bluuebunny/crossref_metadata_2025 huggingface dataset:
Interleukin‐12 Induces Efficient Lysis of Natural Killer‐Sensitive and Natural Killer‐Resistant Human Osteosarcoma Cells: the Synergistic Effect of Interleukin‐2
Authors: Mariani  , Meneghetti  , Tarozzi  , Cattini  , Facchini
Published: March 2003

Previously we demonstrated that some osteosarcoma cell lines varied greatly in their susceptibility to natural killer (NK) cell lysis in vitro. The expression of CD54 and CD58 adhesion molecules on their surface appeared to influence their vulnerability, and the tumour necrosis factor‐α (TNF‐α)‐induced positive modulation of CD54 increased osteosarcoma susceptibility in vitro. This study investigated whether peripheral blood mononuclear cells from normal healthy donors could be activated by interleukin (IL)‐12 and IL‐2, separately or in combination, to lyse osteosarcoma cell lines in vitro, as evaluated by using a microcytotoxicity test. In addition, we analysed (by flow cytometry) whether this function correlated with modifications of the CD2, CD11a, CD11b and CD18 molecules, which are involved in the adhesion of effector cells to the counter‐receptors (CD54 and CD58) on osteosarcomas. This study demonstrates that incubation with IL‐12 and/or IL‐2 triggered NK cell cytolytic activity against osteosarcoma targets and that cytolytic activity was enhanced to a greater extent when lymphocytes were incubated simultaneously with a combination of IL‐12 and IL‐2. The density of CD18 and CD2 molecules involved in NK adhesion was also up‐modulated following cytokine incubation. These changes in the density of adhesion molecules can be involved in the increased lytic activity of effector lymphocytes and in the modification of their binding capacity to osteosarcoma target cells.
Differences in the Ligand Specificity between CD1d‐Restricted T Cells with Limited and Diverse T‐Cell Receptor Repertoire
Authors: Makowska  , Kawano  , Taniguchi  , Cardell
Published: March 2003

The natural killer (NK) T‐lymphocyte population consists of two subsets utilizing a diverse and restricted T‐cell receptor (TCR) repertoire, respectively. Both populations have been shown to include autoreactive cells. NKT cells carrying restricted Vα14(AV14S1)Jα281/Vβ8.2(BV8S2A1) TCR have been shown to recognize α‐galactosylceramide (αGalCer) presented in the context of murine CD1d. In this study we screened a set of murine CD1d‐autoreactive T‐cell hybridomas with diverse TCR for their reactivity with several glycosylated variants of ceramide, including αGalCer. These hybridomas showed a different pattern of reactivity to CD1d‐expressing antigen‐presenting cells (APC) and were not reactive with any of the tested variants of ceramide. A second set of hybridomas had been selected for expression of Vα14 and Vβ8.2 TCR chains. These cells responded to αGalCer presented on CD1d, but were only weakly reactive to syngeneic splenocytes or CD1d‐transfected cells. Their fine specificity in the response to glycosylation variants of ceramide demonstrated a homogenous reactivity pattern, including reactivity to α‐galactosylsphingosine, the variant of αGalCer with truncated fatty acyl chain. These findings underline the differences in ligand specificity between the two subsets of CD1d‐restricted NKT cells, and demonstrate a similarity in reactivity among the hybridomas using the Vα14‐Jα281/Vβ8.2 TCR.
Changes in Cytokine Production In Vitro during the Early Phase of Birch‐Pollen Immunotherapy
Authors: Movérare  , Elfman  , Björnsson  , Stålenheim
Published: March 2003

The kinetics of the immunological mechanisms during allergen‐specific immunotherapy (IT) has not been thoroughly evaluated. In this investigation we study the changes in T‐cell responses during the early phase of IT. Ten patients (IT group) with birch‐pollen allergy were treated with conventional IT. Blood samples were collected at regular intervals for specific immunoglobulin (Ig)E measurements and preparation of peripheral blood mononuclear cells (PBMC). Seven allergic control patients (AC group) were included during the subsequent birch‐pollen season. The PBMC were stimulated with birch‐pollen extract or tetanus toxoid (TT) and mitogens. After a short decrease, probably owing to seasonal variation, the birch‐pollen‐specific proliferation and the interleukin (IL)‐4, IL‐5, and IL‐10 production significantly increased when reaching the maintenance dose and during the subsequent pollen season. The increase in IL‐4 correlated with a temporary increased serum level of birch‐pollen‐specific IgE. Interestingly, also the TT‐specific response was affected by IT, resulting in weaker, but in time similar, changes in proliferation and cytokine production as in the birch‐pollen‐specific response. We speculate that the early phase of IT might lead to systemic changes in the capacity of Th2‐like cytokine production, and that the early increase in allergen‐specific IgE is a consequence of enhanced IL‐4 production.
Structure‐Function Effects in Primary Immunodeficiencies
Authors: Korpi  , Väliaho  , Vihinen
Published: March 2003

Several immunodeficiency‐related genes have been identified and a large number of mutations in these genes. Currently, a genetic defect has been determined in more than 2000 patients. Only recently has it become possible to address structure‐function effects of these mutations in the corresponding proteins. The consequences of mutations in structure are discussed for Btk in X‐linked agammaglobulinemia (XLA), Jak3 in T−B+ severe combined immunodeficiency (SCID), p47phox and p67phox in autosomal chronic granulomatous disease (CGD) and SH2D1 A in X‐linked lymphoproliferatine disease (XLP). The experimental and homology modelling derived structures were used to analyze mechanisms related to these diseases.
Impaired CD40‐Signalling in CD19‐Deficient Mice Selectively Affects Th2‐Dependent Isotype Switching
Authors: Gärdby E. , Chen X.‐J. , Lycke N. Y.
Published: March 2003

