bluuebunny/crossref_metadata_2025_split huggingface dataset:
Opposing effects of glucocorticoids on the rate of apoptosis in neutrophilic and eosinophilic granulocytes.
Authors: Meagher L C , Cousin J M , Seckl J R , Haslett C 
Published: December 2022

Abstract
Eosinophils and neutrophils are closely related, terminally differentiated cells that in vitro undergo constitutive cell death by apoptosis. The onset of apoptosis in both cell types can be delayed by hemopoietins and inflammatory mediators. Although there have been a number of reports demonstrating that glucocorticoids (in particular dexamethasone) antagonize the eosinophil life-prolonging effects of hemopoietins, direct effects of dexamethasone on eosinophil apoptosis have not been documented. In this study we examined the direct effects of glucocorticoids on eosinophil and neutrophil apoptosis in light of their common therapeutic use as anti-inflammatory and anti-allergic/hypereosinophilic agents. We found that treatment with dexamethasone induced eosinophil apoptosis. In contrast, dexamethasone was a potent inhibitor of neutrophil apoptosis. The effect of dexamethasone on both cell types was mediated through the glucocorticoid receptor, i.e., it was abolished by the glucocorticoid receptor antagonist RU38486. This is the first description of an agent that promotes eosinophil apoptosis while inhibiting neutrophil apoptosis, and thus presents a novel approach to the study of control of apoptosis in these closely related cell types as well as increases our understanding of the clinical action of glucocorticoids in inflammation.
IFN-gamma up-regulates expression of the complement components C3 and C4 by stabilization of mRNA.
Authors: Mitchell T J , Naughton M , Norsworthy P , Davies K A , Walport M J , Morley B J 
Published: December 2022

Abstract
We investigated the mechanisms underlying the regulation of complement genes C3 and C4 by IFN-gamma. IFN-gamma (500 U/ml, 24 h incubation) increased steady state mRNA levels for both C3 and C4 in three different cell types (Hep G2, U937, and primary fibroblasts). The response to IFN-gamma in Hep G2 cells was time and dose dependent. At all doses of IFN-gamma and at all incubation times, the transcription rate for these two genes, determined by nuclear run-on assays, was reduced (0.3 +/- 0.1; unstimulated rate = 1.00). The t1/2 of mRNA for C3 and C4 in unstimulated cells was 1.8 +/- 0.3 and 2.2 +/- 0.2 h, respectively. After high-dose IFN-gamma stimulation, both C3 and C4 mRNA levels remained at 100% with respect to baseline at 5 h, but after 12 h, levels fell to 13 +/- 2% (C3) and 8 +/- 3% (C4) of baseline values, giving a half-life for these mRNA species of between 5 and 12 h. IFN-gamma stimulation increased C3 and C4 protein synthesis measured at 24 h. We suggest that it is the increase in mRNA stability that is the major effector mechanism by which IFN-gamma regulates C3 and C4 gene expression.
Eosinophil-fibroblast interactions. Granule major basic protein interacts with IL-1 and transforming growth factor-beta in the stimulation of lung fibroblast IL-6-type cytokine production.
Authors: Rochester C L , Ackerman S J , Zheng T , Elias J A 
Published: December 2022

