bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upstream NFIL-6-like site located within a DNase I hypersensitivity region mediates LPS-induced transcription of the murine interleukin-1 beta gene.
Authors: Godambe S A , Chaplin D D , Takova T , Bellone C J 
Published: December 2022

Abstract
To define the cis-acting elements that regulate LPS-stimulated IL-1 beta gene transcription, we analyzed the murine IL-1 beta gene by digestion with DNase I. At least two hypersensitive sites were located between 2200 and 2600 bp upstream of the transcription start site in mononuclear phagocytes, but not in an IL-1 nonproducing immature T cell line. Specific DNA sequences required for LPS induction of IL-1 beta gene expression were identified within the DNase I hypersensitive (DH) region using transfection of reporter constructs that contained portions of the IL-1 beta 5'-flanking region. Two specific DNA sequences were targets for nuclear factor binding as assessed with use of electrophoretic mobility shift analysis (EMSA). One site contained a consensus sequence for NFIL-6 binding. Base substitutions within this NFIL-6 site resulted in virtual elimination of LPS-induced IL-1 beta gene transcription. Introduction of multimers of the NFIL-6-like sequence immediately 5' to homologous or heterologous promoters conferred LPS-induced transcription, indicating that this NFIL-6-like consensus site was a transcriptional activator. Anti-C/EBP beta (NFIL-6) and anti-C/EBP delta (NFIL-6 beta) Abs identified both of these proteins in complexes formed between the NFIL-6-like element and mononuclear cell nuclear extracts. C/EBP delta (NFIL-6 beta) was not detected in complexes utilizing extracts from the IL-1 nonproducing T cell line. These data are consistent with the requirement for C/EBP beta (NFIL-6) and C/EBP delta (NFIL-6 beta) in the activation of murine IL-1 beta gene expression by endotoxin.
IL-10-induced factors belonging to the p91 family of proteins bind to IFN-gamma-responsive promoter elements.
Authors: Lehmann J , Seegert D , Strehlow I , Schindler C , Lohmann-Matthes M L , Decker T 
Published: December 2022

Abstract
Expression of the gene encoding the high affinity IgG receptor (Fc gamma RI) is stimulated by IFN-gamma through a promoter element designated gamma-IFN activation site (GAS). This sequence binds a transcription factor designated gamma-IFN activation factor (GAF). GAF-GAS complexes contain an IFN-regulated 91-kDa protein (p91). In mouse peritoneal macrophages, IL-4 and IL-10 influenced both basal and IFN-gamma-induced expression of Fc gamma RI in opposite ways: IL-10 was stimulatory and IL-4 repressed Fc gamma RI expression. IL-4 or IL-10 did not affect the activation of GAF by IFN-gamma, but both activated the binding of latent, receptor-activated factors (RAFTs) to the Fc gamma RI GAS. RAFTs-IL-4 and -IL-10 migrated similarly in electrophoretic mobility shift assays but could be distinguished through their specificities for different GAS sequences and their reactivity with anti-p91 antisera. These experiments also revealed two distinct RAFTs-IL-10 to be members of the p91 family of proteins. The data suggest GAS-related elements to integrate signals from IFN-gamma-, IL-4- and IL-10-activated signaling paths.
Analysis of binding of monoclonal antibody to a malarial peptide by surface plasmon resonance biosensor and integrated rate equations.
Authors: Wohlhueter R M , Parekh K , Udhayakumar V , Fang S , Lal A A 
Published: December 2022

Abstract
Using biosensor technology and integrated rate equations, we have developed procedures to determine the kinetic parameters and equilibrium affinity constant of Ag-Ab interactions. The Ag used in these studies was a peptide that represents the major B cell epitope of the circumsporozoite protein of Plasmodium falciparum, a promising malaria vaccine candidate Ag. Measurements of association and dissociation rate constants of this peptide with the mAb 2A10 were determined by fitting integrated rate equations to binding data obtained with a BIAcore surface plasmon-resonance biosensor. We examined whether accurate estimates of initial velocity and final equilibrium levels of binding of Ab to peptides can be obtained using these methods, and whether kinetic rates and equilibrium constants obtained with systematic variation of the experimental parameters conform to a simple bimolecular model of binding. We found that initial velocity was approximately first order with respect to Ab concentration. When we used a series of four sensor cells with different peptides loads, however, we found that the initial velocity of binding appeared to be nearly independent of peptide concentration. Equilibrium analyses yielded dissociation constants of approximately 3 x 10(-7) M. Integrated rate treatment of biosensor data supports a critical examination of the assumptions on which the binding models are based and suggests a need to refine such models. Nevertheless, it provides a powerful quantitative tool for assessing the Ag-Ab binding reaction.
Origin and steady-state turnover of class II MHC-bearing dendritic cells in the epithelium of the conducting airways.
Authors: Holt P G , Haining S , Nelson D J , Sedgwick J D 
Published: December 2022

