bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crossrecognition by CD8 T cell receptor αβ cytotoxic T lymphocytes of peptides in the self and the mycobacterial hsp60 which share intermediate sequence homology
Authors: Zügel Ulrich , Schoel Bernd , Yamamoto Shigeki , Hengel Hartmut , Morein Bror , Kaufmann Stefan H. E. 
Published: March 2007

AbstractImmunization of C57BL/6 mice with the mycobacterial heat shock protein (hsp) 60 in immunostimulating complexes caused the in vivo activation of autoreactive major histocompatibility complex class I (H‐2Db)‐restricted CD8 T cell receptor (TcR) α/β cells. A CD8 TcR α/β clone with specificity for the mycobacterial hsp60 peptide499–508 was derived from this immunization, which, in addition, recognized syngeneic macrophages which had been stressed by interferon‐γ (IFN‐γ) stimulation. The stress‐induced, self peptide could be extracted from IFN‐γ‐stressed macrophages by acid elution, suggesting that the IFN‐γ‐induced self peptide is derived from an endogenous protein. Based on our observation that lysis of stressed target cells by this cytotoxic T lymphocyte (CTL) clone was specifically inhibited by hsp60‐specific antisense oligonucleotides, we used synthetic peptides representing amino acid (aa) sequences of the murine hsp60 for target cell sensitization and identification of the relevant self peptide. Synthetic peptides representing 9‐mer to 11‐mer aa sequences of the murine hsp60 with asparagine in anchor position 4 or 5 as the minimal requirement for H‐2Db binding were tested in CTL assays. The overlapping murine hsp60 peptides162–170/171 were stimulatory at a concentration as low as 10–100 pM. Seven other peptides of the murine hsp60 required intermediate peptide concentrations of 10–100 nM for recognition by the CTL clone. Although the murine and mycobacterial hsp60 peptides recognized by this CTL clone showed only intermediate homology (3 identical and 3 similar aa), our data suggest that endogenous hsp60 itself is the source of self peptide(s) presented by IFN‐γ‐stressed macrophages to the cross‐reactive CTL clone with promiscuous specificity. This notion is consistent with the idea of hsp as a link between infection and autoimmunity.
Phosphatidylinositol 3‐kinase activity is not essential for CD28 costimulatory activity in Jurkat T cells: studies with a selective inhibitor, wortmannin
Authors: Lu Yiling , Phillips Catherine A. , Trevillyan James M. 
Published: March 2007

AbstractThe interaction of CD28 with its counter‐receptor, B7‐1 (CD 80), on antigenpresenting cells induces a co‐signal in T cells required to promote antigendependent interleukin‐2 (IL‐2) production and to prevent clonal anergy. CD28 stimulation causes both protein‐tyrosine kinase and phosphatidylinositol3‐kinase (PI3‐K) activation, suggesting a possible role for these enzyme activities in CD28 co‐signal transduction. Here, we investigate the effect of wortmannin, a selective and irreversible PI3‐K inhibitor on CD28 co‐signaling events in the Jurkat T cell line. Wortmannin added to cell cultures partially inhibits CD28‐induced tyrosine phosphorylation of the putative p110 catalytic subunit of PI3‐K, but does not block CD28‐induced association of the p85 PI3‐K regulatory subunit with the CD28 receptor. Wortmannin inhibits in a dose‐dependent manner both total cellular PI3‐K activity and CD28‐induced receptor‐associated PI3‐K activity. Wortmannin (1 μM) inhibits cellular PI3‐K activity by 90% with complete inhibition achieved at 10 μM. The inhibitory effect of wortmannin on cellular PI3‐K activity is prolonged (> 18 h), suggesting that the drug is not readily metabolized by Jurkat T cells. Wortmannin, at concentrations that blocked PI3‐K activity, fails to inhibit the synergistic effect of CD28 on IL‐2 secretion in the presence of phorbol 12‐myristate 13‐acetate and ionomycin. These data demonstrate that CD28‐induced signaling events other than the activation of PI3‐K catalytic activity contribute to the control of IL‐2 secretion.
FK506 binding protein 12 mediates sensitivity to both FK506 and rapamycin in murine mast cells
Authors: Fruman David A. , Wood Michael A. , Gjertson Carl K. , Katz Howard R. , Burakoff Steven J. , Bierer Barbara E. 
Published: March 2007

