bluuebunny/crossref_metadata_2025_split huggingface dataset:
Overexpression of CD3 eta during thymic development does not alter the negative selection process.
Authors: Hussey R E , Clayton L K , Diener A , McConkey D J , Howard F D , Rodewald H R , D'Adamio L , Dallenbach F , Stein H , Schmidt E V 
Published: December 2022

Abstract
To elucidate the role of CD3 eta in thymic development and to determine whether CD3 eta is involved in the negative selection process, CD3 eta was overexpressed &gt; 100 fold in transgenic (tg) mice using a Thy-1 promoter and regulatory elements. CD3 eta was readily observed in the majority of cortical thymocytes and in a fraction of medullary thymocytes in tg mice by immunohistochemical staining with an anti-CD3 eta-specific mAb. In contrast, endogenous CD3 eta levels were too low to detect in normal littermates. Flow cytometric analysis demonstrated an increased level of TCR on thymocytes with intermediate TCR density in tg animals and parallel biochemical studies showed a marked increased in TCR-associated CD3 zeta-eta heterodimers and CD3 eta-eta homodimers relative to controls. Despite this change in surface TCR phenotype, there was no significant alteration in the total numbers or proportion of CD4+CD8+ double-positive or CD4+CD8- or CD4-CD8+ single-positive thymocytes or peripheral T cells. Percentages of SP V beta 5, V beta 6, and V beta 8 thymocytes in tg animals were unaltered compared to normal littermates when backcrossed either to C57BL/6 (H-2b) or DBA/2 (H-2d) backgrounds. Furthermore, induction of DNA fragmentation with anti-CD3 epsilon mAb treatment in vivo was not significantly different for tg and normal littermates. Collectively, these data imply that CD3 eta is not a limiting component of the negative selection process.
Structurally distinct T cell receptor complexes on developmentally distinct T cell populations in severe combined immunodeficiency mice expressing a TCR beta transgene.
Authors: Shores E W , Nakayama T , Wiest D L , Takahama Y , Sharrow S , Singer A 
Published: December 2022

Abstract
T cell differentiation and TCR expression were assessed in severe combined immunodeficiency (SCID) mice possessing an already rearranged TCRV beta 8 transgene. Unlike nontransgenic SCID mice, TCRV beta 8-transgenic SCID mice contained a broad spectrum of T cell populations, including both immature thymocytes and mature T cells. In TCRV beta 8-transgenic SCID mice, immature CD4-CD8- and CD4+CD8+ thymocytes expressed surface TCR complexes structurally distinct from those expressed by mature single-positive T cells. Immature CD4+CD8+ thymocytes expressed surface TCR beta chains without a clonotypic TCR partner chain and largely without associated CD3 components. In contrast, mature single-positive T cells expressed fully assembled surface TCR complexes containing disulfide-linked heterodimers consisting of transgenic TCR beta chains and endogenous TCR alpha chains. The surface TCR complexes on mature T cells were associated with CD3 components and were competent to transduce TCR-mediated proliferative signals. Thus, T cells at different stages of development in TCRV beta 8-transgenic SCID mice express structurally distinct surface TCR complexes, demonstrating that the developmental stage achieved by T cells in these mice is related to the structure of the surface TCR complexes they express. Indeed, the present results indicate that successful differentiation into single-positive T cells requires surface expression of fully assembled TCR complexes.
The cell-mediated response to schistosomal antigens at the clonal level. III. Identification of soluble egg antigens recognized by cloned specific granulomagenic murine CD4+ Th1-type lymphocytes.
Authors: Chikunguwo S M , Quinn J J , Harn D A , Stadecker M J 
Published: December 2022

Abstract
Granulomatous inflammation in schistosomiasis is a consequence of T cell-mediated hypersensitivity to parasite egg Ag. In the present study we used three consecutive independent chromatographic procedures to fractionate and identify the soluble egg Ag recognized by schistosome-specific, cloned, murine, CD4+ Th1-type lymphocytes, which had been shown previously to be capable of mediating granuloma formation in vivo when adoptively transferred to normal syngeneic hosts challenged with an i.v. injection of eggs. The stimulatory activity resided in two acidic egg molecules, with apparent molecular masses of 64 to 68 kDa and 38 to 42 kDa, each of which ran as a single band on SDS-PAGE after purification. Fast performance liquid chromatography and SDS-PAGE performed under reducing conditions suggested that the two molecules are related and that the 38- to 42-kDa molecule is a subunit of the 64- to 68-kDa molecule. Polyclonal lymphoid cells from schistosome-infected mice were similarly stimulated by the purified 64- to 68-kDa and 38- to 42-kDa molecules, implying that these are sensitizing Ag in the natural disease.
Activation of human peripheral blood mononuclear cells by nitric oxide-generating compounds.
Authors: Lander H M , Sehajpal P , Levine D M , Novogrodsky A 
Published: December 2022

