bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syrian and Armenian hamsters differ in serum amyloid A gene expression. Identification of novel Syrian hamster serum amyloid A subtypes.
Authors: de Beer M C , de Beer F C , Beach C M , Gonnerman W A , Carreras I , Sipe J D 
Published: December 2022

Abstract
Amyloid A (AA) amyloidosis is widespread throughout the animal kingdom. Several factors including: 1) precursor production; 2) precursor structure; 3) precursor degradation; and 4) precursor/product interaction with the pentraxin serum amyloid P have been implicated in amyloidogenesis, but the exact sequence of events leading to AA fibril formation and deposition remains unclear. Most models of experimental amyloidosis, including golden Syrian hamsters (Mesocricetus auratus), involve massive and repeated inflammatory stimulation; however, the model of spontaneous amyloidosis with aging in female, but not male, Syrian hamsters permits analysis of amyloidogenic factors in the absence of inflammation. Another genus, the Armenian hamster (Cricetulus migratorius), differs from Syrian hamsters both in gender-specific serum amyloid P expression and susceptibility to AA amyloidosis. In this study, we describe novel SAA molecules in the Syrian hamster in the presence and absence of inflammation. We demonstrate that, based on isoelectric separation, the Syrian hamster SAA proteins can be separated into two broad subfamilies. Plasma SAA concentration in female Syrian hamsters increases spontaneously with age, and fragments of a basic SAA isotype expressed both hepatically and extrahepatically are selectively deposited as AA fibrils. After inflammatory stimulation, the patterns of SAA gene expression in Syrian and Armenian hamsters differ. In Syrian hamsters, both hepatic SAA mRNA and the high density lipoprotein apoSAA content increase approximately 1000-fold; in Armenian hamsters, hepatic SAA mRNA is limited in quantity and different in structure; and although plasma SAA proteins increase three- to fivefold, apoSAA is not detectable in high density lipoprotein. The results suggest that regulation and site of precursor production as well as precursor structure influence AA amyloidogenesis in these two hamster genera.
Transcriptional activation of the macrophage colony-stimulating factor gene by IL-2 is associated with secretion of bioactive macrophage colony-stimulating factor protein by monocytes and involves activation of the transcription factor NF-kappa B.
Authors: Brach M A , Arnold C , Kiehntopf M , Gruss H J , Herrmann F 
Published: December 2022

Abstract
Human peripheral blood monocytes (Mo) constitutively display the beta-chain of the receptor for IL-2, whereas expression of the IL-2R alpha-chain is not constitutive but inducible with IL-2. Here we report that binding of human IL-2 to its binding site leads to transcriptional activation of the macrophage CSF (M-CSF) gene in Mo resulting in accumulation of M-CSF mRNA and subsequent release of bioactive M-CSF protein as demonstrated by ELISA and inhibition of IL-2 induced release of an activity-stimulating growth of monocyte-type colonies by a neutralizing anti-M-CSF antibody. Transcriptional activation of the M-CSF gene by IL-2 is preceded by enhanced binding activity of the transcription factor NF-kappa B to its recognition sequence in the 5' regulatory enhancer region of the M-CSF gene. Moreover, using a heterologous promoter (herpes thymidine kinase) construct containing the NF-kappa B consensus sequence, it is shown that NF-kappa B binding by an IL-2-induced monocyte-derived nuclear protein confers reporter gene (human growth hormone) activity. Taken together, our findings indicate that IL-2 induces gene expression of M-CSF in human blood-derived Mo and provide evidence for involvement of NF-kappa B in transcriptional regulation of this gene.
Th2 cells mediate IL-4-dependent local tissue inflammation.
Authors: Müller K M , Jaunin F , Masouyé I , Saurat J H , Hauser C 
Published: December 2022

