bluuebunny/crossref_metadata_2025 huggingface dataset:
Interferon‐γ and Interleukin‐12 Genes are Preferentially Expressed During Early Experimental African Trypanosomiasis and Suppressed by Denervation of the Spleen
Authors: Liu  , Ragaa  , Li  , Nuortio  , Mustafa  , Bakhiet
Published: March 2003

The cross talk between the central nervous system (CNS) and the immune system includes among others, the modulation of immune responses by the autonomic nervous system. Here, we investigated the effects of a splenic denervation on cytokine induction in early experimental African trypanosomiasis. Profiles of the cytokine mRNA expression for interleukin (IL)‐4, interleukin (IL)‐6, interleukin (IL)‐10, interleukin (IL)‐12, tumour necrosis factor (TNF)‐α, tumour necrosis factor (TNF)‐β, transforming growth factor (TGF)‐β and interferon (IFN)‐γ were examined at 4 h, 8 h and 12 h postinfection (p.i.), and in noninfected controls. Only IFN‐γ and IL‐12 were significantly expressed over noninfected controls. Already at 4 h p.i. both cytokines were expressed and showed more increased levels at 12 h. Sympathetic denervation of the spleen markedly reduced the mRNA expression for both IFN‐γ and IL‐12. Con A was used as a positive control and showed an enhanced mRNA expression, which was also suppressed by a splenic denervation. To demonstrate that the mRNA expression had resulted in a cytokine production, we looked for the protein level of IFN‐γ at 4 h p.i. by immunohistochemistry and found increased levels of IFN‐γ, which was also inhibited by the denervation. Sham‐operated animals exhibited similar responses as the nondenervated controls. Our data present for the first time very early kinetics for a cytokine gene expression during an experimental African trypanosomiasis. Furthermore, the data suggest a regulatory role for the autonomic nervous system on cytokine responses at both the mRNA and the protein levels.
Surface and Intracellular Interleukin‐2 Receptor Expression on Various Resting and Activated Populations Involved in Cell‐Mediated Immunity in Human Peripheral Blood
Authors: Hodge  , Hodge  , Flower  , Han
Published: March 2003

The kinetics of assembly of the high‐affinity interleukin‐2 receptor (IL‐2R)α/β/γ were investigated by studying intracellular and surface expression of IL‐2Rα, β and γ by T cells, monocytes and natural killer (NK) cells. IL‐2Rα and IL‐2Rγ were expressed by small numbers of resting T cells. These numbers increased following stimulation, to maximal expression at 48 h and 72 h, respectively. This observation was consistent with de novo synthesis of the receptor protein in response to the stimulus. The proportion of T cells producing IL‐2Rβ was smaller and up‐regulated later than the proportion of cells producing IL‐2Rα or IL‐2Rγ. IL‐2Rβ may therefore slow the assembly of the high‐affinity IL‐2R on T cells. A small number of resting NK cells expressed IL‐2Rα, both on the cell surface and intracellularly, but this increased over 72 h on stimulated NK cells. IL‐2Rβ was constitutively expressed, both on the cell surface and intracellularly, by monocytes and NK cells. An increased proportion of NK cells and monocytes produced IL‐2Rβ, 24 h and 4 h post‐stimulation, respectively. Maximal or plateau expression occurred at 72 h and 24 h post‐stimulation, for NK cells and monocytes, respectively. The early up‐regulation of intracellular IL‐2Rβ for monocytes may facilitate the up‐regulation of surface IL‐2Rβ, and early assembly of the high‐affinity IL‐2R, accelerating monocyte activation and function. High constitutive intracellular IL‐2Rγ expression (> 80%) in all types of leucocyte investigated, decreased over the 72 h following stimulation with a concurrent increase in surface expression. IL‐2Rγ was expressed by increased proportions of T cells, monocytes and NK cells, 4 h following stimulation. The intracellular storage of IL‐2Rγ may accelerate translocation to the cell surface after stimulation. The early translocation of IL‐2Rγ may reflect its usage as a signal transduction molecule by other cytokine receptors — IL‐4, IL‐7, IL‐9 and IL‐15. This study delineated the potential expression of the high‐affinity IL‐2Rα/β/γ on various stimulated leucocytes. The differential kinetics of assembly of the high‐affinity IL‐2Rα/β/γ on different leucocyte subsets suggests that IL‐2 may regulate the inflammatory cellular responses in a sequential manner, paralleling the timed expression of IL‐2Rα/β/γ on the monocytes, NK cells and T cells.
Allergen Induced mRNA Expression of Interleukin‐5, but Not of Interleukin‐4 and Interferon‐γ, in Peripheral Blood Mononuclear Cells Obtained Before the Pollen Season Predicts the Clinical Efficacy of Immunotherapy for Seasonal Allergic Rhinitis
Authors: Kakinoki  , Ohashi  , Nakai  , Washio  , Nasako  , Tanaka  , Nakai
Published: March 2003

