bluuebunny/crossref_metadata_2025_split huggingface dataset:
T cell clones from psoriasis skin lesions can promote keratinocyte proliferation in vitro via secreted products
Authors: Prinz Jörg Christoph , Groß Bernhard , Vollmer Sigrid , Trommler Paul , Strobel Isolde , Meurer Michael , Plewig Gerd 
Published: March 2007

AbstractPsoriasis vulgaris has been recognized lately as an immunologically mediated inflammatory skin disease. To analyze the pathogenetic role of T lymphocytes in the generation of psoriatic skin lesions, 105 T cell clones (TCC) and 10 T cell lines (TCL) were differentially isolated from dermis and epidermis of psoriatic skin specimens. Supernatants prepared from these T cells were studied for their effects on keratinocyte proliferation in vitro. Conditioned media from 14 of 77 epidermal TCC, 7 of which were CD8+, and from 8 of 28 dermal TCC, 5 of which were CD8+, reproducibly enhanced keratinocyte proliferation, with more pronounced mitogenic activities found in dermal TCC. Another 9 epidermal and 3 dermal TCC did not affect keratinocyte growth and supernatants from the remaining clones, as well as from the 5 epidermal and 5 dermal TCL, inhibited keratinocyte replication to varying degrees. Both mitogenic and suppressive activities were largely abolished by addition of an antiserum to interferon‐gamma (IFN‐γ), while addition of epidermal growth factor or irradiated psoriatic TCL had little effect on the activities of the supernatants.These studies reveal that a subpopulation of lesional psoriatic T lymphocytes is capable of enhancing keratinocyte proliferation in vitro via secreted products. Their mitogenic capacity most likely requires IFN‐γ, but the ultimate effect is apparently determined by the presence of additional cytokines. Activation of T cells secreting such combinations of factors in vivo may contribute to the keratinocyte alterations characteristic of psoriatic skin lesions.
C3 binds with similar efficiency to Fab and Fc regions of IgG immune aggregates
Authors: Antón Luis C. , Ruiz Sol , Barrio Elena , Marqués Guillermo , Sánchez Angel , Vivanco Fernando 
Published: March 2007

AbstractThe covalent binding reaction of the third component of complement (C3) with rabbit IgG immune aggregates has been studied by enzymic digestion of C3b‐IgG adducts. In these adducts C3b was radioactively labeled in the free thiol group generated during activation of the internal thioester of C3. Trypsin digestion of 14C‐labeled C3b‐IgG adducts degrades C3b to a small antibody‐bound 14C‐labeled C3 fragment (14C‐C3frg), whereas the antibody remains unaltered. Papain digestion of trypsin‐treated 14C‐C3frg‐IgG complexes generated Fc and Fab fragments bearing equivalent amounts of covalently bound 14C‐C3frg (43% and 40%, of the total C3 present in the aggregates, respectively). Hydroxylamine treatment of the 14C‐C3frg‐Fab and 14C‐C3frg‐Fc complexes released a 14C‐C3frg of similar size (about 3–4 kDa) in which the N‐terminal residue was the radiolabeled Cys1010. A fragment with the same radioactive N terminus and characteristics was obtained by sequential trypsin and papain digestion of purified C3 labeled with iodo–[14C] acetamide.Affinity‐purified 14C‐C3frg‐Fc complexes digested with pepsin generated a mixture of radioactive peptides, most probably complexes formed by 14C‐C3frg and Cγ2 or the hinge digestion products, and 14C‐C3frg‐pFc' complexes. The latter was also immunoprecipitated with anti‐Fc‐Sepharose from the pepsin digestion supernatants of 14C‐labeled‐C3b‐IgG complexes.Taken together these data indicate that, during complement activation through the alternative pathway by IgG immune aggregates, C3 is not bound to a single site on the antibody molecule. Both Fab and Fc regions of IgG are equally efficient targets for C3 anchorage. In addition, the data confirm the pFc' as a region of C3 attachment within the Fc portion, and strongly suggest that C3b is bound either to the Cγ2 domain or the hinge or both.
Characterization of a novel human T cell receptor β chain variable region family by transspecies DNA hybridization
Authors: Hall Margaret A. , Jaeger Emma E. M. , Bontrop Ronald E. , Lanchbury Jerry S. 
Published: March 2007

