bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural properties and mutation patterns of anti‐nucleosome monoclonal antibodies are similar to those of anti‐DNA antibodies
Authors: Brard Frédéric , Jovelin Fabien , Petit Samuel , Tron François , Gilbert Danièle 
Published: March 2007

AbstractFour monoclonal antibodies (mAb) derived from an (NZB × NZW)F1 mouse bound to nucleosomes, total histones and to the H2A‐H2B dimers but not to individual histones or DNA. Sequencing of their heavy (H)‐ and light (L)‐chain variable region genes showed that they derived by somatic mutations from the same B cell precursor. The distribution of negatively and positively charged amino acids in the H‐chain complementarity‐determining regions was very similar to that observed not only in anti‐H2A‐H2B mAb derived from different lupus‐prone mouse strains but also in anti‐DNA mAb. Combined analysis of the mAb structures and their interactions with immobilized H2A‐H2B dimer or total histones by plasmon resonance allowed us to assign the H‐chain mutations a major role in the binding profiles of these anti‐nucleosome mAb. Interestingly, four of the five H‐chain mutations that distinguished mAb 3F6 from 2E1 generated negatively or positively charged amino acid residues, and two of them occurred at positions 56 and 76, which are frequently involved in the maturation process of anti‐DNA antibodies. A modeling study of the 3F6 variable fragment (Fv) predicted that acidic residues occupy the cleft of the Ab combining site and have the potential to participate in electrostatic interactions. Thus, the demonstration that (NZB × NZW)F1‐derived anti‐H2A‐H2B antibodies share certain structural features and mutation patterns with anti‐DNA mAb suggest that common selection and maturation processes account for the production of these lupus‐related autoantibodies.
Germinal center formation in mice lacking αβ T cells
Authors: Dianda Lee , Gulbranson‐Judge Adam , Pao William , Hayday Adrian C. , Maclennan Ian C. M. , Owen Michael J. 
Published: March 2007

AbstractT cells are essential for inducing clonal B cell expansion in germinal centers during T cell‐dependent antibody responses. However, class‐switched antibodies are readily detectable in TCRα‐deficient mice that congenitally lack αβ T cells, including those such as IgG1 that are considered to be dependent on collaboration between B cells and αβ T cells. This observation suggests that a novel form of B:T collaboration may be evident in TCRα−/− mice. We report that germinal centers develop spontaneously in mice lacking T cell receptor α genes (TCRα−/−), despite the absence of αβ T cells. They are not seen in TCRβ−/− mice kept in similar conditions. Both strains of mice have γδ T cells, but it is a subset of T cells expressing TCRβ and CD4 that is dominant in the germinal centers of TCRα−/− mice. Exceptionally, germinal centers were associated with CD4+ γδ T cells. The expression of CD4 seems to be important, for few extrafollicular T cells have CD4 and CD4 is largely absent from TCRβ−/− T cells. The CD4+ TCRβ cells may help B cells produce autoantibodies that have been identified in TCRα−/− mice.
Glutamine and tetrapeptide repeat variations affect the biological activity of different mouse interleukin‐2 alleles
Authors: Matesanz Fuencisla , Alcina Antonio 
Published: March 2007

AbstractMouse interleukin‐2 (IL‐2) was thought to be encoded by a single allele. We have recently described N‐terminal differences in five IL‐2 molecules from nine mouse strains analyzed (Matesanz, F., Alcina, A. and Pellicer, A., Immunogenetics 1993. 38: 300). In this study, we isolated and sequenced the cDNA of three polymorphic IL‐2 molecules and constructed two recombinant IL‐2 molecules to cover representative structural changes and to address the functional significance of these changes using human and mouse cellular assays in vitro. Apart from punctual codon changes, major differences include an expanding CAG codon (translated into glutamine) and the presence of the tetrapeptide Pro‐Thr‐Ser‐Ser repeated 1, 2, or 3.5 times which is also present once in human IL‐2. This tetrapeptide repeat includes an O‐glycosylation site. These recombinant IL‐2 proteins were expressed at high levels in bacteria and purified by preparative SDS‐PAGE with a complete activity recovery. Differences in growth‐inducing activity on mouse primary splenocytes were observed in some of them, although no differences were observed in proliferative stimulation of CTLL cells. In human peripheral blood lymphocytes and the T cell line Kit‐225, the growth stimulation capacity was inversely dependent on the size of the glutamine stretch and the number of tetrapeptide repeats. These results suggest an evolutionary adaptation of the mouse IL‐2/IL‐2 receptor system that maintains polyglutamine extensions in the IL‐2 molecule. In summary, mouse IL‐2 polymorphism results in different bioactivities which may determine susceptibility or resistance to disease.
A soluble deletion mutant of the human complement receptor type 1, which lacks the C4b binding site, is a selective inhibitor of the alternative complement pathway
Authors: Scesney Susanne M. , Makrides Savvas C. , Gosselin Michael L. , Ford Pamella J. , Andrews Beth M. , Hayman Edward G. , Marsh Henry C. 
Published: March 2007

