bluuebunny/crossref_metadata_2025 huggingface dataset:
Pityrosporum orbiculare‐Reactive T‐Cell Lines in Atopic Dermatitis Patients and Healthy Individuals
Authors: Tengvall Linder  , Johansson  , Bengtsson  , Holm  , Härfast  , Scheynius
Published: March 2003

The yeast Pityrosporum orbiculare is one of the factors that may contribute to atopic dermatitis (AD). In the present study we compared the T‐cell response to P. orbiculare in 12 AD patients with specific immunoglobulin (Ig)E antibodies (Ab) in serum against P. orbiculare with that of six non‐atopic healthy controls. Freshly isolated peripheral blood mononuclear cells (PBMC) were cultured for 3 days in the presence of P. orbiculare extract. The proliferative response as measured by [3H]‐thymidine incorporation was significantly higher in the AD patients than in the healthy controls (P < 0.05). Furthermore, significantly higher levels of interleukin (IL)‐5 (P < 0.05), as analyzed by ELISA, were produced by PBMC from the AD patients compared to the healthy controls. Pityrosporum orbiculare‐reactive T‐cell lines (TCL) established by P. orbiculare stimulation of PBMC for 11 days produced significantly higher levels of IL‐4 and IL‐5 after stimulation with anti‐CD3 Ab and showed a higher IL‐4/interferon (IFN)‐γ ratio (P < 0.05) in the AD patients compared to the healthy controls. The higher proliferative PBMC response to P. orbiculare and the Th2‐like cytokine production by P. orbiculare‐stimulated TCL from AD patients indicate that P. orbiculare may play a role in maintaining skin inflammation in AD.
Bronchus‐Associated Lymphoid Tissue (BALT) and Larynx‐Associated Lymphoid Tissue (LALT) are Found at Different Frequencies in Children, Adolescents and Adults
Authors: Hiller  , Tschernig  , Kleemann  , Pabst
Published: March 2003

The lung in 98 and the larynx in 51 consecutive autopsies (age: 17th gestational week to 99 years) were studied for the presence of organized lymphoid tissue in the epiglottis and in the wall of larger bronchi. Bronchus‐associated lymphoid tissue (BALT) was seen in about 40% of patients younger than 20 years of age but in older patients only in exceptional cases. In the wall of the epiglottis, however, larynx‐associated lymphoid tissue (LALT) was found at a frequency of ≈80% in patients younger than 20 years and in 56% of the patients older than 20 years. The clinical relevance of LALT as a physiological entry site for antigens or for vaccination protocols using aerosols needs to be studied in further experiments.
Structural, Molecular and Immunological Properties of Linear B‐Cell Epitopes of Ro60KD Autoantigen
Authors: Routsias  , Sakarellos‐Daitsiotis  , Tsikaris  , Sakarellos  , Moutsopoulos  , Tzioufas
Published: March 2003

Antibodies to Ro60KD protein are found with high frequency in sera from patients with systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (pSS). Two major epitopes of the Ro60KD antigen, the TKYKQRNGWSHKDLLRSHLKP (169–190) and the ELYKEKALSVETEKLLKYLEAV (211–232), were synthesized and their antigenic and structural properties were studied. Using a large panel of SLE and pSS patients' sera, it was found that the anti‐Ro60KD reactivity of both Ro60KD epitopes is rather limited (≈45%), although they retain their original disease specificity. The epitope p.169–190 possessed sequence similarity with the peptide RPDAEYWNSQKDLLEQKRGR, shared in the β‐chain of different HLA‐DR molecules, among them the HLA‐DR3 (which is associated with anti‐Ro/Sjögren's syndrome A (SSA) response in patients with SLE). The antigenicity of the HLA‐DR3 RPDAEYWNSQKDLLEQKRGR peptide was found to be similar to the 169–190 homologous Ro60KD epitope, recognized mainly by SLE sera. Structural studies showed that the 211–232 Ro60KD epitope exhibits pronounced helical characteristics, while the 169–190 epitope and the HLA‐DR3 homologous peptide possess a somewhat lower percentage of α‐helix. A β‐folded structure was identified in the latter two peptides. Although the diagnostic value of the reported Ro60KD epitopes seems to be rather limited, correlations with other ribonucleoprotein epitopes (La/Sjögren's syndrome B, Ro52KD) may prove complementary to each other and valuable in clinical use. The ordered structure of the HLA‐DR3 homologous peptide, exposed to the autoantibody binding, may offer an initiative in further investigation of the role of the HLA haplotypes, associated with the anti‐Ro/SSA response, in the autoimmune stimulus.
Phenotype of Rat Monocytes During Acute Kidney Allograft Rejection: Increased Expression of NKR‐P1 and Reduction of CD43
Authors: Scriba  , Grau  , Steiniger
Published: March 2003

Monocytes and macrophages mediate cytotoxicity after appropriate activation and thus represent effectors secondary to T lymphocytes and natural killer (NK) cells. However, very little is known about the role of activated monocytes in organ allograft rejection. In this study, isogeneic (LEW to LEW) and fully allogeneic (DA to LEW) rat kidneys were grafted to bilaterally nephrectomized recipients. Four days after transplantation a comprehensive sample of leucocytes was recovered by perfusion of the recipients' vasculature with phosphate‐buffered saline containing EDTA (PBS/EDTA). Monocytes were enriched by density gradient centrifugation and their physical parameters and immunophenotype were investigated by flow cytometry in comparison with untreated, specified pathogen‐free (SPF) LEW rats. Isotransplantation and allotransplantation of kidneys dramatically increased the absolute number of intravascular monocytes in the recipient. Analysis of NKR‐P1 (CD161), CD4, CD62L, CD43, CD11a, CD18 and MHC class II expression identified at least two monocyte populations in all experimental groups. In graft recipients it was evident that activated monocytes were able to express and upregulate NKR‐P1 and CD8, which have not been detected in these cells to date. If activated monocytes utilize NKR‐P1 and CD8, by analogy to NK cells and lymphocytes these cells may be endowed with additional pathways to upregulate cytolytic functions and effect allograft damage.
Blockade of B7‐2, Not B7‐1, Inhibits Purified Protein Derivative‐Primed T‐Lymphocyte Responses But Fails to Influence the Proportion of Th1 Versus Th2 Subsets
Authors: Shortt  , Hart  , Watson  , Baird
Published: March 2003