Abstract
We investigated whether polyclonal murine Th1 and Th2 cells obtained after short term culture in vitro were capable of mediating tissue inflammation in vivo. Th cells were pulsed with mAb to the TCR/CD3 complex and injected into the footpads or ears of naive syngeneic recipient mice. Th1 induced delayed swelling that peaked at 24 to 48 h and lasted &gt; or = 5 days. Th2-induced swelling peaked at 6 h and lasted &lt; or = 48 h. Similar responses were also observed in athymic nude mice. Lesions with both Th1 and Th2 cells contained a predominant neutrophilic infiltrate at 6 h, and mainly mononuclear cells at 48 h. The inflammatory response with Th2 was blocked by cyclosporin A, by mAb to IL-4 or by soluble rIL-4R. The requirement for IL-4 was early and transient. Four alloreactive short term Th2 clones induced swelling in allogeneic recipients. mAb- and IL-4-dependent swelling responses were also observed with two long term Th2 clones. Our results demonstrate that Th2 cells mediate IL-4-dependent tissue inflammation, and strengthen the concept that Th2 cells play an important role in some T cell-dependent immune reactions and, possibly, in allergic disorders such as atopic dermatitis and allergic asthma.
Characterization of antigen-presenting cells that present exogenous antigens in association with class I MHC molecules.
Authors: Rock K L , Rothstein L , Gamble S , Fleischacker C 
Published: December 2022

Abstract
Exogenous Ag in the extracellular fluids do not gain access to the class I Ag-presenting pathway in most cells. However, there is an APC resident in spleen that can process and present exogenous Ag in association with class I molecules. We characterize the phenotype of this cell. This APC is of low buoyant density, is adherent to Sepharose and glass, and expresses both class II molecules and FcR. This phenotype identifies this APC as a macrophage. Resident, peptone- and thioglycolate-induced peritoneal macrophages also display this Ag-presenting activity. Analysis with CTL clones suggest that this Ag-presenting pathway may be active in only a subset of macrophages. A similar Ag-presenting activity is also present in dendritic cell-enriched populations from spleen although we cannot rule out the possible involvement of contaminating macrophages. In contrast, B and T cells that are resident in spleen and LPS blasts are unable to present exogenous Ag in association with class I molecules. The presentation of exogenous OVA with class I molecules is not inhibited by the inhibitors of thiol proteases, leupeptin, and antipain. The presence of gelonin, a ribosomal inactivating protein, in the extracellular fluids inhibits the ability of these APC to present exogenous OVA. Under identical conditions, gelonin does not inhibit Con A-stimulated T cell proliferation, or LPS-stimulated B cell proliferation and Ag presentation. These results are discussed in relation to the potential pathways through which an Ag in the extracellular fluids is presented with MHC class I molecules.
Regulation of IFN-gamma expression in vivo. IFN-gamma up-regulates expression of its mRNA in normal and lipopolysaccharide-stimulated mice.
Authors: Cockfield S M , Ramassar V , Noujaim J , van der Meide P H , Halloran P F 
Published: December 2022

Abstract
Immune responses to such stimuli as tissue injury, infection, and allografting result in localized IFN-gamma expression. Autoregulation of cytokine expression has been described for some cytokines in vitro, but whether this occurs in vivo is unknown. We therefore examined the role of murine IFN-gamma in the regulation of its own expression in vivo after stimulation with bacterial LPS. This agent is known to induce IFN-gamma expression in both spleen and kidney in a T cell-independent, cyclosporine-sensitive manner. We found that concomitant administration of a neutralizing mAb to IFN-gamma inhibited not only the MHC expression induced by LPS but also the increased IFN-gamma mRNA expression, suggesting an autoregulatory role for IFN-gamma. Inhibition was dose dependent and observed in both spleen and kidney. The effect was not seen with a neutralizing anti-IL-3 mAb, demonstrating specificity. The inhibition of IFN-gamma mRNA expression by the anti-IFN-gamma mAb occurred in both T cell-deficient athymic nude mice and their normal controls, suggesting that the autoamplification of IFN-gamma mRNA in vivo is T cell independent. Administration of rIFN-gamma to unstimulated mice induced IFN-gamma mRNA expression in spleen and kidney, supporting the conclusion that IFN-gamma up-regulates expression of its mRNA. Exposure of resting murine splenocytes to concentrations of rIFN-gamma as low as 10 U/ml in vitro induced expression of IFN-gamma mRNA. Thus, in vivo IFN-gamma may participate in an autoregulatory loop to amplify the amount of IFN-gamma expressed both at the site of local inflammation and at remote sites. This would have relevance in the mechanism by which the host defends itself against and prevents dissemination of an infectious agent.
Neutrophil priming by lipopolysaccharide involves heterogeneity in calcium-mediated signal transduction. Studies using fluo-3 and flow cytometry.
Authors: Yee J , Christou N V 
Published: December 2022

