bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mast cells expressing chymase but not tryptase can be derived by culturing human progenitors in conditioned medium obtained from a human mastocytosis cell strain with c-kit ligand.
Authors: Li L , Meng X W , Krilis S A 
Published: December 2022

Abstract
Human mast cells (MC) were derived from umbilical cord blood and bone marrow progenitors cultured in the presence of a conditioned medium from a human mastocytosis cell strain and recombinant human kit ligand. MCs were studied using a sequential double immunoenzymatic analysis to determine the heterogeneity of expression of tryptase and chymase, two MC-specific proteases. The conditioned medium and kit ligand promoted the development of distinct MC subtypes from bone marrow and umbilical cord blood progenitors. kit ligand induced MC from umbilical cord blood predominantly of two immunophenotypes, MCT positive for tryptase but negative for chymase, and MCTC positive for tryptase and chymase. In contrast, the conditioned medium induced MC subtype MCTC and a third subtype, MCC, positive for chymase but negative for tryptase from both bone marrow and umbilical cord blood progenitors. In situ hybridization analyses confirmed the existence of a chymase-positive, tryptase-negative human MC in the culture. In umbilical cord blood cultures supplemented with both conditioned medium and kit ligand, the number of MCC cells was up-regulated from 2.7 to 34.0% of the total cells in the culture. In contrast, the number of MCT cells declined from 54.3 to 21.5% on day 49 of culture. In bone marrow cultures supplemented with conditioned medium alone, the MCC subtype represented 100% of the MCs on day 10 of culture. This study clearly demonstrates that a third type of MC, MCC, expressing chymase without concomitant expression of tryptase can be induced in vitro from normal human progenitors. In addition, it shows that tryptase and chymase, two MC-specific proteases, can be differentially expressed in in vitro derived human MCs by changing the cytokine combination of the culture.
The IL-1 and IL-1 receptor antagonist (IL-1Ra) response of human neutrophils to EBV stimulation. Preponderance of IL-Ra detection.
Authors: Roberge C J , Poubelle P E , Beaulieu A D , Heitz D , Gosselin J 
Published: December 2022

Abstract
The present study investigated the effect of EBV on gene expression and protein synthesis of IL-1 and its natural IL-1R antagonist (IL-1Ra) in human peripheral blood neutrophils. EBV induced a rapid accumulation of IL-1 and IL-lRa mRNA in neutrophils that was associated with the later appearance of considerable amounts of IL-1alpha, IL-1beta, and IL-Ra proteins. Approximately 3200 and 610 times more IL-Ra than IL-1alpha a or IL-1beta, respectively, was secreted by neutrophils in response to EBV. The effect induced by EBV cannot reflect an overall metabolic activity of neutrophils, since EBV failed to induce granulocyte-macrophage OF synthesis. Heat-inactivated virus was unable to stimulate cytokine synthesis, whereas UV-irradiated virus retained the full IL-1- and IL-1Ra-inducing potential of the native particle. Furthermore, pretreatment of cells with cycloheximide or phosphonoacetic acid did not abrogate the effect of EBV, suggesting that EBV does not penetrate the cell, but that a virion's structural molecule is required to induce such an effect. In this respect, neutralization of the viral particles with the mAb 72A1, which is known to react with glycoprotein gp350 of the viral envelope, inhibits the production of IL-1 and IL-1Ra, suggesting that gp350 could be involved in this process. Thus, the elevated levels of IL-1Ra detected for EBV-stimulated neutrophils might be part of a mechanism used by the virus to evade the immune system.
Tolerance to rat liver allografts. III. Donor cell migration and tolerance-associated cytokine production in peripheral lymphoid tissues.
Authors: Bishop G A , Sun J , DeCruz D J , Rokahr K L , Sedgwick J D , Sheil A G , Gallagher N D , McCaughan G W 
Published: December 2022