Activation of B lymphocytes involves binding of antigen to the specific receptor and signalling through several membrane coreceptors, of which CD19 has been found to play a pivotal role as a response regulator. Although previous studies in CD19 gene knockout mice have demonstrated that antibody responses to T‐cell‐dependent antigens are strongly impaired in the absence of this coreceptor, little is known about the consequences of CD19 deficiency for the interaction between T and B cells. Here we report that Th2 co‐ordinated B‐cell differentiation is selectively impaired in CD19‐deficient mice in response to mucosal or systemic immunizations or following an intestinal infection with Nippostrongylus brasiliensis. Whereas immunoglobulin (Ig)G1 or IgE antibody responses were low or absent, IgG2a responses were normal. The selective defect was not caused by a poor Th2‐development or interleukin (IL)‐4 responsiveness in CD19‐deficient mice. Rather, it was the result of an impaired Th2–B cell interaction, owing to a substantially reduced ability to signal via CD40 in CD19‐deficient B cells. Thus, our study in CD19‐deficient mice suggests that CD40L–CD40‐interactions are more important for Th2 than for Th1 co‐ordinated B‐cell differentiation.
Distinct Amplification of the C5a‐Receptor Pathways in Normodense and Hypodense Eosinophils of Patients with Atopic Dermatitis
Authors: Czech W. , Dichmann S. , Herouy Y. , Rheinen H. , Elsner J. , Kapp A. , Norgauer J.
Published: March 2003

In patients with atopic dermatitis two different types of blood eosinophils with distinct density can be isolated. The normodense cells represent the huge majority in count, whereas the hypodense eosinophils are characterized by higher effector activity. To understand the altered functional responsiveness of these two cell subtypes, the expression of C5a receptors as well as C5a‐induced signal pathways and the production of reactive oxygen metabolites have been analyzed. Chemiluminescence measurements revealed significant higher production of reactive oxygen metabolites in hypodense eosinophils in comparison to normodense cells. However, no difference in the expression level of C5a receptors as well as in the C5a‐induced Ca2+‐transients between normodense and hypodense eosinophils were found. In contrast, hypodense eosinophils showed a significantly higher actin polymerization response and phosphatidylinositol 4,5 bisphosphate 3‐kinase activation after stimulation with C5a than normodense eosinophils. Therefore, normodense and hypodense eosinophils from the blood of patients with atopic dermatitis are characterized by differential amplification of C5a‐receptor signal pathways, which might explain the differences in their proinflammatory activity.
Molecular Modelling and Endoplasmic Reticulum Retention of Mutated TCR/CD3 Complexes
Authors: Arnaud J. , Erard M. , Martin E. , Llobera R. , Gouaillard C. , Constans J. , Rubin B.
Published: March 2003

T cell receptor (TCR)/CD3 complex assembly takes place in the endoplasmic reticulum (ER). Normal TCR/CD3 complexes egress from the ER to the cis‐Golgi, where the interaction with ζ2 homodimers occurs. This interaction leads to further uncontrolled transport of TCR/CD3/ζ molecules to the cell surface. The purpose of the present experiments was to determine firstly the basis for the impact of the phe195/216 = > val mutations on TCR/CD3 expression in Jurkat cells, and secondly why mutated J79‐cell TCRαβ/CD3 hexamers are prevented from interacting with ζ2 homodimers. We found that phe = > val mutations cause serious perturbations in a so far undefined hydrophobic area formed by the two phe195/216 on β‐strand F and aromatic/large hydrophobic amino acids on neighboring β‐strands B and A in Cα and Cβ domains, respectively. In addition, TCR/CD3 hexamers and ζ2 homodimers colocalize in normal Jurkat T cells, in revertant J79r58 cells, and in J79 cells transfected with wild‐type TCRα cDNA but not in J79 mutant cells (confocal microscopy). Furthermore, mutated TCR/CD3 complexes seem to be actively retained in the ER in J79 cells but not in revertant J79r58 cells by a nondominant mechanism. We propose that a hitherto undefined ER‐retention molecule controls both the protein structure and egress of TCR/CD3 complexes from the ER of αβ and γδ T cells.
The Effect of Cytokines on the Activation‐Induced Apoptosis of B Cells in Autoimmune NZB X NZW F1 Mice
Authors: Chen Y.‐Y. , Suen J.‐L. , Wu W.‐M. , Chiang B.‐L.
Published: March 2003

Programmed cell death (apoptosis) is an essential process in the development of various tissues and its involvement has been proposed for the elimination of self‐reactive immature T and B lymphocytes when self antigens are first encountered. In order to further investigate the role of apoptosis in the pathogenesis of autoimmune disease, the apoptosis of lipopolysaccharide (LPS)‐activated B cells, peritoneal cells from NZB x NZW F1 (NZB/W F1) mice and nonautoimmune BALB/c mice were assayed using an in vitro culture system. Splenic B cells were isolated and then stimulated with LPS before further activated with crosslinking antiµ antibody. In addition, the apoptosis of peritoneal cells induced by crosslinking antiµ antibody was also analyzed. The data revealed that the specific apoptosis of both activated B cells and peritoneal cells induced by crosslinking antiµ antibody was very similar comparing NZB/W F1 and nonautoimmune BALB/c mice. This activation‐induced B‐cells apoptosis could be rescued, however, with the addition of cytokines such as interleukin (IL)‐5 or IL‐10, to the culture. The results suggest that there is no endogenous defect in the apoptosis of activated B cells for autoimmune NZB/W F1 comparing nonautoimmune BALB/c mice. Notably, however, abnormally high levels of the type 2 T helper (Th2)‐related cytokines such as IL‐5 or IL‐10 may play an important role in the abnormal expansion of activated B cells in autoimmune NZB/W F1 mice.
Hereditary Human Complement C3 Deficiency Owing to Reduced Levels of C3 mRNA
Authors: Ulbrich A. G. , Florido M. P. C. , Nudelman V. , Reis E. S. , Baracho G. V. , Isaac L.
Published: March 2003

