bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of IL-18 (IFN-gamma-inducing factor) gene expression.
Authors: Tone M , Thompson S A , Tone Y , Fairchild P J , Waldmann H 
Published: January 2023

Abstract
IL-18 (also known as IFN-gamma-inducing factor), although structurally unrelated to IL-12, shares with it the role of activating NK cells and polarizing T cells toward Th1 cell function. To understand how the IL-18 gene (and consequently Th1 function) is regulated, we have determined the gene structure and investigated the mechanisms of transcriptional control and cell type expression. The mouse IL-18 gene comprises seven exons distributed over 26 kb. Exons 1 and 2 of this gene are 5'-noncoding exons. Promoter activity was detected upstream of these noncoding exons in two distinct regions. Both promoters are TATA-less and not G+C rich. The promoter activity located upstream of exon 2 was shown to act constitutively, while the activity located upstream of exon 1 was up-regulated in activated macrophage and T cell lines. IL-18 gene expression may be regulated in a wide range of cell types by the activities of these two distinct promoters. IL-18 is known to be synthesized as a precursor, pro-IL-18, and its maturation is controlled by IL-1beta-converting enzyme (ICE). We observed concordant expression of IL-18 and ICE mRNAs in a wide range of cell types, unlike the more restricted expression of IL-12 p40 mRNA. The widespread IL-18 mRNA distribution and the special relationship with ICE lead us to the hypothesis that IL-18 expression may be coupled with apoptotic processes involving activation of ICE or ICE-like proteinase.
Calcium-dependent neutrophil secretion: characterization and regulation by annexins.
Authors: Rosales J L , Ernst J D 
Published: January 2023

Abstract
To gain direct access to the secretory machinery and study the regulation, mechanisms, and effectors of Ca2+-dependent neutrophil secretion, we developed an efficient and reproducible method of plasma membrane permeabilization using streptolysin O. We confirmed previous studies that permeabilized neutrophils secrete in response to calcium alone, but we also found that the Ca2+ dose-response is biphasic. Secretion is detectable at &lt;1.0 microM Ca2+ and reaches a plateau between 1.0 and 60 to 80 microM. When stimulated with &gt;80 microM Ca2+, secretion is two- to threefold greater than at lower [Ca2+], suggesting that two distinct mechanisms of Ca2+-dependent secretion that differ in their affinity for Ca2+ exist in neutrophils. Although permeabilization allows 100% leak of lactate dehydrogenase, maximum secretion from permeabilized cells is 80% that of f-met-leu-phe-stimulated intact cells, indicating that the essential components of the Ca2+-dependent secretory apparatus are predominantly, if not entirely, membrane bound. Permeabilization causes leakage of 100% of annexins V and VI, but 41% of annexin I and 12% of annexin III are retained. Immunofluorescence microscopy revealed that retained annexins I and III are associated with granule membranes. Addition of soluble annexins I and III to permeabilized cells increased Ca2+-induced secretion up to 15% and 90%, respectively, implying that both annexins participate in this secretory pathway. While annexin V is not required for secretion, it inhibits the low Ca2+-affinity mechanism of secretion.
Inhibition of inducible nitric oxide synthase intensifies injury and functional deterioration in autoimmune interstitial nephritis.
Authors: Gabbai F B , Boggiano C , Peter T , Khang S , Archer C , Gold D P , Kelly C J 
Published: January 2023

Abstract
T lymphocytes are exquisitely sensitive to the antiproliferative effects of nitric oxide. We examined the effects of oral administration of two nitric oxide synthase inhibitors, Nw-nitro-L-arginine methyl ester (L-NAME) and L-N6-(1-iminoethyl)lysine (L-NIL), on the course of T cell-dependent autoimmune interstitial nephritis in Brown Norway rats. Kidneys from rats immunized to produce interstitial nephritis display a net generation of nitric oxide end products. By immunohistochemical staining, the cytokine-inducible nitric oxide synthase (iNOS) is expressed in cortical tubular epithelial cells. Treatment with either inhibitor results in markedly more severe disease following immunization. Animals receiving L-NAME were hypertensive, while those treated with L-NIL, a highly selective inhibitor of iNOS, were not. Evaluation of the expression of IFN-gamma, IL-2, and IL-4 in diseased kidneys by quantitative reverse transcriptase-PCR demonstrated that L-NAME-treated animals displayed significantly augmented levels of IFN-gamma and IL-2 with preserved ratios of IFN-gamma/IL-4 and IL-2/IL-4, while L-NIL-treated animals had augmented levels of IL-2 and IFN-gamma with augmented IFN-gamma/IL-4 and IL-2/IL-4 ratios. Animals treated with L-NAME or L-NIL both had augmented Ag-specific IgG responses. The L-NAME group demonstrated increases in both the IgG2a and IgG1 subtypes, with a constant IgG2a/IgG1 ratio, while the L-NIL group demonstrated an increase in the ratio of the IgG2a/IgG1 response. These Ab and cytokine data suggest that the L-NIL-treated animals had a skewing of their immune response toward a Th1-like response. We conclude that in autoimmune interstitial nephritis, generation of nitric oxide through the iNOS pathway has host-protective effects, and suggest that this may be broadly applicable to T cell-mediated pathologies.
Three domains of SLP-76 are required for its optimal function in a T cell line.
Authors: Musci M A , Motto D G , Ross S E , Fang N , Koretzky G A 
Published: January 2023