Abstract
The aim of this work was to investigate the mechanism of spontaneous rat liver allograft tolerance. Liver allografts from a LEW donor into DA recipient (LEW--&gt;DA) or of PVG--&gt;DA were spontaneously tolerated (TOL) across a complete MHC mismatch. In contrast, DA--&gt;LEW or PVG--&gt;LEW liver allografts were rejected in 10 to 15 days (REJ). We examined whether donor cell migration to recipient lymphoid tissues might be associated with TOL. Many donor cells were observed in draining (celiac) lymph nodes (LN) and spleen, reaching a peak on day 1 and then decreasing rapidly thereafter. Irradiation of liver donors, which we have previously shown to delete tolerance, significantly reduced the number of donor leukocytes in recipient lymphoid tissues. While this suggested an association between donor cell migration and tolerance, the number, distribution, and type of donor cells in recipient lymphoid tissues of REJ was similar to those of TOL. Expression of cytokine mRNA in LN and spleen showed an early increase in the expression of IL-2 and IFN-gamma mRNA on day 1 and then a rapid decrease to constitutive levels. Spleen and LN levels of IL-6, IL-10, TNF-alpha, or TGF-beta mRNA showed much less up-regulation than IL-2 or IFN-gamma. Paradoxically, there was greater expression of IL-2 and IFN-gamma mRNA in TOL lymphoid tissues than in REJ, and this superinduction was partially prevented by donor irradiation. Superinduction of IL-2 and IFN-gamma was, therefore, more closely associated with TOL than was donor cell migration. This was confirmed by treatment of TOL recipients with a short course of methylprednisolone, which reduced survival of subsequent donor strain skin grafts. This finding has implications for treatment of human liver transplants and is evidence for a novel pathway of transplant tolerance.
Release of bactericidal/permeability-increasing protein in experimental endotoxemia and clinical sepsis. Role of tumor necrosis factor.
Authors: von der Möhlen M A , van der Poll T , Jansen J , Levi M , van Deventer S J 
Published: December 2022

Abstract
Bactericidal/permeability-increasing protein (BP]) is contained within the azurophilic granules of neutrophils and is able to neutralize endotoxin and kill Gram-negative bacteria. TNF has been implicated as a mediator of endotoxin-induced neutrophil degranulation. To assess the role of TNF in the elevated BPI levels during sepsis, the following studies were performed. 1) In 31 consecutive patients with sepsis syndrome, plasma BPI levels were markedly elevated compared with those in healthy controls, but showed no correlation with simultaneously measured TNF concentrations. 2) In four healthy men, i.v. injection of recombinant human TNF (50 microg/m2) induced a rapid rise in plasma BPI levels. 3) In eight normal subjects, i.v. administration of Escherichia coli endotoxin (4 ng/kg) elicited subsequent increases in the plasma concentrations of TNF and BPI. 4) Eight healthy chimpanzees were investigated after i.v. injection of endotoxin (4 ng/kg); four animals received endotoxin only, and four animals received an anti-TNF mAb simultaneously. Although anti-TNF completely prevented the endotoxin-induced appearance of TNF activity, the rise in BPI levels remained unaltered. These results suggest that TNF is not critical for the release of BPI from neutrophils during experimental endotoxemia or clinical sepsis.
CD28 expression is not essential for positive and negative selection of thymocytes or peripheral T cell tolerance.
Authors: Walunas T L , Sperling A I , Khattri R , Thompson C B , Bluestone J A 
Published: December 2022

Abstract
Thymocyte development requires positive selection of clones that can recognize Ag presented by MHC molecules and negative selection of clones that are self-reactive. However, the costimulatory signals required for negative selection and cell death, or positive selection and the transition to the peripheral lymphoid system, are not well understood. Many molecular interactions that are important for T cell activation have also been found to play a role in thymocyte development. The importance of the CD28/B7 interaction in the activation of mature T cells and recent observations that CD28 may play a role negative selection of developing CD4+CD8+ thymocytes suggest that CD28 may also be involved in development and maintenance of T cell tolerance. CD28-deficient mice were crossed to alpha beta and gamma delta TCR transgenic as well as H-2k Mlsc-bearing animals and were used to address the role of CD28 in positive and negative selection of developing T cells. The CD28-deficient animals demonstrated no obvious deficiency in either positive or negative selection of developing thymocytes. However, when mixed bone marrow chimeras were created with cells derived from both CD28-deficient and wild-type mice, the CD28+ T cells had a selective advantage over the CD28-deficient T cells. Therefore, it appears that CD28, although not essential for the selection of T cells during development, may allow for additional signals that increase the efficiency of selection and/or expansion of peripheral T cell populations.
Endogenous IL-12 is necessary for rejection of P815 tumor variants in vivo.
Authors: Fallarino F , Uyttenhove C , Boon T , Gajewski T F 
Published: December 2022