AbstractOne essential component in the generation of diversity of T cell receptor (TcR) α and β chains is the existence of multiple tandemly arranged variable regions in the germ line which are subsequently rearranged to form functional units. In attempting to establish the extent of the human TcR α and β chain repertoire an approach of randomly sequencing cDNA for rearranged receptors has been generally pursued. So far, 24 human Vβ families have been characterized and they encompass some 51 transcriptionally active gene segments. Recently, surveys of several hundred TcR β cDNA clones have failed to establish further Vβ families which suggests that if they exist, they are likely to be poorly represented in the peripheral blood repertoire. It is likely, therefore, that the majority of human Vβ regions which are rearranged conventionally and are transcriptionally active have already been described. To investigate whether additional Vβ families characterize the human TcR repertoire we have examined Vβ sequences from an inverse polymerase chain reaction (PCR) TcR β cDNA library of the chimpanzee, the most closely related creature to man. One clone which could not be assigned to any human Vβ family cross‐hybridized with human TcR β chain cDNA. This new human family has been called Vβ25. Comparison of chimpanzee and human Vβ25 sequences using the Lipman‐Pearson method gives a similarity index of 94.6% over a consensus length of 112 amino acids. On the evidence of Southern blotting with cDNA probes, Vβ25 segments in human and chimpanzee appear to represent single member gene families and no restriction fragment length polymorphism was evident with the restriction enzymes used. Equalization of TcR β cDNA followed by family‐specific quantitative PCR showed that the gene is expressed at similar levels in the chimpanzee and the human. The actual level of expression in the human is less that 0.5% of the total TcR β repertoire. Transspecies DNA hybridization using novel sequences from closely related species may be a powerful tool for establishing the full extent of TcR α and β and immunoglobulin repertoires.
Expression of the transforming growth factor‐α gene by human eosinophils is regulated by interleukin‐3, interleukin‐5, and granulocyte‐macrophage colony‐stimulating factor
Authors: Brach Marion A. , Sott Claudia , Kiehntopf Michael , Herrmann Friedhelm 
Published: March 2007

AbstractTransforming growth factor (TGF)‐α is a pleiotropic polypeptide which mediates a variety of tissue‐specific cellular responses such as induction of proliferation, cell migration, vascularization, and formation of extracellular matrix. TGF‐α is produced by certain tumor cells and embryogenic tissues, as well as by normal cells of different origin. Within the granulocytic lineage. TGF‐α production has been shown in promyelocytic leukemia cells induced to differentiate, as well as in blood eosinophils of patients with the idiopathic hypereosinophilic syndrome. The present study was carried out in order to examine expression of the TGF‐α gene in polymorphonuclear (PMN) and mononuclear (MN) blood cells of normal healthy donors. While MN and neutrophilic PMN failed to synthesize TGF‐α transcripts and protein, eosinophils constitutively exhibited TGF‐α transcripts accompanied by the release of immunoreactive TGF‐α protein. Exposure of PMN and MN cells to the leukocyte‐activating cytokines interleukin (IL)‐3, IL‐5, and granulocyte‐macrophage colony‐stimulating factor resulted in a several‐fold increase of TGF‐α mRNA expression and protein release by eosinophils, but not by neutrophils and MN cells. PMN and MN were insensitive to induction of TGF‐α release by IL‐8 and granulocyte colony‐stimulating factor. These results point to a functional role of eosinophils in disorders characterized by unbalanced TGF‐α production such as disease states associated with abnormal matrix formation and neovascularization which may be explained by the present demonstration of TGF‐α production in these cells.
Protein‐G binding material from synovial fluid of rhematoid arthritis patients induces unorthodox autoantibodies (IgG1 rheumatoid factor) in NZB, NZW and (NZB x NZW)F1 mice
Authors: Abedi‐Valugerdi Manuchehr , Ridderstad Anna , Lettesjö Helene , Ström HÅKan , Möller Erna 
Published: March 2007

