bluuebunny/crossref_metadata_2025 huggingface dataset:
The Specificity of Synovial IgM Rheumatoid Factors (RF) for Genetically Engineered IgG Antibodies is not Affected by the Method used to Immortalize RF‐Producing B Cells
Authors: BONAGURA  , KWONG  , KENNY  , ROBBINS  , MORRISON
Published: March 2003

Previously, we have shown that some rheumatoid factors (RFs) produced by Epstein–Barr virus (EBV)‐transformed B cells from patients with rheumatoid arthritis (EBV‐RA‐RF) appear to be disease‐specific autoantibodies that bind differently to defined epitopes on genetically engineered IgG antibodies, compared with RFs expressed by patients with Waldenström's macroglobulinaemia (Wmac‐RFs) and healthy immunized donors (HID‐RFs). To exclude the possibility that EBV transformation is responsible for these differences, we have now studied 15 other monoclonal IgM RFs from patients with RA that were produced by heterohybridoma–B‐cell fusion (HRA‐RFs). These HRA‐RFs show the same gross specificity profiles for IgG as do their EBV‐RA‐RF counterparts. However, when the specificities of the HRA‐RF and EBV‐RA‐RF panels were combined and compared with those RFs from patients with Wmac or HID, significant differences in binding specificity were again observed. Hybrid IgG3/4 antibodies made by exon shuffles between the IgG3 and IgG4 wild‐type genes, and families of IgG variant antibodies made by site‐directed mutagenesis, were used to map the fine specificity of HRA‐RFs. The fine specificity of HRA‐RFs were also similar to those of EBV‐RA‐RFs. These studies demonstrate that the method used for immortalizing IgM, RF‐producing B cells from RA patients does not influence the specificity of the RFs obtained. Furthermore, some RFs expressed in RA have distinct and unique specificities, and may therefore represent disease‐specific autoantibodies.
Altered Pattern of Connectivity in Serum Immunoglobulins from Pemphigus Vulgaris Patients
Authors: PACHECO‐GARCÍA  , TOVAR‐RIVERA  , PADIERNA‐OLIVOS  , ROJAS‐ESPINOSA  , SÁNCHEZ‐COLÓN  , GUTIÉRREZ‐ARMENTA  , RIVERA‐BENÍTEZ  , MASSO‐ROJAS  , SÁNCHEZ‐GARCÍA
Published: March 2003

Pemphigus vulgaris is a cutaneous autoimmune disease in which the occurrence of autoantibodies directed against desmoglein‐3 and other self‐antigens has been well established in patient sera. However, V‐region interactions (connectivity) of serum IgG and IgM have not been analysed to date. In this report, it has been demonstrated that IgG and IgM in the sera of pemphigus vulgaris patients bind a preparation of F(ab′)2 fragments fractionated according to their isoelectric points, and that a pattern of connectivity distinguishable from that of healthy donor sera arises when the sera are tested against 20 individual isoelectric‐focusing‐separated F(ab′)2‐containing fractions. This suggests that there are alterations in regulatory networks. In spite of the fact that prednisolone‐based treatment of pemphigus patients has proved to be effective in controlling the disease, some undesirable effects associated with this form of treatment have prompted investigation into other therapeutic approaches. One possible approach to the treatment of this autoimmune disease is the use of high doses of normal polyclonal immunoglobulins. In fact there are a few reports of the empirical intravenous administration of immunoglobulins to pemphigus vulgaris patients. The results presented here provide the rational basis for using such a treatment, since it is demonstrated that a deviation from healthy V‐region interactions can be attributed to pemphigus patients and that such a condition is considered to be modified by this type of immunotherapy.
Regulation of Complement Factor H in a Human Liver Cell Line by Interferon‐γ
Authors: Luo  , Vik
Published: March 2003

Factor H is a regulatory protein of the alternative pathway of complement activation. The liver is the major site of synthesis. We have used the Hep3b human liver cell line as a model for examining its regulation by interferon‐γ (IFN‐γ). The maximal response was achieved at 50 U/ml of IFN‐γ. An increase in H mRNA was observed as early as 2 h after addition of IFN‐γ; the response peaked at 24 h. The half‐life of H mRNA in the presence of IFN‐γ was 3.8 ± 0.8 h. The increase in H mRNA by IFN‐γ was partly dependent on protein synthesis, as cycloheximide (CHX) reduced the response by 40% and the level of H mRNA decreased in a dose‐dependent manner with increasing concentrations of CHX. Phosphorylation events were also important in this induction because the kinase inhibitors staurosporine and genistein inhibited the induction of H mRNA by 88% and 68%, respectively. The induction could be inhibited completely when Hep3b cells were treated with CHX and staurosporine. Thus induction of factor H by IFN‐γ apparently involves two factors. One is likely to be Stat1α and the other is a CHX‐sensitive protein.
Immunological Changes in Human Immunodeficiency Virus (HIV)‐Infected Individuals During HIV‐Specific Protease Inhibitor Treatment
Authors: Ullum  , Katzenstein  , Aladdin  , Nielsen  , Søndergaard  , Gerstoft  , Skinhøj  , Pedersen
Published: March 2003

