bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphorylation of complement component C3 and C3 fragments by a human platelet protein kinase. Inhibition of factor I-mediated cleavage of C3b.
Authors: Ekdahl K N , Nilsson B 
Published: December 2022

Abstract
Phosphorylation of C3 in vitro has been shown previously to lead to significantly altered function of the protein. Platelets are known to contain and release considerable amounts of protein kinases and ATP, which are prerequisites for protein phosphorylation. The aim of the present study was to investigate whether C3 is phosphorylated extracellularly by human platelets. Platelet-rich plasma was stimulated by human aggregated gamma-globulin or ADP. The remaining cells were removed by centrifugation, and the plasma was incubated with [gamma-32P]ATP. After precipitation with Sepharose-bound Abs to C3c followed by SDS-PAGE, it was shown that C3 was phosphorylated in the alpha-chain by a protein kinase dependent on Mn2+, Ca2+, or Mg2+ ions. The supernatant from washed, activated platelets was incubated with purified C3 or soluble or activated thiol Sepharose-bound C3b, together with [gamma-32P]ATP. Phosphorylation was seen in the alpha-chain of C3, and to the same extent in the alpha'-chain of both C3b preparations. The analysis of acid hydrolysate demonstrated that C3 contained 32P-labeled Thr and 32P-labeled Ser. After extensive proteolysis with trypsin, the major phosphorylation site was located to a peptide of 3 to 4 kDa that was bound to the activated thiol Sepharose via the free sulphydryl group in the C3d fragment. Incubation of phosphorylated C3b with factors I and H showed that phosphorylation inhibited the cleavage of the alpha'-chain of C3b. The results in this study suggest that phosphorylation is a regulator of C3 during platelet activation induced, for example, by immune complexes.
Recombinant soluble CD14 prevents mortality in mice treated with endotoxin (lipopolysaccharide).
Authors: Haziot A , Rong G W , Lin X Y , Silver J , Goyert S M 
Published: December 2022

Abstract
Endotoxic shock is a life-threatening condition mediated by cytokines released after exposure to bacterial LPS/endotoxin. Activation of monocytes and neutrophils by the binding of LPS to the membrane receptor, CD14, plays a key role in this response. Furthermore, a soluble form of the CD14 receptor enhances the endothelial cell response to LPS. We show here that despite the agonist effects of soluble CD14 on the endothelial cell response to LPS, recombinant soluble CD14 is able to protect mice from LPS-induced lethality. This protection appears to be associated with the inhibition of TNF-alpha release. These results suggest that the soluble CD14 receptor may represent a new form of therapy for endotoxic shock in humans.
IFN-gamma and TNF-alpha induce redistribution of PECAM-1 (CD31) on human endothelial cells.
Authors: Romer L H , McLean N V , Yan H C , Daise M , Sun J , DeLisser H M 
Published: December 2022

Abstract
Platelet endothelial adhesion molecule-1 (PECAM-1/CD31) is a glycoprotein adhesion molecule of the Ig superfamily that is constitutively expressed on leukocytes, platelets, and endothelial cells where it concentrates at the intercellular borders of adjacent cells. Recent studies have confirmed that endothelial PECAM-1 is involved in the recruitment of neutrophils into inflammatory sites. However, the effects of inflammatory cytokines such as TNF-alpha and IFN-gamma on endothelial PECAM-1 expression are not known. We studied the effect of several inflammatory cytokines on human umbilical vein endothelial cell PECAM-1 expression. We found that TNF-alpha and IFN-gamma produced dose-dependent changes in the surface distribution of PECAM-1, with a loss of the typical staining of PECAM-1 at intercellular junctions. Because TNF-alpha and IFN-gamma did not alter PECAM-1 transcription or total surface PECAM-1, these changes in PECAM-1 localization are most consistent with a redistribution of the protein away from intercellular junctions. This cytokine-induced surface redistribution of PECAM-1 was associated with changes in PECAM-1 cytoskeletal association but did not involve the expression of different alternatively spliced variants of the molecule. Given the involvement of endothelial PECAM-1 in neutrophil recruitment, redistribution of PECAM-1 may serve as a mechanism for regulating the transmigration of leukocytes across the vascular endothelium.
Differences in the degree of depletion, rate of recovery, and the preferential elimination of naive CD4+ T cells by anti-CD4 monoclonal antibody (GK1.5) in young and aged mice.
Authors: Rice J C , Bucy R P 
Published: December 2022

