bluuebunny/crossref_metadata_2025_split huggingface dataset:
A mutation of the mu transmembrane that disrupts endoplasmic reticulum retention. Effects on association with accessory proteins and signal transduction.
Authors: Stevens T L , Blum J H , Foy S P , Matsuuchi L , DeFranco A L 
Published: December 2022

Abstract
The mu heavy chain has an unusually high content of hydroxyl-containing amino acids in its membrane-spanning region. We have examined the involvement of two of these hydrophilic residues in endoplasmic reticulum (ER) retention, interactions with Ig-alpha/Ig-beta, and transmembrane signaling. Neighboring tyrosine and serine residues were mutated to either phenylalanine and alanine (mutant YS/FA) or valine and valine (mutant YS/VV). Membrane Ig (mIgM) molecules containing these mutant mu chains were expressed on the surface of transfected B lymphoma cells. Anti-Ig-induced signaling by the YS/FA mutant mIgM was equivalent to wild-type (wt) mIgM, whereas signaling by the YS/VV mutant mIgM was notably diminished. Association between mutant YS/VV mIgM and Ig-alpha/Ig-beta was detectable but reduced in comparison to YS/FA or wt mIgM. Signaling by YS/VV mutant mIgM appeared to involve Ig-alpha/Ig-beta, because these proteins were tyrosine phosphorylated on receptor cross-linking. When YS/VV and wt mu chains were cotransfected with light chains into nonlymphoid cells, mutant mIgM was expressed at the cell surface in the absence of Ig-alpha/Ig-beta, whereas wt mIgM was not. These data suggest that the mutated residues contribute to ER retention and directly or indirectly to association with Ig-alpha/Ig-beta. Moreover, ER retention can be disrupted without preventing functional association with Ig-alpha/Ig-beta. In addition, these data indicate that the hydroxyl groups of the mutated residues are not required for functional association between mu and Ig-alpha/Ig-beta because their removal did not reduce the ability of the YS/FA mutant mIgM to associate with accessory proteins or to participate in signal transduction.
The origin of the primate Mhc-DRB genes and allelic lineages as deduced from the study of prosimians.
Authors: Figueroa F , O'hUigin C , Tichy H , Klein J 
Published: December 2022

Abstract
MHC class II genes of the DRB family were partially sequenced from 10 individuals representing six species of prosimians: Galago senegalensis, G. moholi, Otolemur garnetti, Loris tardigradus, Petterus (Lemur) fulvus, and Lemur catta. Altogether, 41 different genes were discerned, all distinct from genes identified previously. Comparative analysis of the sequences has led to the following conclusions. First, the DRB loci present in human populations diverged from one another before the divergence of prosimian and anthropoid primates. Second, major allelic lineages of the DRB1 locus, such as DRB1*03 (DRB1*13) and DRB1*04, were established more than 85 million years ago. Third, the DRB6 gene was inactivated before the separation of prosimians and anthropoids, and has remained a pseudogene for more than 85 million years. Fourth, the primate DRB region is structurally and functionally unstable. In Lemur catta, for example, all DRB genes have apparently been lost and their function taken over by DOB and/or DPB genes. DRB genes are, however, present in a related species, Petterus (Lemur) fulvus. Fifth, the prosimian DRB3 genes are all inactive; their function seems to have been taken over by new genes. Sixth, several of the prosimian DRB genes and pseudogenes have recently been duplicated. In Otolemur garnetti, for example, one chromosome carries at least three copies of the DRB3 pseudogene.
Effects of human class I transgenes on Toxoplasma gondii cyst formation.
Authors: Brown C R , David C S , Khare S J , McLeod R 
Published: December 2022

Abstract
MHC class I genes are important in the regulation of cyst number in mice perorally infected with Toxoplasma gondii. Since human MHC class I molecules may be capable of functioning as restriction elements in mice, to determine whether class I genes also control outcome of T. gondii infection for humans, a transgenic mouse model was developed using human class I genes in mice. Human HLA-B27 and Cw3 transgenic mice, with the cyst-susceptible B10 mouse background, were tested for resistance to cyst formation after peroral infection with the Me49 strain of T. gondii. Introduction of the B27 gene into susceptible mice made them even more susceptible to T. gondii brain cyst formation. In contrast, HLA-DB27 transgenic mice that have a substitution of the alpha 3 portion of the human class I molecule with the alpha 3 portion of the mouse Kd molecule had the same number of brain cysts as susceptible B10 control mice when perorally infected. Similarly, HLA-Cw3 transgenic mice had the same number of brain cysts as the susceptible B10 controls. These results indicate that the interaction between CD8 on mouse T cells and the human class I molecule in transgenic mice does not always occur, and sometimes may hinder a normal response. Furthermore, B27 and Cw3 transgenes did not generate resistance to cyst formation in infection by T. gondii.
Isolation of neutralizing anti-C5a monoclonal antibodies from a filamentous phage monovalent Fab display library.
Authors: Ames R S , Tornetta M A , Jones C S , Tsui P 
Published: December 2022