AbstractThe human complement receptor type 1 (CR1, CD35), is a single‐chain glycoprotein consisting of 30 repeating homologous protein domains known as short consensus repeats (SCR) followed by transmembrane and cytoplasmic domains. The SCR themselves, considered in groups of seven, form long homologous repeats (LHR) which have been designated LHR‐A, ‐B, ‐C, and ‐D for the most common human allotype of CR1. A soluble deletion mutant of CR1 which lacks the first seven N‐terminal SCR (LHR‐A) as well as the transmembrane and cytoplasmic domains was produced and characterized. The resulting protein, designated sCR1[desLHR‐A], lacks the C4b binding site found in LHR‐A, but retains the two C3b binding sites found in LHR‐B and ‐C, respectively. The functional activities of sCR1[desLHR‐A] were quantitatively compared in vitro to those of soluble complement receptor type 1 (sCR1) which has been shown to retain all known functions of the native cell surface receptor. sCR1[desLHR‐A] and sCR1 competed equally for the binding of dimeric C3b to erythrocyte CR1. sCR1[desLHR‐A] and sCR1 were similar in their capacity to serve as a cofactor in the factor I‐mediated degradation of the C3b and C4b α chains. sCR1[desLHR‐A] and sCR1 were comparable in their capacity to inhibit erythrocyte lysis and anaphylatoxin production mediated by the alternative complement pathway. sCR1[desLHR‐A], however, was significantly less effective an inhibitor of erythrocyte lysis and anaphylatoxin production than sCR1 under conditions which allow classical pathway activation. These results demonstrate sCR1[desLHR‐A] to be a selective inhibitor of the alternative complement pathway in vitro.
Association of phosphatidylinositol 3 kinase to protein kinase C ζ during interleukin‐2 stimulation
Authors: Gómez Javier , Martínez‐A Carlos , García Alphonse , Rebollo Angelita 
Published: March 2007

AbstractInterleukin‐2 induces a serine‐phosphorylated phosphatidylinositol 3 kinase activity in the mouse T cell line TS1αβ. Moreover, protein kinase C (PKC) ζ directly or indirectly associates with the phosphatidylinositol 3 kinase and the association appears to be necessary for the serine‐phosphorylated phosphatidylinositol 3 kinase activity, since release of ζPKC by competition of binding with peptides spanning the p110 sequence from amino acids 907 to 925 abolishes the serine‐phosphorylated phosphatidylinositol 3 kinase activity. This kinase activity is also blocked when ζPKC expression is inhibited by antisense oligonucleotide. Inhibition of phosphatidylinositol 3 kinase activity by wortmannin does not abolish ζPKC association.
Regulation of cathepsin E expression during human B cell differentiation in vitro
Authors: Sealy Louise , Mota Fernando , Rayment Neil , Tatnell Peter , Kay John , Chain Benjamin 
Published: March 2007

AbstractCathepsin E is an aspartic proteinase which has been implicated in antigen processing in the class II major histocompatibility complex pathway. In this study we show that cathepsin E, measured at both the protein and message level, is up‐regulated late in human B cell activation. The implications of this observation in terms of cathepsin E function are discussed.
A strict requirement of interleukin‐4 for interleukin‐4 induction in antigen‐stimulated human memory T cells
Authors: Breit Susanne , Steinhoff Matthias , Blaser Kurt , Heusser Christoph H. , Sebald Walter , Levine Alan D. , Röcken Martin 
Published: March 2007

