bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of intercellular adhesion molecule-1 (ICAM-1)-augmented degranulation by cytotoxic T cells. ICAM-1 and anti-CD3 must be co-localized for optimal adhesion and stimulation.
Authors: Berg N N , Ostergaard H L 
Published: December 2022

Abstract
Purified intercellular adhesion molecule-1 (ICAM-1), a ligand of the LFA-1, was used to analyze the contribution of ICAM-1 to the activation of CTL. ICAM-1 facilitates degranulation when co-immobilized with substimulatory amounts of anti-CD3. This facilitated response is most likely mediated through LFA-1, since Abs to this molecule significantly inhibit the response, Interestingly, when ICAM-1 and anti-CD3 are immobilized on separate beads and presented to the CTL, no ICAM-1-enhanced degranulation is observed. The ICAM-1 and anti-CD3 must be immobilized on the same surface to augment the response, suggesting that ICAM-1 either does not transmit signals into the cell or it transmits a very localized signal, since the ICAM-1 and anti-CD3 must be juxtaposed. Consistent with this finding, we demonstrate that ICAM-1 does not induce tyrosine phosphorylation or a Ca(2+)-flux in the CTL clone, but does potentiate these responses when co-immobilized with substimulatory anti-CD3. Finally ICAM-1 and anti-CD3 must be immobilized on the same bead for stable adhesion of CTL to ICAM-1. When ICAM-1 and anti-CD3 are immobilized on separate beads, there is only a transient, low level of adhesion to the ICAM-1 beads. Taken together, these results suggest that LFA-1 is acting principally as an adhesion molecule, with respect to ICAM-1, in CTL and that this adhesion is regulated through the TCR complex.
Lysosome-associated membrane protein-1-mediated targeting of the HIV-1 envelope protein to an endosomal/lysosomal compartment enhances its presentation to MHC class II-restricted T cells.
Authors: Rowell J F , Ruff A L , Guarnieri F G , Staveley-O'Carroll K , Lin X , Tang J , August J T , Siliciano R F 
Published: December 2022

Abstract
A subset of endogenously synthesized Ags can be processed for class II-restricted presentation, probably through multiple mechanisms. Processing of exogenous Ags for class II-restricted presentation appears to occur in unique endosomal processing compartments with lysosomal characteristics including the presence of the lysosomal membrane protein LAMP-1. Therefore, we attempted to enhance the efficiency of class II-restricted presentation of an endogenous Ag, the HIV-1 envelope (env) protein, by specifically targeting the Ag to class II processing compartments through the pathway followed by LAMP-1. Because the env protein associates tightly with CD4 shortly after synthesis, we first targeted the env protein using a chimeric CD4 protein consisting of the extracellular domain of CD4 and the transmembrane and cytoplasmic domains of LAMP-1. When co-expressed with this chimeric protein, the env protein was efficiently localized to lysosome-like compartments. Enhanced stimulation of env-specific CD4+ T cell clones by APC expressing the env protein and the CD4-LAMP-1 chimera was readily demonstrated in both cytotoxicity assays and proliferation assays. We also targeted the env protein directly as a chimeric protein consisting of the extracellular domain of the env protein and the transmembrane and cytoplasmic domains of LAMP-1. The proliferative response of env-specific CD4+ T cell clones to the env-LAMP-1 chimera was greatly enhanced compared with wild-type env protein, especially when limiting numbers of stimulator cells were used. The enhanced stimulatory capacity of APC expressing LAMP-1-targeted Ags has important implications for vaccine design.
Differential regulation of alternative 3' splicing of epsilon messenger RNA variants.
Authors: Diaz-Sanchez D , Zhang K , Nutman T B , Saxon A 
Published: December 2022

