bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epitopic analysis by anti-I-Ak monoclonal antibodies of I-Ak-restricted presentation of lysozyme peptides.
Authors: Rosloniec E F , Gay D , Freed J H 
Published: December 2022

Abstract
Anti-I-A mAb were used as probes of functional epitopes for both the presentation of hen egg lysozyme (HEL) peptides to I-Ak-restricted T cell hybridomas and the direct binding of the HEL (46-61) peptide. When mAb directed to polymorphic regions of I-Ak were used as inhibitors of Ag presentation, several different patterns of inhibition were observed among T cells specific for the same HEL peptide as well as among T cells specific for different fragments of HEL. Although there appears to be a conserved usage of some TCR V beta gene segments among the T cell hybrids specific for the same HEL peptide, no correlation is evident between a single V gene usage and susceptibility to blocking of Ag presentation by a particular anti-I-Ak mAb. Several of the mAb demonstrated T cell "clonotypic blocking" of Ag presentation, whereas others blocked presentation to every T cell hybrid tested, regardless of the peptide specificity. When mAb directed to nonpolymorphic regions of the I-A molecule were tested for their ability to block Ag presentation, little or no inhibition was observed. In addition, Fab' fragments of inhibitory mAb functioned identically to their intact homologous counterparts in their ability to block Ag presentation indicating that "nonspecific" steric hindrance was not playing a major role in the inhibitions observed. When the polymorphic region-directed anti-I-A mAb were tested for their ability to block the direct binding of the lysozyme peptide HEL(46-61) to I-Ak, those mAb that block HEL presentation to all T cell hybrids were found to block the binding of this peptide. However, anti-I-A mAb that demonstrate selective inhibition of T cell hybrid stimulation during Ag presentation, i.e., those directed to polymorphic serologic specificities Ia.15 and Ia.19, do not block the binding of HEL(46-61) to I-Ak. These data indicate that functionally independent epitopes exist on the I-Ak molecule for the binding of antigenic peptides and for interaction with the TCR.
Cyclosporin A is an adjuvant in murine IgE antibody responses.
Authors: Chen S S , Stanescu G , Magalski A E , Qian Y Y 
Published: December 2022

Abstract
Cyclosporin A (CsA) is an undecapeptide fungal metabolite and is generally regarded as a new generation of immunosuppressive drugs. We uncovered a novel immunomodulatory property of CsA as a potent immunologic stimulator in the murine IgE antibody system. The enhancement of IgE responses was observed in mice receiving as few as three daily i.m. injections before Ag priming. Our studies demonstrate the three points listed below. First, CsA potentiates murine IgE responses regardless of Ag specificities in inbred mice. A hierarchy of immunopotentiation by CsA follows the order of low, intermediate, and high IgE responder mice. Second, CsA, when administered along with Ag, exerts a thorough and long lasting impact on the Ag-specific IgE antibody response, and leads to an Ag-specific breakthrough of IgE antibody synthesis in mice rendered tolerant in the IgE antibody system by soluble Ag pretreatment or neonatal IgE treatment. Third, IgE enhancer cells become sensitive to a low dose of irradiation. Two enhancer cellular components are identified, those of the Th cells and B cells, which appear to favor the induction of IgE responses. Understanding the cellular basis of the immunopotentiating effect of CsA will provide further insight into the murine IgE antibody system.
Molecular characterization of a major autoantibody-associated cross-reactive idiotype in Sjogren's syndrome.
Authors: Kipps T J , Tomhave E , Chen P P , Fox R I 
Published: December 2022