Abstract
A panel of mAbs against the activated complement component C5a was obtained from a filamentous phage M13-Fab display library generated from mice immunized with human rC5a. Fabs isolated from the library after iterative selection vs rC5a bound to both rC5a and purified C5. To isolate Fabs specific for neoepitopes expressed on C5a but not on the native complement component C5 the library was rescreened in a competitive manner. The phage Fab library was first incubated with immobilized C5 to deplete C5 reactive Fabs. The C5 nonadherent phage were then incubated with immobilized rC5a in the presence of soluble C5. Bound phage were eluted and subjected to two additional cycles of subtraction with immobilized C5 and selection with immobilized rC5a in the presence of soluble C5. After three cycles of this competitive biopanning four Fabs reactive with rC5a were isolated. Two bound preferentially with and neutralized C5a. Competitive biopanning of phage display libraries may increase the probability of identification of Abs of the desired specificity.
Proteinase 3. A neutrophil proteinase with activity on platelets.
Authors: Renesto P , Halbwachs-Mecarelli L , Nusbaum P , Lesavre P , Chignard M 
Published: December 2022

Abstract
Purified proteinase 3 (PR3) devoid of any elastase (HLE) and cathepsin G (Cat.G) contaminants, was prepared from azurophilic granules of human polymorphonuclear neutrophils by using a novel procedure. Although unable to induce platelet activation (up to 25 micrograms/ml) by itself, PR3 at a concentration as low as 2.5 micrograms/ml enhanced the platelet response to a concomitantly added threshold concentration of Cat.G, a recognized platelet agonist. In the presence of 10 micrograms/ml PR3, aggregation and degranulation of platelets induced by Cat.G were 43.2 +/- 5.9% and 27.1 +/- 1.9% as compared with 5.5 +/- 2.9% and 4.2 +/- 1.5% (n = 4) for Cat.G alone. This enhancing effect by PR3 was also observed with collagen and a cyclic endoperoxide analogue, and was inhibited by eglin C and elafin, two PR3 inhibitors. Associated with the removal of activity by a anti-PR3 mAb and the lack of effect of the secretory leukocyte proteinase inhibitor, these data demonstrated that the effect is specifically related to the enzymatic activity of PR3. It is hypothesized that this mechanism could play a role in the polymorphonuclear neutrophil-mediated platelet activation, an event already known to be dependent on Cat.G and HLE. This is supported by the fact that the association of PR3 and HLE, at concentrations ineffective by themselves, was able to potentiate Cat.G-induced platelet activation.
Characterization of a new functional TCR J delta segment in humans. Evidence for a marked conservation of J delta sequences between humans, mice, and sheep.
Authors: Davodeau F , Peyrat M A , Hallet M M , Vié H , Bonneville M 
Published: December 2022

Abstract
Through analysis of TCR delta-chain cDNA derived from human gamma delta T cell clones and polyclonal gamma delta T cell lines, we isolated a novel functional J delta gene segment (termed J delta 4) whose genomic fragment has been mapped within the TCR-delta locus between J delta 2 and J delta 1. Frequency of J delta 4 use was estimated among adult gamma delta PBL by using V delta 1, V delta 2, and V delta 5 genes. In all cases, this new J element was used at a low, albeit significant frequency, close to that of J delta 2. Finally, like human J delta 1 and J delta 2, which show a high degree of homology with their counterparts in the mouse and sheep, but unlike other J gamma, J beta, or J alpha elements, J delta 4 turned out to be highly homologous to a recently described ovine J delta. These results suggest the existence of strong selective pressures, possibly linked to an Ag-driven process, leading to specific conservation of J delta sequences among these three species.
Synergistic transcriptional activation of the IL-8 gene by NF-kappa B p65 (RelA) and NF-IL-6.
Authors: Kunsch C , Lang R K , Rosen C A , Shannon M F 
Published: December 2022

