bluuebunny/crossref_metadata_2025 huggingface dataset:
Antioestrogens Enhance Tumour Necrosis Factor Receptor 2 (TNF‐R2) Expression and TNF‐R2‐Mediated Proliferation in Activated T Cells
Authors: Komi  , Lassila
Published: March 2003

In the present study we demonstrate that the non‐steroidal antioestrogens toremifene and tamoxifen inhibit mitogen‐induced proliferation and up‐regulation of tumour necrosis factor (TNF) receptor family molecules on peripheral blood T cells. In activated T cells, however, toremifene and tamoxifen increase the surface expression of tumour necrosis factor receptor 2 (TNF‐R2). This up‐regulation is functionally important as TNF‐R2‐mediated proliferation is significantly enhanced in antioestrogen‐treated activated T cells. The regulation of TNF‐R2 expression in activated T cells seems to involve the c‐Jun amino terminal kinase (JNK) pathway, as activation of JNK with anisomycin down‐regulates TNF‐R2. In activated T cells toremifene clearly inhibits phorbol 12‐myristate 13‐acetate (PMA)‐induced JNK activity, suggesting that the JNK pathway may also be involved in the up‐regulation of TNF‐R2 expression by antioestrogens. Taken together, the enhancement of TNF‐R2 expression and TNF‐R2‐mediated proliferation in activated T cells represents a novel feature for the effects of antioestrogens. The inhibitory effects of toremifene on the JNK pathway demonstrates that antioestrogens can influence not only cell growth, but also a variety of other cellular responses by inhibiting protein kinase C (PKC).
Human T‐ and B‐Cell Reactivity to the 16 kDa α‐Crystallin Protein of Mycobacterium tuberculosis
Authors: Wilkinson  , Wilkinson  , De Smet  , Haslov  , Pasvol  , Singh  , Svarcova  , Ivanyi
Published: March 2003

The attributes of immunodominance, predominant expression during mycobacterial dormancy and restriction to the Mycobacterium tuberculosis complex make the 16 kDa protein an important candidate for the study of the immune response in humans. We therefore investigated the relationship between T‐ and B‐cell reactivity to the recombinant antigen and disease in a total of 127 subjects. The percentage of T‐cell responders towards both the intact antigen and its permissively recognised peptide 16p91‐110 was highest in healthy bacillus Calmette–Guérin (BCG)‐sensitized controls (96% and 68%, respectively) and lowest in those with extensive untreated tuberculosis (26% and 18%) (P < 0.001). By contrast, antibody levels (ABT50 > 100) were highest in patients with extensive disease (46–50%) (P < 0.005). There was significantly higher production of IFN‐γ in the BCG‐sensitized controls by comparison with untreated patients (P < 0.05), but complete antituberculous chemotherapy abolished this deficit in patients. The significance of these findings to immunodiagnosis and protective immunity is discussed.
Thalidomide Prolongs Experimental Autoimmune Neuritis in Lewis Rats
Authors: Zhu  , Deng  , Diab  , Zwingenberger  , Bakhiet  , Link
Published: March 2003

Thalidomide is reported to have immunomodulatory and anti‐inflammatory effects, which have led to its use in the treatment of a number of immune‐mediated disorders, including leprosy, discoid lupus and Behcet's disease, and to prevent immunological rejection phenomena following skin and bone marrow grafts. Experimental autoimmune neuritis (EAN) is a CD4+ T‐cell‐mediated demyelinating autoimmune disease, which represents an animal model for the study of the immunopathogenesis and immunotherapy of Guillain–Barré syndrome (GBS) in humans. We examined the effect of thalidomide in Lewis rats with EAN, which was induced by immunization with bovine peripheral nerve myelin (BPM) and complete Freund's adjuvant (CFA). Thalidomide prolonged clinical EAN when given at a dose of 200 mg/kg/day by gavage. This clinical effect was associated with increased numbers of inflammatory cells in sciatic nerve sections and elevated numbers of interferon‐γ (IFN‐γ) mRNA‐expressing cells among lymph node mononuclear cells from thalidomide‐treated EAN rats on day 17 postimmunization, i.e. at the peak of clinical EAN. The finding that thalidomide prolongs clinical EAN is in agreement with the clinical polyneuropathy reported in patients receiving treatment with thalidomide and limits its clinical usefulness.
Induction of Phagocyte‐Stimulating and Th1‐Promoting Cytokines by In Vitro Stimulation of Human Peripheral Blood Mononuclear Cells with Streptococcus pneumoniae
Authors: ARVÅ  , ANDERSSON
Published: March 2003

Polymorphonuclear granulocytes, which provide a major defence against Streptococcus pneumoniae infections, are attracted to and activated by various cytokines. The aim of this study was to analyse the cytokine response of human peripheral blood mononuclear cells to stimulation with S. pneumoniae. Strains belonging to serogroups 4, 6, 14, 19 or 23, were isolated from nasopharynx, middle ear fluid, cerebrospinal fluid or blood. All strains induced a marked proliferative response of the peripheral blood mononuclear cells; the stimulatory index was 34 ± 11. High levels of pro‐inflammatory cytokines were induced, i.e. interleukin (IL)‐1β (53 ± 25 ng/ml), IL‐6 (347 ± 41 ng/ml) and tumour necrosis factor (TNF)‐α (15 ± 4 ng/ml). Also, chemokines and immunoregulatory cytokines including IL‐8 (215 ± 224 ng/ml), IL‐10 (122 ± 60 pg/ml), IL‐12 (1195 ± 648 pg/ml), interferon (IFN)‐γ (18 ± 4 ng/ml) and granulocyte macrophage colony‐stimulating factor (135 ± 80 pg/ml) were induced. Several of these cytokines can up‐regulate phagocytosis and the killing of bacteria. Interestingly, strains isolated from middle ear fluid and blood elicited significantly fewer IL‐8 and significantly more IL‐12 and IL‐10 than strains from nasopharynx. They also induced a stronger proliferative response. Our results indicate that pneumococci are potent inducers of cytokines, especially IL‐12, favouring T‐helper cell type 1 (Th1) responses.
Natural Human Antibodies Retrieved by Phage Display Libraries from Healthy Donors: Polyreactivity and Recognition of Human Immunodeficiency Virus Type 1 gp120 Epitopes
Authors: Llorente  , Sánchez‐Palomino  , Mañes  , Lucas  , Kremer  , De Alborán  , Torán  , Alcamí  , Del Real  , Martínez‐A.
Published: March 2003

