bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrimination of human CD4 T cell clones based on their reactivity with antigen‐presenting T cells
Authors: Wyss‐Coray Tony , Brander Christian , Frutig Karin , Pichler Werner J. 
Published: March 2007

AbstractIn this report, we describe the discrimination of human T cell clones based on their reactivity with activated T cells as antigen‐presenting cells (APC). CD4+ T cell clones specific for peptide P30 of tetanus toxin (amino acids 947–967) and restricted to the DP4 molecule were established and tested for proliferation to peptide presented either by peripheral blood mononuclear cells (PBMC), Epstein‐Barr virus (EBV)‐transformed B cells or major histocompatibility complex (MHC) class II‐expressing T cells. We found two sets of T cell clones: one set proliferated to peptide presentation by PBMC, EBV‐transformed B cell lines (EBV‐B cells) and MHC class II+ T cells (termed T‐responder clones), while the other set of clones was only stimulated to proliferate, if the peptide was presented by PBMC or EBV‐B cells, but not by T cells (T‐nonresponder clones). Nevertheless, these T‐nonresponder clones recognized P30 also on T cells, as revealed by Ca2+ influx. The discrimination of the clones was not due to different avidities of the T cell receptors (TcR) of individual clones for the MHC‐peptide complex as T‐responder and T‐nonresponder clones had similar dose‐response curves to P30 presented by fixed EBV‐B cell lines. Addition of cytokines [interleukin (IL)‐1, IL‐2, IL‐4 and interferon γ] did not change the proliferative response of the clones, which was consistent throughout an observation period of >4 months. T‐nonresponder clones, exposed to P30 on MHC class II‐expressing T cells, became not anergic, as they could be restimulated by P30 presented on EBV‐B cells. The measurement of a panel of T cell activation markers and adhesion molecules on T‐responder and T‐nonresponder clones revealed a higher expression of the CD28 molecule on the T‐nonresponder clones. The data suggest that freshly cloned T cells can be differentiated by peptide presentation on classical (PBMC, EBV‐B cells) or non‐classical APC (class II+ T cells), and that this discrimination is further underlined by different levels of adhesion molecules.
Kinetics of cytokine mRNA production in the brains of mice with progressive toxoplasmic encephalitis
Authors: Hunter Chris A. , Roberts Craig W. , Alexander James 
Published: March 2007

AbstractC57BL/10 ScSn (B10) mice infected orally with Toxoplasma gondii were killed on days 5, 10, 15, 20 and 30 post infection and their brains excised. These were either used to count total tissue cyst numbers or divided for RNA purification and histopathological studies. The first signs of inflammation were on day 10 post infection, before the appearance of cysts in the brain, and correlating with the appearance of activated astrocytes. These mice had a mild meningitis with areas of encephalitis. Small numbers of cyst stages were first observed in the brain on day 15 and by day 20 the cyst numbers had increased dramatically but were not always associated with inflammation. After this time point, total cyst numbers did not increase significantly though there developed a marked variation in tissue cyst size with larger cysts becoming more numerous. The use of the polymerase chain reaction to assist in the amplification of brain RNA allowed the characterization of the kinetics of cytokine production within the brains of these animals. Only IL‐1α was found to be expressed constitutively in control mice. Transcripts for other cytokines associated with activated monocytes, microglial cells and astrocytes [tumor necrosis factor (TNF)‐α and interleukin (IL)‐6] were present on day 10, (IL‐6) and day 15 (TNF‐α) post infection. Thereafter, these cytokines were present in all infected animals. Of the T cell‐associated cytokines, IL‐4, a characteristic product of the T helper (Th)2 cell subset, was detected on days 10 and 15, while granulocyte macrophage colony stimulating factor (GM‐CSF) which can be produced not only by this cell type but also by Th1 cells and CD8+ T cells, was also present on day 15 but not thereafter. Transcripts for interferon (IFN)‐γ, present from day 15 post infection, were probably produced by CD8+ T cells, as IL‐2 which would indicate Th1 cell involvement was only detected 30 days after infection. The continual presence of IFN‐γ and TNF‐α, cytokines with reported anti‐toxoplasmic activity, in the CNS of B10 mice throughout the latter half of the experimental period did not diminish the severity of infection. These results indicate that the CD4+ Th2 subset may allow a rapid rise in cyst numbers and so be important in determining susceptibility to toxoplasmic encephalitis.
Analysis of the roles of CD4+ and CD8+ T cells in autoimmune diabetes of NOD mice using transfer to NOD athymic nude mice
Authors: Yagi Hideki , Matsumoto Mitsunobu , Kunimoto Kikuko , Kawaguchi Junko , Makino Susumu , Harada Minoru 
Published: March 2007