Abstract
Recent studies have identified a contiguous network of class II MHC-bearing dendritic cells (DC) in the airway epithelium of several species, including humans. This network seems comparable to the epidermal Langerhans cell population, comprising up to 700 DC per mm2 of airway epithelium. Moreover, it accounts for virtually all local immunostaining for class II MHC, suggesting an important role in surveillance for inhaled Ag. This study examines the turnover of these airway DC using a radiation chimera model that uses congenic rats expressing different allotypic variants of CD45, detectable via mAbs. Steady-state bone marrow renewal of the airway DC population (which is continuously depleted by migration of mature cells to draining lymph nodes) was interrupted via x-irradiation or high-dose dexamethasone, after which the resident population declined by 85% over the ensuing 72 h. After transplantation with congenic bone marrow and an initial lag period for graft establishment, the airway DC population was rapidly restored to preirradiation levels. These findings indicate a half-life of &lt; or = 2 days for airway epithelial DC. In contrast, epidermal Langerhans cell half-life was &gt; or = 15 days. The only comparable (short) half-life previously reported for a peripheral tissue DC population, is that derived from the gut wall. This indicates that rapidly turning over DC populations are a unique feature of the major "mucosal" organ systems, which is consistent with these DC playing an important role in surveillance of mucosal tissues for incoming Ag.
Peripheral blood mononuclear cells stimulated with C5a or lipopolysaccharide to synthesize equivalent levels of IL-1 beta mRNA show unequal IL-1 beta protein accumulation but similar polyribosome profiles.
Authors: Kaspar R L , Gehrke L 
Published: December 2022

Abstract
Recent reports suggest that regulation of IL-1 beta gene expression in human monocytes may include translation level as well as transcription level control mechanisms. We studied IL-1 beta expression in PBMC stimulated with recombinant complement protein C5a or with LPS. IL-1 beta mRNA was expressed by C5a-treated PBMC, but very little or no IL-1 beta protein could be detected by ELISA or by Western blot analysis using a polyclonal Ab that reacts equally with pro-IL-1 beta and processed mature IL-1 beta. LPS-treated cells produced both IL-1 beta mRNA and protein. Velocity sedimentation analysis revealed, however, that IL-1 beta mRNA assembles into large polyribosomes in both C5a- and LPS-treated cells. Translation of the IL-1 beta mRNA in C5a-treated cells is not therefore blocked at the level of protein synthesis initiation. IL-1 beta mRNA was released from polyribosomes by treating the cells with puromycin, suggesting that the ribosomes are not frozen at the elongation phase of protein synthesis. One explanation for the data is that the rate of IL-1 beta polypeptide chain elongation or termination may be diminished in the C5a-stimulated PBMC.
Discordant adaptation of human peritoneal macrophages to stimulation by lipopolysaccharide and the synthetic lipid A analogue SDZ MRL 953. Down-regulation of TNF-alpha and IL-6 is paralleled by an up-regulation of IL-1 beta and granulocyte colony-stimulating factor expression.
Authors: Knopf H P , Otto F , Engelhardt R , Freudenberg M A , Galanos C , Herrmann F , Schumann R R 
Published: December 2022