We have characterized the human natural antibody repertoire that contains antibodies recognizing the human immunodeficiency virus type 1 (HIV‐1) gp120. A panel of monovalent antigen‐binding fragments (Fab) selected from IgM and IgG isotype libraries generated from peripheral blood mononuclear cells (PBMC) of a healthy, HIV‐1 noninfected individual was analysed, reflecting that only IgM, but not IgG, Fab were able to recognize HIV‐1 gp120. The IgM Fab antibodies were not restricted to any particular heavy chain variable region (VH) germ line gene. However, the recognition of gp120 is associated to polyreactive antibodies and all display low‐affinity interaction. This correlates with the absence of any maturation process as somatic mutation or isotype switch as the nucleotide sequence analysis of the variable regions reveals they are expressed near to germline configuration. In addition, none of the antibodies showed any neutralizing activity on HIV‐1‐infected lymphocytes, reflecting that the natural anti‐gp120 repertoire is not sufficient to neutralize HIV infection.
Molecular Characterization of the VH1‐Specific Variable Region Determinants Recognized by Anti‐Idiotypic Monoclonal Antibodies G6 and G8
Authors: Potter  , Li  , Mageed  , Jefferis  , Capra
Published: March 2003

Mutational analysis was used to determine the structural basis for the binding of the murine anti‐idiotypic (anti‐Id) monoclonal antibodies (MoAb) G6 and G8 to VH1‐encoded antibodies. The MoAb G6 binds a cross‐reactive idiotope present on the heavy (H) chains of immunoglobulins (Ig) encoded by 51p1‐related gene segments, but not those encoded by hv1263‐related gene segments. Gene segments 51p1 (DP‐10) and hv1263 differ by only four amino acids; three in complementarity‐determining region 2 (CDR2), and one in framework region 3 (FR3). The MoAb G8 also binds 51p1‐related sequences, although it is undetermined whether G8 can bind hv1263‐related sequences. In order to localise the Ids recognized by MoAbs G6 and G8 on 51p1‐encoded antibodies, recombinant antibodies containing H‐chain mutants were expressed in insect cells. Idiotypic analysis on the expressed recombinant proteins definitively localised the reactivity in each molecule. These studies should be important in the structural appreciation for critical serological reagents.
Haematopathology of ‘Sjögren‐Mice’: Histopathological Changes in Spleens After Semiallogeneic Cell Transfer
Authors: USSING  , BAELDE  , OLESEN LARSEN  , NAESER  , PRAUSE  , BRUIJN
Published: March 2003

Haematopoietic transplantation chimeras may be readily produced in adult mice, using F1‐hybrids of selected inbred strains as recipients and mice from one of the parental strains as donors. We transplanted spleen cells from BALB/c donors into nonirradiateded F1‐hybrids of BALB/c and CBA/H‐T6. Both female and male recipients developed a primary Sjögren's syndrome‐like exocrinopathy without signs of kidney disease. At long‐term follow‐up, 7½ months after cell transfer, lymph nodes were enlarged, and spleens were diminished and irregular in shape. In general, changes in haematopoietic organs were more prominent in males. The results verify that although hybrid mice of either sex develop glandular manifestations comparable with primary Sjögren's syndrome, when the immune system is stimulated by semiallogeneic immunocytes, the evoked reactions in haematopoietic tissues show gender difference.
Antibodies Given Orally in the Neonatal Period Can Affect the Immune Response for Two Generations: Evidence for Active Maternal Influence on the Newborn's Immune System
Authors: Lundin  , Dahlman‐Höglund  , Pettersson  , Dahlgren  , Hanson  , Telemo
Published: March 2003

Two day old Wistar rats were tube fed with 1 or 10 μg of a mouse IgG1 monoclonal anti‐idiotypic (a‐Id) antibody that was directed against an anti‐Escherichia coli‐K13 capsular polysaccharide antibody. A control group was given 10 μg of an unrelated control antibody. Six weeks after the administration of antibodies, the rats were intestinally colonised with an ovalbumin (OVA)‐producing E. coli O6K13 strain. At 8 weeks of age, the male rats (first generation) and the offsprings of the female rats (second generation), were parenterally immunised with OVA and dead wild type E. coli O6K13, and the immune response was followed. In the rats of the first generation, there were no major differences between the groups in the immune response to the bacterium. However, the offspring of the neonatally a‐Id administered rats had a profoundly affected immune response to the idiotypically connected antigen K13, but also to other antigens on the bacteria. Thus, a‐Id treatment in the first generation gave, in the second generation, a greatly enhanced serum antibody response to the spatially related antigens OVA and O6 LPS, as well as to the idiotypically connected antigen K13. Concurrently, the in vitro spleen cell proliferative response to both OVA and the wild type bacterium was lowered. Overall, greater effects were seen with the higher dose of a‐Id. In conclusion, our results demonstrate that by giving monoclonal antibodies idiotypically connected to a single bacterial component to neonatal rats, one profoundly influence the immune response also to other—spatially related—bacterial antigens in their offsprings.
Prostaglandin E2 Inhibits Lesion Formation in Dextran Sodium Sulphate‐Induced Colitis in Rats and Reduces the Levels of Mucosal Inflammatory Cytokines
Authors: Sasaki  , Hirata  , Maemura  , Hamamoto  , Murano  , Toshina  , Katsu
Published: March 2003