Abstract
To test the hypothesis that eosinophil major basic protein (MBP) is an important regulator of fibroblast effector function, we characterized the effects of MBP on human lung fibroblast production of the IL-6-type cytokines, IL-6, IL-11, and leukemia inhibitory factor. Unstimulated fibroblasts did not produce substantial quantities of these cytokines, while IL-1 and TGF-beta(1) stimulated these cytokines in a potent fashion. MBP at doses &lt; or = 44 micrograms/ml did not stimulate IL-6-type cytokine production. It did, however, interact in a synergistic, dose- and time-dependent fashion with rIL-1-alpha and TGF-beta(1) to further increase IL-6-type cytokine elaboration. These MBP-induced increases in cytokine production were associated with proportionate alterations in mRNA accumulation. In contrast, eosinophil-derived neurotoxin did not regulate fibroblast cytokine production, and MBP did not augment fibroblast granulocyte-macrophage-CSF, or type I collagen production, or fibroblast proliferation in this culture system. The effects of MBP could not be attributed to cell cytotoxicity or contaminants in the MBP preparations. They were, however, at least partially charge mediated, since heparin abolished the effects of MBP on IL-1-stimulated cells, and the surrogate cationic molecule poly-L-arginine mimicked the stimulatory effects of MBP on fibroblast IL-6-type cytokine elaboration. These studies demonstrate that MBP interacts in a synergistic fashion with rIL-1-alpha or TGF-beta(1) to further augment fibroblast IL-6-type cytokine production. They also demonstrate that this stimulation is pretranslationally mediated and due, in part, to the cationic nature of the MBP molecule. MBP regulation of fibroblast cytokine production may play an important role in the pathogenesis of eosinophilic disorders of the airway or other organs.
Enhancement of delayed-type hypersensitivity to sheep red blood cells in mice by granulocyte colony-stimulating factor administration at the elicitation phase.
Authors: Terashita M , Kudo C , Yamashita T , Gresser I , Sendo F 
Published: December 2022

Abstract
We previously demonstrated that selective depletion of polymorphonuclear neutrophils by a mAb inhibits both the priming and effector phases of delayed-type hypersensitivity (DTH) to SRBC. To better understand the role of polymorphonuclear neutrophils in DTH, we examined the effect of granulocyte CSF (G-CSF) on DTH to SRBC in mice. G-CSF administered at the elicitation phase enhanced a DTH response that was weak in control G-CSF-untreated mice. This treatment also augmented mononuclear leukocyte recruitment in DTH in these mice. However, G-CSF administration failed to augment priming of DTH to SRBC under any conditions examined.
Sublytic complement attack induces cell cycle in oligodendrocytes.
Authors: Rus H G , Niculescu F , Shin M L 
Published: December 2022

Abstract
Sublytic complement attack on oligodendrocytes (OLG) by activation of terminal complement complexes (TCC) selectively enhances the decay of myelin protein mRNAs. We have investigated whether TCC also stimulate differentiated OLG to enter the cell cycle and whether the cell cycle induction is related to the oncogene expression. Complement activation and TCC assembly induced expression of c-jun, JunD, and c-fos mRNAs, increased AP-1 DNA-binding activity within 1 h, and increased [3H]thymidine uptake. The c-jun NH2-terminal kinase activity was increased to the maximum level 20 min after TCC assembly. The increase in thymidine uptake was inhibited by pretreatment of OLG with antisense c-jun oligonucleotides. Studies on cyclin-dependent kinase (cdk) activation revealed that complement increased cyclin-dependent cell cycle associated kinase-2 activity in G1, while cdk2 and cdk4 showed low activity during G1 progression. However, the activity of cdk4 complexed with cyclin D2 showed a marked increase in G1/S transition. Our data provide evidence that sublytic TCC stimulate OLG to enter the cell cycle by induction of c-jun through activation of the c-jun NH2-terminal kinase pathway. In addition, sublytic TCC assembly significantly reduced the number of OLG undergoing apoptotic cell death, which occurs spontaneously in defined medium. These changes together with enhanced degradation of myelin protein mRNA may represent a mechanism for differentiated primary OLG to respond to limited complement activation in inflammation.
Down-regulation of secretion of human complement component C2 by the product of an alternatively spliced C2 messenger RNA.
Authors: Tsukamoto H , Tousson A , Marchase R B , Volanakis J E 
Published: December 2022

