bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of tyrosine phosphorylation in the interaction of cellular tyrosine kinases with the T cell receptor ζ chain tyrosine‐based activation motif
Authors: Osman Narin , Lucas Susan , Cantrell Doreen 
Published: March 2007

AbstractImmunoglobulin receptor family tyrosine‐based activation motifs (ITAM) define a conserved signaling sequence, EX2 YX2L/IX7YX2L/I, that mediates coupling of the T cell antigen receptor (TCR) to protein tyrosine kinases (PTK). In the present study, we explored the role of phosphorylation of the two ITAM tyrosine residues in the interactions of the motif with the PTK ZAP‐70 and p59fyn. The data show that the phosphorylation of a single tyrosine within the motif enables binding of p59fyn, whereas phosphorylation of both tyrosines within the motif is required for maximal binding of the PTK ZAP‐70. Quantitative binding experiments show that nanomolar concentrations of the doubly phosphorylated ζ1‐ITAM are sufficient for ZAP‐70 recruitment, whereas micromolar levels of singly phosphorylated ITAM are necessary for p59fyn binding. ZAP‐70 binds with low efficiency to a singly phosphorylated ITAM, but shows preferential binding to the C‐terminal phosphotyrosine in the ITAM, whereas p59fyn binds selectively to the N‐terminal phosphotyrosine. The present data thus show that there is the potential for a singly phosphorylated ITAM to couple to cellular PTK. Moreover, the data suggest a mechanism for heterogeneity in signal transduction responses by the TCR, since ITAM could differentially couple the TCR to downstream signaling events depending on their phosphorylation state.
CD30 ligation induces nuclear factor‐ϰB activation in human T cell lines
Authors: McDonald Patrick P. , Cassatella Marco A. , Bald Anette , Maggi Enrico , Romagnani Sergio , Gruss Hans‐Jürgen , Pizzolo Giovanni 
Published: March 2007

AbstractCD30 is a recently described member of the tumor necrosis factor/nerve growth factor receptor superfamily. In this report, we show that following incubation of L540 cells (Hodgkin's disease‐derived, T cell‐like, CD30+ cells) with the agonistic anti‐CD30 monoclonal antibodies (mAb) M44 and M67, two nuclear factor (NF)‐ϰB DNA binding activities were induced in nuclear extracts, as determined in gel retardation assays. The effect of the mAb towards NF‐ϰB activation was rapid, as it occurred within 20 min, and was sustained for up to 6h. By comparison, an isotype‐matched antibody had no effect on NF‐ϰB activation. Moreover, in human T helper (Th) clones functionally characterized as being of the type 0, type 1 and type 2 (28%, < 1% und 93% CD30+, respectively), the extent of CD30‐mediated NF‐ϰB activation correlated with the proportion of CD30+ cells. In all cell lines investigated, the NF‐ϰB complexes induced following CD30 engagement were shown to contain p50 NF‐ϰB1, p65 RelA, and possibly other transcription factors. Collectively, our results demonstrate that nuclear translocation and activation of NF‐ϰB rank among the short‐term cellular responses elicited following CD30 ligation.
Enhancement of endotoxin‐induced interleukin‐10 production by SR 31747A, a sigma ligand
Authors: Bourrie Bernard , Bouaboula Monsif , Benoit Jean‐Marc , Derocq Jean‐Marie , Esclangon Martine , Le Fur Gérard , Casellas Pierre 
Published: March 2007