Effects of rectally injected prostaglandin E2 (PGE2) in rats with dextran sodium sulphate (DSS)‐induced colitis were investigated in terms of histopathology, local myeloperoxidase (MPO) activity, local mRNA expression of interleukin‐1β (IL‐1β), tumour necrosis factor‐α (TNF‐α) and growth‐regulated gene produced/cytokine‐induced neutrophil chemoattractant (GRO/CINC)‐1, and secretion of TNF‐α and GRO/CINC‐1. In animals with no PGE2 treatment, DSS‐induced erosion and ulceration were particularly severe in the rectum and extended to the proximal colon. Neutrophil infiltration was characteristically present in the lesions and surrounding mucosa. MPO activity at lesion sites was increased. IL‐1β and GRO/CINC‐1 mRNA expression was increased, while TNF‐α mRNA expression was significantly decreased. GRO/CINC‐1 secretion was increased but a similar elevation of TNF‐α was not detected. In the PGE2‐treated group, lesion formation was inhibited grossly and microscopically. Neutrophil infiltration and MPO activity in and around lesions were lessened. The reduction in TNF‐α mRNA expression and secretion was not affected by PGE2. The expression of mRNA for IL‐1β and GRO/CINC‐1 was reduced, as was the secretion of GRO/CINC‐1. As mRNA expression and secretion of cytokines in lesions of non‐PGE2‐treated animals was similar to that reported in human ulcerative colitis, rectal injection of PGE2 may prove to be an effective therapy.
Flt‐3 Ligand, in Combination with Bovine Granulocyte–Macrophage Colony‐Stimulating Factor and Interleukin‐4, Promotes the Growth of Bovine Bone Marrow Derived Dendritic Cells
Authors: Hope  , Werling  , Collins  , Mertens  , Howard
Published: March 2003

Culture of bone marrow precursor cells with cytokines, including granulocyte–macrophage colony‐stimulating factor (GM–CSF), interleukin‐4 (IL‐4) and the tyrosine kinase receptor binding proteins Flt‐3 ligand (Flt‐3L) and stem‐cell factor (SCF), has previously been shown, in both mouse and human, to result in the generation of large numbers of dendritic cells. We extend these findings to bovine dendritic cells. Culture of bovine bone marrow cells with GM–CSF, IL‐4 and either Flt‐3L or SCF enhanced the generation of low buoyant‐density dendritic cells. However, only the addition of Flt‐3L to cells cultured with GM–CSF and IL‐4 was shown to increase the number of dendritic cells and induce the differentiation of dendritic cells with potent capacity to stimulate allogeneic T cells and resting CD4+ memory T cells. The effective ability to stimulate T cells was associated with the expression of major histocompatibility complex (MHC) class II molecules and CD80/86 by dendritic cells. Bovine bone marrow derived dendritic cells appeared to be exclusively of myeloid origin because they expressed the myeloid‐related antigens CD14, MyD‐1 and CD11b.
Independent Genetic Control of B‐ and T‐Cell Tolerance in Strains of Mouse Selected for Extreme Phenotypes of Oral Tolerance
Authors: Da Silva M. F. S. , Da Costa S. C. G. , Ribeiro R. C. , Sant'anna O. A. , Da Silva A. C.
Published: March 2003

Two strains of mice were genetically selected for susceptibility (TS‐Ab/HetS strain) or resistance (TR‐Ab/HetS strain) to oral tolerance of the humoral response by using ovalbumin (OVA). The progressive interstrain divergence produced by bi‐directional selective breeding during 15 generations demonstrated the polygenic nature of oral tolerance. This paper shows the humoral and delayed‐type hypersensitivity (DTH) responses, after intragastric administration of OVA and subsequent immunization with that immunogen in complete Freund adjuvant (CFA). Only the TS‐Ab/HetS mice were tolerant for immunoglobulin (Ig)G production with its tolerance degree being the same as that obtained when Al (OH)3 was employed. The DTH reactivity was not correlated to the antibody responsiveness, because both the TS‐Ab/HetS and TR‐Ab/HetS strains had their DTH reactions suppressed. The cyclophosphamide (Cy) pretreatment prevented DTH suppression on TR‐Ab/HetS but do not in TS‐Ab/HetS mice. Interstrain difference was also observed for the splenic index in the Cy‐treated groups, although the number of splenocytes was the same. Flux cytometry cell analysis showed the recovery of CD3+ cell numbers in both strains, but only the TR‐Ab/HetS mice had their CD4/CD8 pattern restored. These results suggest: firstly, the independent control of DTH and humoral tolerance responsiveness; secondly no support for the clonal anergy concept; and thirdly the matrix proteins neo‐synthesis after Cy treatment may facilitate the tolerance abrogation.
Serum Amyloid P‐Component‐Induced Colony‐Stimulating Factors Production by Macrophages
Authors: Singh S. , Singh P. P.
Published: March 2003

Purified mouse serum amyloid P‐component (SAP; 0.5‐50 µg/kg), injected intravenously into Swiss mice, induced the production of serum colony‐stimulating factors (CSFs); the maximum induction was observed at 10.0 µg/kg. Further, in vitro purified mouse SAP (0.1‐50 µg/ml) stimulated the mouse elicited peritoneal macrophages to elaborate CSFs in the conditioned medium (CM); 5.0 µg/ml SAP appeared to be the optimum. Both in vivo and in vitro the maximum production of CSFs occurred 6 h after initiation of stimulation, and returned to the background levels by 48 h. Mannose 6‐P, mannose 1‐P and mannose, and not other sugars inhibited the SAP‐induced production of CSFs by macrophages which suggests that SAP interaction with macrophages was mediated by specific glycoprotein‐receptors. A neutralizing (100%) concentration of rabbit antimouse interleukin (IL)‐1 polyclonal antibody had no effect on the SAP‐induced CSF production, indicating that it would be IL‐1‐independent. SAP‐induced CSFs, both in serum and CM, were functionally similar as they supported the formation of granulocyte (G), macrophage (M) and GM colonies in similar proportions. The production of CSFs appeared to be lipopolysaccharide (LPS)‐independent as it was not inhibited by polymyxin B sulfate (25.0 µg/ml), and heat‐inactivated (80 °C, 1 h, pH 7.0) SAP did not induce the production of CSFs. The CSFs were produced de novo because cylcoheximide (50.0 µg/ml) completely inhibited their production. These results demonstrate that purified mouse SAP, in a dose‐dependent manner, can induce the production of serum CSFs in mice, and can induce LPS‐independent de novo production of CSFs by elicited macrophages in vitro.
Possible Involvement of IL‐12 in Reovirus Type‐2‐Induced Diabetes in Newborn DBA/1 Mice
Authors: Hayashi T. , Morimoto M. , Iwata H. , Onodera T.
Published: March 2003

