bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutting Edge: Role of Macrophage Migration Inhibitory Factor in Inhibiting NK Cell Activity and Preserving Immune Privilege
Authors: Apte R. S. , Sinha D. , Mayhew E. , Wistow G. J. , Niederkorn J. Y. 
Published: January 2023

Abstract
The absence of MHC class I Ags on the corneal endothelium, which lines the anterior chamber of the eye, makes this cell layer potentially vulnerable to lysis by NK cells. However, aqueous humor (AH), which bathes the corneal endothelium, contains a 12-kDa protein which inhibits the NK-mediated lysis of corneal endothelial cells. An amino acid sequence analysis of AH revealed that this factor shared &gt;90% homology with macrophage migration inhibitory factor (MIF). The NK inhibitory effect of AH was neutralized with anti-human MIF Ab. Moreover, mouse rMIF produced a similar inhibition of NK cell activity. However, neither rMIF nor AH inhibited the CTL-mediated lysis of allogeneic cells. rMIF prevented the release of perforin granules by NK cells but not CTLs. Although MIF displays proinflammatory properties, these results indicate that it can also inhibit at least one immune effector element, NK cells, and thereby contribute to immune privilege in the eye.
Inefficient Assembly and Intracellular Accumulation of Antibodies with Mutations in VH CDR2
Authors: Martin Tammy M. , Wiens Gregory D. , Rittenberg Marvin B. 
Published: January 2023

AbstractWe previously described secretion defects in four mutants of the murine anti-phosphocholine Ab, T15. The mutant heavy (H) chains had amino acid replacements in the VH complementarity-determining region 2 (HCDR2) and were expressed at normal intracellular levels. Here, the intracellular fate of the secretion-defective mutant heavy chains was investigated. Metabolic labeling demonstrated that the T15 wild-type Ab was secreted within a 4-h chase. In contrast, the mutant H chains accumulated with intracellular t1/2 values ranging from 10 to 24 h. The mutant H chains were associated with increased levels of the molecular chaperones BiP and GRP94, and remained endoglycosidase H sensitive, suggesting retention in the endoplasmic reticulum. Assembly of the mutant H chains with T15 light (L) chain was arrested at the H2 and H2L intermediate stages of the T15 wild-type pathway (H2 → H2L → H2L2). Even though some assembly with L chain occurred, it was not as a secretion-competent H2L2 Ig moiety. The T15 L chains coexpressed with mutant H chains were degraded efficiently except for a minor L chain population with a long t1/2 that was apparently protected at the H2L stage. To our knowledge, this is the first study demonstrating that intracellular half-lives of Ig H and L chains can be influenced by somatic mutations in HCDR2.
The α2 Domain of H-2Dd Restricts the Allelic Specificity of the Murine NK Cell Inhibitory Receptor Ly-49A
Authors: Sundbäck Jonas , Nakamura Mary C. , Waldenström Margareta , Niemi Eréne C. , Seaman William E. , Ryan James C. , Kärre Klas 
Published: January 2023

AbstractMouse NK lymphocytes express Ly-49 receptors, which inhibit cytotoxicity upon ligation by specific MHC I molecules on targets. Different members of the lectin-like mouse Ly-49 receptor family recognize distinct subsets of murine H-2 molecules, but the molecular basis for the allelic specificity of Ly-49 has not been defined. We analyzed inhibition of natural killing by chimeric MHC I molecules in which the α1, α2, or α3 domains of the Ly-49A-binding allele H-2Dd were exchanged for the corresponding domains of the nonbinding allele H-2Db. Using the Ly-49A-transfected rat NK cell line, RNK-mLy-49A.9, we demonstrated that the H-2Dd α2 domain alone accounts for allelic specificity in protection of rat YB2/0 targets in vitro. We also showed that the H-2Dd α2 domain is sufficient to account for the allele-specific in vivo protection of H-2b mouse RBL-5 tumors from NK cell-mediated rejection in D8 mice. Thus, in striking contrast to the α1 specificity of Ig-like killer inhibitory receptors for human HLA, the lectin-like mouse Ly-49A receptor is predominantly restricted by the H-2Dd α2 domain in vitro and in vivo.
Suppression of Immune Responses by CD8 Cells. I. Superantigen-Activated CD8 Cells Induce Unidirectional Fas-Mediated Apoptosis of Antigen-Activated CD4 Cells
Authors: Noble Alistair , Pestano Gary A. , Cantor Harvey 
Published: January 2023