Abstract
We compared the degrees of depletion and the rates of recovery of CD4+ T cells in young and old mice given a single injection of an anti-CD4 (GK1.5) mAb. We found that in young mice the CD4+ population of T cells was completely depleted from the peripheral blood and, subsequently, the lymph nodes and spleen. Young mice recovered 80% of CD4+ T cells within 100 days after the injection. Although aged mice have less CD4+ T cells, CD4+ T cells were depleted by only 60% after mAb injection. This finding was associated with prolonged circulation of Ab-coated T cells. The rate of repopulation of peripheral CD4+ T cells was also affected by aging, because 5 times less CD4+ T cells appear in aged than in young mice between days 14 and 100 post injection. Further, we found that the CD4+ T cells that are depleted in both young and old mice by injection of anti-CD4 mAb are CD45RBhigh, suggesting a preferential depletion of immature cells. Finally, the thymus appears to be required to repopulate the T cell population post injection, because thymectomized young mice failed to recover CD3+CD4+ cells.
Presentation of endogenous and exogenous antigens is not affected by inactivation of E1 ubiquitin-activating enzyme in temperature-sensitive cell lines.
Authors: Cox J H , Galardy P , Bennink J R , Yewdell J W 
Published: December 2022

Abstract
Little is known regarding the mechanism by which MHC class I-associated peptides are generated. Proteins can be targeted for degradation by the covalent attachment of ubiquitin. The first step in ubiquitin conjugation to proteins is its binding to E1 ubiquitin-activating enzyme. To study the role of ubiquitin-targeted protein degradation in Ag processing, we used two mutant cell lines with temperature-sensitive E1 proteins, and a recombinant vaccinia virus expressing wild-type human E1. One of the cell lines examined (hamster ts20 cells) was previously reported to have a minimal capacity after a 1-h incubation at 41 degrees C to present osmotically loaded OVA to a T cell hybridoma, as assessed by IL-2 release. Even after incubating the same cells for 1 h at 43 degrees C, we failed to detect an E1-related decrease in the presentation of biosynthesized or osmotically loaded OVA to splenic T cells, as measured by target cell lysis. We introduce the use of mouse tsA1S9 cells to Ag-processing studies and provide the initial biochemical characterization of their defect in protein ubiquitination. Relative to parental L929 cells, after thermal inactivation of E1, these cells actually demonstrate enhanced presentation of endogenous or exogenous viral Ags to T cells. Our findings do not support a role for protein ubiquitination in Ag processing, and indicate that either the temperature-sensitive cell lines examined do not exhibit a sufficient reduction in ubiquitin-conjugating activity to affect the generation of antigenic peptides, or that ubiquitin-targeted proteolysis is not essential for processing the two exogenous and six endogenous Ags examined.
Nonresponders to hepatitis B vaccine can present envelope particles to T lymphocytes.
Authors: Desombere I , Hauser P , Rossau R , Paradijs J , Leroux-Roels G 
Published: December 2022

Abstract
The mechanisms causing nonresponsiveness to hepatitis B surface Ag (HBsAg) vaccines in humans remain largely unknown. The increased incidence of nonresponsiveness in subjects with HLA-DR3 or -DR7 haplotype suggests that immune response mechanisms governed by genes of the MHC are involved. It is conceivable that APC of nonresponders are defective in the presentation of HBsAg because they are unable to adequately take up, process, or present this Ag. To examine this hypothesis we have used PBMC from nonresponders to present recombinant particles containing S or PreS2-S sequences to HBsAg-specific T cell lines from haplo-identical responder vaccinees. The proliferative response of these lines was used to evaluate the efficacy of Ag presentation. Unfractionated PBMC from five DR2+ and six DR7+ nonresponders did not proliferate to HBsAg in vitro, whereas they vigorously proliferated upon stimulation with tetanus toxoid, thus ruling out the presence of a generalized immunodeficiency. All DR2(15)+ nonresponders were able to present hepatitis B envelope Ag to HBsAg-specific, DR1501-restricted T cells. PBMC from six DR7+ nonresponders were all able to present HBsAg to DR07-restricted T cell lines and PBMC from three DPw4+ nonresponders were able to present HBsAg to DP0402-restricted T cell lines. Additional experiments showed that PBMC from two nonresponders presented HBsAg equally well and sometimes better than PBMC from two partially HLA-matched high responders. We conclude that HLA-DR2+, -DR7+, and -DPw4+ nonresponder vaccinees are able to take up, process and present HBsAg to allogeneic, haplo-identical T cell lines in vitro.
Murine T and B cell responses to natural and recombinant hornet venom allergen Dol m 5.02 and its recombinant fragments.
Authors: King T P , Kochoumian L , Lu G 
Published: December 2022