Abstract
Primary Sjogren's syndrome is an autoimmune disorder characterized by lymphocytic infiltration of the salivary and lacrimal glands, producing associated dry eyes (keratoconjunctivitis sicca), dry mouth, and intermittently swollen salivary glands. A high proportion of the infiltrating B lymphocytes express surface and cytoplasmic Ig bearing a kappa-L chain-associated CRI defined by reactivity with the murine mAb, 17.109. To determine the structural basis for CRI expression in this disease, we generated CRI+ lymphoblastoid cell lines and a cDNA library from lymphocytes extracted from Sjogren's syndrome patients' salivary gland biopsy specimens. Nucleic acid sequence analyses of the mRNA of one such 17.109-CRI+ lymphoblastoid cell line (NOV) reveals the expressed kappa light chain variable region gene (V kappa gene) to be homologous to Humkv325, a conserved V kappa gene used at relatively high frequency in certain B cell malignancies. In addition, synthetic oligonucleotides, corresponding to the first and third frameworks and the second complementarity determining region of the Humkv325 gene, were used to identify and isolate clones from a cDNA library generated from SS salivary gland lymphocytes. Clones annealing specifically with one or more of these oligonucleotide probes contained kappa light chain cDNA. The sequences corresponding to the variable region of two clones (Taykv320 and Taykv306) were homologous to Humkv325. The V kappa genes of four other cDNA clones (Taykv322, Taykv310, Taykv308, and Taykv312) most likely were generated somatically from the rearranged Humkv325 gene through a limited number of nucleic acid base substitutions. Our results suggest that the high frequency of 17.109-CRI expression in Sjogren's syndrome patients results from a multiclonal expansion of B cells using Humkv325, and that the expressed Humkv325 may undergo somatic diversification in an apparent Ag-driven response.
Signal transduction pathway for IL-1. Involvement of a pertussis toxin-sensitive GTP-binding protein in the activation of adenylate cyclase.
Authors: Chedid M , Shirakawa F , Naylor P , Mizel S B 
Published: December 2022

Abstract
Human Il-1 alpha induces the synthesis of kappa Ig L chains by the pre-B cell line 7OZ/3, IL-2R alpha by the human NK cell line YT, and PGE2 by human rheumatoid synovial cells. Pertussis toxin (PT) markedly inhibited all three IL-1-induced activation events. The inhibition by PT was associated with a decrease in IL-1-mediated cAMP production. PT also inhibited IL-1-stimulated cAMP production in crude membrane fractions from 7OZ/3, YT, and 3T3 fibroblasts. In addition, IL-1 stimulated GTPase activity present in the membranes IL-1-responsive cells. Furthermore, the IL-1-induced GTPase activity was sensitive to PT. PT induced the ADP-ribosylation of a 46-kDa substrate in membrane preparations from IL-1-responsive cells. Cholera toxin also induced the ADP-ribosylation of a 46-kDa substrate in the same membrane preparations. The present findings indicate that the IL-1R is linked to a PT-sensitive G protein that stimulates the activity of adenylate cyclase.
Regulation of the growth rate of mouse fibroblasts by IL-3-activated mouse bone marrow-derived mast cells.
Authors: Dayton E T , Caulfield J P , Hein A , Austen K F , Stevens R L 
Published: December 2022

Abstract
When mouse bone marrow-derived mast cells (BMMC) are cocultured with a confluent layer of mouse 3T3 fibroblasts in the presence of WEHI-3-conditioned medium, the mast cells undergo a phenotypic change toward that of a connective tissue mast cell, and the fibroblasts increase their synthesis of globopentaosylceramide. We now demonstrate that fibroblasts lose their contact inhibition and multiply such that by the 2nd and the 4th wk of coculture there are, respectively, approximately four-fold and six-fold more fibroblasts than in the cultures that are not exposed to BMMC. This in vitro increase in the number of fibroblasts is dependent on the number of mast cells (over the range of 6 x 10(4) to 1 x 10(6) BMMC/culture) initially seeded with the fibroblasts and on the concentration of WEHI-3-conditioned medium present during the coculture. That the fibroblasts also multiply in BMMC/fibroblast cocultures exposed to synthetic IL-3 or to purified IL-3 indicates that IL-3 is a component in WEHI-3-conditioned medium that induces mast cells to produce the fibroblast growth factor. The number of fibroblasts does not increase if fibroblasts are exposed to lysates of BMMC, or to BMMC-derived conditioned medium, or if the two cell types are separated from one another during the coculture with a 3-microns filter or a 0.4-microns filter. Thus, IL-3-activated BMMC must be in proximity to fibroblasts to induce them to multiply. Because of their increased numbers per culture dish, total fibroblasts that were cocultured with mast cells synthesized approximately two-fold more 35S-labeled proteoglycans, incorporated approximately 3-fold more [3H] proline into collagenase-sensitive proteins, and had substantially more alpha 2(I) collagen mRNA than fibroblasts that were maintained in the absence of mast cells. These is vitro studies reveal a sequence by which IL-3-activated mast cells may play a role in the induction of fibrosis.
Binding of model immune complexes to erythrocyte CR1 facilitates immune complex uptake by U937 cells.
Authors: Emlen W , Burdick G , Carl V , Lachmann P J 
Published: December 2022