Abstract
We and others have shown that overexpression of SLP-76 augments TCR-stimulated IL-2 promoter activity in the Jurkat T cell line. In this report we investigate the signaling mechanisms through which SLP-76 mediates its effect on T cell activation. We show that overexpressed SLP-76 acts downstream of TCR-stimulated protein tyrosine kinases, but does not affect calcium signaling. Overexpression of SLP-76 does, however, augment TCR stimulation of both ERK (extracellular signal-regulated kinase) activity and a reporter construct driven by activating protein-1 binding sites. Structure/function analysis reveals that three distinct regions of SLP-76, each important for protein associations, are required for augmentation of TCR-induced nuclear factor-AT activity. These data suggest that SLP-76 functions as an adapter molecule that requires three unique domains to link proximal TCR signals in T cells.
Characterization of IL-12 receptor beta1 chain (IL-12Rbeta1)-deficient mice: IL-12Rbeta1 is an essential component of the functional mouse IL-12 receptor.
Authors: Wu C , Ferrante J , Gately M K , Magram J 
Published: January 2023

Abstract
Two chains of the IL-12R, IL-12Rbeta1 and IL-12Rbeta2, have recently been cloned. To determine the role of IL-12Rbeta1 in mediating the biologic functions of IL-12 in mice, we have generated IL-12Rbeta1-deficient (IL-12Rbeta1(-/-)) mice by targeted mutation in ES cells. Con A-activated splenocytes from IL-12Rbeta1(+/+) mice displayed both high and low affinity IL-12-binding sites, whereas Con A-activated splenocytes from IL-12Rbeta1(-/-) mice expressed only low affinity IL-12-binding sites. Consistent with the expression of low affinity IL-12-binding sites on IL-12Rbeta1(-/-) lymphoblasts, these cells expressed normal amounts of IL-12Rbeta2 mRNA. Unlike those from IL-12Rbeta1(+/+) mice, Con A-activated splenocytes from IL-12Rbeta1(-/-) mice failed to proliferate or produce IFN-gamma in response to IL-12, even at very high concentrations (67 nM). In contrast, lymphoblasts from both types of mice proliferated equally well to IL-2 or IL-7. Splenocytes from IL-12Rbeta1(-/-) mice also failed to display enhanced NK lytic activity when cultured with IL-12 but responded normally to IL-2. Similar to IL-12 p40-deficient mice, IL-12Rbeta1(-/-) mice were impaired in their ability to produce IFN-gamma in response to endotoxin administration in vivo, and IL-12Rbeta1(-/-) splenocytes were deficient in IFN-gamma secretion when stimulated with either Con A or soluble anti-CD3 mAb in vitro. These results demonstrate that IL-12Rbeta1 is required for mouse T and NK cells to respond to IL-12 and that expression of low affinity IL-12-binding sites, presumably reflecting expression of IL-12Rbeta2, is by itself insufficient to mediate IL-12 responsiveness, even in the presence of very high concentrations of IL-12.
Peptide antigen or superantigen-induced down-regulation of TCRs involves both stimulated and unstimulated receptors.
Authors: Niedergang F , Dautry-Varsat A , Alcover A 
Published: January 2023

Abstract
T cell activation by peptide/MHC complexes, superantigens, or mAbs induces the down-regulation of cell surface TCRs. We addressed the question of whether TCR down-modulation affects only TCRs that had directly interacted with their ligand or whether down-modulation could also affect TCRs that had not interacted with their ligand. To this end, we generated T cells coexpressing equal levels of two different TCRs by transfecting the appropriate cDNAs into cells of the human T cell line, Jurkat. Each set of TCRs can be distinguished by means of anti-Vbeta mAbs and can be stimulated separately with peptide Ag, bacterial superantigens, or mAbs. We found that activation of these cells with each of these stimuli down-modulated not only directly stimulated TCR complexes but also unstimulated ones. Comodulation of stimulated and unstimulated receptors may reflect functional interactions between surface TCRs that could take place during Ag or superantigen recognition by T cells without the need for ligand cross-linking. Consistent with this idea, both stimulated and unstimulated receptors colocalized in patches on the cell surface after activation.
T cell genetic background determines maintenance of IL-12 signaling: effects on BALB/c and B10.D2 T helper cell type 1 phenotype development.
Authors: Güler M L , Jacobson N G , Gubler U , Murphy K M 
Published: January 2023

