bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipidation of T helper sequences from hepatitis C virus core significantly enhances T‐cell activity in vitro
Authors: Langhans B. , Braunschweiger I. , Schweitzer S. , Jung G. , Inchauspé G. , Sauerbruch T. , Spengler U. 
Published: March 2003

SummarySuccessful elimination of the hepatitis C virus (HCV) during acute infection has been linked to strong HCV‐specific in vitro T‐cell proliferation, whereas T cells from patients with chronic hepatitis C respond only weakly to HCV antigens. Lipid‐coupled peptides are immunostimulants, which might provide a basis for novel therapeutic strategies against HCV. Therefore, in 20 patients with chronic hepatitis C, we studied whether tri‐palmitoyl‐S‐cysteine‐coupled peptides could modify in vitro T‐cell proliferation (by [3H]thymidine uptake) in response to virus core and NS4. The lipopeptides corresponded to five immunodominant T helper epitopes of HCV core. Contrary to unmodified peptides, the lipopeptides specifically enhanced [3H]thymidine uptake in response to HCV antigens but not to a non‐HCV related control antigen. They increased the frequency of responders (stimulation index, SI ≥ 4) to core (13/20 versus 2/20; p = 0·0008) and NS4 (20/20 versus 7/20; p < 0·0001) among our patients with chronic hepatitis C. This immunostimulatory effect was dose‐dependent, and was observed specifically with lipopeptides corresponding to the HCV epitopes. Our data demonstrate that the poor in vitro T‐cell proliferation of patients with chronic hepatitis C can be improved when T cells are co‐stimulated with HCV core‐derived T helper lipopeptides, while the same peptides in unlipidated form had no effects. Thus, lipopeptides corresponding to HCV T‐cell epitopes may offer novel immunomodulatory strategies against HCV.
Normal and abnormal secretion by haemopoietic cells
Authors: Stinchcombe Jane C. , Griffiths Gillian M. 
Published: March 2003

SummaryThe secretory lysosomes found in haemopoietic cells provide a very efficient mechanism for delivering the effector proteins of many immune cells in response to antigen recognition. Although secretion shows some similarities to the secretion of specialized granules in other secretory cell types, some aspects of secretory lysosome release appear to be unique to melanocytes and cells of the haemopoietic lineage. Mast cells and platelets have provided excellent models for studying secretion, but recent advances in characterizing the immunological synapse allow a very fine dissection of the secretory process in T lymphocytes. These studies show that secretory lysosomes are secreted from the centre of the talin ring at the synapse. Proper secretion requires a series of Rab and cytoskeletal elements which play critical roles in the specialized secretion of lysosomes in haemopoietic cells.
Inhibition of the function of the FcγRIIB by a monoclonal antibody to thymic shared antigen‐1, a Ly‐6 family antigen
Authors: Ding Linna , Shevach Ethan M. 
Published: March 2003

SummaryThymic shared antigen‐1 (TSA‐1) is a member of the Ly‐6 family of glycosyl‐phosphatidylinositol (GPI)‐linked proteins. While it has been proposed that TSA‐1 may play a role in thymic development, a physiological ligand for this antigen has not been identified. Here we report that a monoclonal antibody (mAb) to TSA‐1, generated by immunizing a hamster with CD40 ligand (CD40L)‐activated B cells, interferes with the function of FcγRIIB on splenic B cells and the B‐cell lymphoma cell line, M12, by binding to TSA on the same cells. The interaction of anti‐TSA with FcγRIIB resulted in an inhibition of the ability of the FcγRIIB to cross‐link and/or aggregate soluble anti‐CD3 or soluble anti‐Cβ T‐cell receptor (TCR), leading to an inhibition of induction of expression of CD25 and CD69, interleukin (IL)‐2 production and proliferation of naive T cells. Cross‐blocking studies with mAbs strongly suggested that a physical association exists between TSA‐1 and the FcγRIIB on the surface of activated B cells and favour the view that a functional intermolecular association exists between these two distinct membrane antigens.
Requirements for autoimmune responses to mouse gastric autoantigens
Authors: Scarff Katrina L. , Judd Louise M. , Wilson Wendy E. , Laurie Karen L. , Toh Ban‐Hock , Gleeson Paul A. , Van Driel Ian R. 
Published: March 2003