The present study examines the influence of effective anti‐retroviral treatment on immune function, evaluated by a broad array of immunological tests. We followed 12 individuals infected with human immunodeficiency virus (HIV) for 6 months after initiation of combination anti‐retroviral treatment including a protease inhibitor. Unstimulated and pokeweed mitogen (PWM)‐, interleukin (IL)‐2‐ and phytohaemagglutinin (PHA)‐stimulated lymphocyte proliferative responses increased during follow‐up reaching average levels from 1.3‐fold (PHA) to 3.7‐fold (PWM) above baseline values. The total CD4+ lymphocyte count increased mainly due to increases in numbers of CD4+ CD28+ and CD4+ CD45RO+ cells, whereas increases in numbers of CD4+ CD45RA+ cells contributed little to the increase in CD4+ cell count. The total cytotoxic T‐cell (CTL) killing of autologous B cells infected with HIV‐encoding recombinant Vaccinia virus was increased after 3–6 months, whereas the specific HIV‐directed CTL activity and the concentration and lytic activity of natural killer (NK) cells were unchanged during follow‐up. These results demonstrate that the initiation of a treatment including an HIV protease inhibitor is followed by an increase in lymphocyte proliferation and lymphocyte‐mediated cytotoxicity. However, unchanged levels of specific HIV CTL and NK cell activity warn us that not all measures of immune function may respond simultaneously to anti‐retroviral treatment.
Expression of Activation and Costimulatory Elements by Human Intestinal Intraepithelial Lymphocytes
Authors: Sillett  , Southgate  , Howdle  , Trejdosiewicz
Published: March 2003

It is unclear whether human intestinal intraepithelial T lymphocytes (iIEL) are resting or activated cells. To address this question, an improved isolation procedure was developed for small bowel iIEL, which were analysed by two‐colour flow cytometry and compared with resting and mitogen‐activated peripheral blood lymphocytes. iIEL expression of CD44 isoforms, Bcl‐2 and Ki67 antigen was also determined in tissue sections. iIEL expressed CD69 at levels comparable with 48–72 h phytohaemagglutinin blasts, but did not express CD25 or CD95. iIEL were Bcl‐2+ but not Ki67+. αEβ7 and α4B7 expression was relatively high, whereas αLβ2, CD5 and CD28 were expressed at low density. Isolated iIEL expressed CD44 (core epitopes) at lower levels than peripheral blood lymphocytes, although almost all CD44 contained splice variant 6 (CD44v6). Peripheral blood lymphocytes expressed CD44 at very high density, but little CD44v6, even after activation. However, in tissue sections, iIEL showed differential labelling with CD44 core epitope antibodies and no detectable CD44v6, implying CD44 receptor occupancy or epitope masking in situ. Thus, normal iIEL express a quasi‐activated phenotype with unusual patterns of adhesion receptors, which may act as costimulatory elements. These may permit iIEL to assume effector functions, with absence of CD25 preventing entry into the cell cycle, thereby maintaining an apoptosis‐resistant phenotype.
Costimulation of CD28− T Cells Through CD3 and β1‐Integrins Induces a Limited Th1 Cytokine Response
Authors: Saukkonen  , Tantri  , Berman
Published: March 2003

The costimulatory molecule CD28 regulates antigen‐specific T‐cell proliferation and the synthesis of multiple cytokines. The absence of CD28 on a subset of CD8bright+ T cells suggests that these cells may utilize alternative costimulatory pathways or have a limited cytokine response to presented antigen. We used fibronectin, a ligand for the β1‐integrins α4β1 and α5β1, as an alternate costimulatory ligand to assess the functional phenotype of CD8bright+CD28− T cells. CD25 expression was significantly up‐regulated in CD8bright+CD28− T cells by immobilized anti‐CD3i with fibronectin. Costimulation with fibronectin also significantly augmented anti‐CD3i‐induced IFN‐γ production only among CD8bright+CD28− T cells. The CD8bright+CD28− T cells did not produce significant IL‐2 and IL‐10 even in response to maximal stimulation with phorbol myristate acetate and ionomycin. These data support a costimulatory role for ß1‐integrins in CD8bright+CD28− T cells and indicate that CD8bright+ CD28− T cells have a restricted Th1 cytokine repertoire.
Increased Expression of Down‐Regulatory CTLA‐4 Molecule on T Lymphocytes from Rheumatoid Synovial Compartment
Authors: Liu  , Yang  , Li  , Lai  , Chao  , Lei
Published: March 2003

Since the CTLA‐4 molecule expressed on activated T lymphocytes has recently been suggested to be an important negative regulator in autoimmune diseases, this study was undertaken to investigate the expression and function of CTLA‐4 on synovial T cells from patients with rheumatoid arthritis. CTLA‐4‐expressing T cells were detected using a dual fluorescence flow cytometric method. Only a small percentage of peripheral blood T cells from patients with rheumatoid arthritis had detectable surface CTLA‐4 expression (mean ± SD, 1.89 ± 1.92%). However, the levels of CTLA‐4‐positive T cells was increased significantly in rheumatoid synovial fluids (5.44 ± 4.96%) and synovial membranes (28.76 ± 14.30%). To explore the role of CTLA‐4 molecule in the inflammation of rheumatoid joints, CTLA‐4 was blocked with anti‐CTLA‐4 antibody to assess its effects on the production of tumour necrosis factor α and interleukin 1β in synovial fluid mononuclear cell culture. The addition of anti‐CTLA‐4 antibody enhanced the production of tumour necrosis factor α and interleukin 1β in a dose‐dependent manner. The data suggest that the expression of CTLA‐4 plays a down‐regulatory role in rheumatoid articular inflammation. We thus concluded that CTLA‐4 was up‐regulated on synovial T cells from patients with RA, and the increased CTLA‐4 expression might exert a down‐regulation effect on tumour necrosis factor α and interleukin 1β production.
Alloreactive Cytotoxic T‐Cell Function, Peptide Nonspecific
Authors: MÜLLBACHER  , LOBIGS  , KOS  , LANGMAN
Published: March 2003