Abstract
Transcriptional activation of the IL-8 gene by several inflammatory mediators, including the cytokines IL-1 and TNF-alpha, is mediated through sequences located between nucleotide -94 and -71 of the IL-8 promoter. Because adjacent binding sites for the inducible transcription factors NF-kappa B and NF-IL-6 are located within this region, we examined the functional interaction of these two transcription factor families in IL-8 gene regulation. Maximal transcriptional activation by PMA in Jurkat T lymphocytes was shown to require intact binding sites for both NF-kappa B and NF-IL-6. Electrophoretic mobility shift analysis indicates that NF-IL-6, as well as other related members of this family, bind specifically to the NF-IL-6 site in the IL-8 promoter. In addition, NF-kappa B p65 (RelA), but not NF-kappa B p50 (NFKB1), binds specifically to the NF-kappa B site. When incubated together, RelA and NF-IL-6/C/EBP form a ternary complex with this region of the IL-8 promoter; this binding is dependent on intact binding sites for both NF-IL-6 and RelA. Transient cotransfection analyses indicate that the cooperative association of NF-IL-6 and RelA with the IL-8 promoter results in synergistic transcriptional activation. Mutational analyses of RelA demonstrate that the C-terminal transactivation domain and the DNA binding domain are required for synergistic activation with NF-IL-6. In addition, overexpression of the NF-kappa B inhibitor molecule, I kappa B, abolished the RelA- and RelA/NF-IL-6-dependent synergistic activation. These data demonstrate that RelA and members of the C/EBP/NF-IL-6 family can functionally cooperate in transcriptional activation of the IL-8 gene and suggest a common mechanism for inducible regulation of cytokine gene expression.
Transcriptional regulation of the TCA3 gene in mast cells after Fc epsilon RI cross-linking.
Authors: Oh C K , Metcalfe D D 
Published: December 2022

Abstract
TCA3 is a pro-inflammatory cytokine expressed in mast cells after activation. To examine how this gene is regulated, TCA3 mRNA levels were examined and nuclear run-on experiments and promoter analysis were performed. Northern blot analysis showed that TCA3 message appeared in mast cells within 2 h after induction, with a t1/2 of 30 min. Nuclear run-on experiments revealed that the appearance of TCA3 mRNA occurred in large part because of an increase in the level of de novo transcription. Analysis of the promoter region demonstrated that inducible gene expression was directed by a region extending between 1.324 kb and 0.082 kb upstream from the transcription start site. There was a 60- to 80-fold induction with TCA3 CAT constructs extending between 1.324 kb and 0.324 kb upstream from the transcription start site after treatment with PMA/A23187 and a 30- to 40-fold induction with Fc epsilon RI cross-linking. There was a seven- to eightfold induction with the region extending between 0.136 kb and 0.082 kb upstream from the transcription start site. TCA3 CAT constructs containing regions encompassing either the 0.042 kb or 2.0 kb sequence from the transcription start site were not able to direct CAT-protein synthesis. The TCA3 5' flanking sequence contained negative regulatory activity. Electrophoretic mobility shift assays revealed that protein in nuclear extracts of activated mast cells bound to an NF-kappa B element of the TCA3 gene. These findings demonstrate that the TCA3 gene is regulated transcriptionally in mast cells, with minimal promoter sequences contained within the 0.082 kb upstream region of the TCA3 gene; a putative enhancer NF-kappa B element is contained between 0.324 kb and 0.136 kb and a putative inhibitory element is contained between 1.324 kb and 2.0 kb upstream from the transcription start site.
Functional platelet-activating factor receptors are expressed by monocytes and granulocytes but not by resting or activated T and B lymphocytes from normal individuals or patients with asthma.
Authors: Simon H U , Tsao P W , Siminovitch K A , Mills G B , Blaser K 
Published: December 2022

