bluuebunny/crossref_metadata_2025_split huggingface dataset:
A p55 TNF Receptor Immunoadhesin Prevents T Cell-Mediated Intestinal Injury by Inhibiting Matrix Metalloproteinase Production
Authors: Pender Sylvia L. F. , Fell John M. E. , Chamow Steven M. , Ashkenazi Avi , MacDonald Thomas T. 
Published: January 2023

AbstractAnti-TNF-α Ab therapy has been shown to be of benefit in the treatment of active Crohn’s disease, but the tissue-injuring processes in the gut mediated by TNF-α that might be inhibited by neutralizing Ab are unknown. In this work, we have used a p55 TNF receptor-human IgG fusion protein (TNFR-IgG) to prevent the severe mucosal injury that ensues when lamina propria T cells in explant cultures of human fetal small intestine are directly activated with the lectin PWM. Following T cell activation and associated with mucosal injury, there is a marked elevation of soluble TNF-α in organ culture supernatants and a large increase in TNF-α mRNA transcripts. The addition of TNFR-IgG at the onset of cultures greatly reduced PWM-induced tissue injury, without inhibiting the increase in TNF-α and IFN-γ transcripts seen following T cell activation. Mucosal injury in this model is mediated by endogenously-produced matrix metalloproteinases (MMPs). When TNFR-IgG was added to PWM-stimulated explants, there was a reduction in MMPs in the explant culture supernatants, especially stromelysin-1. Recombinant TNF-α and IL-1β added directly to mucosal mesenchymal cell lines also caused an increase in MMP production, but only the former was inhibited by the TNFR-IgG. These results suggest that one of the ways in which TNF-α causes tissue injury in the gut is by stimulating mucosal mesenchymal cell to secrete matrix-degrading metalloproteinases. Neutralization of this activity should help maintain tissue integrity.
Complement-Fixing Elicited Antibodies Are a Major Component in the Pathogenesis of Xenograft Rejection
Authors: Miyatake Tsukasa , Sato Koichiro , Takigami Ko , Koyamada Nozomi , Hancock Wayne W. , Bazin Herve , Latinne Dominique , Bach Fritz H. , Soares Miguel P. 
Published: January 2023

Abstract
Hamster to rat cardiac xenografts undergo delayed rejection as compared with the hyperacute rejection of discordant xenografts. Elicited xenoreactive Abs (EXA) are thought to initiate hamster to rat cardiac xenograft rejection. In this study, we demonstrate that following transplantation of a hamster heart, rats generated high levels of EXA. Adoptive transfer into naive recipients of purified IgM, IgG2b, or IgG2c, but not IgG1 or IgG2a EXA, induced xenograft rejection in a complement-dependent manner. Ability of EXA to cause rejection correlated with complement activation, platelet aggregation, and P-selectin expression in the xenograft endothelium. Cyclosporin A (CyA) administration, after transplantation, totally suppressed IgG1, IgG2a, IgG2b, and IgG2c EXA, and inhibited IgM EXA production, but failed to overcome rejection. Administration of cobra venom factor (CVF), 1 day before and at the time of transplantation, resulted in complement inhibition during 3 days after transplantation, which failed to overcome rejection. Combination of CyA and CVF, which we have previously shown to overcome rejection, resulted in suppression of IgG EXA production and in the return of IgM XNA to preimmunization serum levels, 3 to 7 days after xenotransplantation, while complement remained inhibited. Thus, under CyA/CVF treatment, complement activation by hamster cells was suppressed following xenotransplantation, and presumably for this reason xenograft rejection did not occur. In conclusion, our data demonstrate that EXA play a pivotal role in the pathogenesis of xenograft rejection and that CyA and CVF suppress xenograft rejection by preventing exposure of xenograft endothelial cells to complement activation by EXA.
Technical Note: Aberrant Detection of Cell Surface Fas Ligand with Anti-Peptide Antibodies
Authors: Smith Dawn , Sieg Scott , Kaplan David 
Published: January 2023