AbstractThe NOD mouse, which spontaneously develops insulitis and overt diabetes, is a model of autoimmune type I diabetes mellitus. For the precise analysis of the roles of CD4+ and CD8+ T cells in the pathogenesis of this mouse, these subsets must be transferred into recipients that are completely free of T cells and pathological changes. We used athymic NOD nude mice, which congenitally lack mature T cells and are free of insulitis and hyperglycemia up to the age of 60 weeks, as recipients for this purpose. To the nude recipients we transferred either one of a highly purified CD4+ or CD8+ T cell subset derived from non‐diabetic female NOD mice; any in vivo increase in the contaminating T cell subsets was prevented by injecting the antibody homologous to it. Most of the T cell‐reconstituted recipients were treated with cyclophosphamide to promote the onset of overt diabetes. Transfer of the CD8+ T cell subset alone did not induce insulitis or hyperglycemia. In contrast, transfer of the CD4+ T cell subset alone produced insulitis, but not hyperglycemia, in all the recipients. However, the subsequent transfer of CD8+ T cells into CD4+ T cell‐reconstituted recipients induced severe insulitis and hyperglycemia in almost all the recipients. In these diabetic recipients, we observed severe damage of the pancreatic islets and the infiltration of a large number of CD8+ T cells into the remaining islets; insulin‐secreting β cells were no longer detected. These results suggest that CD4+ T cells play a predominant role in the development of insulitis and that CD8+ T cells migrate into the islets and are subsequently, with the aid of CD4+ T cells, differentiated into killer cells which act against β cells.
Protective effect of anti‐interleukin (IL)‐6 antibody against endotoxin, associated with paradoxically increased IL‐6 levels
Authors: Heremans Hubertine , Dillen Chris , Put Willy , Van Damme Jo , Billiau Alfons 
Published: March 2007

AbstractTwo rat monoclonal antibodies (6B4 and 20F3) against mouse interleukin (IL)‐6 were studied for their effects on the generalized Shwartzman reaction and on cytokine production elicited by endotoxin injections. Both antibodies were found to protect mice against the generalized Shwartzman reaction. Production of interferon and tumor necrosis factor in these animals, as assessed from serum levels, were not consistently affected by the antibody treatment, although rather increased levels were occasionally noted. Paradoxically, however, endotoxin‐induced serum levels of IL‐6 in anti‐IL‐6‐treated mice were consistently found to be markedly increased and also to persist for longer time periods. The more vigorous and persistent response may have been due to slower elimination, increased synthesis, or a combination of both. Endogenous production of IL‐6 in mice may be sufficiently large to supersede the neutralizing potential of an excess of antibody, as was evident from the fact that ascites fluid of the anti‐IL‐6‐producing 6B4 hybridoma was biologically active in the IL‐6 assay.
Distribution of interferon‐γ receptor in human tissues
Authors: Valente Guido , Ozmen Laurence , Novelli Francesco , Geuna Massimo , Palestro Giorgio , Forni Guido , Garotta Gianni 
Published: March 2007

AbstractInterferon‐γ (IFN‐γ) is produced by activated T lymphocytes and plays a regulatory role in immune responses. The nature and location of cells that express the IFN‐γ receptor (R) and respond to this lymphokine are not well documented. The distribution of human IFN‐γ‐R (HuIFN‐γ‐R) was, therefore, investigated in situ by immunohistochemistry, using affinity‐purified rabbit polyclonal antibodies directed against the extracellular domain of the receptor. In lymphoid organs, IFN‐γ‐R expression is restricted to the B cell areas of lymph nodes, adult and fetal spleen, tonsils, appendix, and mucosa‐associated lymphoid tissue of the small bowel. Macrophages and other reticular cells in lymphoid tissues and other organs are strongly positive for IFN‐γ‐R, whereas its expression was consistently negative in the cortical and medullary thymocytes. Two‐color flow cytofluorometric analysis of blood, lymph node, tonsil, spleen and thymus cells confirms that most B lymphocytes are IFN‐γ‐R positive, whereas T lymphocytes are negative. However, after in vitro activation, peripheral blood T cells become IFN‐γ‐R+. In non‐lymphoid organs, IFN‐γ‐R is expressed on endothelial cells of the medium‐ and small‐size vessels. In epithelial tissues, high expression of IFN‐γ‐R is detected on trophoblastic epithelium, glandular cells of stomach, ileum and colon, lung alveolar cells, salivary duct cells, renal tubular cells, and endometrial mucosa cells. Hepatocytes are weakly positive, while squamous epithelial cells are negative. The distribution of the HuIFN‐γ‐R is discussed in view of the known functions of IFN‐γ.
Limited heterogeneity of T cell receptor variable region gene usage in juvenile rheumatoid arthritis synovial T cells
Authors: Sioud Mouldy , Kjeldsen‐Kragh Jens , Suleyman Sel , Vinje Odd , Natvig Jacob B. , Førre Øystein 
Published: March 2007

