Authors: Tanaka Hiroshi , Yoshizawa Hirohisa , Yamaguchi Yoshifumi , Ito Kazuhisa , Kagamu Hiroshi , Suzuki Eiichi , Gejyo Fumitake , Hamada Hirofumi , Arakawa Masaaki 
Published: January 2023

AbstractWe previously reported that cytokine gene transfer into weakly immunogenic tumor cells could enhance the generation of precursor cells of tumor-reactive T cells and subsequently augment antitumor efficacy of adoptive immunotherapy. We investigated whether such potent antitumor effector T cells could be generated from mice bearing poorly immunogenic tumors. In contrast to similarly modified weakly immunogenic tumors, MCA102 cells, which are chemically induced poorly immunogenic fibrosarcoma cells transfected with cDNA for IL-2, IL-4, IL-6, IFN-γ, failed to augment the host immune reaction. Because priming of antitumor effector T cells in vivo requires two important signals provided by tumor-associated Ags and costimulatory molecules, these tumor cells were cotransfected with a B7-1 cDNA. Transfection of both IFN-γ and B7-1 (MCA102/B7-1/IFN-γ) resulted in regression of s.c. tumors, while tumor transfected with other combinations of cytokine and B7-1 showed progressive growth. Cotransfection of IFN-γ and B7-1 into other poorly immunogenic tumor B16 and LLC cells also resulted in the regression of s.c. tumors. Cells derived from lymph nodes draining MCA102/B7-1/IFN-γ tumors showed potent antitumor efficacy, eradicating established pulmonary metastases, but this effect was not seen with parental tumors. This mechanism of enhanced antitumor efficacy was further investigated, and T cells with down-regulated L-selectin expression, which constituted all the in vivo antitumor reactivity, were significantly increased in lymph nodes draining MCA102/B7-1/IFN-γ tumors. These T cells developed into potent antitumor effector cells after in vitro activation with anti-CD3/IL-2. The strategy presented here may provide a basis for developing potent immunotherapy for human cancers.
Soluble Fas Ligand Is Chemotactic for Human Neutrophilic Polymorphonuclear Leukocytes
Authors: Ottonello Luciano , Tortolina Giuseppe , Amelotti Massimo , Dallegri Franco 
Published: January 2023

Abstract
It has been recently shown that Fas ligand (FasL) expression on islet β grafts results in neutrophilic infiltration and graft rejection. In this study, we show that human recombinant soluble FasL is endowed with potent chemotactic properties toward human neutrophilic polymorphonuclear leukocytes (neutrophils) at concentrations incapable of inducing cell apoptosis. Furthermore, neutrophils exposed to soluble FasL did not display detectable change of intracellular Ca2+ and did not undergo superoxide production or exocytosis of primary and secondary granules. Our results show that FasL is a potent chemoattractant for human neutrophils without evoking their secretory responses. This finding suggests a novel proinflammatory function for this ligand and may help to clarify the mechanism governing FasL-mediated graft rejection, thereby offering rational bases for controlling and modulating FasL-based immunotherapies.