bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential activation of human basophils by anti‐IgE and formyl‐methionyl‐leucylphenylalanine. Indications for protein kinase C‐dependent and ‐independent activation pathways
Authors: Knol Edward F. , Koenderman Leo , Mul Frederik P. J. , Verhoeven Arthur J. , Roos Dirk 
Published: March 2007

AbstractUpon activation, basophilic granulocytes release inflammatory mediators such as histamine. We studied histamine release of human basophils (64.1 ± 9.6% pure) after cross‐linking of membrane‐bound IgE via anti‐IgE, or after binding of the chemoattractant formyl‐methionyl‐leucyl‐phenylalanine (fMLP).A variability in the extent of histamine release upon stimulation by either anti‐IgE or fMLP was found between donors. Kinetic studies revealed that the histamine release induced by anti‐IgE (t1/2 > 240 s) was more than 20‐fold slower than the almost instantaneous release upon stimulation with fMLP (t1/2 < 10 s). Differences in the cell activation pathways triggered by these stimuli were further analyzed with staurosporine, an inhibitor of protein kinase C (PKC) and with wortmannin, an inhibitor of a PKC‐independent pathway. Inhibition of PKC resulted in a partial inhibition of the anti‐IgE‐induced release, whereas the fMLP‐induced release was slightly potentiated. The anti‐IgE‐induced release was completely inhibited in the presence of wortmannin. This inhibitor too, had no effect on the fMLP‐induced release. We conclude that major differences exist in the signal‐response coupling between the anti‐IgE and fMLP‐induced histamine release in human basophils. The so‐called releasability of human basophils may be due to the availability of different cell activation pathways.
Vλ‐Jλ rearrangements are restricted within a V‐J‐C recombination unit in the mouse
Authors: Sanchez Pierre , Nadel Bertrand , Cazenave Pierre‐André 
Published: March 2007

AbstractThe murine λ gene locus is organized as follows: Vλ2‐Vλx‐Jλ2Cλ2‐ΨJλ4Cλ4‐Vλ1‐Jλ3Cλ3‐Jλ1Cλ1 where all segments have the same transcriptional orientation. The combinatorial process of gene recombination should allow the generation of eight distinct immunoglobulin light chains. We have therefore investigated the probability of obtaining such chains among the mature λ B cell repertoire. We analyze serum λ immunoglobulins and λ B cell clones induced by treatment with rabbit anti‐Δ antibodies coupled to LPS. Confirming previous data obtained by others, our results indicate that the rearrangements of Δ segments take place within each Vλ‐Jλ‐Cλ cluster, thereby defining a unit of recombination. Our results also provide no evidence for the use of undescribed segments as has been recently suggested by the finding of the Vλx segment.
Studies on the human T cell receptor α/β variable region genes. II. Identification of four additional Vβ subfamilies
Authors: Ferradini Laurent , Roman‐Roman Sergio , Azocar José , Michalaki Hélène , Triebel Frédéric , Hercend Thierry 
Published: March 2007

AbstractThe human T cell receptor (TcR) β chain gene segment diversity has been studied using the anchored‐polymerase chain reaction. Three hundred and fifty Cβ‐specific transcripts derived from peripheral lymphocytes were analyzed. Transcripts including V‐Dβ1‐Jβ2‐C2 sequences were found with a high frequency (> 10%), suggesting that “illegitimate” joinings may constitute a cis‐complementing rearrangement mechanism capable of substantially increasing the TcR β chain combinatorial diversity. Twelve previously undescribed Vβ gene segments have been identified. Five of them delineate four novel Vβ subfamilies (Vβw21: two members, Vβw22, 23, 24: one member) which all have a murine homologue. The additional seven gene segments belong to the Vβ5, Vβ6, Vβ12 and Vβ13 subfamilies. In addition, the sequences of two known Vβ7 and Vβ9 gene segments have been extended. Together, the present data support the view that the contribution of the β chain combinatorial diversity to the TcR α/β variability has not yet been fully appreciated.
Complement enhances the clearance of large‐sized soluble IgA aggregates in rats
Authors: Bogers Willy M. J. M. , Stad Robert Kees , Janssen Danieulle J. , Rits Michel , Bazin Hervé , van Es Leendert A. , Daha Mohamed R. 
Published: March 2007