AbstractOur previous studies have demonstrated that injection of rheumatoid arthritis (RA) synovial fluid (SF) induces a marked increase mainly of IgG1 antibody‐producing cells in autoimmune disease prone (NZB X NZW)F1 mice but not in CBA mice. In the present study, the in vivo effect of RA‐SF on autoantibody production was tested in different strains of mice. Injection of RA‐SF induced the production of unorthodox autoantibodies (IgG1 rheumatoid factor, RF) in young (NZB X NZW)F1 mice as well as in their parental strains NZB and NZW, but not in normal mice (CBA) or in mice with severe combined immunodeficiency, indicating that the response is not caused by a conventional immune response against RA‐SF material. IgG1 RF production was rapidly induced and reached high levels already on day 7 and lasted for more than 90 days. The induction of IgG1 RF was not the result of polyclonal activation, since RA‐SF did not stimulate the production of other antibodies, such as autoantibodies against double‐stranded DNA, bromelain‐treated mouse red blood cells, myosin, transferrin, cytochrome c, thyroglobulin or myoglobin or antibodies reactive with the hapten TNP. To elucidate the identity of the active substance in RA‐SF, responsible for IgG1 RF production, bound and unbound material of RA‐SF, eluted from a protein‐G column was injected into (NZB X NZW)F1 mice. Only the protein‐G binding material was active, indicating that the effect is mediated by autoantibodies or immune complexes in the synovial fluid. Further studies demonstrated that identical concentrations of protein obtained from a pool of normal human IgG or SF from seronegative RA and non‐RA arthritides patients did not contain the same activity.
Proteolytic cleavage of CR1 on human erythrocytes in vivo: evidence for enhanced cleavage in AIDS
Authors: Pascual Manuel , Danielsson Carina , Steiger Gertraud , Schifferli Jürg Alfred 
Published: March 2007

AbstractThe number of complement receptor type 1 (CR1; CD35) on human erythrocytes (E) decreases during normal in vivo aging. Patients with acquired immunodefiziency syndrome (AIDS) have an acquired deficiency of CR1 on E. The possible mechanisms responsible for the loss of CR1 from E include the release of small vesicles from the E membrane and proteolytic cleavage of CR1. When compared to E of normal donors and of asymptomatic human immunodeficiency virus HIV+ subjects, E of patients with AIDS had fewer CR1/E (p < 0.001), but had the same number of two glycosylphosphatidyl‐inositol‐anchored proteins, decay‐accelerating‐factor (DAF) and CD59. When compared to young E, old E separated by density gradients on Percoll had fewer CR1 [six normal subjects, mean loss: 50.4 ± 4.9 (SEM) %], DAF (34.4 ± 1.2%) and CD59 (34.5 ± 2.7%). The loss of CR1 was significantly higher than the loss of DAF and CD59 (p < 0.02). In vitro, ATP depletion of E is responsible for the release of vesicles from the E surface, a reaction that has been called in vitro aging. CR1, DAF and CD59 were lost on ATP‐depleted E; however, the loss of CR1 and DAF were identical (six experiments, mean loss for CR1: 28.7 ± 2.7%, DAF: 26.3 ± 4.6% and CD59: 20.5 ± 4%). Thus, the release of vesicles from E cannot explain the specific loss of CR1 in patients with AIDS and would explain only incompletely the loss of CR1 during in vivo aging. In vitro experiments indicated that CR1 was more sensitive to trypsin and papain cleavage than DAF and CD59. Enhanced chemiluminescence Western blotting, using a monoclonal antibody (E11) recognizing fragments of CR1 down to 43 kDa on E exposed to trypsin or papain, indicated that normal E bear fragments of CR1, which are not found on polymorphonulcear leukocytes or on CR1‐bearing vesicles in urine. The relative amount of these fragments was increased in patients with AIDS. Taken together these data suggest that the specific loss of CR1 on E in AIDS is due to proteolytic cleavage. The loss of CR1 during in vivo aging also involves proteolytic cleavage, although part of the loss might be explained by other mechanisms including the release of vesicles by E.
Interleukin‐7 regulates c‐myc expression in murine T cells and thymocytes: a role for tyrosine kinase(s) and calcium mobilization
Authors: Seckinger Philippe , Milili Michèle , Schiff Claudine , Fougereau Michel 
Published: March 2007