The ability to select for a cell‐mediated response rather than antibody production following infection with intracellular mycobacteria, would be an advantage in preventing the occurrence of disease. Recent work suggests that the two members of the B7 family of costimulatory molecules, B7‐1 and B7‐2, may differentially influence the nature of primary immune responses but little is known of their role in this capacity in secondary responses. We have used an in vitro model to investigate whether blocking B7‐1 and B7‐2 affects changes in the cytokine profiles of Th lymphocytes previously primed to purified protein derivative (PPD) from Mycobacterium bovis. In C57BL/6 and BALB/c mice we found that the proliferative responses of a component of recently activated T lymphocytes, and those returning to the resting state, were inhibited by B7‐2 blockade. B7‐1 blockade had no distinguishable effect. However, in cultures containing anti‐B7‐2 antibody, the production of both interferon‐γ (IFN‐γ) and interleukin‐4 (IL‐4), indicative of cell‐mediated and antibody responses, respectively, were reduced. This suggests that intervention in a recall response to mycobacterial antigen by blocking B7‐1 or B7‐2 molecules, is unlikely to alter the nature of the immune response.
Contribution of Plasma‐Derived Molecules to Mucosal Immune Defence, Disease and Repair in the Airways
Authors: Persson  , Erjefält  , Greiff  , Erjefält  , Korsgren  , Linden  , Sundler  , Andersson  , Svensson
Published: March 2003

This review discusses recent observations, in health and disease, on the release and distribution of plasma‐derived molecules in the airway mucosa. Briefly, the new data on airway mucosal exudation mechanisms suggest that the protein systems of plasma contribute significantly to the mucosal biology, not only in injured airways but also in such mildly inflamed airways that lack oedema and exhibit no sign of epithelial derangement. Plasma as a source of pluripotent growth factor, adhesive, leucocyte‐activating, etc., molecules may deserve a prominent position in schemes that claim to illustrate immunological and inflammatory mechanisms of the airway mucosa in vivo.
Activation of T Cells from the Intestinal Lamina Propria of the Pig
Authors: Bailey  , Plunkett  , Clarke  , Sturgess  , Haverson  , Stokes
Published: March 2003

This study found CD4+ T cells present in leucocyte populations isolated from the lamina propria of the pig to be almost exclusively CD45RC−, consistent with their being highly differentiated by exposure to antigen. Following activation in vitro these cells up‐regulated expression of IL‐2R with similar kinetics to splenic CD4+ cells. However, while splenic cells progressively secreted IL‐2 into cultures during the first 24 h, IL‐2 was not detected in supernatants of lamina propria cells after 8 h. Reverse‐transcriptase polymerase chain reaction (RT‐PCR) confirmed that this reflected a transcriptional difference: IL‐2 transcripts were detected in cultures of splenic and lamina propria cells in the first few hours after activation but persisted only in splenic cells. In contrast, IL‐4 transcripts were strongly expressed by activated lamina propria cells. Cell‐cycle analysis demonstrated that fewer lamina propria CD4+ cells progressed into S‐phase than did splenic CD4+ cells (26.0 ± 11.1% and 45.0 ± 11.3% respectively, P = 0.011). Our results suggest that CD4+ T cells in these populations are differentiated effector cells whose potential for expansion may be dependent upon local factors. Such cells may be targets for immunoregulation by their local microenvironment.
Mannan‐Binding Lectin Deficiency is Associated with Unexplained Recurrent Miscarriage
Authors: CHRISTIANSEN  , KILPATRICK  , SOUTER  , VARMING  , THIEL  , JENSENIUS
Published: March 2003

Mannan‐binding lectin (MBL) is a plasma protein which, upon binding to microbial carbohydrate structures, elicits activation of the complement system. The level of MBL is genetically determined. It has been reported that the frequency of low plasma levels of MBL is increased in patients with unexplained recurrent miscarriages (RM). In the present study plasma MBL levels were determined in 146 Danish women with RM and 41 of their husbands together with 49 Scottish RM women and 41 of their husbands. In both countries MBL levels were also investigated in a total of 444 controls. Based on the control data, a cut‐off MBL level < 50 ng/ml was selected to define MBL deficiency. The typical odds ratio for MBL deficiency among female patients in the two populations was 1.68 (95% confidence limits 1.01–2.80, P < 0.05) whereas it was 1.57 (95% confidence limits 0.72–3.42, not significant) for the male partners of the patients. There was a significant correlation between the frequency of MBL deficiency in RM women and the number of previous miscarriages (P < 0.01), whereas no such correlation was found in the husbands. The results indicate that maternal MBL deficiency is associated with RM. Maternal MBL deficiency might impair the immune defence against micro‐organisms at the feto‐maternal interface.
Bacillus thuringiensis Cry1Ac Protoxin is a Potent Systemic and Mucosal Adjuvant
Authors: VÁZQUEZ  , MORENO‐FIERROS  , NERI‐BAZÁN  , DE LA RIVA  , LÓPEZ‐REVILLA
Published: March 2003