AbstractIn the present study the involvement of the complement system (C) in the clearance of soluble IgA aggregates in the rat was studied. Monoclonal monomeric IgA (mIgA) antibody (which does not activate C) or aggregated polymeric IgA (aIgA; which activates C) were administered intravenously to phosphate‐buffered saline‐treated and complement‐depleted [Cobra venom factor (CVF)‐treated] rats and assessed for clearance from the circulation. In control rats, mIgA was cleared in a biphasic fashion with a first half‐life (T1/2) of 29.5 ± 14.2 min and a second T1/2 of 230 ± 176 min. No differences were observed in clearance of mIgA in CVF‐treated rats as compared to PBS‐treated rats. In PBS‐treated rats, aIgA with a size between 20 S and 150 S disappeared very rapidly from the circulation with a first T1/2 of 1.1 ± 0.4 min and a second T1/2 of 23.2 ± 11.3 min. In CVF‐treated rats the clearance of aIgA was significantly delayed as compared to that in control rats, namely with a first T1/2 of 7.3 ± 2.6 min and a second T1/2 of 64.2 ± 19.4 min.Immunohistochemical studies of the liver (which is the main site of clearance of aIgA) revealed that Kupffer cells (KC) are mainly responsible for the uptake of aIgA. Furthermore, in PBS‐treated rats aIgA deposition was accompanied by C3 deposition in the KC. In CVF‐treated rats, the percentage of KC containing aIgA was significantly lower during the first 16 min after aIgA administration as compared to PBS treated rats. In addition no detectable C3 was found in KC of CVF‐treated rats. These results indicate that KC play an important role in the clearance of large molecular weight IgA in rats and that C facilitates the clearance of these complexes from the circulation.
CD77: an antigen of germinal center B cells entering apoptosis
Authors: Mangeney Marianne , Richard Yolande , Coulaud Dominique , Tursz Thomas , Wiels Joëlle 
Published: March 2007

AbstractWe have previously reported that a neutral glycolipid (globotriaosylceramide; Gb3) was specifically expressed on Burkitt's lymphoma cells and on a subset of germinal center tonsillar B lymphocytes. Recently the Gb3 molecule was recognized as a new B cell differentiation antigen and now defines the CD77 cluster. Here we report an extensive phenotypic and functional characterization of the tonsillar CD77+ B lymphocytes. These cells have a low buoyant density and are thus purified using a Percoll gradient. They express various B cell antigens such as CD19, CD20, CD21, CD22 and CD40, as well as the adhesion molecules LFA‐1, LFA‐3 and CD44. They are positive for surface IgM and negative for surface IgD. Although these results suggest a phenotype of activated B cells, the CD77+ cells are negative for the classical activation antigens: CD23 (the low‐affinity Fc receptor for IgE), CD25 [the interleukin (IL) 2 receptor α chain] and CD71 (the transferrin receptor). Proliferation and protein synthesis of CD77+ cells was measured after stimulation with a range of mitogens and IL. None of the agents tested are able to induce proliferation and protein synthesis with the exception of a combination of recombinant IL 4 plus anti‐CD40 antibody. When examined by electron microscopy, CD77+ B lymphocytes present a morphology similar to that of cells undergoing programmed cell death, also called apoptosis (i.e. chromatin condensation, nuclear fragmentation, membrane blebbing). As shown by direct examination of DNA, these CD77+ cells are indeed in the process of apoptosis. Treatment of the CD77+ cells by recombinant IL 4 and anti‐CD40 antibody prevents apoptosis. All these results suggest that the CD77 molecule defines a B lymphocyte maturation pathway, specific for germinal center, where the cells undergo programmed cell death.
Normal serum immunoglobulins influence the numbers of bone marrow pre‐B and B cells
Authors: Sundblad Anne , Marcos Miguel , Huetz Francois , Freitas António , Heusser Christoph , Portnoi Denis , Coutinho António 
Published: March 2007

