bluuebunny/crossref_metadata_2025_split huggingface dataset:
Egr-1 expression in surface Ig-mediated B cell activation. Kinetics and association with protein kinase C activation.
Authors: Seyfert V L , McMahon S , Glenn W , Cao X M , Sukhatme V P , Monroe J G 
Published: December 2022

Abstract
We have studied the expression of an immediate/early type gene, Egr-1, in murine B lymphocyte responses to Ag receptor-generated signals. The Egr-1 gene encodes a zinc finger protein with sequence-specific DNA binding activity and is believed to act as an intracellular "third messenger," to couple receptor-generated signals to activation-associated changes in gene expression. We show here that Egr-1 mRNA expression is rapidly and transiently (returning to basal levels by 6 h) induced after receptor crosslinking with anti-receptor antibodies. Egr-1 protein expression is more prolonged, maintaining detectable levels through 12 h. The induction of Egr-1 is a primary response to Ag receptor signaling, as it is independent of new protein synthesis and is inhibited by actinomycin D. We have also examined the linkage of Egr-1 to known signaling pathways associated with G0 to G1 transition by these cells in response to signals generated through the B cell Ag receptor. Egr-1 mRNA was not induced after elevation of intracellular free Ca2+. In contrast, the pharmacologic agents PMA and SC-9, which directly activate protein kinase C, both cause marked increases in Egr-1 mRNA levels with the same kinetics as observed after anti-receptor antibody stimulation. Further, the protein kinase C inhibitors H7, sangivamycin, and staurosporin block anti-receptor antibody-induced expression of Egr-1, thus, B cell Ag receptor-linked Egr-1 expression is likely coupled to the protein kinase C component of transmembrane signaling. Preliminary promoter mapping studies are consistent with this conclusion, because both PMA and anti-receptor antibody act through the same or overlapping cis-regulatory elements.
Differentiation of hematopoietic stem cells in irradiated mouse thymic lobes. Kinetics and phenotype of progeny.
Authors: Spangrude G J , Scollay R 
Published: December 2022

Abstract
To define cell populations which participate in the very early stages of T cell development in the mouse thymus, we enriched hematopoietic stem cells from mouse bone marrow and injected them into thymic lobes of irradiated Ly-5 congenic recipients. The progeny of the stem cells were identified and their phenotypes were determined by two-color flow cytometry for the expression of various cell surface differentiation Ag during the course of their subsequent intrathymic development. The majority of the differentiation which occurred in the first 10 days after intrathymic cell transfer was myeloid in nature; hence, this study demonstrates that the irradiated thymus is not strictly selective for T cell development. Further, the maximum rate of T cell development was observed after intrathymic injection of 200 stem cells. Donor-derived cells which did not express Ag characteristic of the myeloid lineage could be detected and their phenotypes could be determined by flow cytometry as early as 7 days after intrathymic injection. At this time, the cells were still very similar phenotypically to the bone marrow hematopoietic stem cells. Exceptions to this were the expression of stem cell Ag 2 and a decrease in the level of MHC class I Ag expression. After 9 days, the donor-derived cells expressed high levels of the Thy-1 Ag and proceeded to change in cell surface phenotype as differentiation continued. These cell phenotypes are described for the time frame ending 18 days after injection, when most donor-derived cells were phenotypically small CD4+ CD8+ (double-positive) thymocytes.
The CD24 antigen discriminates between pre-B and B cells in human bone marrow.
Authors: Duperray C , Boiron J M , Boucheix C , Cantaloube J F , Lavabre-Bertrand T , Attal M , Brochier J , Maraninchi D , Bataille R , Klein B 
Published: December 2022