The recognition requirements necessary for murine alloreactive cytotoxic T‐cells to carry out their effector function has been investigated using target cells that express a unique class I major histocompatibility complex (MHC)‐peptide pair. The human cell line T2 and the murine cell line RMA‐S are defective in peptide transport components needed to effectively express stable MHC class I molecules at the cell surface. When T2 cells were infected with a vaccinia virus that encoded the Kd gene and provided with a Kd‐motif peptide from the nucleoprotein of influenza virus (NPP), these cells could be lysed by polyclonal allo Kd‐reactive cytotoxic T‐lymphocytes (CTL). Similar results were obtained with the murine RMA–S–Kd cell line, transfected with cDNA able to express some ‘empty’ Kd that is heat‐labile. Adding another Kd‐motif peptide from influenza virus haemagglutinin (HAP) stabilized the surface expression of Kd and allowed the RMA–S–Kd cells to be lysed before or after heat shock. At 27 °C anti‐Kd alloreactive CTL‐lysed target cells in the presence and absence of HAP peptide. Alloreactive CTL appear to have a more stringent requirement for a high density of MHC class I on cell surfaces relative to peptide‐specific MHC‐restricted CTL. We conclude that while Kd‐restricted CTL activity is strictly peptide‐specific, anti‐Kd‐specific alloreactivity is MHC allele‐specific, but peptide‐nonspecific. This conclusion is at odds with the Standard Model of T‐cell receptor (TCR) function, but consistent with the predictions of a Competing Model of TCR function.
Rapidity of Specific Antibody–Antigen Interactions
Authors: Scicluna  , McCullough
Published: March 2003

Analysis of humoral immune responses against viruses has concentrated on studies with serum dilutions, which reflect characteristics pertaining to the diluent buffer but not the serum environment. The majority of virus‐specific antibody in serum from foot‐and‐mouth disease virus (FMDV)‐vaccinated cattle bound to antigen within 10–60 s, whereas aspecific reactions evolved more slowly. Upon dilution of sera, the reaction characteristics no longer related to those obtained with the serum, particularly when individual animals were compared. Diagnostic enzyme‐linked immunosorbent assay (ELISA) — employing diluted serum — identified little variation in the reactivity of serum samples from different vaccinated cattle. This related to previous analyses showing similar specific antibody titres. In contrast, analyses of serum reactivities over a 10‐ and 60‐s incubation period demonstrated high variation between individual animals. Furthermore, when a challenge infection was performed on vaccinated animals, only those with the higher serum reactivities over a 10‐ and 60‐s incubation were protected. These results demonstrate the importance of the specific serum antibody reactions, which will occur within seconds. Moreover, such qualitative characteristics would be overlooked when employing conventional assays with diluted sera and long incubation periods.
Collagen‐Bound α1‐Microglobulin in Normal and Healed Tissues and its Effect on Immunocompetent Cells
Authors: Santin  , Cannas
Published: March 2003

The mechanisms devoted to the protection of the extracellular matrix collagen from the inflammatory insult are not fully understood. We investigated the presence of the immunosuppressive glycoprotein α1‐microglobulin in healed tissues such as scars and periprosthetic membranes, comparing them with normal skin. Immunohistochemistry showed that α1‐microglobulin was mainly present along collagen fibrils and in the epidermis. The presence of this protein was confirmed by Western blot of the tissue homogenates, while ELISA showed lower levels in the healed tissues. In vitro, the purified α1‐microglobulin bound collagen by a cooperative mechanism and attenuated the collagen‐induced activation of the mononuclear cells.
A Single‐Chain Fusion Molecule Consisting of Peptide, Major Histocompatibility Gene Complex Class I Heavy Chain and β2‐Microglobulin Can Fold Partially Correctly, but Binds Peptide Inefficiently
Authors: Sylvester‐Hvid  , Nielsen  , Hansen  , Pedersen  , Buus
Published: March 2003

The function of major histocompatibility complex class I (MHC‐I) molecules is to sample peptides from the intracellular environment and present these peptides to CD8+ cytotoxic T lymphocytes (CTL). We have attempted to develop a general approach to produce large amounts of pure and active recombinant MHC‐I molecules. A convenient source of MHC‐I molecules would be a valuable tool in structural and biochemical analysis of MHC‐I, and in experiments using MHC‐I molecules to enable specific manipulations of experimental and physiological CTL responses. Here we describe the generation of a recombinant murine MHC‐I molecule, which could be produced in large amounts in bacteria. The recombinant MHC‐I protein was expressed as a single molecule (PepSc) consisting of the antigenic peptide linked to the MHC‐I heavy chain and further linked to human β2‐microglobulin (hβ2m). The PepSc molecule was denatured, extracted, purified and folded using a recently developed in vitro reiterative refolding strategy. This led to the formation of soluble, recombinant MHC‐I molecules, which migrated as monomers of the expected size when submitted to non‐reducing sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE). Serological analysis revealed the presence of some, but not all, MHC‐I‐specific epitopes. Biochemically, PepSc could bind peptide, however, rather ineffectively. We suggest that a partially correctly refolded MHC‐I has been obtained.
Tolerance or Rejection: A Delicate Balance as Judged by Exposure of Heart‐Transplanted Rats to the Immunomodulator Linomide®
Authors: Qi  , Tufveson  , Ekberg
Published: March 2003

