bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic requirements for acceleration of diabetes in non‐obese diabetic mice expressing interleukin‐2 in islet β‐cells
Authors: Allison Janette , McClive Peter , Oxbrow Leonie , Baxter Alan , Morahan Grant , Miller Jacques F. A. P. 
Published: March 2007

AbstractDiabetes was dramatically accelerated in non‐obese diabetic (NOD) transgenic mice that expressed interleukin‐2 (IL‐2) in their β cells. A single cross to C57BL/6 completely prevented this effect and a further backcross to the NOD genetic background showed that at least two diabetes susceptibility loci (Idd1s and Idd3/10s) were required for the diabetes acceleration. T cells activated to islet antigens were not circulating in the mice. The accelerating effect of IL‐2 was present, but decreased, in NOD mice that lacked CD8+ T cells as well as in NOD SCID mice. The implications are that in the NOD genetic background, the production of cytokines, such as IL‐2, by islet‐specific CD4+ T cells can lead to β cell damage and diabetes and that CD8+ T cells may have a role in accelerating diabetes onset.
Staurosporine restores signaling and inhibits interleukin‐8‐induced chemotactic desensitization
Authors: Johnston James A. , Ferris Douglas K. , Wang Ji Ming , Longo Dan L. , Oppenheim Joost J. , Kelvin David J. 
Published: March 2007

AbstractInterleukin 8 (IL‐8) is a chemotactic cytokine (chemokine) that plays a key role in the accumulation and activation of neutrophils at inflammatory sites. In this report we demonstrate that homologous chemotactic desensitization occurs upon pretreatment of neutrophils with IL‐8 or N‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP) and results in the inhibition of neutrophil chemotaxis upon subsequent challenge with the same ligand. This homologous chemotactic desensitization could be prevented by pretreating the neutrophils with the protein kinase inhibitor staurosporine, indicating that protein kinases may play an essential role. The attenuation of homologous desensitization by staurosporine restored chemotaxis but was not associated with a change in IL‐8 receptor expression, affinity or the rate of ligand internalization, indicating that homologous desensitization does not alter ligand‐receptor interaction.Using two‐dimensional analysis we have shown that IL‐8 induced a rapid serine/threonine phosphorylation of a number of neutrophil substrates the most prominent being phosphoprotein 39 (pp39), extracellular signal‐related kinase‐1, pp55 and pp66. Prior desensitization of neutrophils with IL‐8 blocked all subsequent phosphorylation upon rechallenge with IL‐8. However, the desensitization was specific for IL‐8 since normal phosphorylation of identical substrates was observed in response to FMLP. When neutrophils were pretreated with staurosporine, prior to desensitization, phosphorylation of pp39 was observed upon restimulation with IL‐8. Further study revealed that pp55 and pp66 were not phosphorylated in the presence of staurosporine.Thus, homologous desensitization of neutrophils in response to IL‐8 does not result from changes in receptor expression, but rather from a staurosporine‐sensitive inactivation of subsequent signal transduction. This desensitization is selective since the cells are able to respond to other ligands.
In vitro priming of cytotoxic T lymphocytes against poorly immunogenic epitopes by engineered antigen‐presenting cells
Authors: Bellone Matteo , Iezzi Giandomenica , Manfredi Angelo A. , Protti Maria Pia , Dellabona Paolo , Casorati Giulia , Rugarli Claudio 
Published: March 2007

AbstractCytotoxic T lymphocytes (CTL) recognize antigenic peptides presented by major histocompatibility complex class I (MHC‐I) molecules on the surface of target cells. Optimal induction of CD8+ CTL depends on the amount of relevant peptide/MHC‐I complexes and the presence of co‐stimulatory molecules on antigen‐presenting cells (APC). The antigen‐processing defective mutant cell line RMA‐S, when cultured at low temperature, expresses high amounts of MHC‐I molecules that do not contain endogenously derived peptides. These “empty” MHC‐I molecules can be stabilized by addition of MHC‐binding peptides. RMA‐S cultured at low temperatures with selected peptides have been used for in vitro CTL induction with conflicting results. RMA‐S cells do not express detectable amounts of B7 co‐stimulatory molecule. This could explain their unpredictable efficiency as APC. We have evaluated whether RMA‐S cells, stably transfected with cDNA encoding for the human B7.1 molecule could provide effective co‐stimulation for CD8+ T lymphocytes. RMA‐S/B7 cells, loaded with different synthetic peptides, demonstrated a high and sometimes unique efficiency for in vitro primary CTL induction, even when “sub‐optimal” antigen peptides were used. Most importantly, RMA‐S/B7 cells pulsed with naturally processed peptides extracted from the poorly immunogenic B16 melanoma cells were able to prime CD8+ cells against B16 melanoma. We conclude that the use of RMA‐S/B7 cells as APC represents an ideal strategy for in vitro CTL immunization without prior in vivo priming. This system may also help to address the issue of the different contributions of co‐stimulation and relative occupancy of MHC‐I by single peptide epitopes in CTL priming.
Different kinetic patterns of cytokine gene expression in vivo in orally tolerant mice
Authors: Fishman‐Lobell Jacqueline , Friedman Aharon , Weiner Howard L. 
Published: March 2007