The primary aim of this study was to investigate whether the allergen‐induced synthesis of cytokines by peripheral blood mononuclear cells (PBMCs) obtained immediately before the pollen season could predict the clinical efficacy of immunotherapy during the following pollen season. PBMCs (1.0 × 106 cells/ml) were obtained from 17 nonatopic subjects and from 60 patients receiving immunotherapy for seasonal allergic rhinitis (caused by Japanese cedar pollens) immediately before the pollen season of 1998, and were cultured for 24 h in the presence of 10 mg/ml of Cry j 1, a major allergen of Japanese cedar pollens, at 37 °C in a fully humidified 5% CO2 atmosphere. Total cellular RNA was extracted from the PBMCs, and the allergen‐induced interleukin (IL)‐4, IL‐5 and interferon‐γ (IFN‐γ) mRNA expression was determined using a reverse transcription–polymerase chain reaction. According to the nasal symptoms during the pollen season of 1998, the 60 patients on immunotherapy were divided into 36 good responders (who had no nasal symptoms and no requirement for rescue medications) and 24 poor responders who needed rescue medications to control nasal symptoms. Neither IL‐4 mRNA nor IL‐5 mRNA was expressed in any of the 17 nonatopic individuals. By contrast, IL‐4 mRNA was expressed in 26 good responders and in 22 poor responders, and IL‐5 mRNA was expressed in eight good responders (22.2%) and in 23 poor responders (95.8%). IFN‐γ mRNA was expressed in four nonatopic subjects, in nine good responders and in seven poor responders. The expression of IFN‐γ did not differ significantly among the nonatopic subjects, the good responders and the poor responders. The mRNA expression of IL‐5 (P < 0.0001), but not of IL‐4 (P = 0.0999) and IFN‐γ (P = 0.7713), differed significantly between the good and poor responders. Therefore, our study has highlighted that positive expression of IL‐5 mRNA in PBMCs sampled immediately before the pollen season could be predictive of a poor clinical outcome of immunotherapy during the following pollen season and that the down‐regulation of IL‐5 mRNA expression in PBMCs could be an important mechanism of pollen immunotherapy related to the clinical efficacy.
Human Intestinal Endothelium Shows High Susceptibility to Cytomegalovirus and Altered Expression of Adhesion Molecules after Infection
Authors: Sindre  , Haraldsen  , Beck  , Hestdal  , Kvale  , Brandtzæg  , Degré  , Rollag
Published: March 2003

Human cytomegalovirus (HCMV) causes gastro intestinal disease with ulcerations, apparently as a consequence of cytopathic damage to endothelial cells (EC) and subsequent microvascular obliteration. In this study we showed that cultured human intestinal microvascular endothelial cells (HIMEC) are much more susceptible to HCMV infection than human umbilical vein endothelial cells (HUVEC). When both cell types were challenged with a clinical isolate of HCMV (10 pfu per cell), 30% of HIMEC expressed HCMV immediate early proteins, but only 10% of HUVEC. Enhanced susceptibility was also reflected in the expression of early and late HCMV proteins. In addition, the interleukin‐1β (IL‐1β)‐induced cellular expression of adhesion molecules differed between HIMEC and HUVEC after HCMV‐infection. E‐selectin was unaffected in HUVEC but increased in HIMEC, whereas vascular cell adhesion molecule (VCAM)‐1 was increased in HUVEC but decreased in HIMEC. Furthermore, HCMV‐infection enhanced the expression of intercellular adhesion molecule (ICAM)‐1 in both cell types. In conclusion, the enhanced susceptibility to HCMV infection observed in HIMEC and the elevated expression of E‐selectin and ICAM‐1 observed in these cells may provide an indication to the liability of developing gastrointestinal HCMV disease and may have a possible relevance to the survival of intestinal transplants.
Autoantibodies to Cryptic Epitopes Elicited by Infection with Lactate Dehydrogenase‐Elevating Virus
Authors: Gómez  , Coutelier  , Mathieu  , Lustig  , Retegui
Published: March 2003

Lactate dehydrogenase‐elevating virus (LDV) produces a permanent infection in mice with a B‐lymphocyte polyclonal activation leading to hypergammaglobulinaemia. Since LDV specifically suppressed antibodies to native epitopes in CBA/Ht, but not BALB/c, mice immunized against a protein antigen, we explored the relationship between such a change in antibody specificity and the expression of autoantibodies under the influence of LDV. Again in CBA/Ht, but not BALB/c, mice we observed another effect of LDV: the sera from infected CBA/Ht mice were found by enzyme‐linked immunosorbant assay to contain antibodies to various mouse tissue extracts. Immunoblots revealed a large spectrum of autoantigens that differed markedly between animals. Western‐blot competition experiments showed that the protein autoantigens had to be denatured to react with most of the autoantibodies. Despite the presence of these autoantibodies directed to cryptic epitopes, no specific tissue lesions could be ascribed to the autoimmune response elicited by LDV infection, since both mouse strains showed mild inflammatory reactions in liver and kidney.
Recruitment of SHP‐1 Protein Tyrosine Phosphatase and Signalling by a Chimeric T‐Cell Receptor–Killer Inhibitory Receptor
Authors: Christensen  , Geisler
Published: March 2003

Receptors expressing the immunoreceptor tyrosine‐based inhibitory motif (ITIM) in their cytoplasmic tail play an important role in the negative regulation of natural killer and B‐cell activation. A subpopulation of T cells expresses the ITIM containing killer cell inhibitory receptor (KIR), which recognize MHC class I molecules. Following coligation of KIR with an activating receptor, the tyrosine in the ITIM is phosphorylated and the cytoplasmic protein tyrosine phosphatase SHP‐1 is recruited to the ITIM via its SH2 domains. It is still not clear how SHP‐1 affects T‐cell receptor (TCR) signalling. In this study, we constructed a chimeric TCR–KIR receptor. We demonstrated that SHP‐1 is recruited to the chimeric TCR–KIR receptor following T‐cell stimulation with either anti‐TCR monoclonal antibody (MoAb) or superantigen. However, in spite of this we could not detect any effect of SHP‐1 on TCR signalling regarding total protein tyrosine phosphorylation, TCR down‐regulation, mobilization of intracellular free calcium, or induction of the activation markers CD69 and CD25.
Characterization of Murine Dendritic Cells Derived from Adherent Blood Mononuclear Cells In Vitro
Authors: Agger  , Petersen  , Toldbod  , Holtz  , Dagnæs‐Hansen  , Johnsen  , Bolund  , Hokland
Published: March 2003