When applied in rodent transplant models most immunosuppressive drugs yield adequate graft protection for as long as the drug is given, and permanent graft survival is often induced. The immunomodulator, Linomide®, previously shown to stimulate T cells and prevent apoptosis, usually reduces or abolishes both tolerance induction and the graft‐protective effect of the immunosuppressive drug. By chance, we observed that Linomide® alone exerted a modest but unequivocal graft‐protective effect in the BN to WF strain combination. This finding was analysed by simple genetic mapping of rat strains. Untreated WF recipients kept BN grafts for a median of 8 days, whereas Linomide® treatment prolonged graft survival to 12.5 days (P = 0.0001). In control groups (DA to LEW, BN to LEW, DA to WF and WF to BN), median graft survival was 5.5–7 days irrespective of whether Linomide® was given. However, the BN to F1 (LEW × WF) combination also manifested slightly longer graft survival in the presence of Linomide®. F1 (BN × WF) to WF grafts survived a median of 15 days without Linomide® and 46 days with Linomide® treatment. Both in the presence and absence of Linomide®, two of the control graft combinations [F1 (BN × DA) to WF and F1 (BN × WF) to BN] manifested 6–7‐day graft survival. Taken together, our results suggest a delicate balance between unresponsiveness and rejection, while a single agent (Linomide®) may either cause on its own long‐term survival of allografts in one setting or rejection despite optimal immunosuppression in another setting.
Glycosylation of Immunoglobulin A Influences Its Receptor Binding
Authors: Basset  , Devauchelle  , Durand  , Jamin  , Pennec  , Youinou  , Dueymes
Published: March 2003

Immunoglobulin A (IgA), which is heavily glycosylated, interacts with a variety of receptors, e.g. the asialoglycoprotein receptor (ASGP‐R), which binds terminal galactose residues, and the Fcα receptor (FcαRI). It has thus been proposed that elevated serum levels of IgA in primary Sjögren's syndrome (pSS) are caused by its defective clearance. To test this hypothesis, we developed a method (based on sialyl transferases eluted from a hepatoma cell line) to increase the amount of sialic acid (SA) on IgA, and used a battery of IgA1‐ and IgA2‐specific glycosidases to reduce this amount. Binding of IgA1 and IgA2 to ASGP‐R and FcαRI was found to be sugar dependent because oversialylated IgA bound less than native or desialylated IgA. However, individual sugars did not play a direct role in this binding. Given that IgA are oversialylated in pSS, defective clearance of IgA may indeed be ascribed to an excess of SA in IgA1 and IgA2.
Low Concentrations of Immunoglobulin G Antibodies to Salmonella Serogroup C in C2 Deficiency: Suggestion of a Mannan‐Binding Lectin Pathway‐Dependent Mechanism
Authors: Selander  , Weintraub  , Holmström  , Sturfelt  , Truedsson  , Mårtensson  , Jensenius  , Sjöholm
Published: March 2003

The influence of complement on immune responses to polysaccharides is debatable. We examined the serum concentrations of IgM and IgG antibody against Salmonella O‐antigen specific oligosaccharides representing the serogroups B, C and D, and against capsular polysaccharides of Streptococcus pneumoniae serotypes 6 and 23 in C2‐deficient adults and in healthy controls. A sharp contrast of findings was found for antibodies against the CO antigen, an activator of the mannan‐binding lectin (MBL) pathway of complement activation. The C2‐deficient group showed normal IgM and markedly low IgG antibody levels. Similar findings were made in adults with low concentrations of MBL. This suggests that the recruitment of classical pathway C3 convertase through the MBL pathway is critically involved in isotype switching of antibodies against MBL pathway activating antigens during immune system maturation. The findings imply a new role of the MBL pathway, and an additional link between innate and acquired immunity. Specific IgM against BO was moderately low in C2 deficiency. Other differences for the Salmonella antigens were not found. Markedly raised IgM antibody levels against pneumococcal polysaccharides in C2 deficiency probably Salmonella reflected past infections. The absence of a concomitant increase of specific IgG might possibly be explained by impaired IgM to IgG switching.
Effect of Interleukin‐7 on the In Vitro Development and Maturation of Monocyte Derived Human Dendritic Cells
Authors: Li  , Masucci  , Levitsky
Published: March 2003

We have compared the cell phenotype and functional properties of monocyte/macrophage derived dendritic cells (DCs) obtained by culture of human adherent peripheral blood mononuclear cells (PBMCs) in medium containing granulocyte macrophage colony stimulating factor (GM‐CSF) either alone (GM‐CSF‐DCs), or in combination with interleukin (IL)‐4 (IL4‐DCs) or IL‐7 (IL7‐DCs). The cell surface phenotype of GM‐CSF‐DCs and IL‐7‐DCs was characterized by a high expression of major histocompatibility complex (MHC) class I and II, CD80, CD86 and CD40. In contrast to ‘classical’ IL‐4‐DCs, these two types of DCs expressed CD14 and a CD21‐like molecule detected by two out of four CD21‐specific monoclonal antibodies (MoAb) tested. The same pattern of reactivity with CD21 specific antibodies was observed in freshly isolated adherent PBMCs but not in B lymphocytes. This reactivity was upregulated by IL‐7 in a dose dependent manner. Lipopolysaccharide (LPS) treatment induced the upregulation of CD40, CD80, CD86 and the T‐cell stimulatory capacity in IL‐4‐DCs and, to a lesser extent, in the IL‐7‐DCs whereas GM‐CSF‐DCs responded very poorly to such treatment. Our data indicate that, together with GM‐CSF, the IL‐7 drives macrophage precursors to a differentiation stage that is close to but distinct from the phenotype of IL‐4‐DCs. Comparison of DC development in the presence of IL‐7 or IL‐4 may help in dissecting signalling pathways that regulate the expression of functionally relevant DC markers.
Developmentally Regulated Expression of the Transmembrane Adaptor Protein TRIM in Fetal and Adult T Cells
Authors: Huynh T. , Würch A. , Bruyns E. , Korinek V. , Schraven B. , Eichmann K.
Published: March 2003

