bluuebunny/crossref_metadata_2025_split huggingface dataset:
Complement activation by apoptotic endothelial cells following hypoxia/reoxygenation
Authors: Mold C. , Morris C. A. 
Published: March 2003

SummaryReperfusion of ischaemic tissue initiates an inflammatory reaction that increases tissue injury. Complement activation at the endothelium contributes to this inflammation. This study investigated the mechanism of complement activation following reoxygenation of hypoxic human umbilical vein endothelial cells (HUVEC) as a model for complement activation observed on endothelium in reperfused ischaemic tissue. HUVEC cultured in 1% oxygen followed by reoxygenation activated the classical complement pathway resulting in C3 deposition. There was an increase in apoptotic cells in these cultures that was demonstrated by binding of fluorescein isothiocyanate‐Annexin V and staining for hypodiploid nuclei. To determine if apoptotic HUVEC activate complement, uniformly apoptotic cells were produced by serum and growth factor deprivation. These cells, but not the control HUVEC, activated the classical complement pathway in the absence of antibody or other serum factors. To determine if apoptotic cells in the reoxygenated cultures were activating complement, fluorescent analysis was done. Annexin V binding and C3d deposition on cells from reoxygenated cultures showed complete concordance on the subpopulation of apoptotic cells. In addition, complement activation following reoxygenation of HUVEC was eliminated by treatment of the cultures with a caspase inhibitor during reoxygenation. These results suggest that oxidative damage to endothelial cells during reoxygenation initiates apoptosis with exposure of phosphatidylserine. Apoptotic cells directly activate the classical pathway of complement by binding C1. Activation of complement at the endothelium may contribute to the inflammatory response as well as clearance and repair.
Integrating signals from T‐cell receptor and serum by T cells enhance translation of tumour necrosis factor‐α
Authors: Buxadé M. , Ramírez‐Alvarado M. , Fernández‐Troy N. , MacKenzie S. , Casaroli‐Marano R. P. , Vilella R. , Espel E. 
Published: March 2003

SummaryTumour necrosis factor‐α (TNF‐α) is a proinflammatory cytokine produced by several cell types, including T cells upon antigen stimulation. Its production is crucial for the development of an early defence against many pathogens, but its beneficial effects are dependent on the strength and duration of its expression. In this paper we present evidence indicating that serum increases translational efficiency of TNF‐α in human peripheral blood mononuclear cells stimulated with superantigen. The increase in translation of TNF‐α due to serum could be inhibited by the phosphatidylinositol (PI) 3‐K inhibitors, wortmannin and LY294002, suggesting that PI 3‐K is involved in the translational control of TNF‐α by serum. Similarly to primary T cells, stimulation of Jurkat T cells with superantigen led to TNF‐α secretion and this was up‐regulated by serum. Transfection of Jurkat cells with a constitutively active form of PI 3‐Kα increased the production of TNF‐α in cells stimulated with superantigen. Additionally, we used the specific inhibitors targeting ERK kinase and p38 mitogen‐activated protein kinase (MAPK), potentially downstream of PI 3‐kinase, PD98059 and SB203580. Differently from with PI 3‐K inhibitors, the accumulation of TNF‐α mRNA was inhibited by PD98059 or SB203580. These results suggest that, in T cells, activation of PI 3‐K is an important step in controlling TNF‐α protein synthesis in response to growth factors.
The role of the macrophage scavenger receptor in immune stimulation by bacterial DNA and synthetic oligonucleotides
Authors: Zhu Fu‐Gang , Reich Charles F. , Pisetsky David S. 
Published: March 2003

SummaryTo assess the role of the macrophage scavenger receptor type A (SRA) in immune activation by CpG DNA, cytokine induction and DNA uptake were tested in vitro and in vivo using SRA knockout (SRA−/−) and wild type (WT) mice. As a source of CpG DNA, Escherichia coli DNA (EC DNA) and a 20‐mer phosphorothioate oligodeoxynucleotide with two CpG motifs (CpG ODN) were used. In vitro, both EC DNA and the CpG ODN induced dose‐dependent increases of interleukin (IL)‐12 production by spleen cells and bone‐marrow‐derived macrophages (BMMΦ) from both SRA−/− and WT mice. The levels of cytokines produced by SRA−/− spleen cells and BMMΦ were similar to those of WT spleen cells and BMMΦ. When injected intravenously with CpG ODN and EC DNA, both SRA−/− and WT mice showed elevated serum levels of IL‐12. To investigate further the role of the SRA, flow cytometry and confocal microscopy were performed to examine the uptake of fluorescently labelled oligonucleotides. SRA−/− and WT BMMΦ showed similarity in the extent of uptake and distribution of oligonucleotides as assessed by these two techniques. Together, these findings indicate that, while the SRA may bind DNA, this receptor is not essential for the uptake of CpG DNA or its immunostimulatory activity.
Partial tolerance of subcutaneously transplanted xenogeneic tumour cell graft by Fas‐mediated immunosuppression
Authors: Sawada Takahiro , Koji Takehiko , Hishikawa Yoshitaka , Kishimoto Koji , Nagayasu Takeshi , Takahashi Takao , Oka Tadayuki , Ayabe Hiroyoshi 
Published: March 2003