The therapeutic potential of dendritic cells loaded with tumour antigens for the induction of effective immune responses against cancer is currently being tested in numerous clinical trials. In most cases, the dendritic cells are generated in vitro from peripheral blood monocytes. Many aspects of dendritic cell‐based vaccination have not yet been examined in detail, and homologous mouse model systems may prove very valuable for optimizing clinical procedures. In the murine system, however, dendritic cells are usually isolated from either lymphoid tissues or bone marrow cultures. To date, murine monocyte‐derived dendritic cells have been described only sporadically. Here, we describe a culture system for the generation of murine dendritic cells from adherent peripheral blood mononuclear cells by culturing in the presence of granulocyte‐macrophage colony stimulating factor and interleukin‐4. After 7 days of culture the nonadherent cells were harvested from the cultures. Most of these cells exhibited well‐accepted characteristics of mature dendritic cells (e.g. veiled appearance, high expression of major histocompatibility complex class II and CD86) and stimulated vigorous proliferation of allogeneic T cells in a primary mixed leucocyte reaction following stimulation with bacterial lipopolysaccharide. Interestingly, staining the cells for expression of the putative antigen‐uptake receptor DEC‐205 revealed a distinct bimodal distribution.
Role of J Chain in Secretory Immunoglobulin Formation
Authors: Johansen  , Braathen  , Brandtzaeg
Published: March 2003

The joining (J) chain is a small polypeptide, expressed by mucosal and glandular plasma cells, which regulates polymer formation of immunoglobulin (Ig)A and IgM. J‐chain incorporation into polymeric IgA (pIgA, mainly dimers) and pentameric IgM endows these antibodies with several salient features. First, a high valency of antigen‐binding sites, which makes them suitable for agglutinating bacteria and viruses; little or no complement‐activating potential, which allows them to operate in a noninflammatory fashion; and, most importantly, only J‐chain‐containing polymers show high affinity for the polymeric Ig receptor (pIgR), also known as transmembrane secretory component (SC). This epithelial glycoprotein mediates active external transfer of pIgA and pentameric IgM to exocrine secretions. Thus, secretory IgA (SIgA) and SIgM, as well as free SC, are generated by endoproteolytic cleavage of the pIgR extracellular domain. The secretory antibodies form the ‘first line’ of defence against pathogens and noxious substances that favour the mucosae as their portal of entry. The J chain is involved in creating the binding site for pIgR/SC in the Ig polymers, not only by determining the polymeric quaternary structure but apparently also by interacting directly with the receptor protein. Therefore, both the J chain and the pIgR/SC are key proteins in secretory immunity.
Spontaneous Apoptosis of Neutrophils in Whole Blood and its Relation to Apoptosis Gene Proteins
Authors: Majewska E. , Sulowska Z. , Baj Z.
Published: March 2003

Apoptosis of neutrophils limits their pro‐inflammatory potential. We tested the ability of fresh and cultured whole blood neutrophils to undergo spontaneous apoptosis and expression of p53, Fas/Apo‐1, bcl‐2 protein in the cells using flow cytometry. Neutrophil apoptosis was estimated using Annexin V and propidium iodide binding and verified under light microscopy. The percentage of early and late apoptotic neutrophils in the blood samples increased significantly after 20 h culture from 12.3 ± 14.2% and 4.3 ± 4.2% to 39.5 ± 14% and 15.3 ± 9.6%, respectively. The majority of late apoptotic neutrophils had altered morphology in FSC/SSC dot plot compared to alive or early apoptotic neutrophils. Cultured neutrophils presented markedly lower expression of bcl‐2 protein compared to fresh blood cells: 211 ± 321 median of fluorescence intensity (MFI) and 787 ± 1152 MFI, respectively. The increased percentage of late apoptotic cells after culture paralleled the increase in the Fas/Apo‐1 expression and negatively correlated with bcl‐2 expression. We noted intracellular expression of p53 protein in neutrophils, although the expression did not correlate neither to the percentage of the apoptotic neutrophils, nor to the Fas/Apo‐1 or bcl‐2 expression. Our results suggested that neutrophil apoptosis is gene regulated, moreover, we present a possibility to assess the neutrophil apoptosis and cellular expression of the proteins of apoptosis related genes in whole blood samples.
The Phenotypic Heterogeneity of Human Natural Killer Cells: Presence of at least 48 Different Subsets in the Peripheral Blood
Authors: Jonges L. E. , Albertsson P. , Van Vlierberghe R. L. P. , Ensink N. G. , Johansson B. R. , Van De Velde C. J. H. , Fleuren G. J. , Nannmark U. , Kuppen P. J. K.
Published: March 2003

Peripheral blood natural killer (NK) cells are usually defined as a homogeneous cell population. However, NK cells show heterogeneous expression of a diversity of cell surface molecules, which might reflect the diversity of NK‐cell functions. Therefore, a more specific phenotypic definition of NK cells is necessary. In this study, we made an inventory of phenotypic subsets that are present within the peripheral blood NK‐cell population of healthy donors based on differential expression of nine cell‐surface markers. Using three‐colour flow cytometric analysis we were able to define at least 48 different CD56+ NK‐cell subsets within the peripheral blood. This phenotypic heterogeneity appeared to be stable among healthy individuals, and was also steady within CD56dim and CD56bright NK populations, indicating a possible role for these subsets in NK‐cell function or differentiation.
Circulating TNF‐α, TGF‐β, and IL‐10 in Tuberculosis Patients and Healthy Contacts
Authors: Olobo J. O. , Geletu M. , Demissie A. , Eguale T. , Hiwot K. , Aderaye G. , Britton S.
Published: March 2003