Abstract
In this report, we examined the molecular basis underlying the genetic difference between BALB/c and B10.D2 T cells for T helper phenotype development in vitro. We found a strain-dependent difference in early maintenance of IL-12 responsiveness by T cells developing in vitro in unmanipulated (neutral) conditions. Thus, when activated without addition of exogenous cytokines or neutralization of endogenous cytokines, B10.D2, but not BALB/c, T cells remain responsive to IL-12 when activated for 7 days. The pattern of IL-12 responsiveness correlated with expression of the IL-12R signaling subunit, IL-12R beta2, and with IL-12-induced STAT4 phosphorylation. When activated under neutral conditions, BALB/c T cells rapidly lose IL-12R beta2 expression, STAT4 phosphorylation, and functional IL-12 responsiveness. More efficient maintenance of IL-12R beta2 expression by B10.D2 T cells activated under neutral conditions may explain the previously observed increase in IFN-gamma production relative to that of BALB/c. This difference could potentially provide greater protection from certain pathogens that do not immediately elicit strong Th1-inducing conditions via activation of the innate immune system.
Differential interaction of nuclear factors with the leukocyte-specific pp52 promoter in B and T cells.
Authors: Omori S A , Smale S , O'Shea-Greenfield A , Wall R 
Published: January 2023

Abstract
The leukocyte-specific, cytoskeleton-binding pp52 (LSP-1, WP-34) protein is widely expressed in multiple leukocyte lineages, including B and T lymphocytes, granulocytes, and macrophages. We previously detected a tissue-specific promoter preceding the exon encoding the N terminus of the pp52 leukocyte protein. Here we describe the functional characterization of this promoter and identification of the factors in B and T cells that regulate its activity. The pp52 promoter contains an initiator specifying the unique 5' terminus of pp52 mRNA, tandem pairs of Ets and SP1 motifs, and a lone C/EBP motif. All these motifs are essential and collectively control transcriptional activity. DNA binding studies and Ab supershift assays revealed that different combinations of factors interact with these motifs in B cells vs T cells. The Ets motifs are preferentially bound by PU-1 in B cell extracts from all stages of development, whereas a different Ets family member reacts with these motifs in T cell extracts. The C/EBP motif is bound by Ig/EBP-1 in pre-B cell and T cell extracts, but is replaced by nuclear factor-IL-6beta or a nuclear factor-IL-6beta-Ig/EBP-1 heterodimer in plasmacytoma cell extracts. Despite its reported role as a negative regulator of transcription, Ig/EBP-1 appears to exert a stimulatory effect on this promoter. These findings reveal the features controlling the pp52 promoter in B and T cells and provide the foundation for determining the regulation of this promoter in other leukocyte lineages.
Human dermal microvascular endothelial cells express the melanocortin receptor type 1 and produce increased levels of IL-8 upon stimulation with alpha-melanocyte-stimulating hormone.
Authors: Hartmeyer M , Scholzen T , Becher E , Bhardwaj R S , Schwarz T , Luger T A 
Published: January 2023

