bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for an active hydrophobic form of factor H that is able to induce secretion of interleukin 1‐β or by human monocytes
Authors: Iferroudjene Djedjiga , Schouft Marie‐Thérèse , Lemercier Claudie , Gilbert Danièle , Fontaine Marc 
Published: March 2007

AbstractWe studied the capacity of human factor H to promote the secretion of a lymphocyte‐activating factor (LAF) by human monocytes cultured under serum‐free conditions. Presence of LAF in the culture supernatants was assessed with the mouse thymocyte assay. Highly purified factor H alone had no effect on thymocyte proliferation. When monocytes were cultured with factor H for 24 h, a significant secretion of LAF was observed. The effect was dose dependent over a range of factor H concentrations from 1 to 15 μg/ml. Polymyxin B did not abrogate the capacity of factor H to induce LAF secretion. Adsorption of factor H preparations onto anti‐factor H‐Sepharose completely suppressed the phenomenon. Conversely, the activity was recovered in the acidic eluate. Furthermore, factor H subpopulation Φ2, that was able to bind to phenyl‐Sepharose, was a stronger inducer of LAF secretion by monocytes than the subpopulation Φ1 (which did not bind to phenyl‐Sepharose). Using a specific radioimmunoassay for interleukin 1‐β (IL 1β), we observed a good correlation between the LAF activity and the amount of IL 1β secreted by human monocytes stimulated with factor H.We have shown previously that factor H (Φ2) bound specifically on Raji cells whereas factor H (Φ1) did not. These results argue for the participation of the interaction of factor H with its receptor to stimulate the secretion of IL 1 by monocytes and that the Φ2 form of factor H is a ligand for the human factor H receptor.
Presence of CD4 and CD8 determinants on CD4−CD8− murine thymocytes: passive acquisition of CD8 accessory molecules
Authors: Shores Elizabeth W. , Sharrow Susan O. , Singer Alfred 
Published: March 2007

AbstractIn the present study we have examined the possibility that CD4 and CD8 accessory molecules can be passively acquired by thymocytes. We initially observed that most thymocytes contained within the CD4−CD8− subset actually possess low levels of CD4 and CD8 on their cell surface. However, the detection of CD4 and CD8 on CD4−CD8− cells was dependent on the presence of other CD4+/CD8+ thymocytes which were actively synthesizing CD4 and CD8. These initial findings suggested that the appearance of CD4/CD8 on “double‐negative” thymocytes was due to the passive acquisition of these accessory molecules from CD4+/CD8+ cells present within the thymus. To investigate this possibility directly, we made both in vivo and in vitro mixes of thymocytes possessing different alleles of CD8 (Ly‐2.1 and Ly‐2.2). Under these experimental conditions, we detected Ly‐2.2 on the surface of thymocytes that were genetically Ly‐2.1+ and incapable of synthesizing Ly‐2.2. These data indicate that thymocytes can express cell surface CD8 molecules which they have not produced but have acquired from other cells in their environment. Thus, the present study indicates that low‐level surface expression of cell surface CD4/CD8 differentiation molecules does not necessarily identify distinct thymocyte subpopulations.
Oligonucleotide primers for polymerase chain reaction amplification of human immunoglobulin variable genes and design of family‐specific oligonucleotide probes
Authors: Marks James D. , Tristem Michael , Karpas Abraham , Winter Greg 
Published: March 2007

AbstractIn recent work, the polymerase chain reaction (PCR) has been used to amplify rearranged mouse and human immunoglobulin heavy and χ light chain variable (V) genes. Here we have optimized the design of the PCR primers for human V genes and used them to amplify cDNA from human peripheral blood lymphocytes. Cloning and sequencing revealed a diverse repertoire of V genes, and the presence of members of each human V gene family. After alignment of the sequences, we identified a region conserved within V gene families, but differing between families, and used this to design family‐specific oligonucleotide probes.
Immune response to soluble exoantigens of Plasmodium falciparum may contribute to both pathogenesis and protection in clinical malaria: evidence from a longitudinal, prospective study of semi‐immune African children
Authors: Riley Eleanor M. , Jakobsen Palle Hoy , Allen Stephen J. , Wheeler Jeremy G. , Bennett Stephen , Jepsen Soren , Greenwood Brian M. 
Published: March 2007