AbstractThe aim of this study was to determine whether synovial fluid (SF) T cells in patients with juvenile rheumatoid arthritis (JRA) are restricted in their T cell receptor (TcR) gene repertoire. The quantitative polymerase chain reaction (QPCR) was used to compare the transcription of Vβ and Vα gene families in freshly isolated SF T cells, in interleukin‐2 receptor‐positive (IL‐2R+) T cells and in peripheral blood (PB) T cells from 18 patients. Significantly less Vβ families are detected in SF when compared with PB (p > 0.0003). The TcR Vβ gene usage by IL‐2R+ T cells was even less heterogeneous when compared with freshly isolated SF T cells (p > 0.0002). Freshly isolated SF T cells from the left and the right knees of four patients transcribed the same Vβ families. Furthermore, we demonstrate that in SF the distribution of certain TcR Vβ gene segments in CD4+ and CD8+ T cells differed from that in PB of the same patient.The TcR Vα usage was studied in IL‐2R+ T cells from six patients who had shown restriction in their SF TcR Vβ gene usage. Only two to five TcR α transcripts were detected in three of these patients while a broad TcR Vα usage was seen in the other three patients. Sequence analysis of the SF Vβ 20 cDNA clones generated from the IL‐2R+ T cells of two patients demonstrated an oligoclonal expansion. Taken together, our data could indicate an antigen‐ and/or superantigen‐driven expansion of selected T cells in the synovial compartment.
Restricted diversity of Vγ9‐JP rearrangements in unstimulated human γ/δ T lymphocytes
Authors: Delfau Marie‐Hélène , Hance Allan J. , Lecossier Denise , Vilmer Etienne , Grandchamp Bernard 
Published: March 2007

AbstractThe diversity of human peripheral blood γ/δ T cells is known to be limited by the preferential use of V genes coding for Vγ9 (usually linked to JP) and Vδ2. We show that the diversity of these cells is further limited at the junctional region. First, an identical rearrangement is found in 10%–30% of all γ/δ T cells which contain Vγ9‐JP rearrangements. Second, the vast majority of Vγ9‐JP rearrangements which are different from this predominant sequence have, nevertheless, the same length or code for variable regions whose length differs by only one amino acid (±1). Overall, 30%–50% of Vγ9‐JP rearrangements have a junctional region which encodes for a peptide with the amino acid sequence E VX EL, in which EV is predominantly, but not exclusively, encoded by the germ‐line Vγ9 sequence and EL is encoded by JP. The X amino acid is variable, but a glutamine is over‐represented. The diversity of the Vγ9‐JP repertoire is fairly constant in different individuals and at different ages, including before, during and after the post‐natal expansion of peripheral blood γ/δ T cells.
Passive transfer of experimental myasthenia gravis via antigenic modulation of acetylcholine receptor
Authors: Loutrari Heleni , Kokla Anna , Tzartos Socrates J. 
Published: March 2007

AbstractAntigenic modulation of acetylcholine receptor (AChR) is considered to contribute to the reduction of endplate AChR in myasthenia gravis (MG). Yet, the pathogenic significance of this mechanism is unclear. To investigate the in vivo role of AChR antigenic modulation we examined the ability of bivalent F(ab')2 and monovalent Fab fragments of monoclonal antibody (mAb) 35 to passively transfer experimental autoimmune MG (EAMG) in rats. mAb 35 which binds at the main immunogenic region (MIR) of the AChR causes severe EAMG without being involved in channel function. Compared to the intact mAb, F(ab')2 35 proved to be less potent but still capable of inducing moderate EAMG, whereas Fab 35 were totally ineffective. Furthermore, both intact and F(ab')2 35 induced mild EAMG in complement‐depleted rats. These results (a) provide evidence that antigenic modulation of endplate AChR is sufficient to generate passive transfer of EAMG and (b) further support the pathogenic potential of the anti‐MIR antibodies in MG.
Peptide motifs of closely related HLA class I molecules encompass substantial differences
Authors: Rötzschke Olaf , Falk Kirsten , Stevanović Stefan , Jung Günther , Rammensee Hans‐Georg 
Published: March 2007