AbstractPolyclonal rabbit Abs raised against peptides from the C-terminal region (the extracellular domain) of human Fas ligand were produced for the detection of the molecule in Western blot analysis and immunohistochemistry. These Abs have been used by several groups of investigators to assess cell surface Fas ligand via flow cytometry, but we show that these polyclonal rabbit Abs do not detect cell surface Fas ligand by that technique.
Hybrid Membrane IgM with the Transmembrane Region of I-Aα Facilitates Enhanced Presentation of Distinct Epitopes to T Cells
Authors: Liu Ko-Jiunn , Schwen Michael , Tucker Philip W. , Kim Byung S. 
Published: January 2023

AbstractThe role of B cell Ag receptors (membrane Ig or mIg) in the efficient Ag presentation to T cells, including the requirement of mIgM-associated Igα/Igβ, remains unclear. We report here that mIgM, substituted with greater than two-thirds of the NH2-terminal Aα transmembrane (TM) regions of the MHC class II molecule, are capable of mediating the efficient presentation of specific Ag to some (Group 1) but not all (Group 2) T cell hybridomas. In contrast, the generation of epitopes recognized by the Group 2 hybridomas can be mediated only by the wild-type mIgM. Tyrosine phosphorylation appears to be necessary for the enhanced Ag presentation to Group 2 hybridomas, while it does not for Group 1 hybridomas. In addition, differential sensitivity of Ag processing to leupeptin, different duration required for epitope generation/presentation, as well as the involvement of distinct epitopes for stimulation of these groups of T cell hybridomas were observed. These results suggest that transport of the mIgM/Ag complexes to an endocytic compartment(s) for generation of certain T cell epitopes may be mediated by the N-terminal TM sequence of mIgM, independent of Igα/Igβ association. This function can be replaced by two-thirds of the NH2-terminal TM region of Aα chain of class II molecules.
Polymorphism at the HLA-DQ Locus Determines Susceptibility to Experimental Autoimmune Myasthenia Gravis
Authors: Raju Raghavan , Zhan Wen-Zhi , Karachunski Peter , Conti-Fine Bianca , Sieck Gary C. , David Chella 
Published: January 2023

AbstractStudies in myasthenia gravis (MG) patients demonstrate that polymorphism at the HLA-DQ locus influences the development of MG. Several studies using the mouse models also demonstrate the influence of class II molecules, especially the H2-A, which is the mouse homologue of HLA-DQ, in experimental autoimmune myasthenia gravis (EAMG). We used transgenic mice expressing two different DQ molecules, DQ8 (DQA1*0301/B1*0302) and DQ6 (DQA1*0103/B1*0601), to evaluate the role of HLA-DQ genes in MG. These mice do not express endogenous mouse class II molecules since they contain the mutant H2-Aβ0 gene. The mice were immunized with Torpedo acetylcholine receptor, and EAMG was assessed by clinical evaluation and was confirmed by electrophysiology. Clinical scores for EAMG were highest in HLA-DQ8 transgenic mice, whereas the scores of HLA-DQ6 mice rarely exceeded grade 1. There was no incidence of EAMG in class II-deficient (H2-Aβ0) mice. These results demonstrate that polymorphism at the HLA-DQ locus affects the incidence and the severity of EAMG. The manifestation of susceptibility to EAMG in the context of human class II molecules underscores the important roles of these molecules in the initiation and perpetuation of EAMG.
Costimulation via TCR and IL-1 Receptor Reveals a Novel IL-1α-Mediated Autocrine Pathway of Th2 Cell Proliferation
Authors: Huber Magdalena , Beuscher Horst U. , Rohwer Peter , Kurrle Roland , Röllinghoff Martin , Lohoff Michael 
Published: January 2023