An 8‐year‐old son (L.A.S.) of consanguineous parents, presented recurrent bacterial infections, vasculitis and extremely low levels of serum C3 (0.15 µg/ml). The classical and alternative pathway haemolytic activities and the generation of opsonins and chemotactic factors derived from the activation of the complement system were markedly affected in the proband's serum. An in vitro addition of purified C3 restored the classical pathway‐dependent haemolytic activity of his serum. Autoradiographs of the proband's lipopolysaccharide (LPS)‐stimulated and 35S‐labelled fibroblast supernatants after that the SDS‐PAGE revealed no C3 α or β chains. The amount of C3 mRNA synthesized by the proband's fibroblasts, as evaluated by reverse transcription–polymerase chain reaction (RT–PCR) assays, was greatly reduced.
Immunostimulatory DNA from Paracoccidioides brasiliensis Acts as T‐Helper 1 Promoter in Susceptible Mice
Authors: Souza M. C. , Corrêa M. , Almeida S. R. , Lopes J. D. , Camargo Z. P.
Published: March 2003

Th1 immune responses afford protection against some pathogens like the fungus P. brasiliensis (P.b.), ethiological agent of Paracoccidioidomycosis (PCM). It is well known that nonmethylated CpG sequences from bacterial DNA have immunomodulatory properties and can be used as a Th1‐promoting adjuvant. By analyzing the available gene sequences of P.b. we observed a high number of unmethylated CpG dinucleotides. In a murine model of the PCM infection, the isogenic mouse strain known to be susceptible presents a predominant Th2 pattern. In order to access the possibility of the genomic DNA to act as a Th1‐promoting adjuvant, in vitro assays were made and indicated a significant increase in phagocytosis when the macrophages were stimulated with DNA from P.b. and in vivo assays of a decreased production of antibodies antigp43, the main antigen of the PCM system. The analysis of the antibody isotypes and the cytokine production suggested a Th1 modulation in the susceptible animals. Thus, when mice were infected with fungus plus synthetic oligodeoxynucleotide (ODN), made from the available sequence of gp43, a decrease in the fungus dissemination was observed. Results herein described suggest that genomic DNA from P.b. could have a immunostimulatory function as a Th‐1‐promoting adjuvant in susceptible mice.
Liberation of Soluble Proteins from Live and Dead Mycobacterial Cells and the Implications for Pathogenicity of Tubercle Bacilli
Authors: Wiker H. G.
Published: March 2003

Soluble proteins liberated from live M. tuberculosis are translocated through the cytoplasmic membrane to a ‘periplasmic space’. For further export of proteins across the outer permeability barrier, it is necessary to postulate an excretion mechanism possibly involving some kind of porin. Observations of the repertoire of proteins in culture filtrates after liquid culture of M. tuberculosis show that a large repertoire of various kinds of proteins cross the outer permeability barrier of tubercle bacilli indicating that the excretion mechanism has a wide range of specificities for proteins. Culture filtrates of tubercle bacilli almost always contain both truly secreted proteins and cytoplasmatically‐derived proteins. It is questionable whether cytoplasmic proteins can cross an intact cytoplasmic membrane. The simplest explanation for the appearance of cytoplasmic proteins in culture filtrates of tubercle bacilli would be that they are released after disintegration of the cytoplasmic membrane in dying or dead bacilli. Tubercle bacilli armed with secreted factors that may specifically inhibit innate and adaptive immune responses, excrete these from the periplasmic space of live bacilli. Unspecific in its character, the excretion mechanism also liberates proteins that are essential for building and maintaining the cell wall, thereby reducing the effectiveness of this process. This may be part of the explanation why M. tuberculosis and other pathogenic mycobacteria grow so slowly. Finally, it may be postulated that dormant or latent tubercle bacilli use their repertoire of secreted proteins to control their intracellular habitat and that bacterial cytoplasmic proteins would not be liberated from such bacilli. The consequence would be that only immune responses to secreted proteins would be effective for elimination of the dormant stage of infection. In a situation with active infection there will be considerable growth and turnover of bacilli with liberation of all kinds of immunogenic substances from the bacilli. In this situation immunity against cytoplasmic proteins would also be effective and immunity to cytoplasmic proteins should also be effective for control of the reactivation of latent disease because as soon as the bacilli start to grow there will also be a subpopulation of dead bacilli on the arena.
Adhesive Interactions between Human NK Cells and Porcine Endothelial Cells
Authors: Schneider M. K. J. , Forte P. , Seebach J. D.
Published: March 2003

Human natural killer (NK) cells are able to adhere to xenogeneic porcine endothelial cells (EC) and evidence from in vitro studies as well as animal models suggests a potential role for NK cells in the cellular recognition and damage of porcine xenogeneic tissues. One possible explanation for the observed NK cell‐mediated xenogeneic cytotoxicity against porcine EC is the molecular incompatibility between porcine major histocompatibility complex (MHC) class I molecules and MHC‐specific inhibitory receptors on human NK cells. In this review we attempt to summarize the current knowledge concerning adhesive interactions between human NK cells and porcine EC under special considerations of the cross‐species receptor–ligand interactions. Methodological differences in assessing adhesion between various studies are reviewed and comparisons to the syngeneic/allogeneic adhesion mechanisms are made. Finally, the therapeutic potential of blocking antibodies and transgenic HLA expression in preventing NK‐cell adhesion and xenogeneic cytotoxicity is discussed.
Antisense Phosphorothioate Oligonucleotides to the p65 Subunit of NF‐κB Abrogate Fulminant Septic Shock Induced by S. typhimurium in Mice
Authors: Schlaak J. F. , Barreiros A. P. , Pettersson S. , Schirmacher P. , Meyer Zum Büschenfelde K.‐H. , Neurath M. F.
Published: March 2003

