bluuebunny/crossref_metadata_2025_split huggingface dataset:
Erythrocyte complement receptor type 1 and interactions between immune complexes, neutrophils, and endothelium.
Authors: Beynon H L , Davies K A , Haskard D O , Walport M J 
Published: December 2022

Abstract
The deposition of immune complexes (IC) may play an important part in the pathogenesis of vasculitis. An increase in permeability of the vascular endothelial lining is a prerequisite for IC deposition. We used an in vitro model to examine the effects of interactions between IC, neutrophils, and endothelium on the integrity of endothelial cell monolayers. Human umbilical vein endothelial cells were grown to confluence on an FITC-labeled matrix, and monolayer integrity was assessed by the exclusion of an 125I-anti-FITC Ab. Alteration in endothelial monolayer permeability was associated with increased uptake of 125I-anti-FITC Ab, expressed as a percentage of the maximal uptake of Ab onto the FITC-matrix from which endothelial cells had been stripped. Neither resting nor cytokine-stimulated endothelial cells bound hepatitis B surface Ag (HBsAg/anti-HBsAg) IC. Immune complexes were shown to activate neutrophils to induce a 9.5% increase in the permeability of IL-1 beta-stimulated endothelium. This increase in endothelial permeability was abrogated by the addition of RBC bearing normal complement receptor type 1 (CR1) numbers (3.2%). This protective effect was shown to be related to the binding of IC to erythrocyte CR1 and was reduced by CR1 blockade using polyclonal rabbit anti-CR1 Abs. These observations demonstrate that IC are capable of directly activating neutrophils to induce increases in endothelial permeability, which may facilitate the deposition of circulating IC. The results support the hypothesis that the binding of IC to erythrocyte CR1 may inhibit damaging interactions between IC, neutrophils, and endothelium.
Quantitation of ICAM-1 expression in mouse lung during pneumonia.
Authors: Burns A R , Takei F , Doerschuk C M 
Published: December 2022

Abstract
In the systemic circulation, neutrophil emigration into sites of acute inflammation is mediated through the leukocyte adhesion complex, CD11/CD18. ICAM-1 is an inducible endothelial ligand for CD11a/CD18 and CD11b/CD18. Streptococcus pneumoniae elicits neutrophil emigration through a CD18-independent mechanism whereas Escherichia coli endotoxin elicits emigration through a CD18-dependent mechanism in rabbit lungs. To determine whether ICAM-1 is up-modulated in the lung during CD18-independent and CD18-dependent emigration, ultrastructural immunogold-labeling studies were performed on BALB/c mice given airway instillates of S. pneumoniae or E. coli endotoxin. Ultrathin cryosections of frozen lung tissue were immunogold labeled with the mAb YN1/1.7.4 against the murine homologue of human ICAM-1. Gold particles on the plasma membranes of alveolar endothelial and epithelial cells were quantitated by transmission electron microscopy. Capillary endothelial ICAM-1 expression did not change during neutrophil emigration toward S. pneumoniae, a CD18-independent pathway in rabbits. In contrast, ICAM-1 expression increased 4.2-fold in response to E. coli endotoxin (known to elicit CD18-dependent emigration in mice), suggesting that the mechanism of adhesion may be regulated by the expression of endothelial rather than neutrophil adhesion molecules. Constitutive expression of ICAM-1 on alveolar epithelial cells was 22-fold greater than on capillary endothelium. Epithelial expression was mainly restricted to type I pneumocytes, whereas type II pneumocytes, the precursors of type I cells, expressed little or no ICAM-1. However, during pneumonia, type II but not type I pneumocytes showed increased ICAM-1 expression, suggesting that ICAM-1 expression represents an early differentiation even in response to epithelial injury.
Association of IgA-Fc receptors (Fc alpha R) with Fc epsilon RI gamma 2 subunits in U937 cells. Aggregation induces the tyrosine phosphorylation of gamma 2.
Authors: Pfefferkorn L C , Yeaman G R 
Published: December 2022