AbstractThe immunosuppressive drugs FK506 and rapamycin bind to a family of intracellular proteins termed FK506‐binding proteins (FKBP). FK506 and rapamycin inhibit lymphocyte‐activation pathways by forming complexes with an FKBP; subsequently, the drug/FKBP complexes interact with target molecules involved in signal transduction. A key target of FK506/FKBP12 complexes is calcineurin, a calcium‐ and calmodulin‐dependent serine/threonine phosphatase. In mammalian cells, rapamycin treatment is associated with inhibition of the activity of several cellular serine/threonine kinases, including p70 S6 kinase. These kinases may function in signaling pathways involving TOR gene producs, which have been shown to interact with rapamycin/FKBP12 complexess in vitro. To determine if FKBP12 mediates the effects of both FK506 and rapamycin in mammalian cells, we overexpressed FKBP12 in a murine mast cell line. Increased expression of FKBP12 resulted in increased sensitivity to FK506 and rapamycin, as measured by inhibition of calcineurin activity and p70 S6 kinase activity, respectively. In contrast, overexpression of FKBP25 had no effect on sensitivity to either drug. Two distinct point mutations in FKBP12, one altering a hydrophobic residue within the drug‐binding pocket and the other changing a charged surface residue of FKBP12, abrogated its ability to mediate sensitivity to FK506 and rapamycin. These results establish that FKBP12 can mediate sensitivity to both FK506 and rapamycin in mammalian cells.
The third component of Xenopus complement: cDNA cloning, structural and functional analysis, and evidence for an alternate C3 transcript
Authors: Lambris John D. , Pappas John , Mavroidis Manolis , Wang Yang , Manzone Holly , Swager Joseph , Pasquier Louis Du , Silibovsky Randi 
Published: March 2007

AbstractAlthough the third component of complement has been purified from two amphibian species, Xenopus laevis and the axolotl, only limited information is available about its primary structure in these species. We now present (a) 95% of the cDNA sequence encoding C3 from a Xenopus laevis/Xenopus gilli (Xenopus LG) hybrid (b) an analysis of the C3 convertase and factor I cleavage sites in Xenopus C3, and (c) evidence for an alternative form of C3. The Xenopus LG sequence has a 57% nucleotide and 52% amino acid sequence identity to human C3 and contains one potential N‐glycosylation site in the β‐chain. The deduced amino acid sequence showed that the C3 convertase and factor I cleavage sites (Arg‐Ser) are conserved in Xenopus C3 and protein sequencing of Xenopus C3 fragments fixed on zymosan during complement activation demonstrated that Xenopus C3 is indeed cleaved by C3 convertase and factor I at these sites. Our screening of a liver cDNA library identified an unusual C3 clone with a deletion of 2502 bp, suggesting the presence of a novel C3 transcript in Xenopus LG liver. The presence of this C3 transcript was confirmed by reverse transcription polymerase chain reaction using Xenopus LG liver mRNA and specific oligonucleotide probes. This transcript encoded a putative 102‐kDa protein comprising the β‐chain of C3, together with the first 59 residues and the last 103 residues of the α‐chain; it would therefore lack many of the ligand binding sites found in the intact <α‐chain. However, the molecule may be an analog of a truncated C3 molecule that is found in the serum of allergic dermatitis patients and acts as an inhibitor of eosinophil cytotoxicity and neutrophil adherence.
Induction in vitro of a primary human antiviral cytotoxic T cell response
Authors: Cerny Andreas , Fowler Patricia , Brothers Mary A. , Houghton Michael , Schlicht Hans J. , Chisari Francis V. 
Published: March 2007

AbstractWe report herein the successful priming of human anti‐viral cytotoxic T cells (CTL) in vitro using two induction strategies based on the stimulation of peripheral blood mononuclear cells isolated from uninfected donors with synthetic viral peptides. The peptides used contain HLA‐A2 binding motifs and have been identified as HLA‐A2‐restricted CTL epitopes in patients infected by the hepatitis B and C viruses. One approach uses repetitive long‐term stimulation and the other uses bulk cultures containing large numbers of naive peripheral blood mononuclear cells. Both approaches successfully induce HLA‐A2‐restricted CTL specific for several viral epitopes. Some CTL recognize endogenously synthesized antigen on target cells infected with recombinant vaccinia virus expressing the corresponding viral proteins. This simple technique permits easy analysis of the primary human CTL repertoire, and may be exploitable for production of specific CTL effector cells for adoptive immunotherapy and dissection of the cellular and molecular requirements for priming of naive human CTL.
Secondary rearrangements and post‐rearrangement selection contribute to restricted immunoglobulin DJH expression in young rabbit bone marrow
Authors: Fitts Matthew G. , Mage Rose G. 
Published: March 2007