Recently we demonstrated that recombinant Cry1Ac protoxin from Bacillus thuringiensis is a potent systemic and mucosal immunogen. In this study we compared the adjuvant effects of Cry1Ac and cholera toxin (CT) for the hepatitis B surface antigen (HBsAg) and bovine serum albumin (BSA). The antibody responses of intestinal secretions and serum were determined by ELISA in Balb/c mice immunized through the intragastric (IG) or intraperitoneal (IP) routes. When HBsAg was administered via IG, the anti‐HBsAg intestinal response was not enhanced by either Cry1Ac or CT, whereas via IP Cry1Ac increased the anti‐HBsAg intestinal immunoglobulin (Ig)G response and CT increased the intestinal IgA and IgM responses. Serum anti‐BSA antibodies increased when BSA was co‐administered with CT or Cry1Ac by both routes. Cholera toxin and Cry1Ac co‐administered via IP increased the IgG anti‐BSA response in fluid of the large intestine and CT also increased the IgA and IgM responses slightly. When co‐administered via IP, CT and Cry1Ac did not affect the IgG anti‐BSA response of the small intestine significantly. We conclude that Cry1Ac is a mucosal and systemic adjuvant as potent as CT which enhances mostly serum and intestinal IgG antibody responses, especially at the large intestine, and its effects depend on the route and antigen used. These features make Cry1Ac of potential use as carrier and/or adjuvant in mucosal and parenteral vaccines.
Effects of Cytokines, Butyrate and Dexamethasone on Serum Amyloid A and Apolipoprotein A‐I Synthesis in Human HUH‐7 Hepatoma Cells
Authors: Malle  , Leonhard  , Knipping  , Sattler
Published: March 2003

Serum amyloid A (SAA) and apolipoprotein A‐I (apo A‐I) are secreted by the liver. As concentrations of both apolipoproteins are inversely related under normal and acute‐phase conditions, human HUH‐7 hepatoma cells were stimulated with interleukin (IL)‐1α (100 and 200 U), IL‐6 (50 and 100 U), butyrate (2 m m) and dexamethasone (2 × 10−7 m and 1 × 10−6 m), alone or in combination. Changes in SAA and apo A‐I synthesis were monitored after metabolic labelling of the cells with [35S]‐methionine. Intracellular and secreted SAA and apo A‐I were immunoprecipitated, separated by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), and the radioactivity in the corresponding bands was counted. Intracellular apolipoprotein levels were increased by all stimuli, either alone or in combination, between 2.7‐ and 5.5‐fold (SAA) and between 2.8‐ and 4.1‐fold (apo A‐I), respectively. In a similar manner, apolipoprotein levels secreted by HUH‐7 cells were increased between 3.1‐ and 4.3‐fold (SAA) and between 1.9‐ and 3.3‐fold (apo A‐I). Co‐administration of cytokines, butyrate and/or dexamethasone had no pronounced synergistic effect on intracellular biosynthesis and secretion of SAA and apo A‐I. The results from the present study suggest that apo A‐I must not necessarily be considered as a negative acute‐phase reactant.
Transforming Growth Factor‐β1 Suppresses Interleukin‐15‐Mediated Interferon‐γ Production in Human T Lymphocytes
Authors: Bönig  , Banning  , Hannen  , Kim  , Verheyen  , Mauz‐Körholz  , Körholz
Published: March 2003

One of the most remarkable means by which tumour cells manage to evade recognition and elimination by the immune system is the release of immunosuppressive mediators, such as interleukin (IL)‐10 or transforming growth factor‐β (TGF‐β). For antitumour immunotherapies to reach their full potential, cytokine cocktails will have to be custom‐tailored to the tumour's individual cytokine microenvironment. One of the components of such a cytokine cocktail may be interleukin (IL)‐15, which has demonstrated an excellent stimulatory potential of antitumour immunity. In an in vitro model, we have previously been able to show that the negative effects of IL‐10 on IL‐15‐mediated cytotoxic T‐cell activation can be outweighed by the addition of interleukin (IL)‐12. The mechanism by which TGF‐β may influence the effect of IL‐15 remains poorly understood, however. We have therefore taken our T‐cell model further and have studied the effect of TGF‐β on IL‐15‐mediated interferon‐γ (IFN‐γ) production. In activated, IL‐15‐stimulated peripheral blood T lymphocytes, TGF‐β suppressed IFN‐γ mRNA and protein levels by ≈ 75%. This effect was likewise observed on both CD4+ and CD8+ T cells and, in contrast to the effect of IL‐10 in this system, could not be neutralized by the addition of IL‐12. Thus, immunotherapy for TGF‐β‐producing tumours may benefit from the addition of TGF‐neutralizing activity rather than IL‐12.
Self and Nonself Stimulatory Molecules Induce Preferential Expansion of CD5+ B Cells or Activated T Cells of Chagasic Patients, Respectively
Authors: Dutra  , Colley  , Pinto‐Dias  , Gazzinelli  , Brener  , Pereira  , Coffman  , Correa‐Oliveira  , Carvalho‐Parra
Published: March 2003

It has previously been demonstrated that Trypanosoma cruzi‐derived antigens (TRP) and human parasite‐specific antibodies (Id) stimulate proliferation of cells from
chagasic patients. More recently, we have shown that activated T cells and CD5+ B cells are present in elevated levels in the peripheral blood of
chagasic patients. Upon in vitro exposure to these two different types of stimulatory molecules (TRP, Id), we now show that each of these elevated populations respond differentially to TRP or Id. We found that stimulation with TRP led to preferential expansion of activated T cells, while Id preferentially stimulated CD5+ B cells and CD8+ T cells. Moreover, this expansion of CD5+ B cells by Id was even more pronounced in cultures of cells from
chagasic patients with the severe, cardiac form of the disease, as compared to indeterminate patients. CD8+ T cells comprise approximately 50% of the total T cells in cultures stimulated by Id while in TRP‐stimulated cultures their frequency is proportionally lower. Since parasite antigens and antiparasite antibodies are always present in the host during the chronic phase of the disease, they may also be involved with differential activation mechanisms of these cell populations in vivo.
Toremifene Increases the Expression of Intercellular Adhesion Molecule‐1 (ICAM‐1) on MCF‐7 Breast Cancer Cells and Jurkat Cells
Authors: Komi  , Lassila
Published: March 2003

