bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vχ gene segments rearranged in chronic lymphocytic leukemia are distributed over a large portion of the Vχ locus and do not show somatic mutation
Authors: Wagner Simon D. , Luzzatto Lucio 
Published: March 2007

AbstractThe structure of the human Vχ locus has been thoroughly investigated, but how the germ‐line Vχ gene segment repertoire is actually sampled in χ chain gene rearrangements is not known. In order to begin to answer this question we have polymerase chain reaction (PCR) amplified the rearranged Vχ genes from 26χ‐expressing cases of chronic lymphocytic leukemia (CLL), followed by cloning and sequencing of the PCR product. All four Vχ gene families were represented amongst rearranged genes. In 25 out of 32 cases, the sequence of the rearranged gene matches perfectly that of 1 of 11 different known germ‐line Vχ genes, indicating that no somatic mutation has occurred. Of the remaining 7 rearranged Vχ genes, 4 differ from known germ‐line genes by only one or two amino acid residues; and 3 differ from each other and from all known sequences by 5 or more residues, suggesting that somatic mutation has occurred in these 3 cases. We conclude that: (a) in at least three‐squarters of cases the rearranged genes are unmutated; (b) there is preferential usage of individual Vχ genes but not of Vχ gene families; and (c) the Vχ genes used are widely dispersed in the Vχ locus.
Complement enhances the elimination of soluble aggregates of IgG by rat liver endothelial cells in vivo
Authors: Bogers Willy M. J. M. , Van Rooijen Nico , Janssen Daniëlle J. , Van Es Leendert A. , Daha Mohamed R. 
Published: March 2007

AbstractIn the present study, we have investigated the role of complement (C) and possible C receptors present on rat liver endothelial cells (EC) in the clearance and tissue distribution of soluble aggregates of IgG (AIgG). To study the effect of elimination of AIgG by EC in vivo, Kupffer cell (KC)‐depleted rats were used, with or without an intact C system (These rats will be referred to throughout this report as EC‐rats.) In EC‐rats with an intact C system, clearance of AIgG (2000‐3000 kDa, 20‐27 IgG molecules/aggregate) occurred in a biphasic manner with a first T½(T1)of 9.4 ± 2.3 min and a second T½(T2) of 44.7 ± 16.0 min. In EC‐rats without an intact C system [cobra venom factor (COVF)‐treated group], clearance of AIgG was significantly delayed with a T1 of 25.3 ± 9.9 min (p 0.005) and aT2 of 124.5 ± 18.4 min (p 0.001). There were less degradation products of AIgG in the circulation in EC‐rats treated with COVF as compared to EC‐rats with an intact C system. Eight minutes after injection, 27.5 ± 11.6% of the injected AIgG was found in the livers of EC‐rats while 15.1 ± 3.2% was found in the livers of the COVF‐treated group. Double immunofluorescence studies indicated that AIgG in the liver was associated with EC in the rats with an intact C system. Clear deposits of C3 and lesser amounts of Clq accompanied the deposition of AIgG. In COVF‐treated EC‐rats, AIgG together with Clq was also associated with EC but no detectable C3 was seen. These data suggest clearance of AIgG via Fc and C receptors present on EC in vivo.
Characterization of T cell receptor assembly and expression in a Ti γδ‐positive cell line
Authors: Kuhlmann Jan , Caspar‐Bauguil Sylvie , Geisler Carsten , Rubin Bent 
Published: March 2007