Abstract
White-face hornet venom allergen, Dol m 5.02, is a protein of 204 amino acid residues. This protein and its overlapping fragments, of 53-114 residues in size, containing the N-terminal, middle, and C-terminal regions of the molecule, can be expressed in high yield in bacteria by using the plasmid vector pQE12. Natural (n) and recombinant (r) Dol m 5.02s and the r-fragments are about equally immunogenic for IgG Ab response in BALB/c mice. n-Dol m 5.02 induces mainly murine IgG Abs specific for its discontinuous B cell epitopes and, to a lesser extent, Abs specific for its continuous epitopes. r-Dol m 5.02 and the r-fragments induce only Abs specific for continuous B cell epitopes that are common with those of the n-protein. Abs specific for the discontinuous epitopes show higher affinity than those specific for the continuous epitopes. r-Dol m 5.02 and the r-fragments are as efficient as n-Dol m 5.02 in inducing murine T cell responses specific for the n-protein. The differences in the immunogenicity of n- and r-proteins or r-peptide fragments for B and T cell responses are related to their conformations, inasmuch as only the n-protein is cross-linked by four disulfide bonds. These findings are relevant to the potential use of r-fragments as immunotherapeutic reagents in humans.
In vivo state of antiviral CTL precursors. Characterization of a cycling cell population containing CTL precursors in immune mice.
Authors: Razvi E S , Welsh R M , McFarland H I 
Published: December 2022

Abstract
The in vivo state of CD8+ mouse memory CTL specific to lymphocytic choriomeningitis virus (LCMV) was characterized. During acute LCMV infection, the majority of the LCMV-specific CTL activity tested immediately ex vivo was mediated by CD8+ L-selectin- Mac-1+ CTL. The L-selectin- population of CD8+ cells elicited during acute infection also carried &gt; 99% of the restimulatable CD8+ CTL precursors (CTLp) to LCMV, and these required added IL-2 for development into effectors in vitro. In contrast with the acute infection, most of the virus-specific CTLp in immune mice were L-selectin+. Examination of CD8+ T cells in LCMV-immune mice revealed that a L-selectin+ blast-size population of cycling CD8+ cells contained CTLp, which developed into effector CTL in the absence of added IL-2. These cells also expressed Mac-1 and IL-2R. Flow cytometric sorting for IL-2R+ and IL-2R- CD8+ cells in the immune animal revealed, by limiting dilution analysis, similar frequencies of CTLp in both populations. In bulk restimulation assays, the CD25+ CTLp did not require added IL-2 for their in vitro development into effectors, whereas the CD25- CTLp did. Hence, the different requirements for CTLp to effector development in vitro reflect qualitative differences in the in vivo state of the CTLp in the various subpopulations. LCMV-specific memory CTLp that did not require added IL-2 for differentiation were also found in the small-size, noncycling, CD8+L-selectin- cells. In contrast, the small-size, noncycling, CD8+L-selectin+, and CD8+IL-2R- populations also carried CTLp, but these required added IL-2 for development into effector CTL. Hence, T cell memory to LCMV is distributed among various lymphocyte subpopulations in immune animals, and the presence of an activated cycling cell component may account for the long-term perpetuation of antiviral immunologic memory.
Diversity of V gamma gene segments rearranged to the J gamma 4 gene in mice.
Authors: Atsuta N , Nishimura H , Nakamura N , Emoto M , Iwatsuki T , Yoshikai Y 
Published: December 2022

Abstract
Because there are limited numbers of V gamma gene segments and most V gamma rearrangements occur within clusters of the J gamma-C gamma genes in mice, gamma-chains display limited diversity compared with other TCR chains. In this study, we examined the nucleotide sequences of the V gamma-J gamma genes expressed in the gamma delta T cells appearing at the inflamed sites after Salmonella infection in DBA/2 mice. Most of the productive gamma gene rearrangements were V gamma 1-J gamma 4, whereas V gamma 2 and a unique V gamma, the 5' region of which was identical with sequences of the V gamma 2 gene, and the 3' region of which was identical with that of the V gamma 1 gene, were found to be rearranged to J gamma 4 gene, albeit at low frequency. Analysis of the ontogenic appearance of the rearrangements in the J gamma 4-C gamma 4 locus revealed that V gamma 2-J gamma 4 gene rearrangement was frequent in fetal thymocytes at the early stage of gestation. Most of the early fetal V gamma 2-J gamma 4 rearrangements exhibited the identical junction, a nonfunctional canonical sequence. The sequence analysis of the coding joint and the reciprocal recombination signal joint suggests that short homology-mediated direct recombination and chromosomal inversion mechanism are involved in fetal V gamma 2-J gamma 4 gene rearrangement. Taken together, our data suggest that the recombination of multiple V gamma segments with J gamma 4 can diversify the V gamma repertoire.
Melanoma patients immunized with melanoma cell vaccine induce antibody responses to recombinant MAGE-1 antigen.
Authors: Hoon D S , Yuzuki D , Hayashida M , Morton D L 
Published: December 2022