AbstractInterleukin‐7 (IL‐7) was originally identified as a pre‐B cell growth factor whose proliferating activity has been extended to numerous target cells including T lymphocytes. We investigated c‐myc mRNA expression, an oncogene associated with proliferation, in the murine T cell line D10 G4.1 and freshly isolated thymocytes since both target cells proliferate in response to IL‐7. We find that blockade of the tyrosine kinase pathway by genistein, a potent tyrosine kinase inhibitor, inhibits both IL‐7‐dependent D10 G4.1 cell proliferation and c‐myc mRNA expression which appears to involve de novo mRNA synthesis and to be under the control of short‐lived protein repressor(s). We have also examined possible signal transduction pathways which might regulate c‐myc mRNA expression in the murine T cell line. IL‐7 biological activity is not affected by stimulation of the protein kinase C pathway by phorbol esters. Thus, IL‐7 regulates c‐myc mRNA expression in a protein kinase C‐independent manner and these data are strengthened by protein kinase C depletion which does not modify IL‐7 c‐myc mRNA responsiveness. In contrast and independent of protein kinase C activation, intracellular calcium mobilization by means of ionomycin reduces IL‐7 induction of c‐myc mRNA expression and may represent a physiological mechanism whereby IL‐7 bioactivity is regulated. The activity of IL‐7 on c‐myc mRNA expression has been extended to freshly isolated thymocytes and we find a synergistic effect of IL‐7 with concanavalin A. Taken together our results illuminate the molecular mechanism of IL‐7 c‐myc induction in the T lineage by ascribing a role for tyrosine kinase and increase in intracellular calcium in both IL‐7 induced gene induction and cell proliferation.
In vitro development of B cells and macrophages from early mouse fetal thymocytes
Authors: Péault Bruno , Khazaal Ibrahim , Weissman Irving L. 
Published: March 2007

AbstractThe developmental potentialities of early mouse fetal thymocytes were analyzed by in vitro culturing cell suspensions obtained from 12–15‐gestational day thymus in contact with a bone marrow stroma clonal cell line that supports pre‐B and myeloid cell differentiation. B cell and macrophage development from fetal thymocytes was observed at all fetal stages tested, but limiting dilution analysis revealed that the frequency of cells forming colonies on bone marrow stroma is the highest in the fetal thymus at day 12, then dramatically decreases until day 15. These observations suggest that the thymus rudiment is seeded by multipotential precursor cells which are not immediately committed to T cell development in the thymic cellular environment.
Preferential pairing of T and B cells for production of antibodies without covalent association of T and B epitopes
Authors: Bellone Matteo , Karachunski Peter I. , Ostlie Norma , Lei Sijin , Conti‐Tronconi Bianca M. 
Published: March 2007