Abstract
Although murine tumor cells have been transfected to express a multitude of different cytokines and shown to be rejected in vivo, it is unclear which of these factors might be useful to facilitate tumor Ag immunization schemes. A study of the normal immune mechanisms involved in tumor rejection when it naturally occurs should reveal critical signals for generation of antitumor CTL in vivo. The highly transfectable variant of P815, P1.HTR, was found to be rejected in the hind footpads by approximately one-third of syngeneic DBA/2 mice. Analysis of draining popliteal lymph nodes revealed a large influx of CD4+ and CD8+ T lymphocytes in all mice, indicating that a failure to reject was not due to the complete absence of an inflammatory response. However, although IL-2 and IL-3 were produced by lymph node cells from all mice, only approximately one-third generated a high IFN-gamma response. IL-4 was not detected. To explore a role for IL-12 in the induction of the IFN-gamma-producing phenotype, a histidine-tagged IL-12 fusion protein was expressed in mammalian cells and purified by nickel-chelate chromatography, and a rabbit antiserum was produced. Neutralization of IL-12 in vivo eliminated the high IFN-gamma response and prevented rejection of P1.HTR tumors and also of a more immunogenic tum- variant of P815, P198. Conversely, exogenous IL-12 delivered early during challenge with P1.HTR cells induced high IFN-gamma production and resulted in tumor rejection in most mice. Therefore, endogenous IL-12 is vital for the rejection of these tumors when it naturally occurs, supporting a role for exogenous administration of this cytokine to favor a Th1-like phenotype in the immunotherapy of cancer.
Expression and growth-promoting function of the IL-8 receptor beta in human melanoma cells.
Authors: Norgauer J , Metzner B , Schraufstätter I 
Published: December 2022

Abstract
The chemokine GRO alpha is an autocrine growth factor for melanoma cells. Although GRO alpha has been identified as a high affinity ligand for the IL-8 receptor beta (IL-8R beta) in recombinant systems, the receptor mediating its action in melanoma cells has been a matter of debate. Here, we show by reverse transcription and PCR expression of IL-8R beta, mRNA transcripts in different melanoma cell lines and in normal human melanocytes. To characterize the role of the IL-8R beta in melanoma cells, antiserum was raised in rabbits against a fusion protein containing the NH2-terminal portion of the receptor. Its specificity was shown by flow cytometry with IL-8R beta-transfected HL60 cells. A specific epitope could be mapped with IL-8R beta mutants to the peptide sequence between ASP-4 and ASP-14 of this receptor. Binding studies with [125I]GRO alpha in IL-8R beta transfectants indicated ligand antagonistic properties of this Ab. Expression of IL-8R beta protein at the cell surface of various melanoma cell lines could be shown by flow cytometry with F(ab')2 fragments of the IL-8R beta antiserum. Moreover, anti-IL-8R beta Ab partially blocked specific binding of [125I]GRO alpha in various melanoma cell lines. Addition of F(ab')2 fragments of the IL-8R beta antiserum or of neutralizing anti-GRO alpha mAb to different melanoma cell lines identified this GRO alpha-IL-8R beta interaction as a major component required for serum-independent melanoma cell growth.
Local inflammation caused by a monoclonal antibody that blocks the function of the rat membrane inhibitor of C3 convertase.
Authors: Nishikawa K , Matsuo S , Okada N , Morgan B P , Okada H 
Published: December 2022

Abstract
The participation of membrane inhibitors in C-mediated inflammation in vivo was analyzed in rats with the use of mAbs against membrane inhibitors of C. 512Ag inhibits C3 convertase of homologous rat C and rat CD59 prevents the formation of homologous membrane attack complexes. The histologic distributions of 512Ag and CD59 in rat skin were essentially the same. However, although intracutaneous administration of mAb against 512Ag (anti-512Ag) in the form of F(ab')2 induced a remarkable inflammatory response visualized by exudation of Evans blue that had been previously injected i.v., the mAb against CD59 caused no inflammatory exudate. Furthermore, anti-512Ag F(ab')2 caused deposition of C3 followed by intense polymorphonuclear leukocyte infiltration and hemorrhage at the injection sites within 24 h. This reaction was completely abrogated by depletion of C. Therefore, spontaneous C activation on self cell membranes requires amplification at the C3 convertase step, which is restricted by membrane inhibitors such as 512Ag, thus preventing inflammation. A type II allergic response might preferentially occur at sites that exhibit an impairment of membrane inhibitor(s) of C3 convertase. However, although depletion of leukocytes by preadministration of cyclophosphamide did not reduce C3 deposition by anti-512Ag. Evans blue exudation was appreciably reduced, indicating that infiltrated leukocytes play a role in enhancing and prolonging inflammation initiated by local C activation.
T cell activation is regulated by voltage-dependent and calcium-activated potassium channels.
Authors: Rader R K , Kahn L E , Anderson G D , Martin C L , Chinn K S , Gregory S A 
Published: December 2022