TRIM is a recently identified transmembrane adaptor protein which is exclusively expressed in T cells and natural killer (NK) cells. In peripheral blood T cells TRIM has been reported to coprecipitate, comodulate, and cocap with the T‐cell receptor (TCR), suggesting that it is an integral component of the TCR/CD3/ζ complex. Here we investigate the expression of TRIM mRNAs and proteins in developing thymocytes. Two splicing isoforms with open reading frames are observed, namely a full length (TRIM) and a truncated version (ΔTM‐TRIM). The latter lacks the extracellular and transmembrane domains as well as the first 10 cytoplasmic aminoacids and is significantly expressed only as mRNA in early fetal thymocytes. TRIM mRNA is detected in all mainstream thymocyte subsets in adult mice. TRIM protein, in contrast, first appears in the DN2 (CD44+ CD25+) subset of adult double negative (DN) cells. In fetal thymocyte development, TRIM mRNA is seen from dg 14.5 onwards whereas TRIM protein appears first on dg 16.5. In contrast to the adult, the TRIM protein was seen in a subset of fetal DN1 cells. In fetal and adult thymocytes, TRIM protein expression was highest in DN2, DN3 (CD44−25+) and in DP cells, compatible with a functional role at or around phases of thymic selection.
Structure and Chromosomal Localization of Chicken CD5
Authors: Koskinen R. , Salomonsen J. , Goodchild M. , Bumstead N. , Boyd Y. , Vainio O.
Published: March 2003

CD5 is a transmembrane glycoprotein on all T cells and on a subpopulation of B cells. Based on the analysis of chicken CD5‐cDNA we have previously shown that the structure of the CD5 protein is conserved between species. Here we report the isolation and chromosomal mapping of the chicken CD5 gene. The gene spans 3.4 kb and is extremely compact with a high GC‐nucleotide content. There are 10 exons and the introns are spliced out similarly to those in the human CD5 gene. Each of the three extracellular scavenger receptor cysteine‐rich (SRCR) domains is encoded as an exon of its own, as is the proline‐rich hinge region that separates the first two membrane‐distal SRCR domains. The fluorescence in situ hybridization (FISH) technique was used to map the gene to chromosome five. This is the first report describing the organization of the CD5 gene from a nonmammalian species.
CD80(B7.1) and CD86(B7.2) Do not Have Distinct Roles in Setting the Th1/Th2 Balance in Autoimmunity in Rats
Authors: MacPhee I. A. M. , Turner D. R. , Yagita H. , Oliveira D. B. G.
Published: March 2003

Some data suggest that the interaction between CD28 and CD80 (B7.1) stimulates Th1‐responses and that CD28 and CD86 (B7.2) stimulates Th2‐responses, however this is controversial. We addressed this issue by using mercuric chloride (HgCl2)‐induced autoimmunity in Brown Norway (BN) rats as a highly polarized Th2 model and experimental autoimmune encephalomyelitis (EAE) in Lewis rats as a highly polarized Th1 model. Monoclonal antibodies (MoAbs) to CD80 and CD86, given singly, had little effect in either model, however when given together they almost completely suppressed the HgCl2‐induced autoimmunity: the peak immunoglobulin (Ig)E concentration was 3.25 µg/ml in treated animals versus 2770 µg/ml in controls (P < 0.0001); caecal vasculitis was suppressed with a median vasculitis score of 0 in treated animals versus 6 in controls (P < 0.0001); and new germinal centre formation was significantly suppressed. A combination of the antibodies also markedly reduced the severity of clinical EAE; from a median aggregate clinical score of 9 to 3 (P = 0.02) and delayed the onset from a median of 12.5 days to 16 days after immunization (P = 0.006). We have demonstrated profound suppression of both Th1 and Th2‐driven autoimmunity in rats by a combination of anti‐CD80 and CD86, but have been unable to demonstrate any clear differential effects.
The Humoral Response in TCR α–/– Mice. Can γδ‐T Cells Support the Humoral Immune Response?
Authors: Lindroth K. , Troye‐Blomberg M. , Singh M. , Dieli F. , Ivanyi J. , Fernández C.
Published: March 2003

An optimal humoral response requires T‐cell help; however, it has been questioned if this help comes exclusively from αβ‐T cells or whether γδ‐T cells also contribute. We have attempted to answer this question by studying the humoral response in T‐cell receptor α‐chain knockout (α–/–) mice, which lack the αβT cell subset. Two model antigens were used to characterize the response: the thymus‐independent (TI) antigen native dextran B512 (Dx), and the thymus‐dependent (TD) antigen heat shock protein (HSP65) from Mycobacterium tuberculosis. When challenged with Dx, the α–/– mice elicited a strong antibody response and formed rudimentary germinal centres (GCs), a T‐cell dependent reaction. In contrast, the humoral response to HSP65 was poor. However, α–/– mice became primed when challenged with HSP65, because when supplemented with wild‐type thymocytes, the antigen‐primed animals were able to mount a stronger response than the nonprimed ones when challenged with HSP65. A crucial step seems to be the collaboration between γδT cells and antigen presenting cells (APCs), as splenocytes from α–/– mice were able to respond to HSP65 in an environment containing primed‐APCs. Based on these results, we propose a model for B‐cell activation in the α–/– mice.
Delayed and Reduced Adaptive Humoral Immune Responses in Children with Shigellosis Compared with in Adults
Authors: Raqib R. , Qadri F. , SarkEr P. , Mia S. M. S. , Sansonnetti P. J. , Albert M. J. , Andersson J.
Published: March 2003