The aim of this study was to characterize the functional relevance of the transcription factor NF‐κB in the pathogenesis of septic shock. BALB/c mice were infected with two wild‐type (WT 1, WT 2) strains of S. typhimurium that induce NF‐κB or an escape variant that lacks this ability (P21) at a dose of 1 × 109/animal, respectively. Furthermore, wild‐type infected mice were treated with antisense oligonucleotides directed against NF‐κB 24 h before and 3 or 6 h after infection, while mismatched oligonucleotides were used as controls. Subsequently, the clinical course, histological and immunological alterations were monitored. Infection with WT 1 and WT 2 strains led to lethal septic shock within 24–36 h. In contrast, infection with the P21 variant was not followed by fulminant septic shock. Treatment with specific antisense oligonucleotides against the p65 subunit of NF‐κB 24 h before infection prevented the development of fulminant, lethal septic shock and was associated with a significant increase of survival. After 20 h, markedly depressed serum levels of interferon (IFN)‐γ and interleukin (IL)‐6 but not IL‐10 and tumour necrosis factor (TNF)‐α were observed in p65 antisense‐treated compared to mismatched‐treated animals. These data show that the ability of S. typhimurium to induce lethal septic shock is critically dependent on their capacity to induce NF‐κB.
The Biological Activity of Serum IgE Changes over the Course of a Primary Response
Authors: Mitchell A. J. , Moss N. D. , Collins A. M.
Published: March 2003

Mast‐cell degranulation is triggered by the bridging of Fc receptor‐bound antigen‐specific immunoglobulin IgE on the cell surface. In vitro experiments suggest that antibody affinity and nonspecific IgE may affect the mast‐cell function, however, their importance in vivo is unclear. Investigations of the effects of these parameters on mast‐cell sensitization were therefore carried out in a rat immunization model in which the IgE response is transient and peaks on days 10–15. Between these two timepoints, significant changes in the level of specific IgE were not observed, but the avidity of specific IgE increased (P < 0.05). Total serum IgE peaked on day 10 and slowly declined, with the relative proportion of specific to total IgE increasing from day 10–15 (P < 0.05). Despite similar levels of antigen‐specific IgE, increasing avidity and an increased proportion of specific IgE between days 10 and 15, the biological activity of IgE in the serum peaks on day 10 and declines rapidly, dropping around seven‐fold by day 15 (P < 0.001). Mechanisms that could explain this finding, such as differential expression of IgE isoforms and changes in the fine specificity of the IgE response, are discussed.
In vitro Effect of Bioactive Compounds on Influenza Virus Specific B‐ and T‐Cell Responses
Authors: Boon A. C. M. , Vos A. P. , Graus Y. M. F. , Rimmelzwaan G. F. , Osterhaus A. D. M. E.
Published: March 2003

In vitro studies have demonstrated positive effects of bioactive compounds on several functions of the immune system. In the present study, 25 of such compounds were tested for their immune modulating properties on influenza virus specific human B‐ and T‐cell responses in vitro. One of these compounds, N‐acetyl‐l‐cysteine was shown to increase influenza virus specific lymphocyte proliferation and interferon(IFN)‐γ production at a concentration of 1.0 mmol/l. Furthermore, N‐acetyl‐l‐cysteine was found to enhance a specific activity of two influenza specific CD8+ cytotoxic T‐lymphocyte clones directed towards HLA‐A*0201 and HLA‐B*2705 restricted epitopes. A second compound, chlorogenic acid, was shown to enhance antigen specific proliferation of lymphocytes in three out of four donors, at concentrations of 10–50 µmol/l. Neither of the two compounds exhibited a positive effect on the production of influenza virus specific antibodies by human peripheral blood mononuclear cells in vitro.
Generation of Antibodies to the Signal Peptide of the MPT83 Lipoprotein of Mycobacterium tuberculosis
Authors: Harboe M. , Whelan A. O. , Ulvund G. , McNair J. , Pollock J. M. , Hewinson R. G. , Wiker H. G.
Published: March 2003

The mpt83 gene (Rv2873) encodes the exported MPT83 lipoprotein of Mycobacterium tuberculosis. The corresponding identical mpb83 gene of Mycobacterium bovis is expressed to varying extents in different substrains of M. bovis Bacille Calmette Guerin (BCG), BCG Tokyo and BCG Moreau being high producers and BCG Danish 1331, a low producer of the MPB83 protein. Immunization with the 13‐mer N‐terminal part of the signal peptide of MPT83, MINVQAKPAAAASC, coupled to keyhole limpet haemocyanin (KLH) through the added C‐terminal cysteine resulted in rapid antibody formation monitored by enzyme‐linked immunosorbent assay (ELISA) with free immunizing peptide on the solid phase. In ELISA, with four 20‐mer overlapping peptides covering the N‐terminal part of the MPT83 sequence, three polyclonal rabbit antisera reacted only with the N‐terminal peptide. Antigenic signal peptide could not be detected in sonicates of BCG Tokyo and BCG Moreau. After SDS‐PAGE and blotting, the antibodies reacted with sonicates of recombinant Escherichia coli containing the entire mpt83 gene including the signal sequence, but not with the 22 kDa form of native MPB83 purified from BCG culture filtrate. In partition chromatography the recMPT83 partitioned in the water phase while 26 kDa MPB83 in BCG culture filtrate partitioned in the lipid phase confirming that lipidation at the N‐terminal cysteine residue occurs after the splitting of the polypeptide chain by signal peptidase II.
Primary Immunodeficiency Diseases: Natural Mutant Models for the Study of the Immune System
Authors: Fischer A.
Published: March 2003