The present study was conducted to reveal the effect of the nonsteroidal anti‐oestrogen toremifene on the expression of cell‐surface molecules involved in the immunogenicity of tumours or the sensitivity of tumour cells to apoptotic cell death. We studied the effect of toremifene on the expression of HLA‐DR, ICAM‐1, costimulatory molecules CD80 and CD86, and the tumour necrosis factor receptor (TNF‐R) family molecules CD27, CD30, CD40, TNF‐R1, TNF‐R2 and Fas (CD95) on MCF‐7 breast cancer and Jurkat T cells. In addition, the effect of toremifene on Fas‐mediated apoptosis was studied. Toremifene did not affect Fas expression or Fas‐mediated apoptosis in Fas‐resistant MCF‐7 or Fas‐sensitive Jurkat cells, but was found to increase the expression of ICAM‐1 in both cell lines. In addition, toremifene increased the expression of CD40 and CD80 on MCF‐7 cells. The expression of ICAM‐1 in tumours plays an important role in the interaction of tumour cells and effector cells of the immune system. Therefore, we suggest that toremifene may modulate the immunogenicity of tumour cells by increasing the expression of ICAM‐1.
Immunotherapy of Crohn's Disease
Authors: Van Deventer
Published: March 2003

CD4+ T‐lymphocytes have a central role in the pathogenesis of Crohn's disease. The activation and proliferation of T‐lymphocytes following stimulation by antigen‐presenting cells is controlled by regulatory cytokines (i.e. IL‐10) and by induction of programmed cell death. Tissue damage as a result of T‐lymphocyte‐mediated inflammation is mediated by pro‐inflammatory cytokines, including TNF‐α. Novel immunodulatory strategies in Crohn's disease are based on these principles, and it has been demonstrated that neutralization of TNF‐α by administration monoclonal antibodies as well as administration of recombinant human IL‐10 have therapeutic activity in Crohn's disease. The current status of these new therapies as well as future developments are discussed.
A Novel Activation Induced Lymphocyte Surface Antigen, 90.12, Is Also Expressed on Apoptotic Cells
Authors: Clark  , Monser  , Stein  , Shapiro
Published: March 2003

We describe a monoclonal antibody, mAb 90.12, which recognizes a novel activation induced lymphocyte surface antigen. Flow cytometric analysis of normal tissues shows the antigen to be expressed on higher percentages of B lymphocytes in the bone marrow than in the spleen and the lymph node. Similarly, the 90.12 antigen is expressed on higher percentages of thymocytes than peripheral T cells. MAb 90.12 immunoprecipitates three proteins with a molecular weight of 12–18 kDa which are not linked to the membrane by phosphotidylinositol. Expression of the 90.12 antigen is increased on activated B cells and the extent of upregulation varies with the stimulus. Lipopolysaccharide (LPS) stimulation results in expression on most B cells, while expression is upregulated on only a subset of B cells stimulated with anti‐immunoglobulin M (IgM), interleukin(IL)4 and IL5. Finally, we show that 90.12 antigen expression is also increased on apoptotic cells.
Enhanced Sialyltransferase Activity in B Lymphocytes from Patients with Primary Sjögren's Syndrome
Authors: Basset  , Durand  , Mimassi  , Pennec  , Youinou  , Dueymes
Published: March 2003

Despite the indisputable role of immunoglobulin (Ig)A in the pathogenesis of primary Sjögren syndrome (pSS), the causative abnormality remains largely unknown. As an extension of our report that IgA is oversialylated in this disease, the thrust of the present study was to measure the sialyltransferase (ST) activity in B lymphocytes. ST containing lysates of B cells from 17 pSS patients and 10 controls, were obtained using a combination of detergents, and incubated with affinity purified IgA that had been previously desialylated. The deposition of cytidine 5′ monophosphate sialic acid (SA) by ST from B cells onto IgA was detected by two ELISA based upon the use of biotinylated lectins (Sambucus nigra agglutinin which is specific for α2–6 SA and Maackia amurensis which is specific for α2–3 SA). In parallel, the amount of SA on IgA from ten of the 17 patients and eight of the 10 controls was assayed using the same method. An excess of α2–3 and α2–6 SA on IgA was found in those patients with excessive activity of α2–3 and α2–6 ST. Thus, IgA hypersialylation in pSS patients may result from undue activity of ST.
Immature B Cells in Bone Marrow Express Fas/FasL
Authors: Nilsson  , Ingvarsson  , Borrebaeck
Published: March 2003

Negative selection is a process by which autoreactive lymphocytes are eliminated from the developing antigen receptor repertoire. The mechanisms regulating negative selection of immature B lymphocytes in the bone marrow are poorly elucidated. Human bone marrow cells were examined in order to investigate the presence of the members of the Fas (APO‐1/CD95) system. Here we demonstrate the expression of Fas in immature B lymphocytes (CD10/CD19+/CD40+/sIg+), and the presence of Fas natural ligand (FasL) in CD19+ bone marrow cells. The observed expression of apoptosis‐related molecules might indicate how negative selection of autoreactive B cells can occur in human bone marrow.
The Role of Interleukin‐4 in the Regulation of Sequential Isotype Switch from Immunoglobulin G1 to Immunoglobulin E Antibody Production
Authors: Sudowe  , Arps  , Vogel  , Kölsch
Published: March 2003