Abstract
Alternative 3' splicing of the one active human epsilon heavy chain gene results in variants of epsilon mRNA encoding distinct IgE proteins. The same relative amounts of these epsilon mRNA variants were produced by non-atopic donor B cells when driven in a variety of T-dependent or T-independent systems. The most abundant variants were those for classic secreted epsilon a novel secreted form (CH4-M2"). In contrast, cells from subjects with high levels of serum IgE secondary to parasitic infection or atopy spontaneously produced higher relative levels of the CH4-M2' epsilon mRNA variant, lower relative amounts of both the membrane and CH4-M2" secreted variants, and very low levels of the CH4'-CH5 variant. The existence of and corresponding changes in levels of the CH4-M2'-encoded secreted protein were demonstrated. IL-10 induced this same differential expression of epsilon splice variants in vitro when used to costimulate IL-4 plus CD40-driven B cells and could differentially enhance the production of CH4-M2' protein by established IgE-secreting cell lines. Inhibition of IgE by cross-linking the low affinity IgE receptor (CD23) decreased the levels of epsilon mRNA and resulted in a distinct pattern of epsilon mRNA characterized by a dramatic decrease in CH4-M2' splice variant. IL-6, IL-2, or IFN-gamma did not change the epsilon mRNA pattern. Overall, the absolute and relative amounts of the different epsilon mRNA splice variants produced appear to be controlled in a differentiation-related fashion.
Expression cloning and chromosomal mapping of the leukocyte activation antigen CD97, a new seven-span transmembrane molecule of the secretion receptor superfamily with an unusual extracellular domain.
Authors: Hamann J , Eichler W , Hamann D , Kerstens H M , Poddighe P J , Hoovers J M , Hartmann E , Strauss M , van Lier R A 
Published: December 2022

Abstract
CD97 is a monomeric glycoprotein of 75 to 85 kDa that is induced rapidly on the surface of most leukocytes upon activation. We herein report the isolation of a cDNA encoding human CD97 by expression cloning in COS cells. The 3-kb cDNA clone encodes a mature polypeptide chain of 722 amino acids with a predicted molecular mass of 79 kDa. Within the C-terminal part of the protein, a region with seven hydrophobic segments was identified, suggesting that CD97 is a seven-span transmembrane molecule. Sequence comparison indicates that CD97 is the first leukocyte Ag in a recently described superfamily that includes the receptors for secretin, calcitonin, and other mammalian and insect peptide hormones. Different from these receptors, CD97 has an extended extracellular region of 433 amino acids that possesses three N-terminal epidermal growth factor-like domains, two of them with a calcium-binding site, and a single Arg-Gly-Asp (RGD) motif. The existence of structural elements characteristic for extracellular matrix proteins in a seven-span transmembrane molecule makes CD97 a receptor potentially involved in both adhesion and signaling processes early after leukocyte activation. The gene encoding CD97 is localized on chromosome 19 (19p13.12-13.2).
Activation of IL-2 receptor alpha-chain gene by individual members of the rel oncogene family in association with serum response factor.
Authors: Pierce J W , Jamieson C A , Ross J L , Sen R 
Published: December 2022

Abstract
Expression of the IL-2R alpha gene is regulated by members of the c-Rel/NF-kappa B family of transcription factors binding to the kappa B site in the promoter. Previous work has not defined the role of individual members of the c-Rel family in the activation of the IL-2R alpha gene. Using the COS cell system, we were able to reconstitute the regulation of the IL-2R alpha promoter by expressing cloned Rel family members with serum response factor (SRF). We found that c-rel alone activated the IL-2R alpha promoter only weakly but worked with the p50 subunit of NF-kappa B (NFKB1) to give a higher level of expression. We showed that c-rel heterodimerizes with p50 and the amount of this heterodimer correlated with the level of IL-2R alpha gene expression. Our results provide evidence that c-rel/p50 heterodimers activate gene expression in the context of a cellular promoter. We show that c-rel or p65 can cooperate with SRF in the activation of this promoter and the transactivation by c-rel with SRF was enhanced by p50. Synergistic activation required both kappa B and CArG sites, and binding studies show that these adjacent sites can be occupied simultaneously. The transactivation observed with cloned transcription factors mimics the physiologic induction of the IL-2R alpha gene since multiple sequence elements cooperate to give gene activation. The data support the model that c-rel/p50 or p65 can cooperate with SRF to specifically target the expression of the IL-2R alpha gene in activated T cells.
Differences in the shedding of soluble TNF receptors between endotoxin-sensitive and endotoxin-resistant mice in response to lipopolysaccharide or live bacterial challenge.
Authors: Carpenter A , Evans T J , Buurman W A , Bemelmans M H , Moyes D , Cohen J 
Published: December 2022