AbstractT cell from H‐2b mice recognize at least 12 sequence regions on the Torpedo acetylcholine receptor (TAChR) α, γ and δ subunits. Immunization of C57BL/6 mice with individual synthetic TAChR sequences known to contain CD4+ epitopes resulted in most cases (10 out of 12 peptides) in anti‐peptide antibody (Ab) production, indicating that short TAChR sequences contain both CD4+ and B epitopes.Immunization of C57BL/6 mice with a mixture of a CD4+ epitope peptide, from the TAChR or from an unrelated protein, plus another TAChR sequence forming a “pure” B epitope (Tα63–80), induced in most cases anti‐peptide Ab and CD4+ cell sensitization only against the peptide containing the CD4+ epitope. However, when the T epitope peptide Tα360–378 was co‐injected with the B epitope, Ab were also produced against the B epitope peptide. Injection of the individual peptides Tα360–378 and Tα63–80 at different and distant sites along the back of mice elicited sensitization of CD4+ cells and Ab production only against peptide Tα360–378.Therefore, when optimal cooperation between T and B cells occurs, spatial proximity but not covalent association of the B and the CD4+ epitope is necessary for production of Ab against the B epitope.
Preferential expression of interleukin‐12 or interleukin‐4 by murine bone marrow mast cells derived in mast cell growth factor or interleukin‐3
Authors: Smith Tracey J. , Ducharme Lori A. , Weis John H. 
Published: March 2007

AbstractIn this report we demonstrate that murine bone marrow cells cultured in either interleukin (IL)‐3 or mast cell growth factor (MGF, also known as c‐kit ligand and stem cell factor) differentially express cytokine genes. Bone marrow cells cultured in IL‐3 differentiate and proliferate, taking on a mucosal mast cell‐like phenotype. These cells express the IL‐4 gene. Bone marrow cells cultured in MGF take on a connective tissue mast cell‐like phenotype and possess transcripts for both of the subunits of the IL‐12 cytokine. Bone marrow cells cultured in both IL‐3 and MGF express the IL‐4 gene at lower levels than that seen for the IL‐3 culture alone, but do not possess IL‐12 gene transcripts. The level of IL‐12 subunit transcripts derived from the MGF‐derived bone marrow cells was compared to that found in splenocytes and activated macrophages, the only cells in which IL‐12 production has been previously documented. Both of the IL‐12 subunit transcripts were found, compared to a β‐actin control, to be present within MGF‐derived cells in the same if not higher quantities than the splenocyte or macrophage cultures. Mucosal mast cells have been previously implicated in the development of the T helper type 2 (TH2) T cell phenotype via their expression of IL‐4. The finding that the MGF‐derived connective tissue‐like mast cells possess IL‐12 transcripts suggests that the development of the TH1 T cell pathway may be positively influenced by this type of mast cell.
Bimodal distribution of Vβ2+CD4+ T cells in human peripheral blood
Authors: Clarke Gillian R. , Reyburn Hugh , Lancaster Fiona C. , Boylston Arthur W. 
Published: March 2007

AbstractThe distribution of T cells using the Vβ2 gene was studied in a group of 99 humans. The distribution of Vβ2+CD4+ levels was bimodal. Twelve individuals had levels of Vβ2+CD4+ less than 2% and 86 others had values greater than 5%. Only one individual had a value between 2% and 5%. The Vβ2 low (mean 1.3 ± 0.49) and Vβ high (mean 8.2 ± 1.65) phenotypes were stable. The Vβ low phenotype is inherited and not limited to HLA or T cell receptor Vβ gene complexes. The CD8Vβ2 levels of CD4Vβ2 low individuals are also low. The residual Vβ2+ T cells in Vβ2 low individuals were not anergic to Vβ2‐specific stimulation. These data are compatible with the effects of an endogenous superantigen.
A novel, complement factor H‐related regulatory protein expressed on the surface of human B cell lines
Authors: Erdei Anna , Julen Nathalie , Marschang Peter , Feifel Elisabeth , Kerekes Krisztina , Dierich Manfred P. 
Published: March 2007