Abstract
We have previously described alternatively spliced transcripts of the human C2 gene. Among those, C2delta(17), in which exon 17 has been spliced out, encodes a polypeptide that contains the C4b binding and the CIs cleavage sites of C2, but lacks the serine protease active center. To study the possible function of this variant, we constructed C2delta(17) cDNA by deletional mutagenesis and expressed it transiently in COS cells. Transfected COS cells secreted only trace amounts of the C2delta(17) polypeptide, which had no detectable hemolytic activity and could not be cleaved by CIs. Pulse-chase experiments using [35S]methionine demonstrated that the majority of the 88-kDa C2delta(17) remained intracellular. Control wild-type (wt) C2 in the intracellular compartment consisted of two bands of 93 and 99 kDa, the latter corresponding to mature secreted C2. Intracellular C2delta(17) and only the 93-kDa wt C2 were sensitive to endoglycosidase H, a marker for transport from the endoplasmic reticulum (ER) to the Golgi. Experiments using brefeldin A and double label immunofluorescence staining indicated that C2delta(17) exhibited a typical ER distribution pattern, while wt C2 accumulated in the ER-Golgi intermediate compartment. Secretion of C2 by COS cells cotransfected with wt C2 and C2delta(17) cDNA was significantly decreased compared with that by cells transfected with wt C2 alone. These combined results indicate that C2delta(17) is retained in the ER probably because it is incorrectly folded and that it could down-regulate the expression of the wt C2 gene.
Analysis of the sugar specificity and molecular location of the beta-glucan-binding lectin site of complement receptor type 3 (CD11b/CD18).
Authors: Thornton B P , Vĕtvicka V , Pitman M , Goldman R C , Ross G D 
Published: December 2022

Abstract
Zymosan, the cell wall from Saccharomyces cerevisiae, was reported to be a macrophage activator through its beta-glucan over 30 yr ago. Nevertheless, the identity of the beta-glucan receptor has been controversial. This study showed that the alpha M beta 2-integrin, CR3 (Mac-1, CD11b/CD18) served as the beta-glucan receptor through one or more lectin sites located outside of the CD11b I-domain that contains the binding sites for iC3b, ICAM-1, and fibrinogen. Sugar specificity, analyzed with FITC-labeled soluble polysaccharides and flow cytometry, showed CR3-specific staining with several pure beta-glucans but not with alpha-mannan. However, a 10-kDa soluble zymosan polysaccharide (SZP) with high affinity (6.7 x 10(-8) M) for CR3 consisted largely of mannose and approximately 5% glucose. Binding of either SZP-FITC or beta-glucan-FITC to CR3 was blocked not only by pure beta-glucans from yeast, mushroom, seaweed, or barley, but also by N-acetyl-D-glucosamine (NADG), alpha- or beta-methylmannoside, and alpha- or beta-methyl-glucoside. SZP-FITC and beta-glucan-FITC stained all leukocyte types similarly to anti-CR3-FITC, and polysaccharide-FITC staining was inhibited &gt; or = 95% by unlabeled anti-CR3. SZP-FITC staining of cells expressing recombinant chimeras between CR3 and CR4 (p150,95, CD11c/CD18) suggested that both the divalent cation-binding region of CD11b and the region C-terminal to it may regulate binding of polysaccharides to CR3. Unlabeled SZP or beta-glucan also blocked CR3 staining by 11 mAb to C-terminal domain epitopes of CD11b but had no effect on staining by mAb directed to the I-domain. In conclusion, CR3 serves as the leukocyte beta-glucan receptor through a cation-independent lectin site located C-terminal to the I-domain of CD11b. Its sugar specificity is broader than originally appreciated, allowing it to react with certain polysaccharides containing mannose or NADG, as well as glucose.
Both Sm and DNA are selecting antigens in the anti-Sm B cell response in autoimmune MRL/lpr mice.
Authors: Retter M W , Cohen P L , Eisenberg R A , Clarke S H 
Published: December 2022