The immunoglobulin (Ig)E immune response against protein antigens is profoundly influenced by the antigen dose used for immunization. Whereas immunization of CBA/J mice with low antigen doses results in the production of large amounts of IgE antibody, priming with high antigen doses leads to only marginal IgE antibody production in animals. However, in vitro restimulation of spleen cells from mice primed with high antigen doses leads to considerable activation of IgE‐producing B cells, which suggests that B cells primed for IgE antibody production do exist among spleen cells. We investigated the modalities of activation of these memory B cells. The data presented here reveal that the anamnestic IgE immune response in vitro is strictly dependent on the presence of IgG1‐expressing B cells, which differentiate after a sequential isotype switch into IgE‐producing plasma cells with the help of primed CD4+ T cells. The induction of IgE‐producing plasma cells requires a cognate interaction between B cells and CD4+ T cells. Interleukin (IL)‐4 seems not to be involved in this process, since IgE production in vitro is resistant to suppression by anti‐IL‐4 monoclonal antibody. Finally, we show that IgG1‐expressing B cells represent a relevant memory cell population in vivo also, but in contrast to the in vitro situation the final differentiation into IgE‐producing plasma cells is dependent on IL‐4.
Ex Vivo Interferon‐γ Response to Human Immunodefiency Virus‐1 Derived Peptides in Human Immunodeficiency Virus‐1 Infected Patients
Authors: Hober  , Benyoucef  , Chehadeh  , De Groote  , De La Tribonnière  , Mouton  , Wattré
Published: March 2003

The pattern of human immunodeficiency virus (HIV)‐1 antigen‐activated production of interferon (IFN)‐γ by immunocompetent cells of HIV‐1 infected patients has been studied using a simplified assay combining a small volume (25 μl) of whole blood stimulation with various HIV‐1 antigens, and cytokine measurement in the same wells of microtitre plates (enzyme‐linked immunotrapping assay, ELITA). The levels of IFN‐γ were higher using this assay than in the supernatant from stimulated whole blood cultures, therefore ELITA was used in the rest of the study. Specific immune responses to HIV‐1 proteins (gp120, p24) and synthetic peptides derived from these proteins and from gp41 were detected in patients, but not in healthy controls. Decreased levels of IFN‐γ were observed in CDC class B (n = 5) and C (n = 4), compared with CDC class A (n = 5), following HIV‐1 antigen‐specific challenge. The positive response of cells from different patients to overlapping peptides of p25 (amino acids 329–344 and 335–351) was suggestive of a new epitope of HIV‐1 gag recognized by T cells in the overlap region. In conclusion, the difference in in vitro antigen‐specific T‐cell responses of HIV‐1‐infected patients was shown using the ELITA method. Our results raise the possibility of using this method in screening specific antigens in HIV‐1 infection.
The Phosphatase Domains of CD45 are Required for Ligand Induced T‐Cell Receptor Downregulation
Authors: Kastrup  , Lauritsen  , Menné  , Dietrich  , Geisler
Published: March 2003

Down‐regulation of the T‐cell receptor (TCR) plays an important role in modulating T‐cell responses, both during T‐cell development and in mature T cells. At least two distinct pathways exist for TCR down‐regulation: down‐regulation following TCR ligation; and down‐regulation following activation of protein kinase C (PKC). Ligand‐induced TCR down‐regulation is dependent on protein tyrosine kinase (PTK) activity and seems to be closely related to T‐cell activation. In addition, previous studies have indicated that ligand‐induced TCR down‐regulation is dependent on the expression of CD45, a transmembrane protein tyrosine phosphatase. The role of the different domains of CD45 in TCR down‐regulation was investigated in this study. We found that the phosphatase domains of CD45 are required for efficient ligand‐induced TCR down‐regulation. In contrast, the extracellular domain of CD45 is dispensable for ligand‐mediated TCR down‐regulation. Finally, PKC‐mediated TCR down‐regulation was found to be independent of both the extra‐and intracellular domains of CD45.
Non‐Major Histocompatibility Complex Dependent Variations in Lymphocyte Activity Between Inbred Mouse Strains Susceptible to Various Autoimmune Diseases
Authors: Johansson  , Vestberg  , Holmdahl
Published: March 2003

Transgenic techniques in inbred mouse strains are powerful tools to investigate the specific roles of genes in biological pathways and disease models. However, there is increasing concern over the influence of a variable genetic background in such experiments. To date there have been few investigations of the immunological differences between inbred mouse strains used in models of autoimmune diseases. Here we phenotyped lymph node cells and T‐cell cytokine production in B10.Q (H2q), B10.RIII (H2r), C3H.Q (H2q), C3H.NB (H2p), NOD (H2g7), RIII/SJ (H2r) and DBA/1J (H2q) mice. We found several significant differences. The C3H strains and RIII/SJ lymph node cells had a high ratio of T cells/B cells (> 2 : 1) and a high ratio of CD4/CD8 positive cells (> 3 : 1), these strains are therefore denoted high T cell ratio (HiTR) strains. B10 strains and DBA/1, however, displayed an expansion of γδT cells after mitogen activation. T cells derived from C3H and DBA/1J strains produced more interleukin (IL)‐4 than did T cells from B10 and NOD strains. DBA/1J and B10.Q showed a 10‐fold increase in interferon (IFN)‐γ producing cells in the CD4+ T‐cell population. Variation in the number of IL‐2 and IFN‐γ producing T cells between the B10 major histocompatibility complex (MHC) congenic strains was the only difference possibly controlled by the MHC region. We conclude that non‐MHC genes influence the numbers of T cells and B cells in lymph nodes, as well as IFN‐γ, IL‐4 and IL‐10 production by T cells.
Reduced Formation of Phosphatidic Acid upon B‐Cell Receptor Triggering of Mouse B‐Lymphocytes Lacking Bruton's Tyrosine Kinase
Authors: Forssell  , Nilsson  , Sideras
Published: March 2003

