bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plasmid DNA and protein vaccination of mice to the outer surface protein A of Borrelia burgdorferi leads to induction of T helper cells with specificity for a major epitope and augmentation of protective IgG antibodies in vivo
Authors: Zhong Weimin , Wiesmüller Karl‐Heinz , Kramer Michael D. , Wallich Reinhard , Simon Markus M. 
Published: March 2007

AbstractPlasmid DNA‐based vaccination is an efficient way to evoke various forms of protective immunity in laboratory animals. Our previous experiments have shown that mice immunized with either plasmid DNA encoding the outer surface lipoprotein A (pOspA) of Borrelia burgdorferi or the respective lipoprotein (Lip‐OspA) produce protective antibodies against subsequent challenge with virulent spirochetes. In the present study, we compared the specificity and function of T cells generated in AKR/N mice previously immunized to either pOspA or Lip‐OspA. T cell populations derived by either of the two protocols consistently responded by proliferation in vitro to one (residues 186–203; B4) out of a panel of 27 overlapping 20‐mer peptides spanning the entire OspA molecule of strain ZS7. B4 was shown to express allele‐specific ligand motifs for I‐Ek. Most of the other peptides produced variable and much less pronounced or marginal proliferative T cell responses. T cells reactive to B4 as well as to some minor epitopes were CD4+CD8− T cells which produced IFN‐γ but no detectable IL‐4 upon antigen stimulation in vitro Priming of AKR/N mice with B4 but not with inactive peptides of OspA led to an enhanced production of IgG antibodies, mainly of the IgG1 isotype, including those to a prominent protective epitope (LA‐2) upon subsequent challenge with Lip‐OspA or intact spirochetes. The data demonstrate that both plasmid DNA and protein immunization with OspA results in T cell responses with specificity for a dominant OspA epitope and suggest that priming of mice with immunodominant peptides accelerates the appearance of protective antibodies in vivo. The identification of T helper cell epitopes relevant for the induction of protective antibodies will also facilitate the design of more potent vaccines against Lyme disease.
IsXenopusIgX an analog of IgA?
Authors: Mußmann Rainer , Du Pasquier Louis , Hsu Ellen 
Published: March 2007

AbstractUsing class specific monoclonal antibodies we analyzed the tissue distribution of B cells expressing the three immunoglobulin (Ig) isotypes (IgM, IgX, IgY) inXenopus. Large numbers of IgM‐ and IgX‐, but not IgY‐, positive B cells are located in the gut epithelium of the intestine. In this organ up to 60% of all B cells can be IgX positive, while in the spleen or liver they are hardly detectable. The majority of IgX‐producing cells resemble plasma cells. IgY‐producing cells are found in the liver and spleen but not in the intestine. In contrast to IgY, the expression of IgM and IgX is thymus independent. Upon systemic immunization, a several‐fold increase of specific IgM and IgY, but not IgX, antibodies was detected in the sera. This and its association with the mucosae of the intestine resembles results reported for mammalian IgA; therefore, IgX ofXenopusmight be considered an analog of IgA.
Interleukin‐10 and interleukin‐4 have similar effects on hapten‐specific primary antibody responses to penicillin in vivo
Authors: Kerdine Saadia , Pallardy Marc , Lamanètre Sandrine , Bertoglio Jacques , Lebrec Hervé 
Published: March 2007

AbstractInterleukin (IL)‐10 was initially recognized on the basis of its capacity to inhibit production of interferon (IFN)‐γ by T helper (Th)1 lymphocytes; we examined whether this cytokine can bias the primary antibody (Ab) response to the hapten penicillin. We previously reported that BALB/c and SJL mice develop different responses to benzylpenicillin coupled to tetanus toxoid (BPO‐TT). The response of SJL mice was characterized as Th2 on the basis of early and high IL‐4 mRNA expression and production of BPO‐specific Ab of the IgG1 isotype. In contrast, the response of BALB/c mice was characterized as Th1 on the basis of delayed and weaker IL‐4 mRNA expression associated with high anti‐BPO IgG2a production (Kerdine, S. et al., Mol. Immunol. 1996. 33: 71). In this report, we demonstrate that in naive animals, the level of expression of IL‐10 mRNA in LN cells was high in SJL and barely detectable in BALB/c. In addition, injection of BPO‐TT resulted in rapid and large increase of IL‐10 mRNA expression in SJL. Neutralization of IL‐10 in vivo promoted the production of BPO‐specific IgG2a in SJL, and injection of IL‐10‐CHO cells inhibited BPO‐specific IgG2a production in BALB/c. Neutralization on administration of IL‐10 had effects very similar to neutralization or administration of IL‐4. However, co‐neutralization of IL‐10 and IL‐4 in SJL did not evidence additive or synergistic effects of the two cytokines. Administration of IL‐10 or IL‐4 in BALB/c inhibited BPO‐TT‐induced expression of IL‐12 p40 mRNA without modulating IFN‐γ mRNA. Together, these data demonstrate that endogenous production of IL‐10 regulates the production of IgG2a Ab in response to BPO‐TT and that IL‐10, like IL‐4, is critical for controlling primary responses to antibiotics which behave as haptenic compounds.
Homeostatic regulation of CD8+ T cells after antigen challenge in the absence of Fas (CD95)
Authors: Zimmermann Christine , Rawiel Marlies , Blaser Claudine , Kaufmann Martina , Pircher Hanspeter 
Published: March 2007