Levels of tumour necrosis factor (TNF)‐α, transforming growth factor (TGF)‐β, and interleukin (IL)‐10 in plasma of pulmonary tuberculosis (TB) patients and healthy contacts and plasma and pleural fluid of patients with tuberculous pleuritis were examined by enzyme immunoassay. Plasma TNF‐α and IL‐10 were elevated to significant levels in healthy contacts. High levels of TGF‐β and IL‐10 were also detected in plasma from TB patients and healthy contacts. Pleural fluid contained all three cytokines with the level of IL‐10 being highest followed by TGF‐β and TNF‐α. Plasma of tuberculous pleuritis patients also had detectable levels of the three cytokines. Increased levels of TNF‐α in plasma of contacts and to some extent pleural fluid of pleuritis patients, is perhaps to limit the infection, while elevated IL‐10 in plasma of TB patients and contacts and pleural fluid would perhaps modulate excess proinflammation. Elevated TGF‐β in TB patients suggests its role in the immunopathogenesis.
Characterization of the Early Antibody Response in Bovine Tuberculosis: MPB83 is an Early Target with Diagnostic Potential
Authors: Mcnair J. , Corbett D. M. , Girvin R. M. , Mackie D. P. , Pollock J. M.
Published: March 2003

A 26‐kDa antigen has been shown to be a dominant antibody target in Mycobacterium bovis‐infected cattle. In this study, that antigen was used as an immunogen to raise a panel of mouse monoclonal antibodies. The majority of those bound to native protein with a molecular mass of 26 kDa and to recombinant MPB83, strongly suggesting that MPB83 is an important B‐cell antigenic target in bovine tuberculosis. In order to provide assessment of the potential of measuring antibody responses to the native protein, one monoclonal antibody, 1F11, was incorporated into an enzyme‐linked immunosorbant assay format to trap antigen from a crude bacterial extract. Despite some disadvantages of this format, serum samples from cattle which had been infected experimentally with M. bovis, and from tuberculin skin‐test‐negative and ‐positive field cattle were tested for the presence of antibodies. Data from the skin‐test‐negative cattle allowed an arbitrary cut‐off value to be established and, under these conditions, test sensitivity and specificity were estimated at 37.5 and 89%, respectively. These results indicate potential for MPB83 in the development of assays for serological diagnosis of bovine tuberculosis.
Immunomodulation Using Bacterial Enterotoxins
Authors: Simmons C. P. , Ghaem‐Magami M. , Petrovska L. , Lopes L. , Chain B. M. , Williams N. A. , Dougan G.
Published: March 2003

Immunologic unresponsiveness (tolerance) is a key feature of the mucosal immune system, and deliberate vaccination by a mucosal route can effectively induce immune suppression. However, some bacterial‐derived proteins, e.g. cholera toxin and the heat labile toxin of Escherichia coli, are immunogenic and immunomodulatory at mucosal surfaces and can effectively adjuvant immune responses to codelivered bystander antigens. This review summarizes some of the structural and biological characteristics of these toxins and provides examples of how these properties have been exploited for tolerance induction and mucosal vaccine development.
Inhibition of Dipeptidyl Peptidase IV (DP IV, CD26) Activity Abrogates Stress‐Induced, Cytokine‐Mediated Murine Abortions
Authors: Hildebrandt M. , Arck P. C. , Kruber S. , Demuth H.‐U. , Reutter W. , Klapp B. F.
Published: March 2003

In the CBA × DBA/2 mouse model, stress‐triggered abortions are mediated by a Th1‐like cytokine response of decidual lymphocytes. The factors that determine the cytokine pattern leading to abortion are currently unknown. Dipeptidyl Peptidase IV (DP IV) enhances Th1‐cytokine responses and impairs the evolvement of a Th2 cytokine profile. The T‐cell‐activation antigen, CD26, possesses DP IV activity. The aim of the present study was to investigate the role of DP IV activity and CD26‐positive decidual lymphocytes in murine stress‐triggered abortions by inhibition of DP IV activity. DBA/2‐mated CBA mice were stressed on day 5.5 of pregnancy and received daily injections of an inhibitor of DP IV activity, Ile‐thiazolidide (20 µmol/kg). On day 13 of gestation, the animals were sacrificed and the percentage of implants and abortions documented. CD26‐positive lymphocytes in spleen and uterine decidua and the intracellular cytokines interferon (IFN)‐γ and interleukin (IL)‐10 were determined by flow cytometry. Stressed and nonstressed animals receiving an inactive stereoisomeric form were used as controls. In mice receiving the DP IV inhibitor, stress failed to boost the abortion rate (37.2% versus 13.6%, P < 0.01). IFN‐γ producing cells were increased in stressed animals, but returned to the baseline upon the inhibition of DP IV. The number of IL‐10 producing cells was reduced in stressed animals, independent from DP IV inhibition.
Cytokine Polymorphisms in Systemic Lupus Erythematosus and Sjögren's Syndrome
Authors: Magnusson V. , Nakken B. , Bolstad A. I. , Alarcón‐Riquelme M. E.
Published: March 2003

Systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS) are defined genetically as complex diseases where multiple genes are involved in their pathogenesis. Among the genes of interest are those coding for the cytokines, molecules involved in immunoregulation that have been shown to play important roles in these diseases. Whether abnormalities in cytokine production are owing to genetic polymorphisms within the genes themselves is a matter of intensive study. The finding of functional polymorphisms within cytokine genes and their potential association with disease will open new avenues in their treatment.
Langerhans Cells and T Cells in Oral Graft versus Host Disease and Oral Lichen Planus
Authors: Hasséus B. , Jontell M. , Brune M. , Johansson P. , Dahlgren U. I.
Published: March 2003