Abstract
Recent work in this laboratory has identified immune-stimulatory properties of the oxidant hemin. In this study, we examined whether the nitrogen-based oxidant nitric oxide (NO) had inductive effects on human lymphocytes. We found that the NO-generating compounds sodium nitroprusside and S-nitroso-N-acetylpenicillamine rapidly enhanced the rate of glucose transport in resting human PBMC. In addition, NF-kappa B binding activity was induced by these agents as was the secretion of TNF-alpha. The data suggest that a cGMP-independent mechanism is involved as the cell permeant cGMP analogue, 8-Br-cGMP, had no effect in eliciting these inductive events. Activation of lymphocytes by these NO-generating compounds may be mediated through the protein tyrosine phosphorylation signal transduction pathway. We found that membrane-associated protein tyrosine phosphatase activity was enhanced in PBMC treated with sodium nitroprusside or S-nitroso-N-acetylpenicillamine and that the src family protein tyrosine kinase p56lck was activated in these cells. Inasmuch as p56lck activity is negatively controlled by tyrosine phosphorylation, its activation may be related to the enhancement of protein tyrosine phosphatase activity. 8-Br-cGMP had no effect on these enzymes. Taken together, these data suggest that NO may have immune-stimulatory properties and may signal through a hitherto undescribed cGMP-independent pathway.
Control of exocytosis in early neutrophil activation.
Authors: Sengeløv H , Kjeldsen L , Borregaard N 
Published: December 2022

Abstract
Exocytosis of human neutrophil secretory vesicles, gelatinase granules, specific granules, and azurophil granules was measured during modulation of the intracellular free calcium concentration. A strict rank order of exocytosis of the four compartments was observed when cytosolic calcium was elevated by an ionophore in Fura-2-loaded cells. The rank order was: secretory vesicles, gelatinase granules, specific granules, and azurophil granules. Secretory vesicles were exceptionally sensitive to cytosolic free calcium, being completely mobilized after small cytosolic calcium transients. Kinetic studies with FMLP or ionomycin as stimulus showed that the same rank order was valid concerning the rate of exocytosis. In contrast to the other granules, a major part of the secretory vesicles were exocytosed after FMLP stimulation when intracellular calcium was chelated with bis-(2-amino-5-methylphenoxy)-ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester. These data indicate that, in contrast to other neutrophil granules, secretory vesicles are mobilized completely after small isolated elevations of cytosolic calcium. On the other hand, complete elimination of the FMLP-derived calcium transient does not inhibit exocytosis of secretory vesicles markedly. Thus, the effect of FMLP on secretory vesicles is signaled via cytosolic free calcium and an alternative pathway activated in parallel. This may be the basis for the unique position of this compartment as a readily mobilizable store of components important in early neutrophil activation.
Presentation of endogenous peptides to MHC class I-restricted cytotoxic T lymphocytes in transport deletion mutant T2 cells.
Authors: Zweerink H J , Gammon M C , Utz U , Sauma S Y , Harrer T , Hawkins J C , Johnson R P , Sirotina A , Hermes J D , Walker B D 
Published: December 2022

Abstract
The ability of minigene-encoded viral peptide epitopes to be presented by class I molecules in the absence of MHC-encoded transporters has been evaluated in mutant T2 cells. These cells have a large deletion in the class II MHC region that includes the known transporter protein for antigenic peptides and proteasome genes and they are defective in presenting viral epitopes to CTL. T2 cells that express minigenes encoding the influenza virus matrix peptide 58-66 (GILGFVFTL) and two HTLV 1 Tax peptides 11-19 (LLFGYPVYV) and 12-19 were lysed by HLA-A2-restricted peptide-specific CTL. Minigene expression of a HLA-A2-restricted HIV reverse transcriptase peptide 476-484 (ILKEPVHGV) with three charged residues sensitized T2 cells poorly for lysis by HIV-specific CTL unless the peptide was preceded by an endoplasmic reticulum translocation signal sequence. Expression of an influenza virus nucleoprotein peptide 383-391 (SRYWAIRTR) with three charged arginine residues did sensitize HLA-B27+ T2 cells for lysis by peptide-specific CTL. These and other results with endogenously expressed peptide analogs in which hydrophobic and charged amino acids were interchanged demonstrate that antigenic peptides can be translocated from the cytoplasm into the class I Ag presentation pathway independent of MHC-encoded transporters; and that peptide hydrophobicity appears not to be a major determinant in selecting peptides for this alternate pathway.
Protease treatment of nuclear extracts distinguishes between class II MHC X1 box DNA-binding proteins in wild-type and class II-deficient B cells.
Authors: Hasegawa S L , Riley J L , Sloan J H , Boss J M 
Published: December 2022