We hypothesized that increased susceptibility to Shigella infection, increased severity of disease and high mortality in children compared with adults were consequences of insufficient adaptive immune responses. Antigen‐specific immune responses were studied in paediatric patients (n = 38, 2–10 years) with shigellosis and compared with those of adult patients (n = 30, 18–45 years). Peak frequencies of antigen (invasion plasmid coded antigen B, Ipa‐B; lipopolysaccharide, LPS)‐specific immunoglobulin (IgM)‐antibody secreting cells (ASC) were seen within 3–5 days after the onset of diarrhoea in children, while peak IgA‐ and IgG‐ASCs were obtained 8–10 days later in line with adults. Antigen‐specific ASC responses in children ranged between 2 and 4% of the total ASC responses, in contrast to 8–15% in adults. The kinetics of LPS‐specific IgG subclass titres was different in younger children (2.5–5 years) (IgG1 > IgG2 > IgG4 > IgG3) compared with in older children (6–8 years) (IgG2 > IgG1 >IgG3 > IgG4) and adults. Secretory IgA levels in stool peaked 8–10 days after onset in both adults and children. However, a rapid induction of stool LPS‐specific IgA, IgA1 and IgA2 occurred in adult patients within 3–5 days of onset, while in children, this was delayed by 8–10 days. Similarly, higher number of tumour necrosis factor (TNF)‐α and interferon (IFN)‐γ expressing cells in vitro were seen in adult patients in response to antigens (LPS and Ipa‐B) in the acute stage in contrast to paediatric patients. Thus, paediatric patients with shigellosis have reduced and delayed adaptive immune responses compared with adult patients.
Immune Regulation in Adjuvant Disease and Other Arthritis Models: Relevance to Pathogenesis of Chronic Arthritis
Authors: Waksman B. H.
Published: March 2003

Experimental models of arthritis and their human counterparts fall into three distinct classes: (a) responses of T cells to disseminated microbial antigens (Ags) as such; (b) responses of T cells to cartilage autoAgs; and (c) responses of T cells to major histocompatibility complex (HLA‐B27, DRB1) or other membrane components (LFA‐1) expressed on bone marrow‐derived cells. The primary immune response is driven, in naturally occurring disease, by microbial infection, e.g. with streptococci, enteric gram‐negative rods or spirochetes, or is experimentally induced with mycobacterial and other adjuvants. The response to cartilage components, such as collagen type‐II and various proteoglycans, may be driven by cross‐reactive microbial Ags, heat shock proteins (HSPs) in particular, or the adjuvant effect of intense primary joint inflammation, as in rheumatoid arthritis and the spondyloarthropathies.

Adjuvant disease appears to be purely T‐cell‐mediated, whereas both T cells and antibody play a role in collagen and many other forms of arthritis. Experimental evidence suggests a pathogenetic role for T‐cell receptor γδ T cells in some lesions. Arthritis may be regulated by microbial and tissue HSPs, when these are administered by a nonimmunizing route or as altered peptide ligands, by anti‐idiotypic responses that block the action of effector T cells, and by competing Ags. Immune regulation involving natural killer (NK), NK T and certain subsets of γδ and αβ T cells, which may affect the occurrence, localization and character of this group of diseases, presents a challenge for further investigation.
Transforming Growth Factor‐β (TGF‐β) and Tissue Transglutaminase Expression in the Small Intestine in Children with Coeliac Disease
Authors: Hansson T. , Ulfgren A.‐K. , Lindroos E. , DannÆus A. , Dahlbom I. , Klareskog L.
Published: March 2003

The production of cytokines from T cells and macrophages is of potential importance for the histological changes apparent in coeliac disease (CoD). Small intestinal biopsy specimens from children with CoD and disease control subjects were investigated for their content of cytokines and tissue transglutaminase (tTG). The transforming growth factor‐β1 (TGF‐β1) expression was increased in the lamina propria of children with villous atrophy. In contrast, TGF‐β3 was expressed at a higher level in the epithelium and the lamina propria of the disease control subjects. The tTG expression was increased in the small intestine of CoD patients as compared with that in subjects. Interleukin‐4 (IL‐4) was detected in the lamina propria of both CoD patients and controls, and some of the investigated biopsy specimens also showed IL‐4 expression in the epithelium. We conclude that children with active CoD could have an altered expression of TGF‐β and tTG in the small intestine and that a disturbed regulation of TGF‐β may be of importance in the immune pathogenesis of CoD.
TSST‐1 Induces Th1 or Th2 Differentiation in Naïve CD4+ T Cells in a Dose‐ and APC‐Dependent Manner
Authors: Brandt K. , Van Der Bosch J. , Fliegert R. , Gehring S.
Published: March 2003

Superantigens are potent activators of the immune system, causing a variety of diseases, ranging from food poisoning to septic shock. Here, we examined the effects of different toxic shock syndrome toxin 1 (TSST‐1) concentrations on the activation, proliferation and synthesis of interferon‐γ (IFN‐γ) and interleukin‐4 (IL‐4) in purified naïve human CD4+ T cells in a serum‐free in vitro system. TSST‐1 given in low doses (1–10 pg/ml) generates a pronounced T helper 2 (Th2)‐like cytokine profile, characterized by elevated IL‐4‐expressing T‐cell populations and reduced IFN‐γ‐producing populations, whereas higher doses (100 pg/ml) induce a Th1‐like profile, with increased expression of IFN‐γ and reduced expression of IL‐4. These patterns were even more pronounced by adding exogenous cytokines like IL‐12 and IL‐4 and by the type of antigen‐presenting cells (APCs). Thus, B cells induced Th2 shifts, whereas monocytes favoured Th1 induction. Moreover, IL‐12 in conditions with B cells counteracted their Th2 bias. Interestingly, in purified naïve T‐cell cultures, containing a small population of HLA‐DR+ T cells, Th1/Th2 differentiation can be induced by TSST‐1 too. There, Th‐cell polarization is strongly dependent on TSST‐1 concentration, indicating that this is a key parameter in regulating the differentiation of T cells. In conclusion, our data show that Th1/Th2 differentiation of TSST‐1‐stimulated naïve T cells is controlled by the type of APCs, and in APC‐depleted cultures, it depends on the presence of HLA‐DR+ cells and TSST‐1 concentration.
Interferon‐γ‐Secreting T Cells Localize to the Epithelium in Coeliac Disease
Authors: Olaussen R. W. , Johansen F. E. , Lundin K. E. A. , Jahnsen J. , Brandtzaeg P. , Farstad I. N.
Published: March 2003