Abstract
More than half of the anti-Sm hybridomas isolated from MRL/Mp-lpr/lpr (MRL/lpr) mice produce Abs that also bind ssDNA, and half of these bind dsDNA. Intraclonal comparisons indicate that DNA is a selecting Ag for at least some dual-binding clones. To determine whether Sm itself is a selecting Ag for anti-Sm, we have identified the somatic mutations within the expressed VH and V kappa genes of eight anti-Sm hybridomas, six of which do not bind DNA. We find these V genes have between 0 and 12 somatic mutations each, and that four hybridomas possess a higher number of heavy or light chain CDR replacement (R) mutations than expected by chance, suggesting that these anti-Sm-producing B cells have undergone Ag selection. To demonstrate directly the effect of somatic mutation on Sm binding, we have engineered the unmutated counterpart of Ab 2-12, an Sm-specific hybridoma Ab with a nonrandom distribution of V kappa CDR R mutations, and compared its ability to bind Sm and ssDNA with that of the originally isolated 2-12 Ab. We find that the unmutated Ab has a much lower avidity for Sm than the mutant, but, unlike the mutant, it binds ssDNA. We conclude that Sm can drive clonal expansion in the anti-Sm response, and that Sm-only binding B cells can arise from Sm/DNA dual-binding B cell clonal precursors. These data also suggest that dual binding is not necessary to sustain clonal expansion. Thus, this response is unique in that it can be driven by either of two Ags.
Cytokine gene expression in islets and thyroids of BB rats. IFN-gamma and IL-12p40 mRNA increase with age in both diabetic and insulin-treated nondiabetic BB rats.
Authors: Zipris D , Greiner D L , Malkani S , Whalen B , Mordes J P , Rossini A A 
Published: December 2022

Abstract
Inflammatory cytokines, particularly those produced by Th1 type lymphocytes, are hypothesized to play a major role in the pathogenesis of autoimmune diseases. The present studies investigated this hypothesis in the BB rat. Diabetes-prone (DP) BB rats develop spontaneous hyperglycemia and thyroiditis. Coisogenic diabetes-resistant (DR) BB rats do not develop either disorder spontaneously, but both diseases are induced by depletion of RT6+ T cells. Reverse transcriptase-PCR was used to measure mRNA encoding type 1 and type 2 cytokines. In both DP and RT6-depleted DR rats, IFN-gamma mRNA was present in islets before and during disease onset. IL-2 and IL-4 mRNAs were minimal or undetectable in infiltrated islets but present in activated peripheral T cells. IL-10 mRNA was present at low abundance in infiltrating T cells. These observations suggested a Th1 type inflammatory response, and consistent with this interpretation, we observed that mRNA encoding the p40 chain of IL-12 was also present before and during disease onset. Similar cytokine mRNA profiles were observed in the thyroids of RT6-depleted DR rats and in the islets of DP rats treated with prophylactic parenteral insulin to prevent diabetes. We conclude that IFN-gamma and IL-12 may play a major role in the expression of insulitis and thyroiditis in the BB rat, that Th1 lymphocytes may predominate over Th2 lymphocytes in these inflammatory lesions, and that prevention of diabetes by insulin is not associated with an alteration in the cytokine gene profile of islet infiltrating cells.
Target-induced inactivation and cell death by apoptosis in a subset of human NK cells.
Authors: Jewett A , Bonavida B 
Published: December 2022