Abstract
Human peritoneal macrophages were exposed to increasing doses of LPS or a synthetic lipid A analogue (SDZ MRL 953) and production of the cytokines IL-1 beta, IL-6, TNF-alpha, and G-CSF was assessed at the protein and mRNA level. Cells were also prestimulated with low doses of LPS and SDZ MRL 953 to study their adaptation to a secondary challenge with high doses of LPS. The ability of macrophages to produce high levels of TNF-alpha and IL-6 after stimulation with LPS could be relieved almost completely by preincubating cells with low doses of LPS. Decreases of TNF-alpha and IL-6 production resulted from inhibition of gene transcription and/or changes in mRNA stability, as transcript levels of these cytokines were down-modulated by the process of LPS adaptation. Surprisingly, however, adapted cells were able to synthesize even larger quantities of G-CSF and IL-1 beta when exposed to a secondary LPS challenge. mRNA levels of the adapted cells remained unaltered for IL-1 beta, but were slightly increased for G-CSF as assessed by Northern blot analysis. High doses of the synthetic lipid A analogue SDZ MRL 953 were also able to adapt macrophages to a secondary LPS challenge by down-regulating TNF-alpha and IL-6 production, whereas priming secretion of G-CSF and IL-1 beta as well. We describe here the discordant adaptation of human peritoneal macrophages to a secondary LPS stimulus in vitro. These findings appear to have ramifications for the in vivo endotoxin response during inflammation and also Gram-negative septicemia.
Gender differences in IL-1 alpha, IL-1 beta, and IL-1 receptor antagonist secretion from mononuclear cells and urinary excretion.
Authors: Lynch E A , Dinarello C A , Cannon J G 
Published: December 2022

Abstract
Previous studies have reported increased secretion of IL-1-like activity from mononuclear cells and increased circulating levels during the luteal phase of the menstrual cycle. In this investigation, specific RIAs for the agonists IL-1 alpha and IL-beta as well as IL-1 receptor antagonist (IL-1Ra) were used to determine whether differential IL-1 secretory patterns exist between men and women or between phases of the menstrual cycle. Mononuclear cells were isolated from six men and five women at 4-h intervals from 8 am to 8 pm, with the women studied once in midfollicular phase and once in midluteal phase. In the absence of any intentional stimulation, significant differences in secretion were observed between groups (p &lt; 0.03) for all three species of IL-1: women's cells isolated during the luteal phase secreted 5- to 10-fold more than cells from men, and women's cells isolated during the follicular phase secreted 13- to 28-fold more than cells from men. In addition, total 24-h urine samples were collected in intervals with end points coinciding with the blood samples. Urinary excretion correlated with cellular secretion for IL-beta and IL-1Ra (p = 0.024 and 0.028, respectively), indicating that the in vitro results may correspond to differential processes occurring in vivo. Although greater absolute amounts of each species of IL-1 were secreted during the follicular phase, the ratio of agonist to antagonist secreted was greater in the luteal phase (p &lt; 0.05), in agreement with previous studies of bioactivity. These results indicate that the regulation of IL-1 secretion is fundamentally different in women compared with men and alludes to the possibility that IL-1 may serve different biologic functions in women than men.
CR2 is the primary acceptor site for C3 during alternative pathway activation of complement on human peripheral B lymphocytes.
Authors: Marquart H V , Svehag S E , Leslie R G 
Published: December 2022

Abstract
Human cells infected with certain viruses acquire the ability to activate the alternative pathway (AP) of complement. Complement receptor 2 on EBV-infected lymphoblastoid cell lines has been reported to act as the covalent binding site for C3b during AP activation. Using flow cytometry, we investigated the ability of normal human peripheral blood leukocytes to activate the AP in homologous serum. Deposition of C3 fragments was determined as a measurement of complement activation on each of the subpopulations of the blood cells. Incubating human peripheral blood leukocytes with homologous or autologous serum resulted in C3 deposition on B cells and, to a lesser extent, on monocytes and polymorphonuclear leukocytes. Complement activation in the presence of Mg2+ ions and EGTA revealed major involvement of the AP in the case of B cells, and to a lesser extent for other leukocyte populations examined. Preincubation of the leukocytes with polyclonal anti-complement receptor 2 Ab markedly decreased the C3 fragment deposition, as a result of in vitro AP activation, on B cells, indicating that on normal human B cells this receptor may be involved in AP activation. Freshly isolated, normal human B cells also bear low but significant amounts of C3d,g fragments on their membranes, indicating that this AP activation also occurs in vivo. AP activation was partially decreased in the presence of autologous erythrocytes (RBC) suggesting that complement regulatory proteins on RBC play a role in limiting the AP activation in vivo.
Antigen receptor-mediated transmembrane signaling in Wiskott-Aldrich syndrome.
Authors: Henriquez N V , Rijkers G T , Zegers B J 
Published: December 2022