Abstract
Bacterial LPS is known to prime neutrophils for enhanced responses to subsequent stimulation by agonists such as FMLP. The purpose of this study was to determine whether priming is due to a uniform enhancement of function in all cells or to a recruitment of previously unresponsive neutrophils. Results from initial experiments confirmed the findings of other investigators and served to validate our methodology. We demonstrated that LPS-primed neutrophils had: 1) augmented superoxide anion production after FMLP or PMA stimulation; 2) increased FMLP-induced f-actin formation; 3) enhanced surface expression of CD11b, CD14, and the FMLP receptor; 4) caused higher baseline concentrations of intracellular calcium ([Ca2+]i); 5) caused greater elevations of [Ca2+]i after FMLP stimulation; and that 6) the priming effect of LPS on superoxide anion production and f-actin polymerization could be blocked by the [Ca2+]i chelator bis-(o-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid. In subsequent experiments, we determined that at low concentrations of FMLP, LPS augmented the overall responsiveness of a population of neutrophils by causing a subpopulation of cells to become highly responsive and able to generate changes in [Ca2+]i upon low level stimulation. Heterogeneity in calcium-mediated signal transduction among neutrophils may be important in the fine control of the nonspecific immune system in response to weak environmental signals.
T cell retargeting using bispecific monoclonal antibodies in a rat colon carcinoma model. II. Syngeneic colon carcinoma CC531 is efficiently killed by retargeted cytotoxic T lymphocytes in vitro despite limited lysis in 51Cr release assays.
Authors: Beun G D , Gorter A , Nooyen Y , van de Velde C J , Fleuren G J 
Published: December 2022

Abstract
We have previously described the generation of bispecific anti-TCR*anti-tumor mAb, intended for in vivo analysis of T cell retargeting in a syngeneic rat colon carcinoma model. Colon carcinoma CC531 proved to be markedly resistant to lysis by polyclonally activated, retargeted rat T lymphocytes, if measured in short term or overnight prolonged 51Cr release assays. Using cocultivation, we have now focused on another, biologically more relevant aspect of retargeted interaction: the effect on the capacity of CC531 tumor cells to survive and grow. Tumor neutralization was scored after 3 days of coculture, using a tetrazolium salt to quantify viable adherent tumor cells. Compared to 51Cr release assays, we found cocultivation to be more sensitive and more informative, as it revealed tumor cell killing at low E:T ratios, synergism of bispecific antibodies and exogenous IL-2, and free bispecific antibody-dependent recycling of effector cells. Apart from providing valuable information for future in vivo studies in this model, these data support the notion of tumor neutralization as a useful alternative for 51Cr release assays.
Autoimmunity to cytoskeletal protein tropomyosin. A clue to the pathogenetic mechanism for ulcerative colitis.
Authors: Das K M , Dasgupta A , Mandal A , Geng X 
Published: December 2022

Abstract
Autoimmunity has been emphasized in the pathogenesis of ulcerative colitis and various anticolon antibodies have been described. Nevertheless, the nature of the autoantigens has been elusive. Using ulcerative colitis colon-eluted IgG antibody, we earlier detected an M(r) 40,000 protein, P40, in colon extract. In our study, we purified P40 from human colon to apparent homogeneity, sequenced two peptides after proteolytic digestion, and demonstrated that the P40 belongs to the tropomyosin family. Furthermore, we demonstrated that blood serum from 95% of patients with ulcerative colitis contains antibodies that are reactive to tropomyosin.
Differential binding of a minor histocompatibility antigen peptide to H-2 class I molecules correlates with immune responsiveness.
Authors: Wettstein P J , van Bleek G M , Nathenson S G 
Published: December 2022