Abstract
Interaction of sensitive target cells with NK cells results in both positive and negative signaling. Positive signaling results in the induction of NK cytotoxicity and sensitization for IL-2-mediated proliferation and secretion of cytokines. Negative signaling prevents the NK cells from recycling for cytotoxicity. Functional inactivation is restricted to the NK-target conjugate subset sparing the nonconjugating free NK subset. The mechanism of target-induced inactivation of NK cells was examined in cell-sorted and purified conjugates. The conjugates were subdivided into two fractions; in one fraction the NK cells were dissociated from the target (NKDC), and in the other fraction the conjugates were not disturbed (NKC). After coculture overnight with IL-2, the cytotoxic function of NKC was not augmented although a subpopulation proliferated and secreted TNF-alpha and IFN-gamma into the supernatant. In contrast, NKDC cytotoxic activity was enhanced by IL-2, but proliferated poorly and did not secrete TNF-alpha or IFN-gamma following IL-2 activation. The phenotype of the inactive NKC was found to be CD16dim/- CD692+ CD11b2+. Target-mediated inactivation correlated with target cell sensitivity to NK cytotoxicity. Furthermore, a significant fraction of NK cells in the NKC was programmed for cell death by apoptosis. Altogether, these results demonstrate that sensitive targets inactivate NK cells for cytotoxicity resulting in loss of NK cells. Furthermore, the results suggest that signaling for cytotoxic function by target cells is not linked to signaling for proliferation and secretion of cytokines by NK cells.
An inducible lymphocyte nuclear Ca2+/Mg(2+)-dependent endonuclease associated with apoptosis.
Authors: Khodarev N N , Ashwell J D 
Published: December 2022

Abstract
Apoptotic cell death is typically accompanied by internucleosomal chromatin fragmentation. Although a number of candidate enzymes have been proposed, there is as yet no direct evidence for the involvement of any particular endonuclease in this process. Here we demonstrate the existence of an endonuclease(s) that is up-regulated during apoptotic T cell death. The endonuclease(s) is located in the nucleus, and its activity is increased up to eightfold by a variety of stimuli or conditions that induce apoptosis in T cell hybridomas and thymocytes. Treatments that prevent TCR-mediated apoptosis, such as cyclosporin A or concomitant administration of glucocorticoids, also prevent the induction of enzyme activity. The endonuclease activity is associated with three molecular forms, designated A, B, and C, with apparent M(r) of 49K, 47K, and 45K, respectively, and constitutes the major endonuclease activity in T hybridoma cells. From A exists in resting cells, and its activity is increased threefold after the induction of apoptosis. Forms B and C are absent in resting cells and are induced up to 20-fold after stimuli that lead to apoptosis. All three forms are Ca2+/Mg2+ dependent and are inhibited by Zn2+. This enzyme(s) introduces double strand breaks and single strand nicks into supercoiled plasmid DNA, demonstrating the mode of DNA fragmentation characteristic of products of apoptotic chromatin degradation. The enzyme(s) produces DNA fragments with 5'-P and 3'-OH terminals, also consistent with apoptotic chromatin degradation. Finally, enzyme solubilized from cells activated to die cleaves chromatin in nuclei isolated from unstimulated T hybridoma cells, yielding the classic DNA ladder. Because of its biologic properties, we named this enzyme(s) inducible lymphocyte Ca2+/Mg(2+)-dependent endonuclease, or ILCME. Because inducible lymphocyte Ca2+/Mg(2+)-dependent endonuclease possesses the key features predicted for an apoptosis-specific enzyme, it is a new candidate for an enzyme(s) that participates in DNA cleavage in apoptotic T cells.
Thymus-leukemia antigen interacts with T cells and self-peptides.
Authors: Sharma P , Joyce S , Chorney K A , Griffith J W , Bonneau R H , Wilson F D , Johnson C A , Flavell R A , Chorney M J 
Published: December 2022