SummaryAutoimmune gastritis, in which the H+/K+‐ATPase of parietal cells is the major antigen, is one of the most common autoimmune diseases. Here we examined if specific properties of the H+/K+‐ATPase or parietal cells are involved in rendering them autoimmune targets. The model antigens β‐galactosidase and ovalbumin (OVA) were expressed in parietal cells of transgenic mice. On experimental induction of autoimmune gastritis by neonatal thymectomy, autoantibodies to β‐galactosidase developed in mice expressing β‐galactosidase in parietal cells, a response that was independent of either the response to the gastric H+/K+‐ATPase or gastric inflammation. In contrast, mice that expressed OVA in parietal cells did not exhibit an antibody response to OVA after thymectomy. However, increasing the frequency of anti‐OVA T lymphocytes in OVA‐expressing mice resulted in autoantibodies to OVA and gastritis. These studies indicate that parietal cells can present a variety of antigens to the immune system. Factors such as the identity and expression level of the autoantigen and the frequency of autoreactive T cells play a role in determining the prevalence and outcome of the particular immune response. In addition, as not all mice of a particular genotype displayed autoimmunity, random events are involved in determining the target of autoimmune recognition.
Infection of murine keratinocytes with herpes simplex virus type 1 induces the expression of interleukin‐10, but not interleukin‐1α or tumour necrosis factor‐α
Authors: Zak‐Prelich Malgorzata , Halliday Katrina E. , Walker Craig , Yates Catherine M. , Norval Mary , Mckenzie Roddie C. 
Published: March 2003

SummaryHerpes simplex virus (HSV) is known to possess several mechanisms whereby it can evade the normal host immune defences. In this study the expression of the immunosuppressive cytokine, interleukin (IL)‐10, was monitored following infection of a murine keratinocyte cell line (PAM‐212) and compared with the expression of two proinflammatory cytokines: IL‐1α and tumour necrosis factor (TNF)‐α. The PAM‐212 cells were infected at a multiplicity of 0·5 with a clinical isolate of HSV type 1, and the mRNA of the three cytokines was assessed by semiquantitative reverse transcription–polymerase chain reaction (RT–PCR) over the following 24 hr. By 12 hr postinfection the amount of IL‐10 mRNA had increased significantly to five‐fold greater than that found in uninfected cells (P < 0·01), and this elevated level was maintained until at least 24 hr postinfection. In contrast, IL‐1α and TNF‐α mRNAs were not significantly up‐regulated by the HSV infection. Immunostaining with an IL‐10 monoclonal antibody (mAb) revealed that cytoplasmic IL‐10 protein had increased by 6–12 hr postinfection. This quantity was further increased at 24 hr postinfection, when the viral cytopathic effect was apparent. Viral replication was necessary, but not sufficient on its own, for IL‐10 induction. Experiments with HSV mutants lacking functional transactivating factors suggested that the viral transactivating proteins ICP‐0 and VP‐16 may be necessary for HSV‐induced IL‐10 expression. Thus, the up‐regulation in the expression of IL‐10 mRNA and protein induced by HSV early in the infection of keratinocytes represents a specific response and may be part of the viral strategy to avoid local immune defence mechanisms in the skin.
Nitric oxide‐enhanced resistance to oral candidiasis
Authors: Elahi Shokrollah , Pang Gerald , Ashman Robert B. , Clancy Robert 
Published: March 2003