Abstract
We investigated the possibility that IgA-binding chains of Fc alpha R on monocytic cells are physically associated with gamma 2 subunits of Fc epsilon RI (Fc epsilon RI gamma 2 or gamma 2). Fc alpha R was precipitated from lysates of IFN gamma-treated U937 cells, subclone 10.6, and probed by immunoblotting with Ab against human gamma 2. Fc alpha R was precipitated through anti-Fc alpha R mAbs A59 or A62, through A62 from lysates that had been exhaustively precleared of high affinity IgG-Fc receptors (Fc gamma RI) and of low affinity Fc gamma RII, and through anti-Fc alpha R mAb A77 from Fc gamma RI-precleared lysates of untreated 10.6 cells. precipitation was also performed through F(ab')2 A77 and through the native ligand of the receptor, hlgA. In all cases, Fc alpha R precipitates contained co-isolated 22-kDa gamma 2 (unreduced). The Fc alpha R alpha-chain/gamma 2 complex did not readily dissociate in 1% Nonidet P-40 as did Fc gamma RI alpha-chain/gamma 2, suggesting a novel aspect to the Fc alpha R subunit interaction. Specific Fc alpha R aggregation on cells triggered a robust respiratory burst and the tyrosine phosphorylation of several proteins. Among them was phospho-gamma 2, which migrated as a 24- to 28-kDa gamma 2 phosphoprotein on gels and was detected as a 28-kDa phosphoprotein by anti-phosphotyrosine immunoblot. Aggregated Fc alpha Rs that were precipitated from Fc alpha R-triggered cells also contained a phosphoprotein of the same mobility and immunoreactivity, as did aggregated Fc gamma RI from which the 28-kDa phosphoprotein could be more readily eluted and identified (as phospho-gamma 2). We concluded that myelocytic Fc alpha Rs are multichain complexes containing gamma 2 subunits that are tyrosine phosphorylated upon Fc alpha R aggregation. As IgA is the predominant Ig on mucosal surfaces, gamma-subunits may play an important role in mucosal immunity involving leukocytic Fc alpha R.
Monocyte vesiculation is a possible mechanism for dissemination of membrane-associated procoagulant activities and adhesion molecules after stimulation by lipopolysaccharide.
Authors: Satta N , Toti F , Feugeas O , Bohbot A , Dachary-Prigent J , Eschwège V , Hedman H , Freyssinet J M 
Published: December 2022

Abstract
Endotoxin-stimulated monocytes can elicit a dual procoagulant response. They express tissue factor and expose phosphatidylserine in the outer leaflet of the plasma membrane. Tissue factor, a membrane glycoprotein, is the cellular trigger of blood coagulation reactions. Phosphatidylserine is an essential anionic phospholipid for surface amplification of thrombin generation. In this study the distribution of these two procoagulant entities between activated monocytes and derived microparticles was assessed after stimulation by LPS. The presence of CD14, CD11a, and CD18, and possible associated adhesion potential were examined, particularly on microparticles. Tissue factor was evidenced by using a specific functional assay and flow cytometry. Phosphatidylserine exposure was monitored through its catalytic activity in a thrombin generation assay and by flow cytometry with the use of FITC-conjugated annexin V, a protein probe of anionic phospholipids. CD14, CD11a, and CD18 were detected by flow cytometry. The interaction of microparticle CD11a/CD18 with intracellular adhesion molecule-1 was demonstrated by using immobilized recombinant intracellular adhesion molecule-1 fusion protein. The major part of tissue factor and phosphatidylserine-dependent procoagulant activity was associated with microparticles after LPS stimulation. This was confirmed by flow cytometry. The presence of functional CD11a/CD18, and CD14 on microparticles testifies to an associated adhesion potential. These results show that membrane vesiculation could be responsible for dissemination of inducible monocyte procoagulant activities and suggest that derived microparticles could also participate in endothelium stimulation. This emphasizes the role of monocyte as a central element in the coupling between inflammation/infection and thrombosis.
T cell-independent and T cell-dependent B cell activation increases IFN-gamma R expression and renders B cells sensitive to IFN-gamma-mediated inhibition.
Authors: Abed N S , Chace J H , Cowdery J S 
Published: December 2022