Abstract
Stimulation of mature CD4 cells through the TCR induces cellular activation and expansion that are often followed by clonal elimination by a form of apoptosis3 termed activation-induced cell death. This process of CD4 cell apoptosis is generally thought to reflect clonal suicide and to be independent of other cell types. Here we show that during the response to the superantigen Staphylococcal enterotoxin A, activated CD8 cells, but not activated CD4 cells, suppress the CD4 proliferative response. Suppression by CD8 cells reflects their ability to induce CD4 cell apoptosis via ligation of Fas. Moreover, although activated CD8 cells that express Fas ligand and Fas eliminate CD4 cells through a Fas-dependent mechanism, they are themselves resistant to Fas-dependent apoptosis. These findings indicate a fundamental difference between the two major T cell subsets with regard to sensitivity to Fas-dependent apoptosis, expression of Fas ligand, and mediation of suppressive activity following immunization with superantigen.
Blockade of Chemokine Activity by a Soluble Chemokine Binding Protein from Vaccinia Virus
Authors: Alcamí Antonio , Symons Julian A. , Collins Paul D. , Williams Timothy J. , Smith Geoffrey L. 
Published: January 2023

AbstractChemokines direct migration of immune cells into sites of inflammation and infection. Chemokine receptors are seven-transmembrane domain proteins that, in contrast to other cytokine receptors, cannot be easily engineered as soluble chemokine inhibitors. Poxviruses encode several soluble cytokine receptors to evade immune surveillance, providing new strategies for immune modulation. Here we show that vaccinia virus and other orthopoxviruses (cowpox and camelpox) express a secreted 35-kDa chemokine binding protein (vCKBP) with no sequence similarity to known cellular chemokine receptors. The vCKBP binds CC, but not CXC or C, chemokines with high affinity (Kd = 0.1–15 nM for different CC chemokines), blocks the interaction of chemokines with cellular receptors, and inhibits chemokine-induced elevation of intracellular calcium levels and cell migration in vitro, thus representing a soluble inhibitor that binds and sequesters chemokines. The potential of vCKBP as a therapeutic agent in vivo was illustrated in a guinea pig skin model by the blockade of eotaxin-induced eosinophil infiltration, a feature of allergic inflammatory reactions. Furthermore, vCKBP may enable the rational design of antagonists to neutralize pathogens that use chemokine receptors to initiate infection, such as HIV or the malarial parasite.
NK Cells from Human MHC Class I (HLA-B) Transgenic Mice Do Not Mediate Hybrid Resistance Killing Against Parental Nontransgenic cells
Authors: Kung Sam K. P. , Su Ruey-Chyi , Graham Jeremy J. K. , Chamberlain John W. , Miller Richard G. 
Published: January 2023

