bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antigen processing for presentation by class II major histocompatibility complex requires cleavage by cathepsin E
Authors: Bennett Karen , Levine Timothy , Ellis Joanna S. , Peanasky Robert J. , Michael Samloff I. , Kay John , Chain Benjamin M. 
Published: March 2007

AbstractProteolytic degradation (processing) of antigen by antigen‐presenting cells is a major regulatory step in the activation of a T lymphocyte immune response. However, the enzymes responsible for antigen processing remain largely undefined. In this study we show that cathepsin E, and not the ubiquitous lysosomal cathepsin D, is the major aspartic proteinase in a murine antigen‐presenting cell line, A20. Thisenzyme is localized to a non‐lysosomal compartment of the endosomal system in these cells. Functional studies using a highly specific inhibitor of cathepsin E show that this enzyme is essential for the processing of ovalbumin by this cell line. Thus, cathepsin E, whose function was hitherto unknown, may play a major role in antigen processing.
Cloning and sequencing of the cDNA encoding the human homologue of the murine immunoglobulin‐associated protein B29
Authors: Müller Brigitte , Cooper Laura , Terhorst Cox 
Published: March 2007

AbstractMembrane‐bound immunoglobulins (Ig) on the surface of murine B cells are noncovalently associated with a heterodimeric protein complex of MB‐1 and B29 (alsocalled Ig‐α and Ig‐β). The Ig‐associated proteins are predicted to regulate the assembly and transport of the Ig complex tothe cell surface and to couple membrane‐bound Ig to intracellular signal transduction pathways. Wehave isolated and sequenced a full‐length cDNA clone encoding the human homologue of the B29 protein. The predicted amino acid sequence was compared to its murine counterpart, to MB‐1 and to the human T cell receptor (TcR)‐associated CD3 proteins. The alignment of the human B29 protein with its murine counterpart revealed 90%homology in the C‐terminal portion comprisingthe cytoplasmic tails, the transmembrane regions and the adjacent 26 amino acids of the extracellular regions. Only 59% homology was found in the rest of the Ig‐like extracellular domains. The high degree of conservation observed for the C‐terminal amino acids suggested that thesedomains of the proteins play important functional roles for the Ig complex. Indicative of this was the conservation of the antigen receptor tail motif D‐(X)7−E/D‐(X)2−Y‐(X)2−L‐(X)7−Y‐(X)2−L/I which is thought to be a component of signal transduction pathways. This motif is also found in the human and murine MB‐1 proteins as well as in the TcR‐associated CD3 molecules. Further regions of homologybetween B29, MB‐1 and the CD3 proteins included extracellular residues which were predicted to maintain the Ig‐like structure, and hydrophilic residues within the transmembrane regions which may be utilized during the intracellular assembly and transport of the oligomeric Ig/MB‐1/B29 or TcR/CD3 complexes. Thus the similarities found between B29, MB‐1 and the CD3 proteins suggest conserved functions for both the Ig‐ and TcR‐associated proteins.
A viral peptide can mimic an endogenous peptide for allorecognition of a major histocompatibility complex class I product
Authors: Guimezanes Annick , Schumacher Ton N. M. , Ploegh Hidde L. , Schmitt‐Verhulst Anne‐Marie 
Published: March 2007

AbstractAlloreactive class I‐restricted T cells may recognize the class I structure alone, in association with a specific peptide, or with any stabilizing peptide. We havetested the role of endogenous peptides in the recognition of H2Kb molecules by two alloreactive cytolytic T lymphocyte (CTL) clones using the mutanttumor lineRMA‐S, which expresses its surface H‐2b molecules devoid of peptides and is not lysed by these two CTL clones. Empty H‐2b molecules on RMA‐S cells can be stabilized by binding exogenously added peptides. H‐2Kb−specific recognition of the RMA‐S cells by one of the CTL clones was restored by endogenous peptide extracts which only minimally stabilized H2Kb on the surface of RMA‐S cells, indicating the requirement for a specific peptide on a limited number of H2Kb molecules. In addition, one out of three peptides which greatly enhance the expression of H2Kb, the nucleoprotein peptide 52–59 from vesicular stomatitis virus (VSV), was also able to restore the lysis of RMA‐S cells by the clone. The recognition of a common motif by an alloreactive clone (H‐2k anti‐H‐2Kb) and virus‐specific Kb−restricted clones suggests that both H‐2k and H‐2b thymic environments allow selection of T cells capable of recognizing H2Kb+VSV and that tolerance to self, as would be the case in the (H‐2k x H‐2b)F1 mice, would partially delete the repertoire of antiviral T cells.
Lipopolysaccharide induces up‐regulation of CD14 molecule on monocytes in human whole blood
Authors: Marchant Arnaud , Duchow Jochen , Delville Jean‐Pierre , Goldman Michel 
Published: March 2007