Abstract
The MAGE-1 gene was recently characterized to encode an immunogenic tumor Ag on several types of human tumors, including melanoma. This Ag is expressed in a wide variety of human tumors and not in normal cells, except testicular tissue, as assessed through specific mRNA analysis. In this study we cloned the MAGE-1 gene exon 3 region from a colon carcinoma cell line and expressed it in Escherichia coli. The recombinant MAGE-1 protein was affinity purified. By using Western blot analysis, IgG and IgM anti-MAGE-1 Abs were detected in the sera of melanoma patients. Fifty-three patients immunized with a melanoma cell vaccine (MCV) were assessed for anti-MAGE-1 IgG responses by using a MAGE-1 Ag-specific ELISA. The MCV consisted of three melanoma cell lines that expressed MAGE-1. Comparisons of anti-MAGE-1 IgG response pre-MCV treatment with 12- to 16-wk post-MCV treatment were made. Fifty-seven percent of the patients immunized with the MCV showed significant enhancement of IgG response to recombinant MAGE-1 protein. Patients who responded had no particular HLA-A or -B allele expression pattern. Melanoma patients immunized with whole cell MCV containing MAGE-1 can enhance anti-MAGE-1 IgG Abs. Recombinant MAGE-1 protein can be used to assess patient response to MAGE-1 and will be investigated as a potential cancer vaccine against a wide variety of human tumors that express MAGE-1.
Mechanisms underlying acute mast cell-induced leukocyte rolling and adhesion in vivo.
Authors: Gaboury J P , Johnston B , Niu X F , Kubes P 
Published: December 2022

Abstract
It has been proposed that a primary detector mechanism for tissue infection or injury may be the mast cell that releases agents that recruit leukocytes to the appropriate site at risk. The objective of this study was to evaluate the early mechanisms involved in mast cell-induced leukocyte recruitment. We used intravital microscopy to visualize leukocyte-rolling flux and adhesion in single 25 to 40 microns venules in mesenteric preparations that were treated with the mast cell-degranulating agent, compound 48/80 (CMP 48/80). Superfusion of the rat mesentery with CMP 48/80 caused a dose-dependent rise in the number of rolling and adherent cells, events significantly reduced by: 1) mast cell stabilizers, ketotifen, or cromolyn, and 2) chronic treatment with CMP 48/80 to deplete mast cell constituents. The increase in leukocyte flux associated with CMP 48/80 was blocked by diphenhydramine (H1-receptor antagonist) and an anti-P-selectin Ab (PB1.3), but not by the 5-lipoxygenase inhibitor, MK 886. The reduction in the flux of rolling leukocytes translated into fewer adherent leukocytes with diphenhydramine or PB1.3. The CMP 48/80-induced rise in leukocyte adhesion, but not leukocyte flux, was reduced by the platelet-activating factor (PAF)-receptor antagonist (WEB 2086) and an anti-CD18 Ab (CL26). MK 886 did not prevent the increased leukocyte adhesion. In vitro data revealed that mast cell-derived PAF induced essentially all of the leukocyte adhesion to endothelium or protein-coated plastic. These data suggest that mast cell degranulation induces P-selectin-dependent leukocyte rolling and CD18-dependent leukocyte adhesion via histamine and PAF, respectively.
Antitumoral properties of aged human monocytes.
Authors: McLachlan J A , Serkin C D , Morrey K M , Bakouche O 
Published: December 2022