AbstractExtrachromosomal circular DNA purified from bone marrow cells of 2‐weeks‐old rabbits was assayed by polymerase chain reaction to determine the relative rearrangement frequencies of immunglobulin DH to JH genes in vivo. DH genes rearranged to individual JH genes with different frequencies. This bias did not correlate with potential sequence overlaps in the DH or JH coding sequences. The JH2 and JH4 genes were the preferred targets of recombination in primary rearrangements. Although primary rearrangements to JH6 were relatively infrequent, secondary rearrangements were detected. This assay also revealed previously undescribed JH pseudogenes with functional recombination signal sequences. Analyses of genomic VDJH indicated that B cells expressing VDJH4 heavy chains survived and dominated in the bone marrow environment due to secondary rearrangements and/or post‐rearrangement selection.
The role of the B cells in the adoptive transfer of collagen‐induced arthritis from DBA/1 (H‐2q) to SCID (H−2d) mice
Authors: Taylor Peter Charles , Plater‐Zyberk Christine , Maini Ravinder Nath 
Published: March 2007

AbstractCollagen‐induced arthritis (CIA) can be transferred from DBA/1 to SCID mice when native type II collagen (CII) is administered together with spleen cells, arthritis appearing some 14 days after cell transfer. In the present study, we demonstrate that both donor T‐ and B‐lymphocyte populations play a role in this model, and that arthritis arises in SCID recipients of either murine or bovine native CII. Furthermore, the requirement for administration of soluble native CII can be replaced by subarthritogenic doses of serum from Wistar rats with CIA. In this case a fully developed arthritis appears as early as 2 days after cell transfer. However, protein G‐purified IgG from CIA rat serum together with splenocytes from arthritic DBA/1 mice does not transfer arthritis.A key role of B cells in this model appears to be the production of a humoral arthritogenic factor since arthritis can be successfully transferred to SCID mice by CIA rat serum administered together with a B cell‐depleted splenocyte population consisting of T cells and donor‐histocompatible antigen‐presenting cells. By contrast, transfer of disease cannot be achieved by co‐administration of CIA rat serum and purified donor T cells, indicating that the presence of donor antigen‐presenting cells is a requirement for adoptive transfer of arthritis.We propose that joint damage initiated by arthritogenic product(s) of the B cell lineage releases soluble antigens that are presented to T cells which perpetuate the disease. The finding that arthritis can be generated in SCID recipients of CIA rat serum together with splenocytes from non‐arthritic DBA/1 mice immunized with denatured CII supports the hypothesis that T cells with specificity for denatured joint components perpetuate disease initiated by humoral factors.
B lymphocyte recognition of cytochrome c: higher frequency of cells specific for self versus foreign antigen early in the immune response and V gene usage in the response to self antigen
Authors: Minnerath Jeanne M. , Mueller Carolyn M. , Buron Susan , Jemmerson Ronald 
Published: March 2007

AbstractTo study immunoglobulin gene usage in the antibody response of mice to the self antigen (Ag) mouse cytochrome c (cyt), B cell hybridomas were prepared from splenic B cells of immunized BALB/c mice prior to the onset of somatic mutation, i.e. 3 days after injecting ovalbumin (OVA)‐primed mice with mouse cyt coupled to OVA. Monoclonal antibodies (mAb) from all of the seven primary hybridomas we obtained were sensitive to a single amino acid substitution from aspartic acid to glutamic acid at position 62 in mouse cyt. This is the specificity of the vast majority of B cells responding to mouse cyt as determined from assays of B cells activated in splenic fragment cultures. Six of the mAb derive from the 19.1.2 J558 VH gene which is also used in the response to α (1 → 6) dextran and three of these mAb derive from the R9 Vx gene, a member of the VxOx‐1 family. The other mAb derive from distinct, although similar, Vx genes. Attempts to obtain hybridomas secreting primary (unmutated) mAb specific for cyt foreign to mice have been hampered by the much lower frequency of B cells responding early to foreign cyt in comparison to the self Ag. This suggests that, contrary to expectation of tolerance mechanisms, in naive BALB/c mice B lymphocytes specific for a single epitope on self cyt are present in higher frequency than B lymphocytes specific for similar epitopes on foreign cyt. Possible explanations for this result include biased expression in the B cell repertoire of the particular combination of V genes encoding mouse cyt‐specific mAb or to positive selection of developing B lymphocytes by endogenous Ag.
T cell receptor Vβ repertoire in mice lacking endogenous mouse mammary tumor provirus
Authors: Braun Michel Y. , Jouvin‐Marche Evelyne , Marche Patrice N. , MacDonald H. Robson , Acha‐Orbea Hans 
Published: March 2007