Abstract
Membrane potential (Vm) is tightly controlled in T cells through the regulated flux of ions across the plasma membrane. To investigate the functional role of voltage-dependent (Kv) and calcium-activated (KCa) potassium channels in T cell activation, we compared the effects of two K+ channel blockers, namely kaliotoxin (KTX) and charybdotoxin (CHTX), on Vm, calcium influx, and cell proliferation. KTX potently inhibited Kv (ID50 = 3 nM) but not KCa (ID50 = 5 microM) currents in T cells. Resting T cells exposed to KTX (300 nM) depolarized from -56 mV to -50 mV. KTX had no effect on the transient membrane hyperpolarization that characteristically follows receptor-mediated T cell stimulation. However, T cells stimulated in the presence of KTX subsequently depolarized to -40 mV. KTX also reduced the steady state intracellular free calcium concentration ([Ca2+]i) in stimulated cells by 19% and inhibited T cell proliferation by 35%. CHTX potently inhibited both Kv and KCa currents (ID50 = approximately 1 nM). CHTX (300 nM) depolarized resting T cells to -48 mV, equivalent to the effect observed for KTX. In stimulated T cells, 300 nM CHTX completely blocked the induced hyperpolarization and subsequently depolarized the cells to -21 mV. These effects were associated with a 45% reduction in peak [Ca2+]i, a 60% decrease in steady state [Ca2+]i, and 63% inhibition of T cell proliferation. These results suggest that both Kv and KCa conductances contribute to the underlying mechanisms of T cell activation.
A zinc finger protein that represses transcription of the human MHC class II gene, DPA.
Authors: Scholl T , Stevens M B , Mahanta S , Strominger J L 
Published: December 2022

Abstract
The proximal promoters of all MHC class II genes contain a sequence element, the 19-bp X box, that is conserved in both sequence and position. Extensive analysis using a wide variety of approaches has demonstrated that the integrity of the X box is essential for transcription initiation from all class II genes studied. However, the X box is now recognized to contain two subregions, termed X1 and X2. Radiolabeled oligonucleotides corresponding to the X2 box of the MHC class II genes DPA and DQB were used to screen B cell and T cell expression libraries. A novel cDNA, termed XBR (X box repressor), encoding a putative zinc finger protein that binds specifically to the DPA X2 box was isolated from a human T cell line. The XBR gene encodes a 7-kb message that is ubiquitously transcribed, although at higher levels in tissues of the lymphocytic compartment. Southern blots indicate that this gene is single copy in primates and contains regions that are highly divergent in other species. Overexpression of XBR in a B cell line resulted in a dramatic reduction of transcription from a reporter gene construct driven by the DPA promoter, but not from similar constructs with mutations in the X2 box. Similarly, overexpression of XBR reduced induction of reporter gene activity driven from the DPA promoter in HeLa cells treated with IFN-gamma. XBR may, therefore, mediate transcriptional repression, thus preventing inappropriate MHC class II expression. XBR function may in part explain the dominant trans-acting repression of MHC class II expression reported in cell fusion experiments.
T cell-derived IL-3 induces the production of IL-4 by non-B, non-T cells to amplify the Th2-cytokine response to a non-parasite antigen in Schistosoma mansoni-infected mice.
Authors: Kullberg M C , Berzofsky J A , Jankovic D L , Barbieri S , Williams M E , Perlmann P , Sher A , Troye-Blomberg M 
Published: December 2022