Abstract
When bone marrow (BM) lymphoid cells from 12 adult healthy donors were labeled by CD24 antibodies and analyzed by flow cytometry, two positive populations of cells were demonstrated in each sample (by a separated bimodal specific immunofluorescence). One population had intermediate CD24-Ag density (termed CD24+ cells) whereas the other had high CD24-Ag density (termed CD24(2+) cells). CD24+ cells represented 5.8 +/- 2.7% of the total lymphoid BM cells and CD24(2+) cells 5.6 +/- 2.5%. Using dual fluorescence analysis on eight samples, all CD24+ cells expressed the CD21 and CD37 mature B cell Ag and also surface IgM (sIgM), but this population lacked CD10 Ag. These cells also expressed CD19 Ag, and at a higher density than CD24(2+) cells. They were also positive for HLA-DR Ag. Conversely, CD24(2+) cells were shown to be early cells of the B cell lineage. While all the CD24(2+) cells were HLA-DR+ and CD19+, 64 +/- 16% of them expressed CD20 Ag (at a lower density than CD24+ cells), 65 +/- 21% CD10 Ag, and 22 +/- 8% were positive for cytoplasmic mu-chains (c mu). None of these cells expressed the CD21 and CD37 mature B cell Ag or sIgM. Additional experiments on four different healthy donors demonstrated that 30 +/- 9% of the CD24(2+) cells expressed the CD34 Ag and that the CD24+ cells did not express it. Thus, the CD24 Ag permits discrimination between two populations of the B cell lineage present in adult BM: 1) A CD24(2+) cell population including "pre" pre-B cells (HLA-DR+, CD19+, CD10+/-, CD20-, CD21-, CD34+, CD37-, c mu-), "intermediate" pre-B cells (HLA-DR+, CD19+, CD10+, CD20+, CD21-, CD34-, CD37-, c mu-), and "true" pre-B cells (HLA-DR+, CD19+, CD10+, CD20+, CD21-, CD34-, CD37-, c mu+). 2) A CD24+ cell population including B cells of the standard phenotype (HLA-DR+, CD19+, CD10-, CD20+, CD21+, CD34-, CD37+, c mu-, sIgM+).
Functional expression of HLA-C blank antigens on human blood lymphocytes.
Authors: Kariyone A , Tanabe M , Juji T , Kano K , Takiguchi M 
Published: December 2022

Abstract
The surface expression of two HLA-C blank Ag (Cb-1 and Cb-2) on PBL was investigated with Cb-1- and Cb-2-specific CTL clones generated by the stimulation of the HLA-C blank Ag on transfected Hmy2CIR cells. The Cb-1- and Cb-2-specific CTL clones could lyse EBV-transformed B cells and PHA-induced T cells from which the HLA-C blank genes were derived. Furthermore, the reactivity of these CTL clones with PHA-induced T cells was blocked by HLA class I monomorphic mAb. These results demonstrated that the HLA-C blank Ag are expressed on the surfaces of PBL. Thus, despite the fact that the HLA-C blank Ag are expressed on normal PBL, they are incapable of generating corresponding alloantibodies. On the other hand, the present study demonstrated that these Ag on normal PBL are able to induce specific CTL and that the capacity of these Ag to induce allogeneic CTL is almost identical to that of HLA-B Ag, indicating that they may function as alloantigens in vivo and play a significant role in the rejection of organ grafts and in the graft-versus-host reaction in bone marrow transplantation.
Binding of IL-1 beta to alpha-macroglobulins and release by thioredoxin.
Authors: Borth W , Scheer B , Urbansky A , Luger T A , Sottrup-Jensen L 
Published: December 2022