AbstractSome soluble exoantigens of Plasmodium have lipopolysaccharide (LPS)‐like properties and are believed to contribute to the pathogenesis of acute malaria. We have studied cellular and humoral immune responses to several purified exoantigens of Plasmodium falciparum in a cohort of children and compared these responses with their subsequent susceptibility to malaria infection and clinical disease. We found no evidence that either lymphoproliferative or interferon‐γ (IFN‐γ) responses to these antigens were associated with protective immunity. On the contrary, children whose cells produced IFN‐γ after in vitro activation with one of the soluble antigens (Ag7) were more likely to experience clinical manifestations of malaria infection (fever and malaise) than were children whose cells did not produce IFN‐γ. It is possible that exoantigen‐induced IFN‐γ may exacerbate the LPS‐like effects of these antigens. However, serum antibodies to another antigen (Ag2) were more prevalent in children with asymptomatic infections or low parasitemia than in children with fever and higher parasitemia (confirmed clinical malaria), suggesting that these antibodies may contribute to the development of protective immunity.
The genes for a mouse hematopoietic differentiation marker called the heat‐stable antigen
Authors: Wenger Roland H. , Ayane Mohamed , Bose Ron , Köhler Georges , Nielsen Peter J. 
Published: March 2007

AbstractWe have isolated a murine cDNA by virtue of its expression in pre‐B cell lines but not in plasmacytomas. In mouse, mRNA is detected by Northern blot analysis exclusively in hematopoietic tissues with the exception of brain. When expressed in bacteria, the encoded protein is specifically recognized by several antibodies against the murine hematopoietic differentiation marker called heat‐stable antigen (HSA). In contrast to previous speculations, these results suggest that the antigenic determinant recognized by anti‐HSA antibodies is proteinaceous. The cDNA sequence is essentially identical to a mouse HSA cDNA recently published (Kay et al., J. Immunol. 1990. 145: 1952). Three HSA genes were isolated, one of which corresponds to the isolated cDNA. The other two appear to be intronless retroposons which, despite numerous sequence changes, maintain an open reading frame. One of these intronless genes could code for an alternative form of HSA with a transmembrane domain and a cytoplasmic tail not encoded by the intron‐containing gene. This gene could be expressed, based on sequence comparisons of the three genes. However, using polymerase chain reaction amplification of first strand cDNA from various cell lines and adult mouse tissues, we could detect expression only of the intron‐containing gene.
Synergistic effect of interleukin 1 and soluble CD23 on the growth of human CD4+ bone marrow‐derived T cells
Authors: Bertho Jean‐Marc , Fourcade Christine , Dalloul Ali H. , Debré Patrice , Mossalayi M. Djavad 
Published: March 2007

AbstractLow‐affinity Fcϵ receptor (FcϵRII/CD23) is expressed by various human cells and known to be cleaved into soluble fragments (sCD23). Several biological activities were ascribed to these molecules. In this study, we have assessed the effect of recombinant 25‐kDa sCD23 (rsCD23) on human bone marrow‐derived T cells. Our results show that rsCD23 in synergy with recombinant interleukin 1 enhances mitogenic responsiveness of CD4+ T cells but does not affect CD8+ cell growth. Furthermore, rsCD23 synergizes autologous marrow cells in enhancement of CD4+ cell growth while CD23 monoclonal antibodies decrease accessory cell effect. Together, these data confirm cytokine‐like activity of sCD23 on human T cell lineage.
CD2 is functionally linked to the ζ‐natural killer receptor complex
Authors: Vivier Eric , Morin Paul M. , O'Brienm Carmeline , Schlossman Stuart F. , Anderson Paul 
Published: March 2007

AbstractNatural killer (NK) cells express two distinct surface receptors capable of triggering cytolytic effector function. The first is CD 16, an immunoglobulin Fc receptor that allows NK cells to mediate antibody‐dependent killing (ADCC). NK cells express CD16 in association with ζ, a signal‐transducing subunit that is also a component of the T cell receptor complex. Activation of NK cells via CD16 results in tyrosine phosphorylation of ζ. The second NK cell triggering receptor is CD2, a 50–55‐kDa cell surface molecule that is also expressed on T cells. Here we show that NK cell activation induced by mAb reactive with CD2 (either anti‐T11.1 alone or with anti‐T11.2 in combination) also results in the tyrosine phosphorylation of ζ. Our results indicate that CD2 is functionally linked to the CD16‐ζ complex and suggest that the ζ subunit plays a central role in the signal transduction pathways utilized by NK cells.
Adhesion receptors involved in clustering of blood dendritic cells and T lymphocytes
Authors: Scheeren Robert A. , Koopman Gerrit , van der Baan Sieberen , Meijer Chris J. L. M. , Pals Steven T. 
Published: March 2007