SummaryCertain anti‐Fas antibodies, such as RMF2, induce apoptosis of Fas‐expressing cells. We applied the Fas/anti‐Fas system to induce killing of Fas‐expressing immunocytes with resultant immunosuppression. W7TM‐1 tumour cells, a rat T‐cell line, were inoculated subcutaneously in BALB/c mice and tumour growth was monitored in untreated mice and in mice treated with RMF2. Prior to treatment with RMF2, we examined the expression of Fas in isolated splenocytes and in tumour‐infiltrating lymphocytes by flow cytometry and immunohistochemistry, respectively. There was a remarkable increase in Fas‐positive lymphocytes, including natural killer (NK) cells, among splenocytes at day 5 after tumour cell inoculation. The number of Fas‐positive infiltrating lymphocytes also increased markedly, from day 5 to day 10. We then examined whether RMF2 could induce apoptosis of Fas‐positive activated lymphocytes isolated from the spleen at day 5 in vitro. Terminal deoxy (d) ‐UTP nick end labelling (TUNEL) and Annexin V staining methods showed apoptosis of isolated cells when incubated with RMF2, and typical apoptotic features were confirmed by 4′,6‐diamidino‐2‐phenylindole dihydrochloride (DAPI) staining. Furthermore, suppression of cellular and humoral immunity was noted in RMF2‐treated mice by mixed lymphocyte reaction and assay of serum levels of immunoglobulin G, respectively. Finally, treatment of animals with RMF2 daily from day 5 to day 9 could maintain the tumour size, while the tumour mass began to diminish in untreated mice immediately after reaching a maximum size. We confirmed the enhancing effects of long‐term treatment with RMF2, through the induction of immunosuppression, on the growth of unvascularized xenogeneic tumour cell grafts.
Refocusing of B‐cell responses following a single amino acid substitution in an antigen
Authors: Chiesa Marta Dalla , Martensen Pia M. , Simmons Cameron , Porakishvili Nino , Justesen Just , Dougan Gordon , Roitt Ivan M. , Delves Peter J. , Lund Torben 
Published: March 2003

SummaryIntranasal immunization of BALB/c strain mice was carried out using baculovirus‐derived human chorionic gonadotrophin (hCG) β‐chain, together with Escherichia coli heat‐labile enterotoxin. Gonadotrophin‐reactive immunoglobulin A (IgA) was induced in a remote mucosal site, the lung, in addition to a systemic IgG response. The extensive sequence homology with luteinizing hormone (LH) results in the production of LH cross‐reactive antibodies when holo‐hCG is used as an immunogen. In contrast to wild‐type hCGβ, a mutated hCGβ‐chain containing an arginine to glutamic acid substitution at position 68 did not induce the production of antibodies which cross‐react with LH. Furthermore, the epitopes utilized in the B‐cell response to the mutated hCGβ shifted away from the immunodominant region of the parent wild‐type molecule towards epitopes within the normally weakly immunogenic C terminus. This shift in epitope usage was also seen following intramuscular immunization of rabbits. Thus, a single amino acid change, which does not disrupt the overall structure of the molecule, refocuses the immune response away from a disadvantageous cross‐reactive epitope region and towards a normally weakly immunogenic but antigen‐unique area. Similar mutational strategies for epitope‐refocusing may be applicable to other vaccine candidate molecules.
Intraspecies heterogeneity of immunoglobulin α‐chain constant region genes in rhesus macaques
Authors: Scinicariello Franco , Attanasio Roberta 
Published: March 2003