AbstractWe examined by flow cytometry the expression of lipopolysaccharide (LPS) receptor CD14 molecule on monocytes after addition of LPS to human whole blood. Within 30 min LPSinduced an increase in monocyte CD14 expression, peaking between 1 and 3 h andfollowedby a slow decrease. Maximal increase in anti‐CD14 monoclonal antibody binding sites was estimated as twofold the basal value. This effect, already observed with very low concentrations of LPS (10 pg/ml), was dose dependent. Protein synthesis was not involved in the CD14 hyperexpression since it was not influenced by co‐incubation with cycloheximide. Finally, LPS‐induced up‐regulation of monocyte CD14 wasassociated with an increased binding of fluoresceinated LPS. We conclude that LPS in whole blood up‐regulates the expression of its own CD14 receptor on monocytes, a phenomenon that could be relevant to the pathogenesis of gram‐negative sepsis.
A V region‐connected autoreactive subfraction of normal human serum immunoglobulin G
Authors: Dietrich Gilles , Kaveri Srinivas‐Venkatesh , Kazatchkine Michel D. 
Published: March 2007

AbstractMouse and human natural IgM autoantibodies have been shown to be polyreactive and “connected” through V region‐dependent interactions. In the present study, we have identified a connected subfraction of normal human serum IgG by using affinity chromatography of F(ab′)2 fragments of pooled IgG (IVIg) or of IgG from a single donor on Sepharose‐bound F(ab′)2 fragments of the same source of IgG. The connected fraction of IgG exhibited a high content of autoantibodies directed against a wide panel of evolutionarily conserved self antigens and of self antigens that may be targets of autoantibodies in autoimmune diseases. Connected IgG also contained higher amounts of antibodies directed against commonly encountered microbial antigens than unfractionated IgG. The connected fraction did not, however, differ from unchromatographed IgG nor from non‐connected IgG in its content of antibodies to vaccinal antigens and to distant foreign antigens. Thus, in humans as in mice, connectivity is a prominent feature of autoantibodies. Our observations are suggestive of a tight control by IgG of the expressed autoreactive repertoire in healthy individuals and strengthen the concept that the therapeutic infusion of pooled normal IgG (IVIg) may be effective in autoimmune diseases by bringing to patients normal regulatory components of the immunoglobulin network.
Analysis of immunoglobulin variable region genes from human IgG anti‐DNA hybridomas
Authors: Winkler Thomas H. , Fehr Holger , Kalden Joachim R. 
Published: March 2007

AbstractThe molecular mechanisms leading to anti‐double‐stranded (ds)DNA antibody production in systemic lupus erythematosus (SLE) are poorly understood. We describe here the immunoglobulin variable region genes of six human hybridomas secreting IgG anti‐dsDNA antibodies derived from three SLE patients. The monoclonal IgG anti‐dsDNA antibodies have been shown to be of high affinity and no multireactivity was observed (Winkler et al., Clin. Exp. Immunol., 1991. 85: 379). The comparison of the variable region genes expressed in the hybridomas with known germ‐line genes as well as with the germ‐line counterparts from one patient shows that the VH and VL sequences are somatically mutated. The pattern and extent of the observed somatic mutations are suggestive for an antigen‐driven selection of at least four of these B cell clones. Several VH and VL genes used by the hybridomas were found to be expressed in the natural antibody repertoire, in the restricted fetal repertoire and in B cell malignancies expressing the CD5 antigen.
Interleukin‐4‐mediated tumor suppression in nude mice involves interferon‐γ
Authors: Platzer Cornelia , Richter Günther , Überla Klaus , Hock Hanno , Diamantstein Tibor , Blankenstein Thomas 
Published: March 2007