Abstract
The functional role of the class Ib thymus-leukemia (TL) Ag expressed within the thymic cortex and intestinal mucosa of the mouse remains unknown. In an approach to elucidate the potential functionality of TL, we developed transgenic mice that ectopically express the H-2T18d gene product on essentially all nucleated cells through the control of a heterologous H-2Kb gene promoter. Transgenic mice demonstrated an increase in the number of CD4+ lymphocytes within the thymus and lymph nodes; these cells displayed an altered T cell receptor repertoire possibly suggesting a role for the ectopically expressed TL protein. The TL protein additionally displayed the characteristics of a bona fide transplantation Ag, because skin grafts from transgenic animals onto MHC- and minor histocompatibility Ag-matched nontransgenic recipient mice resulted in a rapid and vigorous immunologic rejection of the allograft. In MLR studies, transgenic stimulator cells induced the proliferation of responders to a level intermediate between genetically identical and H-2-disparate responder-stimulator combinations. The TL protein was also capable of stimulating cytotoxic T lymphocytes, thereby resulting in specific lysis of TL+ target cells. Further data demonstrated that the TL protein assembles with peptides that are modified at the amino terminus, and that TL retains these molecules at the cell surface. Together, these data suggest that H-2T18d is capable of interacting with T cells via a bound peptide. These data further support the possibility that TL may subserve a specialized function within the immunologic system.
Immature T cells in peripheral lymphoid organs of recombinase-activating gene-1/-2-deficient mice. Thymus dependence and responsiveness to anti-CD3 epsilon antibody.
Authors: Falk I , Potocnik A J , Barthlott T , Levelt C N , Eichmann K 
Published: December 2022

Abstract
Thymocytes of mice deficient in the recombinase-activating gene (RAG)-1 or RAG-2 cannot express and receive signals through the pre-TCR. As a result, thymocyte development in these mice terminates at the CD4/8 double negative (DN), IL-2R-alpha-positive stage. Nevertheless, RAG-deficient DN thymocytes express functional CD3 complexes and can therefore be induced by anti-CD3 epsilon mAb to mature to the CD4+8+ double positive stage. In the present paper we demonstrate that the peripheral lymphoid organs (lymph nodes, spleen) and peripheral blood of RAG-deficient mice harbor an immature T cell population which, similar to RAG-deficient DN thymocytes, contains high levels of cytoplasmic CD3 epsilon and responds to anti-CD3 epsilon mAb in vivo. With respect to surface phenotype (Thy1.2+, PgP-1+, HSA+, Fc gamma RII/III-, IL-2R-alpha-, c-kit-), these cells are similar to intermediate stage RAG-deficient DN thymocytes. Moreover, they express mRNA for pre-TCR-alpha and for the nondeleted RAG. Following injection of anti-CD3 epsilon mAb, these cells proliferate, down-regulate heat stable Ag and PgP-1, and partially differentiate to CD4+ and CD8+ double positive and single positive cells. The induced population displays a mixed phenotype, between that of immature thymocytes and lymph node T cells in normal mice. Induction is successful in thymectomized RAG-deficient mice, suggesting that it occurs in the periphery. However, after thymectomy, inducible cells disappear with an approximate half-life of 10 to 14 days. We suggest that DN thymocytes can emigrate and repopulate peripheral lymphoid organs of RAG-deficient mice. These cells respond to CD3 signaling by aberrant maturation, possibly due to the inappropriate microenvironment of peripheral lymphoid organs.
Stat1 implication in the immune response to superantigens in vivo.
Authors: Gimeno R , Codony-Servat J , Plana M , Rodriguez-Sanchez J L , Juarez C 
Published: December 2022

Abstract
We analyzed the activation and changes in the protein level of STAT1 as a consequence of in vivo treatment with superantigens. Ninety minutes after i.p. injection of the staphylococcal enterotoxin B (SEB), a complex containing STAT1 that was able to specifically bind to DNA containing GAS-like sequences was activated in mouse splenocytes. This complex had the same characteristics as that induced by IFN-gamma in several in vitro systems. Activation of the complex was inhibited by cyclosporin A, and Abs against IFN-gamma severely decreased the amount of complex detected. When splenocytes were analyzed 24 h after SEB treatment, a high increase in the amount of the STAT1 isoforms, STAT91 and STAT84, was observed by Western analysis, but binding to GAS-like sequences was clearly decreased when compared with analysis at 90 min. Nevertheless, when SEB was injected a second time 24 h after the first injection, the binding of STAT1 to GAS-like sequences had risen again. This approach corroborates the implication of IFN-gamma in the response to superantigens in vivo and shows the relevance of analysis of transcription factors in defining the molecular events involved in the immune response.