Abstract
It is known that older people are more sensitive to cancer and infectious agents and need more time to recover from such disorders. Can this difference in sensitivity to cancer and infections between elderly and younger people be a result of a difference in their immune systems and, more specifically, in the way monocytes react to infectious agents and cancer cells? To determine what happens after cells have aged, human monocytes were purified from young donors (approximately 25 years of age) and from older donors (65 years of age or older) and tested for their ability to respond to the polyclonal activator LPS. Our results showed that monocytes from aged donors (aged monocytes), when compared with monocytes from younger donors (young monocytes) did lose part of their cytotoxicity against tumor cells (A375 human melanoma cells and L929 murine fibroblast cells). In addition, aged monocytes displayed a sharp decrease in IL-1 secretion, but did display the intracellular 31 kDa IL-1 precursor. Moreover, aged monocytes displayed a decrease in the production of reactive oxygen intermediates such as NO2 and H2O2. Finally, aged monocytes stimulated by LPS displayed an increase in intracellular cyclic AMP and have lost their protein kinase C translocation from the cytosol to the plasma membranes. These results suggest that age affects the immunologic and antitumoral properties of human monocytes.
Balance between IL-1 beta, TNF-alpha, and their specific inhibitors in chronic renal failure and maintenance dialysis. Relationships with activation markers of T cells, B cells, and monocytes.
Authors: Descamps-Latscha B , Herbelin A , Nguyen A T , Roux-Lombard P , Zingraff J , Moynot A , Verger C , Dahmane D , de Groote D , Jungers P 
Published: December 2022

Abstract
Patients with end-stage renal disease present an immunodeficiency that paradoxically coexists with activation of most immunocompetent cells, and the roles of chronic uremia and maintenance dialysis are poorly understood. We determined circulating levels of IL-1 beta and IL-1Ra, TNF-alpha and its soluble receptors (TNF-sR55 and TNF-sR75), and activation markers of T cells (soluble CD25), B cells (soluble CD23), and monocytes (neopterin) in a large cohort of undialyzed patients at various stages of chronic renal failure and in dialyzed patients on maintenance hemodialysis or chronic peritoneal dialysis. The progression of uremia was associated with a gradual increase in soluble CD25, CD23, and especially neopterin levels. Although IL-1 beta could not be detected, IL-1Ra levels were significantly increased from the earliest stage of renal failure. Plasma levels of TNF-alpha, TNF-sR55, and TNF-sR75 progressed with the severity of renal failure and correlated with soluble CD25, CD23, and neopterin levels, whereas IL-1Ra levels correlated exclusively with TNF-sR55 levels. Compared with undialyzed patients, levels of IL-1 beta were higher in patients on maintenance hemodialysis, whereas those of IL-1Ra were lower and decreased further at the end of dialysis sessions. In contrast, both TNF-sR55 and TNF-sR75 levels were significantly higher than in undialyzed patients and increased further at the end of dialysis sessions in the absence of an increase of TNF-alpha. Such an imbalance between cytokines and their inhibitors may play a pivotal role in the multifaceted process of immune dysfunction.
TNF-alpha expression by resident microglia and infiltrating leukocytes in the central nervous system of mice with experimental allergic encephalomyelitis. Regulation by Th1 cytokines.
Authors: Renno T , Krakowski M , Piccirillo C , Lin J Y , Owens T 
Published: December 2022

Abstract
The inflammatory cytokines IFN-gamma and TNF-alpha have been demonstrated in various autoimmune diseases, and are thought to participate in the induction and pathogenesis of disease. TFN-alpha is a cytopathic cytokine that is cytotoxic for oligodendrocytes in vitro and has been implicated in the pathology of multiple sclerosis and its animal model experimental allergic encephalomyelitis (EAE). We used reverse transcriptase (RT)-PCR to study the kinetics, cellular source, and regulation of cytokine gene expression in the central nervous system (CNS) of SJL/J mice with myelin basic protein-induced EAE at different stages of the disease. The expression of CD3, IL-2, IFN-gamma, and TNF-alpha mRNA was barely detectable in the CNS of unmanipulated mice or mice that were immunized with adjuvant but showed no symptoms. These mRNAs were readily detectable in the CNS of mice during peak disease, then coordinately dropped to background levels during remission. Analysis of cells isolated from the CNS of mice with acute EAE showed that the Th1 cytokines, IL-2 and IFN-gamma, were produced by infiltrating CD4+ T cells. In contrast, TNF-alpha was predominantly transcribed by non-T mononuclear CNS cells, the majority of which were identified as microglia and macrophages by their Mac-1 phenotype. Microglia could be discriminated by their low expression of CD45. Incubation of freshly derived, adult microglia from normal, uninfiltrated, CNS with activated Th1 supernatant induced the production of TNF-alpha mRNA. Therefore, TNF-alpha is made by both CNS-resident microglia and infiltrating macrophages during EAE, and this production is tightly controlled by cytokines secreted by infiltrating CD4+ T cells.