Primary immunodeficiency diseases represent many natural mutant models for the analysis of many aspects of immunology. Examples dealing with T‐ and B‐cell receptors are herein discussed. They also represent privileged models in medicine, because well characterized monogenic inherited diseases can in some instances be viewed as good targets for gene therapy as shown here for severe combined immunodeficiency (SCID).
In Vitro and In Vivo Inhibition of Immunoglobulin Secretion by the Immunosuppressive Compound HR325 is Reversed by Exogenous Uridine
Authors: Thomson T. A. , Spinella‐Jaegle S. , Francesconi E. , Meakin C. , Millet S. , Flao K. L. , Hidden H. , Ruuth E.
Published: March 2003

The objective was to demonstrate that the immunosuppressive agent HR325 (an inhibitor of dihydroorotate dehydrogenase, DHODH) inhibits immunoglobulin (Ig) secretion both in vitro and in vivo and that this effect can be reversed with exogenous uridine.

In vitro
, Ig secretion from mouse splenocytes was induced by lipopolysaccharide (LPS) for 5 days. HR325 inhibited the secretion of IgM and IgG with IC
50
values of 2.5 and 2 µ
m
, respectively. Adding uridine (50 µ
m
) increased these values to 70 and 60 µ
m
, respectively. Similarly, the IC
50
values of another DHODH inhibitor, brequinar sodium, were also attenuated by uridine from 0.04 to 1 µ
m
for IgM, and 0.012 to 10 µ
m for IgG. HR325 (and a structural analogue A771726) inhibited LPS‐induced kappa light‐chain cell surface expression on 70Z/3 cells, a property also reversed by uridine.

In vivo
, the secondary anti‐sheep red blood cell (SRBC) antibody response (unaffected by uridine alone) was inhibited by HR325 and brequinar with respective ID
50
values of 38 and 0.6 mg/kg per oral (p.o.). Immunosuppression with HR325 (50 mg/kg) and brequinar (1 mg/kg) was abrogated by uridine. Uridine had no effect on cyclophosphamide‐induced (10 mg/kg p.o.) immunosuppression. These data are consistent with the immunosuppressive mechanism of HR325 being the result of pyrimidine depletion
in vitro
and
in vivo .
Dendritic Cells Present an Intracellular Viral Antigen Derived from Apoptotic Cells and Induce a T‐Cell Response
Authors: VAN ZANTEN J. , HOSPERS G. A. P. , HARMSEN M. C. , THE T. H. , MULDER N. H. , DE LEIJ L. F. M. H.
Published: March 2003

We investigated if dendritic cells (DCs) were able to present intracellularly located antigens derived from apoptotic cells to T cells, thereby inducing a CD4+ and a CD8+ response. A transfected cell line with the cytomegalovirus‐derived protein pp65 was triggered to go into apoptosis by ultraviolet B (UVB) irradiation, and after the uptake of apoptotic cells by DC, the activation and proliferation of T cells were determined. We found that DC efficiently phagocytosed apoptotic cells and induced a CD4+ and a CD8+ T‐cell response specific for the viral protein pp65. This mechanism can be useful for vaccination studies to induce an antiviral immune response.
The Study of T‐Cell Activation in Peripheral Blood and Spleen of Hepatosplenic Patients Suggests an Exchange of Cells Between these Two Compartments in Advanced Human Schistosomiasis Mansoni Infection
Authors: TEIXEIRA‐CARVALHO A. , MARTINS‐FILHO O. A. , ANDRADE Z. A. , CUNHA‐MELLO J. R. , WILSON R. A. , CORRÊA‐OLIVEIRA R.
Published: March 2003

A histopathological and immunophenotypic study was performed on the spleen of patients with hepatosplenic (HS) schistosomiasis mansoni. Morphological data demonstrated that all HS patients presented features related to Schistosoma mansoni‐induced splenomegaly, such as red pulp congestion and atrophy/hyperplasia of white pulp. The morphological diversity of the white pulp seems to be associated with the expansion of activated CD4+ T‐cell subpopulation. The data obtained suggest that the spleen is an important site for T‐cell activation during severe chronic infection with S. mansoni. In addition, we have compared the cell populations/subpopulations presented in the peripheral blood with that observed in the spleen of patients with HS schistosomiasis mansoni. We observed a significant increase in the percentage of activated CD4+HLA–DR+ and CD8+HLA–DR+ T cells in both the spleen and the peripheral blood of HS patients in comparison with noninfected individuals (NOR). These data suggest an exchange of cells between these two compartments. However, we observed normal expression of the CD28 molecule by CD8+ T cells in the spleen, despite a lower percentage of these cells in the peripheral blood. This finding supports the hypothesis that the decrease in CD28 expression, by CD8+ cells, is an event that takes place outside the spleen during human schistosomiasis infection. The most important conclusion is the fact that the analysis of T‐cell activation in the peripheral blood reflects the major immunological reactivity that occurs in the spleen during human schistosomiasis and that the morphological aspects of the spleen may reflect the functional activity of T cells. The specificities of T cells and the roles they may play in the pathogenesis during chronic schistosomiasis now need to be determined.
Activated T Cells in the Surface Secretion on the Adenoid – a Flow Cytometric Study
Authors: IVARSSON M. , LUNDIN B. S. , LUNDBERG C.
Published: March 2003

We previously demonstrated the presence of leucocytes in the adenoid surface secretion with the ability of immunoglobulin A (IgA), IgM and IgG production as well as production of cells with phagocytic capacity. In the present study, we investigated the presence of activated T cells in the secretion.