AbstractSR 31747A is a new sigma ligand eliciting immunosuppressive and anti‐inflammatory properties. Here, we show that SR 31747A greatly enhances lipopolysaccharide (LPS)‐induced systemic release of interleukin (IL)‐10, while it inhibits the secretion of tumor necrosis factor (TNF)‐α and interferon (IFN)‐γ. In line with this finding, we also show by using quantitative reverse transcription‐polymerase chain reaction analysis that SR 31747A increased LPS‐induced IL‐10 mRNA accumulation in spleen cells, whereas the level of both TNF‐α and IFN‐γ mRNA was dramatically decreased. The enhancement of IL‐10 production by SR 31747A treatment was also apparent in nude and severe‐combined immunodeficient mice treated with LPS, clearly indicating that T and B cells were not involved. Finally, SR 31747A conferred protection against the lethal effect of LPS. The finding that SR 31747A strongly stimulates the synthesis of the natural anti‐inflammatory cytokine IL‐10, a property not observed with dexamethasone, provides new insights for the clinical use of this original compound, particularly in chronic inflammatory diseases where IL‐10 is believed to be a pivotal regulatory component.
NKG2‐C is a receptor on human natural killer cells that recognizes structures on K562 target cells
Authors: Düchler Markus , Offterdinger Martin , Holzmüller Harry , Lipp Joachim , Chu Chien‐Ts , Aschauer Barbara , Bach Fritz H. , Hofer Erhard 
Published: March 2007

AbstractNKG2‐C is a member of the recently discovered NKG2 family of genes and proteins, which are preferentially expressed on human natural killer (NK) cells. These potential NK cell receptors belong to a larger class of type II transmembrane proteins with a C‐type lectin domain. We show here that NKG2‐C is expressed as a 36‐kDa glycoprotein by translation in vitro, recombinant expression and immunoprecipitation from a human NK cell clone. Further, a recombinant soluble NKG2‐C‐receptor binds specifically to K562 cells, which are target cells for NK cell killing, and to RPMI 8866 cells, which are feeder cells for NK cells; several other hematopoietic cell lines tested do not show any binding. The binding structures on the surface of K562 cells disappear, concomitant with a loss in susceptibility to killing when the cells are induced to differentiate with phorbol ester and Ca2+ ionophore. Our data suggest the presence of specific target molecules for NKG2‐C on K562 cells, since overall glycosylation, Lewis X and Lewis Y structures, as well as the mucin‐like CD43 molecule, do not change following induction of the cells. We propose that NKG2‐C mediates a specific interaction of NK cells and their target cells with functional importance for NK cell killing.
Modulation of immunity to Borrelia burgdorferi by ultraviolet irradiation: Differential effect on Th1 and Th2 immune responses
Authors: Brown Eric L. , Rivas Jorge M. , Ullrich Stephen E. , Young Colin R. , Norris Steven J. , Kripke Margaret L. 
Published: March 2007

AbstractUltraviolet B (UVB) radiation suppresses the delayed‐type hypersensitivity (DTH) response to alloantigen by a mechanism involving interleukin (IL)‐10. It has been hypothesized, based on this result, that UV irradiation shifts the immune response from a Th1 to a Th2 response. We tested this hypothesis using Borrelia burgdorferi (Bb) as an antigen under conditions where both DTH and antibody responses could be assessed. Mice were irradiated with a single dose of UV and then immunized with Bb in complete Freund's adjuvant (CFA). DTH was assessed by footpad challenge. At various time points thereafter, mice were bled, and the serum antibodies to Bb were quantitiated. Only IgG1, IgG2a, and IgG2b were produced in response to Bb. The IgG2a and IgG2b antibody responses, as well as the DTH response to Bb, showed UV dose‐dependent reductions after UV irradiation. The primary IgG1 response to Bb was very low and was unaffected by UV irradiation; however, the IgG1 secondary response was elevated in UV‐irradiated mice. Injection of anti‐IL‐10 antibody into UV‐irradiated mice within 24 h after UV exposure restored the DTH response, as well as the IgG2a and IgG2b antibody responses. In addition, injecting recombinant murine IL‐10 mimicked some of the effects of UV radiation. Our results support the hypothesis that in vivo, UV irradiation down‐regulates Th1 immune responses, while leaving Th2 responses intact, and suggest that IL‐10 is an important mediator of this effect.
The proto‐oncogene Vav product is constitutively tyrosine‐phosphorylated in normal human immature T cells
Authors: Gouy Hélène , Debré Patrice , Bismuth Georges 
Published: March 2007