Abstract
We describe a novel amplification mechanism underlying the increased early IL-4 production observed in Schistosoma mansoni-infected mice in response to a non-parasite Ag, sperm whale myoglobin (SwMb). Earlier studies have shown that splenic Fc epsilon R+ non-B, non-T (NBNT) cells from schistosome-infected mice secrete IL-4 after stimulation with parasite Ag. We now demonstrate that purified NBNT cells from SwMb-immunized S. mansoni-infected mice do not respond directly to SwMb, but produce IL-4 in response to IL-3. Accordingly, we show that the early SwMb-specific IL-4 response of spleen cells (SC) from immunized infected mice is dependent on IL-3 and on CD4+ T cells. Thus, most of the early SwMb-induced IL-4 from SC of infected mice appears to be produced by NBNT cells triggered by IL-3 synthesized by SwMb-specific CD4+ T cells. IL-3-induced IL-4 production was also observed in purified NBNT cells from immunized uninfected mice, but the frequency and/or IL-4-producing capacity of splenic IL-3-responsive cells was found to be 8 to 16 times higher in immunized infected animals. IL-4 production by purified CD4+ cells from immunized infected mice was also seen after SwMb stimulation, but this response showed slower kinetics than those of total SC, was IL-3-independent, and on average threefold greater than that by CD4+ cells from immunized uninfected controls. Thus, increased SwMb-induced IL-4 production in immunized S. mansoni-infected mice results from direct synthesis by CD4+ T cells, as well as their stimulation via IL-3 of an expanded population of NBNT cells. The latter pathway may serve as an amplification loop for Th2-cytokine responses.
CTL epitope generation is tightly linked to cellular proteolysis of a Listeria monocytogenes antigen.
Authors: Sijts A J , Villanueva M S , Pamer E G 
Published: December 2022

Abstract
Listeria monocytogenes is a pathogenic intracellular bacterium that secretes proteins into the cytosol of host cells. A major secreted protein, p60, is processed by the host cell into the nonamer peptides p60 217-225 and p60 449-457, which are presented to CTL by H-2Kd MHC class I molecules. Herein, we use two membrane permeable peptide aldehyde protease inhibitors, LLnL and Z-LLF, to inhibit cytosolic proteolysis in L. monocytogenes-infected cells. These inhibitors, which have been shown to inhibit proteasomes, completely abrogate cytosolic p60 degradation. The effect of LLnL and Z-LLF on p60 epitope generation was determined by acid-eluting, HPLC-purifying, and quantifying p60 217-225 and p60 449-457 from infected cells. We show a direct linkage between p60 degradation and epitope generation. However, the two inhibitors have quantitatively different effects on the generation of the two epitopes. Our findings implicate proteasomes in the earliest stages of Ag degradation and suggest that different CTL epitopes can be generated by distinct proteolytic processes.
Dermal microvascular endothelial cells express CD32 receptors in vivo and in vitro.
Authors: Gröger M , Sarmay G , Fiebiger E , Wolff K , Petzelbauer P 
Published: December 2022

Abstract
Immune complexes are thought to be the major cause of cutaneous necrotizing vasculitis, but the mechanism of immune complex targeting to specific vessels is largely unknown. In myelomonocytic cells, immune complex binding and receptor-mediated endocytosis are mediated by Fc gamma R. We asked whether dermal microvascular endothelial cells (DMEC) express Fc gamma Rs. In cryostat sections of normal human skin, mAb IV.3 or AT10, both recognizing CD32 (Fc gamma RII), localizes to the luminal surface of DMEC of the superficial but not of the deep vascular plexus. All DMEC do not express CD16 (Fc gamma RIII) or CD64 (Fc gamma RI) molecules. Adult skin-derived DMEC in culture express CD32 (Fc gamma RII) molecules, as measured by FACS, but are negative for CD16 or CD64. HUVEC, tested for comparison, do not express CD16, 32, or 64 proteins. By reverse-transcriptase PCR and subsequent Southern blot analysis, the isoform of the CD32 molecule expressed on DMEC is determined as Fc gamma RIIa. HUVEC do not contain Fc gamma RIIa or Fc gamma RIIb mRNA. In DMEC, Fc gamma RIIa cross-linking results in immediate intracellular free Ca2+ ([Ca2+]i) concentration fluxes and in rapid internalization of the occupied receptors. We conclude that DMEC are equipped with fully functional Fc gamma RIIa molecules.