AbstractTcell antigen receptor (TcR) heterodimers of both the Ti‐αβ and Ti‐γδ types are expressed at the surface of T cells noncovalently associated with the CD3 complex composed of the monomorphic chains γ, δ, ε and ξ. The structural relationship and assembly of the various components of this multimeric protein complex is still not fully understood.In this report, the human leukemic Tcell line Lyon which expresses a Ti‐γδ/CD3 complex, was characterized and compared to another human leukemic Tcell line Jurkat (Ti‐αβ/CD3). Membrane TCR−/CD3− variants of the Tcell Lyon were induced and found to produce all of the Ti/CD3 components, with the exception of Ti‐δ.Biochemical analysis indicated that: (1) Ti‐γ/CD3γ, δ, ε complexes were formed in the endoplasmic reticulum in the absence of Ti‐δ; (2) the CD3‐ξ chain did not associate with the Ti‐γ/CD3γδε complex and (3) the Ti‐δ chain was required for cell surface expression of the Ti‐γδ/CD3 complex. Introduction of Jurkat wild‐type Ti‐α cDNA into Lyon T cells resulted in Ti‐αβ/CD3 expression and abrogated Ti‐γδ/CD3 expression. In contrast, the expression of the Ti‐γδ/CD3 complex was not affected by transfection of a mutated Ti‐α cDN A into Lyon cells. The mutated Ti‐α chain formed complexes with Ti‐β and CD3γδε, but the CD3‐ξ; chain did not associate with these complexes. Taken together analysis of Lyon cells transfected with either wild‐type or mutated Ti‐α suggested that the CD3‐ξ, chain may have higher affinity for Ti‐αβ/CD3 complexes than for Ti‐γδ/CD3 complexes.
T cell receptor heterogeneity in γδ T cell clones from intestinal biopsies of patients with celiac disease
Authors: De Libero Gennaro , Rocci Maria Paola , Casorati Giulia , Giachino Claudia , Oderda Giuseppina , Tavassoli Kaveth , Migone Nicola 
Published: March 2007

AbstractIn celiac disease large numbers of γδ T lymphocytes infiltrate the intestinal epithelia. We have isolated intestinal γδ T cell clones from patients with celiac disease and have analyzed their T cell receptor repertoire. T cell lines and clones were obtained from jejunal biopsies of 14 celiac patients and 12 individuals without celiac disease. These were analyzed by staining with monoclonal antibodies against CD3, αβ and γδ T cell receptor, by Southern blot with γ and δ specific probes and by polymerase chain reaction using Vδ‐specific oligonucleotides. Intestinal γδ cells from patients with celiac disease differed from those of controls with normal jejunal histology in that Vδ1+ cells and Vδ Vδ2 cells were significantly increased. There was no evidence of the expansion of one or more clones expressing particular types of γδ T cell receptor.
Human T cell autoimmunity against myelin basic protein: CD4+ cells recognizing epitopes of the T cell receptor β chain from a myelin basic protein‐specific T cell clone
Authors: Saruhan‐Direskeneli Güher , Weber Frank , Meinl Edgar , Pette Martin , Giegerich Gerhard , Hinkkanen Ari , Epplen Jörg T. , Hohlfeld Reinhard , Wekerle Hartmut 
Published: March 2007

AbstractWe have investigated whether the normal immune system contains T cells that are able to recognize T cell receptor (TcR) determinants of autologous autoantigen‐specific T cells. The T cell clone HW. BP3, specific for myelin basic protein (MBP) was isolated from a healthy donor. HW.BP3 is restricted by HLA‐DR2a, and reacts to human MBP 139‐153. The expressed α β TcR genes of HW.BP3 were cloned and sequenced, and the sequences analyzed for potential T cell epitopes. Two synthetic peptides, one from the VDJβ junctional (β1) and one from theVβ region (β2) of the TcR of IIW.BP3, were used to select four TcR peptide‐specific T cell lines from the donor of HW.BP3. All anti‐TcR lines had the phenotype CD3+/CD4+/HLA‐DR+/CD25−/CD45RO−, and recognized the antigen in the context of HLA‐DR. Three anti‐TcR lines, which had been selected for reactivity to peptide pi, recognized exclusively this peptideβ1, restricted by HLA‐DR2b. One anti‐TcR line, selected for peptide (β2, responded to both peptides pi and P2 when presented by autologous blood mononuclear cells, but not by HLA‐DR2a‐ or HLA‐DR2b‐transfected L cells.All TcR peptide‐specific T cell lines were efficiently cytotoxic. They specifically lysed autologous macrophages or HW.BP3 line cells in the presence of exogenous peptide antigen. In contrast, HW.BP3 did not present endogenous TcR peptides to the anti‐TcR lines. The results demonstrate that the normal human immune system contains not only autoantigen‐specific T cells, but also T cells that recognize antigenic determinants of autologous autoreactive TcR.
The CD2 and CD28 adhesion molecules induce long‐term autocrine proliferation of CD4+ T cells
Authors: Costello Régis , Cerdan Chantal , Pavon Christine , Brailly Hervé , Hurpin Christian , Mawas Claude , Olive Daniel 
Published: March 2007