AbstractThe role of Fas in the homeostatic regulation of CD8+ T cells after antigen challenge was analyzed in the murine model of lymphocytic choriomeningitis virus (LCMV) infection. Mice homozygous for the lpr mutation and carrying T cell receptor (TCR) αβ transgenes specific for the LCMV glycoprotein peptide aa 33–41 in the context of H‐2Db were used. Five main results emerged: first, development of lymphadenopathy and of CD4−CD8− double‐negative B220+ T cells in lpr mice was not inhibited by the αβ TCR transgenes; second, tolerance induction and peripheral deletion of CD8+ T cells induced by LCMV glycoprotein peptide injection was independent of Fas expression; third, clonal down‐regulation of Fas‐deficient TCR‐transgenic CD8+ T cells after acute LCM virus infection was identical to the decline of transgenic T cells expressing Fas; fourth, in vivo activated CD8+ effector T cells from TCR transgenic and TCR‐lpr/lpr mice were equally susceptible to activation‐induced cell death in vitro; and fifth, transgenic effector T cells from lpr/lpr mice were cleared in the declining phase of the immune response in vivo without giving rise to CD4−CD8− double‐negative T cells. Taken together, these data suggest that the homeostatic regulation of CD8+ T cells after antigen challenge in vivo is regulated by mechanisms that do not require Fas.
CD40 signaling induces interleukin‐4‐independent IgE switching in vivo
Authors: Ferlin Walter G. , Severinson Eva , Ström Lena , Heath Andrew W. , Coffman Robert L. , Ferrick David A. , Howard Maureen C. 
Published: March 2007

AbstractT cell‐deficient T cell receptor (TCR) β−/− x TCR δ−/− knockout mice lack circulating IgE and fail to produce antigen‐specific IgE in response to stimulation with T cell‐dependent antigens. We show here that these animals are able to produce significant levels of circulating polyclonal IgE when injected with an agonistic anti‐mouse CD40 monoclonal antibody. CD40‐mediated induction of circulating polyclonal IgE in T cell‐deficient mice was only partially reduced when the animals were co‐treated with neutralizing anti‐interleukin‐4 (IL‐4) antibody. The IL‐4 independence of this response was further supported by experiments showing that anti‐CD40 antibodies induced circulating IgE when injected into IL‐4 knockout mice, and sterile RNA ϵ transcript production when cultured with purified B cells from the same mice. These data strongly suggest that CD40 signaling causes IL‐4‐independent IgE switching in mice.
Monocytes induce E‐selectin gene expression in endothelial cells: role of CD11/CD18 and extracellular matrix proteins
Authors: Noble Karen E. , Panayiotidis Panayiotis , Collins Peter W. , Hoffbrand A. Victor , Yong Kwee L. 
Published: March 2007