AbstractThe molecular events during the anti‐tumor response induced by interleukin (IL)‐4 were investigated by quantitative polymerase chain reaction. The growth of Chinese hamster ovary cells transfected to produce IL‐4 (CHO.T1) was strongly suppressed when cells were injected intraperitoneally into nude mice and this suppression was accompanied by the rapid accumulation of activated macro‐phages. Peritoneal cells from such mice were analyzed for mRNA induced by IL‐4. Correlating with a high local IL‐4 concentration, several transcripts were found to be up‐regulated during the early phase of the anti‐tumor response [IL‐4 receptor, IL‐5, tumor necrosis factor (TNF) and interferon (IFN)‐γ]. The functional relevance of the elevated mRNA levels was analyzed by injection of CHO.T1 cells together with anti‐cytokine monoclonal antibodies (mAb). In contrast to anti‐IL‐5 and anti‐TNF mAb, an anti‐IFN‐γ mAb interfered with the anti‐tumor response demonstrating the involvement of IFN‐γ during the IL‐4‐induced tumor suppression. Tumor growth in anti‐IFN‐γ mAb‐treated animals was significantly delayed in comparison to anti‐IL‐4 mAb‐treated mice, suggesting that IFN‐γ‐independent effector cells may also be involved.
GMP‐140 (P‐selectin/CD62) binds to chronically stimulated but not resting CD4+ T lymphocytes and regulates their production of proinflammatory cytokines
Authors: Damle Nitin K. , Klussman Kerry , Dietsch Mary T. , Aruffo Alejandro , Mohagheghpour Nahid 
Published: March 2007

AbstractGMP‐140 (P‐selectin), a 140‐kDa granular membrane glycoprotein localized to the α granules of platelets and the Weibel‐Palade bodies of endothelial cells, is thought to play an important role in adhesive interactions predominantly between granulocytes, platelets and vascular endothelial cells during inflammation. Although GMP‐140 binds to granulocytes, its binding to lymphocytes has not been demonstrated. Using genetically engineered IgG Cγ1 fusion protein of the extracellular domains of GMP‐140, we demonstrate that GMP‐140 binds to chronically antigen (Ag)‐stimulated CD4+ T cells. Freshly isolated CD4+ T cells did not bind GMP‐140, but priming and subsequent stimulation with alloantigen induced and gradually increased expression of GMP‐140‐reactive structures on their surface. T cells isolated from rheumatoid synovial fluids also exhibited strong binding to GMP‐140. The binding of GMP‐140 to primed T cells is not influenced by preactivation with phorbol 12‐myristate 13‐acetate, is almost completely abolished by pretreatment of T cells with neuraminidase or trypsin, and is also strongly inhibited by EDTA, the soluble sulfated glycans dextran sulfate, fucoidan, and heparin, but not by chondroitin sulfates. In spite of its strong binding to Ag‐primed T cells, GMP‐140 did not modulate the proliferative responses of these cells to various stimuli. However, GMP‐140 in conjunction with anti‐T cell receptor αβ monoclonal antibodies augmented the production of granulocyte‐macrophage colony‐stimulating factor GM‐CSF and inhibited the production of interleukin‐8 by Ag‐primed T cells without influencing their tumor necrosis factor‐α production. These results suggest that GMP‐140 binds to chronically stimulated CD4+ T cells and differentially modulates their production of proinflammatory cytokines. The ability of Ag‐primed T cells to bind GMP‐140 may facilitate interactions with activated platelets and endothelial cells affecting the course of inflammation.
Molecular basis for a severe case of leukocyte adhesion deficiency
Authors: Corbí Angel L. , Vara Alicia , Ursa Angeles , Rodriguez Mari Cruz García , Fontán Gumersindo , Sánchez‐Madrid Francisco 
Published: March 2007

AbstractThe leukocyte integrins LFA‐1, Mac‐1 and p150,95 (CD11a/CD18, CD11b/CD18, CD11c/CD18) mediate crucial leukocyte adhesive functions in immune and inflammatory reactions. Leukocyte adhesion deficiency (LAD) disease is caused by the defective expression of these adhesion molecules on leukocytes, and is characterized by recurrent infections and impaired pus formation due to the blockade of leukocyte migration into inflamed tissues. LAD is originated by heterogeneous mutations affecting the CD18 gene and, based on the severity of the deficiency, two phenotypes (severe and moderate) have been defined. Biochemical and genetic studies have allowed the classification of five different types of LAD. We have identified a type V LAD patient (severe phenotype, and normal size and levels of both CD18 precursor and CD18 mRNA), and determined its molecular basis. Reverse transcription‐polymerase chain reaction and cloning and sequencing of CD18 cDNA derived from this patient revealed three silent mutations and a missense mutation that leads to the substitution of glycine at position 169 for an arginine. Analysis of patient‐derived cDNA clones revealed the concomitant presence of aberrant splicing within the 5' region of the CD18 gene. The description of an identical mutation at residue 169 in an unrelated severe LAD patient raises the possibility that severe LAD type V is caused by a unique genetic defect.
Phenotypic characterization of KU812, a cell line identified as an immature human basophilic leukocyte
Authors: Blom Thomas , Huang Ranyang , Aveskogh Maria , Nilsson Kenneth , Hellman Lars 
Published: March 2007