AbstractThe homeostatic mechanisms controlling B lymphocyte output from bone marrow are not well understood. The present experiments evaluated putative influences of circulating immunoglobulins (Ig) on bone marrow (BM) pre‐B and B cell populations. Injections into normal mice of Ig isolated from normal mouse serum, resulted in a dose‐dependent and reversible reduction in numbers of BM B lineage cells, in particular of small B220+ surface IgM− cells. Maximal effects were observed upon injection of isologous polyclonal Ig and were independent of mature T cells. These results suggest a feedback modulation of peripheral Ig on cellular activities in BM B lineage compartments, mediated by mechanisms that seem to involve the variable regions of the Ig molecule.
Direct involvement of CD7 (gp40) in activation of TcRγ/δ+ T cells
Authors: Carrel Stefan , Salvi Suzanne , Rafti Fiorella , Favrot Marie , Rapin Christophe , Sekaly Rafick Pierre 
Published: March 2007

AbstractIn this study we reported that on T cell receptor (TcR)γ/δ+ cells from three cell lines Peer, MOLT‐13 and ICRF‐1, the T cell antigen CD7 (gp40) can be directly involved in the activation process. This is shown by a rapid increase in cytoplasmic free calcium after stimulation of these cells with an anti‐CD7 monoclonal antibody (mAb). Activation through CD7 was further confirmed by measuring the production of interleukin 2 in ICRF‐1 cells stimulated with anti‐CD7 mAb. In addition induction of mRNA for tumor necrosis factor (TNF)‐α and TNF‐β in Peer and for granulocyte‐macrophage‐colony‐stimulating factor in MOLT‐13 was observed in these anti‐CD7‐stimulated cells. The same anti‐CD7 antibody was unable to activate TcR α/β+ Jurkat cells or normal resting peripheral blood T lymphocytes. We further showed that normal resting TcR γ/δ+ cells were likewise activated via the CD7 molecule. TcR γ/δ+ cells obtained from a patient with acute lymphoblastic leukemia 3 months after autologous bone marrow transplantation were induced to proliferate, as measured by [3H]thymidine incorporation after stimulation with anti‐CD7 mAb but not with anti‐CD3 mAb. Interestingly TcR α/β+ cells from the same donor tested in parallel were not stimulated by anti‐CD7 but by anti‐CD3 mAb. In essence these findings contribute to the idea that on TcR γ/δ+ cell, the CD7 antigen could play an important role during T cell differentiation.
Increased frequency of interleukin 4‐producing T cells as a result of polyclonal priming. Use of a single‐cell assay to detect interleukin 4‐producing cells
Authors: Seder Robert A. , le Gros Graham , Ben‐Sasson S. Z. , Urban Joseph , Finkelman Fred D. , Paul William E. 
Published: March 2007