Abstract
We have investigated the capacity of human MHC class I HLA-B gene products, HLA-B27, -B7 (fully human), and -B7Kb (human-mouse hybrid consisting of the α1 and α2 domains of HLA-B7, and the α3 and cytoplasmic domains of mouse H-2Kb), expressed on mouse NK cells during ontogeny to influence NK recognition of otherwise syngeneic mouse target cells. Despite a high level of surface expression of the transgene (comparable to that of endogeneous H-2DbKb molecules), the direct killing of YAC-1 targets, and the killing of P815 targets in a redirected lysis assay, the NK effectors of these transgenic mice could not mediate hybrid resistance-like killing of nontransgenic C57BL/6 target cells either in vitro or in vivo. Splenocytes from B6-B27 mice could be used to generate CTL lines against a B27-binding peptide, implying that T cells restricted by HLA-B27 developed during ontogeny. NK cells from B6-B27 could lyse B6-B27 Con A lymphoblasts pulsed with Db-binding peptide but not B27-binding peptides. Taken together, our results show that these human HLA-B transgene products cannot function as class I MHC “self” elements for mouse NK cells, even when present throughout ontogeny.
Nuclear Targeted Suppression of NF-κB Activity by the Novel Quinone Derivative E3330
Authors: Hiramoto Masaki , Shimizu Noriaki , Sugimoto Kotaro , Tang Jianwei , Kawakami Yutaka , Ito Masaharu , Aizawa Shin , Tanaka Hirotoshi , Makino Isao , Handa Hiroshi 
Published: January 2023

Abstract
The activation of NF-κB consists of at least three steps: degradation of IκBα, translocation of NF-κB into the nucleus, and post-translational modification of NF-κB (e.g., phosphorylation of p65). In the present study, we found that a novel quinone derivative E3330 selectively inhibited NF-κB-mediated gene expression without affecting any of these steps. E3330, when included in the culture medium, suppressed NF-κB DNA-binding activity in PMA-induced Jurkat cell nuclear extracts, suggesting that the inhibition by E3330 of NF-κB-mediated gene expression was due to its ability to suppress NF-κB DNA-binding activity. Fractionation of the nuclear extracts by column chromatography revealed that a nuclear factor enhanced NF-κB DNA-binding activity and that this enhancing activity was interrupted after treatment with E3330. Moreover, a major polypeptide with a molecular mass of 40 kDa was found to be in the highly purified fraction containing the NF-κB-enhancing activity and predominantly bind E3330. Taken together, these results suggest that the NF-κB activity, after dissociation from IκB, is enhanced by a nuclear factor that is active irrespective of PMA treatment, and the nuclear factor-mediated enhancement is selectively inhibited by E3330. Thus, we conclude that E3330 may belong to a novel class of anti-NF-κB drugs.
Neuropeptides, Via Specific Receptors, Regulate T Cell Adhesion to Fibronectin
Authors: Levite Mia , Cahalon Liora , Hershkoviz Rami , Steinman Lawrence , Lider Ofer 
Published: January 2023

Abstract
The ability of T cells to adhere to and interact with components of the blood vessel walls and the extracellular matrix is essential for their extravasation and migration into inflamed sites. We have found that the β1 integrin-mediated adhesion of resting human T cells to fibronectin, a major glycoprotein component of the extracellular matrix, is induced by physiologic concentrations of three neuropeptides: calcitonin gene-related protein (CGRP), neuropeptide Y, and somatostatin; each acts via its own specific receptor on the T cell membrane. In contrast, substance P (SP), which coexists with CGRP in the majority of peripheral endings of sensory nerves, including those innervating the lymphoid organs, blocks T cell adhesion to fibronectin when induced by CGRP, neuropeptide Y, somatostatin, macrophage inflammatory protein-1β, and PMA. Inhibition of T cell adhesion was obtained both by the intact SP peptide and by its 1–4 N-terminal and its 4–11, 5–11, and 6–11 C-terminal fragments, used at similar nanomolar concentrations. The inhibitory effects of the parent SP peptide and its fragments were abrogated by an SP NK-1 receptor antagonist, suggesting they all act through the same SP NK-1 receptor. These findings suggest that neuropeptides, by activating their specific T cell-expressed receptors, can provide the T cells with both positive (proadhesive) and negative (antiadhesive) signals and thereby regulate their function. Thus, neuropeptides may influence diverse physiologic processes involving integrins, including leukocyte-mediated migration and inflammation.
Generation of an Inhibitory Circuit Involving CD8+ T Cells, IL-2, and NK Cell-Derived TGF-β: Contrasting Effects of Anti-CD2 and Anti-CD3
Authors: Gray J. Dixon , Hirokawa Makoto , Ohtsuka Kazuo , Horwitz David A. 
Published: January 2023