AbstractA biologically relevant mechanism of generating peripheral tolerance in T cells that have escaped thymic deletion is by the oral administration of soluble antigens. Oral tolerance occurs by two distinct mechanisms. Feeding a single high dose of antigen induces anergy of antigen‐specific TH1 cells, while multiple low doses of antigen induce regulatory Tcells that mediate suppression by producing immunosuppressive cytokines. Although cytokine production in orally tolerant animals has been well studied utilizing in vitro assay systems, semi‐quantitative characterization of cytokine production in oral tolerance in vivo has not been carried out. In this paper we have developed a system using semi‐quantitative RNA polymerase chain reaction to characterize cytokine gene expression in vivo in mice orally tolerized by feeding either a single high dose or multiple low dosages of antigen. We find that measurable differences in interleukin‐4 (IL‐4) and interferon‐γ (IFN‐γ) gene expression occurred between the tolerized and non‐tolerized groups. Qualitatively, IL‐4 mRNA was increased in both orally tolerized groups. However, significant differences in IL‐4 gene expression between the two groups in both magnitude and kinetics were found. A large but short‐lived increase in IL‐4 was produced in mice fed a single high dose, while a relatively more moderate, longer‐lived increase was produced in mice fed multiple low doses. The increase in IL‐4 gene expression was specific only to the draining lymph node following antigen administration. Expression of IFN‐γ was decreased in both orally tolerant groups. These results indicate that tolerance in TH1 cells is induced by both of these feeding regimens while TH2 responses are intact and amplified upon reexposure to antigen.
Localization of two cytotoxic T lymphocyte epitopes and three anchoring residues on a single nonameric peptide that binds to H‐2Ld and is recognized by cytotoxic T lymphocytes against mouse tumor P815
Authors: Van den Eynde Benoǐt , Mazarguil Honoré , Lethé Bernard , Laval Françoise , Gairin Jean Edouard 
Published: March 2007

AbstractMouse mastocytoma P815 expresses tumor antigens P815A and P815B encoded by a single gene called P1A and carried by a single peptide named P1A 35–43 (NH2‐Leu‐Pro‐Tyr‐Leu‐Gly‐Trp‐Leu‐Val‐Phe‐COOH). P1A 35–43 is presented to anti‐P815A and anti‐P815B cytotoxic T lymphocytes (CTL) by major histo‐compatibility complex (MHC) H‐2Ld molecules. In order to determine the individual role played by each amino acid residue of P1A 35‐43 in binding to H‐2Ld and in recognition by anti‐A and anti‐B T cell receptors (TcR), a series of P1A 35‐43 peptides substituted by alanine at single positions was synthesized and tested for binding to H‐2Ld and for CTL recognition. Binding to H‐2Ld was estimated by measuring the ability of the peptide to up‐regulate cell surface expression of H‐2Ld. We found that three residues were important for interaction of P1A 35‐43 with H‐2Ld. Two of them, Pro at position 2 and Phe at position 9 were consistent with the described H‐2Ld binding motif. A third residue, Trp at position 6, was also required for effective MHC binding of the tumor antigen. CTL sensitization assays showed that alanine substitution at position 7 (Leu) or at position 8 (Val) dramatically affected peptide recognition by anti‐A CTL while positions 3 (Tyr) and 4 (Leu) were critical for recognition by anti‐B CTL. We conclude that Pro2, Trp6 and Phe9 constitute the anchor residues of P1A 35‐43 to H‐2Ld, whereas the dipeptidyl sequences Tyr3‐Leu4 and Leu7‐Val8 form the core epitopes recognized by the TcR of anti‐P815B and anti‐P815A CTL, respectively.
The expansion of a CD4+ T cell population bearing a distinctive β chain in MRL lpr/lpr mice suggests a role for the fas protein in peripheral T cell selection
Authors: Musette Philippe , Pannetier Christophe , Gachelin Gabriel , Kourilsky Philippe 
Published: March 2007