Abstract
TNF-alpha plays a pivotal role in the pathogenesis of septic shock. It exerts its effects by binding two cell surface receptors, designated TNF-R I and II, also referred to as the p55 and p75 receptors, respectively. TNF-Rs are transmembrane proteins, which on cleavage of their extracellular domains, result in the release of soluble fragments (sTNF-R). sTNF-R levels increase markedly during infection, and may serve to modulate TNF-alpha bioactivity. The mechanisms regulating this process are uncertain. To investigate this, we measured sTNF-R release in endotoxin-sensitive C3H/HeN and endotoxin-resistant C3H/HeJ mice given LPS or live Gram-negative bacteria. In C3H/HeN mice, there was a rapid early response during the first 4 h, and a second peak at 8 h, particularly noticeable in the case of the p75 receptor. Prior administration of neutralizing Abs to TNF-alpha or IFN-gamma had no effect on receptor shedding. Surprisingly, C3H/HeJ mice also responded to both bacterial challenge and to LPS by shedding sTNF-R; the magnitude and duration of the early response was not substantially different from C3H/HeN mice, although the second peak was absent. Peritoneal macrophages from C3H/HeN mice responded promptly (5 h) when stimulated with LPS in vitro, and by 22 h levels had increased five- to 10-fold. In contrast, cells from C3H/HeJ mice demonstrated only a very modest response at 22 h following maximal stimulation. The data suggest that there may be at least two separately regulated pathways that control sTNF-R shedding in these mice.
Defective ceramide response in C3H/HeJ (Lpsd) macrophages.
Authors: Barber S A , Perera P Y , Vogel S N 
Published: December 2022

Abstract
Lipid second messengers are gaining recognition as important mediators of extracellular signals. One such lipid, ceramide, generated from membrane sphingomyelin following stimulation with TNF-alpha, IL-1 beta, or IFN-gamma, activates ceramide-activated kinase (CAK). A recent study demonstrated that LPS activated CAK without generating ceramide, suggesting that the LPS stimulation of cells mimics the second messenger function of ceramide. To compare ceramide to LPS signaling, we assessed the ability of LPS-responsive (Lpsn) and LPS-hyporesponsive (Lpsd) macrophages to respond directly to ceramide for enhanced expression of LPS-inducible genes. In contrast to macrophages from C3H/Ouj (Lpsn) mice, C3H/Hej (Lpsd) macrophages failed to respond to cellpermeable analogues of ceramide (C2,C6,C16) or sphingomyelinase. These results suggest that a common critical molecule, encoded by the Lps gene, regulates both ceramide and LPS signaling pathways.
Decreased binding of specific monomeric and trimeric G-proteins with the plasma membrane of polymorphonuclear leukocytes exposed to influenza A virus.
Authors: Abramson J S , Hudnor H R 
Published: December 2022