Abstract
Minor histocompatibility (H) Ag are recognized in the context of MHC class I (K/D) molecules and can constitute a strong barrier to tissue transplantation. The products encoded by the MHC (H-2 in mice) have been shown recently to be Ag-presenting molecules that bind foreign and self peptides in their peptide binding sites. Different class I molecules preferentially bind different arrays of endogenous peptides for presentation to CTL. Previous studies showed that the Kb-restricted CTL response to one minor histocompatibility Ag, H-4, varied in different Kb mutants. One possible basis for this variation might be that the response is regulated by the level of binding of an H-4 peptide by class I molecules. To analyze this possibility, we initiated studies to identify the H-4 peptide that is included in the array of self peptides. The complete mixture of peptides eluted from Kb molecules of H-4+ tumor cells was able to sensitize H-4- targets for lysis by H-4-specific CTL. The presence of a specific H-4 peptide was confirmed when the radiolabeled peptide mix eluted from Kb molecules was separated by HPLC. Only one peak in the profile of H-4+ tumor peptides was capable of sensitizing H-4- targets for lysis by H-4-specific CTL; this active peak was absent in H-4 mutant cells. Peptide mixtures eluted from a panel of Kb mutant molecules extracted from H-4+ lymphocytes varied in their capacities to sensitize targets for H-4-specific lysis and the relative sensitization correlated with the demonstrated capacity of mutant mice to generate H-4-specific CTL. Therefore, the highly specific genetic control of the T cell response to the H-4 minor histocompatibility Ag appears to be due to the differential binding of an H-4 peptide by class I molecules.
Differential nuclear expression of enhancer A DNA-binding proteins in human first trimester trophoblast cells.
Authors: Boucraut J , Hawley S , Robertson K , Bernard D , Loke Y W , Le Bouteiller P 
Published: December 2022

Abstract
In order to investigate the possible molecular regulatory mechanisms that repress classical HLA class I and stimulate nonclassical HLA-G and E-class I gene transcription in human trophoblast cells, we searched for the nuclear expression of the enhancer A DNA-binding proteins of the KBF1/NF-KB/rel family. Using both purified extravillous cytotrophoblast and villous syncytiotrophoblast from first trimester human placenta, it appeared that members of this family were present in the cytotrophoblast and absent in the syncytiotrophoblast. First, using the double stranded enhancer A DNA nucleotidic sequence that contains the palindromic KB site, known to be the binding site of the p50 subunits of KBF1-NF-KB and c-rel factors, we demonstrated, by band-shift assay, that binding activity, inhibited by addition of anti-p50 polyclonal serum, was present in cytotrophoblast as well as control maternal decidual cells, embryonic fibroblasts, and the trophoblast-derived JAR cell line. In contrast, this DNA-protein complex was undetectable in syncytiotrophoblast nuclear extracts. The specificity of this protein-DNA complex was further demonstrated by its disappearance upon competition with an excess of cold homologous nucleotidic competitor. Other nucleoprotein complexes were also detected in all nuclear extracts, including syncytiotrophoblast, that were competed out by an excess of cold enhancer A competitor DNA but were not affected by the addition of anti-p50 or anti-NF-KB sera, suggesting the presence of additional enhancer A-binding factors different from the KBF1/NF-KB/rel family. Second, using a Western immunoblot analysis, a doublet around 85 kDa was specifically stained by the same anti-p50 serum in cytotrophoblast, maternal decidual cells, embryonic fibroblasts, and the JAR nuclear extracts whereas no signal was obtained in syncytiotrophoblast. Finally, immunofluorescence cell staining using the same anti-p50 serum showed a positive staining in both cytoplasm and nucleus of cytotrophoblast and its absence in syncytiotrophoblast. We hypothesize that this enhancer A DNA-binding factor might represent the c-rel trans-acting factor, related to p50/KBF1/NF-KB proteins, and we discuss its possible relevance to the HLA class I transcription in human tissues.
Major role of antigen-presenting cells in the response of rat encephalitogenic T cells to myelin basic proteins.
Authors: Sun D , Le J , Yang S , Malotkey M , Coleclough C 
Published: December 2022