AbstractMRL lpr/lpr mice suffer from a systemic lupus erythematosus‐like autoimmune disease. The lpr mutation impairs the normal transcription of the fas message, the product of which mediates apoptosis and presumably the proper selection of T cells. We have found an early expansion of CD4+ T cells bearing a distinctive Vβ8.3‐Dβ1.1‐Jβ1.1 T cell receptor β chain in the periphery of MRL lpr/lpr mice, which was not detected in MRL +/+ mice nor in the thymus of MRL lpr/lpr mice. Thus, since thymic selection is normal in MRL lpr/lpr mice, we propose that the lpr mutation results in defective negative selection at the periphery.
Expression of E‐cadherin by murine dendritic cells: E‐cadherin as a dendritic cell differentiation antigen characteristic of epidermal Langerhans cells and related cells
Authors: Borkowski Teresa A. , Van Dyke Byron J. , Schwarzenberger Kathryn , McFarland Vivian W. , Farr Andrew G. , Udey Mark C. 
Published: March 2007

AbstractMurine epidermal Langerhans cells (LC) synthesize and express E‐cadherin, a homophilic adhesion molecule that mediates adhesion of LC to keratinocytes in vitro. To determine if E‐cadherin expression is characteristic of LC or is a feature of all dendritic cells (DC), we studied DC from various lymphoid tissues and peripheral blood for reactivity with anti‐E‐cadherin monoclonal antibody. By flow cytometry, DC prepared from skin‐associated lymph nodes (LN) expressed E‐cadherin, whereas DC prepared from gut‐associated LN and spleen did not. However, direct comparison revealed that levels of E‐cadherin expressed by DC from skin‐associated LN were ∼fivefold lower than those expressed by freshly‐prepared LC. Immunohistochemical studies confirmed that E‐cadherin was expressed by DC in skin‐associated LN in situ, and demonstrated that the number of E‐cadherin+ DC in LN draining skin previously treated with the contact allergen 2,4,6‐trinitrochlorobenzene was increased relative to the number of E‐cadherin+ DC present in LN draining normal skin. DC propagated from the blood of cyclophosphamide‐treated mice in granulocyte/macrophage‐colony stimulating factor‐supplemented media also expressed E‐cadherin. E‐cadherin immunoprecipitated from DC co‐migrated in SDS polyacrylamide gels with that from fibroblasts transfected with murine E‐cadherin cDNA, and mRNA encoding extracellular and intracellular regions of E‐cadherin was present in DC propagated from blood. These results indicate that E‐cadherin expressed by murine dendritic cells is identical to E‐cadherin expressed by epithelial cells, and suggest that E‐cadherin represents a DC differentiation antigen characteristic of LC and lineage‐related cells (skin‐associated LN DC).
Deficient expression of co‐stimulatory molecules on Leishmania‐infected macrophages
Authors: Kaye Paul M. , Rogers Nicola J. , Curry Allison J. , Scott Julia C. 
Published: March 2007

AbstractCo‐stimulatory signals are necessary for the full activation of T cells for growth and effector function. As co‐stimulatory molecules are normally regulated in their expression, it has been suggested that microorganisms enhance their expression on host antigen‐presenting cells (APC), thus allowing efficient generation of anti‐microbial immunity. We here describe experiments which demonstrate that infection of macrophages, both in vitro and in vivo, by the protozoan parasite Leishmania donovani fails to trigger expression of co‐stimulatory molecules B7‐1 and heat‐stable antigen on these APC. Furthermore, infection with this parasite inhibits the macrophage response to normal regulatory signals, such as bacterial lipopolysaccharide. These changes in the cell surface are mirrored in functional studies of co‐stimulation in vitro. Together, these data suggest a further facet of parasite interference in host immunity, but also indicate a potential new target for immunotherapy.
Mutation of aspartate 82 of the human C5a receptor abolishes the secretory response to human C5a in transfected rat basophilic leukemia cells
Authors: Monk Peter N. , Pease James E. , Marland Gillian , Barker Michael D. 
Published: March 2007