SummaryA murine model of oral candidiasis was used to show that nitric oxide (NO) is involved in host resistance to infection with Candida albicans in infection‐‘resistant’ BALB/c and infection‐‘prone’ DBA/2 mice. Following infection, increased NO production was detected in saliva. Postinfection samples of saliva inhibited the growth of yeast in vitro. Treatment with NG‐monomethyl‐l‐arginine (MMLA), an inhibitor of NO synthesis, led to reduced NO production, which correlated with an increase in C. albicans growth. Reduction in NO production following MMLA treatment correlated with an abrogation of interleukin‐4 (IL‐4), but not interferon‐γ (IFN‐γ), mRNA gene expression in regional lymph node cells. Down‐regulation of IL‐4 production was accompanied with an increase in IFN‐γ production in infection‐‘prone’ DBA/2 mice. There was a functional relationship between IL‐4 and NO production in that mice treated with anti‐IL‐4 monoclonal antibody showed a marked inhibition of NO production in saliva and in culture of cervical lymph node cells stimulated with C. albicans antigen. The results support previous conclusions that IL‐4 is associated with resistance to oral candidiasis and suggest that NO is involved in controlling colonization of the oral mucosal surface with C. albicans.
Lack of Shiga‐like toxin binding sites in germinal centres of mouse lymphoid tissues
Authors: Imai Yasuyuki , Fukui Takashi , Ikegaya Asano , Ishikawa Tomoyuki , Ono Yousuke , Kurohane Kohta 
Published: March 2003

SummaryB cells in germinal centres are known to express carbohydrate antigen CD77 in human lymphoid tissues. The CD77 antigen is specifically recognized by Shiga‐like toxins (SLTs) that are produced by enterohaemorrhagic Escherichia coli O157:H7. To determine whether the binding subunits of Shiga‐like toxin‐1 (SLT‐1B) could have adverse effects on the murine immune system when used as an immunogen, we investigated whether SLT‐1B could bind to germinal centres of mouse lymphoid tissues. Frozen sections of peripheral lymph nodes and Peyer's patches from immunized mice were tested for the presence of SLT‐1B‐binding sites by immunohistological methods. Germinal centres were not stained with SLT‐1B, while they were intensely stained with peanut agglutinin (PNA), another marker of germinal centres. On the other hand, SLT‐1B specifically bound to renal tubules and collecting ducts in frozen sections of mouse kidney. This is consistent with results from human tissues. We also demonstrated that B220/PNA double‐positive populations in lymph nodes from immunized mice exhibited only marginal staining with SLT‐1B. The present results suggest that SLTs would not impede germinal centre functions of the murine immune system.
Interactions formed by individually expressed TAP1 and TAP2 polypeptide subunits
Authors: Antoniou Antony N. , Ford Stuart , Pilley Elizabeth S. , Blake Neil , Powis Simon J. 
Published: March 2003

SummaryThe transporter associated with antigen processing (TAP) supplies peptides into the lumen of the endoplasmic reticulum (ER) for binding by major histocompatibility complex (MHC) class I molecules. TAP comprises two polypeptides, TAP1 and TAP2, each a ‘half‐transporter’ encoding a transmembrane domain and a nucleotide‐binding domain. Immunoprecipitation of rat TAP1 and TAP2 expressed individually in the human TAP‐deficient cell line, T2, revealed that both bound the endogenously expressed HLA‐A2 and ‐B51 class I molecules. Using HLA‐encoding recombinant vaccinia viruses HLA‐A*2501, ‐B*2704, ‐B*3501 and ‐B*4402, alleles also associated with both TAP1 and TAP2. Thus, TAP1 and TAP2 do not appear to differ in their ability to interact with MHC class I alleles. Single TAP polypeptide subunits also formed MHC class I peptide‐loading complexes, and their nucleotide‐binding domains retained the ability to interact with ATP, and may permit the release of peptide‐loaded MHC class I molecules in the absence of a peptide transport cycle. It is also demonstrated by chemical cross‐linking that TAP2, but not TAP1, has the ability to form a homodimer complex both in whole cells and in detergent lysates. Together these data indicate that single TAP polypeptide subunits possess many of the features of the TAP heterodimer, demonstrating them to be useful models in the study of ATP‐binding cassette (ABC) transporters.
Host responses to Renibacterium salmoninarum and specific components of the pathogen reveal the mechanisms of immune suppression and activation
Authors: Grayson T. Hilton , Cooper Lynne F. , Wrathmell Annette B. , Evenden Janet Roper, Andrew J. , Gilpin Martyn L. 
Published: March 2003