AbstractThe relationship of dendritic cells (DC) isolated from the peripheral blood to those of lymphoid tissue is, in terms of maturation and function, incompletely understood. In our present study, we have explored the molecular basis of adhesion of T cells to blood DC. Analysis of the expression of adhesion receptors on the cell surface of blood DC revealed that these cells express lymphocyte function‐associated antigen (LFA)‐1 (CD11a/18), ICAM‐1 (CD54), LFA‐3 (CD58) and CD44, but are very late antigen (VLA)‐4 (CD49d) and vascular cell‐adhesion molecule (VCAM)‐1 negative. The LFA‐1 pathway was found to play a key role in T cells‐blood DC adhesion; monoclonal antibodies (mAb) against both LFA‐1 and ICAM‐1 strongly inhibited adhesion between those cells. Moreover, a T cell clone from an LFA‐1‐deficient patient showed poor binding to blood DC. The important role of LFA‐1 in T cell‐blood DC adhesion was also supported by the metabolic energy and divalent cation dependence of the interaction. mAb against LFA‐3 and CD2 did not inhibit T cell‐blood DC binding. In contrast to the strong inhibition by antibodies to LFA‐1 and ICAM‐1, antibodies to CD44 enhanced conjugate formation between T cells and blood DC. Together, our results show that the LFA‐1/ICAM‐1 pathway plays a central role in T cell‐blood DC adhesion, a situation like that in T cell adhesion to lymphoid DC. However, unlike lymphoid DC, blood DC do not express VCAM‐1 nor use LFA‐3 for T cell binding.
Antibody specificity and immunoglobulin VH utilization of human monoclonal CD5+ B cell lines
Authors: Schutte Mieke E. M. , Ebeling Saskia B. , Akkermans Karine E. , Gmelig‐Meyling Frits H. J. , Logtenberg Ton 
Published: March 2007

AbstractHuman B lymphocytes that bear the CD5 antigen are relatively abundant in early ontogeny and comprise a small fraction of the B cell population in adults. The CD5 B cell subset has attracted much attention because of its possible involvement in autoimmune disease and certain B cell malignancies. To begin to understand the role of CD5 B cells in disease processes, we have generated a panel of ten human monoclonal B cell lines selected for expression of the CD5 antigen. These cell lines were obtained by Epstein‐Barr virus transformation of B lymphocytes isolated from the spleen, liver and bone marrow of a 19‐week‐old fetus, from cord blood and from peripheral blood of healthy volunteers. In addition, one cell line was isolated from the spleen of a patient with chronic lymphocytic leukemia. Here, we describe the antibody and immunoglobulin VH gene repertoire of this panel of CD5 B cell lines. The results of these experiments show that (a) some but not all CD5 B cell lines secrete polyreactive antibodies that bind to a variety of self‐ and xenoantigens and (b) members of the small VH4, VH5 and VH6 gene families are overrepresented in this panel of cell lines. Nucleotide sequence analysis revealed the expression of VH gene elements that have been previously reported in the preimmune B cell repertoire, in CD5 B cell tumors and in polyreactive antibodies.
Antigen‐induced inhibition of autoimmune response to rat male accessory glands: distinct characteristics of I‐A‐ and I‐E‐positive peritoneal cells
Authors: Rivero Virginia Elena , Ferro Maria Elena , Romero‐Piffiguer Marta , Correa Silvia , Yranzo‐Volonté Nora , Riera Clelia Maria 
Published: March 2007