AbstractC5a is a potent chemoattractant for monocytes, neutrophils and other leukocytes. The receptor for human C5a is a member of the rhodopsin superfamily of G protein‐coupled receptors and contains an aspartate residue (Asp82) within the putative second transmembrane domain conserved in all other G protein‐linked receptors. We investigated the role of this residue and also the carboxy‐terminal 23 residues of the C5a receptor in ligand binding and signal transduction by expressing wild‐type and mutant receptors in the rat basophilic leukemia cell line RBL‐2H3. Wild‐type and truncated receptors coupled efficiently to effector systems, resulting in the C5a‐dependent discharge of granule contents. In contrast RBL cells transfected with receptors in which Asp82 had been mutated to asparagine did not respond to human C5a by secretion despite binding human C5a with high affinity. We conclude therefore that Asp82 is not involved in the interaction with ligand but is essential for the proper transduction of the ligand binding signal.
Immunolocalization of intracellular interleukin‐4 in normal human peripheral blood basophils
Authors: Mueller Regula , Heusser Christoph H. , Rihs Silvia , Brunner Thomas , Bullock Gillian R. , Dahinden Clemens A. 
Published: March 2007

AbstractThe question as to whether other cell types apart from helper T lymphocytes are capable of producing interleukin‐4 (IL‐4) has gained much interest over the last years. Recent studies indicate that human basophils also produce IL‐4, although direct proof is missing so far. In this study we demonstrate the presence of IL‐4 in the cytoplasm of in vitro activated human peripheral blood basophils derived from normal donors. Cytokine‐producing cells were revealed at the single‐cell level by intracellular immunofluorescence staining using IL‐4‐specific monoclonal antibodies. Basophils showed a characteristic, apparently granular staining pattern easily discerned from the eccentric dot‐shaped staining pattern in activated T cells used in control experiments. Cell counts following priming with IL‐3 and stimulation with polyclonal sheep anti‐IgE antibody or the anaphylatoxin C5a revealed a significant increase in IL‐4‐positive basophils to about 19% as compared with unprimed, unstimulated control cells (6%). The amount of IL‐4 in the supernatant of these cell preparations paralleled these observations with an at least five‐ to sevenfold increase following stimulation as compared with control cells (< 5 ng/ml). Using confocal scanning laser microscopy, the intracellular presence of IL‐4 was confirmed, and the cells were identified as being basophils on terms of their characteristic multilobed nucleus. This observation was supported by double labeling studies using antibodies to IL‐4 and to the high‐affinity IgE receptor (FcεR1). Interestingly, stimulation of cells led to a decrease in the number of FcεR1‐positive cells. The above results show direct evidence that IL‐4 is produced by activated human basophils.
Anti‐B cell autoantibodies encoded by VH 4–21 genes in human fetal spleen do not require in vivo somatic selection
Authors: Parr Tyler B. , Johnson Todd A. , Silberstein Leslie E. , Kipps Thomas J. 
Published: March 2007

AbstractWe isolated immunoglobulin (Ig) VH4 genes that were rearranged in the genomic DNA of 160 day human fetal spleen. Productively rearranged VH 4‐21 genes were cloned into pRTM1, a human IgM expression vector. This allowed us to generate IgMϰK‐expressing transfectomas by co‐transfecting each of these constructs with pSVG‐VϰK3, an Ig ϰK light‐chain expression vector that has a variable region encoded Humkv325, a conserved VϰK gene that is frequently expressed early B cell ontogeny. We find that all transfectomas expressing IgMϰK encoded by VH 4‐21 make IgM autoantibodies reactive with i, a linear poly‐N‐acetyllactosamine determinant present on neonatal red blood cells and a B cell‐restricted isoform of the CD45 surface molecule. In contrast, a transfectoma expressing pSVG‐VϰK3 and pRTM1 containing a rearranged VH4‐59 (V71‐4) gene isolated from a chronic lymphocytic leukemia B cell population, designated WIL, produced IgMϰK antibodies that had no detectable anti‐i binding activity. However, transfectomas expressing VH 4‐21 fused onto the Ig heavy‐chain third complementarity determining region (CDR3) of WIL are found to make anti‐B cell autoantibodies with anti‐i activity. These studies indicate that VH 4‐21 genes rearranged in human fetal B cell ontogeny can encode anti‐B cell autoantibodies with a binding specificity that does not require in vivo somatic selection.
A peptide encoded by human gene MAGE‐3 and presented by HLA‐A2 induces cytolytic T lymphocytes that recognize tumor cells expressing MAGE‐3
Authors: van der Bruggen Pierre , Bastin Judy , Gajewski Thomas , Coulie Pierre G. , Boël Pascale , De Smet Charles , Traversari Catia , Townsend Alain , Boon Thierry 
Published: March 2007