SummaryDuring infection, Renibacterium salmoninarum survives within the pronephric macrophages of salmonid fish. Therefore, to study the initial phases of the interaction we infected macrophages with live bacteria and analysed the responses of host and pathogen. It was found that the expression of msa encoding the p57 antigen of R. salmoninarum, was constitutive, while the expression of hly and rsh, encoding haemolysins, and lysB and grp was reduced after infection. Macrophages showed a rapid inflammatory response in which the expression of interleukin‐1β (IL‐1β), major histocompatibility complex class II (MHC II), inducible cyclo‐oxygenase (Cox‐2), and inducible nitric oxide synthase (iNOS) was enhanced, but tumour necrosis factor‐α (TNF‐α) expression was greatly reduced initially and then increased. After 5 days, except for TNF‐α and MHC II, expression returned to levels approaching those of uninfected macrophages. We propose that R. salmoninarum survives initial contact with macrophages by avoiding and/or interfering with TNF‐α‐dependent killing pathways. The effects of specific R. salmoninarum components were studied in vivo by injecting fish with DNA vaccine constructs expressing msa, hly, rsh, lysB, or grp. We found that msa reduced the expression of IL‐1β, Cox‐2, and MHC II but stimulated TNF‐α while hly, rsh and grp stimulated MHC II but down‐regulated TNF‐α. Constructs expressing hly or lysB stimulated iNOS expression and additionally, lysB stimulated TNF‐α. The results show how p57 suppresses the host immune system and suggest that the immune mechanisms for the containment of R. salmoninarum infections rely on MHC II‐ and TNF‐α‐dependent pathways. Moreover, prolonged stimulation of TNF‐α may contribute to the chronic inflammatory pathology of bacterial kidney disease.
Characterization of guinea‐pig group 1 CD1 proteins
Authors: Hiromatsu Kenji , Dascher Christopher C. , Sugita Masahiko , Gingrich‐Baker Cindy , Behar Samuel M. , LeClair Kenneth P. , Brenner Michael B. , Porcelli Steven A. 
Published: March 2003

SummaryCD1 molecules are cell‐surface glycoproteins with strong structural similarities to major histocompatibility complex (MHC) class I molecules, and studies in humans and mice have demonstrated that CD1 proteins perform the unique role of presenting lipid antigens to T lymphocytes. Our previous studies have shown that guinea‐pigs, unlike the muroid rodents, have an extended family of group 1 CD1 genes. In the current study, we raised monoclonal anibodies (mAbs) against guinea‐pig CD1 proteins and generated transfected cell lines expressing individual members of the guinea‐pig CD1 family. Our results indicated that multiple members of the guinea‐pig CD1 family, including members that are homologous to the human CD1b and CD1c proteins, are expressed at the protein level in transfected cells and in specialized antigen‐presenting cells such as monocyte‐derived dendritic cells. In addition, CD1 proteins, especially guinea‐pig CD1b3, were expressed on a large number of B cells in the guinea‐pig, and CD1 expression appeared to be regulated by B‐cell maturation or differentiation. Interestingly, three different patterns of intracellular localization were observed for the various guinea‐pig CD1 isoforms, a finding that is reminiscent of the distinct patterns of intracellular localization that have been previously demonstrated for human CD1a, CD1b and CD1c. Taken together, these results provide further evidence for substantial similarities between the guinea‐pig and human CD1 systems, thus supporting the possibility that the guinea‐pig may offer significant advantages as an animal model for the study of the in vivo role of CD1 proteins in infectious and autoimmune diseases.
Effects of C‐reactive protein and pentosan polysulphate on human complement activation
Authors: Klegeris AndIs , Singh Edith A. , MCGeer Patrick L. 
Published: March 2003