AbstractThe knowledge about the differentiation of basophilic leukocytes is fragmentary. This report discusses a detailed phenotypic characterization of molecular markers for hematopoietic differentiation in a basophilic leukemia cell line, KU812. The expression of markers for lymphoid, erythroid, neutrophil, eosinophil, monocytic, megakaryocytic, mast cell and basophil differentiation was analyzed at the mRNA level by Northern blots in the KU812 cells, and for reference, in a panel of human cell lines representative of the different hematopoietic differentiation lineages. KU812 was found to express a number of mast cell and basophil‐related proteins, i.e. mast cell tryptase, mast cell carboxypeptidase A, high‐affinity immunoglobulin (IgE) receptor α and γ chains and the core protein for heparin and chondroitin sulphate synthesis. We found no expression of a number of monocyte/‐macrophage or neutrophil leukocyte markers except for lysozyme. From earlier studies, it has been shown that lysozyme is not expressed in murine mucosal mast cell lines. This finding, together with the expression of the mast cell carboxypeptidase in KU812 might distunguish the phenotype of this cell line from that typical of mucosal mast cell lines in rodents. We found a low level of expression of the eosinophil and basophil marker, major basic protein, which might indicate a relationship between basophils and eosinophils. No expression is, however, detected with the eosinophil‐specific markers eosinophil cationic protein, eosinophil‐derived neurotoxin or eosinophil peroxidase.We also report an extensive screening for inducers of basophilic differentiation of the KU812 cells. The most efficient protocol of induction included serum starvation which led to a dramatic increase in a number of markers specific for mast cells and basophils such as tryptase, carboxypeptidase A and the heparin core protein.Finally, diisopropylfluorophosphate analysis of total protein extracts from KU812 show four labeled protein bands with sodium dodecyl sulfate‐polyacryl‐amide gel electrophoresis, indicating that this cell line expresses at least three previously undescribed serine proteases of which one or more could be a potential basophil‐specific marker(s).
Naturally occurring ABO antibodies: Long‐term stable, individually distinct anti‐A IgG spectrotypes
Authors: Rieben Robert , Frauenfelder Agnes , Nydegger Urs E. 
Published: March 2007

AbstractSpectrotypes of naturally occurring IgG antibodies to histo‐blood group substance A were analyzed by isoelectric focusing and a newly developed, non‐radioactive affinity immunoblotting assay. Specificity was tested by preabsorption of sera on red blood cells and on four different types of blood group substance A. Clonotype‐banding patterns of sera from 18 different blood donors were individually distinct, most of them showing an oligoclonal pattern with less than 15 visible bands. To analyze the influence of IgG subclass composition on spectrotype patterns, IgG subclasses were measured by ABO enzyme‐linked immunosorbent assay (ELISA) and were shown to be mostly IgG1 and IgG2. Anti‐A IgG1 spectrotypes could be detected with four sera and were also individually distinct. A series of six and seven serum samples, respectively, from two donors was used to analyze the time‐related changes of anti‐A IgG spectrotypes. Banding pattern of both individuals remained stable during the whole observation period of 167 and 82 days, respectively, and no differences between follow‐up samples could be detected. This long‐term stability of individual anti‐A IgG spectrotypes is backed by constant serum levels of anti‐A IgG and ‐IgM antibodies during the observation period as measured by ABO ELISA.
Altered patterns of T cell migration through lymph nodes and skin following antigen challenge
Authors: Mackay Charles R. , Marston Wendy , Dudler Lisbeth 
Published: March 2007