This study extends our previous observations that the reovirus type‐2(Reo‐2) can induce autoimmune insulitis, which may be mediated by T‐helper(Th)1‐dependent mechanisms, resulting in diabetes in newborn DBA/1 mice. In this study mRNA expression for Th1‐related cytokines including Th1 and Th2 cytokines in splenic cells was examined by reverse transcriptase polymerase chain reaction (RT–PCR) in relation to the development of insulitis. Furthermore, the effect of monoclonal antibody (MoAb) against interleukin (IL)‐12(p40) on the development of insulitis and the mRNA expression in the splenic cells was examined. The mRNA expression for IL‐12(p40), IL‐18, and interferon (IFN)‐γ, but not IL‐5, increased in the spleen in parallel with the development of insulitis. The treatment with MoAb to IL‐12(p40) reduced the insulitis with diabetes which was associated with a decrease in the mRNA expression for IL‐12(p40), IL‐18 and IFN‐γ, and an increase of IL‐4 mRNA expression in the spleen. The present study suggested that Th1‐dominant systemic immune responses, being responsible for the development of autoimmune insulitis, might be induced by IL‐12‐induced and IL‐18‐activated mechanisms.
Recent Progress in the Understanding of B‐Cell Functions in Autoimmunity
Authors: Porakishvili N. , Mageed R. , Jamin C. , Pers J.‐O. , Kulikova N. , Renaudineau Y. , Lydyard P. M. , Youinou P.
Published: March 2003

Our early concepts of the normal role of B cells in immunity focused on their ability to produce antibodies (Ab) and in the case of autoimmune diseases autoAbs, some of which were pathogenic. Over the past 10 years, it has became apparent that B cells display a variety of characteristics, other than Ab production, which could contribute to autoimmunity. They normally play a role in the development of lymphoid architecture, regulating T‐cell subsets and dendritic cell (DC) function through cytokine production, and in activation of T cells. Receptors editing is also important in B cells which aids in immunity to infection and, possibly, prevention of autoimmunity. Transgenic animal models have now shown that B cells are necessary for many autoimmune diseases although their Ab products are not required in some cases. Negative signalling by CD5 and other molecules, such as CD22, in maintaining tolerance through recruitment of src‐homology two domain‐containing protein tyrosine phosphatase‐1 has also been documented. In fact, we have now reached a new era whereby the B cell has returned as an important contributor to autoimmune disorders, so that the race is on to characterize signalling regulation via the B‐cell receptor and coreceptors. Identification of such molecules and their potential defects should lead to effective ways of controlling the immune response and in particular preventing the development of autoimmune states. The classical view of B cells in the biology of immune responses to infectious and self‐antigens (Ag) that they promote immunity primarily by producing Ab turns out to be rather naïve. Indeed, studies over the last few years indicate that this view is far from complete, and suggest that B lymphocytes have extraordinarily diverse functions within the immune system. Furthermore, it is becoming increasingly clear that the pathogenesis of autoimmune diseases cannot solely be accounted for by T cells, and intrinsic abnormalities of B cells have been described in such conditions. In this brief review we highlight some recent observations in the context of B lymphocyte in pathophysiology, and focus on their revival as pivotal players the pathophysiology in autoimmune diseases. Yet, it remains difficult to provide a model of how important B cells are in immunity and autoimmunity.
The Effect of In vivo Depletion of NKR‐P1+ or CD8+ Lymphocytes on the Acute Rejection of Allogeneic Lymphocytes (ALC) in the Rat
Authors: Løvik G. , Vaage J. T. , Rolstad B. , Naper C.
Published: March 2003

We have depleted lymphocyte subsets in PVG and AO rats with MoAbs 3.2.3 (against NKR‐P1 on NK and NK/T cells) and OX‐8 (against CD8 on CTL and NK cells), and examined the effect on the killing of YAC‐1 target cells in vitro and the effect on the acute rejection of small allogeneic lymphocytes in vivo (allogeneic lymphocyte cytotoxicity, ALC). While 3.2.3 treatment led to only a partial depletion of 3.2.3‐positive cells in PVG rats, this treatment drastically reduced the number of NKR‐P1+ cells in AO rats, abolished splenic NK activity against the NK‐sensitive tumour target YAC‐1, and markedly diminished the ALC response. Rats treated with OX‐8 for 1 day showed a similar loss of NK cell function in vivo and in vitro. However, in rats treated with OX‐8 for 3 days a 3.2.3+ and OX‐8− population consisting of NK cells appeared, restoring ALC. The results demonstrate that NK cell responses can be greatly diminished after in vivo treatment with these MoAbs. Furthermore, they demonstrate that ALC is not necessarily linked to expression of the CD8 molecule.
The Role of Surface Ig Binding in the Activation of Human B Cells by Phosphorothioate Oligodeoxynucleotides
Authors: Liang H. , Reich C. F. , Pisetsky D. S. , Lipsky P. E.
Published: March 2003