AbstractThe proto‐oncogene Vav product is markedly tyrosine‐phosphorylated after the recruitment of various receptors of cells of hematopoietic origin, including mature T cells. Recent studies on Vav‐deficient mice have clearly implicated the product of the proto‐oncogene Vav in intrathymic T cell development. Vav tyrosine phosphorylation is probably crucial to connect early tyrosine kinase(s) to downstream molecular events leading to cell division and maturation that occur in the thymus. We investigated the tyrosine phosphorylation of Vav in human thymocytes. Immunoblotting experiments demonstrate that, as in mature T cells, tyrosine phosphorylation of Vav is induced following thymocyte stimulation through the T cell receptor. The main observation, however, is that an important fraction of cellular Vav is constitutively tyrosine‐phosphorylated in freshly isolated cells. This phenomenon takes place apparently both in the CD4+CD8+ and the more mature CD4+CD8− and CD4−CD8+ thymocyte cell subsets. Co‐immunoprecipitation experiments showed, moreover, that a small amount of Vav is engaged in the multimolecular complex that includes elements of the T cell receptor and the T cell specific ZAP‐70 tyrosine kinase. Altogether, these data suggest that a critical pathway for T cell development in the human thymus likely involves the permanent activation of Vav in vivo.
Generalized autoimmune disease in interleukin‐2‐deficient mice is triggered by an uncontrolled activation and proliferation of CD4+ T cells
Authors: Sadlack Benjamin , Löhler Jürgen , Schorle Hubert , Klebb Gabriele , Haber Hildegard , Sickel Eckart , Noelle Randolph J. , Horak Ivan 
Published: March 2007

AbstractInterleukin‐2‐deficient mice (IL‐2−/−) crossed to a BALB/c genetic background develop a lymphoproliferative syndrome with severe hemolytic anemia and die within 5 weeks of age. The presence of autoantibodies of various specificities and inflammatory lesions in several organs are indicative of a generalized autoimmune disease. No alterations of the immune system were observed in 6‐day‐old animals, but 10‐day‐old mice already showed an increased proliferation and polyclonal activation of lymphocytes. The treatment of IL‐2−/− mice with anti‐gp39(CD40L) antibody prevented the disease and indicated that the appearance of activated CD4+ T cells (CD44high, CD69+) represents the first alteration of the immune system in IL‐2−/− mice. Collectively, our results suggest that an essential role of IL‐2 in vivo, which is not compensated by other cytokines, is the maintenance of self tolerance.
Preferential dependence of autoantibody production in murine lupus on CD86 costimulatory molecule
Authors: Nakajima Atsuo , Azuma Miyuki , Kodera Sanki , Nuriya Satoru , Terashi Akiro , Abe Masaaki , Hirose Sachiko , Shirai Toshikazu , Yagita Hideo , Okumura Ko 
Published: March 2007

AbstractBlockade of the interactions between CD28/CTLA‐4 and their ligands, CD80 (B7, B7.1)/CD86 (B70, B7.2), seems an attractive means to induce antigenspecific peripheral tolerance in organ transplantation and autoimmune disease. Recently, diversities between CD80 and CD86 in expression, regulation, and function have been reported in certain cell populations and murine experimental disease models. To investigate the possible differential role of CD80 and CD86 in the development of lupus, we treated lupus‐prone NZB/WF1 mice with specific monoclonal antibodies (mAb) against CD80, CD86, or both. The treatment with a combination of anti‐CD80 and CD86 mAb before the onset of lupus completely prevented autoantibody production and nephritis, and prolonged survival. Interestingly, we found that anti‐CD86 mAb alone, but not anti‐CD80 mAb, efficiently inhibited autoantibody production. Subclass study on IgG antidouble‐stranded (ds) DNA antibody revealed that the treatment with anti‐CD86 mAb almost completely inhibited both IgG1 and IgG2b, but not IgG2a production. The incomplete reduction of IgG2a anti‐dsDNA antibody by anti‐CD86 mAb was compensated by the addition of anti‐CD80 mAb. A significant reduction of mRNA for interleukin (IL)‐2, interferon‐γ, IL‐4 and IL‐6 was observed in mice treated with a combination of anti‐CD80 and CD86 mAb or anti‐CD86 mAb alone. Treatment with both mAb after the onset of lupus resulted in a significantly prolonged survival with reduction of autoantibody production. These results suggest that CD86 plays a more critical role in autoantibody production, and CD86, but not CD80, contributes to Th2‐mediated Ig production. However, the blockade of both CD80 and CD86 are required for preventing the development and progression of lupus.
Allo‐skin graft rejection, tumor rejection and natural killer activity in mice lacking p56lck
Authors: Wen Tao , Zhang Li , Kung Sam K. P. , Molina Thierry J. , Miller Richard G. , Mak Tak W. 
Published: March 2007