AbstractAntigen challenge has profound effects on a regional lymph node (LN); it leads to an increase in blood flow to the node, and a marked increase in lymphocyte output through the efferent lymphatics. We used the isolated LN model developed in the sheep to see if antigen challenge in a LN resembled inflammation in peripheral tissues. Following stimulation with an antigen (purified protein derivative of tuberculin), lymphocyte output from the LN showed the typical periods of “lymphocyte shutdown” and “recruitment”. The shutdown phase, when cell numbers in efferent lymph dropped by ∼80%, affected almost exclusively the naive‐type (adhesion10, L‐selectin+) T cell population. The large increase in T cell traffic through the node during the recuitment phase was mostly due to CD4+ memory‐type T cells and, moreover, the majority of these T cells were L‐selectin−, indicating that these cells were crossing from the blood by a molecular mechanism other than L‐selectin interaction with its ligand, the “lymph node vascular addressin” (MECA‐79). Examination of LN high endothelial venules revealed the presence of vascular cell adhesion molecule‐1 (VCAM‐1), an endothelial adhesion molecule which has been reported to bind preferentially memory‐type T cells in inflammatory lesions. Within the skin, antigen challenge also induced the rapid expression of VCAM‐1 on vascular endothelium. It was purely memory‐type T cells (β1−, L‐selectin+/−) that collected in lymph draining from this tissue. However within chronically inflamed skin, the MECA‐79 determinant appeared on vascular endothelium, and a small proportion of T cells draining from chronically inflamed skin were of naive‐type. The present results illustrate that there are similarities in the cellular and molecular events that characterize antigen stimulation of a LN and inflammation in a peripheral tissue.
Immunosuppression induced by nitric oxide and its inhibition by interleukin‐4
Authors: Al‐Ramadi Basel K. , Meissler Joseph J. , Huang Duan , Eisenstein Toby K. 
Published: March 2007

AbstractMice immunized with attenuated Salmonella typhimurium, strain SL3235, while protected against virulent challenge, are unable to mount in vivo and in vitro antibody responses to non‐Salmonella antigens, such as tetanus toxoid and sheep red blood cells, and exhibit profoundly suppressed responses to B and T cell mitogens. Suppression of antibody responses is mediated by macrophage (Mϕ)‐released soluble factors, and is completely reversed by treatment with interleukin (IL)‐4. The present report identifies the suppressor factor as nitric oxide (NO), and provides evidence for a mechanism by which IL‐4 abrogates suppression. Suppressed antibody responses correlated with high levels of NO secretion by splenocytes of SL3235‐immunized mice. NO production was observed only in cultures consisting of the adherent cell fraction of immune splenocytes. Further, immunosuppression was reversed by NG‐monomethyl‐L‐arginine (NMLA), a competitive inhibitor of NO synthesis, and was completely blocked by the addition of excess L‐arginine. Treatment with IL‐4, or anti‐interferon (IFN)‐γ monoclonal antibody (mAb), also abrogated suppression. Optimal reversal of suppression was observed only when NMLA, IL‐4, or anti‐IFN‐γ mAb, was added at day 0 of the 5‐day plaque‐forming cell assay. Treatment with either IL‐4 or anti‐IFN‐γ mAb also lead to a sharp inhibition of NO production by immune spleen cells. Moreover, the addition of IL‐4 to splenic adherent Mϕ inhibited their ability to generate NO. Our data characterize an immunoregulatory pathway, involving IFN‐γ and NO, by which Mϕ mediate immunosuppression and identify IL‐4 as a potent inhibitor of this pathway.
Molecular cloning and exon‐intron mapping of the gene encoding human transmembrane secretory component (the poly‐Ig receptor)
Authors: Krajči Peter , Kvale Dag , Taskén Kjetil , Brandtzaeg Per 
Published: March 2007

AbstractSecretory component (SC or the poly‐Ig receptor) plays a crucial role in mucosal immunity by translocating polymeric IgA and IgM through secretory epithelial cells into external body fluids. Labeled restriction fragments from human SC cDNA were used to screen a human genomic leukocyte library. Three overlapping clones, spanning a total of 19 kb of the human SC gene, including 3 kb of the 5′ flanking region, were characterized. The putative TATA box candidate, preceded by a CAAT‐like box, was found 329 nucleotides upstream of the first exon. Altogether 11 exons covering the entire coding region were identified. The exon size ranged from 59 to 657 nucleotides and exon‐intron junctions followed known consensus sequences. Three of the five extracellular Ig‐related domains (D1, D4 and D5) were confined to one exon each (E3, E5 and E6), whereas D2 and D3 were encoded by the same exon (E4). The latter exon corresponds to that involved in alternate splicing of rabbit SC. The membrane‐spanning segment was confined to part of one exon (E8). The cytoplasmic tail was encoded by four exons (E8–E11), whose boundaries encompassed fairly well the structural determinants proposed to be responsible for intracellular sorting of SC in the rabbit. The polymorphic restriction site reported earlier for Pvu II was localized to the third intron.