SummaryImmunoglobulin A (IgA) is the major antibody class present in external secretions and is also an important component of serum immunoglobulins. On mucosal surfaces, IgA represents a first line of defence by neutralizing invading pathogens. The number of IgA constant‐region genes (Cα) present in different mammalian species is variable. Immunoglobulin Cα genes differ mainly in the sequences located in the hinge region. IgA molecules, whose hinge regions are remarkably similar to those of the respective human molecules, are present in hominoid primates. In this report, we show that two alleles of a single immunoglobulin Cα are present in rhesus macaques (Macaca mulatta). In addition, we show that intraspecies immunoglobulin Cα allelic polymorphism is very high in this non‐human primate species. Specifically, five different hinge regions, some of which are proline‐rich, were identified from a total of eight rhesus macaque immunoglobulin Cα‐chains. The five hinge regions were different from those present in hominoid primates, both in length and in sequence. These results represent the first example of high levels of intraspecies immunoglobulin constant‐region variability and suggest that IgAs of variable structure and function may be present in rhesus macaques. As rhesus macaques are widely used as animal models for the development of vaccines for acquired immune deficiency syndrome (AIDS), the possible presence of structurally and functionally variable IgA molecules in different animals should be taken into account when designing experimental strategies to induce mucosal antibody responses to human immunodeficiency virus (HIV).
Sulphasalazine inhibits macrophage activation: inhibitory effects on inducible nitric oxide synthase expression, interleukin‐12 production and major histocompatibility complex II expression
Authors: Haskó György , Szabó Csaba , Németh Zoltán H. , Deitch Edwin A. 
Published: March 2003

SummaryThe anti‐inflammatory agent sulphasalazine is an important component of several treatment regimens in the therapy of ulcerative colitis, Crohn's disease and rheumatoid arthritis. Sulphasalazine has many immunomodulatory actions, including modulation of the function of a variety of cell types, such as lymphocytes, natural killer cells, epithelial cells and mast cells. However, the effect of this agent on macrophage (Mφ) function has not been characterized in detail. In the present study, we investigated the effect of sulphasalazine and two related compounds – sulphapyridine and 5‐aminosalicylic acid – on Mφ activation induced by bacterial lipopolysaccharide (LPS) and interferon‐γ (IFN‐γ). In J774 Mφ stimulated with LPS (10 µg/ml) and IFN‐γ (100 U/ml), sulphasalazine (50–500 µm) suppressed nitric oxide (NO) production in a concentration‐dependent manner. The expression of the inducible NO synthase (iNOS) was suppressed by sulphasalazine at 500 µm. Sulphasalazine inhibited the LPS/IFN‐γ‐induced production of both interleukin‐12 (IL‐12) p40 and p70. The suppression of both NO and IL‐12 production by sulphasalazine was superior to that by either sulphapyridine or 5‐aminosalicylic acid. Although the combination of LPS and IFN‐γ induced a rapid expression of the active forms of p38 and p42/44 mitogen‐activated protein kinases and c‐Jun terminal kinase, sulphasalazine failed to interfere with the activation of any of these kinases. Finally, sulphasalazine suppressed the IFN‐γ‐induced expression of major histocompatibility complex class II. These results demonstrate that the Mφ is an important target of the immunosuppressive effect of sulphasalazine.
Regulation of T‐cell interaction with fibronectin by transforming growth factor‐β is associated with altered Pyk2 phosphorylation
Authors: Brill Alexander , Franitza Susanne , Lider Ofer , Hershkoviz Rami 
Published: March 2003

SummaryAlthough the involvement of transforming growth factor‐β (TGF‐β) in inflammatory reactions has been extensively studied, its mode of action in the context of the extracellular matrix (ECM) is still not fully understood. We undertook this study in an attempt to reveal the putative roles of TGF‐β in T‐cell adhesion and migration. We found that a 60‐min treatment of T cells with TGF‐β regulates T‐cell adhesion to fibronectin (FN), a prototype cell adhesion protein of the ECM, depending on the presence of other activators. At 5 pg/ml to 1 ng/ml, TGF‐β alone induced T‐cell adhesion to FN in an integrin α4/β1‐ and integrin α5/β1‐dependent manner. TGF‐β also attenuated T‐cell migration on the stromal cell‐derived factor (SDF)‐1α gradients. These effects of TGF‐β were not accompanied by alteration in the expression of very‐late activation antigen type 4 (VLA‐4) and VLA‐5, nor were they mediated by the cyclo‐oxygenase pathway. The cellular mechanism underlying the adhesion‐regulating activities of TGF‐β involves adhesion‐associated cytoskeletal elements. TGF‐β induced the phosphorylation of focal adhesion kinase Pyk2, but not extracellular signal‐regulated kinase (ERK), and this effect was markedly increased in the presence of immobilized FN, suggesting a collaborative role for FN‐specific integrins. Indeed, TGF‐β‐induced Pyk2 phosphorylation was inhibited by monoclonal antibodies against VLA‐4, VLA‐5 and CD29. Thus, TGF‐β, which may appear at extravascular sites during inflammation, affects the adhesion of T cells to ECM glycoproteins and their migration by its ability to differentially induce or inhibit the phosphorylation of Pyk2.
Size of the population of CD4+ natural killer T cells in the liver is maintained without supply by the thymus during adult life
Authors: Kameyama Hitoshi , Kawamura Toshihiko , Naito Tetsuya , Bannai Makoto , Shimamura Kazuhiko , Hatakeyama Katsuyoshi , Abo Toru 
Published: March 2003