Chronic graft versus host disease (cGVHD) of the oral mucosa, following allogeneic stem cell transplantation, and oral lichen planus (OLP) are both mucosal diseases where the immune system is involved in the pathogenesis. Although the aetiology of the two conditions is different, they present with a similar clinical appearance. This study compares the two diseases regarding the distribution of cells, which are expressing cell surface markers of interest for inflammatory responses. Monoclonal antibodies (MoAbs) were used in standard immunohistochemical procedures. CD1a+, CD80+ and CD86+ cells in the epithelium of OLP‐ and cGVHD lesions had the dendritic morphology of Langerhans cells (LC). Higher frequencies of CD1a+ LC as well as CD25+ cells were observed in the OLP epithelium than in the cGVHD epithelium. The OLP lesions showed higher frequencies of subepithelial cells expressing CD1a, CD86, CD4, CD8 and CD25 than the cGVHD lesions. Notably there was a significantly higher frequency of CD25+ cells in the epithelium and the connective tissue of OLP than in cGVHD. These cells might represent regulatory T cells. In conclusion, cGVHD and OLP show marked differences at the cellular level despite similar clinical appearance. Hence, the findings indicate differences in the regulation of the inflammatory response between the two conditions.
Idiopathic Membranous Glomerulonephritis Is Associated with Altered Patterns of Self‐reactive IgM and IgG Antibody Repertoires
Authors: Stahl D. , Venetz J.‐P. , Lacroix‐Desmazes S. , Rondeau E. , Bonnin E. , Kazatchkine M. D. , Ronco P. , Kaveri S. V.
Published: March 2003

Idiopathic membranous glomerulonephritis (MGN) is an immune complex nephropathy characterized by the subepithelial deposition of immunoglobulin (Ig)G. The pathogenesis of the disease remains largely unknown, but recent evidence suggests that human MGN may involve an autoimmune component. In the present study, we have analyzed the IgM and IgG antibody repertoires of patients with MGN towards self‐ and nonself‐antigens using a technique of quantitative immunoblotting on a panel of whole human tissue or solubilized bacterial cell extracts as sources of antigens. Data were compared by means of multiparametric statistical analysis. We demonstrate that the antibody repertoires of self‐reactive IgM and IgG in plasma of patients with MGN exhibit significantly altered patterns of reactivity, as compared with those of healthy controls. In contrast, multiparametric statistical analysis does not discriminate the reactivity patterns of IgM and IgG in plasma of patients and healthy controls towards nonself antigens. These observations indicate that a failure in the regulation of physiological self‐reactivity is associated with immune complex nephropathy in MGN.
The Natural Killer Cell – Friend or Foe in Autoimmune Disease?
Authors: Flodström M. , Shi F.‐D. , Sarvetnick N. , Ljunggren H.‐G.
Published: March 2003

Autoimmune diseases are chronic conditions resulting from a loss of immunological tolerance to self‐antigens. Recent observations have supported an ever‐broader role for innate immune responses in directing and regulating adaptive immunity, including responses to self. This review summarizes recent findings supporting important functions of natural killer (NK) cells in regulating autoimmunity. A close survey of the current literature reveals multiple steps where NK cells can regulate inflammation and intervene in loss of self‐tolerance. Importantly, the findings also caution against inferring a similar role for NK cells in all autoimmune phenomena or during separate stages of the same disease. Indeed, NK cells may have different influences during the priming and the effector phases of disease. Hence, an increased understanding of the involvement of NK cells in inflammation and infection should provide new insights into the pathogenesis of autoimmune disease.
Covalent Coupling of Palmitate to Ovalbumin Inhibits and Blocks the Induction of Oral Tolerance*
Authors: Oliveira F. M. , Santos E. M. , Mota‐Santos T. A. , Ruiz‐De‐Souza V. , Gontijo C. M.
Published: March 2003

Oral tolerance is a phenomenon that may occur in animals exposed to soluble antigens for the first time by the oral route. In the present study, we show that oral tolerance against ovalbumin (Ova) can be obtained after intragastric administration of the antigen in the presence of free residues of palmitate. On the other hand, oral tolerance induction is blocked when the residues of palmitate are covalently bound to the antigen (Ova‐palmitate conjugates). We have also noticed that oral administration of Ova‐palmitate conjugates can boost and/or prime experimental animals for Ova‐specific cellular and humoral systemic immune responses. Oral treatment with the conjugates also induces the production of local secretory immunoglobulin A (IgA) as measured in intestinal washes. Furthermore, Ova‐palmitate given orally can inhibit oral tolerance induction by naïve Ova.
An Experimental Vaccine Expressing Wild‐Type p53 Induces Protective Immunity against Glioblastoma Cells with High Levels of Endogenous p53
Authors: BLASZCZYK‐THURIN M. , O I. , ERTL H. C. J.
Published: March 2003

Inoculation of mice with a recombinant vaccinia virus expressing the full‐length mouse wild‐type p53 protein (Vp53‐wt) was shown to induce partial protection against peripheral challenge with a mouse glioblastoma cell line, termed GL261, expressing high levels of nuclear, endogenous wild‐type p53. In vivo experiments with knockout (KO) mice and mice treated with depleting doses of antibodies specific to lymphocyte subsets revealed that vaccine efficacy depended on CD4+ and CD8+ T cells as well as on natural killer (NK) cells. Vp53‐wt virus‐vaccinated mice that failed to develop tumours upon challenge with a minimal tumourigenic dose of GL261 cells remained completely resistant to further challenge with increased doses of GL261 cells. The efficacy of the Vp53‐wt vaccine was improved by adding recombinant mouse interleukin‐12 (rIL‐12) as an adjuvant at the time of tumour challenge. The induction of T cells to p53 in Vp53‐wt virus‐immune mice was also demonstrated at the tumour site by immunochemistry and was further confirmed by a delayed‐type hypersensitivity response to the p53 protein, although in vitro experiments using splenocytes from vaccinated mice failed to demonstrate CD4+ or CD8+ T‐cell activity to p53.
Phagocyte Activation by Trp–Lys–Tyr–Met–Val–Met, Acting through FPRL1/LXA4R, is not Affected by Lipoxin A4
Authors: Christophe T. , Karlsson A. , Rabiet M.‐J. , Boulay F. , Dahlgren C.
Published: March 2003