AbstractAlthough the phenomenon of immunosuppression is well established, the mechanisms involved in the generation of lymphocytes with down-regulatory activity are poorly understood. Unlike anti-CD3 antibodies, mitogenic combinations of anti-CD2 antibodies do not stimulate human PBL to produce IgM or IgG. In determining the reason for this difference, we have found that anti-CD2 triggers an inhibitory circuit facilitated by TGF-β provided by NK cells. Stimulation of PBL with anti-CD2, but not anti-CD3, generated substantial amounts of active TGF-β. NK cells were found to be a significant source of TGF-β and were the only lymphocyte population that constitutively produced this cytokine. Anti-CD2 enhanced the production of active TGF-β by purified NK cells. TGF-β. After the removal of NK cells or the addition of anti-TGF-β, anti-CD2 could stimulate Ig production. Anti-TGF-β had to be added within the first 24 h for a maximal effect. Moreover, a short, overnight exposure of CD8+ T cells to TGF-β could prime them for suppressor activity provided that IL-2 was also present. Thus, the presence of active TGF-β coincident with CD8+ T cell activation can condition these cells to mediate down-regulatory activity, and NK cells can serve as the source of this cytokine.
Decreased Production of TGF-β by Lymphocytes from Patients with Systemic Lupus Erythematosus
Authors: Ohtsuka Kazuo , Gray J. Dixon , Stimmler Mary M. , Toro Bricia , Horwitz David A. 
Published: January 2023

AbstractTGF-β has marked inhibitory effects on the immune system but also serves as a costimulatory factor in the development of T cells with down-regulatory activities. This cytokine is secreted as a latent complex and converted extracellularly to its active form. We have recently learned that anti-CD2 is a potent inducer of lymphocyte-derived TGF-β and that NK cells are the predominant source. The objective of this study was to compare levels of constitutive, anti-CD2-induced and cytokine-regulated TGF-β produced by blood lymphocytes from patients with systemic lupus erythematosus (SLE) in comparison with healthy controls. Using a highly sensitive and specific bioassay to assess TGF-β, we report that unstimulated PBL from SLE patients, especially the NK cell subset, produced decreased levels of active TGF-β. In response to anti-CD2, concentrations of active and total TGF-β were also decreased in SLE. After learning that IL-2 and TNF-α enhance lymphocyte production of active TGF-β, we found that the addition of these cytokines was unable to increase active TGF-β to normal concentrations. Although we observed that IL-10 inhibited the production of active TGF-β, antagonism of this cytokine was unable to completely correct the defect. In two SLE patients with B cell hyperactivity, spontaneous IgG production was almost abolished by the combination of TGF-β and IL-2. Therefore, decreased production of each of these cytokines in SLE could be important in the perpetuation of B cell hyperactivity.
The Actin-Bundling Protein Fascin Is Involved in the Formation of Dendritic Processes in Maturing Epidermal Langerhans Cells
Authors: Ross Ralf , Ross Xiao-Lan , Schwing Jens , Längin Tina , Reske-Kunz Angelika B. 
Published: January 2023