Phosphorothioate oligodeoxynucleotides (sODNs) can induce T‐cell‐independent polyclonal activation of human B cells by a mechanism that depends on both sequence and back‐bone structure. Because matrix‐bound as well as soluble sODNs are mitogenic, this stimulation may result from the engagement of surface receptor(s). In order to investigate whether surface immunoglobin (Ig) could be a receptor for sODNs, the interaction of sODNs–fluorescein isothiocyanate (FITC) with Ig‐coated beads was examined. sODNs specifically bound to human IgM and IgG. Moreover, binding of sODN to human B cells induced temperature‐dependent capping of bound receptors and colocalization of FITC–sODN and IgM into aggregated caps on the surface of human B cells. A role of surface Ig was furthermore shown by observations that antibody‐mediated capping of B‐cell surface IgM or IgD inhibited subsequent binding of sODNs and that the capacity of sODN to stimulate human B cells was blocked by excess IgM or IgG, by nonstimulatory antibodies to sIgM, as well as by a variety of negatively charged molecules. Together, these results indicate that sODNs engage surface Ig by charge–charge interactions that lead to activation of human B cells.
A pTα‐Negative Subpopulation of CD25+ TN Thymocytes Revealed by a Transgenic Marker
Authors: Petersson K. , Mårtensson A. , Mertsching E. , Winkler T. , Ceredig R. , Mårtensson I.‐L. , Ivars F.
Published: March 2003

We have recently generated 5′λ5‐huTAC mice, which express the human CD25 (huTAC) gene under the control of the 5′‐flanking region of the mouse λ5‐gene. The huTAC‐transgene was expressed in pre‐B cells but neither in mature B cells nor in T cells of these mice. In this report we demonstrate that the transgene is also transiently expressed by adult CD25+ CD3−CD4−CD8− (triple negative, TN) thymocytes and in fetal thymocytes. The huTAC+, in contrast to the huTAC− subpopulation of the CD44+CD25+ TN cells, was unexpectedly found not to express the pTα‐gene. Still the huTAC+CD44+CD25+ TN cells reconstituted the development of both αβ and γδ lineage cells equally efficiently as the pTα‐expressing huTAC− fraction, demonstrating that this pTα‐negative subpopulation contained precursors for both T‐cell lineages. Single cell reverse transcription–polymerase chain reaction (RT–PCR) experiments demonstrated that also in normal mice only a fraction of CD44+CD25+ and CD44−CD25+ TN cells expressed this gene. Taken together, these data indicate that huTAC transgene expression revealed a truly pTα‐negative fraction of the CD44+CD25+ TN cells. The observation that not all precursors in the CD25+ TN population express the pTα‐gene has important implications for the understanding of early T‐cell development and T‐cell lineage commitment.
Haptoglobin Interacts with the Human Mast Cell Line HMC‐1 and Inhibits its Spontaneous Proliferation
Authors: El‐Ghmati S. M. , Arredouani M. , Van Hoeyveld E. M. , Ceuppens J. L. , Stevens E. A. M.
Published: March 2003

Haptoglobin (Hp) is an acute phase reactant produced by hepatocytes. There is evidence for an immunomodulatory potential of Hp, though there is no clear evidence yet about the mechanisms of this action. We have previously shown that Hp interacts with the β2‐integrin CD11b/CD18. In addition, other investigators reported the binding of Hp to B lymphocytes through the CD22 receptor, and to neutrophils through two different receptors.

In the present study, we investigated the interaction of haptoglobin with the human mast cell line HMC‐1. We report that fluorescein isothiocyanate (FITC)‐labelled haptoglobin binds to this cell line and that binding is increased by calcium in a dose‐ and time‐dependent manner. Hp binding sites on HMC‐1 were upregulated upon stimulation with phorbol myristate acetate (PMA)/A23187 and after treatment with anti‐CD43 and anti‐CD44 monoclonal antibodies (MoAbs). HMC‐1 cells do not express either CD11b/CD18 or CD22 receptors, indicating that the haptoglobin‐binding receptor on this cell line is different from the known receptors. Assessment of cell function showed that Hp inhibits the spontaneous growth of HMC‐1 up till 40% at higher Hp concentrations, but it did not exhibit any effect on the expression of CD54 on the release of either tryptase or IL‐1ra.

In conclusion, haptoglobin binds specifically to human mast cells via a receptor different from CD11b/CD18 and CD22, and may play a role in the modulation of mast cell functions. Exploration of Hp effects in mast cell‐dependent diseases such as allergic rhinitis and urticaria seems warranted.
Effects of Anti‐Neutrophil Cytoplasm Autoantibodies on Tissue Factor Activity by HL‐60 Cells In Vitro
Authors: Flores‐Suárez L. F. , Nowack R. , Yard B. A. , Dempfle C.‐E. , Van Der Woude F. J.
Published: March 2003

The effects of cytoplasmic anti‐neutrophil cytoplasm autoantibodies (C‐ANCA) and perinuclear ANCA (P‐ANCA) immunoglobulin G (IgG) on tissue factor (TF) activity using HL‐60 cells in vitro were compared with those of medium, lipopolysaccharide (LPS) and control IgG. Cells were also incubated with both ANCA IgG and control IgG in the presence of a submaximal concentration of LPS capable of upregulating TF procoagulant activity (TF‐PCA) measured in arbitrary units of TF equivalent (AU‐TFEq). The purpose was to search for an additive effect between LPS and ANCA IgG. All IgG preparations increased HL‐60 cell TF‐PCA in comparison with the medium. When cells were incubated with P‐ANCA IgG and LPS (1 µg/ml), a larger increase was seen (151.23 ± 31.6 SEM (standard error of the mean) AU‐TFEq) than when incubated with control IgG plus LPS (91.01 ± 18.4 SEM AU‐TFEq; P < 0.005), P‐ANCA IgG alone (73.68 ± 12.7 SEM AU‐TFEq; P < 0.005) or LPS (1 µg/ml) (58.11 ± 7.9 SEM AU‐TFEq; P < 0.005). There was concordance between PCA and TF total antigen content by enzyme‐linked immunosorbent assay (ELISA). The fact that P‐ANCA IgGs upregulate the function of TF in HL‐60 cells in combination with LPS adds to information regarding the possible role of ANCAs in the enhancement of TF by different cells, although it does not support the fact that ANCAs alone play a role in mononuclear cell TF upregulation. The additive effects of LPS underline the possible role of pro‐inflammatory stimuli in the pathogenesis of ANCA‐associated diseases.
Cytokine Production and Expression of Leucocyte‐Differentiation Antigens by Human Mononuclear Cells in Response to Mycobacterium tuberculosis Antigens
Authors: Cubillas‐Tejeda A. C. , Ruiz‐Argüelles A. , Bernal‐Fernández G. , Quiroz‐Compeán L. , López‐Dávila A. , Reynaga‐Hernández E. , González‐Amaro R.
Published: March 2003