Lipoxin A4 (LXA4) has been shown to bind to the leucocyte formyl peptide receptor (FPR) homologue, FPRL1, without triggering the biological activities induced by other FPRL1 agonists. We investigated the direct effect of LXA4 as well as the effect on agonist‐induced biological responses using transfected HL‐60 cells expressing FPR, FPRL1 or FPRL2. LXA4 neither induced an intracellular rise in calcium in these transfectants nor affected the response induced by the peptide Trp–Lys–Tyr–Met–Val–Met (WKYMVM), an agonist that activates cells through FPRL1 and ‐2. Both agonists induced Erk‐2 activation; however, the eicosanoid‐induced activity was independent of FPRL1 and FPRL2. Moreover, LXA4 was unable to trigger neutrophil upregulation of complement receptor 3 and respiratory burst, and it had no effect on the responses induced by triggering with WKYMVM. We conclude that LXA4 is unable to affect the WKYMVM‐induced signalling through FPRL1 and suggest that it acts through a receptor different from FPRL1.
In Vitro Production and Characterization of Partly Assembled Human CD3 Complexes
Authors: Kastrup J. , Pedersen L. Ø. , Dietrich J. , Lauritsen J. P. H. , Menné C. , Geisler C.
Published: March 2003

Pairwise assembly of human CD3 chains takes place in the endoplasmic reticulum of T cells. Subsequently, the CD3 heterodimers form complexes with Tiα and Tiß chains forming hexameric TiαβCD3γεδε complexes. Finally, association with the ζ2 homodimer occurs in Golgi apparatus before the fully assembled T‐cell receptor is transported to the cell surface. To study the structural properties of the human CD3 chains, we have developed new methods to produce and fold the extracellular domains of CD3γ, CD3δ and CD3ε. Proteins were expressed in Escherichia coli as denatured chains and de novo folded in vitro. CD3γ and CD3ε folded as soluble monomers, whereas CD3δ did not yield any soluble proteins. When folding the chains pairwise, soluble CD3γε and CD3δε heterodimers could be isolated, whereas CD3γδ heterodimers were not produced. Using antibodies as structural probes, we identified two different types of antigenic epitopes that were dependent on heterodimerization. Our data indicate that CD3ε undergoes a conformational change after dimerization with CD3γ or CD3δ. Furthermore, we demonstrated that the CD3γε heterodimer could be purified using immunoaffinity chromatography.
Sublethal Concentrations of Complement Can Effectively Opsonize Borrelia burgdorferi
Authors: Suhonen J. , Hartiala K. , Tuominen‐Gustafsson H. , Viljanen M. K.
Published: March 2003

The fate of borreliae invading a human may depend on the early innate response they induce. The interactions of human complement system and neutrophils with two strains of the Lyme borreliosis spirochete Borrelia burgdorferi were studied. Borrelia burgdorferi sensu stricto B31 (resistant to a 28% concentration of normal human serum (NHS)) and Borrelia garinii Bg Å218/98 (sensitive to 7% NHS) were examined. Both strains induced neutrophil oxidative burst in a complement‐dependent manner. B31 required the presence of 7% NHS, but Bg Å218/98 required the presence of only 0.7% NHS for optimal induction of the burst. At all concentrations of NHS, the proportion of the spirochetes with C3bi on their surfaces and the relative amount of C3bi bound per spirochete were larger with Bg Å218/98 than with B31. Bg Å218/98 was able to induce an oxidative burst, when provided with serum with blocked classical pathway of complement, whereas B31 required the presence of the classical pathway. We suggest a role for the opsonizing effect of complement in controlling borreliae that are either resistant to direct killing by complement or located in the compartments of the human body at sublethal concentrations of the same.
Mesenchymal Stem Cells Inhibit and Stimulate Mixed Lymphocyte Cultures and Mitogenic Responses Independently of the Major Histocompatibility Complex
Authors: Le Blanc K. , Tammik L. , Sundberg B. , Haynesworth S. E. , Ringdén O.
Published: March 2003

We aimed to study the effects of mesenchymal stem cells (MSCs) on alloreactivity and effects of T‐cell activation on human peripheral blood lymphocytes (PBLs) in vitro. MSCs were expanded from the bone marrow of healthy subjects. MSCs isolated from second to third passage were positive for CD166, CD105, CD44, CD29, SH‐3 and SH‐4, but negative for CD34 and CD45. MSCs cultured in osteogenic, adipogenic or chondrogenic media differentiated, respectively, into osteocytes, adipocytes or chondrocytes. MSC added to PBL cultures had various effects, ranging from slight inhibition to stimulation of DNA synthesis. The stimulation index (SI = (PBL + MSC)/PBL) varied between 0.2 and 7.3. The SI was not affected by the MSC dose or by the addition of allogeneic or autologous MSCs to the lymphocytes.

Suppression of proliferative activity was observed in all experiments after the addition of 10,000–40,000 MSCs to mixed lymphocyte cultures (MLCs). Lymphocyte proliferation was 10–90%, compared with a control MLC run in parallel without MSCs. In contrast, the addition of fewer MSCs (10–1000 cells) led to a less consistent suppression or a marked lymphocyte proliferation in several experiments, ranging from 40 to 190% of the maximal lymphocyte proliferation in control MLCs. The ability to inhibit or stimulate T‐cell alloresponses appeared to be independent of the major histocompatibility complex, as results were similar using ‘third party’ MSCs or MSCs that were autologous to the responder or stimulating PBLs. The strongest inhibitory effect was seen if MSCs were added at the beginning of the 6 day culture, and the effect declined if MSCs were added on day 3 or 5. Marked inhibitory effects of allogeneic and autologous MSCs (15,000) were also noted after mitogenic lymphocyte stimulation by phytohaemagglutinin (median lymphocyte proliferation of 30% of controls), Concanavalin A (56%) and protein A (65%). Little, if any, inhibition occurred after stimulation with pokeweed mitogen. Low numbers of MSCs (150 cells) were unable to inhibit mitogen‐induced T‐cell responses.