Abstract
Human alpha 2-macroglobulin (H alpha 2M) is a major IL-1 beta binding plasma protein. The characteristics of the H alpha 2M IL-1 beta complex formation suggested, that cleavage of the internal thiol ester in other members of the alpha-macroglobulin family (alpha M) could enable these proteins to bind IL-1 beta. Characterization of optimal conditions for binding 125I IL-1 beta to H alpha 2M showed that H alpha 2M-IL-1 beta complex formation could be obtained over a pH range of 6.3 to 9 in the presence of some metal cations (i.e., Zn2+, Cd2+, Cu2+, Ni2+). Other divalent metal cations (i.e., Mn2+, Mg2+, Ca2+) were without effect. Time kinetic studies showed that binding of IL-1 beta to H alpha 2M was complete within 200 min and that H alpha 2M-IL-1 beta complexes became increasingly resistant to dissociation by boiling in SDS as a function of incubation time. Human pregnancy zone protein, rat alpha 1-, alpha 2-macroglobulin (R alpha 1M, R alpha 2M), all homologous with H alpha 2M, were tested for their ability to bind IL-1 beta. In each instance, alpha M-IL-1 beta complex formation was observed only after treatment of alpha M with methylamine, a primary amine that causes cleavage of the internal thiol ester in alpha M and the appearance of free thiol groups. Similarly, for each of these proteins, complex formation was increased several fold in the presence of Zn2+. Competition experiments using cytokines or proteins of similar molecular mass as IL-1 beta established that only unlabeled IL-1 beta was effective in inhibiting binding of 125I IL-1 beta to H"F" alpha 2M. Acylation of H"F" alpha 2M by diethylpyrocarbonate blocked the binding of IL-1 beta when analyzed by native PAGE. Deacylation of H"F" alpha 2M with hydroxylamine partially restored the binding capacity of H"F" alpha 2M further supporting the involvement of histidyl residues in the Zn2(+)-dependent binding of IL-1 beta. Reduced thioredoxin, but not its alkylated form, from Escherichia coli readily releases H"F" alpha 2M bound IL-1 beta under conditions that did not lead to reduction of disulfide bonds in H"F" alpha 2M. The action of thioredoxin also augmented IL-1-like activity in two independent bioassays suggesting that H"F" alpha 2M bound IL-1 beta is partially biologically inactive or latent. These results suggest that "activated" alpha M exert a modulating role for IL-1 beta by exposing specific binding sites, which are inaccessible in the native proteins.(ABSTRACT TRUNCATED AT 400 WORDS)
Antigen-induced cross-linking of the IgE receptor leads to an association with the detergent-insoluble membrane skeleton of rat basophilic leukemia (RBL-2H3) cells.
Authors: Apgar J R 
Published: December 2022

Abstract
Cross-linking of the IgE receptor on the surface of rat basophilic leukemia cells by multivalent Ag (DNP-BSA) causes a rapid conversion to a detergent-insoluble form. There is a concurrent increase in the amount of filamentous actin associated with the plasma membrane. Both the degree of receptor detergent insolubility and the rise in F-actin content are rapid with a half-maximal response of less than 1 min and can be rapidly reversed by the addition of monovalent Ag (DNP-lysine). These two early steps in the triggering of rat basophilic leukemia cells can be dissociated from each other by pretreatment of the cells with either cytochalasin or sodium azide. These reagents block the increase in F-actin but have no effect on receptor detergent insolubility. This indicates that microfilaments are not responsible for detergent insolubility of the receptor and that it may be the membrane skeleton that is interacting with the complex. This was further confirmed by the finding that cross-linking of the IgE receptors on the surface of purified plasma membranes also leads to detergent insolubility of the receptor. Therefore, all of the components necessary for detergent insolubility of the receptor are present in the plasma membrane, and cytoplasmic components are not needed. These results suggest that detergent insolubility and immobility of the cross-linked receptors are caused by multivalent interaction with the membrane skeleton. Actin filaments may then interact with these receptor-membrane skeletal complexes in order to produce large scale clustering and capping. The membrane skeleton may therefore be acting as an intermediate structure between the cell-surface receptors and microfilaments.
Priming of the respiratory burst in human eosinophils is accompanied by changes in signal transduction.
Authors: Koenderman L , Tool A T , Roos D , Verhoeven A J 
Published: December 2022