Btk deficient (BtkM) mouse B‐lymphocytes do not proliferate when stimulated with anti‐immunoglobulin (anti‐Ig) antibodies. In order to characterize the molecular basis of this unresponsiveness we have compared early signal transduction pathways triggered by ligating the B cell antigen receptor (BCR) of purified resting B cells from normal C57BL/6 (wild‐type) and BtkM mice on C57BL/6 background. BCR‐induced signalling events that occur during the first few minutes of activation, such as bulk tyrosine phosphorylations, mitogen‐activated protein kinase (MAPK) activation, PI3‐kinase dependent PKB/Akt kinase phosphorylation/activation and PLCγ2 tyrosine phosphorylation are comparable in wild type and BtkM B cells. However, the initial extracellular calcium influx is reduced and the BCR‐induced accumulation of phosphatidic acid (PA) display a more transient profile in the BtkM cells. BCR ligation did not induce detectable phosphatidyl‐choline PLD activity, suggesting that the reduced PA is owing to a reduction in the phospho‐inositide hydrolysis. These findings further support the notion that the proliferative defect of Btk deficient mouse B cells in response to anti‐immunoglobulin stimulation stems from a failure to sustain phospholipase‐dependent signalling.
Activation of Murine Peritoneal Macrophages by Streptococcus pneumoniae Type II Capsular Polysaccharide: Involvement of CD14‐Dependent Pathway
Authors: Um  , Son  , Kim  , Moon  , Rhee  , Pyo
Published: March 2003

In this study we examined the ability of capsular polysaccharide type 2 (PS) from Streptococcus pnemoniae to induce secretory and cellular responses in peritoneal macrophages. Tumour cytotoxicity induced by preincubation with PS was demonstrated to be concentration‐dependent. PS‐induced tumouricidal activity was partially abrogated by anti‐tumour necrosis factor (TNF)‐α and inhibitor of nitric oxide, whereas anti‐interferon (IFN)‐α/β antibody and the scavengers of reactive oxygen intermediates had no effect. In addition, supernatants from macrophages treated with PS contained TNF‐α, and their iNOS‐enzymatic activity was significantly increased. Thus, the tumouricidal activity induced by PS appeared to be mediated by the production of TNF‐α and nitrite. Treatment of macrophages with PS increased the expression of CD14, the receptor for lipolysaccharide (LPS)/LPS‐binding protein. Moreover, blocking antibody to CD14 abrogated partially TNF‐α and nitrite induction by PS, suggesting that the PS‐induced CD14 upregulation was correlated with secretion of TNF‐α and nitrite. Taken together, these results demonstrate that PS may induce macrophage‐secretory and cellular activities, in part, possibly via CD14‐dependent pathway.
Dendritic Cells Enriched from Swine Thymus Co‐express CD1, CD2 and Major Histocompatibility Complex Class II and Actively Stimulate Alloreactive T Lymphocytes
Authors: Salmon  , Johnson  , Germana  , Haller  , Sachs  , Leguern
Published: March 2003

Initial characterization and partial purification of thymic dendritic cells (DC) from miniature swine were carried out with the ultimate goal of using these cells to induce transplantation tolerance in this preclinical animal model. Immunohistochemical analysis of swine thymic tissue sections has shown DC to be large cells located in the medullary and the cortico‐medullary regions as evidenced by the presence of surrounding Hassal bodies. These cells exhibit membrane processes and express the CD1, granulocyte/macrophage (G/M), and major histocompatibility complex (MHC) class II surface antigens, as well as the S100 cytosolic and nuclear markers found in humans to be specific for DC. Dendritic cells were purified from thymi following collagenase treatment, Percoll gradient centrifugation, and adhesion steps to plastic. Cells similar in morphology and phenotype to those described in tissue sections were detected in the lighter density layers of the gradient and represented 0.02% of the starting cell number. Removal of plastic nonadherent cells showed enrichment levels similar to those reported for murine and human DC. Two‐colour flow cytometric analysis of purified pig DC identified these cells as MHC class IIhi, CD1+, CD2+, and G/M+. The dendritic nature of these cells was confirmed by their potent ability to stimulate alloreactive T lymphocytes. Modification of porcine thymic DC by transfer of allogeneic MHC genes and reinjection into the DC donor should permit testing of the role of this DC subset in the induction of transplantation tolerance.
Down‐Regulation of Interleukin‐12, Interleukin‐12R Expression/Activity Mediates the Switch from Th1 to Th2 Granuloma Response during Murine Schistosomiasis Mansoni
Authors: Todt J. C. , Whitfield J. R. , Ivard S. R. , Boros D. L.
Published: March 2003

In murine schistosomiasis mansoni the worm egg‐induced granulomatous inflammation is bi‐phasic: an initial Th1 type is subsequently switched to a Th2 type response. Analysis of the cellular, molecular base of the Th1‐associated response (5–6 weeks post infection) revealed mRNA messages for interleukin (IL)‐12 p40, IL‐12Rβ2 and interferon (IFN)‐γ in the granulomatous livers. When the Th2 type granulomas matured (8 weeks post infection) message expression weakened or became extinct. Macrophages of the Th1 type granulomas produced maximal amounts of IL‐12, but production diminished in the mature granulomas. A similar pattern of IL‐12 responsiveness of granuloma lymphocytes was observed. In vitro IL‐12 production by Th1 type granuloma macrophages was enhanced by tumour necrosis factor (TNF)‐α and IFNγ, whereas lymphocyte IL‐12 responsiveness was boosted only by TNF‐α. Both systems were down‐regulated by IL‐4 and IL‐10 cytokines. Treatment of mice with anti‐IL‐10 monoclonal antibodies (MoAb) between 6 and 7 weeks of the infection enhanced mRNA expression for IFN‐γ and IL‐12Rβ2, but not for IL‐12 p40. It is concluded that IL‐12 and IL‐12R expression and function regulate the Th1 phase of the liver granulomatous response. This phase is cross‐regulated by type‐2 cytokines especially IL‐10.
Prethymic Progenitors from the Avian Para‐Aortic Mesoderm Express GATA‐3 and Distinct chTcf Isoforms but Still Lack T‐Cell Receptor‐γ Rearrangements
Authors: Liippo J. , Koskela K. , Lassila O.
Published: March 2003