MSCs have significant immune modulatory effects on MLCs and after mitogenic stimulation of PBL. High numbers of MSCs suppress alloreactive T cells, whereas very low numbers clearly stimulated lymphocyte proliferation in some experiments. The effect of a larger number of MSCs on MLCs seems more dependent on cell dose than histocompatibility and could result from an ‘overload’ of a stimulatory mechanism.
The Chemokines CCL5, CCL2 and CXCL12 Play Significant Roles in the Migration of Th1 Cells into Rheumatoid Synovial Tissue
Authors: Shadidi K. R. , Aarvak T. , Henriksen J. E. , Natvig J. B. , Thompson K. M.
Published: March 2003

As the T‐cell population in the synovial tissue (ST) in rheumatoid arthritis (RA) is dominated by T helper (Th) 1 cells, this study was designed to examine whether there is a preferential migration of polarized T cells to ST, and to identify the chemokines responsible for the migration. This was done by developing 10 T‐cell clones specific for an arbitrary antigen (mouse immunoglobulin G (IgG)) from the peripheral blood (PB) of a healthy donor sensitized to mouse IgG. The Th polarizations of the clones were determined by measuring secreted interferon‐γ and interleukin‐4, following anti‐CD3 stimulation. Migration to pools of RA ST cell‐derived supernatants was analysed. Expression of the chemokine receptors CCR1, CCR2, CCR3, CCR4, CCR5, CCR6, CCR7, CCR8, CXCR3 and CXCR4 were analysed by flow cytometry. Th1 clones showed significantly higher migration to RA ST cell‐derived supernatant compared with Th2 clones. Blocking of either of the chemokines, CCL5 or CCL2, strongly inhibited migration of the Th1 cells between 56 and 77%, while blocking of CXCL12 inhibited migration between 44 and 61%. Blocking of CXCL10 had only a minor inhibitory effect. Our results demonstrate a selective migration of Th1 cells to RA ST supernatant and that blocking either CCL5, CCL2 or CXCL12 significantly inhibits T‐cell migration. This indicates that CCL5, CCL2 and CXCL12 play significant roles in attracting Th1 cells towards the RA ST, and may prove potent targets for obstructing T‐cell migration to the synovium.
Conditions of meteoric calcite formation along a Variscan fault and their possible relation to climatic evolution during the Jurassic–Cretaceous
Authors: MUCHEZ  , NIELSEN  , SINTUBIN  , LAGROU
Published: March 2003

Two calcite cements, filling karst cavities and replacing Lower Carboniferous limestones at the Variscan Front Thrust, were precipitated after mid‐Jurassic Cimmerian uplift and subsequent erosion but before late Cretaceous strike‐slip movement. The first calcite (stage A) is nonferroan and crystals are coated by hematite and/or goethite. These minerals also occur as inclusions along growth zones. The calcite lattice contains < 0·07 mol.% Fe, but Mn concentrations can be as high as 0·72 mol.% in bright yellow luminescent zones. Primary, originally one‐phase, all‐liquid, aqueous inclusions have a final melting temperature between −0·2° and +0·2 °C, indicating a meteoric origin of the ambient water. The δ13C and δ18O values of the calcites are between −7·3‰ and −6·3‰, −7·8‰ and −5·5‰ on the Vienna PeeDee Belemnite (VPDB) scale, respectively. The second calcite (stage B) consists of ferroan (0·13–0·84 mol.% Fe) blocky crystals with Mn concentrations between 0·34 and 0·87 mol.%. Primary, single‐phase aqueous fluid inclusions indicate precipitation from a meteoric fluid below 50 °C . The δ13C values of stage B calcites vary between −7·3‰ and −2·1‰ VPDB and the δ18O values between −7·9‰ and −7·2‰ VPDB. A precipitation temperature below 50 °C for the stage A calcites and the presence of iron oxide/hydroxide inclusions in the crystals indicate near‐surface precipitation conditions. Within this setting, the geochemistry of the nonferroan stage A calcites reflects precipitation under oxic to suboxic conditions. The ferroan stage B calcites precipitated in a reducing environment. The evolution from the stage A to stage B calcites and the associated geochemical changes are interpreted to be related to the change from semiarid to humid conditions in western Europe during late Jurassic–Cretaceous times. A change in humidity can explain the evolution of groundwater from oxic/suboxic to reducing conditions during calcite precipitation. The typically higher δ13C values of the stage B compared to the stage A calcites can be explained by a smaller contribution of carbon derived from soil‐zone processes than from carbonate dissolution in the groundwater under humid conditions. The small shift to lower δ18O between stage A and B calcites may be caused by a higher precipitation temperature or a decrease in the δ18O value of the meteoric water. This decrease could have been caused by a change in the source of the air masses or by an increase in the amount of rainfall during the early mid‐Cretaceous. Although the latter interpretation is preferred, it cannot be proven.
Postglacial colluvium in western Norway: depositional processes, facies and palaeoclimatic record
Authors: BLIKRA  , NEMEC
Published: March 2003