AbstractWhen endogenous mouse mammary tumor virus (MMTV) superantigens (SAg) are expressed in the first weeks of life an efficient thymic deletion of T cells expressing MMTV SAg‐reactive T cell receptor (TcR) Vβ segments is observed. As most inbred mouse strains and wild mice contain integrated MMTV DNA, knowing the precise extent of MMTV influence on T cell development is required in order to study T cell immunobiology in the mouse. In this report, backcross breeding between BALB.D2 (Mtv‐6, −7, −8 and −9) and 38CH (Mtv−) mice was carried out to obtain animals either lacking endogenous MMTV or containing a single MMTV locus, i.e. Mtv‐6, −7, −8 or −9. The TcR Vβ chain (TcR Vβ) usage in these mice was analyzed using monoclonal antibodies specific for TcR Vβ2,Vβ3, Vβ4,β5,Vβ6,Vβ7,Vβ8,Vβ11,Vβ12 and Vβ14 segments. Both Mtv‐8+ mice and Mtv‐9+ mice deleted TcR Vβ5+ and Vβ11+ T cells. Moreover, we also observed the deletion of TcR Vβ12+ cells by Mtv‐8 and Mtv‐9 products. Mtv‐6+ and Mtv‐7+ animals deleted TcR Vβ3+ and Vβ35+ cells, and TcR Vβ6+,Vβ7+ and Vβ8.1+ cells, respectively. Unexpectedly, TcR Vβ8.2+ cells were also deleted in some backcross mice expressing Mtv‐7. TcR Vβ8.2 reactivity to Mtv‐7 was shown to be brought by the 38CH strain and to result from an amino acid substitution (Asn → Asp) in position 19 on the TcR Vβ8.2 fragment. Reactivities of BALB.D2 TcR Vβ8.2 and 38CH TcR Vβ8.2 to the exogenous infectious viruses, MMTV(SW) and MMTV(SHN), were compared.Finally, the observation of increased frequencies of TcR Vβ2+, Vβ4+ and Vβ8+ CD4+ T cell subsets in Mtv‐8+ and Mtv‐9+ mice, and TcR Vβ4+ CD4+ T cells in Mtv‐6+ and Mtv‐7+ mice, when compared with the T cell repertoire of Mtv− mice, is consistent with the possibility that MMTV products contribute to positive selection of T cells.
Effects of interleukin (IL)‐13 on immediate‐early response gene expression, phenotype and differentiation of human mast cells. Comparison with IL‐4
Authors: Nilsson Gunnar , Nilsson Kenneth 
Published: March 2007

AbstractThe recently cloned interleukin 13 (IL‐13) shares most investigated biological activities on B lymphocytes and monocytes with IL‐4. In this study we investigated the potential role of IL‐13 in regulating human mast cell activities. The effects of IL‐13 on the expression of an immediate‐early response gene (c‐fos), proliferation, expression of mast cell‐associated cell surface antigen (CD54 and Kit), and in vitro differentiation of human mast cells, were investigated. We compared the effect of IL‐13 with that of IL‐4. Both IL‐13 and IL‐4 induced expression of c‐fos in cells from the human mast cell line HMC‐1. This indicates that mast cells express functional receptors for IL‐13. IL‐13 and IL‐4 decreased the proliferation rate of HMC‐1 cells. However, IL‐13 was less potent than IL‐4. Human mast cells constitutively express the adhesion molecule ICAM‐1 (CD54) and the receptor for stem cell factor (Kit) (CD117). The expression of CD54 was increased after treatment with IL‐13 or IL‐4, whereas the expression of Kit was decreased. Also in this action IL‐4 was more potent than IL‐13. By culturing mononuclear cells from cord blood in the presence of stem cell factor there is a differentiation of tryptase‐positive mast cells in the cultures. This process was inhibited when IL‐4 was present. In contrast, IL‐13 did not affect the expression of tryptase during differentiation of stem cell factor dependent cord blood‐derived mast cells. Taken together, these findings indicate that IL‐13 has regulatory effects on human mast cells. The effect overlaps with but is also different from that of IL‐4.
Simple strategy to induce antibodies of distinct specificity: Application to the mapping of gp120 and inhibition of HIV‐1 infectivity
Authors: Prieto Isidro , Hervás‐Stubbs Sandra , García‐Granero Marta , Berasain Carmen , Riezu‐Boj José‐Ignacio , Lasarte Juan‐José , Sarobe Pablo , Prieto Jesus , Borrás‐Cuesta Francisco 
Published: March 2007