Abstract
Influenza A virus (IAV)-induced polymorphonuclear leukocyte (pMNL) dysfunction is important in causing secondary bacterial infections that lead to most influenza-related deaths. We previously showed that PMNLs exposed to IAV followed by a variety of stimuli (e.g., FMLP, PMA) demonstrate inhibition of various activation steps and endstage functions, suggesting IAV alters an early step in cell signalling. The present study examined IAV's effect on trimeric and monomeric G-proteins, since alterations of these proteins could explain IAV-induced PMNL dysfunction to various stimuli. PMNLs exposed to IAV for 30 min had decreased membrane-associated basal and high affinity guanosine triphosphatase (GTPase) activity compared with control cells. immunoblotting studies, using trimeric G-protein alpha and beta subunit-specific Abs, showed IAV decreased plasma membrane association of the trimeric G-proteins alpha subunits Gi2 and Gq by 33% +/- 5 and 46% +/- 8, respectively; binding of Gi3 and Gs was not altered. Similar studies involving monomeric G-proteins demonstrated that IAV decreased the membrane binding of rap1A (35% +/- 4), but not rac G-proteins. Corresponding increases in these IAV-altered G-proteins were detected in intracellular compartments. These data suggest the mechanism of IAV-induced PMNL dysfunction involves alterations in the binding of trimeric and monomeric G-proteins to plasma membranes.
Peptidoglycan induces transcription and secretion of TNF-alpha and activation of lyn, extracellular signal-regulated kinase, and rsk signal transduction proteins in mouse macrophages.
Authors: Gupta D , Jin Y P , Dziarski R 
Published: December 2022

Abstract
In soluble peptidoglycan (PGN) from staphylococcal cell walls as well as soluble PGN (sPGN) secreted by staphylococci in the presence of beta-lactam antibiotics induced TNF-alpha mRNA and secretion of bioactive TNF-alpha in the murine RAW264.7 macrophage cell line, PGN and sPGN also induced rapid and dose-dependent tyrosine phosphorylation of several cellular proteins, including lyn and mitogen-activated protein kinases (extracellular signal-regulated kinases; but not hck, fgr, or vav) and increased the activities of mitogen-activated protein and rsk kinases. These PGN- and sPGN-induced effects were qualitatively similar to the effects induced by ReLPS, but higher concentrations of PGN and sPGN than ReLPS were required. In contrast to the ReLPS-induced effects, the PGN- and sPGN-induced effects were not inhibited by polymyxin B. All PGN-, sPGN-, and ReLPS-induced effects were serum independent, since they were observed both in RAW264.7 cells grown and stimulated in the presence of serum and in the cells adapted to growth and stimulated in a serum- and albumin-free medium. These results indicate that lyn, extracellular signal-regulated kinase, and rsk signal transduction molecules may be involved in macrophage activation by PGN and further support the idea that PGN and LPS may activate the cells through similar mechanisms.
IL-13 expression at the sites of allergen challenge in patients with asthma.
Authors: Huang S K , Xiao H Q , Kleine-Tebbe J , Paciotti G , Marsh D G , Lichtenstein L M , Liu M C 
Published: December 2022

Abstract
Atopic asthma is characterized by inflammatory responses of the airway and is associated with up-regulation of Th2 cytokines, notably IL-4 and IL-5. A recently described human cytokine, IL-13, is a potent in vitro modulator of various cell types, including monocytes, B cells, and endothelial cells. Similar to IL-4, it is also involved in the induction of IgE synthesis. However, the in vivo expression and function of IL-13 and its relation to disease remain to be defined. Using a segmental allergen challenge model, we have examined the in vivo expression of IL-13 in the bronchoalveolar lavage (BAL) cells of atopic patients. We found a significant enhancement of both IL-13 transcripts and secreted proteins in the allergen-challenged BAL compared with the saline-challenged control sites of asthmatic and rhinitic patients. In contrast, the expression of IL-13 transcripts was not detected in the BAL of two normal subjects challenged with the same dose of ragweed allergen. The cellular source of IL-13 mRNA was identified in the mononuclear cell fraction of the allergen-challenged BAL. The allergen-induced quantitative differences in the level of transcripts were confirmed by competitive PCR assays. These results suggest that the significant increase in IL-13 in the allergen-challenged BAL is primarily from the mononuclear cells and is involved in the regulation of allergen-induced late phase inflammatory responses.
T and B cell collaboration is essential for the autoantibody response to DNA topoisomerase I in systemic sclerosis.
Authors: Kuwana M , Medsger T A , Wright T M 
Published: December 2022