Abstract
Addition of platelet-activating factor (PAF) to human eosinophils leads to the modulation of eosinophil responses. The respiratory burst, induced by opsonized particles, consists of an initiation and a propagation phase and is greatly enhanced ("primed") after pretreatment with PAF. This priming event induces the following changes in signal transduction between the opsonin receptors (in particular the CR3 receptor) and activation of the respiratory burst: 1) an enhanced activation of protein kinase C (PK-C): the initiation of the respiratory burst in untreated eosinophils is not sensitive to PK-C inhibition (via staurosporine) and is not accompanied by accumulation of diglycerides and changes in [Ca2+]i. After pretreatment with PAF, the initiation of the response is partly sensitive to inhibition of PK-C (via staurosporine) and is accompanied by accumulation of diglycerides and a fast and sustained increase in [Ca2+]i; and 2) an enhancement of a PK-C-independent initiation of the respiratory burst. The propagation phase in both primed and unprimed cells is sensitive for inhibition by staurosporine. Our results indicate that in eosinophils the phospholipase(s) responsible for the accumulation of the diglycerides and changes in [Ca2+]i during the initiation phase of the serum-treated zymosan response seem(s) to become associated with the signal transduction route only after priming with PAF. This results in the occurrence of two signal transduction routes that can act independently of each other.
Ia-independent binding of peptide antigen to the T cell receptor.
Authors: Esch T R , Thomas D W 
Published: December 2022

Abstract
We have investigated the potential for direct interaction between a peptide Ag, human fibrinopeptide B (hFPB), and the TCR on an hFPB-specific murine T hybridoma. Fluoresceinated hFPB binds specifically to hFPB-responsive T cells, but not to unrelated T hybrids. Among variant subclones of the original hybridoma, ability to bind hFPB correlates with hFPB-specific response and expression of the CD3/TCR complex, indicating that hFPB is binding to the TCR. This TCR-hFPB interaction has an affinity of approximately 6.6 microM, reflecting slow association and rapid dissociation of the Ag from its receptor. These findings confirm the potential for direct Ag-TCR interaction and indicate an Ag recognition mechanism that is not initiated by Ag-MHC interaction.
Evidence for involvement of clonal anergy in MHC class I and class II disparate skin allograft tolerance after the termination of intrathymic clonal deletion.
Authors: Tomita Y , Nishimura Y , Harada N , Eto M , Ayukawa K , Yoshikai Y , Nomoto K 
Published: December 2022

Abstract
Mechanisms of cyclophosphamide (CP)-induced tolerance to class I (D) and class II (IE) alloantigens were studied. Transplantation tolerance across H-2D plus IE Ag-barriers has been achieved when B10.Thy-1.1 (Kb,IAb,IE-,Db; Thy-1.1) mice were primed i.v. with 9 x 10(7) spleen cells plus 3 x 10(7) bone marrow cells from B10.A(5R) mice (5R; kb,IAb,IEb,Dd; Thy-1.2) and treated i.p. with 200 mg/kg of CP 2 days later. The tolerant state in the early and the late stage was confirmed by prolonged acceptance of donor-type skin grafts, and in vitro unresponsiveness to donor Ag. In the tolerant B10.Thy-1.1 mice treated with 5R cells 28 days earlier and followed by CP, intrathymic clonal deletion of V beta 11+ T cells reactive to IE-encoded antigens was observed in association with intrathymic mixed chimerism. 5R skin survived, however, even after the clonal deletion of V beta 11+ T cells terminated by 180 days after tolerance induction. V beta 11+ T cells, which reappeared in the periphery of the recipient B10.Thy-1.1 mice bearing 5R skin at this stage, were not capable of proliferating in response to receptor cross-linking with V beta 11-specific mAb. Furthermore, the CTL activity against class I (Dd) alloantigens of spleen cells from these tolerant mice was restored by the addition of IL-2 to MLC. Thus, our experiments provide direct evidence that tolerance to both class I (Dd) and class II (IEb) alloantigens by clonal allergy occurs during the termination of intrathymic clonal deletion. These results clearly show practical hierarchy of the mechanisms of transplantation tolerance.
1,25(OH)2 vitamin D3 inhibits the CD23 gene expression by human peripheral blood monocytes.
Authors: Fargeas C , Wu C Y , Luo H Y , Sarfati M , Delespesse G , Wu J P 
Published: December 2022