Abstract
The X box region is critical for directing the expression of class II major histocompatibility complex genes in B lymphocytes. Although several class II promoter-specific DNA binding factors have been described, only the X box region factor, RFX, shows a genetic correlation with class II expression, being deficient in some B cell lines derived from patients with class II-deficient congenital immunodeficiency. To further evaluate the role of X box DNA-binding proteins in class II gene expression, the role of the X box region was examined in both class II-positive and -negative lymphoid cells. In addition to the wild-type B cell line Raji, two class II transcriptional mutant cell lines, SJO and RJ2.2.5, and Jurkat, a class II negative T cell line, were examined. In contrast to wild-type B cells, neither of the class II mutant cell lines could use the X box region to direct the expression of a transiently transfected reporter gene, indicating that the X box-dependent transcriptional pathway is defective in these cells. The binding activity of the X1 box DNA-binding protein RFX was examined and found to be present in wild-type B cells and the mutant RJ2.2.5 but was absent in SJO and Jurkat. However, other X1 box-specific activities were detected in all these cell lines. To determine whether these different X1 box activities represented distinct DNA binding proteins or multimeric forms of the same factor(s), protease treatment of the crude nuclear extracts followed by DNA-binding assays were carried out and demonstrated that B cell extracts contain at least two X1-specific factors. One of these cleaved products (band 1 pk) correlates with RFX activity. A similar comparison with protease-treated extracts prepared from Jurkat cells demonstrated the presence of the band 1pk activity despite an absence of the native RFX activity. In contrast, protease treatment and analysis of SJO extracts showed no detectable levels of the band 1pk activity. These results demonstrate that multiple X1 box-specific DNA-binding activities exist in all lymphoid cells, but the presence of an actively binding RFX species correlates with class II transcription.
IL-4 attenuates the transcriptional activation of both IFN-alpha and IFN-gamma-induced cellular gene expression in monocytes and monocytic cell lines.
Authors: Larner A C , Petricoin E F , Nakagawa Y , Finbloom D S 
Published: December 2022

Abstract
The interaction of IFN-alpha and IFN-gamma with monocytes results in several actions that significantly influence the course of an immune response. Many of these effects are proinflammatory and can contribute to the degree of tissue injury at a site of inflammation. Whereas recent investigations target IL-4 as a T cell product that can antagonize some of the responses induced by IFN, little is known regarding the mechanisms involved. We have taken advantage of two well defined systems: the transcriptional activation of the cellular genes ISG-54 by IFN-alpha and IP-10 by IFN-gamma. IL-4 treatment of both the monocytic leukemia cell line, THP-1, and normal peripheral blood monocytes resulted in inhibition of IFN-induced RNA levels for both genes. Nuclear run-on assays in THP-1 cells indicated that the effects of IL-4 were due to the inhibition of the transcriptional activation of these genes by both IFN-alpha and IFN-gamma. This inhibition was not due to alteration in the binding characteristics of IFN-alpha or IFN-gamma to the cell. In the IFN-alpha system, we were able to show that IL-4 treatment resulted in reduced formation of the transcriptional activator, IFN-stimulated gene factor 3. This reduction appears to be the result of a defect in the ability of IFN alpha to activate the IFN-stimulated gene factor 3 alpha component of IFN-stimulated gene factor 3.
Lactate transport in macrophages.
Authors: Loike J D , Kaback E , Silverstein S C , Steinberg T H 
Published: December 2022