AbstractThe role of interleukin‐4 (IL‐4) in the induction of IL‐4 in mouse T cells is well established, but conflicting results have been reported with anti‐CD3‐primed human T cells and T cell clones. Therefore, IL‐4 regulation was investigated in short‐term cultured human T cells primed in vitro with either a superantigen or a hapten, nickel sulfate (NiSO4), for 3 days and expanded with IL‐2 for another 5 days. Under these conditions, antigen‐specific IL‐4 producing T cells were generated in 35 / 40 cultures. Priming for IL‐4 production was abrogated in all cultures by anti‐IL‐4 antibody or soluble IL‐4 receptor (sIL‐4R). Primed T cells that were IL‐4− when cultured with IL‐2 only developed an IL‐4 producing phenotype when primed and expanded in the presence of exogenous IL‐4. T cells primed in the presence of either endogenous or exogenous IL‐4 produced 10–200‐fold more IL‐4 than T cells primed in the presence of anti‐IL‐4 antibody or sIL‐4R. While IL‐4 induction was absolutely dependent on IL‐4, neither endogenous nor exogenous IL‐4 influenced IFN‐γ synthesis. Most importantly, IL‐4 induced and sIL‐4R abolished priming for IL‐4 production even in NiSO4‐specific memory T cells from sensitized individuals. Thus, IL‐4 induction in antigen‐specific human memory T cell populations absolutely required IL‐4. The IL‐4 pathway of memory T cells retained a remarkable plasticity in sensitized individuals.
The relative importance of individual DR binding motif positions as defined by peptide anchor analysis of influenza hemagglutinin peptide 306–318 and human myelin basic protein peptide 152–165 binding to several DR molecules: definition of a common extended DR binding motif
Authors: Posch Phillip E. , Hastings Alice E. , Rosen‐Bronson Sandra , Richert John R. , Hurley Carolyn Katovich 
Published: March 2007

AbstractDefinition of peptide binding motifs for DR molecules has proven difficult as the peptides that bind to a DR molecule have shown extensive variability at putative motif positions. Recent studies suggest that specific peptide anchor residues (motif positions) and specific DR residues can differ in importance for peptide binding to a DR molecule. To assess further the relevance of individual peptide anchor residues, the binding of serial alanine‐substituted analogs of influenza virus hemagglutinin (HA) 306–318 and human myelin basic protein (MBP) 152–165 to a panel of transfected wild‐type DR molecules was examined. This analysis included DR molecules from a wide range of allelic families and, unlike most earlier studies, multiple members of single DR allelic families. The data show that different peptide residues serve as critical anchors for binding to different DR molecules. For example, MBP binding to DR(α,β1*0303) required peptide residues F154 (i), R159 (i + 5) and R162 (i + 8). In contrast, MBP binding to DR(α,β1*0102) required peptide residues I153 (i) and L156 (i + 3). More importantly, the combination of critical anchor residues in HA and MBP differed for binding to a single DR molecule [e.g. V309 (i) for HA and I153 (i) and L156 (i + 3) for MBP binding to DR(α,β1*0102)]. Although the location of the binding pocket in each DR molecule compared to the DR (α,β1*0101) crystal is expected to be similar and suggests a common extended DR binding motif, the present results suggest that the relative importance of individual peptide anchor residues and of the corresponding DR binding pockets will differ for each DR/peptide complex.
Relative location of epitopes involved in synergistic antibody binding using human chorionic gonadotropin as a model
Authors: Klonisch Thomas , Delves Peter J. , Berger Peter , Panayotou George , Lapthorn Adrian J. , Isaacs Neil W. , Wick Georg , Lund Torben , Roitt Ivan M. 
Published: March 2007