Abstract
A biologically active form of vitamin D, 1,25(OH)2D3, and a leukocyte surface molecule, CD23, play important roles in immune regulation. The effect of 1,25(OH)2D3 on the CD23 gene expression was examined in this study. The results show that 1,25(OH)2D3 suppresses spontaneous and IL-4-stimulated CD23 synthesis by peripheral blood monocytes. The inhibition occurs at both the protein and mRNA levels. However, 1,25(OH)2D3 has no inhibitory effect on CD23 production by either resting or activated tonsillar B cells. Our results suggest a possible role of 1,25(OH)2D3 in the regulation of certain immune and inflammatory responses via its effect on CD23 production.
Identification of an epitope of type 1 streptococcal M protein that is shared with a 43-kDa protein of human myocardium and renal glomeruli.
Authors: Kraus W , Dale J B , Beachey E H 
Published: December 2022

Abstract
The localization of opsonic and tissue-cross-reactive epitopes within the amino terminus of type 1 streptococcal M protein was investigated by using murine mAb raised against synthetic peptides of type 1 M protein. Two mAb (IIIA2 and IIIB8) reacted with epitopes located within amino acid residues 1-12 of type 1 M protein. These antibodies opsonized type 1 streptococci and did not cross-react with human kidney and heart tissue. Another mAb (IC7) reacted with mesangial cells of renal glomeruli and human myocardium. The cross-reactive epitope of mAb IC7 was localized to position 13-19, indicating that it is not the same epitope as the previously described vimentin-cross-reactive epitope at position 23-26 of type 1 M protein. In Western blots of mesangial cell and myocardial proteins, mAb IC7 cross-reacted with a 43-kDa protein. Neither vimentin nor actin inhibited the binding of mAb IC7 to the cross-reactive protein, as determined by Western blot or immunofluorescence inhibition tests. These results provide evidence that type 1 M protein contains at least one autoimmune epitope shared with both human glomeruli and myocardium.
Cardiac myosin-induced myocarditis. Heart autoantibodies are not involved in the induction of the disease.
Authors: Neu N , Ploier B , Ofner C 
Published: December 2022

Abstract
We recently demonstrated that cardiac myosin is capable of inducing autoimmune myocarditis in genetically predisposed mice. This disease parallels coxsackievirus B3-induced autoimmune myocarditis in many respects and is associated with high-titer autoantibodies specific for cardiac myosin. The following lines of evidence suggest that these autoantibodies are not involved in the induction of autoimmune myocarditis: 1) immunoperoxidase staining of heart sections from cardiac myosin-immunized A/J and A.SW mice revealed IgG depositions only along damaged muscle fibres in infiltrated areas, but not in intact tissue; 2) myosin autoantibodies did not bind to the surface of viable cardiac myocytes isolated from mice, but only reacted with myocytes permeabilized with detergent; 3) mice treated with a single high dose of cyclophosphamide, which reduces the humoral immune response, still developed severe myocarditis, despite the fact that their autoantibody titers were reduced to the level of adjuvant-injected controls; and 4) passive transfer of high-titer myosin autoantibodies failed to induce myocarditis, although the titers in the recipients were comparable to those found in mice with cardiac myosin-induced disease. Together, the results suggest that high-titer myosin autoantibodies are secondary rather than primary to the disease.
Functional consequences of cAMP accumulation in human natural killer cells. Implications for IL-2 and IL-4 signal transduction.
Authors: Vitté-Mony I , Stancou R , Bertoglio J H 
Published: December 2022