AbstractThe human MAGE‐3 gene is expressed in many tumors of several histological types but it is silent in normal tissues, with the exception of testis. Antigens encoded by MAGE‐3 may, therefore, be useful targets for specific anti‐tumor immunization of cancer patients. We reported previously that MAGE‐3 codes for an antigenic peptide recognized on a melanoma cell line by autologous cytolytic T lymphocytes (CTL) restricted by HLA‐A1. Here we report that the MAGE‐3 gene also codes for another antigenic peptide that is recognized by CTL restricted by HLA‐A2. MAGE‐3 peptides bearing consensus anchor residues for HLA‐A2 were synthesized and tested for binding. T lymphocytes from normal individuals were stimulated with autologous irradiated lymphoblasts pulsed with each of three peptides that showed strong binding to HLA‐A2. Peptide FLWGPRALV was able to induce CTL. We obtained CTL clones that recognized not only HLA‐A2 cells pulsed with this peptide but also HLA‐A2 tumor cell lines expressing the MAGE‐3 gene. The proportion of melanoma tumors expressing this antigen should be approximately 32 % in Caucasian populations, since 49 % of individuals carry the HLA‐A2 allele and 65 % of melanomas express MAGE‐3.
Increased susceptibility of mice infected with Schistosoma mansoni to recombinant vaccinia virus: Association of viral persistence with egg granuloma formation
Authors: Actor Jeffrey K. , Marshall Margaret A. , Eltoum Isam A. , Buller R. Mark L. , Berzofsky Jay A. , Sher Alan 
Published: March 2007

AbstractBALB/c mice infected 7 weeks previously with Schistosoma mansoni and challenged with a recombinant vaccinia virus vPE16 expressing the human immunodeficiency virus envelope protein gp160 show a marked delay in hepatic viral clearance as compared to mice infected with vPE16 alone. This increase in viral persistence is accompanied by reduced gp120‐specific Th1‐associated cytokine responses as well as by impaired cytotoxic T lymphocyte (CTL) activity against targets expressing epitopes of the same antigen. To investigate the contribution of these defects to the observed delay in clearance of recombinant vaccinia virus, animals were challenged with vPE16 at different times following S. mansoni infection, and virus titers in tissues and viral‐specific immune responses were measured simultaneously in the same animals. While normal resolution of virus occurred in schistosome‐infected mice prior to parasite egg deposition, persistence within the liver was observed in animals challenged during the onset and peak phase of granuloma formation (6 to 8 weeks after S. mansoni infection). At later times, when schistosomiasis is in its chronic phase, normal viral clearance returned. This time course of viral resolution correlated in part with the observed pattern of decreased Th1 cytokine production toward viral antigens but was clearly less temporally related to the defect in virus‐specific CTL activity. Immunohistochemical staining of liver sections from vaccinia/S. mansoni co‐infected mice with polyclonal anti‐vaccinia antibodies revealed that viral epitopes are localized primarily within granulomas. These experiments suggest that egg granulomas, by providing a microenvironment for viral expansion, in combination with the cytokine imbalance present during schistosome infection, can promote the expansion of vaccinia virus and possibly other viral agents.
IgG isotype distribution of local and systemic immune responses induced by influenza virus infection
Authors: Fazekas György , Rosenwirth Brigitte , Dukor Peter , Gergely János , Rajnavölgyi Éva 
Published: March 2007

AbstractThe IgG isotype profile of the influenza virus‐specific immune response was studied by quantitation of serum antibody (Ab) levels in correlation with the enumeration of antibody‐secreting cells (ASC) detected in the lung, spleen, mediastinal lymph nodes (MLN), Peyer's patches and bone marrow (BM). Distincst isotypic patterns for serum Ab and Ab produced by cells present at or close to the site of infection were found after primary or repeated infections. An elevated number of IgM ASC was found after primary challenge in the spleen, lung and MLN. In contrast, the site of IgA and IgG production is restricted to the lung and lymph nodes draining the site of infection. In these organs IgA, IgG2a and IgG1 ASC are found as a result of primary virus infection while viral challenge induces mostly activation of IgA‐producing cells and secretion of IgA to the lung lavage. In contrast, the majority (80‐90%) of Ab detected in the serum belong to the IgG2a subclass and their serum level is maintained at a high level during the whole period of the response. The relative level of virus‐specific serum IgG2a in correlation with the production of IgG2a Ab found predominantly in MLN and lung is highly dependent on the viral dose used for priming or challenge. As IgG2a ASC can be detected at relatively low numbers in the spleen and BM these results suggest that the production of the dominant IgG2a isotype of serum Ab occurs close to the viral challenge site. These data, however, point to distinct isotypic regulation in systemic versus local virus‐specific Ab responses.