Abstract
We have studied the relationship between B cell activation and the ability of IFN-gamma to inhibit B cell differentiation. The LPS activation of conventional and CD5+ B cells resulted in increased IFN-gamma R expression and increased the ability of IFN-gamma to inhibit LPS-induced B cell differentiation correlated with increased IFN-gamma R expression. We detected increased B cell IFN-gamma R expression 12 h after activation, and maximal IFN-gamma R expression was observed at 24 h. Activation of B cells by F(ab2)' anti-IgM induced a similar increase in IFN-gamma R expression. In autoimmune New Zealand Black mice, both conventional and CD5+ B cells showed a pattern of IFN-gamma R expression similar to that seen in DBA/2 mice, and both populations of B cells were sensitive to inhibition by IFN-gamma. To examine the role of IFN-gamma in the regulation of T cell-dependent B cell responses, we activated B cells with the CDC35 T cell line (which is specific for rabbit IgG). When rabbit anti-mouse Ig-treated B cells were activated by CDC35 T cells, we found that B cells exhibited increased IFN-gamma R expression by 48 h; we also found that IFN-gamma inhibited CDC35-mediated IgM secretion to a degree similar to IFN-gamma inhibition of T cell-independent B cell differentiation. Additionally, IFN-gamma inhibited CDC35-stimulated B cells even in the presence of exogenous IL-4 and IL-5. This study establishes the importance of IFN-gamma as a regulator of both T cell-independent and T cell-dependent B cell differentiation.
Analysis of IL-2 gene regulation in c-fos transgenic mice. Evidence for an enhancement of IL-2 expression in splenic T cells stimulated via TCR/CD3 complex.
Authors: Ochi Y , Koizumi T , Kobayashi S , Phuchareon J , Hatano M , Takada M , Tomita Y , Tokuhisa T 
Published: December 2022

Abstract
Effects of the deregulated c-fos gene product on IL-2 expression were studied in splenic T cells from c-fos transgenic (H2-c-fos) mice. IL-2 gene expression and IL-2 production by H2-c-fos T cells stimulated with immobilized anti-CD3 Abs were enhanced and prolonged as compared with those by control T cells. Activator protein-1 activity in nuclear extract from the H2-c-fos T cells was also higher than that from the control cells. There was no significant difference in the activity of other transcription factors including IL-2 kappa B, NFAT, and Oct-1, between the H2-c-fos and the control T cells. However, activity of a negative regulatory element binding factor (NRE-A) in the H2-c-fos T cells was much lower than that in the control cells. These results suggest that c-Fos/activator protein-1 is a major regulatory factor for IL-2 gene expression in splenic T cells activated through the TCR/CD3 complex.
Demonstration of organic anion transport in T lymphocytes. L-lactate and fluo-3 are target molecules.
Authors: Sommer F , Bischof S , Röllinghoff M , Lohoff M 
Published: December 2022

Abstract
In this paper, we describe for the first time the existence of organic anion transport in T lymphocytes, exemplified by the transmembrane transport of the anions L-lactate and the Ca2+ indicator fluo-3. The transport of either anion was found to be inhibitable by probenecid, a common blocker of organic anion transport. Transport of L-lactate was observed in long-term cultured T cell lines, as well as in freshly ex vivo isolated T cells, and occurred via a saturable, pH-dependent, and stereospecific process. L-Lactate uptake was dependent on the activation state of the T cells, because activation of T cells by Con A strongly enhanced accumulation of L-lactate from the medium. Because L-lactate may be transported bidirectionally through the T cell membrane in vivo, different physiologic roles of L-lactate transport are discussed. L-Lactate uptake may serve as an alternative source of energy in an inflamed, glucose-deficient tissue or may represent a prerequisite for the earlier-published immunoregulatory function of this molecule on T cells. On the other hand, release of L-lactate emerging from glycolysis could be necessary to avoid acidification of the cell. The fact that the Ca2+ indicator fluo-3 is also transported through the cellular membranes of long-term cultured T cells via organic anion transport has important implications for the determination of Ca2+ influx into T cells. Even though the transport of both molecules, L-lactate and fluo-3, represents organic anion transport, evidence is presented that confirms that the respective transport systems are different.
Lack of allelic exclusion permits autoreactive B cells to escape deletion.
Authors: Iliev A , Spatz L , Ray S , Diamond B 
Published: December 2022

Abstract
The R4A-gamma 2b transgenic mouse harbors the gene for the gamma 2b heavy chain of an anti-dsDNA Ab. Approximately 80% of B cells expressing the transgene display allelic exclusion. Although the transgenic mice have little to no detectable serum anti-DNA activity, splenic B cells can be stimulated in vitro with LPS to secrete anti-DNA Ab. Hybridomas derived from LPS-stimulated splenic B cells were analyzed for expression of the transgene and for DNA binding. All nine transgene-encoded anti-DNA-producing lines were found to express an endogenous IgM heavy chain. Of 19 randomly selected lines producing a transgene-encoded non-DNA binding Ab, none expressed a second heavy chain. The tight correlation between lack of allelic exclusion and anti-dsDNA specificity provides strong support for the hypothesis that a major function of allelic exclusion is to prevent the maintenance of a pool of potentially activatable autoreactive cells.
Identification of the IgA-binding region in streptococcal protein Arp.
Authors: Johnsson E , Andersson G , Lindahl G , Hedén L O 
Published: December 2022