Abstract
Pro-opiomelanocortin (POMC)-derived peptides such as alpha-melanocyte-stimulating hormone (alpha-MSH) recently have been recognized as mediators with potent immunomodulating and anti-inflammatory properties. Their effects are mediated via different protein G-coupled melanocortin (MC) receptors that are capable to bind one or more POMC-derived peptides. Among these receptors, MC-1 is specific for alpha-MSH and adrenocorticotropin. The purpose of the present study was to investigate whether MC receptors are expressed on normal human dermal microvascular endothelial cells (HDMEC) as well as transformed human dermal microvascular endothelial cells (HMEC-1). Using semiquantitative reverse transcriptase-PCR and MC receptor-specific primers, both HDMEC and HMEC-1 were found to express MC-1 constitutively. In addition, MC-1 expression was increased upon stimulation with IL-1beta or alpha-MSH itself. Other known MC receptors were neither detectable in unstimulated nor in IL-1beta- or alpha-MSH-stimulated cells. The binding of alpha-MSH by HMEC-1 was specific and saturable as demonstrated by competitive and saturation-binding studies with 125I-labeled alpha-MSH (Kd: 1.1 nM). To evaluate the physiologic relevance of MC-1 expression, HMEC-1 were treated with various concentrations of alpha-MSH (10(-15)-10(-6) M) and were investigated for their cytokine-producing capacity. Alpha-MSH (10(-10)-10(-8) M) significantly up-regulated IL-8 release and mRNA expression by HMEC-1. In contrast, the production of IL-1 or IL-6 by HMEC-1 was not affected upon treatment with alpha-MSH. These data provide first evidence that HDMEC express functional MC receptors. Therefore, alpha-MSH, which is released in the skin during cutaneous inflammation via inducing chemokines may represent an important signal required for leukocyte-endothelial cell interaction.
Selective conversion of big endothelins to tracheal smooth muscle-constricting 31-amino acid-length endothelins by chymase from human mast cells.
Authors: Nakano A , Kishi F , Minami K , Wakabayashi H , Nakaya Y , Kido H 
Published: January 2023

Abstract
Chymase from human mast cells selectively cleaved big endothelins (ETs) at the Tyr31-Gly32 bond and produced novel trachea-constricting 31-amino acid-length endothelins, ETs(1-31), without any further degradation products. Chymases from other species, such as the enzymes from rat connective tissue and mucosal mast cells, and the other chymotrypsin-like proteases examined degraded big ETs. ETs(1-31) exhibited various contractile potencies as to the rat trachea in comparison with 21-amino acid-length endothelins, ETs(1-21), and big ETs: ET-1(1-21) &gt; ET-1(1-31) &gt; big ET-1; ET-2(1-31) &gt; ET-2(1-21) &gt; or = big ET-2; ET-3(1-21) &gt; or = ET-3(1-31) &gt; or = big ET-3. Among the ETs(1-31), ET-2(1-31) was the most potent constrictor, its potency being similar to that of ET-1(1-21) and stronger than that of ET-2(1-21). The contractile activity of ETs(1-31) may not be the consequence of conversion to the corresponding ETs(1-21) by phosphoramidon-sensitive ET-converting enzymes or other chymotrypsin-type proteases and metalloendopeptidases, because the contractile activity was not inhibited significantly on treatment with inhibitors of these proteases before the addition of ET-1(1-31). Inhibitors of chymotrypsin-type serine proteases, on the contrary, significantly enhanced the contractile activity exhibited by ET-1(1-31) and big ET-1, but not that by ET-1(1-21). These results suggest that protease(s) on the surface of the rat trachea tends to degrade ETs(1-31) and big ETs, and thereby reduces their contractile activity. Taken together, the results suggest that trachea-constricting ETs(1-31) generated by human chymase may play a role in the hyper-responsive airway in allergic inflammation.
Characterization of autoantibodies in pemphigus using antigen-specific enzyme-linked immunosorbent assays with baculovirus-expressed recombinant desmogleins.
Authors: Ishii K , Amagai M , Hall R P , Hashimoto T , Takayanagi A , Gamou S , Shimizu N , Nishikawa T 
Published: January 2023

Abstract
Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are autoimmune skin diseases caused by autoantibodies against desmoglein (Dsg) 3 and Dsg1, respectively. Routine immunofluorescence testing of skin and serum from patients cannot distinguish between these two severe diseases since both have IgG Abs directed against keratinocyte cell surfaces. In this study, recombinant Dsg3 and Dsg1, produced as secreted proteins by baculovirus expression, have been utilized to develop ELISAs for the specific characterization of their autoantibodies. Of 49 PV sera, 46 were positive in the Dsg3 ELISA and 44 of 46 PF sera were positive in the Dsg1 ELISA, compared with only 3 of 23 sera of bullous pemphigoid, and none of 53 normal control sera in both ELISAs. Both the Dsg3 and Dsg1 ELISAs were more specific and sensitive than conventional immunofluorescence staining. These Ag-specific ELISAs revealed that more than one-half of PV sera (26 of 49) had anti-Dsg1 Abs in addition to anti-Dsg3 Abs. PV patients who had not only oral mucous lesions but also significant skin involvement tended to have higher titers of anti-Dsg1 Abs. Furthermore, the ELISA reactivity correlated well with clinical disease activity in 5 of 6 PV and 5 of 5 PF patients. This ELISA provides a sensitive and highly specific assay for the diagnosis of patients with PV and PF, the correlation of disease activity with serum Ab levels, and a novel tool for investigating the immunopathogenesis of pemphigus.
HIV-1 envelope-specific CD4+ T helper cells from simian/human immunodeficiency virus-infected rhesus monkeys recognize epitopes restricted by MHC class II DRB1*0406 and DRB*W201 molecules.
Authors: Lekutis C , Letvin N L 
Published: January 2023