AbstractWe systematically screened a large panel of well‐characterized monoclonal antibodies (mAb) directed towards various epitopes on human chorionic gonadotropin (hCG) for synergistic binding of 125I‐hCG when they were adsorbed to a solid phase. The epitope locations involved in synergy were then related to the crystal structure of hCG and discussed in accordance with available data on the hCG epitopes. Enhanced binding of hCG was specific for certain pairs of mAb and was reflected in a 3–50‐fold increased apparent functional affinity constant for hCG. Surface plasmon resonance revealed that when the mAb were captured by a polyclonal anti‐IgG1 coupled to the Biacore chip, the off rates for hCG were significantly slower with synergistic mAb combinations than for the corresponding single mAb or nonsynergistic pairs of mAb, whereas the on rates did not differ appreciably. Each of the two antibodies involved in synergistic binding of hCG (more than 3‐fold compared to additive binding of the two mAb) always belonged to a different epitope cluster in a separate antigenic domain on hCG. Synergistic epitope combinations on holo‐hCG were located in similar structural planes. Combinations of mAb directed towards the epitope clusters α2/β3/5, α2/hCGβCTP (C‐terminal peptide) and β3/5/hCGβCTP showed the strongest enhancement, with binding more than 10‐fold greater than the sum of 125I‐hCG bound to the individual mAb, followed by pairs of mAb directed towards the epitope groups β1/β3/5, c1/2/β3/5, β1/α2, and α2/α3/5 (3–9‐fold). The greater frequency of synergy obtained with the linear epitopes of the hCGβCTP can be ascribed to their greater molecular flexibility relative to the constrained discontinuous epitopes on hCGα and core‐hCGβ (residues 1–112). In general, these studies provide a method for rapid screening of synergistic antibody pairs which also helps to identify non‐overlapping epitopes that are accessible in similar structural planes. In turn, this facilitates the design of high‐affinity bispecific antibodies targetted to a single antigen molecule.
Antigen processing and presentation of a naturally glycosylated protein elicits major histocompatibility complex class II‐restricted, carbohydrate‐specific T cells
Authors: Michaëlsson Erik , Broddefalk Johan , Engström Åke , Kihlberg Jan , Holmdahl Rikard 
Published: March 2007

AbstractIt is well known that T cells recognize antigen as processed peptides bound to major histocompatibility complex molecules on the surface of antigen‐presenting cells. Recently, it has been shown that T cells can specifically recognize synthetic glycopeptides. However, whether glycopeptides are selected for presentation during antigen processing of glycoproteins and eventually elicit carbohydrate‐specific T cells is still an open question. In this study, we utilized synthetic glycopeptides to analyze T cell recognition of the naturally glycosylated immunodominant peptide representing type II collagen (CII) residues 256–270. In this peptide, lysines at positions 264 and 270 may be post‐translationally modified by hydroxylation and subsequent O‐linked glycosylation with β‐galactosyl or α‐glucosyl‐(1 → 2)‐β‐galactosyl residues. T cell hybridomas established from type II collagen‐immunized mice specifically recognized CII 256–270 with either galactose or glucosyl‐galactose at position 264. The T cell hybridoma recognizing glucosyl‐galactose displayed no cross‐reactivity either to galactose or to the structurally different α‐galactosyl‐(1 → 4)‐β‐galactose. Furthermore, the T cell hybridoma recognizing galactose did not cross‐react to glucosyl‐galactose or galactosyl‐galactose, indicating that the antigen‐presenting cells (bulk spleen cells, lipopolysaccharide‐stimulated spleen cells, anti‐CD40‐stimulated spleen cells, peritoneal exudate cells or CFA‐primed lymph node cells) inefficiently processed carbohydrates when the antigen was given as a glycopeptide.
Comparison of numerous delivery systems for the induction of cytotoxic T lymphocytes by immunization
Authors: Allsopp Catherine E. M. , Plebanski Magdalena , Gilbert Sarah , Sinden Robert E. , Harris Steve , Frankel Gadi , Dougan Gordon , Hioe Catarina , Nixon Douglas , Paoletti Enzo , Layton Guy , Hill Adrian V. S. 
Published: March 2007

AbstractA variety of vaccine delivery systems including peptides with various adjuvants, recombinant particles, live recombinant viruses and bacteria and plasmid DNA were tested for their ability to induce CD8+ cytotoxic T lymphocytes (CTL) against a well‐defined epitope (amino acids 252–260) from the circumsporozoite (CS) protein of Plasmodium berghei. We compared routes of immunization that would be applicable for the administration of a malaria vaccine in humans. The majority of these vaccines did not induce high CTL responses in the spleens of immunized mice. However, both a yeast‐derived Ty virus‐like particle expressing the optimal nine‐amino acid epitope SYIPSAEKI from the CS protein (CSP‐VLP) and a lipid‐tailed peptide of this same sequence induced high levels of the major histocompatibility complex (MHC) class I‐restricted CTL with one and three subcutaneous immunizations, respectively. Moreover, these CTL were able to recognize naturally processed antigen expressed by a recombinant vaccinia virus. The levels of CTL induced by CSP‐VLP could be augmented by co‐immunization with certain cytokines. Target cells pulsed with CSP‐VLP were recognized and lysed, showing that the particles were effectively processed and presented through MHC class I presentation pathway. The levels of CTL induced using CSP‐VLP and lipopeptides are comparable to those observed after immunization with multiple doses of irradiated sporozoites.
Processing of pro‐tumor necrosis factor‐α by venom metalloproteinases: A hypothesis explaining local tissue damage following snake bite
Authors: Moura‐da‐Silva Ana Maria , Laing Gavin David , Paine Mark John Ingraham , Dennison Jeremy Michael Thomas Jonathan , Politi Vincenzo , Crampton Julian Moray , Theakston Robert David Geoffrey 
Published: March 2007