AbstractDendritic cells (DC) are characterized by their unique potential to prime naive T cells. Epidermal Langerhans cells (LC), the DC resident in the epidermis, gain this immunostimulatory capacity following Ag contact in vivo or during in vitro culture of epidermal cell suspensions. To analyze differential gene expression in maturing LC, we constructed a highly representative cDNA library of cultivated LC (cLC) in λ ZAP II containing 18 × 106 independent clones. This library was screened with freshly isolated Langerhans cell (fLC)- and cLC-derived probes for cLC-specific cDNAs. The cDNAs identified were sequenced and analyzed by database searches. Two cDNA fragments were identified as fragments of fascin, indicating that fascin is differentially expressed in LC. By competitive RT-PCR, we confirmed that fascin is highly expressed in cLC cultivated for 1, 2, and 3 days, while no signals were obtained with fLC. Western blot and immunofluorescence analysis revealed cLC-specific expression of fascin on the protein level as well. Fascin is known to be involved in the organization of the actin cytoskeleton in cytoplasmatic extensions of nerve growth cones. Its differential expression in maturing LC coincides with the formation of numerous dendritic projections in LC. Their formation was inhibited by incubation of LC with fascin antisense oligonucleotides during cultivation. Therefore, we conclude that fascin is necessary for the formation of the dendritic processes of maturing Langerhans cells and may thus influence T cell-LC interaction.
Thymic Alterations Induced by 2,3,7,8-Tetrachlorodibenzo-p-Dioxin Are Strictly Dependent on Aryl Hydrocarbon Receptor Activation in Hemopoietic Cells
Authors: Staples J. Erin , Murante Francis G. , Fiore Nancy C. , Gasiewicz Thomas A. , Silverstone Allen E. 
Published: January 2023

Abstract2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related congeners affect the immune system, causing immunosuppression and thymic atrophy in a variety of animal species. TCDD is believed to exert its effects primarily through the ligand-activated transcription factor, the aryl hydrocarbon receptor (AhR). Although the AhR is found at high levels in both thymocytes and thymic stroma, it is uncertain in which cells TCDD is activating the AhR to cause alterations in the thymus. Some investigators have suggested that stromal elements, primarily epithelial cells, within the thymus are the primary targets for TCDD. Others have suggested that atrophy is due to a direct effect on thymocytes, either by apoptosis or by altering the development of progenitor cells. By producing chimeric mice with TCDD-responsive (AhR+/+) stromal components and TCDD-unresponsive (AhR−/−) hemopoietic components, or the reverse, we have clarified the role of stromal vs hemopoietic elements in TCDD-induced thymic alterations. Our results show that the targets for TCDD-induced thymic atrophy and phenotypic alterations are strictly in the hemopoietic compartment and that TCDD activation of epithelial cells in the stroma is not required for thymic alterations. Furthermore, changes observed in the putative stem cell populations of these chimeric mice are also dependent on TCDD activation of the AhR in hemopoietic elements.
Extracellular HIV-1 Tat Protein Induces the Rapid Ser133 Phosphorylation and Activation of CREB Transcription Factor in Both Jurkat Lymphoblastoid T Cells and Primary Peripheral Blood Mononuclear Cells
Authors: Gibellini Davide , Bassini Alessandra , Pierpaoli Sabina , Bertolaso Lucia , Milani Daniela , Capitani Silvano , La Placa Michele , Zauli Giorgio 
Published: January 2023

Abstract
Extracellular HIV-1 Tat protein (0.1–100 ng/ml) induced a rapid (peak at 30 min) increase in the Ser133 phosphorylation levels of the transcription factor CREB in serum-starved Jurkat cells, as revealed by Western blot and indirect immunofluorescence analyses. Nuclear cAMP-responsive element (CRE) binding activity in electrophoretic mobility shift assays was constitutive in unstimulated Jurkat cells, showing only a small increase upon Tat treatment. However, transient transfection experiments performed with various chloramphenicol acetyl-transferase (CAT) constructs showed that Tat produced a fourfold induction of CAT activity only in the presence of a CRE-dependent CAT construct. Moreover, the use of plasmids encoding for GAL4-CREB fusion proteins demonstrated that Tat induction of pG4-CAT reporter gene required the CREB moiety of the GAL4-CREB fusion protein and that Ser133 CREB was essential for Tat activity. Extracellular Tat also stimulated Ser133 CREB phosphorylation in freshly isolated PBMC; this effect was completely blocked by either staurosporin, a broad-spectrum inhibitor of various protein kinases, or PD 98059, a specific inhibitor of mitogen-activated protein kinases (MAPK). Furthermore, extracellular Tat induced a rapid (peak at 5–15 min) stimulation of the MAPK catalytic activity in primary PBMC. Altogether, these findings suggest that HIV-1 Tat protein activates CREB in lymphoid cells through a signal cascade involving the MAPK pathway.
An Antagonistic IL-4 Mutant Prevents Type I Allergy in the Mouse: Inhibition of the IL-4/IL-13 Receptor System Completely Abrogates Humoral Immune Response to Allergen and Development of Allergic Symptoms In Vivo
Authors: Grunewald Susanne M. , Werthmann Antje , Schnarr Bernd , Klein C. Eberhard , Bröcker Eva B. , Mohrs Markus , Brombacher Frank , Sebald Walter , Duschl Albert 
Published: January 2023