Increased levels of interferon‐γ (IFN‐γ) transcripts have previously been found in duodenal biopsy specimens from patients with untreated coeliac disease (CD). Such samples and duodenal control mucosa were therefore studied to locate and phenotype cells spontaneously secreting IFN‐γ. Specimens were collected from consecutively recruited patients with untreated (seven), treated (four) or refractory (three) CD and from five histologically normal controls. Morphological and immunohistochemical examinations were performed, and epithelial and lamina propria cell suspensions were prepared from parallel samples. Unstimulated viable cells secreting IFN‐γ were identified and phenotyped with a new fluorescence‐activated cell sorter‐based assay, and IFN‐γ messenger RNA (mRNA) was analysed in snap‐frozen aliquots of the same suspensions. Untreated CD cases had the highest fraction of IFN‐γ+ cells in the epithelial compartment (median 2.6%, range 1.6–6.2%) and, less strikingly, in the lamina propria compartment (1.6%, range 0.3–3.6%), followed by refractory (1.4%, 1.0–1.9%; and 0.3%, 0.0–1.2%) and treated (0.8%, 0.5–0.9%; and 0.7%, 0.2–1.1%) disease and finally the controls (0.5%, 0.3–0.9%; and 0.2%, 0.1–0.7%). IFN‐γ mRNA data supported these findings. IFN‐γ+ intraepithelial lymphocytes were mostly CD3+ and CD8+, whereas many positive lamina propria cells were CD8–. We conclude that isolated T cells spontaneously secreting IFN‐γ localize preferentially in the epithelium of patients with classical and refractory CD.
Single‐Cell Analysis of Ets‐1 Transcription Factor Expression during Lymphocyte Activation and Apoptosis
Authors: Koskela K. , Lassila O.
Published: March 2003

The Ets‐1 proto‐oncogene is a prototype member of Ets family of transcription factors. It is preferentially expressed in lymphoid cells, where it is essential for the maintenance of the normal pool of resting T and B cells. We have investigated the protein expression of the Ets‐1 transcription factor during the activation and apoptosis of T and B cells by flow cytometry and confocal microscopy. Cells of the thymus, spleen and bursa expressed high levels of Ets‐1 protein, while resting peripheral blood mononuclear cells had lower Ets‐1 expression. Activation and proliferation of T cells induced the upregulation of Ets‐1. αβ‐T cells were found to upregulate Ets‐1 expression more than γδ‐T cells. Increased Ets‐1 protein expression was located predominantly in the perinuclear area. In contrast, during apoptosis, Ets‐1 expression was downregulated. Collectively, our results indicate that Ets‐1 expression can be accurately determined by flow cytometry and confocal microscopy. Ets‐1 expression level and distribution are differentially controlled in resting, activated and apoptotic lymphocytes.
Calcineurin Phosphatase Activity and Immunosuppression. A Review on the Role of Calcineurin Phosphatase Activity and the Immunosuppressive Effect of Cyclosporin A and Tacrolimus
Authors: Jørgensen K. A. , Koefoed‐Nielsen P. B. , Karamperis N.
Published: March 2003

The mode of immunosuppressive action of tacrolimus (FK506) and cyclosporin A has been elucidated. Both drugs bind to proteins in the cytoplasm to form complexes, which in turn inhibit the phosphatase activity of calcineurin, an important limiting step in the activation of T cells. The association between drug uptake (pharmacokinetics) and enzyme inhibition (pharmacodynamics) is under current investigation. Great variations in the correlation between blood drug levels and enzyme inhibition could indicate that monitoring calcineurin phosphatase activity for treatment might be superior to monitoring blood drug levels.
Abiogenic silica layers within a fluvio‐lacustrine succession, Bolzano Volcanic Complex, northern Italy: a Permian analogue for Magadi‐type cherts?
Authors: KRAINER KARL , SPÖTL CHRISTOPH
Published: March 2003

Thin layers of chert occur within a fluvio‐lacustrine succession sandwiched between acidic volcanic rocks of the Lower Permian Bolzano Volcanic Complex in northern Italy. These cherts are interpreted as analogues to Magadi‐type abiogenic chert known from modern volcanic lake settings. Soft‐sediment deformation features, shrinkage cracks, and well‐preserved palynomorphs document very early diagenetic silica precipitation, volume loss by dehydration, and consolidation prior to mechanical compaction of the sediment. Transformation to quartz and concomitant (re)crystallization resulted in a variety of silica textures, dominated by microflamboyant quartz. The oxygen isotopic composition of chert samples ranges from +25·4 to +29·0‰ and is negatively correlated with crystal size and ordering.
Palaeogeographic and burial controls on anhydrite genesis: the Badenian basin in the Carpathian Foredeep (southern Poland, western Ukraine)
Authors: KASPRZYK ALICJA , ORTÍ FEDERICO
Published: March 2003

The Badenian (Middle Miocene) Ca‐sulphate deposits of the fore‐Carpathian basin – including the shelf and adjacent salt depocentre – have undergone varying degrees of diagenetic change: they are preserved mainly as primary gypsum in the peripheral part of the platform, whereas toward the centre of the basin, where great subsidence occurred during the Miocene, they have been totally transformed into anhydrite.