Abstract
The X-linked immunodeficiency Wiskott-Aldrich syndrome (WAS) is a condition that includes a deficient anti-polysaccharide Ab response. Recently, it has been suggested that B cells from patients with WAS show a defective calcium mobilization response upon engagement of sIgM. Because primarily EBV-transformed cells were used in these studies, we tested freshly isolated blood B cells for their calcium mobilization capability upon engagement of sIg and CD19. No significant differences in the calcium mobilization capability of CD20+ B cells of four individual WAS patients compared with capability in normal controls were found. Receptor desensitization as assessed by calcium mobilization inhibition also seemed to be intact. T cells were tested for their anti-CD3-induced calcium flux and, again, no abnormalities could be observed when compared with T cells from healthy individuals. We conclude that WAS B and T cells can be stimulated into a normal calcium mobilization response when their AgRs are cross-linked. It is highly improbable that the immune dysfunction observed in WAS patients is related to a direct disorder of their B and/or T cell AgRs.
Characterization of peripheral autoregulatory mechanisms that prevent development of cyclosporin-induced syngeneic graft-versus-host disease.
Authors: Hess A D , Fischer A C , Horwitz L , Bright E C , Laulis M K 
Published: December 2022

Abstract
Administration of cyclosporin after syngeneic bone marrow transplantation paradoxically elicits a T lymphocyte-dependent autoaggression syndrome termed syngeneic graft-vs-host disease (SGVHD). The induction of SGVHD requires two essential components, the emergence of autoreactive lymphocytes from the thymus and the elimination of a T cell-dependent peripheral autoregulatory mechanism. These studies used the SGVHD model to further characterize this regulatory system that modifies the autoimmune potential of autoreactive effector cells. Our studies reveal that although cyclosporin did not interfere with the effector function of the autoregulatory T cells, it prevented the reconstitution of the regulatory system after syngeneic bone marrow transplantation. Furthermore, the autoregulation of SGVHD is a dynamic process specifically recognizing and responding to the autoreactive SGVHD effector cells. Challenge or priming of normal Lewis rats by intravenous infusion of irradiated SGVHD effector cells activates and amplifies this autoregulatory system resulting in: 1) a threefold enhancement of autoregulatory T cell function, 2) the appearance of a dominant autoregulatory T cell population belonging to the CD4+ T helper lymphocyte subset, and 3) the capacity of irradiated primed autoregulatory T cells to inactivate SGVHD effector lymphocytes in vitro. Additional studies reveal that effective autoregulation required a specific interaction of the TCR-alpha/beta on the autoregulatory cells with the MHC class II determinants on the autoreactive lymphocytes.
Dissociation rate of antibody-gp120 binding interactions is predictive of V3-mediated neutralization of HIV-1.
Authors: VanCott T C , Bethke F R , Polonis V R , Gorny M K , Zolla-Pazner S , Redfield R R , Birx D L 
Published: December 2022

Abstract
mAbs specific for the V3 loop of HIV-1 are capable of neutralizing laboratory strains of HIV-1 in vitro. In this report we use surface plasmon resonance and biosensor technology to demonstrate that the ability of V3-specific mAbs to neutralize HIV-1(MN) correlated with the dissociation rate constant of the homologous mAb-gp120 binding interaction. mAbs capable of binding diverse strains of gp120 with similar association rate constants exhibited marked differences in the dissociation rate. The dissociation rate, and not the association rate, was found to be predictive of the neutralization capacity of the mAb. Furthermore, synthetic peptides corresponding to the V3 loop of HIV-1(IIIB, MN) yielded quantitatively similar binding kinetic profiles abrogating the need for purified recombinant gp120 protein and potentially facilitating the screening of more diverse isolates. Biosensor immobilized V3 peptides were found to mimic their conformational structure in solution. This offers advantages to peptides studied by ELISA where some degree of denaturation and masking of epitopes can occur upon adsorption of peptides to plastic surfaces. The impact of amino acid substitutions within epitopes on subsequent mAb binding was dissected by observing alterations in dissociation rates. The technique provides rapid kinetic analyses of V3 Ab binding interactions with diverse V3 sequences, facilitating the efficient screening and selection of those most likely to possess the broadest and most potent HIV-1 neutralizing potentials.
Identification of epitopes of myelin oligodendrocyte glycoprotein for the induction of experimental allergic encephalomyelitis in SJL and Biozzi AB/H mice.
Authors: Amor S , Groome N , Linington C , Morris M M , Dornmair K , Gardinier M V , Matthieu J M , Baker D 
Published: December 2022