Abstract
Macrophages perform phagocytic and effector activities in a number of different tissues. The environment of the inflammatory foci in which they function is often acidic and contains an abundance of lactate. We characterized the ability of thioglycollate-elicited mouse peritoneal macrophages to accumulate lactate from the medium and to use this lactate to maintain intracellular energy stores. Lactate uptake was stereospecific for L-lactate and was inhibited by the organic anion transport blocker probenecid but not by concentrations of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid that block anion exchangers. L-[14C]Lactate uptake was not affected by variation of the extracellular Na+ concentration but was enhanced by acidification of the extracellular medium, suggesting that lactate uptake was mediated by a proton cotransport system. The enhanced accumulation of [14C]-lactate seen in medium at pH 6.0 to 6.5 was inhibited by probenecid or by an excess of unlabeled L-lactate. When macrophages were incubated in PBS without glucose for 6 h, intracellular stores of phosphocreatine were 13 nmol/mg of protein, compared with 44 nmol/mg of protein in cells incubated in medium containing glucose. When lactate was substituted for glucose, phosphocreatine stores were 32 nmol/mg of protein. These studies reveal that macrophages take up L-lactate in a pH-dependent manner and that lactate uptake occurs via a probenecid-inhibitable monocarboxylate transporter; they suggest that macrophages can utilize this lactate as an energy source.
Influence of nephrectomy on tumor necrosis factor clearance in a murine model.
Authors: Bemelmans M H , Gouma D J , Buurman W A 
Published: December 2022

Abstract
TNF, a cytokine with multiple properties, is known to be rapidly inactivated in vivo. In patients with septic shock and kidney malfunction, conflicting data have been reported regarding the presence of TNF in the circulation. Recently, we have shown that these differences can be the result of the detection of free TNF vs TNF complexed with soluble TNF-R. Enhanced levels of soluble TNF-R have been reported in patients with kidney malfunction. Because the kidney is thought to play an important role in TNF and TNF-R metabolism, we investigated the influence of bilateral nephrectomy on TNF clearance and TNF-R regulation in a murine model. The data obtained show that bilateral nephrectomy results in circulating levels of immunologically detectable (ELISA), but not biologically active (bioassay), TNF. Injection of endotoxin results in significantly higher levels of immunologically detectable TNF in bilaterally nephrectomized mice, compared with sham-operated mice, whereas biologically active levels were similar. To investigate the roles of TNF-R1 (P55) and TNF-R2 (P75) in this process, clearance of TNF was studied by injection of murine and human TNF. Murine TNF injection leads to comparable clearance of bioactive TNF in nephrectomized and sham-operated mice (t1/2 = approximately 12 min). However, clearance of immunologically detectable murine TNF is significantly slower in nephrectomized mice, compared with sham-operated mice (t1/2 = 96 min vs 26 min, respectively; p &lt; 0.05). Administration of human TNF results in a significantly lower clearance in nephrectomized mice, compared with sham-operated mice (t1/2 = 108 min vs 25 min, respectively; p &lt; 0.05). This is observed for both bioactive human TNF and immunologically detectable human TNF. Based on the fact that murine TNF-R1 (55 kDa) has a similar affinity for murine and human TNF, whereas murine TNF-R2 (75 kDa) shows affinity only for murine TNF, the data obtained suggest an important role for TNF-R2 in inactivation and clearance of TNF by the kidney. Moreover, the data suggest that kidney malfunction affects TNF clearance, leading to increased amounts of circulating TNF-TNF-R complexes, which could function as a slow release reservoir for TNF.
Differential usage of T cell receptor V gene segments in CD4+ and CD8+ subsets of T lymphocytes in monozygotic twins.
Authors: Hawes G E , Struyk L , van den Elsen P J 
Published: December 2022