AbstractThe peptides presented by major histocompatibility complex class I molecules adhere to strict rules concerning peptide length and occupancy by certain amino acid residues at anchor positions. Peptides presented by HLA‐A*0201 molecules, for example, are generally nonapeptides requiring Leu or Met at position 2 and an aliphatic residue, predominantly Val, at position 9. A closely related molecule, HLA‐A*0205, differing from the former at four amino acid residues, has a related but substantially different peptide motif. A*0205‐presented peptides are still nonapeptides, and position 9 is still aliphatic, although it is preferentially occupied by Leu instead of Val. Position 2 not only allows aliphatic residues but also polar ones. Occupancy at position 6, considered as an auxiliary anchor in A*0201, as well as non‐anchor residues at positions 3, 4, and 8 are relatively well conserved between the two peptide motifs. Thus, although a number of the T cell epitopes presented by the two HLA‐A2 forms is expected to be identical, a considerable number of epitopes should be different.
A new subpopulation of intestinal intraepithelial lymphocytes expressing high level of T cell receptor γδ
Authors: Tauchi Yoshihiko , Matsuzaki Goro , Takimoto Hiroaki , Yoshikai Yasunobu , Nomoto Kikuo 
Published: March 2007

AbstractThe murine intestinal epithelium contains T cell receptor (TcR) γδ‐bearing T cells in high frequency. In the present report, we showed that TcR γδ‐bearing intestinal intraepithelial lymphocytes (IEL) from C3H/He (H‐2k) mice can be divided into two subpopulations based on TcR expression level; a subpopulation with a remarkably high level of TcR expression and a subpopulation with a moderate level of TcR expression, designated as TcR γδhi IEL and TcR γδmod IEL, respectively. In flow cytometric analysis, the TcR γδhi IEL expressed a high level of TcR (mean fluorescence channel 518) when compared with the TcR level of TcR γδ+ T cells in other lymphoid organs (mean fluorescence channel 88). The TcR γδhi IEL were detected in IEL from mice of H‐2k and H‐2k/b haplotypes but not in H‐2b and H‐2d haplotypes. Vδ4, which was reported to be frequently expressed in IEL of H‐2k mice, was preferentially expressed by TcR γδhi IEL. These results suggested that the existence of the TcR γδhi population is related to the high frequency of Vδ4 in H‐2k mice.
Why is clonal deletion of neonatal thymocytes defective?
Authors: Signorelli Kathy , Benoist Christophe , Mathis Diane 
Published: March 2007

AbstractA major mechanism for establishing tolerance to some murine self antigens is clonal deletion of self reactive T cells in the thymus. This mechanism is responsible for the near absence of T cells displaying particular T cell receptor (TcR) Vβ in strains of mice that express the major histocompatibility complex class II E molecule and a protein encoded within the 3′ open reading frame (ORF) of certain endogenous mammary tumor viruses (Mtv). However, clonal deletion does not operate in these same strains during the first few days after birth. This defect could be explained by a difference in any (or any combination of) the three elements involved: the T cell, the thymic stromal cell(s) or the antigen. We have explored these different possibilities and have come to the conclusion that a lack of antigen is the most likely explanation. Yet, neonatal and adult thymi have quite similar levels of messenger ribonucleic acid corresponding to Mtv 3′ ORF.
Membrane region of surface IgM is not sufficient for transducing growth inhibitory signals in an immature B cell line WEHI‐231
Authors: Iwabuchi Naoto , Williams Douglas B. , Nguyen Hai P. , Wu Yongjian , Tisch Roland , Azuma Toshifumi , James Phillips M. , Hozumi Nobumichi 
Published: March 2007

AbstractThe murine B lymphoma line WEHI‐231 is representative of immature B cells. Like normal immature B cells, WEHI‐231 is susceptible to growth arrest following cross‐linking of surface IgM (sIgM). Previously, we have shown using a WEHI‐231 immunoglobulin (Ig) δ‐transfectant that sIgD cross‐linking failed to initiate growth arrest, in contrast to sIgM. In this report, we extend our research to investigate the structural requirement of Ig μ chain for regulating growth inhibition. Recombinant, chimeric Ig molecules δ/μm and μ/δm consisting of exons encoding extracellular δ and μ domains and membrane regions of different isotypes were constructed and introduced into WEHI‐231 cells. A similar approach was used for sIgG2b‐expressing transfectants. Our findings indicate that the μm region is not sufficient for regulation of growth inhibition in WEHI‐231 cells and suggest that additional extracellular region(s) of μ chain may be required for this response.
Correlation of calcineurin phosphatase activity and programmed cell death in murine T cell hybridomas
Authors: Fruman David A. , Mather Pamela E. , Burakoff Steven J. , Bierer Barbara E. 
Published: March 2007