AbstractMice lacking the p56lck molecule (lck−/−) have a profound block in the maturation of thymocytes and a greatly reduced number of peripheral mature T cells. To analyze further the functions of the T cells developed in lck −/− mice in vivo, we evaluated the ability of lck−/− mice to reject allo‐skin grafts and methylcholanthrene (MCA)‐induced syngeneic fibrosarcoma, and also examined the biological activity of lck −/− natural killer (NK) cells. Mice lacking p56lck failed to reject skin grafts from either MHC‐disparate or minor‐histocompatibility‐different donors, even after they had been primed with donor spleen cells. They also failed to reject the MCA‐induced immunogenic syngeneic fibrosarcoma, MC57X. NK activity in mice lacking p56lck was normal, and there were no differences in the NK cell activation induced by poly(I) · poly(C) stimulation or interleukin‐2 stimulation (lymphokine‐activated killer induction) between mice lacking p56lck and their immunocompetent heterozygous littermates. NK cells lacking p56lck mediated a normal antibody‐dependent cell‐mediated cytotoxicity (ADCC) response. The results of this study indicate that the loss of p56lck severely impairs the effectors of the immune system which mediate the rejection of allo‐skin grafts and syngeneic tumors. The normal NK activity in lck −/− mice suggests that p56lck is not required for the development and activation of NK cells.
A sensitive assay for detecting low‐affinity interactions at the cell surface reveals no additional ligands for the adhesion pair rat CD2 and CD48
Authors: Brown Marion H. , Preston Sandy , Barclay A. Neil 
Published: March 2007

AbstractThe ligand for the T cell antigen CD2 is CD48 in rodents, but CD58 in humans. The extracelluar parts of these three antigens are structurally related in that all contain two immunoglobulin superfamily (IgSF) domains. There have been reports of alternative ligands for CD2 in the human, but not so far in rodents. We describe the analysis of ligands for rat CD2 and CD48 using fluorescent beads capable of displaying a high ligand density and detecting low‐affinity interactions like that of CD2 with CD48 (Kd = 60 − 90 μM). Monovalent chimeric proteins containing the two IgSF domains of rat CD48 or CD2 and domains 3 and 4 of rat CD4 (CD4d3+4) were anchored to fluorescent covaspheresTMvia a CD4 monoclonal antibody (mAb) with the CD48 or CD2 domains available for ligand binding. Multivalent CD48‐CD4d3 + 4 covaspheresTMgave strong specific binding to rat CD2 expressed on the surface of transfected Jurkat cells. CD48‐CD4d3+4 was compared with CD48‐IgG and CD48‐IgM as tools for detecting binding at the cell surface. Soluble divalent CD48‐IgG and decavalent CD48‐IgM bound to soluble CD2 with a Koffof around 10−3s−1as determined using a BIAcoreTMbiosensor. However, binding to cells by CD48‐IgG and CD48‐IgM was only detectable when they were immobilized on covaspheresTMand represented no increase in sensitivity over CD48‐CD4 covaspheresTMwhen tested for binding to cells expressing high and low levels of CD2. CD48‐CD4d3 + 4 covaspheresTMonly bound to rat cells expressing CD2. In the reverse orientation, binding of CD2‐CD4d3 + 4 covaspheresTMwas dependent on expression of CD48. Pre‐incubation of cells with CD2 or CD48 mAb abolished all binding of CD48‐CD4d3 + 4 or CD2‐CD4d3 + 4, respectively. The data provide no evidence for an alternative ligand for rat CD2 or CD48.
Role of tumor necrosis factor‐α in the regulation of activated synovial T cell growth: Downregulation of synovial T cells in rheumatoid arthritis patients
Authors: Lai Ning‐Sheng , Lan Joung‐Liang , Yu Chia‐Li , Lin Rong‐Hwa 
Published: March 2007