SummaryGiven that there are few natural killer T (NKT) cells in the liver of athymic nude mice and in neonatally thymectomized mice, it is still controversial whether all NKT cells existing in the liver are supplied by the thymus or if some such cells develop in the liver. To determine whether or not NKT cells are consistently supplied from the thymus during adult life, thymectomy was conducted in mice at the age of 8 weeks. Interestingly, the proportion and number of CD4+ NKT cells increased or remained unchanged in the liver after adult thymectomy and this phenomenon continued for up to 6 months after thymectomy. The administration of α‐galactosylceramide induced severe cytopenia (due to apoptosis) of CD4+ NKT cells in the liver on day 1, but subsequent expansion of these NKT cells occurred in thymectomized mice similar to the case in normal mice. However, in thymectomized mice given lethal irradiation (9·5 Gy) and subsequent bone marrow transfer, the population of CD4+ NKT cells no longer expanded in the liver, although that of CD8+ NKT cells did. These results suggest that thymic CD4+ NKT cells, or their progenitors, may migrate to the liver at a neonatal stage but are not supplied from the thymus in the adult stage under usual conditions. CD8+ NKT cells can be generated in the liver.
Porcine dendritic cells generated in vitro: morphological, phenotypic and functional properties
Authors: Carrasco Carlos P. , Rigden Rachael C. , Schaffner Rene , Gerber Heidi , Neuhaus Viviane , Inumaru Shigeki , Takamatsu Haru , Bertoni Guiseppe , McCullough Kenneth C. , Summerfield Artur 
Published: March 2003

SummaryDespite the central role that dendritic cells (DC) play in immune regulation and antigen presentation, little is known about porcine DC. In this study, two sources of DC were employed. Bone marrow haematopoietic cell‐derived DC (BM‐DC) were generated using granulocyte–macrophage colony‐stimulating factor (GM‐CSF) in the presence or absence of tumour necrosis factor‐α (TNF‐α). Monocyte‐derived DC (Mο‐DC) were generated with GM‐CSF and interleukin‐4 (IL‐4). In both systems, non‐adherent cells developed with dendritic morphology, expressing high levels of major histocompatibility complex (MHC) class II. The presence of TNF‐α increased the BM‐DC yield, and enhanced T‐cell stimulatory capacity. Both BM‐DC and Mο‐DC expressed the pan‐myeloid marker SWC3, as well as CD1 and CD80/86, but were also CD14+ and CD16+. The CD16 molecule was functional, acting as a low‐affinity Fc receptor. In contrast, the CD14 on DC appeared to differ functionally from monocyte CD14: attempts to block CD14, in terms of lipopolysaccharide (LPS)‐induced procoagulant activity (PCA), failed. The use of TNF‐α or LPS for DC maturation induced up‐regulation of MHC class II and/or CD80/86, but also CD14. Allogeneic mixed leucocyte reactions and staphylococcal enterotoxin B antigen presentation assays demonstrated that these DC possessed potent T‐cell stimulatory capacity. No T helper cell polarization was noted. Both the BM‐DC and the Mο‐DC induced a strong interferon‐γ and IL‐4 response. Taken together, porcine DC generated in vitro possess certain characteristics relating them to DC from other species including humans, but the continued presence of CD14 and CD16 on mature and immature porcine DC was a notable difference.
Human leucocyte antigen‐A2 restricted and Mycobacterium tuberculosis 19‐kDa antigen‐specific CD8+ T‐cell responses are oligoclonal and exhibit a T‐cell cytotoxic type 2 response cytokine‐secretion pattern
Authors: Höhn Hanni , Kortsik Cornelius , Nilges Katja , Necker Antje , Freitag Kirsten , Tully Glenn , Neukirch Claudia , Maeurer Markus J. 
Published: March 2003