Haematopoietic precursors first colonizing the avian embryonic thymus are derived from the intraembryonic sites located around the dorsal aortae. These intraembryonic precursors have previously been demonstrated to include cells that harbour T‐cell progenitor capacity and express the Ikaros transcription factor, known to be a prerequisite for lymphocyte development. In this study, we further evaluated the properties of these prethymic cells. We show that early intraembryonic cells and prethymic progenitors already express the GATA‐3 transcription factor. The chicken homologue of T‐cell factor‐1, chTcf, is also detected in cells isolated from the avian para‐aortic region. However, these intraembryonic cells retain their T‐cell receptor gamma loci in germline configuration. Interestingly, chTcf was found to express different alternatively spliced isoforms during early ontogeny and thymic T‐cell development, which indicates developmentally regulated expression of chTcf variants. Taken together, these results demonstrate that, although the avian prethymic progenitor cells express T‐lineage‐associated transcription factors, they have not yet undergone TCR rearrangements. It is therefore suggested that activation of lineage‐associated genes is an early event in the generation of haematopoietic progenitor cells during ontogeny.
Key Sequences Involved in the Spreading of the Systemic Autoimmune Response to Spliceosomal Proteins
Authors: Monneaux F. , Muller S.
Published: March 2003

Immune spreading to multiple intracellular antigens is likely to be of primary importance in organ‐specific and systemic autoimmune diseases. A number of mechanisms by which immune spreading may occur from only a single autoreactive epitope have been proposed. Search for an initiator or early epitope thus represents an important area of investigation. For example, many studies have focused on the identification of epitopes recognized by the antibodies from both patients with systemic lupus erythematosus (SLE) and lupus‐prone mice. Recently, an autoepitope present in the 70K U1 ribonucleo protein (RNP) and recognized by CD4+ T cells from lupus mice has also been identified. Here, we analyze the results of B‐ and T‐cell‐epitope mapping studies of several RNPs present in the spliceosome and propose a model of epitope spreading. In this model, a consensus sequence (the RNP motif) conserved in many nuclear, nucleolar and cytoplasmic antigens, might play a role as ‘driver’ epitope. This hypothesis is based on the observation that this sequence is recognized by CD4+ T cells from lupus mice and is often targeted by autoantibodies, very early during the course of the disease. Targeting this region that is repeated in different self‐antigens, might represent an interesting strategy to interfere with the continuous T‐cell stimulation and exposure to specific antigens.
High Prevalence of Influenza Specific Antibody Secreting Cells in Nasal Mucosa
Authors: Brokstad K. A. , Cox R. J. , Eriksson J.‐C. , Olofsson J. , Jonsson R. , Davidsson Å.
Published: March 2003

Secretory immunoglobulin A (SIgA) provides the first line of defence against pathogens initiating infection via the mucosal route, e.g. the influenza virus. The aim of this study was to examine the basal level of influenza‐specific antibody‐secreting cell (ASC) in the local mucosa of the upper respiratory tract. Nineteen patients scheduled for tonsillectomy were enrolled for the study, and they had not experienced influenza during the previous year. Tonsils, blood, oral fluid and a nasal biopsy were sampled, and the basal levels of ASC and antibodies (Abs) were determined. We found low numbers of influenza‐specific ASC in the blood and tonsils, but there were about 10–100 times higher numbers of specific ASC in the nasal mucosa tissue despite no recent influenza exposure. Thus, the basal level of influenza‐specific ASC in the mucosa of the respiratory tract may be important in the protection against influenza infection.
Acute Phase Haemolysis in Chronic Cold Agglutinin Disease
Authors: Ulvestad E. , Berentsen S. , Mollnes T. E.
Published: March 2003

We previously described a paradoxical form of chronic cold agglutinin disease (CAD) in which haemolysis occurred during episodes of fever but only marginally during exposure to colds. In order to investigate the molecular basis for this response we performed a 12‐month prospective study of a patient with CAD and paradoxical haemolysis. Blood samples were collected monthly during health, and daily following hospitalization owing to hip fracture. During health we observed decreased levels of C3, undetectable C4, a non‐functional classical pathway and a normal alternative pathway. Increased concentrations of C1‐INH/C1rs complexes indicated continuous formation of C1‐antibody‐antigen complexes. There was a low‐grade temperature‐dependent fluctuating haemolysis as evidenced from measurements of lactate dehydrogenase. Following the hip fracture, the haemolysis increased. Levels of interleukin (IL)‐1β, IL‐6, interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α increased as did C1‐INH, C3, C4, CRP, and lactate dehydrogenase. The results support our hypothesis stating that paradoxical haemolysis in CAD is controlled by the availability of early classical pathway complement molecules and that haemolysis following acute phase responses occurs as a consequence of increased complement synthesis.
GVHD‐Associated Enteropathy and Endotoxemia in F1‐Hybrid Recipients of NK1.1‐Depleted Grafts
Authors: Ellison C. A. , Amadeo R. J. J. , Gartner J. G.
Published: March 2003

Our previous work using a C57BL/6→(C57BL/6 × DBA/2)F1‐hybrid model of acute GVHD showed that mortality can be completely prevented if grafts are depleted of NK1.1+ cells in vitro. To achieve this protection, it was necessary to inject the donors with polyinosinic:polycytidylic acid 18 h before the graft was harvested. In another study, we showed that interferon (IFN)‐γ production and lipopolysaccharide (LPS)‐induced tumour necrosis factor (TNF)‐α release are markedly reduced in these recipients, suggesting that this treatment abrogates the Th1‐mediated immune response that underlies the development of this disease. However, because it has also been hypothesized that cytotoxic NK1.1+ cells mediate injury to tissues targeted by the GVH reaction, we wished to determine whether NK1.1 depletion of the graft would also prevent the development of GVHD‐associated enteropathy and endotoxemia. We therefore induced GVH reactions in (C57BL/6 × DBA/2)F1 hybrids using either untreated grafts from unstimulated C57BL/6 donors, or NK1.1‐depleted grafts from poly I:C‐stimulated donors. We identified intestinal lesions morphologically in sections of ileum collected from each group of recipients but not in control mice. We also compared endotoxin levels in the sera. Our results indicate that GVHD‐associated enteropathy occurs in both groups of recipients, and that the levels of LPS in the sera do not differ significantly.
Effects of Indomethacin on the l‐selectin Expression in Humans
Authors: Dirnberger E. , Albinni S. , Röggla M. , Jilma B.
Published: March 2003