AbstractComplement regulatory proteins present on the surface of various mammalian cells play an important role in controlling homologous lysis, by interacting with C3 (and usually C4). These proteins have a similar structural motif (“short consensus repeat”) (Reid, K.B.M., Bentley, R.D., Campbell, R.D., Chung, L.P., Sim, R.B., Kristensen, T. and Tack, B.F., Immunol. Today 1986. 7: 230), and the genes encoding them are members of the family of regulators of complement activation. Here we describe a hitherto unknown member of this family, a molecule expressed by B lymphoblastoid cells. This protein is recognized by polyclonal antibodies fo factor H and by MAH4, a monoclonal antibody reacting with the N‐terminal portion of factor H. The cell surface protein is built up of two disulfide‐linked chains of approximately 68 and 75 kDa. Biosynthetic labeling studies confirmed that it is synthesized by B cells only, but not by the investigated lines of other origin. When tested for its functional activity, this molecule was shown to act as cofactor for factor I‐mediated cleavage of fluid‐phase C3b to C3bi. The protein appears to be encoded by a 3.5‐kb mRNA, hybridizing with a cDNA probe coding for the N‐terminal portion of factor H. Due to its cross‐reactivity with anti‐H antibodies, cofactor activity for factor I and hybridization with factor H cDNA, despite its two‐chain composition, it is considered a factor H‐like protein.
Interleukin‐10 inhibits the primary allogeneic T cell response to human epidermal Langerhans cells
Authors: Péguet‐Navarro Josette , Moulon Corinne , Caux Christophe , Dalbiez‐Gauthier Catherine , Banchereau Jacques , Schmitt Daniel 
Published: March 2007

AbstractIn this study, we analyzed the effect of interleukin‐10 (IL‐10) on the primary allogeneic T cell response induced by human Langerhans cells (LC), the dendritic cells from epidermis. We showed that IL‐10 strongly inhibited the T cell response, provided it was added at the beginning of the mixed epidermal cell lymphocyte reaction (MELR). Proliferation of both CD4+ and CD8+ T cell subsets was affected by the cytokine. An inhibitory effect of IL‐10 on human LC allostimulatory function was evidenced by the fact that IL‐10‐preincubated LC, but not IL‐10‐preincubated T cells, can display inhibitory effect. LC treatment with IL‐10 partially inhibited the increase of HLA‐DR expression on cultured LC as the percentage of highly positive HLA‐DR cells was lower than that observed in the absence of the cytokine. IL‐10 inhibited T cell alloreaction induced by 2‐day‐cultured human LC which constitutively display high levels of HLA class II, as well as ICAM‐1 and LFA‐3 antigens. This suggests that the suppressive effect of the cytokine was not merely related to an impaired up‐regulation of these molecules. Addition of IL‐1 during the MELR potentiated the allogeneic T cell proliferation and could reverse, at least partly, the inhibitory effect of IL‐10. Collectively, these data indicate that IL‐10 can prevent the alloreaction induced by human dendritic cells, providing new insights into the potential clinical use of this cytokine.
Isolation of tumor cell‐specific single‐chain Fv from immunized mice using phage‐antibody libraries and the re‐construction of whole antibodies from these antibody fragments
Authors: Kettleborough Catherine A. , Ansell Keith H. , Allen Richard W. , Rosell‐Vives Elisabet , Güssow Detlef H. , Bendig Mary M. 
Published: March 2007

AbstractEnhanced expression of epidermal growth factor receptor (EGFR) occurs on a variety of malignant tissues thus making anti‐EGFR antibodies possible agents for the diagnosis and therapy of human tumors. Standard hybridoma technology has been used successfully to isolate anti‐EGFR antibodies from immunized mice and rats. This report demonstrates that phage‐antibody libraries are an alternative, and more versatile, method for isolating antibodies from immunized mice. Anti‐EGFR antibodies were isolated from phage‐antibody libraries constructed not only from the spleen of an immunized mouse but also from the draining lymph node of an immunized mouse and from in vitro immunized mouse cells. Two of the single‐chain Fv isolated from the phage‐antibody libraries were engineered to create partially humanized whole antibody molecules.