The aim of this work was to characterize a leucocyte‐differentiation antigen or chemokine receptor that allows the identification of type 1 (T helper 1 (Th1), Tc1) and type 2 (Th2, Tc2) lymphocytes in short‐term‐cultured human peripheral blood mononuclear cells. In addition, we assessed the type of response induced by mycobacterial antigens in tuberculosis patients and healthy contacts. Cells were stimulated with an unfractionated culture filtrate or 30 kDa antigen from Mycobacterium tuberculosis. Then, CD4 and CD8 cell labelling was combined with CD30, CD27, CD28, CD45RA or CD45R0 staining, detection of intracellular interferon‐γ (IFN‐γ) or interleukin‐4 (IL‐4) and analysis by three‐colour flow cytometry. In separate experiments, the expression of different chemokine receptors (CCR1, CCR3, CCR5, CXCR3 and CXCR4) was also studied. We found that none of the cell‐surface molecules studied was preferentially expressed by Th1 or Th2 cells. Thus, our results indicate that these lymphocyte subsets cannot be identified in short‐term‐cultured mononuclear cells on the basis of preferential expression of the cell markers studied, and that it is necessary to look for additional molecules that allow the discrimination of Th1 and Th2 cells.
Human Th1 Cell Lines Recognize the Mycobacterium tuberculosis ESAT‐6 Antigen and its Peptides in Association with Frequently Expressed HLA Class II Molecules
Authors: Mustafa A. S. , Shaban F. A. , Al‐Attiyah R. , Abal A. T. , El‐Shamy A. M. , Andersen P. , Oftung F.
Published: March 2003

We have used a synthetic‐peptide approach to map epitope regions of the Mycobacterium tuberculosis ESAT‐6 antigen recognized by human T cells in relation to major histocompatibility complex (MHC) restriction. ESAT‐6‐specific CD4+ T‐cell lines were established by stimulating peripheral blood mononuclear cells from 25 HLA‐DR‐typed tuberculosis patients with complete antigen in vitro. The established T‐cell lines were then screened for proliferation and interferon‐γ (IFN‐γ) secretion in response to eight overlapping 20‐mer peptides covering the ESAT‐6 sequence. The response of the T‐cell lines to ESAT‐6 and peptides from a human leucocyte antigen (HLA)‐heterogeneous group of donors suggested the presence of multiple epitopes and promiscuous recognition of the antigen. Analysis of antigen and peptide recognition in the presence of anti‐HLA class I and class II antibodies suggested that the T‐cell lines recognized ESAT‐6 in association with HLA‐DR and ‐DQ molecules. Furthermore, testing of selected T‐cell lines with ESAT‐6 and the peptides in the presence of autologous and allogeneic HLA‐DR‐ and ‐DQ‐typed antigen‐presenting cells identified HLA‐DR2, ‐DR52 and ‐DQ2 amongst the HLA molecules involved in the presentation of ESAT‐6 and its peptides to human Th1 cells. In addition, the T‐cell lines were cytotoxic for monocytes and macrophages pulsed with ESAT‐6 and peptides. In conclusion, the recognition of ESAT‐6 by IFN‐γ‐secreting and cytotoxic CD4+ T cells in association with frequently expressed HLA class II molecules supports the application of this antigen to either specific diagnosis or subunit vaccine design.
Antineutrophil Cytoplasmic Antibodies Induce Decreased CD62L Expression and Enhanced Metabolic Activity in Monocytes
Authors: Wikman A. , Fagergren A. , Forslid J. , Jacobson S. H. , Johansson S. G. O. , Lundahl J.
Published: March 2003

Monocyte in vitro activation by antimyeloperoxidase (anti‐MPO)‐ and antiproteinase‐3 (anti‐PR3)‐positive sera, corresponding immunoglobulin G (IgG) fractions and monoclonal antibodies against MPO and PR3 was evaluated. The expression of adhesion molecules, l‐selectin (CD62L) and CR3 (CD11b), involved in leucocyte endothelial adhesion, and metabolic activity, measured as the production of hydrogen peroxide, were analysed. Decreased expression of CD62L was demonstrated in monocytes after incubation with antineutrophil cytoplasmic antibody (ANCA)‐positive sera. This finding was not accompanied by changes in CD11b expression. Metabolic activity was increased in monocytes after incubation with ANCA‐positive IgG fractions as well as after incubation with monoclonal anti‐MPO and anti‐PR3. These findings support the concept that the pathophysiological effect of ANCA is partly mediated through the action on crucial events in monocyte activation, such as CD62L downregulation and oxygen radical production.
Fluid–rock reactions in an evaporitic mélange, Permian Haselgebirge, Austrian Alps
Authors: SPÖTL C. , LONGSTAFFE F. J. , RAMSEYER K. , KUNK M. J. , WIESHEU R.
Published: March 2003