AbstractIn vitro human T lymphocyte activation requires two‐signal triggering delivered by lectins, phorbol esters or antibodies directed against surface molecules. Stimulation of adhesion molecules by CD2 and/or CD28 antibodies defines alternative activation pathways. Activation by CD2 + CD28 monoclonal antibodies induces high‐level, long‐lasting and monocyte‐independent proliferation of highly purified T cells. Limiting dilution cultures showed that CD28 in association with CD2 or CD3, without addition of exogenous cytokines, induced single‐cell proliferation. CD2 + CD28 stimulation induced long‐term interleukin (IL)‐2‐dependent autocrine proliferation of CD4+ T cell clones. We tried to elucidate this long‐term proliferation by evaluating cytokine secretion and cytokine dependency. CD28 associated to CD3 or CD2 induced high levels of IL‐2, tumor necrosis factor (TNF) and IL‐4 secretion for 10 days, in contrast to CD3 alone which induced only TNF secretion. Cytokines of the monocytic lineage were also secreted, such as colony‐stimulating factor‐1, granulocyte macrophage colony‐stimulating factor or IL‐1, the latter being more specific of CD2 + CD28 activation. Blocking antibodies confirmed the crucial role of IL‐2 in CD2 + CD28 activation. Anti‐IL‐4, anti‐IL‐7 receptor or anti‐TNF antibodies had no effect on proliferation. Stimulation with CD2 + CD28 induced long‐term autocrine (at least for IL‐2) proliferation for CD4+ T cells, with no evidence for the implication of another cytokine among those tested other than IL‐2. This represents a model for long‐term autocrine growth for non‐leukemic cells.
Isolation of an HLA‐A2.1 extracted human minor histocompatibility peptide
Authors: de Bueger Marleen , Verreck Frank , Blokland Els , Drijfhout Jan Wouter , Amons Reinout , Koning Frits , Goulmy Els 
Published: March 2007

AbstractPurified HLA‐A2.1 molecules obtained by affinity chromatography of 6 × 1010 Epstein Barr virus (EBV)‐transformed B lymphocytes were used in an attempt to isolate the human HLA‐A2.1‐restricted minor histocompatibility (H) peptides H‐Y and HA‐2. Fraction 18 of the high‐performance liquid chromatography (HPLC)‐separated HLA‐A2.1 peptide pool was found to contain the natural HA‐2 peptide. An HA‐2‐specific, HLA‐A2.1‐restricted cytotoxic T lymphocyte clone lysed HLA‐A2.1+ HA‐2− EBV‐transformed B lymphocyte cell lines reproducibly and in a concentration‐dependent fashion in the presence of fraction 18, but not in the presence of other HPLC fractions. By contrast, H‐Y sensitizing activity was not found in any fraction. Amino acid sequencing of peptide fraction 18 revealed a mixture of peptides with maximal length of nine amino acids, in which the presence of Leu at positions 2 and 9 was dominant. Surprisingly, the HA‐2 peptide could not be mimicked by any of the peptide mixtures synthesized according to the amino acid sequences found in fraction 18. Our failure to obtain the actual amino acid sequence of the human minor H peptide HA‐2 from a peptide pool with the established pattern for binding to HLA‐A2.1 may indicate that this CTL defined minor H peptide does not represent an abundant HLA‐A2.1 binding peptide.
Mercuric chloride down‐regulates T cell interferon‐γ Production in Brown Norway but not in Lewis rats; role of glutathione
Authors: Van Der Meide Peter H. , De Labie Miranda C. D. C. , Botman Caroline A. D. , Van Bennekom Wout P. , Olsson Tomas , Aten Jan , Weening Jan J. 
Published: March 2007