Abstract
The encephalitogenic potential of a segment of myelin basic protein in experimental autoimmune encephalomyelitis is not always mirrored by the ability of the peptide to mediate in vitro activation of encephalitogenic T cells. Recent studies from our laboratory have demonstrated that the responsiveness of Ag-specific T cells in experimental autoimmune encephalomyelitis is determined not exclusively by Ag but also by the nature of the APC. By varying APC during the in vitro selection of T cells, we could generate distinct sets of rat encephalitogenic T cells, as evidenced by the diversity of TCR usage. Here we establish the importance of APC in the activation of rat encephalitogenic T cells by myelin basic protein peptides. Peptides 69-84-Gly and (P80)68-86, which lacked stimulatory activity toward many encephalitogenic T cells in our proliferation assay when standard APC were used, become strongly stimulatory in the presence of less commonly used APC, i.e., an Ia+ T cell clone (LOA) or an Ia-inducible rat glial cell clone (F10). Nonstimulatory APC failed to activate encephalitogenic T cells even when major cytokines were added, suggesting that these cytokines are not among the factors limiting the activating potential of the APC. Thus, whether or not an immunocompetent T cell can be activated by a given Ag in an autoimmune response may be determined by the properties of APC. This finding has implications for current research efforts to identify pathogenic self proteins.
Recognition of human insulin in the context of HLA-DRB1*0406 products by T cells of insulin autoimmune syndrome patients and healthy donors.
Authors: Ito Y , Nieda M , Uchigata Y , Nishimura M , Tokunaga K , Kuwata S , Obata F , Tadokoro K , Hirata Y , Omori Y 
Published: December 2022

Abstract
Our recent study indicated that all the insulin autoimmune syndrome (IAS) patients had specific HLA class II alleles, the DRB1*0406, DQA1*0301, and DQB1*0302, which allowed T cells to proliferate when autologous APC were exposed to human insulin. The study implied that gene products of DRB1*0406, DQA1*0301, and/or DQB1*0302 may be involved in the presentation of human insulin to T cells. We therefore examined T cell response of healthy donors with different HLA phenotypes to human insulin using an autologous MLR system. The T cells from not only IAS patients but also healthy donors were able to proliferate after exposure of human insulin to autologous APC with DRB1*0406, DQA1*0301, and DQB1*0302 products. The class II molecules are considered to be involved in the recognition of human insulin by T cells. The proliferative response of T cells was completely blocked by anti-HLA-DR mAb and not by anti-HLA-DQ mAb or other mAb. Furthermore, human insulin-specific CD4-positive T cell clones were established from blast cells in autologous MLR of PBMC from two healthy donors with DRB1*0406 in the presence of human insulin. Using DRB1*0406-transfected L cells as APC, we confirmed that these T cells clones recognize human insulin in the context of gene products of DRB1*0406. These results provide the first evidence that HLA-DRB1*0406 products act as the dominant restriction element for the presentation of human insulin to T cells, and suggest that this particular class II gene, HLA-DRB1*0406, contributes to the development of IAS.
Antibody specificities of Thai and Australian scleroderma sera with topoisomerase I recombinant fusion proteins.
Authors: Cram D S , Fisicaro N , McNeilage L J , Coppel R L , Harrison L C 
Published: December 2022

Abstract
Autoantibodies that react with the nuclear enzyme topoisomerase I (Topo I) are used as a diagnostic marker of diffuse scleroderma. To better define immune reactivity to Topo I, antibody epitopes in two patient populations were analyzed using recombinant Topo I proteins. Two overlapping partial cDNA clones encoding the complete amino acid sequence of Topo I were isolated from human placenta. Using the polymerase chain reaction, specific regions of Topo I were amplified and cloned into the pGEX expression vectors. To map Topo I epitopes, recombinant fusion proteins were analyzed by immunoblotting with 66 anti-Topo I sera from Thai and Australian patients with diffuse scleroderma. Six distinct epitope regions were identified along the length of the 765 amino acid enzyme. Almost all sera contained antibodies that recognized the midregion of Topo I (amino acids 453-560), as well as antibodies to one of more of the other epitope regions. Sixty percent of the sera contained antibodies that recognized a COOH-terminal epitope region (amino acids 658-765) encompassing the active site of the enzyme. This subset of Topo I antibodies could be responsible for the inhibition of enzymatic activity previously reported in vitro. Heterogeneous patterns of reactivity with the six Topo I epitope regions were observed, although over half the sera could be assigned to one of six distinct patterns. In general, antibodies in the Thai sera reacted more strongly with the six epitope regions. Furthermore, two of the epitope regions reacted exclusively with Thai sera, suggesting a degree of racial or geographical specificity in the autoantibody response to Topo I. The identification of multiple epitopes in Topo I conforms with the polyclonal autoantibody response to intracellular Ag found in other multisystem autoimmune diseases and is presumed to be driven by the presentation of multiple peptides from Topo I itself.