Tectonically isolated blocks of carbonate rocks present within the anhydritic Haselgebirge mélange of the Northern Calcareous Alps record a complex history of deformation and associated deep‐burial diagenetic to very low‐grade metamorphic reactions. Fluids were hot (up to ≈ 250 °C) and reducing brines charged with carbon dioxide. Individual carbonate outcrops within the mélange record different regimes of brine–rock reactions, ranging from pervasive dolomite recrystallization to dedolomitization. Early diagenetic features in these carbonates were almost entirely obliterated. Matrix dolomite alteration was related to thermochemical sulphate reduction (TSR) recognized by the replacement of anhydrite by calcite + pyrite ± native sulphur. Pyrite associated with TSR is coarsely crystalline and characterized by a small sulphur isotope fractionation relative to the precursor Permian anhydrite. Carbonates associated with TSR show low Fe/Mn ratios reflecting rapid reaction of ferrous iron during sulphide precipitation. As a result, TSR‐related dolomite and calcite typically show bright Mn(II)‐activated cathodoluminescence in contrast to the dull cathodoluminescence of many (ferroan) carbonate cements in other deep‐burial settings. In addition to carbonates and sulphides, silicates formed closely related to TSR, including quartz, K‐feldspar, albite and K‐mica. 40Ar/39Ar analysis of authigenic K‐feldspar yielded mostly disturbed step‐heating spectra which suggest variable cooling through the argon retention interval for microcline during the Late Jurassic. This timing coincides with the recently recognized subduction and closure of the Meliata‐Hallstatt ocean to the south of the Northern Calcareous Alps and strongly suggests that the observed deep‐burial fluid–rock reactions were related to Jurassic deformation and mélange formation of these Permian evaporites.
Experiments on bidisperse, constant‐volume gravity currents: propagation and sediment deposition
Authors: GLADSTONE  , PHILLIPS  , SPARKS
Published: March 2003

Laboratory experiments show that the propagation and sedimentation patterns of particle‐laden gravity currents are strongly influenced by the size of suspended particles. The main series of experiments consisted of fixed‐volume releases of dilute mixtures containing two sizes of silicon carbide particles (25 μm and 69 μm mean diameter) within a 6‐m flume. Polydisperse experiments involved mixtures of five different particle sizes and variation of the amounts of the finest and coarsest particles. All variables apart from the initial relative proportions of particles were identical in the experiments. The effects of mixing different proportions of fine and coarse particles is markedly non‐linear. Adding small amounts of fine sediment to a coarse‐grained gravity current has a much larger influence on flow velocity, run‐out distance and sedimentation patterns than adding a small amount of coarse sediment to a fine‐grained gravity current. The experiments show that adding small amounts of fine particles to a coarse‐grained current results in enhanced flow velocities because the fine sediment remains suspended and maintains an excess current density for a much longer time. Thus, the distance to which coarse particles are transported increases substantially as the proportion of fines in the flow is increased. Our experiments suggest that sandy turbidity currents containing suspended fines will be much more extensive than turbidity currents composed of clean sand.
Fracturing and fluid migration during Palaeogene compression and Neogene extension in the Catalan Coastal Ranges, Spain
Authors: TRAVÉ A. , CALVET F. , SOLER A. , LABAUME P.
Published: March 2003

The Catalan Coastal Ranges (NE part of the Eastern Iberian Margin) correspond to a system of grabens formed at the north‐western margin of the Valencia Trough. Extensional activity in the Catalan Coastal Ranges occurred at least from early to late Miocene and reactivated earlier transpressive faults related to the Palaeogene compression. In the central part of the Catalan Coastal Ranges, tectonic micro and macrostructures (faults, joints, stylolites) are well developed in the Mesozoic (mainly Cretaceous) limestones as well as in the Miocene graben fill deposits. In these rocks, seven generations of fractures, which formed during different tectonic phases, have been distinguished. Type 1–4 fractures affect only the Cretaceous limestones, type 5 and 6 fractures the Cretaceous and Miocene deposits, and type 7 fractures only the Miocene sediments. The fractures are filled with calcites, and locally with an internal sediment or a dolomite cement. The Cretaceous host‐rock has an average δ18O value of –4·3‰ PDB (Peedee Belemnite), an average δ13C value of +0·6‰ PDB, a 87Sr/86Sr ratio of 0·70741, up to 5630 p.p.m. of Mg2+, up to 2615 p.p.m. of Sr2+, and up to 1560 p.p.m. of Fe2+. Type 2 fractures are related to Palaeogene compression. The calcite cement filling this type of fracture has an average δ18O value of –8·2‰ PDB, an average δ13C value of –0·6‰ PDB, a 87Sr/86Sr ratio of 0·70714, up to 4560 p.p.m. of Mg2+, up to 3275 p.p.m. of Sr2+, and up to 3540 p.p.m. of Fe2+. These results indicate a fluid characterized by a high rock–fluid interaction approaching a closed system equilibrium.

Type 5 fractures are related to the syn‐rift stage. The calcite cement filling this type of fracture has an average δ18O value of –6·9‰ PDB, an average δ13C value of –4·3‰ PDB, a 87Sr/86Sr ratio of 0·70787, up to 5375 p.p.m. of Mg2+, up to 1750 p.p.m. of Sr2+ and up to 2855 p.p.m. of Fe2+. These results indicate a fluid characterized by a low rock–fluid interaction and an open hydrogeological system. The cements filling the compressional fractures are characterized by undulose extinction, subgrain formation and deformed mechanical twin planes indicating formation under stressed conditions. In contrast, cements filling extensional fractures are characterized by translucent crystals with uniform extinction, indicating free growth not subjected to stress.
Images of concentrations of dissolved sulphide in the sediment of a lake and implications for internal sulphur cycling
Authors: Lehmann Christine , Bachofen Reinhard
Published: March 2003

The high‐resolution mapping of dissolved sulphide in modern sediment of a permanently stratified (meromictic) lake is possible using a novel sulphide imaging technique (called a ‘sulphur print’). The technique is simple, easy to use and can map a relatively large area (up to several dm2). In situ sulphur prints from anoxic fine‐grained sediments are able to reveal internal structures in apparently homogeneous materials. Sulphur prints have been used to examine the formation and distribution of dissolved sulphide in the sediment and water column of the meromictic Lake Cadagno (southern Switzerland). The prints show clearly that a previously unknown laminar convective flow of sulphide‐free porewater occurs across the sediment–water interface. Such convective flow out of the sediment must be accompanied by convective flow of sulphide‐ and sulphate‐rich lake water into the sediment, and may be an important mechanism for the accumulation of sulphur in the sediment.
Postglacial growth history of a French Polynesian barrier reef tract, Tahiti, central Pacific
Authors: Cabioch  , Camoin  , Montaggioni
Published: March 2003