Abstract
To elucidate the mechanisms controlling anti-DNA topoisomerase I (topo I) antibody production in patients with systemic sclerosis (SSc), in particular the role of interactions between topo I-specific Th cells and B cells, we established an in vitro system for the analysis of anti-topo I antibody production. In vitro anti-topo I antibody synthesis in PBMC cultures was induced by recombinant topo I and PWM, and was measured by a topo I-specific ELISA. Anti-topo I antibody was detected in PBMC culture supernatants from 11 (61%) of 18 anti-topo I-positive SSc patients. In contrast, anti-topo I antibody was not detected in the PBMC culture supernatants from 4 anti-topo I-negative SSc patients or 10 healthy donors. Characterization of in vitro anti-topo I antibody production showed that 1) the anti-topo I antibody isotype produced was IgG; 2) the anti-topo I antibody levels in culture supernatants correlated with those in patients' sera; 3) CD4+ T cells were necessary for antibody synthesis; and 4) antibody synthesis was restricted by HLA-DR, but not by HLA-DQ or DP. In addition, separation of cultured T and B cells by a semipermeable membrane or culture with anti-CD40 ligand mAb blocked in vitro anti-topo I antibody production. These results indicate that a contact-mediated and HLA-DR-restricted collaboration between topo I-specific T and B cells is essential for in vitro anti-topo I antibody production in a subset of SSc patients.
Characterization of a major latex allergen associated with hypersensitivity in spina bifida patients.
Authors: Lu L J , Kurup V P , Hoffman D R , Kelly K J , Murali P S , Fink J N 
Published: December 2022

Abstract
Hypersensitivity to latex proteins present in health care products, particularly in latex gloves, has emerged as an important public health problem in recent years. Most of these latex allergens have not been purified or characterized. Here we report the purification and characterization of a 23-kDa latex polypeptide from nonammoniated natural rubber latex. This purified 23-kDa polypeptide reacted with IgE from 13 of 17 (76%) latex-allergic spina bifida patients, but from only 1 of 5 health care workers with latex allergy. Furthermore, all the sera of patients with anaphylaxis to latex showed reactivity with the 23-kDa polypeptide. This allergen also induced significant lymphocyte proliferation by PBMC from spina bifida patients, but not from health care workers. The 90 amino acid residues sequenced from the 23-kDa polypeptide showed a 45.6% homology with a previously reported latex protein, rubber elongation factor. By using a mAb LAM-1, produced against the 23-kDa allergen, we could also detect this allergen or its epitope in ammoniated latex and natural rubber latex products used in health care management, but not in non-latex extracts studied.
HIV predominantly induces IL-1 receptor antagonist over IL-1 synthesis in human primary monocytes.
Authors: Zavala F , Rimaniol A C , Boussin F , Dormont D , Bach J F , Descamps-Latscha B 
Published: December 2022