Abstract
The HIV-1 envelope (Env)-specific Th cell response of rhesus monkeys infected with nonpathogenic chimeric simian/human immunodeficiency viruses (SHIV) was assessed at a molecular level by establishing rgp120-specific CD4+ T cell lines. Epitopes recognized by these MHC class II-restricted Th cells were identified within the second (C2), third (C3), and fifth (C5) conserved regions of HIV-1 gp120. The epitope located in C2 was found to be restricted by the rhesus monkey (Macaca mulatta) leukocyte Ag Mamu-DRB1*0406, and the Th cell epitope in C5 was found to be restricted by Mamu-DRB*W201. The restriction element requirements of the C2 and C5 epitope-specific CD4+ Th cells appear to be rather stringent, because these peptide epitopes were not recognized in the presence of other Mamu-DR expressing cell lines. The ability to analyze HIV-1 Env-specific CD4+ T cell responses in SHIV-infected monkeys will enhance the utility of this model for studying AIDS pathogenesis and for assessing novel HIV-1 vaccine strategies.
Affinity Maturation in Lyn Kinase-Deficient Mice with Defective Germinal Center Formation
Authors: Kato Jun , Motoyama Noboru , Taniuchi Ichiro , Takeshita Hiromichi , Toyoda Masaki , Masuda Keiji , Watanabe Takeshi 
Published: January 2023

AbstractLyn kinase-deficient (lyn−/−) mice show several abnormalities such as reduced numbers of circulating B cells, hyper-IgM, and low proliferative responses induced by CD40 ligand. Lyn−/− mice also develop splenomegaly, produce autoreactive Abs with age, and finally develop glomerulonephritis. Another abnormality observed in lyn−/− mice is that their disability to form germinal centers (GCs). It has been considered that GCs play an important role in affinity maturation and differentiation to B cell memory upon immunization with thymus-dependent Ag. Since Lyn kinase has been thought to be downstream of the signals from the B cell Ag receptor as well as CD40, we studied whether or not lyn−/− mice could exhibit normal Ag-specific class switching and affinity maturation following somatic hypermutation. The mice were immunized with (4-hydroxy-3-nitrophenyl)acetyl-chicken γ-globulin (NP-CG). Production of NP-specific IgG1 Abs was slightly reduced but clearly detectable. The affinity of Abs produced was comparable to that in wild-type mice. Furthermore, somatic hypermutation occurred in the heavy-chain variable region at the same level as that in wild-type mice. Therefore, we conclude that isotype switching and affinity maturation occur normally in lyn−/− mice without the formation of GCs. The results lead to a speculation that Lyn may not play a role in induction of isotype switching or affinity maturation, despite being downstream of the signals from the B cell Ag receptor complex and CD40, and that GC architecture may not be absolutely essential for affinity maturation.
Induction of Tolerance in B-1 Cells for Bromelain-Treated Mouse Red Blood Cells by a Transient Presence of Anti-Idiotype Antibodies in Neonatal and Adult Mice
Authors: Kawaguchi Susumu 
Published: January 2023

Abstract
Murine B-1 cells are thought to develop from Ig− progenitors early in ontogeny and to expand by self-renewal. To examine the early development of Ig+ precursors of B-1 cells for bromelain-treated mouse RBC, the transient presence of RidA, a rat anti-Id mAb for VH11/Vκ9-type anti-bromelain-treated mouse Abs, was produced in neonatal mice. The presence of RidA during days 0 to 10 of age resulted in an 80% reduction in peritoneal RidA-Id+ B cells and B cells secreting RidA-Id+ Ig after LPS stimulation in 8-wk-old mice. This suggests that most Ig+ precursors for adult RidA-Id+ B cells already exist in 10-d-old mice. However, RidA injected into mice on day 10 had to persist for &gt;4 days to result in a significant reduction in adult B cells. Similarly, although RidA injected into adult mice bound immediately to membrane Ig (mIg) of the peritoneal RidA-Id+ B cells, a RidA persistence for &gt;4 days was required to suppress LPS reactivity of peritoneal and splenic B cells. The binding of RidA to mIg preexisting on B cells has no apparent effect on the ability of neonatal B cells to expand clonally or on the ability of adult B cells to secrete RidA-Id+ Ig after LPS stimulation. Both abilities evidently are suppressed by the accumulation of reaction between freshly expressed mIg and RidA.