Adenoid surface secretion from 12 children subjected to adenoidectomy was obtained with an imprint method. From six children, peripheral blood was also obtained. By flow cytometry, the number of lymphocytes, granulocytes, epithelial cells and red blood cells was analysed as well as the expression on lymphocyte subsets of the following antigens: CD3, CD4, CD8, CD19, CD25, CD38, CD45RO, CD45RA, HLA‐DR, TcRgd, CD161 and l‐selectin.

The majority of T cells were activated and to a significantly higher degree were CD45RO+, CD161+ and l‐selectin−, as compared with the corresponding peripheral blood. The median percentage of B cells and T cells in the secretion were 81 and 13%, respectively.

In conclusion, the proportion of B and T cells in the adenoid surface secretion is significantly different as compared with the peripheral blood. The T cells in the adenoid surface secretion are to a high degree activated. The results suggest that the leucocytes in the surface secretion are part of the mucosal defence.
Successful Generation of Sperm Protein 17 (Sp17)‐Specific Cytotoxic T Lymphocytes from Normal Donors: Implication for Tumour‐Specific Adoptive Immunotherapy Following Allogeneic Stem Cell Transplantation for Sp17‐Positive Multiple Myeloma
Authors: CHIRIVA‐INTERNATI M. , WANG Z. , SALATI E. , WROBLEWSKI D. , LIM S. H.
Published: March 2003

Sperm protein 17 (Sp17) is a highly immunogenic cancer‐testis antigen expressed by tumour cells from up to 30% of patients with multiple myeloma (MM). We recently successfully generated Sp17‐specific human leucocyte antigen (HLA)‐A1 and B27‐restricted cytotoxic T lymphocytes (CTLs) from the peripheral blood of a healthy donor. Because CTLs were able to kill HLA‐matched fresh myeloma cells, it may be possible to generate and administer myeloma‐specific donor T cells to MM patients following allogeneic stem cell transplantation to enhance graft‐versus‐myeloma (GVM) without inducing graft‐versus‐host disease (GVHD). To determine how widely applicable this approach is, we have determined the ability to generate Sp17‐specific CTLs from four consecutive healthy donors with other HLA class I phenotypes. We found that Sp17‐specific HLA class I‐restricted CTLs could be easily generated from all four donors. Sp17‐specific CTLs were primarily CD8 in phenotype and produced interferon‐γ and very little interleukin‐4. These T cells killed target cells primarily via the perforin‐mediated route. These results therefore suggest that myeloma‐specific donor T‐cell infusion that targets Sp17 to selectively enhance GVM could be applicable to patients with Sp17+ MM.
DNA Immunization of Mice against the VP1 Capsid Protein of Coxsackievirus B4
Authors: Toniolo A. , Falcone V. , Bernasconi C. , Basolo F. , Speziale P. , Onodera T.
Published: March 2003

The protective activity of a DNA plasmid encoding the immunodominant capsid protein VP1 of coxsackievirus B4 (CBV‐4) was studied in BALB/c mice. The plasmid pCI‐B4‐1‐c – which gave the highest expression level of VP1 in cultured monkey and human cells – was chosen for immunization. Two injections of pCI‐B4‐1‐c (1 month apart) into the regenerating mouse muscle tissue induced a specific antibody response to CBV‐4, as shown by immunoenzyme and neutralization assays. Upon challenge with live CBV‐4, the mortality rate of mice vaccinated with the recombinant plasmid was significantly reduced (21% versus >58%) as compared with that of mice that had been either nontreated or injected with a control plasmid devoid of the insert. The VP1‐based vaccine, however, did not provide complete protection as – after virus challenge – moderate viraemia occurred together with modest plasma elevations of pathogenesis‐related enzymes (amylase and creatine kinase). Yet, immunofluorescence of the small intestine and heart did confirm the protective effect of the VP1‐encoding vaccine. In order to obtain a more complete protection against CBV‐4, it may be beneficial to immunize mice with combinations of separate DNA plasmids encoding not only VP1 but also the VP2 and VP3 capsid proteins.
Influence of the Polyclonal Activation Induced by Plasmodium chabaudi on Ongoing OVA‐Specific B‐ and T‐Cell Responses
Authors: SARDINHA L. R. , D'IMPÉRIO LIMA M. R. , ÁLVAREZ J. M.
Published: March 2003

Infection by Plasmodium chabaudi results in polyclonal activation, massive proliferation and differentiation of lymphocytes with parasite‐unrelated specificities. To verify if polyclonal activation includes experienced B and T lymphocytes and if it modifies pre‐established cytokine and Ig‐isotype patterns, mice were immunized with ovalbumin (OVA) in alum, a condition that favours T helper 2/immunoglobulin G1 (Th2/IgG1) responses, and infected with P. chabaudi 7 or 80 days later. Polyclonal activation markedly increased the number of anti‐OVA Ig‐secreting cells in the spleen, an effect more patent in mice infected 7 days after OVA immunization, but also evident in mice infected after 80 days. The Ig‐isotype profile predefined by immunization was not qualitatively modified by polyclonal activation. Thus, although P. chabaudi infection preferentially induces IgG2a, the expanded anti‐OVA response is dominated by IgG1. Polyclonal expansion of the anti‐OVA response did not yield an enlarged memory B‐cell pool that could be recalled months later by OVA boosting. Moreover, polyclonal activation of anti‐OVA IgG1‐secreting cells did not increase this antibody in serum, a probable consequence of the high Ig turnover observed during infection. When OVA‐specific T‐cell cytokines were evaluated, we observed an increase of both interleukin‐4 (IL‐4) and interferon‐γ (IFN‐γ) in mice infected 7 days after immunization, whereas in those infected after 80 days, only IL‐4 was augmented. These results suggest that polyclonal activation expands experienced B‐ and T‐cell compartments, preserving their antibody and cytokine patterns.
Analysis of Complement‐Bound HCV Complexes Using a Novel Immuno‐Capture RT‐PCR Method
Authors: Zhu H. , Wang S. Y. , Zhang J. Y. , Lian Q. Z. , Peng X. X.
Published: March 2003