Abstract
To approach the mechanisms whereby IL-2 activates human NK cells, we have compared the effects of IL-4 and of Bt2cAMP on this activation. Both agents block completely the proliferation induced by IL-2 on highly purified CD3-negative human NK cells. We also report that the net LAK response of PBL is inhibited by IL-4 and cAMP. However, kinetics analysis showed that IL-4 appears to inhibit an early stage of IL-2-induced activation of NK cells. IL-4 does not affect the cytotoxicity of freshly isolated NK cells against the K562 target and is ineffective on IL-2-preactivated cells. In contrast, cAMP primarily blocks the lytic effector phase, whether cells have been cultured in IL-2 or not, and its effect appears independent of time of addition. These differences between the activity of IL-4 and cAMP suggested that cAMP was not directly involved in IL-4 signal transduction in human NK cells. Consistent with this interpretation, we did not observe any variation in the level of intracellular cAMP concentrations when NK cells were stimulated with IL-4, or when they are stimulated with IL-2 or IL-2 plus IL-4. In addition, we also demonstrate that NK cell cytotoxic activation induced by IL-2 is still demonstrable in the presence of Bt2cAMP under conditions in which NK cell proliferation is blocked. These results clearly indicate that the differentiative effect of IL-2 on NK cells is independent of cell proliferation. Furthermore, the p70-75 IL-2R-initiated signal transduction pathway that leads to increased cytotoxicity appears not to be susceptible to inhibition by cAMP in human NK cells.
Leishmania major amastigotes initiate the L-arginine-dependent killing mechanism in IFN-gamma-stimulated macrophages by induction of tumor necrosis factor-alpha.
Authors: Green S J , Crawford R M , Hockmeyer J T , Meltzer M S , Nacy C A 
Published: December 2022

Abstract
Macrophages exposed to IFN-gamma and infected with amastigotes of Leishmania major develop the capacity to eliminate the intracellular pathogen. This antimicrobial activity of activated macrophages correlates with the initiation of nitrogen oxidation of L-arginine, yet other reports suggest that two signals are required for induction of this biochemical pathway for effector activity. In the present studies, macrophages treated with up to 100 U/ml IFN-gamma, or 100 ng LPS, or 10(7) amastigotes produced minimal quantities (less than 9 microM) of NO2- and failed to develop cytotoxic effector activities. In contrast, the combination of IFN-gamma and either LPS (greater than 0.1 ng) or amastigotes (10(6) induced high concentrations (much greater than 30 microM) of NO2- and macrophage cytotoxicity against intra- and extracellular targets. The induction of nitrogen oxidation by amastigotes could be dissociated from LPS-induced events by 1) performing the assays in the presence of polymyxin B (which blocked LPS effects, but not amastigote effects), 2) determining the threshold of IFN-gamma required to prime cells for subsequent trigger (1 U/ml for LPS trigger effects; 10-fold higher for amastigotes), and 3) determining the heat sensitivity of the two trigger agents (amastigote effects abolished at 100 degrees C; LPS effects unaffected at this temperature). Further, culture fluids from amastigote-infected macrophages did not contain detectable LPS (less than 6 pg/ml). Possible parasite and cell-associated factors that could contribute to the induction of nitrogen oxidation and cytotoxic activity of IFN-gamma treated macrophages were examined: only certain intact microorganisms, LPS from a variety of bacteria, and the cytokine TNF alpha were effective. Both NO2- production and intracellular killing were abolished by the addition of anti-TNF-alpha mAb in the assay. TNF-alpha was produced by amastigote-infected macrophages and IFN-gamma dramatically enhanced secretion of this cytokine; IFN-gamma alone had no effect. Endogenous TNF-alpha produced during infection of macrophages with L. major acted in an autocrine fashion to trigger the production of L-arginine-derived toxic nitrogen intermediates that killed the intracellular parasites.