AbstractTo characterize the role of tumor necrosis factor (TNF)‐α in regulating synovial T cell growth, cell cycle progression associated with TNF‐α in mitogen‐activated synovial T cells of patients with rheumatoid arthritis (RA) were analyzed. After mitogen stimulation, the majority of synovial T cells in RA patients accumulated in S‐phase. Anti‐human TNF‐α monoclonal antibody and soluble recombinant human TNF receptor (rhTNFR) can block S‐phase accumulation. Furthermore, synovial fluid (SF) from RA patients was able to inhibit the proliferation of these S‐phase‐accumulated T cells. These data indicate that TNF‐α could regulate activated synovial T cell growth by driving them into S‐phase. Combined with the activities of other components of SF, TNF‐α seems to play an important role in down‐regulating activated synovial T cells in RA patients. In addition, the elevated level of soluble TNFR in the SF of disease‐active RA patients is believed to be associated with the promotion of synovial T cell responses.
A human follicular lymphoma B cell line hypermutates its functional immunoglobulin genes in vitro
Authors: Wu Hongyan , Pelkonen Eila , Knuutila Sakari , Kaartinen Matti 
Published: March 2007

AbstractThe functional immunoglobulin (Ig) genes of B lymphocytes undergo somatic mutations during immune responses. These mutations modify the antigen binding site of the immunoglobulins, thereby enhancing the average affinity of the antibodies produced. The molecular mechanism underlying these B cell hypermutations remains unresolved, partly because it is difficult to grow normal B cells in long‐term cell cultures and because there is no suitable transformed or malignant B cell line which generates mutations in its immunoglobulin genes in vitro. Here, we show that the recently established follicular lymphoma line HF‐1.3.4 generates somatic hypermutations in vitro at a high frequency of 0.7 × 10−6 mutations per base pair per generation in standard cell cultures (RPMI 1640 + 5% fetal calf serum). This shows for the first time that B cell hypermutation can occur without T cells or T cell factors. The mutation frequency increased approximately tenfold to 1 × 10−5 mutations/base pair/generation with B cell‐specific growth factors (interleukins −2 and −4 and three antibodies stimulatory to HF‐1.3.4 cells). This HF‐1.3.4 lymphoma line may help to elucidate the molecular mechanism of Ig gene hypermutation.
Mitochondrial perturbations define lymphocytes undergoing apoptotic depletion in vivo
Authors: Castedo Maria , Macho Antonio , Zamzami Naoufal , Hirsch Tamara , Marchetti Philippe , Uriel José , Kroemer Guido 
Published: March 2007