AbstractE‐selectin is an endothelium‐specific inducible adhesion molecule which binds several inflammatory cell types, including neutrophils, monocytes, natural killer cells and a subset of memory T cells. E‐selectin is important in the initial rolling interaction of these cells on inflamed endothelium. The transient kinetics of E‐selectin induction in vitro contrast with in vivo observations of prolonged expression of this adhesion molecule in chronic inflammation. This raises the possibility that signals generated within inflammatory tissues are more complex than the agonists used to activate endothelial cells in vitro. We investigated whether adhesive interactions with extravasating monocytes are able to provide activating signals that can induce E‐selectin expression on endothelium, and prolong the response to cytokine stimulation. We report that co‐culture with monocytes led to transcriptional activation of the E‐selectin gene in endothelial cells, and marked enhancement of the response to substimulatory concentrations of interleukin‐1. In addition, the presence of monocytes resulted in prolonged up‐regulation of E‐selectin. Induction of E‐selectin by monocytes was inhibited when cell contact between monocytes and endothelium was prevented (80 ± 8% inhibition, p < 0.001, n = 4). Monoclonal antibody (mAb) against tumor necrosis factor (TNF) was able to abolish 57.2 ± 9.7% of the response (p < 0.01, n = 4). The ability of adherent monocytes to induce sustained E‐selectin expression in endothelial cells could not be reproduced either by supernatants harvested from monocytes cultured for 18 h, or by maximal concentrations of TNF. The induction of E‐selectin in monocyte/endothelium co‐cultures was inhibited by mAb to CD11b, but not by those directed against VLA‐4 or L‐selectin. Extracellular matrix molecules may also play a role in adhesion‐dependent cellular activation, as inclusion of soluble collagen type I led to significant reduction in E‐selectin expression in monocyte/endothelium co‐cultures. We conclude that adhesive interactions between monocytes and endothelial cells provide a source of signals which influence the activation state of the endothelium, and consequently, the continued influx of inflammatory cells.
Phenotype and function of human B cells expressing CD70 (CD27 ligand)
Authors: Lens Susanne M. A. , De Jong Rolien , Hooibrink Berend , Koopman Gerrit , Pals Steven T. , van Oers Marinus H. J. , van Lier René A. W. 
Published: March 2007

AbstractCD70, the cellular ligand of the tumor necrosis factor receptor family member CD27, can be found on a limited number of germinal center (GC) B cells in some tonsils, on scattered lymphocytes residing in secondary lymphoid organs, and on a fraction of the circulating B cell population. Due to the restricted expression of CD70 in vivo, we analyzed signals that determine CD70 expression levels and characterized the phenotype and function of CD70+ B cells. Expression of CD70 on B cells activated in vitro was found to be dependent on the continuous presence of a B cell antigen receptor cross‐linking agent, and induced or potentiated by CD40 ligation but was down‐modulated by the Th2 cytokines interleukin (IL)‐4 and IL‐13. Both in peripheral blood and tonsil cell suspensions, CD70+ B cell subpopulations were found to be enriched for CD27‐and IgG‐expressing cells, but contained less IgD+ B cells. Additional analysis of markers which define specific differentiation stages (Bm1‐5) of mature B cells within human tonsils did not place CD70‐expressing B cells in one of these subsets. Functional experiments revealed that whereas both CD70− and CD70+ B cells can secrete immunoglobulin after activation with a combination of Staphylococcus aureus Cowan strain I and IL‐2, only CD70+ B cells can produce large quantities of antibodies when stimulated in a T cell‐dependent fashion. Our combined data imply that CD70 is a marker for mature B cells which have recently been primed by antigen in vivo.
Potential allergens stimulate the release of mediators of the allergic response from cells of mast cell lineage in the absence of sensitization with antigen‐specific IgE
Authors: Machado Denise C. , Horton Donna , Harrop Richard , Peachell Peter T. , Helm Birgit A. 
Published: March 2007

AbstractA number of structurally diverse antigens preferentially stimulate the synthesis of IgE antibodies, but no unifying principle has been proposed that explains the nature of isotype selection. In the present study, we show that common allergens present in bee venom, house dust mite emanations and parasite proteins induce mast cell and basophil degranulation and stimulate interleukin‐4 synthesis, and secretion in the absence of antigen‐specific IgE. These data point to a linkage between the initial activation of cells of the innate immune system and subsequent adaptive immune responses. They suggest that IgE‐independent mast cell and basophil degranulation is predictive of potential allergenicity and can be evaluated by means of a cellular assay. Our study indicates that non‐immunological degranulation by prototypic allergens, such as bee venom phos‐pholipase A2 or proteases associated with house dust mite emanations, is critically dependent on enzymatic activity. These findings have potentially important implications for vaccine design in allergic and parasitic disease.
Molecular cloning and chromosomal mapping of a novel human gene, ChemR1, expressed in T lymphocytes and polymorphonuclear cells and encoding a putative chemokine receptor
Authors: Samson Michel , Stordeur Patrick , Labbé Olivier , Soularue Pascal , Vassart Gilbert , Parmentier Marc 
Published: March 2007