AbstractPrevious studies have shown that triggering of Th2 cells via the TCR is sufficient for production of IL-4 but not for proliferation of these cells. Proliferation of Th2 cells occurs only in the additional presence of a costimulatory signal delivered by IL-1. For the majority of Th2 cell clones, this type of proliferation was found to be independent of IL-4. Here, we further investigated the mechanism of IL-4-independent proliferation. We demonstrate that, after costimulation via TCR and IL-1R, but not via either receptor alone, Th2 cells are triggered to produce cell-associated IL-1α, as detected at the level of function, protein, and mRNA expression. In the presence of the TCR signal, autocrine IL-1α is then able to costimulate IL-4-independent proliferation of Th2 cells and to further enhance its own production. Thus, our results point to a novel, IL-4-independent, self-amplifying autocrine pathway of Th2 cell proliferation that requires a signal via the TCR and a costimulatory signal via IL-1R. This pathway may explain frustrating results in experimental models that attempted to treat established Th2-mediated diseases in vivo with IL-4-neutralizing agents alone.
Ultraviolet Light-Induced Immune Tolerance Is Mediated via the Fas/Fas-Ligand System
Authors: Schwarz Agatha , Grabbe Stephan , Grosse-Heitmeyer Karin , Roters Berthold , Riemann Helge , Luger Thomas A. , Trinchieri Giorgio , Schwarz Thomas 
Published: January 2023

Abstract
Hapten sensitization through UV-exposed skin induces tolerance that is mediated via the induction of hapten-specific T suppressor cells. However, the detailed mechanisms underlying tolerance induction remain unclear to date. We show here that the apoptosis-related surface Ag Fas (APO-1, CD95) and its ligand, Fas ligand (FasL) are critically involved, since Fas-deficient lpr mice and FasL-deficient gld mice do not develop UV-induced tolerance. Adoptive transfer experiments revealed that the mediation of tolerance does not require the expression of Fas or FasL by the T suppressor cells but does require the expression of both molecules by the cells of mice receiving the T suppressor cells. To identify the mechanisms involved, the effect of suppressor cells on Ag-presenting dendritic cells (DC) was studied. Coincubation of hapten-pulsed DC with T cells that were obtained from UV-tolerized mice resulted in an enhanced death rate of DC, and this cell death was dependent upon Fas expression. The addition of IL-12, which recently was found to break established tolerance in vivo, prevented DC death. Moreover, IL-12 did not only rescue DC from T suppressor cell-induced death but also from apoptosis induced by rFasL, suggesting that IL-12 may interfere with the Fas/FasL system. Together, these data indicate a crucial role for the Fas/FasL system in UV-induced tolerance, and suggest that UV-induced T suppressor cells may act by inducing the cell death of APCs via the Fas pathway. The ability of IL-12 to break established tolerance may be due to the prevention of DC death induced by T suppressor cells.
TNF-α Messenger RNA and Protein Expression in the Uteroplacental Unit of Mice with Pregnancy Loss
Authors: Gorivodsky Marat , Zemlyak Ilona , Orenstein Hasida , Savion Shoshana , Fein Amos , Torchinsky Arkady , Toder Vladimir 
Published: January 2023