AbstractVenom‐induced necrosis is a common local debilitating sequela of bites by many vipers, frequently resulting in severe permanent scarring and deformity. Antivenoms are not effective under these circumstances unless administered within a few minutes of the bite; this is unlikely to occur in the rural tropics where most victims take a long time to reach medical care. We have shown that two venom zinc metalloproteinases (jararhagin from Bothrops jararaca venom and a metalloproteinase from Echis pyramidum leakeyi venom) successfully cleaved the recombinant glutathione‐S‐transferase – tumor necrosis factor‐α fusion protein (GST‐TNF‐α) substrate to form biologically active TNF‐α which was shown to be neutralized by ovine TNF‐α Fab antibodies. This resulted in a reduction of venom‐induced necrosis in mice when injected intravenously or intradermally both before and after intradermal injections of E.p.leakeyi venom. A peptidomimetic (POL 647) was also found to inhibit the Echis metalloproteinase, thus preventing the processing of the TNF precursor; this was shown using a TNF‐α‐sensitive cell culture assay and electrophoresis. These observations demonstrate the possible importance of TNF‐α in the development of the resulting necrotic lesion and leads to the hypothesis that increased levels of venom metalloproteinases following snake bite release active TNF‐α. This cytokine may contribute to the local necrosis and also induce the production of endogenous matrix metalloproteinases, which in turn generate a positive feedback mechanism resulting in continued cleavage of pro‐TNF‐α. The results indicate that inhibition or neutralization of endogenous TNF‐α appears to result in a significant reduction in venom‐induced necrosis. This could help to explain the clinical observations that treatment of local necrosis following snake bite by antivenom is only minimally successful.
The interleukin‐8 receptor B and CXC chemokines can mediate transendothelial migration of human skin homing T cells
Authors: Babi Luis F. Santamaria , Moser Bernhard , Soler Maria Teresa Perez , Moser René , Loetscher Pius , Villiger Beat , Blaser Kurt , Hauser Conrad 
Published: March 2007

AbstractWe studied the involvement of chemokines that bind to G protein‐coupled receptors in the migration of skin homing T cells across a bilayer vascular construct (BVC) consisting of a fibroblast matrix underneath an activated endothelial (EC) monolayer. Based on the expression of the cutaneous lymphocyte‐associated antigen (CLA), a skin homing receptor, CD45R0+ T cells freshly isolated from blood or HUT‐78 cutaneous T lymphoma cells were separated into CLA+ and CLA− subpopulations. These T cells were incubated on interleukin (IL)‐1β and tumor necrosis factor‐α‐activated EC, and the number of transmigrated cells was determined. The chemokine IL‐8 was selectively involved in the enhanced migration of CLA+ T cells across activated EC as demonstrated by blocking antibody to IL‐8 but not to GRO‐α, MCP‐1 and RANTES. Identical results were obtained with both human umbilical vein EC (HUVEC) and microvascular skin EC (HDMEC). Pertussis toxin selectively inhibited the enhanced transendothelial migration (TEM) of CLA+ T cells, suggesting that CLA‐dependent TEM depends on Gi protein‐transmitted signals. Moreover, the IL‐8 receptor B (IL‐8RB) appeared to be functionally involved in TEM, as demonstrated by receptor desensitization with the CXC chemokines IL‐8 and GRO‐α and by blocking the IL‐8RB with specific monoclonal antibodies. Although only the IL‐8RB was involved in CLA‐dependent TEM, mRNA encoding IL‐8RA and IL‐8RB was expressed by both CLA+ and CLA− T cells. This correlated with IL‐8RA and IL‐8RB surface expression on these cells. Thus, the IL‐8RB is selectively functional in TEM of T cells expressing the skin homing receptor CLA. Our results demonstrate a critical role for IL‐8 and possibly other IL‐8RB ligands in addition to the IL‐8RB in TEM and suggest the involvement of these molecules in the homing of specific T cells to inflamed skin.