Abstract
Cell surface proteins that bind to the Fc part of human IgA are expressed by different species of pathogenic streptococci. The most extensively characterized streptococcal IgA-binding protein is the Streptococcus pyogenes protein Arp4, a member of the M protein family. Here we describe work that identifies the IgA-binding region in this streptococcal protein. A comparison of the amino acid sequences of protein Arp4 and four other IgA-binding proteins of S. pyogenes first made possible the identification of a putative IgA-binding region. Site-specific mutagenesis and generation of deletions were then used to show that Arp4 derivatives lacking different parts of the putative IgA-binding region had lost the ability to bind IgA. Conclusive evidence for the localization of the IgA-binding region was obtained through the characterization of a chimeric protein, in which the putative IgA-binding region of Arp4 had been introduced into another S. pyogenes cell surface protein that does not bind IgA. Our data show that a region comprising 29-amino acid residues in the N-terminal part of Arp4 is necessary and sufficient for IgA-binding capacity. Competitive inhibition experiments with synthetic peptides indicated that the C-terminal half of this 29 residue region may be most important for the IgA-binding property of Arp4. These results identify, for the first time, the ligand-binding region in an Fc alpha binding protein.
Five putative subclasses of swine IgG identified from the cDNA sequences of a single animal.
Authors: Kacskovics I , Sun J , Butler J E 
Published: December 2022

Abstract
We report the sequences of more than 40 partial and complete swine C gamma cDNAs obtained by PCR cloning of first strand cDNA, and from a cDNA expression library, all from a single animal. These seem to represent five IgG subclasses, that can be grouped into two clusters; one contains IgG1 and IgG3 and the other, IgG2a, IgG2b and IgG4. IgG2a and IgG2b differ by only three amino acids, but single strand conformational polymorphism analyses of PCR-amplified IgG2-specific segments in animals of different breeds, argues for their putative subclass status. Major subclass differences are found in the hinge and C gamma 3, but differences in upper hinge length, associated with segmental flexibility in the IgGs of other species, are absent. All subclasses have identical middle hinge segments that can accommodate three interheavy chain disulfide bridges. The putative swine IgG subclasses have their greatest similarity with those of the human except for the near absence of hinge region variation. Swine subclasses such as ruminant IgG2a, have a lower hinge deletion which in human IgG1, contains one of the motifs believed necessary for interaction with Fc gamma Rs. IgG1 was the most frequently encountered subclass cDNA (25 of 43) and the single swine-mouse hybridoma tested had a sequence identical to IgG1. Partial sequence analyses of genomic clones identified one clone identical with the IgG1/IgG3 subclass cluster, two identical to the IgG2b/IgG4 subclass group, and two identical to each other but different from any of the expressed sequences reported here. Genomic blots suggest that up to eight C gamma genes are present in the genome.
Synergistic cooperation between phorbol ester and IFN-gamma for induction of nitric oxide synthesis in murine peritoneal macrophages.
Authors: Jun C D , Choi B M , Hoon-Ryu  , Um J Y , Kwak H J , Lee B S , Paik S G , Kim H M , Chung H T 
Published: December 2022