Abstract
Interaction of HIV with cultured human monocytes triggers not only cytokine production but also the release of natural cytokine inhibitors such as the soluble TNF receptors, levels of which are increased in the circulation of HIV-infected patients. We found that HIV-1 LAI induced the production by human monocytes from HIV-seronegative donors of another type cytokine inhibitor, the IL-1Ra receptor antagonist (IL-1Ra). HIV mainly induced the secreted form (83%) of IL-1Ra through de novo mRNA synthesis. IL-1Ra production was triggered at an early step of the infection process and involved the HIV envelope protein and the CD4 receptor. HIV-triggered IL-1Ra production occurred after a lag time, suggesting an indirect mechanism. Neutralizing Abs to IL-1 beta and IL-10 had no effect, while simultaneous treatment with anti-TNF-alpha, anti-granulocyte-macrophage CSF, and anti-TGF-beta nearly abrogated IL-1Ra release, supporting an indirect induction through the concerted action of the co-produced cytokines. IL-1Ra was induced by HIV in a mean 1,000-fold increase over IL-1 alpha beta, a ratio 20-fold higher than that obtained with LPS. This production masked 80% of IL-1 bioactivity in HIV-induced monocyte supernatants. These results suggest that the net balance between pro-inflammatory cytokines and their natural inhibitors could be critical in the control of the inflammatory process associated with HIV infection.
Extrathymic maturation of alpha beta T cells from hemopoietic stem cells.
Authors: Dejbakhsh-Jones S , Jerabek L , Weissman I L , Strober S 
Published: December 2022

Abstract
The object of the study was to determine whether alpha beta T cells can develop from hemopoietic stem cells in the absence of the thymus. C57BL/6 (Ly-5.1 and Thy-1.2) mice were thymectomized or sham-thymectomized at 4 wk of age, and received lethal whole body irradiation 2 wk later. These mice were reconstituted with an i.v. injection of 500 highly purified hemopoietic stem cells (Mac-1-, B220-, TER-119-, CD3-, CD4-, CD8-, Thy 1low, SCA-1+) obtained from the bone marrow of C57BL/6 (Ly-5.2 and Thy-1.1) donors. A similar percentage of Ly-5.2+ alpha beta T cells (donor) was found in the marrow of thymectomized recipients, sham-thymectomized recipients, and normal donor mice at least 3 mo after stem cell transplantation. The percentage of Ly-5.2+ alpha beta T cells in the spleens of sham-thymectomized and normal donor mice was similar. The percentage in the spleens of thymectomized recipients was reduced by about 50%, and approximately one-half of the latter T cells expressed the CD4-CD8- alpha beta+ phenotype. A purified population of Ly-5.2+ alpha beta- cells obtained from the marrow of thymectomized recipients was incubated in vitro for 48 h without exogenous growth factors. After the incubation procedure a proportion of the marrow cells acquired alpha beta TCR surface receptors. The results show that alpha beta T cells can develop from hemopoietic stem cells in the absence of the thymus.
Activation and interaction with protein kinase C of a cytoplasmic tyrosine kinase, Itk/Tsk/Emt, on Fc epsilon RI cross-linking on mast cells.
Authors: Kawakami Y , Yao L , Tashiro M , Gibson S , Mills G B , Kawakami T 
Published: December 2022

Abstract
Cross-linking of the high-affinity IgE receptor (Fc epsilon RI) on mast cells induces rapid phosphorylation on serine, threonine, and tyrosine residues and increases the enzymatic activity, of a Tec subfamily tyrosine kinase, Itk/Tsk/Emt (Emt). The pleckstrin homology domain of Emt at its amino-terminal interacts directly with multiple isoforms of protein kinase C (PKC) in vitro. In addition, a portion of Emt is physically associated with multiple isoforms of PKC in intact mast cells. PKC phosphorylates a bacterial fusion protein containing the pleckstrin homology domain of Emt in vitro. Coexpression of Emt in COS-7 cells with Ca(2+)-dependent PKC isoforms (alpha, beta I, or beta II) induces an enhancement in tyrosine phosphorylation of Emt. In vivo inhibition of PKC expression or activity attenuates tyrosine phosphorylation and enzymatic activity of Emt induced upon Fc epsilon RI cross-linking. These data collectively suggest that PKC phosphorylates Emt and activates its autophosphorylating activity. Alternatively, PKC could activate another tyrosine kinase that phosphorylates Emt, or PKC-mediated phosphorylation of Emt may render it a target for another tyrosine kinase. In any case, PKC appears to play a major role in the activation of Emt induced upon Fc epsilon RI cross-linking.