The facies variation and sequence of Badenian anhydrites reflect different genetic patterns of two members of the Ca‐sulphate formation. In the lower member (restricted to the platform), anhydrite formed mainly by synsedimentary anhydritization (vianodule formation), whereas in the upper member (distributed throughout the platform and depocentre) the various gypsum/anhydrite lithofacies display a continuum of distinctive anhydrite type‐fabrics. These fabrics are based on petrographic features and show from the centre to the margin: (1) syndepositional, interstitial growth of displacive anhydrite; (2) early diagenetic, displacive to replacive (by replacement of former gypsum) anhydrite formation near the depositional surface; (3) early diagenetic, displacive to replacive anhydrite formation during shallow burial; and (4) late‐diagenetic (and only partial) replacement of gypsum at deeper burial. The cross‐shelf lateral relations of anhydrite lithofacies and fabrics suggest that the diagenesis developed as a diachronous process.

These fabrics of the upper member reflect both palaeogeographic (linked to different parts of the basin) and burial controls. Anhydrite growth started very early in the basin centre, presumably related to high‐salinity pore fluids; anhydritization prograded updip toward the shelf (landward in a generalized cross‐section through the basin). The intensity of gypsum replacement by anhydrite was progressively attenuated landward by a decrease in the salinity of the pore fluids. In each part of the basin, the anhydrite fabric was also controlled by the texture and degree of lithification of the fine‐grained primary gypsum lithofacies. Recrystallization of these anhydrite fabrics during late diagenesis, linked to deeper burial conditions, is insignificant, allowing reconstruction of the original anhydritization pattern.
Depositional environment of a Kimmeridgian carbonate ‘black band’ (Akkuyu Formation, south‐western Turkey)
Authors: Baudin François , Tribovillard Nicolas , Laggoun‐Défarge Fatima , Lichtfouse Eric , Monod Olivier , Gardin Silvia
Published: March 2003

The Upper Jurassic Akkuyu Formation of south‐western Turkey consists of pale‐coloured carbonate facies, but includes a peculiar ‘black band’ at its base. In order to characterize the depositional environment of this level, a sedimentological, organic and inorganic geochemical study was performed on 30 samples. Three units are distinguished. Unit 1 consists of black marlstones, very rich in organic carbon (22–30%) with HI (hydrogen index) values around 600. The organic matter is an amorphous homogeneous material even at nanoscopic scale. This unit is also characterized by a very high concentration of V ( >1000 p.p.m.) and a δ13Corg value around −26·5‰. Unit 2 shows thin‐bedded black limestones with chert layers. Its organic content varies from 2% to 6%. As in unit 1, the HI values are uniformly high (600), and gas chromatography shows a high quantity of hopanes. The V concentration is also high (≈400 p.p.m.). The unit has a high Sr/Ca ratio, an organic carbon isotopic ratio close to −28·7‰ and diffuse, nanoscopically amorphous organic material that is closely associated with pyrite. Unit 3 corresponds to the white limestones overlying the ‘black band’. This calcitic facies is almost devoid of organic carbon (<0·1%). The δ13Corg values are similar to those of unit 1 (−25·5‰ to −26‰). Deposition occurred in a basinal environment surrounded by a carbonate platform. Primary productivity was high but not exceptional; terrestrial organic inputs were scarce. Bottom waters were probably euxinic during the deposition of unit 1. The presence of both hopane‐rich and sulphur‐rich nanoscopically amorphous organic matter may be the result of strong sulphate‐reducing bacterial activity. Coupled with low amounts of iron, this led to intense vulcanization of the organic matter and thus good preservation. With the onset of unit 2 deposition, environmental conditions became less extreme, perhaps because of cooler water temperatures. Finally, the depositional conditions became oxic, leading to the accumulation of pale‐coloured organic‐poor limestones of unit 3.
Classification of paraglacial barrier systems: coastal New England, USA
Authors: Fitzgerald Duncan M. , Van Heteren Sytze
Published: March 2003

The New England coast harbours a wide variety of barrier forms, which we organize into six barrier‐coastline types. The barriers develop in response to the relative importance of several spatially and temporally variable parameters, particularly antecedent topography and geology, sediment abundance and size, exposure to wave and tidal energy and sea‐level history. The six coastline types can also be identified in other paraglacial regions. Existing barrier‐coastline classification schemes do not allow consistent subdivision of paraglacial barrier coasts. This paper presents a new scheme that is applicable to paraglacial and non‐paraglacial barrier coasts alike. Aside from hydrodynamic regime, which forms the basis of the barrier classification most commonly used to date, it includes a compartmentalization factor. Sediment‐starved ‘isolated’ (‘type 1’) barrier coastlines are characterized by short, widely spaced barriers. Small, localized updrift and offshore sources have provided sediment for short barriers along ‘clustered headland‐separated’ (‘type 2’) barrier coastlines. Various amounts of sediment from larger updrift and offshore glaciofluvial deposits or directly from rivers have formed the longer barriers along ‘wave‐dominated mainland‐segmented’ (‘type 3a’), ‘mixed‐energy mainland‐segmented’ (‘type 3b’), ‘wave‐dominated inlet‐segmented’ (‘type 4a’) and ‘mixed‐energy inlet‐segmented’ (‘type 4b’) barrier coastlines. Geomorphic form, grain size and stratigraphy can be used to characterize individual barriers along barrier coastlines. Most paraglacial barriers form as spits, but many are transformed subsequently. Welded barriers are common along ‘type 1’ and ‘type 2’ coasts. Baymouth barriers are characteristic of ‘type 3’ coasts, and barrier islands occur exclusively along ‘type 4’ coasts. The coarsest grained barriers are located along ‘type 1’ and ‘type 2’ coasts. Progradational barrier sections are concentrated along ‘type 3’ and ‘type 4’ coasts with abundant sediment supply, but are also present along ‘type 2’ coasts. Temporary increases in sediment supply, common in paraglacial regions, result in transitions between retrogradational and progradational barrier behaviour, which may be recognized on shore‐perpendicular stratigraphic cross‐sections.