AbstractLigation of T cell receptor/CD3 complexes induces programmed cell death, or apoptosis, in immature thymocytes and many T cell hybridomas. While it has been demonstrated that T cell receptor‐mediated apoptosis requires an increase in intracellular calcium concentration, the specific calcium‐dependent signalling events leading to cell death are poorly defined. We have previously shown that T cell receptor/CD3‐mediated induction of apoptosis in a murine T cell hybridoma is inhibited by the immunosuppressive drugs cyclosporin A (CsA) and FK506. Recently, it has been determined that these agents inhibit the activity of calcineurin, a calcium‐ and calmodulin‐dependent serine/threonine phosphatase. Using an assay which measures calcineurin activity in cell lysates, we find that calcineurin‐dependent dephosphorylation of a phosphopeptide substrate is potently inhibited in hybridomas treated with CsA or FK506. Drug dose‐response analyses indicate that the level of cellular calcineurin activity correlates closely with the ability of these cells to undergo apoptosis. Thus, calcineurin appears to be a critical mediator of T cell receptor/CD3 signalling leading to programmed cell death in T cell hybridomas.
Evidence for endocytosis of E‐selectin in human endothelial cells
Authors: Von Asmuth Eckhardt J. U. , Smeets Edgar F. , Ginsel Leo A. , Onderwater Jos J. M. , Leeuwenberg Jet F. M. , Buurman Wim A. 
Published: March 2007

AbstractE‐selectin is an inducible adhesion molecule on endothelial cells. The internalization of this glycoprotein was investigated on tumor necrosis factor (TNF)‐activated cultured human umbilical vein endothelial cells (HUVEC). Kinetics of intercellular adhesion molecule‐1 (ICAM‐1) were studied in parallel experiments. Internalization studies were performed with radioiodinated antibodies in an acid elution endocytosis assay, and by immunohistology; both approaches gave equivalent results. [125I]ENA1, a monoclonal antibody (mAb) specific for E‐selectin, was internalized at a rate of approximately 1.7% of the membranebound [125I]mAb per minute. In contrast, less than 0.1% of membrane‐bound [125I]RR1/1, an mAb specific for ICAM‐1, was internalized per minute. TNF‐activated HUVEC were immunostained and examined by light microscopy (LM) and electron microscopy (EM). LM revealed the presence of ENA1, but not RR1/1, after 30 minutes of incubation with these mAb in cytoplasmic vesicles, which were characterized as multivesicular bodies by EM. Without previous mAb exposure of the endothelial cells, both high amounts of E‐selectin and bovine serum albumin complexed to colloidal gold, used as a marker for fluid‐phase internalization, were detected in the same organelles, thus arguing against mAb interaction‐induced E‐selectin internalization. Furthermore, the amount of E‐selectin surface expression was not influenced by ongoing mAb presence, also arguing against mAb interference with normal E‐selectin kinetics.Taken together, these results indicate that TNF‐activated HUVEC constitutively internalize E‐selectin. Physiological significance of E‐selectin internalization in the regulation of E‐selectin membrane expression, and in clearing E‐selectin ligands from the circulation, needs further investigation.
Neurons and neuroblastoma as a source of macrophage colony‐stimulating factor
Authors: Nohava Kathrin , Malipiero Ursula , Frei Karl , Fontana Adriano 
Published: March 2007

AbstractAccumulation of macrophages in brain tissue as observed in nervous system injury may be due to local production of hematopoietic colony‐stimulating factors (CSF). The present work shows human neuroblastoma cells and murine neurons, namely granule cells of the cerebellum, to produce macrophage (M)‐CSF which guides expansion and differentiation of macrophage lineage cells. The mRNA‐encoding M‐CSF but not the respective protein is present in mouse brain including cerebellum. Neither granulocyte M‐CSF nor IL‐3 is produced by cerebellar neurons or neuroblastoma. By their production of M‐CSF, neurons may regulate the macrophage response and lead to local expansion and enhanced function of macrophages in inflammatory diseases of the central nervous system.