AbstractAn elevated expression of TNF-α in embryonic microenvironment was found to be associated with postimplantation loss. In this work, we examined the pattern of TNF-α expression at both the mRNA and the protein level as well as the distribution of TNF-α receptor mRNA in the uteroplacental unit of mice with induced (cyclophosphamide-treated) or spontaneous (CBA/J × DBA/2J mouse combination) pregnancy loss. RNase protection analysis demonstrated an increase in TNF-α mRNA expression in the placentae of mice with pregnancy loss compared with that in control mice. TNF-α messages were localized to the uterine epithelium and stroma as well as the giant and spongiotrophoblast cells of the placenta. The intensity of the hybridization signal in placentae of mice with pregnancy loss was substantially higher than that in control mice. The up-regulation of TNF-α mRNA was accompanied by an increase in the expression of TNF-α receptor I mRNA in the same cell populations. The elevation of TNF-α production was also demonstrated at the protein level. Western blot analysis showed an increased level of the 18- and 26-kDa TNF-α protein species in the uteroplacental unit of mice with pregnancy loss. Immunostaining revealed TNF-α-positive leukocytes located in the uterus and placenta. Finally, we found that immunization of mice with cyclophosphamide-induced pregnancy loss while decreasing the resorption rate in these females resulted in a decline in TNF-α expression at the fetomaternal interface. These data clearly suggest an involvement of TNF-α in pathways leading to both spontaneous and induced placental death.
Induction of Fas Ligand in Murine Bone Marrow NK Cells by Bacterial Polysaccharides
Authors: Halaas Øyvind , Vik Randi , Espevik Terje 
Published: January 2023

AbstractBacterial polysaccharides have a wide range of activities in mammals. We have studied the effect of LPS and poly-β-(1→4)-d-mannuronate (mannuronan, poly-M), an exopolysaccharide from Pseudomonas aeruginosa, on the cytotoxicity mediated by murine bone marrow cells (BMC). Addition of LPS or mannuronan to BMC induced a time- and dose-dependent cytotoxicity against Jurkat cells. The LPS- or mannuronan-induced cytotoxicity was due to increased Fas ligand (FasL) expression by BMC, since 1) Fas-transfected L1210-Fas target cells were more susceptible to lysis than the Faslow-expressing parent L1210 cells, 2) stimulated BMC from FasL-defective gld/gld mice were not cytolytic and, 3) the cytolytic activity of normal BMC was inhibited by a Fas-Fc fusion protein. Flow cytometry showed an increase in surface FasL in LPS-stimulated BMC. RT-PCR analysis of BMC revealed constitutive expression of FasL mRNA, which was increased after LPS stimulation. Immunomagnetic depletion of NK1.1-, CD2-, or CD32/16-expressing cells from BMC abrogated the LPS-induced BMC cytotoxicity against L1210-Fas cells, suggesting that NK cells were the cytotoxic effector cells. Depletion of CD45R/B220-, Gr-1-, or CD11b/Mac-1-expressing cells only partially decreased BMC-mediated cytotoxicity, and depletion of CD4- or CD8a-expressing cells had no effect. The results support the conclusion that LPS and mannuronan induce expression of cytotoxic FasL on bone marrow NK cells.
Regulation of Transcription of the TATA-less Human Complement Component C4 Gene
Authors: Vaishnaw Akshay K. , Mitchell Tracey J. , Rose S. Jane , Walport Mark J. , Morley Bernard J. 
Published: January 2023

AbstractThe 5′-sequences flanking the human complement component C4 genes (C4A and C4B) have been analyzed for their ability to direct expression of a reporter gene in cell lines that constitutively express or do not express C4. No difference in the level of reporter gene expression was detected in cells transfected with C4A- or C4B-specific constructs. A series of reporter constructs containing progressively truncated C4 promoter fragments transfected into the hepatocyte Hep G2 cell line, identified the sequence contained within the region −178 to −39 as that associated with maximal reporter gene expression. This region contains consensus binding motifs for nuclear factor 1 (−110 to −97), Sp1 (−57 to −49), and three basic helix-loop-helix (−137 to −132, −98 to −93, and −78 to −73)-like transcription factors. Electromobility shift assays and DNase I footprinting analysis showed specific DNA-protein interactions of the C4 promoter at the nuclear factor 1, two E box (−98 to −93 and −78 to −73), and Sp1 binding domains. Site-directed mutagenesis of the Sp1 binding site resulted in total abrogation of reporter gene expression and mutation of the E box (−78 to −73) resulted in a 8-fold reduction in expression. We conclude that the Sp1 binding site at position −57 to −49 is critical for accurately initiated, basal transcription of C4.
MHC Class I/Peptide Stability: Implications for Immunodominance, In Vitro Proliferation, and Diversity of Responding CTL
Authors: Busch Dirk H. , Pamer Eric G. 
Published: January 2023