AbstractIn this study 96 15‐mer peptides encompassing the entire sequence of HIV‐1 gp120 were synthesized and used to immunize BALB/c mice (i) alone or (ii) in conjunction with the T helper cell determinant FISEAIIHVLHSR (FIS) from sperm whale myoglobin, which is well recognized by major histocompatibility complex (MHC) class II molecules of BALB/c. Of these peptides 39 were immunogenic per se and 57 were not. Out of the 57 non‐immunogenic peptides 53 could be rendered immunogenic with the second immunization protocol. With the exception of 4 cases, the anti‐peptide antibody titers induced in (ii) were equal (14 cases) or higher (78 cases) than those induced in (i). From the 96 anti‐peptide antibodies tested, 12 were able to recognize recombinant gp120 with good antibody titers, a result in agreement with previously identified B cell epitopes from gp120 by anti‐peptide antibodies induced with longer peptides conjugated to a carrier protein. Moreover, 4 of the 12 anti‐peptide antisera that recognized gp 120 were able to neutralize HIV‐1 infectivity in vitro, showing that the strategy of co‐immunization with FIS may afford functional antibodies.
T cells expressing the γδ T cell receptor are not required for egg granuloma formation in schistosomiasis
Authors: Iacomini John , Ricklan David E. , Stadecker Miguel J. 
Published: March 2007

AbstractImmunopathology in schistosomiasis consists of a granulomatous response around parasite eggs. It has been established that granuloma formation is mediated by CD4+ T helper cells. However, the role of T cells bearing the γδ T cell receptor (TCR) has not been determined. In this study we utilized mutant mice that lack either αβ or γδ T cells as a result of gene targeting to investigate the relative roles of αβ and γδ T cells in the induction of immunopathology related to schistosomiasis. Mutant and control mice were infected with Schistosoma mansoni and granuloma formation as well as lymph node cell proliferative responses to egg antigens were analyzed after 8 weeks. TCR δ mutant mice (lacking γδ T cells) displayed vigorous formation of egg granulomas that were not significantly different from those observed in normal controls, both in terms of granuloma size and cellular composition. In contrast, TCR α and TCR β mutant mice (lacking αβ T cells) were unable to form granulomas. Moreover, mesenteric lymph node cells from TCR δ mutant and control mice responded strongly to egg antigens in vitro, while TCR α and β mutant mice did not. Our studies show that in schistosomiasis granuloma formation and proliferative responses to egg antigens are strictly dependent on αβ T cells. They also suggest that γδ T cells by themselves can neither mediate a granulomatous inflammation, nor significantly modify one mediated by αβ T cells.
Regulation of interferon‐γ mRNA in a cytolytic T cell clone: Ca2+‐induced transcription followed by mRNA stabilization through activation of protein kinase C or increase in cAMP
Authors: Kaldy Pierre , Schmitt‐Verhulst Anne‐Marie 
Published: March 2007

AbstractActivation pathways inducing the expression of the interferon (IFN)‐γ gene in a cytotoxic T lymphocyte (CTL) clone were studied for their effects on transcription and on mRNA stability. IFN‐γ was secreted by the CTL clone in response to the Ca2+ ionophore ionomycin when used in conjunction with either protein kinase C (PKC)‐activating phorbol 12‐myristate 13‐acetate (PMA) or with agents increasing cAMP, including prostaglandin E2. We describe that ionomycin induced IFN‐γ gene transcription, which was totally inhibited in the presence of cyclosporin A (CSA), an immunosuppressant forming a calcineurin‐inhibiting complex with cyclophilin. Ionomycin did not, however, permit accumulation of IFN‐γ mRNA. Activation of PKC by PMA or of cAMP‐dependent protein kinase through increase in cAMP had no transcription‐inducing effect, either alone or in conjunction with ionomycin, as measured in run on assays of the IFN‐γ gene. When transcription of the IFN‐γ gene, initiated in the presence of ionomycin and an agent increasing intracellular cAMP, was inhibited by CSA in the absence of PKC or cAMP‐dependent protein kinase activation, the IFN‐γ mRNA was rapidly degraded (half‐life = 30 min). When either PKC was activated or intracellular cAMP was increased at the time of inhibition with CSA, a stabilizing effect was observed on IFN‐γ mRNA, which led to an increase in secreted IFN‐γ. These effects were selective, they did not affect the rate of transcription of the actin gene, nor the accumulation of actin mRNA.These results show that (i) post‐transcriptional events can be critical for IFN‐γ expression in activated lymphocytes, and (ii) specific stabilization of IFN‐γ mRNA can be mediated by activation of two different protein kinases involved in T cell activation.