AbstractWe describe the cloning of a human gene, named ChemR1, encoding a new putative chemokine receptor sharing 48% identity with CC‐chemokine receptor (CCR)4 and 44% identity with CCR1. It displays four extracellular cysteines that are conserved among all other chemokine receptors. ChemR1 transcripts were detected by Northern blotting in the T lymphoblastic cell lines Jurkat and MOLT‐4, but not in the pre‐B lymphoblastic cell line JM‐1. ChemR1 receptor transcripts were also detected by reverse transcription and polymerase chain reaction analysis in unstimulated CD4+ and CD8+ T cells and polymorphonuclear cells prepared from peripheral blood. The chromosomal localization was performed by radiation hybrid mapping and testing of a panel of yeast artificial chromosome clones. This allowed the assignment of the ChemR1 receptor gene to the p21.3‐24 region of human chromosome 3, in close proximity with the functionally characterized CCR. Future work is required to identify the ligand(s) of this new chemokine receptor and to define its role in the recruitment of white blood cell populations.
Spontaneously produced anti‐DNA/DNase I autoantibodies modulate nuclear apoptosis in living cells
Authors: Madaio Michael P. , Fabbi Marina , Tiso Micaela , Daga Antonio , Puccetti Antonio 
Published: March 2007

AbstractApoptosis has received increased attention over the past decade, and it is established as an essential process in physiological and disease states. Much effort has been devoted to understanding the intracellular mechanisms culminating in apoptosis; intense investigation has also focused on its role during inflammation. Despite these efforts, these events remain incompletely understood. It has been suggested that the Ca2+‐ and Mg2+‐dependent endonuclease that mediates DNA fragmentation is DNase I; however, the precise role of DNase I during apoptosis has been debated. Recent observations using anti‐DNA antibodies derived from autoimmune mice (MRL‐lpr/lpr) provided both the means and the reagents to approach these issues in a more direct manner. We previously discovered that many anti‐DNA antibodies cross‐react with DNase I, and a subset of these Ig inhibited DNase I enzymatic activity in vitro. Serendipitously, in separate studies, a subset of these antibodies were observed to enter and localize within the nuclei of living cells. The aim of the present investigation was to determine whether these nuclear‐localizing anti‐DNA antibodies could interact with DNase I in living cells. We found that, once internalized, these autoantibodies bound DNase I and inhibited activity of the enzyme. Furthermore, living cells containing the intracellular antibodies appeared resistant to apoptotic stimuli; both morphological features of nuclear apoptosis and DNA fragmentation were inhibited. These results support a pivotal role for DNase I in apoptosis, and they provide a novel paradigm for autoantibody‐mediated inflammatory disease.
Direct cell/cell contact with stimulated T lymphocytes induces the expression of cell adhesion molecules and cytokines by human brain microvascular endothelial cells
Authors: Lou Jinning , Dayer Jean‐Michel , Grau Georges E. , Burger Danielle 
Published: March 2007

AbstractUpon inflammation, stimulated, but not resting T lymphocytes cross the blood‐brain barrier and migrate into the central nervous system. This study shows that direct contact between stimulated T lymphocytes and human brain microvascular endothelial cells (HB‐MVEC) induces phenotypic and functional changes on the latter cells. Plasma membranes isolated from stimulated T lymphocytes (S‐PM) up‐regulated the expression of intercellular adhesion molecule‐1 (ICAM‐1), vascular cell adhesion molecule‐1 (VCAM‐1), and E‐selectin on isolated HB‐MVEC. In addition, HB‐MVEC activated by S‐PM secreted interleukin (IL)‐6 and IL‐8. The levels of ICAM‐1, E‐selectin, IL‐6, and IL‐8 expressed in S‐PM‐activated HB‐MVEC were similar to those observed with 1000 U/ml tumor necrosis factor (TNF). In contrast, VCAM‐1 expression was 15% of that induced by TNF. Inhibitors of TNF diminished (≤ 45 %), but did not abolish the expression of cell adhesion molecules and IL‐6 induced by S‐PM, IL‐8 production being insignificantly affected (≤ 10 %). This suggests that membrane‐associated TNF was partially involved in HB‐MVEC activation. The present study demonstrates that stimulated T lymphocytes are able to activate HB‐MVEC upon direct cell contact. This novel mechanism of inducing the expression of cell adhesion molecules may prompt the initial adhesion of stimulated T lymphocytes to brain endothelium.
Modulation of Apo‐1/Fas (CD95)‐induced programmed cell death in myeloma cells by interferon‐α2
Authors: Egle Alexander , Villunger Andreas , Kos Marion , Böck Günther , Gruber Johann , Auer Bernhard , Greil Richard 
Published: March 2007