SummaryCD8+ T cells can be grouped into two different types of secretory T lymphocytes, based on the cytokine‐secretion pattern upon antigen exposure: those with a T‐cell cytotoxic type 1 response (Tc1), which secrete interferon‐γ (IFN‐γ), or those with a T‐cell cytotoxic type 2 response, which secrete interleukin (IL)‐4 and IL‐10. We examined the CD8+ T‐cell response directed against an immunodominant human leucocyte antigen (HLA)‐A2‐presented peptide derived from a 19‐kDa Mycobacterium tuberculosis‐associated antigen. T cells were examined by functional analysis and by T‐cell receptor (TCR) complementarity‐determining region 3 (CDR3)‐spectratyping, which defines the complexity of a T‐cell response. T‐cell stimulation with the immunodominant VLTDGNPPEV epitope yielded a Tc2 (IL‐4) cytokine‐secretion pattern and resulted in oligoclonal expansion of TCR‐variable beta chain (VB) families, which differed from patient to patient. Generation of T‐cell clones corroborated the notion that the CD8+ T‐cell response directed against the HLA‐A2‐presented VLTDGNPPEV epitope leads to a Tc2 cytokine‐secretion pattern in CD8+ T cells, as defined by IL‐4 and granulocyte–macrophage colony‐stimulating factor (GM‐CSF) release. Characterization of the cytokine‐secretion profile in HLA‐A2/VLTDGNPPEV‐tetramer sorted T cells from patients with active tuberculosis supported this observation: peptide‐specific T cells from three of three patients secreted IL‐4 and only one of three patients produced IFN‐γ in response to the nominal target epitope. Permutation of this T‐cell epitope may aid to elicit a qualitatively different CD8+ T‐cell response in patients with M. tuberculosis infection.
B‐cell precursors differentiated from cord blood CD34+ cells are more immature than those derived from granulocyte colony‐stimulating factor‐mobilized peripheral blood CD34+ cells
Authors: Hirose Yuka , Kiyoi Hitoshi , Itoh Katsuhiko , Kato Koji , Saito Hidehiko , Naoe Tomoki 
Published: March 2003

SummaryUmbilical cord blood (CB) has been widely used instead of bone marrow (BM) and peripheral blood (PB) for stem cell transplantation (SCT). However, problems of sustained immunodeficiency after CB transplantation remain to be resolved. To elucidate the mechanism of immunodeficiency, we compared the characteristics of B cells differentiated in vitro from CD34+ cells of CB with those of PB. Purified CD34+ cells from CB and PB were cultured on murine stroma cell‐line MS‐5 with stem cell factor and granulocyte colony‐stimulating factor for 6 weeks. The B‐cell precursors (pre‐B cells) that differentiated in this culture system, were analysed as to their immunoglobulin heavy chain (IgH) variable region gene repertoire and the expression of B‐cell differentiation‐related genes. CD10+ CD19+ pre‐B cells were differentiated from both PB and CB. Although the usages of IgH gene segments in pre‐B cells differentiated from CB and PB were similar, the N region was significantly shorter in CB‐derived than PB‐derived cells. Productive rearrangements were significantly fewer in cells of CB than PB in the third week. Among a number of B‐cell differentiation‐related genes, the terminal deoxynucleotidyl transferase (TdT) gene was not expressed in CB‐derived cells during the culture. These results indicated that immature features of pre‐B cells from CB, such as lack of TdT expression, and a short N region and few productive rearrangements in the IgH gene, might cause the delay in mature B‐cell production.
Neonatal mycobacterial specific cytotoxic T‐lymphocyte and cytokine profiles in response to distinct BCG vaccination strategies
Authors: Hussey Gregory D. , Watkins Marcia L. V. , Goddard Elizabeth A. , Gottschalk Sean , Hughes Elizabeth J. , Iloni Karen , Kibel Maurice A. , Ress Stanley R. 
Published: March 2003

SummaryThis study evaluated whether different bacillus Calmette–Gue´rin (BCG) strains, routes of administration, vaccination age and percutaneous tools influenced immune responses to BCG vaccination in infants. Proliferative responses, cytokine production and cell‐mediated cytotoxicity obtained in post‐vaccinated children were compared to baseline cord bloods and unvaccinated 10‐week‐old infants. BCG vaccination generally induced strong lymphoproliferative and T helper type 1 (Th1)‐type cytokine responses. There was a trend for greater responsiveness following the intradermal route of vaccination, with Japanese‐172 strain and with delaying vaccination until 10 weeks. Cord mononuclear cells differentially stimulated the Th2‐type cytokines interleukin‐5 (IL‐5) and IL‐10 selectively in response to BCG, as compared to H37Rv or purified protein derivative stimulation. We document for the first time the generation of mycobacterium‐specific cytotoxic T lymphocytes in neonates, following BCG vaccination. Cytotoxic activity correlated with the ratio of interferon‐γ to IL‐5, aside from a single instance where use of the Biovac® tool resulted in a striking dissociation selectively against H37Rv targets. These data have implications for correlates of protective immunity in design of vaccine studies.