AbstractInfection of BALB/c mice with Listeria monocytogenes primes CD8+ cytotoxic T cells specific for four different H2-Kd-restricted peptides. In vitro restimulation of L. monocytogenes immune splenocytes with each of these peptides resulted in larger T cell responses to p60 217–225 and mpl 84–92 than to LLO 91–99 and p60 449–457. Direct frequency analyses of immune splenocytes, however, revealed that LLO 91–99 and p60 217–225 elicit dominant T cell responses, while p60 449–457 and mpl 84–92 elicit minor, subdominant responses. Restimulation of immune splenocytes with a range of peptide concentrations revealed that T cells with dominant specificities respond optimally to low peptide concentrations, while T cells specific for subdominant epitopes expand maximally to high peptide concentrations. This disparity correlates with the stability of H2-Kd/epitope complexes: the two dominant epitopes form stable complexes, while the subdominant epitopes form less stable complexes with H2-Kd. Interestingly, T cells specific for LLO 91–99 and p60 217–225 express more complex TCR-Vβ repertoires than p60 449–457- and mpl 84–92-specific T cells. Thus, in our system, dominant T cell responses have relatively diverse TCR repertoires and are specific for peptides that form stable complexes with MHC class I molecules. Determining the precise roles of epitope/MHC class I stability and TCR repertoire in the generation of dominant T cell responses will require further investigation.
Enhancement of Tumor Outgrowth Through CTL Tolerization After Peptide Vaccination Is Avoided by Peptide Presentation on Dendritic Cells
Authors: Toes René E. M. , van der Voort Ellen I. H. , Schoenberger Stephen P. , Drijfhout Jan Wouter , van Bloois Louis , Storm Gert , Kast W. Martin , Offringa Rienk , Melief Cornelis J. M. 
Published: January 2023

AbstractSynthetic peptide-based vaccines have been shown to induce potent protective and therapeutic T cell-mediated immunity in preclinical animal models and are now being evaluated in clinical phase I/II studies for their efficacy against tumors or infectious diseases. However, such vaccines might also specifically tolerize T cells causing enhanced tumor outgrowth, as shown by vaccination with two CTL epitopes derived from the adenovirus type 5 early region 1 (Ad5E1) oncogenes. We now report that modification of the Ad5E1 peptide vaccine either through incorporation of the peptides into liposomes or by ligation of the peptides to lipid tails, another vaccine formulation being tested in the clinic, fails to convert immunosuppression into effective antitumor vaccination. Inclusion of a helper T cell epitope into the vaccine likewise induces enhanced tumor outgrowth and thus does not diminish the capacity of the peptides to tolerize Ad5E1-specific CTL. In contrast, the Ad5E1-derived peptides evoke a strong tumor-protective CTL response when presented on dendritic cells (DC), indicating that the in vivo CTL-tolerizing potential of these peptides is converted to specific immunostimulation when presented on DC. These findings have important implications for the development of peptide-based immune intervention strategies and emphasize the superior nature of Ag-pulsed DC over other peptide-based vaccination protocols as well as the crucial importance of the mode of peptide-Ag delivery in setting the balance between T cell stimulation and tolerization.
TNF-α Convertase Enzyme from Human Arthritis-Affected Cartilage: Isolation of cDNA by Differential Display, Expression of the Active Enzyme, and Regulation of TNF-α
Authors: Patel Indravadan R. , Attur Mukundan G. , Patel Rajesh N. , Stuchin Steven A. , Abagyan Ruben A. , Abramson Steven B. , Amin Ashok R. 
Published: January 2023