Abstract
Platelet-activating factor (PAF) may play a role in the regulation of immune responsiveness and is a potent mediator in asthmatic inflammation. However, as yet, the mechanisms whereby PAF mediates its pleiomorphic effects on immune cells have not been elucidated. Because PAF is a potent chemotactic factor for eosinophils, the presence of receptors for PAF (PAFR) on lymphocytes may provide a mechanism for the concurrent recruitment of both eosinophils and T lymphocytes into the airways of asthmatic patients. To address this issue, we have examined freshly isolated PBMC and granulocytic cells as well as various T and B lymphocyte lines with regards to PAFR expression and PAF-induced changes in intracellular calcium concentration. Using two-color immunofluorescence techniques and highly purified cell populations, it was not possible to detect surface PAFR protein or functional PAFR on resting and in vivo or in vitro activated T and B cells derived from nonallergic individuals or patients with allergic asthma. In addition, we were unable to detect PAFR mRNA, protein, or functional response to PAF in human or murine T cell lines. In contrast, we found functional PAFR in most B lymphoblastoid cell lines. Within the PBMC population, CD14+ cells respond to PAF. These results suggest that PAF does not interact directly with lymphocytes and thus that previous observations suggestive of such an interaction likely reflect the effects of PAF on monocytes. PAF-induced increases in intracellular calcium concentration were also detected in neutrophils and eosinophils, but were lower in granulocytes relative to the levels detected in monocytes.
Production, selection, and maturation of thymocytes with high surface density of TCR.
Authors: Lucas B , Vasseur F , Penit C 
Published: December 2022

Abstract
The main steps in intrathymic T cell differentiation have been defined using bromodeoxyuridine as a postmitotic cell tracer. Thymocytes with a high surface expression of the TCR are generated in the first 24 h after DNA synthesis. The phenotype of these TCR(high) cells was studied during 10 days by using pairs of surface markers associated with BrdUrd. During the first 2 days, TCR(high) cells were of the CD4+CD8+HSA(high) phenotype, transiently expressed the early activation marker CD69, and contained a high percentage of cycling cells. This activation step preceded the transition from CD4+CD8+ to CD4+CD8- and then to CD4-CD8+ cells, followed by progressive HSA down regulation and increase in the expression of H-2K, Qa-2, and CD45RB. The phenotypic maturation was completed in 9 days. In Mls-1a mice, negative selection of V beta 6+ cells was observed at the earliest step of TCR(high) cell generation, and positive selection of V beta 8.2+ and V beta 14+ cells took place later and was correlated to the activation step. These data suggest that high TCR expression and cell activation are necessary for positive selection and subsequent T cell maturation.
Evidence for protein tyrosine kinase involvement in ligand-induced TCR/CD3 internalization and surface redistribution.
Authors: Luton F , Buferne M , Davoust J , Schmitt-Verhulst A M , Boyer C 
Published: December 2022

Abstract
Triggering of the TCR/CD3 complex can lead to its internalization and modulation from the cell surface. In the present study, we address the question of the dependence of internalization on protein tyrosine kinase (PTK) activation. With use of an activating anti-clonotypic (anti-Ti) mAb on a CTL clone, we have shown that the PTK inhibitors genistein and tyrphostin 25 delayed anti-Ti-induced internalization, but did not affect fluid phase protein uptake or transferrin receptor cycling. Confocal microscopy with use of fluorescent anti-Ti mAb revealed that the inhibition of TCR internalization corresponded to the induction of large patches that were localized in cell membrane areas depleted of polymerized actin, the formation of which was dependent on the combined action of the anti-Ti mAb and the PTK inhibitors. In contrast to the effect of these PTK inhibitors, depletion of Src-like PTKs by T cell pretreatment with herbimycin A led to an increased rate of anti-Ti-induced internalization. Internalization induced by the monovalent Fab fraction of anti-Ti mAb was similarly affected by the PTK inhibitors, although the extent of induced internalization was less by approximately one-half. An analysis of substrates phosphorylated in kinase assays on TCR/CD3 immunoprecipitates of the CTL, which were activated by anti-Ti mAb in both the absence and presence of genistein, identified protein bands in which phosphorylation or association with CD3 was inhibited in the presence of genistein. Thus, a genistein-sensitive PTK activity seems to control ligand-induced TCR/CD3 complex redistribution and internalization.
TNF-alpha inhibits the further development of committed progenitors while stimulating multipotential progenitors in mouse long-term bone marrow cultures.
Authors: Rogers J A , Berman J W 
Published: December 2022