Abstract
The E C3b/C4b receptor (CR1) has been shown to rapidly bind large complement-fixing immune complexes (IC) both in vivo and in vitro. It has been proposed that E (RBC) CR1 act as a shuttle mechanism, binding circulating IC and transporting them to tissue macrophages, thereby preventing their deposition in target tissues. In this study we have established an in vitro model system with which to study the transfer of model IC from CR1 on the RBC surface to phagocytic cells. Aggregated IgG (AHG) was opsonized with C3b, bound to RBC CR1, and the binding of these RBC-bound IC by a human monocyte cell line (U937 cells) was examined. U937 binding of AHG from the RBC surface was complete within 2 min, whereas binding of the same AHG from solution required 30 to 60 min. Despite the difference in kinetics of binding, the total amount of IC bound by U937 cells at equilibrium was the same for RBC-bound AHG and for AHG in solution. The transfer of AHG from the RBC to the U937 cell did not require exogenous factor I and was not accompanied by binding of RBC to U937 cells or by erythrophagocytosis. Our data lend support to the hypothesis that binding of IC to RBC CR1 may facilitate the clearance of IC from the circulation by enhancing their uptake by phagocytic cells.
Depression of polymorphonuclear leukocyte functions by purified influenza virus hemagglutinin and sialic acid-binding lectins.
Authors: Cassidy L F , Lyles D S , Abramson J S 
Published: December 2022

Abstract
Infection of polymorphonuclear leukocytes (PMNL) with influenza virus causes depression of PMNL metabolic and bactericidal activities. The studies reported here were undertaken to determine whether the hemagglutinin (HA) glycoprotein of influenza virus mediates this depression. PMNL were incubated with purified HA and the oxidative responses to exogenous stimuli were measured. The results indicate that HA, in either liposomes or protein aggregates referred to as rosettes, depressed PMNL oxidative responses. Depression was observed within 2 min of initial interaction of HA with PMNL and lasted more than 2 h. The membrane fusion activity of HA requires proteolytic cleavage of the HA, whereas the receptor binding activity does not. There was no difference in the ability of virions with cleaved or uncleaved HA to depress PMNL responses suggesting that the fusion event is not required for PMNL dysfunction. Inasmuch as the HA glycoprotein binds to sialic acid-containing receptors on the surface of the PMNL, we tested whether other sialic acid-specific binding proteins can mediate the reduction of PMNL responses. Sialic acid-specific lectins from Limulus polyphemus or Limax flavus were incubated with PMNL before measuring their responses to secondary stimulus. Depression was observed upon incubation with the lectins similar to that seen upon incubation with the HA or influenza virus. These results suggest that attachment of influenza virus to sialic acid-containing receptors is responsible at least in part, for suppressing PMNL oxidative responses.
IgE receptor-mediated hydrolysis of phosphoinositides by cytoplasts from rat basophilic leukemia cells.
Authors: Dreskin S C , Pribluda V S , Metzger H 
Published: December 2022

Abstract
Cytoplasts (plasma membrane sacs containing cytoplasm, endoplasmic reticulum, and few organelles) were prepared from rat basophilic leukemia cells by treatment with cytochalasin B and centrifugation at 33 degrees C through stepwise gradients of Ficoll. To compare the relative ability of cytoplasts and cells to generate second-messengers (inositol phosphates, Ca2+) in response to stimulation of the high affinity receptor for IgE, we normalized our results per recovered receptor by using the tightly bound IgE as a marker. This marker correlated well with other estimates of plasma membrane recovery. Furthermore, data normalized on this basis correlated well with data expressed as percentage of phosphoinositides hydrolyzed. The purest fraction of cytoplasts (containing about 6% of the receptors) was satisfactorily devoid of organelles and, at early times, generated about 50% as much inositol phosphates per receptor as did the intact, untreated cells. This response of the cytoplasts, like that of the cells, was totally dependent upon aggregation of the receptors. The response by the cytoplasts (in the 5-min time frame which we examined), unlike that of the cells, was not enhanced by the presence of extracellular Ca2+. Furthermore, unlike the cells, the cytoplasts failed to raise their intracellular free Ca2+ levels after addition of polyvalent Ag. This result suggests that aggregation of the receptors may be insufficient, by itself, to open the normal Ca2+ channels.
Variations in protein expression related to human eosinophil heterogeneity.
Authors: Gruart V , Balloul J M , Prin L , Tomassini M , Loiseau S , Capron A , Capron M 
Published: December 2022