Recently, more and more evidence has supported the hypothesis that liver cell injury was immune‐mediated in patients with hepatitis C virus (HCV) infection, and that circulating immune complexes (CICs) might play a role in the pathogenesis of chronic hepatitis C (HC). In the present study, we have combined immuno‐capture and reverse transcriptase‐polymerase chain reaction (RT‐PCR), and developed a quick method of high specificity for the detection of complement‐bound HCV‐CIC. We found that there were higher frequencies of HCV‐C1q CIC than that of HCV‐factor B, and there was a deviation of complement from immunoglobulin (Ig) in HCV‐CIC. These findings suggest that immuno‐capture RT‐PCR (iRT‐PCR) for the detection of HCV‐bound CIC is a valuable method for the analysis of the composition of the immune complexes, and for the understanding of host immune response and immune pathogenesis in HCV‐infected individuals.
Pharmacological Disintegration of Lipid Rafts Decreases Specific Tetramer Binding and Disrupts the CD3 Complex and CD8 Heterodimer in Human Cytotoxic T Lymphocytes
Authors: Uhlin M. , Masucci M. G. , Levitsky V.
Published: March 2003

Accumulating evidence strongly supports the role of lipid rafts in the regulation of T‐lymphocyte activation, but the organization and molecular composition of these cholesterol‐ and sphingolipid‐rich membrane microdomains in different subsets of T cells remain poorly investigated. Here, we show that pharmacological disruption of lipid rafts in human CD8+ cytotoxic T‐lymphocyte (CTL) clones disturbs the integrity of CD3 complex and CD8 heterodimer, without affecting the reactivity with T‐cell receptor (TCR)‐specific antibodies. This demonstrates that interaction with completely assembled CD3 complex is not required for the stable expression of TCR at the cell surface. The effect of raft disruption on CD3 and CD8 expression correlates with failure to bind specific tetrameric complexes by a proportion of surface TCR molecules. However, the interaction of specific tetramer with the rest of surface TCR pools appears to be unaffected, demonstrating that TCR‐signalling complexes may differ in their requirement for cholesterol to stably maintain their composition and to rearrange for efficient tetramer binding. Together with previously published data, our results support the existence of molecular and/or structural heterogeneity of lipid rafts that may play an important role in controlling distinct functional properties of T‐cell subsets.
Recent, arctic deltaic sedimentation: Olivier Islands, Mackenzie Delta, North‐west Territories, Canada
Authors: JENNER K. A. , HILL P. R.
Published: March 2003

Despite a low tidal range and relatively low wave conditions, the Mackenzie Delta is not prograding seaward but rather is undergoing transgressive shoreface erosion and drowning of distributary channel mouths. In the Olivier Islands region of the Mackenzie Delta the resultant morphology consists of a network of primary and secondary channels separated by vegetated islands. New ground is formed through channel infilling and landward‐directed bar accretion. This sedimentation is characterized by seven sedimentary facies: (1) hard, cohesive silty clay at the base of primary channels which may be related to earlier, offshore deposition; (2) ripple laminated sand beds, believed to be channel‐fill deposits; (3) ripple laminated sand and silt, interpreted as flood‐stage subaqueous bar deposits; (4) ripple laminated or wavy bedded sand, silt and clay, representing the abandonment phase of channel‐fill deposits and lateral subaqueous bar deposition from suspension settling; (5) a well sorted very fine sand bed, presumed to result from a single storm event; (6) parallel or wavy beds of rooted silt, sand and clay, interpreted as lower energy emergent bar deposits; and (7) parallel or wavy beds of rooted silt and clay, believed to represent present‐day subaerial bar aggradation. The distribution of sedimentary facies can be interpreted in terms of the morphological evolution of the study area. Initial bar deposition of facies 3 and channel deposition of facies 2 was followed by lateral and upstream bar sedimentation of facies 3 and 4 which culminated with the deposition of the storm bed of facies 5. Facies 6 and 7 signify bar stabilization and abandonment.

Patterned ground formed by thermal contraction and preserved in sediments as small, v‐shaped sand wedges provides the most direct sedimentological indicator of the arctic climate. However, winter ice and permafrost also govern the stratigraphic development of interchannel and channel‐mouth deposits. Ice cover confines flow at primary channel mouths, promoting the bypassing of sediments across the delta front during peak discharge in the spring. Permafrost minimizes consolidation subsidence and accommodation in the nearshore, further enhancing sediment bypass. Storms limit the seaward extent of bar development and promote a distinctive pattern of upstream and lateral island growth. The effects of these controls are reflected in the vertical distribution of facies in the Olivier Islands. The sedimentary succession differs markedly from that of a low‐latitude delta.
Initial motion and pivoting characteristics of sand particles in uniform and heterogeneous beds: experiments and modelling
Authors: Wallbridge  , Voulgaris  , Tomlinson  , Collins
Published: March 2003

Experiments are described in which the threshold conditions for sediment entrainment are measured for uniform and mixed sand beds beneath both steady and combined steady/oscillatory flows. Derived critical shear stresses are compared with the mixed bed entrainment model of Wiberg & Smith (1987). As predicted by the model, coarser grains within a sand mixture are entrained at lower bed shear stresses than progressively finer grains. Entrainment occurs generally at lower shear stresses than predicted by the model, especially under unidirectional flows. This may be the result of grains resting in unusually unstable positions during the experiments because the beds are ‘unworked’ at the start of the experiments.