AbstractWe have recently shown that lymphocyte apoptosis induced by dexamethasone or superantigens is accompanied by reduction of mitochondrial transmembrane potential (ΔΨm) which precedes nuclear DNA fragmentation. Here, we demonstrate that fluorochromes such as 3,3′dihexyloxacarbocyanine iodide [DiOC6(3)] which measure ΔΨm, or fluorochromes such as hydroethidine (HE) which measure mitochondrial superoxide anion production allow the identification of thymocytes or peripheral T lymphocytes which are eliminated by apoptosis in vivo. In mice bearing transgenic α/β T cell receptor (TCR) specific for a class I‐restricted male‐specific peptide, the superoxide‐mediated oxidation of HE into ethidium (Eth) is enhanced among thymocytes which are being deleted due to negative selection (CD4+ CD8+ cells expressing the transgenic TCR in male mice) or lack of positive selection (CD4+ CD8− thymocytes from female mice). ΔΨm reduction and/or enhanced HE oxidation are also found when apoptosis is induced by a series of pathogenic agents. Thus, lethal irradiation provokes mitochondrial and nuclear signs of apoptosis, and both these alterations are absent in mice bearing a p53 null mutation, underlying the correlation between mitochondrial perturbation and nuclear apoptosis. Similarly, superantigen‐triggered deletion of peripheral T cells in vivo is accompanied by enhanced HE → Eth conversion and reduced DiOC6(3) uptake. More importantly, as compared to normal controls. CD4+ or CD8+ cells from clinically asymptomatic human immunodeficiency virus‐1 (HIV‐1) carriers also contain a significantly elevated percentage of cells endowed with reduced DiOC6(3) uptake. In superantigen‐ and HIV‐induced apoptosis, the percentage of T lymphocytes with a subnormal DiOC6(3) uptake is more important than that of cells marked by enhanced HE → Eth conversion. In conclusion, mitochondrial alterations precede and/or accompany nuclear signs of apoptosis induced by physiological and a variety of different pathogenic agents in vivo.
Altered Th1/Th2 balance associated with the immunosuppressive/protective effect of the H‐2Ab allele on the response to allo‐4‐hydroxyphenylpyruvate dioxygenase
Authors: Brunner Monika , Larsen Sanne , Sette Alessandro , Mitchison Avrion 
Published: March 2007

AbstractThe H‐2Ab allele exerts a dominant down‐regulatory effect on the anti‐allo‐HPPD (4‐hydroxyphenylpyruvate dioxygenase) antibody response, through a hitherto unknown mechanism. In the present study, the allo‐variable peptide bound to responder H‐2Ak molecules with higher affinity than to H‐2Ab ones, arguing against the operation of an affinity hierarchy. Quantitative polymerase chain reaction revealed differences in cytokine mRNA expression between suppressed and high‐responder mice. Lymph node cells of responder but not suppressed mice contained high levels of interleukin (IL)‐4 mRNA as early as 11 h post‐immunization and continued to do so for at least 8 days; this early burst was paralleled by a small burst in transforming growth factor (TGF)‐β mRNA level. Differences in IL‐12 mRNA were not detected, although an early IL‐12 effect could not be excluded. Interferon (IFN)‐γ appeared to contribute to the suppression at later time points. Early treatment of responder mice with anti‐IL‐4 monoclonal antibody (11B11) down‐regulated the antibody response. The proliferative T cell response from hyperimmunized mice was reduced but still detectable in the presence of an H‐2Ab allele. Thus, in the presence of this allele, the Th1 response is enhanced and that of Th2 cells suppressed, apparently as a result of the bias of H‐2Ab‐restricted T cells in favor of the Th1 subset.
Human T lymphocyte activation induces tyrosine phosphorylation of α‐tubulin and its association with the SH2 domain of the p59fyn protein tyrosine kinase
Authors: Marie‐Cardine Anne , Kirchgessner Henning , Eckerskorn Christoph , Meuer Stefan C. , Schraven Burkhart 
Published: March 2007

AbstractA glutathione‐S‐transferase‐src‐homology domain 2 (GST‐SH2) fusion protein was employed to identify molecules interacting with the protein tyrosine kinase p59fyn. Among several proteins which bound to the fyn SH2 domain in lysates of human Jurkat T lymphocytes, α‐ and β‐tubulin were identified by N‐terminal sequencing. Further analysis established that α‐tubulin exists as a tyrosine‐phosphorylated protein in Jurkat cells, where it interacts with p59fyn, but not with p56lck. By contrast, in untransformed resting human T lymphocytes α‐tubulin is not detectable as a tyrosine phosphorylated protein. However, following T cell activation, it becomes rapidly phosphorylated on tyrosine residues and subsequently associates with the SH2 domain of fyn. Interestingly, constitutively tyrosine‐phosphorylated α‐tubulin that is able to interact with the fyn‐SH2 domain is expressed in peripheral blood T lymphoblasts isolated from leukemic patients in the absence of external stimulation.