Abstract
We studied simultaneously the effect of TNF on both relatively primitive and more mature hematopoietic progenitors by using a modification of the mouse long-term bone marrow culture system of Dexter. Mycophenolic acid-treated long-term bone marrow cultures were charged with stromally depleted bone marrow cells along with 10 to 500 U/ml recombinant human TNF-alpha, and assayed each week for 5 wk for the presence of primitive (CFU-S and high proliferative potential colony-forming cell) and mature (CFU-C) colony-forming units. The results demonstrate that TNF-alpha has differential effects on hematopoiesis; it virtually eliminates CFU-C, significantly lowers high proliferative potential colony-forming cell (CFC) numbers and increases CFU-S numbers. This effect appears to be independent of CSF production in the cultures as shown by protein assays. Northern blot analyses showed no differences in expression of CSF genes or any expression of those encoding for IL-1, IL-3, or IL-6. These results, obtained in a long-term culture system that closely mimics in vivo bone marrow, demonstrate that many of the apparently contradictory effects of TNF observed in vitro occur concomitantly and are attributable to the presence of cells at various stages of maturity in the cultures. The data suggest a mechanism of this activity in which TNF is able to block the differentiation of primitive progenitors even as they are stimulated to proliferate.
Regulation of monocyte integrin expression by beta-family chemokines.
Authors: Vaddi K , Newton R C 
Published: December 2022

Abstract
In the present study we investigated the ability of three monocyte chemokines (MCP-1, MIP-1 alpha, and RANTES) to modulate monocyte adhesion molecules in an attempt to evaluate their potential to induce tissue infiltration of macrophages in vivo. All three chemokines tested induced increased expression of the alpha-chains of two members of beta 2 family of integrins, CD11b and CD11c, and their common beta-chain (CD18). They had no effect on CD11a expression. Enhancement of CD11b and CD11c was dose dependent and followed a distinct time course with peak levels at 4 h. Levels declined to reach basal levels by 24 h. In contrast, IL-1 induced enhancement remained high after 24 h of stimulation. However, the increases caused by chemokines were not mediated by IL-1 as indicated by lack of inhibition by the IL-1R antagonist. Studies on the mechanism of integrin up-regulation showed that mobilization of cytosolic free calcium is an important signaling event in this response and that up-regulation is associated with mobilization from intracellular pools mediated by microtubules. Enhanced CD11b and CD11c expression by chemokines was also found to result in enhancement of monocyte binding to endothelial cells. Further studies indicated that monocyte binding to endothelial cells follows similar dose-response kinetics as the up-regulation of integrins and can be partially blocked by Abs to CD11b and CD11c. These results suggest that modulation of the integrin expression by chemokines may facilitate the tissue trafficking of monocytes during inflammation.
Lung monocyte chemoattractant protein-1 gene expression in bleomycin-induced pulmonary fibrosis.
Authors: Zhang K , Gharaee-Kermani M , Jones M L , Warren J S , Phan S H 
Published: December 2022

Abstract
Recent studies indicate that monocyte chemoattractant protein-1 (MCP-1) may play an important role in pulmonary inflammation. In vitro studies show that a number of cell types are capable of producing MCP-1. In this study, MCP-1 expression in lungs of rats with bleomycin (BLM)-induced pulmonary fibrosis is examined to evaluate its cellular origin and potential role in pathogenesis. Lung fibrosis was induced in male Fisher 344 rats by endotracheal injection on day 0. On selected days after injection, lungs were harvested for in situ and Northern hybridization analyses for MCP-1 mRNA expression, immunochemical and histochemical analyses for MCP-1 protein expression, and identification of cell type. Northern analysis revealed significant elevation in lung MCP-1 mRNA expression beginning on day 3 post-BLM treatment, increasing to a peak on day 7, and then decreasing toward control levels after day 21. In situ hybridization combined with histochemical staining with chromotrope 2R indicate that most of the cells expressing MCP-1 mRNA at these time points are primarily eosinophils. A few scattered reactive fibroblasts, some mononuclear cells, epithelial cells, and cells of certain blood vessel walls also express this mRNA. Increased MCP-1 protein expression also was found to be predominantly within and adjacent to eosinophils. The eosinophils expressing this mRNA were found predominantly within areas of active fibrosis. The kinetics of increase in the number of cells expressing significant MCP-1 mRNA in lung sections paralleled that for MCP-1 mRNA expression, as assessed by Northern analysis. These results, for the first time, demonstrate that MCP-1 is up-regulated significantly in this rat animal model, and that infiltrating eosinophils represent the major cellular source for this increased MCP-1 expression.