AbstractThe present report describes different aspects of two populations of peritoneal cells (PC) obtained from rats injected i.p. 2 h or 24 h previously with a suppressor dose of a purified fraction (FI) of rat male accessory glands (RAG) (FI‐PC2h and FI‐PC24h, respectively). The FI‐PC2h, which are mainly I‐E (OX17) positive and can suppress the autoimmune response to RAG autoantigens, have an elevated phagocytic activity against Candida albicans and capacity to reduce the dye nitroblue tetrazolium. In contrast, FI‐PC24h, which are mainly I‐A (OX6) positive and can potentiate the autoimmunity to RAG autoantigens, have a diminished capacity to reduce the dye and a diminished phagocytic activity. Moreover, the Toxoplasma gondii appear to have a different effect on both populations. The parasites can invade FI‐PC2h while FI‐PC24h offer resistance to T. gondii aggression.FI‐PC2h cultured during 22 h (FI‐PC2‐24h in vitro), or PC obtained from syngeneic recipients injected i.p. 22 h previously with FI‐PC2h (FI‐PC2‐24h in vivo) show, as FI‐PC2h, an increase of the I‐E+ cells and capacity to induce suppression of the delayed‐type hypersensitivity response to RAG autoantigens when they are injected to syngeneic rats 10 and 3 days prior to the immunization with chemically modified (diazotized arsanilic and sulfanilic acid) RAG in complete Freund's adjuvant.The PC obtained 24 h after injection of irradiated rats with N‐PC plus FI show an increase of I‐E+ cells whereas an enhancement of I‐A+ cells can be observed when the PC are obtained 24 h after injection of irradiated and bone marrow‐reconstituted rats with N‐PC plus FI.These findings appear to indicate that FI‐PC2h and FI‐PC24h are functionally different and that the population obtained 24 h after injection of FI of RAG could not originate from either the population present 2 h after injection of FI of RAG injection nor from normal PC. They appear to require bone marrow precursors.
Identification and characterization of a protective immunodominant B cell epitope of pertactin (P.69) from Bordetella pertussis
Authors: Charles Ian G. , Li Jingli , Roberts Mark , Beesley Katrina , Romanos Mike , Pickard Derek J. , Francis Mike , Campbell Dick , Dougan Gordon , Brennan Michael J. , Manclark Charles R. , Jensen Maria Au , Heron Ivor , Chubb Ann , Novotny Pavel , Fairweather Neil F. 
Published: March 2007

AbstractEpitopes defined by monoclonal antibodies (mAb) specific for the Bordetella pertussis outer membrane protein P.69 (pertactin) were mapped using a series of amino‐ and carboxy‐terminal deletion mutants expressed in Escherichia coli. mAb were found to bind predominantly to a region of pertactin spanning a (Pro‐Gln‐Pro)5 repeat motif and one mAb was found to bind to another region spanning a (Gly‐Gly‐Xaa‐Xaa‐Pro)5 repeat motif. To localize further the mAb‐binding sites, a panel of synthetic peptides, a series of 94 overlapping hexameric peptides, and a P.69 30‐amino acid fusion to a hepatitis B core protein (HBcAg‐69), were synthesized. This combined approach has identified the binding site for the mAb BBO5: Pro‐Gly‐Pro‐Gln‐Pro‐Pro; mAb BBO7, E4A8 and E4D7: Ala‐Pro‐Gln‐Pro‐Pro‐Ala‐Gly‐Arg; and mAb BPE3: Thr‐Leu‐Trp‐Tyr‐Ala‐Glu‐Ser‐Asn‐Ala‐Leu‐Ser‐Lys‐Arg. We have used a non‐lethal murine respiratory model of B. pertussis infection to investigate the ability of a peptide containing the epitope of the mAb BBO5 to elicit protective immunity. Immunization of mice with the HBcAg‐69 protein prevented growth of B. pertussis in the lungs compared to mice receiving HBcAg alone, and protection correlated with high titers of anti‐P.69 antibodies.
Biochemical properties of MHC class II molecules endogenously synthesized and expressed by mouse Langerhans cells
Authors: Becker Detlef , Reske‐Kunz Angelika B. , Knop Jürgen , Reske Konrad 
Published: March 2007

AbstractThe cell surface expression and biosynthesis of Langerhans cells (LC)‐derived major histocompatibility complex (MHC) class II molecules from epidermal cells (EC) prepared freshly and cultured for up to 3 days was investigated. Based on the constitutive expression of MHC class II determinants by LC, a panning and magnetic bead selection procedure was employed, yielding 65% and 86% of I‐A+ cells, respectively. Phenotypical and cytochemical examinations revealed that the two LC preparations were free of contaminating macrophages as well as B and T cells. Freshly prepared enriched LC were highly efficient in the stimulation of protein antigen‐specific T cell clones, while LC purified from short‐term cultured EC suspensions proved to be more efficient allogeneic stimulator cells than fresh LC. Comparative analysis of LC obtained from freshly prepared and from short‐term‐cultured EC preparations indicated an up‐regulation of MHC class II determinants during short‐term culture. Radioiodination analysis of LC selected by magnetic beads demonstrated prominent class II α and β chain signals with only a minute fraction of invariant chains p35 and p45 being expressed at the cell surface. Unlike class II complexes derived from B cells, those from LC contained invariant chain fragment p20 in association with α/β heterodimers at the plasma membrane. No qualitative differences between freshly isolated and 3‐day cultured LC in cell surface expressed MHC class II components were detectable. Metabolic labeling with subsequent two‐dimensional electrophoresis revealed distinct features of LC‐derived MHC class II molecules with a high proportion of invariant chains in particular γ and p40 and their extensive sialylation. While fresh and 1‐day cultured LC exhibited appreciable levels of newly synthesized class II molecules, a dramatic down‐regulation in class II and invariant chain synthesis was measured after 3 days of continuous in vitro culture.
Human major histocompatibility complex class II‐negative colon carcinoma cells present staphylococcal superantigens to cytotoxic T lymphocytes: evidence for a novel enterotoxin receptor
Authors: Dohlsten Mikael , Hedlund Gunnar , Segren Sverker , Lando Peter A. , Herrmann Thomas , Kelly Adrian P. , Kalland Terje 
Published: March 2007