AbstractA limiting dilution assay capable of detecting interleukin 4 (IL 4) production by a single cell has been developed. This assay is based on the stimulation of T cells, in the presence of IL 2 (5 U/ml), with anti‐CD3 antibody bound to the surface of Terasaki wells. Cells of the IL 4‐selective indicator line, CT.4S, are added 24–36 h later and IL 4 production is determined based on their survival 24–48 h thereafter. A frequency of 0.98 was obtained for IL 4 production by T cells of the D10.G4 cell line. T cells from naive donors capable of producing IL 4 in response to anti‐CD3 plus IL 2 were quite rare, with a frequency in four experiments ranging between 0.0003 and 0.0018. Treatment of mice with polyclonal activators known to increase the IL 4‐producing capacity of T cells when assayed in bulk culture caused striking increases in the frequency of IL 4‐producing cells. Similarly, culturing cells in vitro with anti‐CD3, IL 2 and IL 4 for 5 days caused a marked increase in the frequency of cells capable of producing IL 4, to 0.031.IL 4 production by individual T cells is dependent upon IL 2. Thus, in naive T cell populations, the frequency of IL 4‐producing cells in response to stimulation with anti‐CD3 in the absence of IL 2 was below the limit of detection. T cells from primed donors showed a striking inhibition in the frequency of IL 4‐producing cells in response to anti‐CD3 when IL 2 was not present. The availability of a simple assay to measure the frequency of cells capable of producing IL 4 should have substantial utility in allowing the evaluation of conditions that regulate IL 4 production in vivo and in vitro.
Analysis of T cell reactivities to phosphorylcholine‐conjugated hen egg lysozyme in C57BL/6 mice: hapten‐conjugate specificity reflects an altered expression of a major carrier epitope
Authors: Jang Yong‐Suk , Lim Kwang H. , Kim Byung S. 
Published: March 2007

AbstractWe have selected several different T cell hybridoma clones reactive to hen egg lysozyme (HEL) conjugated to phosphorylcholine (PC) after fusion of PC‐HEL‐primed C57BL/6 lymphocytes with BW5147 parent cells. These hybridoma clones preferentially recognize PC‐HEL over unconjugated HEL, but not other carrier molecules conjugated with the same hapten. All the PC‐HEL‐reactive clones are similarly responsive to not only p‐azobenzenearsonate (ABA)‐conjugated HEL (ABA‐HEL) but also to a variety of other diazotized hapten‐HEL conjugates. However, these clones are not stimulated by fluoresceinated or dinitrophenylated HEL beyond the level of HEL carrier alone. Therefore, the type of hapten linkage (diazonium) to the carrier molecule appears to affect T cell recognition. The hybridoma clones apparently recognize the carrier molecule alone, although the level of stimulation is relatively low compared to that induced by either PC‐HEL or ABA‐HEL. Interestingly, HEL unfolded by S‐carboxymethylation is capable of stimulating the hybridomas to a level comparable to that obtained with PC‐HEL. T cell recognition of the unfolded HEL is independent of antigen processing, which is different from that of PC‐HEL. The peptide sequence corresponding to the amino acids 81–93 of HEL appears to contain the epitope region for the hybridoma clones based on testing stimulation activity with synthetic peptides. Previously, the peptides including this region (81–96) have been reported as the determinant recognized by T cells derived from C57BL/6 mice after immunization with an HEL peptide (HEL 13–105) but not with native HEL. These results suggest that a hapten conjugation via diazonium linkage modifies antigen presentation and consequently the presentation of the major T cell epitopes similar to that of the HEL fragment.
Immunotherapeutic elimination of syngeneic tumors in vivo by cytotoxic T lymphocytes generated in vitro from lymphocytes from the draining lymph nodes of tumor‐bearing mice
Authors: Lynch David H. , Miller Robert E. 
Published: March 2007

AbstractThe draining lymph nodes (LN) of mice injected with viable syngeneic tumor cells contain populations of lymphoid cells which are capable of generating functional cytotoxic T lymphocytes (CTL) during an in vitro culture period without the need of secondary stimulation with irradiated tumor cells or addition of exogenous cytokines. Intravenous injection of as few as 2.5 × 106 tumor‐reactive effector cells generated using this protocol effectively eliminated challenges of tumor cells at distal skin sites, whereas injection of cultured control lymphoid cells was ineffective at rejecting tumor challenges. The anti‐tumor CTL generated from the draining LN of C57BL10 mice immunized with viable syngeneic tumor cells were found to be specific for the tumor used for immunization both in vitro and in vivo. Phenotypic analysis of the cells responsible for tumor elimination (both in vitro and in vivo) demonstrated the anti‐tumor effector cells to be CD4−CD8+ asialo GM NK1.1−. Finally, anti‐tumor CTL generated during the short in vitro culture period were able to effectively reject pre‐existing tumors in vivo in a systemic fashion. These data indicate that the generation of tumor‐reactive CTL from the lymphoid cells contained in the LN draining the site of a tumor may provide a valuable source of effector cells which can be used in the immunotherapeutic treatment of cancer.
Class II‐restricted IgG2ab‐specific T cells recognize a signal‐minus form of the V‐CH3b antigen
Authors: Bikoff Elizabeth K. 
Published: March 2007