Abstract
We have analyzed in vivo effects of the murine IL-4 mutant Q116D/Y119D (QY), which forms unproductive complexes with IL-4Rα and is an antagonist for IL-4 and IL-13 in vitro. Treatment of BALB/c mice with QY during immunization with OVA completely inhibited synthesis of OVA-specific IgE and IgG1. BALB/c-derived knockout mice lacking either IL-4 or IL-4Rα also did not develop specific IgE or IgG1, but mounted a much stronger IgG2a and IgG2b response than wild-type mice. In contrast, QY treatment of normal BALB/c mice suppressed specific IgG2a, IgG2b, and IgG3 synthesis, which may indicate the development of tolerance toward the allergen. Associated with the lack of IgE synthesis in QY-treated wild-type mice and in IL-4−/− mice used as a control was the failure to develop immediate cutaneous hypersensitivity or anaphylactic shock upon rechallenge. Interestingly, QY treatment also inhibited humoral immune responses and allergic reactivity in SJL/J mice, a strain that did not produce IgE, but displayed IgE-independent mast cell degranulation mediated by specific IgG1. We conclude that QY inhibits Ag-specific humoral immune responses and allergic symptoms mediated either by IgE or IgG1. It needs to be clarified how QY abrogates synthesis of IgG2a, IgG2b, and IgG3, but the induction of tolerance toward nonhazardous protein Ags should be advantageous for therapy of atopic disorders and other Th2-dominated diseases.
Only Selected Light Chains Combine with a Given Heavy Chain to Confer Specificity for a Model Glycopeptide Antigen
Authors: Czerwinski Marcin , Siemaszko Dorota , Siegel Don L. , Spitalnik Steven L. 
Published: January 2023

AbstractThe M and N human blood group glycopeptide Ags are carried on RBCs by glycophorin A. Previous results suggested that the murine humoral immune response against the N, but not the M, Ag is restricted. In addition, these results suggested that particular highly homologous heavy chains might be able to combine promiscuously with various light chains to yield anti-N specificity. To examine this, the current study used Fab phage methodology to couple an array of light chains, obtained from cDNA libraries isolated from immunized mice, to single Fd obtained from N61, N92, and 425/2B hybridomas. Interestingly, for the chimeric Fab to retain M or N specificity, the new light chains needed to belong to the same Vk gene family as the light chain from the parental, hybridoma-derived mAb. In some cases the new light chains modified the Fab affinity and fine specificity. For example, library-derived light chains coupled with the N92 Fd yielded chimeric Fab with increased affinity. In particular, the affinity of these univalent chimeric Fab for the N Ag was equivalent to that of the bivalent parental IgG mAb. Taken together, these results demonstrate that particular structures formed by the light chain V region are required to cooperate with a particular heavy chain V region to create a functional binding site for these glycopeptide Ags. They also demonstrate a lack of heavy chain promiscuity in the formation of murine anti-M and anti-N Abs.