Abstract
The TCR confers immunity by the specific recognition of foreign Ag peptides in the context of self-MHC molecules. The mechanisms controlling TCR selection and repertoire generation are not clearly understood and seem to occur in an apparently random, (self) Ag-driven manner. To address the question to what extent the TCR repertoire is randomly shaped or genetically predetermined, we have analyzed the alpha beta TCR repertoire of the CD4+ and CD8+ subsets of peripheral blood lymphocyte cultures of monozygotic twins by using the polymerase chain reaction technique with TCR V region gene family-specific oligonucleotide primers. Our studies demonstrate that there is high concordance in the overall patterns of V gene usage within a pair of twins, particularly in V beta usage (mean V beta CD4+ R2 = 0.869 and CD8+ R2 = 0.833) and to a lesser extent V alpha usage (mean V alpha CD4+ R2 = 0.621 and CD8+ R2 = 0.627); whereas the patterns between unrelated individuals show more variability. This study has also demonstrated that the V alpha and V beta genes are not randomly used within the CD4+ and CD8+ subsets. We observed significant preferential skewing of several V alpha or V beta gene families to either the CD4+ or CD8+ subset in the majority of individuals analyzed (p-value range = 0.0476 to &lt; 0.001). In particular, V alpha 11, 17, 22, and V beta 3, 9, 12, 18 were skewed to the CD4+ subset; whereas V alpha 2, 6, 12, 15, 20 and V beta 7, 14, 17 were skewed to the CD8+ subset. Furthermore, a number of the V genes showed patterns of skewing consistent only within a pair of twins. In three pairs of twins, V beta 2 was skewed to the CD4+ subset, whereas the fourth pair used almost equal frequencies of V beta 2 in both subsets. This observation was made for the V beta 2, 4, 5, 6, 8, 19 and V alpha 7, 16, 18, 21 families. Finally, the ratio of the relative V gene usage frequency that could be observed within an individual was conserved within the sets of twins; for instance, the relative amount of V beta 2 to that of V beta 3 was higher in both individuals of one set of twins, whereas it was lower in all of the other three sets. Together these observations suggest that the predominant influence shaping the TCR repertoire is genetically predetermined, of which, HLA-predicted selection mechanisms exerted during thymic maturation might be contributing factors.
Inhibition of cell adhesion by microspheres coated with recombinant soluble intercellular adhesion molecule-1.
Authors: Welder C A , Lee D H , Takei F 
Published: December 2022

Abstract
Murine recombinant soluble intercellular adhesion molecule-1 (sICAM-1) was produced and characterized. When immobilized on plastic microtiter wells, sICAM-1 efficiently mediated LFA-1-dependent cell adhesion, indicating that the purified protein retained the ability to bind to LFA-1. However, sICAM-1 in solution, at concentrations up to 100 micrograms/ml, was incapable of inhibiting the phorbol ester-induced homotypic aggregation of lymphocytes, the adhesion of T cells to plastic immobilized sICAM-1, and CTL effector function, all of which are mediated by intercellular adhesion molecule-1:LFA-1 interaction. In contrast, uniform polystyrene microspheres coated with sICAM-1 bound specifically to LFA-1+ cells and efficiently inhibited the adhesion of T cells to immobilized sICAM-1. The sICAM-1-coated microspheres also inhibited CTL function, but the inhibition was only partial. These results suggest that although monomeric sICAM-1 cannot competitively inhibit cell adhesion mediated by intercellular adhesion molecule-1 and LFA-1, microspheres coated with sICAM-1 can inhibit such cell adhesion.
HLA-DQ allelic polymorphisms constrain patterns of class II heterodimer formation.
Authors: Kwok W W , Kovats S , Thurtle P , Nepom G T 
Published: December 2022

Abstract
HLA-DQ class II molecules are complex heterodimers in which polymorphic alpha- and beta-polypeptides form noncovalent associations leading to cell surface expression. Using gene transfer with retroviral vectors, we demonstrate that surface expression of heterodimers among various DQ alpha and -beta polypeptides is not universal. Two types of allele-specific constraints were found: DQ beta chains that are associated with the DQw1 specificities do not form stable cell surface heterodimers with DQ alpha chains encoded on haplotypes that are associated with DQw2, DQw3, or DQw4. Similarly, surface expression of heterodimers composed of DQw2- or DQw3-associated DQ beta chains and DQw1 DQ alpha chains were not detected. The formation of mixed isotype heterodimers also showed allelic preference: DR alpha/DQw1 beta dimers were detected on the cell surface, but DR alpha/DQw3 beta dimers were not. Failure to express class II heterodimers on the cell surface was apparently due to either inefficient assembly of the alpha- and beta-chains or retention of the mismatched dimers in an intracellular compartment. DQ beta cDNA encoding DQw1- and DQw3-associated beta-polypeptides were modified to create chimeric expression vectors in which portions of the DQ beta polypeptides were exchanged between different alleles. The resulting chimeric DQ beta polypeptides were tested for their ability to form stable heterodimers with different DQ alpha polypeptides. A cluster of polymorphic amino acid residues encoded by the 3' end of the DQB1 second exon, corresponding to residues 60 to 91 in the DQ beta polypeptide, were found to be critical determinants constraining stable cell surface heterodimer formation among preferential alpha- and beta-combinations.