AbstractA snake venom-like protease isolated by a differential display screen between normal and osteoarthritis (OA)-affected cartilage (designated as cSVP) has a cDNA sequence identical to TNF-α convertase enzyme (TACE). TACE shows the presence of an unknown prodomain, a cysteine switch, a catalytic domain, a zinc binding region, a disintegrin region, an EGF-like domain, a transmembrane domain, and a unique cytoplasmic region. A TACE construct harboring the signal + prodomain + catalytic region (TACE-SPCΔDETCy), expressed in baculovirus could cleave preferentially (∼12-fold) the TNF-specific peptide over the matrix metalloproteases peptide in vitro. This recombinant protein also cleaved the natural substrate GST-ProTNF-α to TNF-α (17 kDa) in vitro. The mRNA for TACE, which is broadly distributed and differentially expressed in a variety of human tissues, is up-regulated in arthritis-affected cartilage, but not normal cartilage. OA-affected cartilage also expressed TNF-α mRNA that was not detected in normal cartilage. The OA-affected cartilage (in explant assays) spontaneously released TNF-α and IL-8 in ex vivo conditions. Addition of TNF-αR fused to IgG Fc fragment (TNF-αR:Fc) in the presence or absence of soluble IL-1R (with which it acted additively) significantly attenuated the spontaneous/autocrine release of articular IL-8 in this assay. These experiments demonstrate a functional paracrine/autocrine role of TNF-α in OA-affected cartilage that may depend, in part, on up-regulated levels of chondrocyte-derived TACE.
Cutting Edge: TRANK, a Novel Cytokine That Activates NF-κB and c-Jun N-Terminal Kinase
Authors: Haridas Valsala , Ni Jian , Meager Anthony , Su Jeffery , Yu Guo-Liang , Zhai Yifan , Kyaw Hla , Akama Keith T. , Hu Jingru , Van Eldik Linda J. , Aggarwal Bharat B. 
Published: January 2023

AbstractWe searched the expressed sequence tag database using sequence homology and identified a novel cytokine, which we have named TRANK (thioredoxin peroxidase-related activator of NF-κB and c-Jun N-terminal kinase). The predicted amino acid sequence of TRANK was highly homologous to that of the thiol-specific antioxidant proteins. Unlike these proteins, however, TRANK had a putative secretory signal polypeptide and was found to be secreted by cells. TRANK was expressed in most tissues and cell lines, and the gene that encodes it was mapped to chromosome Xp21–22.1. TRANK activated NF-κB and induced the degradation of the inhibitory subunit of NF-κB. In addition, TRANK up-regulated the expression of NF-κB-dependent gene products, ICAM-1, and inducible nitric oxide synthase. TRANK also activated c-Jun N-terminal kinase and induced the proliferation of normal human foreskin fibroblasts. Its homology with antioxidant proteins, wide distribution in tissues, and ability to activate NF-κB and c-Jun N-terminal kinase suggest that TRANK plays an important role in inflammation.
In Vivo Expression of a TCR Antagonist: T Cells Escape Central Tolerance But Are Antagonized in the Periphery
Authors: Williams Calvin B. , Vidal Karine , Donermeyer David , Peterson Daniel A. , White J. Michael , Allen Paul M. 
Published: January 2023

AbstractTransgenic 3.L2 T cells are stimulated by Hb(64–76)/I-Ek and are positively selected on I-Ek plus self-peptides. To this pool of self-peptides we have added a single, well-defined 3.L2 TCR antagonist (A72) in vivo. We find that mice expressing both the 3.L2 TCR and A72 have a minimal loss of T cells expressing the clonotypic TCR in the thymus and spleen. Importantly, the proliferative response of 3.L2 × A72 splenocytes is significantly reduced compared with splenocytes from 3.L2 mice. This reduced response can be attributed to peripheral antagonism. Thus we have identified a new class of self-ligands whose predominant effect is constitutive peripheral antagonism rather than negative selection. The net effect of these ligands is to avoid potential self-reactivity while maintaining as large a repertoire as possible.