The model of Wiberg and Smith predicts threshold conditions more accurately for the mixed beds if the bed pivoting angle is correctly defined. The pivoting angles of the beds used here are measured using a new technique designed specifically for comparison with the threshold data. The measured angles repeat the finding that the coarse grains are more mobile than the finer fractions of a mixture. The results are poorly described by the pivoting angle model presented by Wiberg & Smith (1987) and are better represented by a model of the form Φ = αDγ(Di/D50)β (after
Li & Komar, 1986), where α, γ and β are empirical constants. The threshold model is found to be more effective using the improved pivoting relationship.

The entrainment of grains is found to be easier beneath unidirectional flows than combined flows, in accordance with previous authors’ findings. A suggestion that this result is caused by a change in the erosion mechanism beneath wave flows is made. Wave boundary layers may act as an extended laminar sublayer over bed grains and reduce the erosive efficiency of the overlying current flow. The results of the experiment have implications for the natural sorting mechanisms of sediment beds being deposited in near‐threshold flows.
On the ignition of geostrophically rotating turbidity currents
Authors: Emms
Published: March 2003

Two models of a geostrophically rotating turbidity current are examined to compare predictions for ignition with the catastrophic state. Both models describe the current as a tube of sediment‐laden water traversing along and down a uniform slope. The first (four‐equation) model neglects the energy required to lift the sediment from the seabed into suspension. The second (five‐equation) model rectifies this shortcoming by introducing a turbulent kinetic energy equation and coupling the bottom stress to turbulence in the plume. These models can be used to predict the ignition, path and sediment deposition of a geostrophically rotating turbidity current. The criteria for ignition in the four‐equation model can be described by a surface in three‐dimensional phase space (for a non‐entraining current). This surface lies near the geostrophic equilibrium state. For a turbidity current occurring in the Greenland Sea, velocities above 0·053 m s–1 or volumetric concentrations of sediment above 2·7 × 10–5 lead to ignition. In general, if the tube is started pointing downslope, then ignition is more likely than if it is initially directed alongslope. However, there exists a set of initial conditions in which the current ignites if started along or downslope, but deposits if started at an intermediate angle. The five‐equation model requires a larger initial velocity (greater than 1·6 m s–1) to ignite than does the four‐equation model. Ignition is determined qualitatively by the geostrophic state and the initial normal Froude number. Solutions show a tendency to travel further alongslope during ignition, reflecting the restriction that the energy budget places on the sediment load. A qualitative difference to phase space in the five‐equation model is the existence of a region in which the tube has insufficient energy to support the sediment. Turbulence dies rapidly in this region, and so the sediment is deposited almost immediately.
Eocene cool‐water carbonate and biosiliceous sedimentation dynamics, St Vincent Basin, South Australia
Authors: James Noel P. , Bone Yvonne
Published: March 2003

Middle and Upper Eocene biogenic sediments in the Willunga Embayment along the eastern margin of the St Vincent Basin are a series of warm‐temperate limestones, marls and spiculites. The Middle Eocene Tortachilla Limestone is a thin, coarse grained, quartzose, biofragmental, bryozoan–mollusc calcarenite of stacked metre‐scale depositional cycles with hardground caps. Lithification, aragonite dissolution and the filling of moulds by sediment and cement characterize early marine‐meteoric diagenesis. Further meteoric diagenesis at the end of Tortachilla deposition resulted in dissolution, Fe‐oxide precipitation and calcite cementation. The Upper Eocene Blanche Point Formation is composed of coccolith and spiculite marl and spiculite, all locally rich in glauconite, turritellid gastropods and sponges. Decimetre‐scale units, locally capped by firmgrounds, have fossiliferous lower parts and relatively barren upper parts. Carbonate diagenesis is minor, with much aragonite still present, but early silicification is extensive, except in the spiculite, which is still opal‐A. All depositional environments are interpreted as relatively shallow water: high energy during the Middle Eocene and low energy during the Upper Eocene, reflecting the variable importance of a basin‐entrance archipelago of carbonate highs. Marls and spiculites are interpreted to have formed under an overall estuarine circulation system in a humid climate. Basinal waters, although well mixed, were turbid and rich in land‐derived nutrients, yet subphotic near the sea floor. These low‐energy, inner‐shelf biosiliceous sediments occur in coeval environments across other parts of Australia and elsewhere in the rock record, suggesting that they are a recurring element of the cool‐water, carbonate shelf depositional system. Thus, spiculites and spiculitic carbonates in the rock record need be neither deep basinal nor polar in origin. The paradox of a shallow‐water carbonate–spiculite association may be more common in geological history than generally realized and may reflect a characteristic mid‐latitude, humid climate, temperate water, palaeoenvironmental association.
The role of diagenetic carbonate concretions in the preservation of the original sedimentary record
Authors: El Albani A. , Vachard D. , Kuhnt W. , Thurow J.
Published: March 2003

The Upper Cretaceous organic rich limestones and marls of the Tarfaya basin of southwest Morocco contain numerous calcite concretions, which formed during early diagenesis. Relative textural similarities are observed both in the concretions and in the host sediments. However, the biological content of the concretions is considerably higher than in the host marls and limestones. Evidence for fossil dissolution in the host marls, and the absence of concretions in some fossil‐rich zones, suggest that the difference in fossil abundance between the concretions and host rock is a function of dissolution, rather than preferential precipitation in fossil‐rich areas. Consequently, the carbonate concretions appear to represent the ‘memory’ of the sediment and allow quantification of the original biological components and are potential tools for estimating the original biological material deposited in the soft sediments.