Abstract
A recombinant protein corresponding to the Ig-like domain of myelin oligodendrocyte glycoprotein (MOG) and synthetic 15-mer peptides of the whole MOG molecule with eight amino acid overlaps were screened for their ability to induce experimental allergic encephalomyelitis (EAE) in Biozzi AB/H (H-2dq1) and SJL (H-2S) mice. Clinical and histologic evidence of EAE developed after sensitization with the recombinant MOG protein in both AB/H and SJL mice. In AB/H mice at least three MOG epitopes within residues 1-22, 43-57, and 134-148 induced clinical and histologic EAE, whereas only the sequence 92-106 was encephalitogenic in SJL mice. Histologically, the inflammatory response in the central nervous system consisted of perivascular accumulations of CD5+ T cells and F4/80+ macrophage/microglia cells equally distributed in the brain and spinal cord. The subpial/meningeal infiltration, characteristic of mouse EAE induced with spinal cord homogenate, was only observed in cases of severe clinical disease in SJL mice in which the cellular infiltrates predominated in the spinal cord. In spite of the presence of histologic lesions in AB/H mice immunized with MOG, clinical disease either rapidly resolved or was clinically silent. In contrast to immunization of SJL mice with recombinant MOG, sensitization to MOG 92-106 induced severe clinical paralysis. After recovery these animals relapsed and exhibited demyelinated lesions. This study is the first to describe encephalitogenic epitopes of MOG that induce both clinical and histologic signs of EAE in mice. These and previous findings implicating MOG as a target Ag for Ab-mediated attack in EAE suggest that such autoreactivity to MOG may be significant in the development of human demyelinating diseases such as multiple sclerosis.
Characterization of a 70-kDa, EBV gp350/220-binding protein on HSB-2 T cells.
Authors: Hedrick J A , Lao Z , Lipps S G , Wang Y , Todd S C , Lambris J D , Tsoukas C D 
Published: December 2022

Abstract
EBV binds and infects HSB-2 T cells via a receptor distinct from CD21. To further study this novel EBV receptor, we expressed the first 470 amino acids of the EBV-gp350/220 using the baculovirus expression system. The recombinant gp350/220(1-470) has a m.w. of 95 kDa, reacts with anti-gp350/220 Abs, and binds CD21 in ELISA. Radiolabeled gp350/220(1-470) binds both HSB-2 and Raji cells. The gp350/220(1-470) protein also inhibits EBV binding to both HSB-2 and Raji, detected by flow cytometry. Lysates of HSB-2 cells compete with CD21 for binding to gp350/220(1-470), suggesting that the two receptors bind related epitopes on the recombinant protein. Scatchard analysis reveals that gp350/220(1-470) binds to 34,000 high affinity sites/HSB-2 cell (Kd = 0.92 x 10(-8) M) compared with the 97,000 high affinity sites bound/Raji cell (Kd = 1.78 x 10(-8) M). Utilizing a gp350/220(1-470)-affinity matrix, we identify a 70-kDa (55-kDa nonreduced) protein on the surfaces of 125I-labeled HSB-2 cells. Binding of this protein to the matrix is inhibited by anti-gp350/220 Ab 72A1. In summary, we characterize a novel EBV-binding molecule on HSB-2 cells, compare its reactivity with gp350/220 to that of CD21, and provide evidence of a gp350/220-reactive, 70-kDa protein on the surfaces of HSB-2 cells. In view of previous evidence of HSB-2 infectivity by EBV, we propose that the 70 kDa protein represents the novel EBV receptor.