The postglacial Quaternary colluvial systems in western Norway are arrays of steep fans, often coalescing into aprons, developed along the slopes of valley sides and fjord margins. The coarse debris, derived from weathered gneissic bedrock and its glacial‐till mantle, varies from highly immature to mature. The depositional processes are mainly avalanches, ranging from rockfalls and debrisflows to snowflows, but include also waterflow and debris creep. The mechanics and sedimentary products of these processes are discussed, with special emphasis on snow avalanches, whose role as an agent of debris transport is little‐known to sedimentologists. The subsequent analysis of sedimentary successions is focused on colluvial‐fan deltas, which are very specific, yet little‐studied, coastal depositional systems. The stratigraphic variation and depositional architecture of the colluvial facies assemblages, constrained by abundant radiometric dates, are used to decipher the signal of regional climatic changes from the sedimentary record. The stratigraphic data from two dozen local colluvial successions are compiled and further compared with other types of regional palaeoclimatic proxy record. The analysis suggests that the colluvial systems, although dependent upon local geomorphic conditions, have acted as highly sensitive recorders of regional climatic changes. The study as a whole demonstrates that colluvial depositional systems are an interesting and important frontier of clastic sedimentology.
Formation and diagenesis of bedding cycles in uppermost Cretaceous chalks of the Dan Field, Danish North Sea
Authors: Scholle Peter A. , Albrechtsen Troels , Tirsgaard Henrik
Published: March 2003

Metre‐scale lithologic cycles, visible in core and on logs from Maastrichtian chalks of the Dan Field, were examined to determine their mechanisms of deposition and relation to hydrocarbon production. The lower parts of cycles consist of porous, cream‐coloured, largely non‐stylolitic, commonly laminated chalk with limited bioturbation (mainly escape burrows). Cycles are capped by thinner intervals of white to grey, hard, stylolitic chalk with concentrations of bioclastic material, intense burrowing and few preserved primary sedimentary structures. The cycle caps contain nearly twice as much Mg as compared to the more porous parts of cycles and also have slightly larger δ18O values (−4·1‰ for the caps; −4·4‰ for porous zones). There is a significant reduction of average cycle thickness, as well as total thickness of the Maastrichtian chalk section, from SW to NE across the Dan Field. The cycle thinning largely results from a reduced thickness of porous chalks from the lower parts of cycles and thus is reflected in lower average porosity and permeability on the NE side of the field. These data indicate that episodic winnowing removed fine‐grained constituents from highstanding northeastern areas. Porous cycle bases were deposited at relatively high rates that precluded complete bioturbation; preserved laminae, coupled with escape burrows, reflect episodic sediment influx in areas that flank the seafloor highs. Cycle tops apparently accumulated more slowly (throughout the region, but especially on seafloor highs), perhaps because of reduced productivity of planktic organisms. Slower sedimentation allowed more complete bioturbation and destruction of sedimentary structures, and also led to incipient high‐magnesium calcite seafloor cementation (sufficient to yield firmer sediment and enhanced burrow preservation, but not to form true hardgrounds). Thus, the elevated magnesium contents and reduced porosity of the cycle caps reflect very early diagenetic processes that were only partially modified by burial diagenesis.

Rates of chalk deposition, as inferred from physical and geochemical evidence, appear to be a significant control on reservoir characteristics in North Sea chalks. The highest average porosities and permeabilities are found in areas with the highest sediment accumulation rates where seafloor diagenesis is minimized. Topographic depressions at the time of sedimentation can thus be expected to have the best production characteristics, and synsedimentary topographic highs should have the thinnest sections and the poorest petrophysical properties.
Facies architecture and geometry of landward‐stepping shoreface tongues: the Upper Cretaceous Cliff House Sandstone (Mancos Canyon, south‐west Colorado)
Authors: Olsen Tina R. , Mellere Donatella , Olsen Torben
Published: March 2003

The Campanian Cliff House Formation represents a series of individually progradational shoreface tongues preserved in an overall landward‐stepping system. In the Mancos Canyon area, the formation consists of four, 50‐ to 55‐m‐thick and 10‐ to 20‐km‐wide sandstone tongues, which pinch out landwards into lower coastal plain and lagoonal deposits of the Upper Menefee Formation and seawards into offshore shales of the Lewis Shale Formation. Photogrammetric mapping of lithofacies along the steep and well‐exposed canyon walls was combined with sedimentary facies analysis and mapping of the detailed facies architecture. Two major facies associations have been identified, one comprising the mostly muddy and organic‐rich facies of lagoonal and lower coastal plain origin and one comprising the sandstone‐dominated facies of shoreface origin. Key stratigraphic surfaces were identified by combining the mapped geometry of the lithofacies units with the interpretation of depositional processes. The stratigraphic surfaces (master ravinement surface, shoreface/coastal plain contact, transgressive surface, maximum flooding surface and the sequence boundary) allow each major sandstone tongue to be divided into a simple sequence, consisting of a basal transgressive system tract (TST) overlain by a highstand system tract (HST). Within each sandstone tongue, a higher frequency cyclicity is evident. The high‐frequency cycles show a complex stacking pattern development and are commonly truncated in the downdip direction by surfaces of regressive marine erosion. The complexities of the Cliff House sandstone tongues are believed to reflect changes in the rate of sea‐level rise combined with the responses of the depositional system to these changes. Synsedimentary compaction, causing a thickness increase in the sandstone tongues above intervals of previously uncompacted lagoonal/coastal plain sediments, also played a role. This study of the facies architecture, geometry and sequence stratigraphy of the Cliff House Formation highlights the fact that there may be some problems in applying conventional sequence stratigraphical methods to landward‐stepping systems in general. These difficulties stem from the fact that no single stratigraphic surface can easily be identified and followed from the non‐marine to the fully marine realm (i.e. from the landward to the basinward pinch‐out of the sandstone tongues). In addition, the effects of synsedimentary compaction and changes in the shoreface dynamics are not easily recognized in limited data sets such as from the subsurface.