AbstractThe staphylococcal enterotoxins (SE) bind to major histocompatibility complex (MHC) class II molecules on target cells and activate T cells expressing particular T cell receptor Vβ sequences. In this report we demonstrate that SE bind to the MHC class II− SW620, Colo320DM and WiDr human colon carcinoma cell lines and direct cytotoxic T lymphocytes (CTL) to mediate strong target cell killing. Flow cytometry analysis, immunoprecipitation and Northern blotting experiments failed to demonstrate any surface expression of HLA‐DR, HLA‐DP and HLA‐DQ isotypes on the SW620 colon carcinoma cell line, whereas abundant expression of these isotypes was seen on Raji cells. SEB and SEC1 were efficiently presented at picomolar concentration by the MHC class II− colon carcinoma cells and MHC class II+ Raji cells, whereas SEA and SED were preferentially presented on the MHC class II+ Raji cells. An anti‐HLA‐DR monoclonal antibody inhibited SEB‐induced CTL targeting to Raji, but did not influence the killing of SW620 cells. Our data suggests the existence of functionally active SE‐binding structures on human colon carcinoma cells which are distinct from the conventional MHC class II molecules. The possibility that these putative new SE receptors play a role in the enterotoxin action of SE must be considered.
Sequences of the mouse F protein alleles and identification of a T cell epitope
Authors: Schofield J. Paul , Vijayakumar R. K. , Oliveira David B. G. 
Published: March 2007

AbstractF protein is found predominantly in the liver and is of unknown function. The protein has been of interest to immunologists in the areas of self tolerance and the immunogenetics of the anti‐F protein response. In the mouse there are two alleles (F1 and F2), and although mice are completely tolerant to the self form of the protein, mice of responder strains make a good antibody response to immunization with the non‐self form. This response cross‐reacts with the self form, implying firstly, that autoreactive B cells are present and that tolerance is therefore maintained at the T cell level, and secondly, that the difference between the two allelic products defines a T cell epitope.Primers based on the published sequence for rat F protein were used in the polymerase chain reaction to amplify the cDNA for the two mouse alleles. Subsequent sequencing shows a high degree of sequence identity between the rat and mouse cDNA. The two mouse cDNA are identical apart from a single A to G base change which predicts an asparagine (F1 protein) to aspartate (F2 protein) amino acid residue change. Using allele‐specific oligonucleotide probes we confirmed that this base change has the same strain distribution as the previously determined F protein type. Isoelectric focusing shows that F1 protein migrates in a more basic position than F2 protein, as predicted by the asparagine to aspartate change. Finally, a synthetic peptide from the allovariable site of F2 protein will successfully restimulate T cells in vitro from an F1 type mouse primed in vivo with whole F2 protein, whereas the corresponding peptide from F1 protein will not. This is evidence that, as predicted, the allovariable site does indeed define a T cell epitope. Peptides covering the rest of the F2 protein molecule were not stimulatory.
Interleukins 1, 4 and 6 induce the colony formation of human bone marrow B lineage cells
Authors: McGinnes Kimberley , Paige Christopher J. 
Published: March 2007

AbstractAn agar‐based, B cell colony assay (McGinnes, K. et al., Blood 1990, 76: 896) has been used to study the influence of known cytokines on the growth of B lineage colonies initiated by cells from normal, human bone marrow samples. We demonstrate that a combination of interleukin (IL) 1, IL 4 and IL 6 act directly to promote the generation of plaque‐forming colonies. IL 6 was shown to act at a late stage of colony formation, which is consistent with its role in the induction of immunoglobulin secretion from mature B cells. In contrast, IL 1 and IL 4 were required at earlier stages in the formation of colonies containing cells which secrete immunoglobulin.