Abstract
In hypereosinophilic patients, eosinophil heterogeneity has been assessed mainly according to morphologic and biologic criteria. In order to investigate the molecular basis of such heterogeneity, biochemical analysis was performed on various eosinophil subpopulations fractionated on metrizamide gradients. Whole cell extracts from purified eosinophils disrupted with a nonionic (NP-40) detergent were successively analyzed by SDS-PAGE and two-dimensional electrophoresis (isoelectric focusing or nonequilibrium pH gradient electrophoresis in the first dimension). Hypodense eosinophils that sediment in the lightest density gradients (18 to 22% metrizamide solution) differed from other purified eosinophils (intermediate and normodense eosinophils respectively collected in 22 to 23% and 23 to 25% metrizamide solutions). Comparative analysis of protein patterns on both monodimensional and bidimensional electrophoresis showed that a basic protein of Mr 51 kDa, present on normodense or intermediate eosinophils, was poorly detected in the case of hypodense eosinophils. In contrast, two other proteins with apparent Mr of about 23 kDa and 41 kDa were exclusively or predominantly identified in these latter cell fractions. Immunochemical analysis with polyclonal antibodies against eosinophil basic proteins and enzymatic assays revealed that the 51-kDa polypeptide could be related to an eosinophil peroxidase-like molecule. In addition, the two proteins detected only in hypodense eosinophils might be related to proteins newly synthesized by in vivo activated eosinophils. Our results suggest that variations in protein expression might represent a good marker of in vivo activation.
Functional role of human IgG subclasses in eosinophil-mediated killing of schistosomula of Schistosoma mansoni.
Authors: Khalife J , Dunne D W , Richardson B A , Mazza G , Thorne K J , Capron A , Butterworth A E 
Published: December 2022

Abstract
Although IgG antibodies and eosinophils have been shown to kill schistosomula of Schistosoma mansoni in vitro, very little data exist that describe the role of each IgG antibody isotype in this event. This study was designed to test the role of each IgG subclass in the eosinophil-dependent killing reaction. IgG antibodies purified by protein G or protein A affinity chromatography demonstrated a killing effect only in the presence of eosinophils activated in vivo or normal eosinophils activated in vitro by eosinophil activating factor. Purification of each IgG isotype allowed confirmation of these results and demonstrated that the killing effect was associated with IgG1 and IgG3 antibodies. IgG2 antibodies expressed a dual function: 1) an effector function with activated eosinophils and 2) a blocking function with normal eosinophils. IgG4 antibodies, whatever the source of eosinophils, blocked the killing mediated by IgG effector antibodies. These findings are discussed in relation to immunity and susceptibility to reinfection in human schistosomiasis.
Antibacterial properties of eosinophil major basic protein and eosinophil cationic protein.
Authors: Lehrer R I , Szklarek D , Barton A , Ganz T , Hamann K J , Gleich G J 
Published: December 2022