The internal structure and growth pattern of Tahiti reefs over the last 14 ka is reconstructed using sedimentological, morphological and palaeobiological data coupled with radiometric dates in drill cores through the modern barrier reef. Flooding of the volcaniclastic deposits or the karst surface of a Pleistocene reef started at ≈ 14 ka BP, and coral growth began shortly after inundation. The sequence in the Tahiti barrier‐reef edge has formed predominantly through long‐term keep‐up growth controlled by stable environmental conditions, while the adjacent backreef deposits did not start to accumulate before sea‐level stabilization, around 6 ka. The dominance of Porites communities and the coeval occurrence of branching gracile Lithophyllum in the lowermost part of the postglacial reef sequence (14–11 ka) suggest the prevalence of uniformly moderate‐ to low‐energy conditions and/or growth in slightly deeper waters all over the drilled area during the early reef stages. During the last 11 ka, the reef frameworks developed in a high‐energy environment, at maximum water depths of 5–6 m, and were dominated by an Acropora robusta/danai–Hydrolithon onkodes association; the local interlayering of other coralgal assemblages (dominated by tabular Acropora or domal Porites) reflects distinct diversification stages, resulting either from the palaeotopographic control of the substrate or from slight and episodic environmental changes.
Sedimentary processes and facies of the waterlaid Anvil Spring Canyon alluvial fan, Death Valley, California
Authors: Blair Terence C.
Published: March 2003

The Anvil Spring Canyon fan of the Panamint Range piedmont in central Death Valley was built entirely by water‐flow processes, as revealed by an analysis of widespread 2‐ to 12‐m‐high stratigraphic cuts spanning the 9·7 km radial length of this 2·5–5·0° sloping fan. Two facies deposited from fan sheetfloods dominate the fan from apex to toe. The main one (60–95% of cuts) consists of sandy, granular, fine to medium pebble gravel that regularly and sharply alternates with cobbly coarse to very coarse pebble gravel in planar couplets 5–25 cm thick oriented parallel to the fan surface. The other facies (0–25% of cuts) comprises 10‐ to 60‐cm‐thick, wedge‐planar and wedge‐trough beds of pebbly sand and sandy pebble gravel in backsets sloping 3–28°. Both facies are interpreted as resulting from rare, sediment‐charged flash floods from the catchment, and were deposited by supercritical standing waves of expanding sheetfloods on the fan. Standing waves were repeatedly initiated, enlarged, migrated, and then terminated either by gradually rejoining the flood or by more violent breakage and washout. The frequent autocyclic growth and destruction of standing waves during an individual sheetflood resulted in the deposition of multiple coarse and fine couplet and backset sequences 50–250 cm thick across the active depositional lobe of the fan. Erosional intensity during washout of the standing wave determined whether early‐phase backset‐bed deposits or washout‐phase sheetflood couplet deposits were selectively preserved in a given cycle. Two minor facies are also found in the Anvil fan. Pebble–cobble gravel lags (0–20% of cuts) are present above erosional scours into the sheetflood couplet and backset deposits. They consist of coarse gravel concentrated through fine‐fraction winnowing of the host sheetflood facies by sediment‐deficient water flows. This reworking occurred during recessional flood stage or from non‐catastrophic discharge during the long intervals between major flash floods. This facies is common at the surface, giving rise to a ‘braided‐stream’ appearance. However, it is stratigraphically limited, present as thin, continuous to discontinuous beds or lenses that bound 50‐ to 250‐cm‐thick sheetflood sequences. The other minor facies of the Anvil fan consists of clast‐supported and imbricated, thickly stratified, pebbly, cobbly, boulder gravel present in narrow, radially aligned ribbons nested within sheetflood deposits. This facies is interpreted as representing deposition in the incised channel of the fan, a subenvironment characterized by greater flow competence resulting from maintained depth from channel‐wall confinement, and by more frequent water flows and winnowing events caused by its direct connection with the catchment feeder channel.
Compaction in halite‐cemented carbonates – the Dawson Bay Formation (Middle Devonian) of Saskatchewan, Canada
Authors: Kendall Alan C.
Published: March 2003

Halite‐impregnated carbonates in the Dawson Bay Formation of Saskatchewan lie between beds of halite and are buried to a depth of 1 km. They exhibit two different diagenetic styles – some resisted compaction and had high pre‐salt porosities; others contain compaction‐broken fossils and pressure‐solution seams. The uncompacted rocks, together with the difficulty of explaining how halite cement could enter the Dawson Bay after overlying bedded halites were deposited, suggest that halite cementation occurred early with only a few tens of metres of overburden. Early diagenetic compaction is suggested by the presence of unbroken, displacive skeletal halite crystals, which cross‐cut compaction structures, and by the difficulty of explaining how (1) later compaction could occur in halite‐cemented rocks and (2) how pore‐fluids could be expelled after surrounding rocks lost their permeability. The organic‐rich nature of many carbonates may explain why compaction was both early and extensive, but this explanation fails to explain how similar compaction developed in horizons with lower organic contents. Chemical compaction may also have been enhanced by aragonite dissolution during seawater evaporation or brine dilution. Early chemical compaction in Dawson Bay carbonates indicates that compaction in other carbonates need not signify deep burial diagenesis; neither can compaction be used indiscriminately to identify other diagenetic events as being of deep burial origin. Early halite cementation, as in the Dawson Bay Formation, preserves carbonates at early diagenetic stages and may thus preserve geochemical information unmodified by later diagenesis.