AbstractTo study the question when and where self peptides become associated with major histocompatibility complex class II molecules for tolerance induction, we recently developed a system in which the intracellular site(s) of antigen expression could be manipulated using gene cloning techniques. We previously constructed a truncated IgG2a gene comprising a variable (V) domain and the C domain (not including the membrane exons) from the IgG2ab heavy (H) chain. The secreted form of the V‐CH3b protein was expressed at high levels under control of the Ig H chain enhancer in Ia+ B lymphoma cells and was efficiently recognized by class II‐restricted IgG2ab‐specific T cell hybrids. Here we describe a modified V‐CH3b gene construct in which the sequences encoding the signal peptide were deleted. A strong argument can be made that the signal‐less V‐CH3b protein is predominantly expressed in the cytosol. We show that transfected L cell lines expressing the signal‐less form of the V‐CH3b protein can stimulate class II‐restricted IgG2ab‐specific T cells. Cell mixing experiments indicate that this response cannot be due to passive uptake of soluble antigenic peptides released into culture supernatants. These experiments demonstrate that a cytoplasmic protein having no obvious means of reaching the cell surface can be presented to class II‐restricted T cells.
The mouse IgH 3′‐enhancer
Authors: Dariavach Piona , Williams Gareth T. , Campbell Kathryn , Pettersson Sven , Neuberger Michael S. 
Published: March 2007

AbstractA lymphoid‐specific transcription enhancer element has recently been identified at the far 3′ end of the rat immunoglobulin heavy chain (IgH) locus. Sequence analysis presented here reveals that this enhancer is flanked by a 350‐bp invert repeat, giving a structure reminiscent of a transposable element. We therefore screened for the equivalent enhancer in the mouse to determine whether its presence was conserved during evolution. A mouse homologue was indeed identified and is located 16 kb downstream of the Cα1 exon. It is also flanked by invert repeats and these are not repeated throughout the genome. The mouse and rat enhancers retain high sequence homology. As regard activity, the IgH 3′‐enhancer is lymphoid specific. However, this activity was detected in two plasmacytoma lines tested but not in two B cell lymphomas nor in HeLa cells suggesting that the enhancer may only play a stage‐specific role during lymphocyte differentiation. As regards function within the IgH locus, we found that inclusion of the mouse IgH 3′‐enhancer (in addition to the intron‐enhancer) on μ gene expression plasmids effected a small increase in μ mRNA levels in stable plasmacytoma transfectants.
Vaccination of class I major histocompatibility complex (MHC)‐restricted murine CD8+ cytotoxic T lymphocytes towards soluble antigens: immunostimulating‐ovalbumin complexes enter the class I MHC‐restricted antigen pathway and allow sensitization against the immunodominant peptide
Authors: Heeg Klaus , Kuon Wolfgang , Wagner Hermann 
Published: March 2007

AbstractIn vivo induction of anti‐ovalbumin (OVA) cytotoxic T cell responses was brought about in an MHC class I‐restricted fashion by immunizing H‐2b mice with OVA in immunostimulating complexes (ISCOM). ISCOM formation with the hydrophilic soluble protein OVA was achieved upon unmasking hydrophobic protein domains by treatment at low pH values. The effector cells induced were MHC restricted, specific for the immunodominant peptide of OVA (258–276), and expressed the CD8+CD4− phenotype. These results suggest that ISCOM‐based vaccines may be useful to direct hydrophilic soluble antigens into the MHC class I presentation pathway in order to vaccinate CD8+ T lymphocytes.
Transcripts encoding mouse CD44 (Pgp‐1, Ly‐24) antigen: strain variation and induction by mitogen
Authors: Haegel Hélène , Ceredig Rhodri 
Published: March 2007