Abstract
We examined the bactericidal activity of two proteins that are abundant in the cytoplasmic granules of human eosinophils, major basic protein (MBP) and eosinophil cationic protein (ECP). Unlike the human neutrophil's peptide defensins, both MBP and ECP killed stationary phase Staphylococcus aureus 502A in a simple nutrient-free buffer solution. Although MBP also killed Escherichia coli ML-35 with considerable efficacy under these experimental conditions, the in vitro activity of ECP against E. coli was considerably enhanced if mid-logarithmic phase bacteria replaced stationary phase organisms or if the assay medium was enriched with trypticase soy broth. The antibacterial activity of both eosinophil proteins was modulated by incubation time, protein concentration, temperature and pH. A pBR322-transformed derivative of E. coli ML-35 was used to examine the effects of ECP and MBP on integrity of the bacterial inner membrane (IM) and outer membrane. Although both MBP and ECP caused outer and inner membrane permeabilization when nutrients were present, only MBP was effective under nutrient-free conditions. Two proton ionophores (DNP and carbonyl cyanide m-chlorophenyl hydrazone) protected E. coli from the bactericidal effects of ECP but not from MBP. These findings establish that MBP and ECP have bactericidal properties and suggest that these proteins kill E. coli by similar but nonidentical mechanisms marked by an attack on the target cell's membranes. In view of evidence that high concentrations of ECP and MBP exist in cytoplasmic granules whose contents are translocated to phagocytic vacuoles, we suggest that MBP and ECP contribute to the eosinophil's ability to kill ingested bacteria.
Mouse hepatitis virus 3 replication in T and B lymphocytes correlate with viral pathogenicity.
Authors: Lamontagne L , Descoteaux J P , Jolicoeur P 
Published: December 2022

Abstract
Viral pathogenicity may be regulated by host defense mechanisms at the virus-immune cell interaction level. The immune system plays an important role in the outcome of acute disease induced by the mouse hepatitis virus type 3 (MHV3) virus. The lymphoid cells act as effectors in the virus elimination as well as targets for viral replication. In order to demonstrate a correlation between MHV3 pathogenicity and viral replication in lymphocytes, genetically-determined resistant A/J and susceptible C57BL/6 mice were infected with pathogenic (L2-MHV3) or nonpathogenic (YAC-MHV3) viral strains. Pathogenicity and histopathologic studies have revealed that lymphoid organs such as thymus and spleen, showed injuries or atrophy in susceptible mice infected with L2-MHV3. No histopathologic lesions in the lymphoid organs occurred in C57BL/6 mice infected with YAC-MHV3 or A/J mice infected with both viruses. The mechanisms involved in the lymphoid injuries were studied regarding viral replication in the lymphoid organs and cells in infected mice. Results indicate that cell depletion in lymphoid organs is caused by a complete viral replication in lymphoid cells. Thy1.2+ and surface IgM+ lymphoid cells from susceptible C57BL/6 mice infected with L2-MHV3 were permissive to viral replication and to subsequent cell lysis. No cell lysis, however, occurred in lymphoid cells from C57BL/6 mice infected with YAC-MHV3 and A/J mice infected with both virus strains. In vitro studies, with purified T and B cell populations were performed to determine the mechanism effecting susceptibility or resistance to viral-induced cell lysis occurring in such cells. A blockade, probably occurring at the viral RNA polymerase activity level, prevents viral replication in resistant cells between the stages of fixation of the virus at the cell-surface receptor and the viral protein translation. These experiments indicate that an intrinsic virus-specific resistant mechanism occurs in lymphoid cells that plays a major role in the viral pathogenicity.
Diversity of Ig V gene segments found in anti-DNA autoantibodies from a single (NZB x NZW)F1 mouse.
Authors: Panosian-Sahakian N , Klotz J L , Ebling F , Kronenberg M , Hahn B 
Published: December 2022

Abstract
We have studied 18 anti-DNA secreting hybridomas derived from a single, nephritic NZB/NZW mouse. The antibodies were analyzed for the expression of idiotypic families that are enriched in the antibodies to DNA from diseased animals (IdGN2 and IdX), and for the expression of VH and V kappa gene segment subfamilies. Most of the mAb have characteristics similar to those that may be pathogenic because they 1) bound to native DNA, 2) were of the IgG2a or IgG2b isotype, and 3) expressed idiotopes associated with glomerulonephritis in NZB/NZW mice and human lupus. Among the 18 mAb, at least six VH subfamilies and six V kappa subfamilies were expressed. A majority of the antibodies utilized a VH gene segment from the large J558 subfamily. Slot blot analyses of total spleen cell RNA revealed that as NZB/NZW mice aged and developed nephritis, they expressed progressively higher quantities of Ig transcripts. The proportion of these transcripts derived from the VH J558 subfamily also increased. Our results indicate that a diversity of B cell clones participate in the anti-DNA response of a single NZB/NZW mouse. There was no preferential utilization of 3' Ig V gene segment subfamilies. Furthermore, there was no marked difference in the pattern of VH and V kappa gene segment expression in antibodies defined by their isotypes or idiotopes.