SummaryComplement (C) activation is believed to play an adverse role in several chronic degenerative disease processes, including atherosclerosis, myocardial infarction and Alzheimer's disease. We developed several in vitro quantitative assays to evaluate processes which activate C in human serum, and to assess candidates which might block that activation. Binding of C‐reactive protein (CRP) to immobilized cell surfaces was used as a tissue‐based method of activation, while immunoglobulin G in solution was used as a surrogate antibody method. Activation was assessed by deposition of C fragments on fixed cell surfaces, or by capture of C5b‐9 from solution. We observed that several cell lines, including SH‐SY5Y, U‐937, THP‐1 and ECV304, bound CRP and activated C following attachment of cells to a plastic surface by means of air drying. Treatment of human neuroblastoma SH‐SY5Y cells with the reactive oxygen intermediates generated by xanthine (Xa) – xanthine oxidase (XaOx) prior to air drying or by hydrogen peroxide solutions after air drying, enhanced C activation, possibly through oxidation of the cell lipid membrane. Several C inhibitors were tested for their effectiveness in blocking these systems. Pentosan polysulphate (PPS), an orally active agent, blocked C activation in the same concentration range of 1–1000 µg/ml as heparin, dextran sulphate, compstatin and fucoidan. PPS may have practical application as a C inhibitor.
Tumour necrosis factor‐α is a fundamental cytokine in autoimmune thyroid disease induced by thyroglobulin and lipopolysaccharide in interleukin‐12 p40 deficient C57BL/6 mice
Authors: Zaccone Paola , Fehérvári Zoltán , Cooke Anne 
Published: March 2003

SummaryExperimental autoimmune thyroiditis (EAT) is inducible in mice by immunization with mouse thyroglobulin (mTg) together with adjuvant, either lipopolysaccharide (LPS) or complete Freund's adjuvant (CFA). The severity of the disease is dependent on the mouse strain and on the adjuvant used. We have previously shown that interleukin (IL)‐12 deficient C57BL/6 mice immunized with mTg and CFA develop a significantly less severe thyroid infiltration in comparison to wild type C57 BL/6 mice. This result indicated a pivotal role for IL‐12 in the development of thyroiditis induced with CFA and mTg. In the present study we demonstrate that IL‐12 deficiency does not impair EAT induction when LPS is used as adjuvant. We also demonstrate that peritoneal exudate cells from IL‐12‐deficient mice stimulated in vitro either with LPS or IL‐18 secrete high levels of tumour necrosis factor (TNF). Together the results emphasize the difference between the use of CFA and LPS in the induction of EAT, the importance of TNF‐α for the pathogenesis of LPS‐induced EAT, and also show the capacity of IL‐12‐deficient mice to develop a competent response to LPS.
Differential response of bovine monocyte‐derived macrophages and dendritic cells to infection with Salmonella typhimurium in a low‐dose model in vitro
Authors: Norimatsu Mari , Harris James , Chance Victoria , Dougan Gordon , Howard Christopher J. , Villarreal‐Ramos Bernardo 
Published: March 2003