AbstractInjection of a low dose of mercuric chloride into Brown Norway (BN) rats caused a marked decrease in the concanavalin A (ConA)‐induced generation of interferon‐γ‐producing cells (IFN‐γ pc) in spleen cell cultures prepared 1 h after mercury administration. A second injection 48 h later caused a further diminution of IFN‐γ pc down to 30% of the number generated in splenocyte cultures of phosphate‐buffered saline (PBS)‐injected controls. Injection of Lewis rats with either one or two doses of HgCl2 revealed no inhibitory effect on splenic IFN‐γ production.The presence of the reduced form of glutathione (GSH) in the culture medium was found to be essential in these experiments. In the absence of GSH there was an overall 20‐fold reduction of the number of IFN‐γ pc in splenocyte cultures of normal or PBS‐injected rats, which was further reduced to a 60‐ to 70‐fold‐lower level in cultures of rats exposed to HgCl2. This mercury‐mediated extra reduction could be fully reversed with an excess (2 mM) of GSH in Lewis but not in BN splenocyte cultures. Since the bivalent Hg2+ ion is known to bind to and inactivate sulfydryl groups of proteins and low molecular weight thiols, most notably GSH, we investigated a possible role for thiols in IFN‐γ production. It was found that the generation of IFN‐y pc in normal BN and Lewis splenocyte cultures was strongly dependent on GSH or its precursor cysteine in the culture medium. Other thiol compounds were also effective but disulfides were completely inactive. Depletion of intracellular GSH in ConA‐stimulated splenocytes by buthionine sulfoximide (BSO), an inhibitor of de novo GSH biosynthesis, strongly inhibited the generation of IFN‐γ pc. The inhibitory effect of BSO was not abolished by the addition of interleukin‐2 (IL‐2), but was mimicked with antibodies directed to the IL‐2 receptor. The data stress the importance of GSH in the enhancement of IL‐2‐mediated IFN‐γ production and are most consistent with a model in which mercury interferes with T cell IFN‐γ production by affecting the intracellular availability of GSH. The strain‐specific susceptibility to mercury‐mediated inhibition of IFN‐γ production is discussed.
Evidence for a preferential Vβ usage by the T cells which adoptively transfer diabetes in NOD mice
Authors: Edouard Philippe , Thivolet Charles , Bedossa Pierre , Olivi Martine , Legrand Béatrice , Bendelac Albert , And Jean‐François Bach , Carnaud Claude 
Published: March 2007

AbstractNon‐obese diabetic (NOD) mice become spontaneously diabetic as a result of a genetically programmed autoimmune process mediated by autoreactive T lymphocytes and directed against β cell antigen(s). Studies dealing with T cell receptor (TcR) variable (V) gene usage by such autoreactive T lymphocytes have given contrasted results. Various reasons may explain these discrepancies: the multiplicity of antigenic epitopes putatively recognized by T cells, the ambiguity between specifically committed T cells and passenger lymphocytes homing randomly to the pancreas, the necessarily limited size of the T cell clone panels which have been analyzed for TcR rearrangements and, last but not least, the flexibility of T cell repertoires. To circumvent some of these difficulties, we have decided to concentrate upon the T cell population present in diseased animals and capable of transferring diabetes into young naive NOD recipients. This population, composed of CD4+ and CD8+ T cells, is presumably committed against the relevant β cell antigens and is the most likely to reveal a bias in V gene usage if such a bias does indeed exist.To find out whether certain Vβ genes are more frequently used than others by such pathogenic T cells, T lymphocytes from diabetic donors have been depleted in vitro of defined Vβ subsets before being reinoculated into permissive recipients. Out of four Vβ families probed under such conditions, three (Vβ8, Vβ5 and Vβ11 are neutral. Their absence neither increases nor reduces the final incidence of successful transfers, indicating that these gene segments are not preferentially used. In contrast, the depletion of Vβ6‐positiveT cells results in a severe reduction of transfers, suggesting that Vβ6 gene is used with a relatively high frequency by diabetogenic CD4+ and/or CD8+ T cells. To define more precisely which subset uses Vβ6 gene preferentially, we have performed mixing experiments with deleted and intact subsets. The results, based on disease transfer and insulitis severity, indicate that the Vβ6 bias affects predominantly the CD4+ subset. Thus, at variance with several studies concluding that V gene usage in NOD mice is heterogeneous, our present data suggest that disease transferring T cells use a relatively restricted set of Vβ genes.
T cell clones specific for p21 ras‐derived peptides: Characterization of their fine specificity and HLA restriction
Authors: Gedde‐Dahl Tobias , Fossum Beate , Eriksen Jon Amund , Thorsby Erik , Gaudernack Gustav 
Published: March 2007

AbstractPeptides corresponding to the mutated regions of the oneoprotein p21 ras are immunogenic and capable of eliciting HLA class II‐restricted T cell responses. Here we report studies on the fine specificity of four T lymphocyte clones (TLC) from a single donor, using various truncated peptides derived from the residues 6–19 of p21 ras and a panel of well‐characterized HLA homozygous cells as antigen‐presenting cells. Putative minimum peptides of nine or ten amino acids could be defined for each TLC. Two of the TLC recognized peptides presented by DR2, and the two others recognized peptides presented by DQ6. Some notable differences in the requirement for certain amino acids were seen between the DR‐and DQ‐restricted TLC. Thus, Ser at residue 17 was required for stimulation of the DQ6‐but not the DR2‐restricted TLC. Val at residue 8 was essential for stimulation of all TLC, whereas one of the DR2‐restricted TLC also required Val at residue 7. Some peptides which were nonstimulatory were still capable of binding to DQ6 molecules in peptide competition experiments. The results may be of importance for potential immunotherapy of cancer where transforming ras oncoproteins are involved.
RANTES and related chemokines activate human basophil granulocytes through different G protein‐coupled receptors
Authors: Bischoff Stephan C. , Krieger Martin , Brunner Thomas , Rot Antal , Tscharner Vincenz V. , Marco Baggiolini  , Dahinden Clemens A. 
Published: March 2007