AbstractThe Apo‐1/Fas (CD95) antigen is known to be involved in the process of T cell‐mediated target cell killing and has recently been shown to be expressed on myeloma cell lines and native malignant plasma cells. Several cytokines have been reported to interfere with spontaneous and even Apo‐1/Fas‐induced apoptosis, but no attempt has been made yet to investigate these interactions and the possible underlying mechanisms in myeloma cells. Since in myeloma patients Interferon (IFN)‐α2 displays a profound therapeutic effect in vivo, which is usually attributed to its growth inhibitory and/or immunomodulatory capacity, we set out to study the potential interference of IFN‐α2 with Apo‐1/Fas‐induced apoptosis. Contrary to expectations, IFN‐α2 reduced the degree of apoptosis caused by the treatment of five Apo‐1/Fas‐sensitive myeloma cell lines with a Fas monoclonal antibody (mAb). Simultaneous application of IFN‐α2 and Fas mAb was superior to the prolonged (i.e. > 8 h) preincubation with the cytokine as far as inhibition of Apo‐1/Fas‐induced apoptosis was concerned. This effect of IFN‐α2 was neither explained by a down‐regulation of the Apo‐1/Fas receptor nor caused by modulation of the expression levels of c‐myc, bcl‐2‐, bcl‐xL, bax‐ or p53 genes. IFN‐α2 did not alter the Apo‐1/Fas‐induced activity of Mitogen‐activated protein kinase (MAPK) 1 and did not inhibit the Apo‐1/Fas‐mediated proteolytic cleavage of ADP‐ribosyltransferase, a substrate of Interleukin‐β1 converting enzyme (ICE) and homologues. However, activation of protein kinase C (PKC) by phorbol 12‐myristate 13‐acetate (PMA) mimicked the effects of IFN‐α2. Furthermore, the bis‐indolylmaleimide GF 109203X, a specific inhibitor of PKC, inhibited the effect of PMA as well as that of IFN‐α2 on Apo‐1/Fas‐induced apoptosis. These results point to a PKC‐dependent mechanism of transient interaction between the intracellular signaling along the IFN‐α2 and the Apo‐1/Fas pathway (downstream of MAPK signaling as well as of ICE homologues), which becomes exhausted by prolonged stimulation with the cytokine. According to our data IFN‐α2, applied continuously and in high doses resembling the therapeutic situation in vivo, inhibits myeloma growth. However, based on the observed inhibitory effect of IFN‐α2 on Apo‐1/Fas‐induced apoptosis, a partial inhibition of the natural immune surveillance on myeloma cells by endog‐genous IFN‐α2 present in the bone marrow microenvironment of this malignancy should be investigated.
Mouse polymorphonuclear granulocyte binding to extracellular matrix molecules involves β1 integrins
Authors: Frieser Michael , Hallmann Rupert , Johansson Staffan , Vestweber Dietmar , Goodman Simon L. , Sorokin Lydia 
Published: March 2007

AbstractThe mechanism of adhesion of purified mouse polymorphonuclear granulocytes (PMN) to extracellular matrix proteins characteristic of basement membranes and the interstitium has been investigated and compared with the adhesion of a mouse progranulocytic cell line, 32DC13, and a mouse monocytic cell line, WEHI 78/24. All three cell types bound specifically to fibronectin and vitronectin to different degrees under different cellular activation states. 32DC13 bound to fibronectin and vitronectin strongly, and this binding increased upon cellular activation with phorbol 12‐myristate‐13‐acetate (PMA) but not with formyl‐Met‐Leu‐Phe. Only 32DC13 showed significant binding to laminin‐1. By contrast, WEHI 78/24 and PMN bound only fibronectin and vitronectin; this binding was weak and was altered only marginally upon activation with PMA. In the case of WEHI 78/24, a slight increase in adhesion both to fibronectin and to vitronectin was observed after cellular activation with PMA, while PMN adhesion to both substrates was slightly reduced. The mechanism of binding to fibronectin and vitronectin was similar in the three cell types. The integrin α5β1 mediated fibronectin adhesion, demonstrating for the first time the existence of a functionally active β1 integrin on mouse PMN. Vitronectin binding was mediated by αvβ3, as demonstrated by the ability of αv‐specific cyclic L‐Arg‐L‐Gly‐L‐Asp‐D‐Phe‐L‐Val (RGDfV) peptide (EMD66203), and anti‐β3 antibody to inhibit cell adhesion. 32DC13 adhesion to laminin‐1 was via the α6β1 integrin. None of the three cell types tested bound to the basement membrane proteins collagen type IV and perlecan, or to the interstitial stromal constituents tenascin, collagen types I, V and VI. Interestingly, perlecan and collagen type IV were found to repel all three cell types. The relative inability of PMN, WEHI 78/24, and 32DC13 to bind to extracellular matrix proteins characteristic of basement membranes and their ability to bind inflammatory markers of the interstitium is discussed with respect to leukocyte extravasation processes.