Abstract
The role of protein kinase C (PKC) in the induction of nitric oxide (NO) synthesis in murine peritoneal macrophages was examined. Phorbol ester, a PKC activator, had no effect on NO synthesis by itself, whereas IFN-gamma alone had modest activity. When phorbol ester was used in combination with IFN-gamma, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. This increase in NO synthesis was reflected as increased amount of inducible NO synthase (iNOS) mRNA, as determined by Northern blotting. The optimal effect of phorbol ester was shown at 6 h after treatment with IFN-gamma. Phorbol ester also induced the release of NO to the incubation medium by bacillus Calmette-Guerin-infected peritoneal macrophages. Prolonged incubation of cells with phorbol ester, which down-regulates PKC activity, abolished the synergistic cooperative effect on NO production with IFN-gamma. In addition, such PKC inhibitors as staurosporin or polymyxin B reduced NO production induced by IFN-gamma plus phorbol ester. When the cells were treated with both actinomycin D and phorbol ester after IFN-gamma stimulation, more NO was produced and more iNOS mRNA was expressed than in the cells treated with actinomycin D alone. On the basis of these observations, we conclude that PKC might not be directly involved in the expression of NO synthase, but, instead, might be involved in the stabilization of the iNOS mRNA already expressed by the treatment of IFN-gamma.
Contribution of tyrosine kinases to the selective orientation of human CD4+ bifunctional cloned T cells toward proliferation or cytolytic function.
Authors: Eljaafari A , Soula M , Dorval I , Pirenne H , Quelvennec E , Bernard A , Fagard R , Sterkers G 
Published: December 2022

Abstract
We show that T cell activation of human CD4+ cloned T cells through the CD2 molecule can induce either autocrine proliferation or cytolysis, depending on the pair of anti-CD2 mAbs used for stimulation, that is, D66/T11(1) or GT2/T11(1), respectively. As the earliest biochemical event after CD2 stimulation is likely the induction of tyrosine phosphorylation of various proteins, we investigated whether differential activation of protein tyrosine kinases (PTKs) could contribute to the selective induction of each function. Results show that herbimycin A, a potent PTK inhibitor, markedly decreased the induction of both proliferation and cytolysis. This implies a regulatory role for tyrosine phosphorylation in the induction of each function by CD2. However, that PTKs are differentially activated upon induction of proliferation by D66/T11(1) or cytotoxic function by GT2/T11(1) emanated from two different approaches. First, immunoblotting total cellular extracts with an anti-phosphotyrosine mAb showed different patterns of tyrosine phosphorylation depending on the pair of CD2 mAbs used for stimulation. Second, a differential activation of p56lck, a src-related PTK, was observed after stimulation with D66/T11, and GT2/T11(1). Although induction of proliferation by D66/T11(1) was correlated with increased Lck activity, this was not observed when cells were triggered to lyse by GT2/T11(1). Thus, by providing striking correlative evidences linking differences in PTK activation with induction of different functions in bifunctional cloned T cells, our results strongly suggest that PTKs may contribute to the selective orientation of T cell functions at a single-cell level.
Immunological tolerance to a defined myelin basic protein antigen administered intrathymically.
Authors: Goss J A , Nakafusa Y , Roland C R , Hickey W F , Flye M W 
Published: December 2022

Abstract
To explore the mechanisms responsible for the development of tolerance to allografts after intrathymic (IT) injection of alloantigen, the well-defined model of experimental autoimmune encephalomyelitis (EAE), which mimics the human autoimmune disease multiple sclerosis, was used. This inflammatory neurologic syndrome is initiated by myelin basic protein (MBP)-reactive CD4+ T lymphocytes restricted to self-MHC class II molecules. Naive adult, EAE-susceptible Lewis (RT1(1) rats were treated IT, i.v., or i.p. with a single dose (100 micrograms) of guinea pig-myelin basic protein (GP-MBP 1-176) in PBS plus 1 ml rabbit anti-rat lymphocyte serum i.p. Twenty-one days later, all rats were challenged by intradermal hind footpad injections of 50 micrograms GP-MBP in PBS emulsified in CFA. Only IT, but not i.p. or i.v., administration of GP-MBP plus anti-lymphocyte serum conferred marked resistance to a subsequent systemic challenge of GP-MBP, as demonstrated by the prevention of weight loss and paralysis characteristic of EAE. The IT administration dramatically decreased the size and number of histologic perivascular infiltrates observed per visual field in spinal cord of the tolerant animals and decreased GP-MBP-specific T lymphocyte in vitro proliferation (p &lt; 0.01), whereas proliferation to a nonspecific mitogen (Con A) was not altered. With the addition of rIL-2, the decreased Ag-specific proliferative responses of IT-treated animals increased to control levels. Adoptive transfer of 100 x 10(6) splenocytes from tolerant hosts i.v. to naive syngeneic Lewis rats challenge with 100 micrograms GP-MBP in CFA had no effect on clinical or histologic EAE. Exposure of MBP to maturing thymocytes results in functionally immunounresponsive lymphocytes and prevention of autoimmune EAE.