AbstractChemotactic cytokines related to interleukin‐8 (IL‐8; CXC‐chemokines) or monocyte chemotactic protein‐1 (MCP‐1; CC‐chemokines) have been shown to stimulate human basophils, and are considered important tissue‐derived mediators of inflammation. We have studied the effects of four CC‐chemokines and show that MCP‐1, RANTES (regulated on activation, normal T expressed and secreted) and macrophage inflammatory protein‐lα (MlP‐lα) are potent basophil agonists inducing a rapid change of cytosolic free calcium ([Ca2+]i), the release of histamine and sulfido‐leukotrienes, and chemotaxis. MCP‐1 was the most potent stimulus of release, and the only chemokine that induced marked exocytosis in basophils without pretreatment with interleukin‐3. RANTES was the strongest stimulus of chemotaxis, but only a moderate stimulus of release. MIP‐lα elicited relatively weak chemotaxis and release responses, but was effective at considerably lower concentrations than MCP‐1 and RANTES. MIP‐1β, by contrast, despite its high homology to MlP‐lα, was totally inactive. Normodense human eosinophils, tested for comparison, responded in a similar fashion to RANTES and MIP‐lα, but were unresponsive to MCP‐1 and MIP‐lβ. All CC‐chemokines except MIP‐lβ induced a similar rapid and transient rise of [Ca2+]| that was sensitive to pertussis toxin, indicating that they activate basophils via G‐protein‐coupled receptors. Cross‐desensensitization experiments indicate that basophils bear different CC‐chemokine receptors. Some interact selectively with MCP‐1 or RANTES, while others are shared by RANTES and MlP‐lα.
CD20 monoclonal antibodies down‐regulate IgM at the surface of B cells
Authors: Bourget Isabelle , Breittmayer Jean‐Philippe , Grenier‐Brossette Nicole , Cousin Jean‐Louis 
Published: March 2007

AbstractThe CD20 molecule is a phosphoprotein expressed on the surface of B lymphocytes that plays a role in the regulation of B cell proliferation and differentiation. In this study it was found that monoclonal antibodies (mAb) directed to CD20 decrease the expression of IgM at the surface of normal human B lymphocytes and B cell lines. This effect was time‐dependent with a half‐time of about 5 h. Incubation of B cells with CD20 mAb B1 did not affect the steady‐state level of IgM mRNA, suggesting that it acts at a nontranscriptional stage. Phorbol esters also produced inhibitory effect on surface IgM expression. Staurosporine reversed both the phorbol ester‐ and the CD20‐induced down‐regulation. Genistein did not reversed the down‐regulation induced by the CD20 mAb Bl. CD20 most likely triggers a protein kinase C‐dependent pathway to down‐regulate slgM. CD20 mAb also counteracted the interleukin‐4 (IL‐4)‐induced up‐regulation of slgM. The ability of anti‐IgM to mobilize intracellular calcium was reduced in slgM down‐regulated cells, suggesting that B cells activation through the antigen receptor may be negatively regulated by CD20 and positively by IL‐4.
Antigen‐specific therapy of experimental myasthenia gravis with acetylcholine receptor‐gelonin conjugates in vivo
Authors: Urbatsch Ina L. , Sterz Raimund K. M. , Peper Klaus , Trommer Wolfgang E. 
Published: March 2007

AbstractRats suffering from experimental autoimmune myasthenia gravis (EAMG) induced by previous immunization with foreign acetylcholine receptor (AChR) were treated with AChR‐toxin conjugates using the plant toxin gelonin. This led to a marked improvement of clinical symptoms as well as a significant increase in functional AChR compared to untreated rats with EAMG as determined 6 to 10 weeks later. No therapeutic effect was observed after treatment with gelonin or AChR alone. The immune response to irrelevant control antigens was not altered by this treatment.