AbstractThe cell surface molecule CD44, thought to be a cell surface receptor for hyaluronic acid, is expressed by thymocytes and peripheral T cells. Following T cell activation with mitogens or antigens, surface expression of CD44 increases. This increase in CD44 cell surface expression has been used as a means of identifying memory T cells in vivo. In this report, using Northern analysis, we have quantitated mouse CD44 transcripts in thymocytes and a cloned T hybridoma cell line. In contrast to a recent report by Nottenburg et al. (Proc. Natl. Acad. Sci. USA 1989. 86: 8521), we show that in all instances CD44 transcripts are polyadenylated. In all cells studied, three major mRNA species of approximately 4.5, 3.5 and 1.6 kb are detected. After stimulation with phorbol 12‐myristate 13‐acetate (PMA), there is a de novo protein synthesis‐dependent increase in the level of CD44 transcripts. The increase in CD44 transcripts precedes the increase in cell surface expression. In contrast to CD44, PMA stimulation results in a decrease in the level of Thy‐1 transcripts. Thymocytes from different mouse strains vary in their level of CD44 cell surface expression and Northern analysis indicates that this mouse strain variation correlates with a corresponding difference in the level of CD44 transcripts.
Induction of the interleukin 1 receptor antagonist protein by transforming growth factor‐β
Authors: Turner Martin , Chantry David , Katsikis Peter , Berge Ann , Brennan Fionula M. , Feldmann Marc 
Published: March 2007

AbstractTransforming growth factor‐β1 (TGF‐β1) mediates many immunosuppressive effects on immune cells and can inhibit the production of tumor necrosis factor and interleukin 1 (IL 1). However, TGF‐β1 can stimulate the production of IL6 and platelet‐derived growth factor, indicating that TGF‐β1 initiates complex effects on the production of cytokines. In this report we show that treatment of peripheral blood monocytes with TGF‐β1 leads to the induction of a recently described IL1 receptor antagonist protein (IRAP). The effect of TGF‐β was both dose and time dependent. TGF‐β1 induced de novo synthesis of IRAP, as Northern blotting experiments indicated a rapid and transient induction of the mRNA encoding IRAP. The induction of IRAP suggests a potential mechanism by which some of the inhibitory effects of TGF‐β1 are mediated.
Characterization of the CAMPATH‐1 (CDw52) antigen: biochemical analysis and cDNA cloning reveal an unusually small peptide backbone
Authors: Xia Meng‐Qi , Tone Masahide , Packman Len , Hale Geoff , Waldmann Herman 
Published: March 2007

AbstractThe CAMPATH‐1 (CDw52) antigen has been purified from human spleen. The antigenic epitope is heat stable but sensitive to mild alkali treatment. Experiments with phosphatidylinositol‐specific phospholipase C indicate that it is anchored by a glycosylphosphatidylinositol (GPI) anchor. An N‐terminal sequence of 11 amino acids was determined, followed by an abrupt stop. Using short overlapping mixed oligonucleotide primers, cDNA synthesized from the mRNA of a human B cell line was amplified by the polymerase chain reaction. The product was used to isolate cDNA clones and the full amino acid sequence of the CAMPATH‐1 antigen was deduced. It consists of 37 amino acid residues plus a 24‐residue signal peptide. It has all the features expected for a GPI‐anchored membrane protein except that the predicted mature protein is remarkably short, comprising no more than 18 residues and possibly as few as 12 (depending on the GPI linkage site). Potential attachment sites for carbohydrate are present and it is shown that the antigen contains N‐linked oligosaccharide(s). This structure accounts for the known properties of the antigen, though the exact reasons why it is such a good target for cell lysis in vitro and in vivo are not yet clear.