Based on an in vitro study and an uncontrolled in vivo trial we examined the effects of indomethacin on the expression of l‐selectin by leukocytes in healthy volunteers. Eight subjects received infusions of 0.7 mg/kg indomethacin and placebo t.i.d. (three times daily) in a randomized, controlled trial. Indomethacin decreased the mean fluorescence intensity of the l‐selectin expression on isolated neutrophils incubated with toxic indomethacin concentrations. However, indomethacin did not lower the l‐selectin expression in whole blood or in‐vivo. Thus, therapeutic doses of the cyclo‐oxygenase inhibitor indomethacin do not lower the l‐selectin expression on leukocytes. Hence, the inhibition of cyclo‐oxygenase cannot explain the previously observed dexamethasone‐induced decrease in l‐selectin.
Experimental IgG Antibody Production In vitro by Peripheral Blood and Tonsil Surface γ+ B Lymphocytes from Plasmodium falciparum‐Immune West Africans
Authors: Garraud O. , Diouf A. , Nguer C. M. , Tall A. , Marrama L. , Perraut R.
Published: March 2003

Antigen reactive B cells in tonsil specimens from teenagers from a region moderately exposed to P. falciparum were capable of being differentiated in vitro and producing specific immunoglobulin (Ig)G in up to 33% of individual experiments. Mononuclear cells or purified sγ+ CD19+ B cells from peripheral blood or tonsil specimens from P. falciparum‐immune Senegalese subjects produced antigen‐specific IgG upon appropriate stimulation in vitro. One fraction of this IgG was produced de novo by differentiated B cells and another fraction was likely bound on the surface of circulating or resident CD19+ sγ+ B cells which were found in significantly greater numbers in individuals from rural Senegal as compared to nonimmune European controls. This study further documents the baseline levels of in vitro driven anti‐P. falciparum IgG antibody production by mononuclear cells from blood and tonsils in immune populations exposed to P. falciparum differentially. Furthermore, this study demonstrates the relevance and potential utility of tonsils as a source of B lymphocytes to characterize further specific antibody responses to P. falciparum antigens in immune populations.
Extensive CDR3H Length Heterogeneity Exists in Bovine Foetal VDJ Rearrangements
Authors: Saini S. S. , Kaushik A.
Published: March 2003

Analysis of seven variable‐diversity‐joining (VDJ) gene rearrangements in B splenocytes from a 125‐day‐old bovine foetus revealed an extensive heavy‐chain complementarity‐determining region 3 (CDR3H) length variation (9–56 codons). Indeed, the global CDR3H size spectratyping of foetal VDJ rearrangements substantiated such an extensive heterogeneity and was comparable with that noted in peripheral B lymphocytes of adult cattle. These observations are in contrast to species such as humans with extensive germline combinatorial capability where shorter CDR3H length is noted early during B‐cell development. Exceptionally long CDR3H (as in adult cattle) was noted in two foetal VDJ rearrangements encoded by a single germline VH gene. Further, two VH genes (gl.110.20 and BF2B5) were preferentially expressed in the foetal VDJ rearrangements. The DH gene‐encoded CDR3H region of foetal VDJ rearrangements is remarkable for repetitive GGT (glycine) and TAT (tyrosine) codons that favour the recruitment of somatic hypermutations. It appears that closely related germline DH genes, preferentially used in the hydrophilic reading frame, encode varying CDR3H lengths early during B‐cell ontogeny in cattle. A comparison of germline and expressed VH genes, especially in the CDR1 and CDR2, confirms that somatic hypermutations contribute to immunoglobulin (Ig)M antibody diversification in cattle. The biased nucleotide base use and high occurrence of ‘hot‐spot’ triplet (AGPy; AG pyrimidine base) in the CDRs predisposes to somatic hypermutations. Overall, these observations suggest that extensive CDR3H length heterogeneity, including the generation of exceptionally long CDR3H (up to 56 amino acids), and somatic hypermutations contribute to IgM antibody diversification in cattle. The extensive CDR3H length heterogeneity early during the B‐cell development may compensate for constraints imposed on antibody diversification owing to the limited germline sequence diversity of genetic elements in cattle.
Complement Activation Mediated by Mannan‐Binding Lectin in Plasma from Healthy Individuals and from Patients with SLE, Crohn's Disease and Colorectal Cancer. Suppressed Activation by SLE Plasma
Authors: Zimmermann‐Nielsen E. , Baatrup G. , Thorlacius‐Ussing O. , Agnholt J. , Svehag S.‐E.
Published: March 2003

We have developed a method for quantitating mannan‐binding lectin (MBL)‐induced activation of the complement system (MBL‐C4‐AC) in human plasma. This method and an assay for MBL concentration were applied to plasma samples from healthy individuals and patients with systemic lupus erythematosus (SLE), Crohn's disease (CD) and colorectal cancer (CRC). The MBL concentration was measured by an enzyme‐linked immunosorbent assay (ELISA) using monoclonal anti‐MBL‐antibodies and MBL‐C4‐AC by an ELISA using solid‐phase mannan, incubating with plasma samples and quantitating the complement (C) activation by the use of antibodies against the C split‐products C4b/C4c. The MBL concentration was nonsignificantly elevated in plasma from SLE‐patients, whereas MBL‐C4‐AC was suppressed ( P < 0.04). There was no correlation between MBL concentration and MBL‐C4‐AC in plasma from SLE‐patients. In contrast, a significant correlation was found between the MBL concentration and MBL‐C4‐AC in plasma from healthy individuals. The C4 concentration was significantly reduced ( P < 0.002) in plasma from the SLE patients and showed a significant correlation to MBL‐C4‐AC. The MBL‐C4‐AC assay was highly effective in discriminating the SLE patients from the other patient groups and healthy individuals.