SummaryExposing bovine dendritic cells (DC) and macrophages (MΦ) to Salmonella typhimurium at a ratio of 1 cell to 10 bacteria had a cytotoxic effect that was not evident with a ratio of 1000 cells to 1 bacterium. This lower dose was considered to mimic more closely the in vivo situation and a comparison was made with this model of the consequences of infection for MΦ and DC. DC infected with S. typhimurium up‐regulated cell surface expression of major histocompatibility class I (MHC‐I), MHC‐II, CD40, CD80 and CD86. In contrast, infected MΦ did not exhibit detectable changes in expression of cell surface molecules, except for a marginal increase in CD40. mRNA transcription for tumour necrosis factor‐α, interleukin (IL)‐1β, IL‐6 and inducible nitric oxide synthase was up‐regulated in both infected DC and infected MΦ, although mRNA transcription for granulocyte–macrophage colony‐stimulating factor and IL‐12p40 was up‐regulated only in infected DC and for IL‐10 was only in infected MΦ. Infected DC had an increased ability to stimulate both allogeneic and antigen‐specific T‐cell responses compared to non‐infected controls. In contrast, infected MΦ showed an increased ability to induce allogeneic responses but this was less than seen for DC and no enhancement of ability to induce antigen‐specific T cell responses was seen. Thus, in a low‐dose infection model that does not result in the cytotoxicity of a substantial percentage of antigen presenting cells, bovine MΦ and DC respond differently to infection with S. typhimurium and this could have important implications for the development of the immune response.
Immunomodulatory effects of cyclosporin A on human peripheral blood dendritic cell subsets
Authors: Tajima Kenichirou , Amakawa Ryuichi , Ito Tomoki , Miyaji Michihiko , Takebayashi Masashi , Fukuhara Shirou 
Published: March 2003

SummaryCyclosporin A (CsA) is a potent immuno‐suppressant and is approved for the treatment of various disease conditions. The molecular biological mechanism of CsA has been investigated intensively in T cells and has been shown to involve the intracellular calcineurin pathway. Recently, it was reported that CsA has capacities to affect not only T cells but also antigen‐presenting cells such as B cells and dendritic cells (DCs). DCs are a master regulator of immune responses that have an integral capacity to prime naive T cells. In the present study, we investigated the biological effects of CsA on human peripheral blood DC subsets: CD11c+ myeloid and CD11c− lymphoid subsets. CsA inhibited the up‐regulation of co‐stimulatory molecules induced with or without microbial stimuli and CD40L on both CD11c+ and CD11c− subsets. In addition, CsA negatively regulated the endocytic activity of CD11c+ DC during the immature state. CsA inhibited the interleukin‐12 (IL‐12) production, but augmented the IL‐10 production from the LPS‐stimulated CD11c+ subset, whereas CsA reduced the interferon‐α (IFN‐α) production from the CD11c− subset infected with Sendai virus (SV). Both the LPS‐stimulated CD11c+ subset and SV‐infected CD11c− subset preferentially induced the development of IFN‐γ‐producing T helper‐type 1 (Th1) cells. Pretreatment of these DC subsets with CsA inhibited the Th1 skewing. These findings suggested a DC‐mediated mechanism of immunosupression by CsA.
Cloning and characterization of a cDNA encoding a male‐specific serum protein of the Mediterranean fruit fly, Ceratitis capitata, with sequence similarity to odourant–binding proteins
Authors: Thymlanou S. , Mavroidis M. , Kokolakis G. , Komitopoulou K. , Zacharopoulou A. , Mintzas A. C. 
Published: March 2003

AbstractMale‐specific serum proteins (MSSPs) are low molecular weight proteins which accumulate in high amounts in the haemolymph of adult males of the medfly Ceratitis capitata. By screening an expression library with anti‐MSSP antibodies, we have isolated and determined the nucleotide sequence of a cDNA clone coding for one of the male‐specific polypeptides (MSSP‐α). The MSSP‐α mRNA encodes a polypeptide of 144 amino acids with a secretory signal sequence of sixteen amino acids. Southern analysis indicated that there are multiple copies of MSSP genes in the medfly genome. Northern analysis showed that the MSSP mRNAs are synthesized only in adult males. The accumulation pattern of these mRNAs during development suggests that the expression of the MSSP genes is developmentally regulated at both transcriptional and translational levels. The predicted peptide sequence of MSSP‐α shows significant similarity to a group of pheromone‐ and general odourant‐binding proteins of insects.