bluuebunny/crossref_metadata_2025 huggingface dataset:
Triggering of Target of an Antiproliferative Antibody‐1 (TAPA‐1/CD81) Up‐Regulates the Release of Tumour Necrosis Factor‐α by the EBV‐B Lymphoblastoid Cell Line JY
Authors: ALTOMONTE M. , MONTAGNER R. , PUCILLO C. , MAIO M.
Published: November 2003

Target of an antiproliferative antibody‐1 (TAPA‐1/CD81) has been shown to be non‐covalently associated to HLA‐DR antigens on the cell surface of B cells. In this study the authors report that triggering of CD81 by MoAb 5A6 or 1D6 significantly (P < 0.05) up‐regulates the release of tumour necrosis factor‐α (TNF‐α) by the Epstein–Barr virus‐positive (EBV)‐B lymphoblastoid cell line JY. The accumulation of TNF‐α in the culture medium of JY cells incubated with either anti‐CD81 MoAb was found to be dose‐dependent and similar to that obtained following crosslinking of HLA‐DR antigens with MoAb L243. The effect of the combination of anti‐CD81 and anti‐HLA‐DR MoAb on the release of TNF‐α by JY cells was not synergistic or additive. In addition, the combination of anti‐CD81 and anti‐HLA‐DR MoAb did not affect proliferation and homotypic aggregation of JY cells induced by each MoAb used alone. Both anti‐CD81 or anti‐HLA‐DR MoAb induced protein tyrosine phosphorylation. However, different cytoplasmic proteins were phosphorylated following triggering of either molecule. Taken together, the data demonstrate that CD81 and HLA‐DR antigens induce similar effector phenomena in the regulation of TNF‐α release, homotypic aggregation and inhibition of JY cell proliferation.
The Influence of Follicular Dendritic Cells on B‐Cell Proliferation Depends on the Activation of B Cells and the Mitogen Used
Authors: BOSSELOIR A. , BOUZAHZAH F. , DEFRANCE TH. , HEINEN E. , SIMAR L. J.
Published: November 2003

Follicular dendritic cells (FDC) are unique non‐lymphoid cells found only in lymph follicles. They play a part in the survival, proliferation and differentiation of B cells. To analyse the influence of FDC on B‐lymphocyte proliferation, we isolatedthem from human tonsils on albumin gradients and treated them with mitomycin C to prevent the multiplication of lymphoid cells harboured in their cytoplasmic evaginations. FDC cultured for 12–16 h remained attached to the substrate;non‐adherent cells were carefully eliminated by washing. Purified B cells cultured alone or with contaminant‐cleared FDC were maintained for 2 days in the presence or absence of various stimulants, after which tritiated thymidine uptake by these cells was measured. In the absence of activators, FDC did not induce B‐cell multiplication. B cells cultured in the presence of FDC exhibited increased 3H‐TdR uptake when activated with anti‐CD40 MoAb, anti‐immunoglobulin MoAb or transferrin, but notwhen stimulated with Staphylococcus aureus strain Cowan I (SAC) at a given concentration. In the latter case, B‐cell proliferation clearly decreased. In control cocultures where mitomycin‐C‐treated non‐adherent cells were used instead of FDC inthe presence of the different stimulants, no increase in B‐cell proliferation was observed. The results suggest that, inside the germinal centres, FDC modulation of B‐cell proliferation depends on the activation state of the B cells and on the stimulantencountered.
CD5+B Cells: Differential Capping and Modulation of IgM and CD5
Authors: JAMIN C. , LYDYARD P. M. , LE CORRE R. , YOUINOU P. Y.
Published: November 2003

CD5 is associated with the B‐cell antigen receptor (BcR) complex. As an approach to understanding its role in B‐cell function, the authors investigated the capping and modulation of CD5 and surface IgM (sIgM). Tonsillar B cells were treated withanti‐IgM or anti‐CD5 antibodies, capping examined after 1 h (by fluorescence microscopy) and modulation after 24 h (by flow cytometry). CD5 co‐capped and co‐modulated with sIgM. Of various drugs tested, only the protein tyrosine kinaseinhibitor (genistein) had any effect on capping and co‐capping. Capping of sIgM (and co‐capping of CD5) but not capping of CD5 (or co‐capping of sIgM) was inhibited by genistein. None of the other drugs affecting PKC or cytoskeletal structures (colchicine and cytochalasin D) had any effect. However, the PKC inhibitors, staurosporine and H‐7, inhibited the modulation of sIgM by anti‐IgM but not CD5 by anti‐CD5. In contrast, PKC activators, PMA and mezerein, inhibited modulation of CD5 by anti‐CD5 but notsIgM by anti‐IgM. This suggests that direct ligation of CD5 utilizes different signalling pathways compared with sIgM. It seems likely that in CD5+ B cells, interaction of CD5 with its ligand CD72 modulates signals transmitted through theBcR.
T Helper‐Independent Activation of Human CD8+ Cells: the Role of CD28 Costimulation
Authors: VAN GOOL S. W. , ZHANG YIQUN , KASRAN A. , DE BOER M. , CEUPPENS J. L.
Published: November 2003

The concept that activation of MHC class I‐restricted CD8+ cells entirely depends on help from MHC class II‐restricted CD4+ T cells has recently been supplemented with an alternative model in which CD8+ cells can directly be activated by MHC class I‐expressing professional antigen‐presenting cells (APC), which are able to deliver an accessory signal. The authors analysed the role of CD28‐mediated costimulation for T helper cell‐independent activation of purified human CD8+ T cells in two different in vitro models. Freshly isolated CD8+ cells could be activated (proliferation, IL‐2 production and cytotoxic activity) by anti‐CD3‐presenting FcγR+ mouse cells transfected with the human CD28 ligand, CD80, as the only accessory signal. On the other hand, activation of CD8+ cells by allogeneic MHC class I on EBV‐transformed B cells, which express two different CD28 ligands, CD80 and CD86, also proceeded very efficiently (proliferation, cytotoxic activity and CD25 expression), but was either not, or only partially, blocked by anti‐CD80 and anti‐CD86 MoAb or CTLA‐4Ig. This indicates that other costimulatory signals are also effective, and that CD28 triggering is not absolutely required for initial T‐cell activation. CsA and CD80/CD86‐blocking agents were synergistic in completely inhibiting activation of CD8+ cells in the MLR with allogeneic B‐cell lines. This combination also induced non‐responsiveness of CD8+ cells upon restimulation in the absence of blocking agents. Therefore, although professional APC can apparently provide multiple costimulatory signals for direct activation of CD8+ T cells, the signal derived from CD80/CD86 is unique in providing CsA‐resistance.
Co‐Stimulation‐Induced Release of Pro‐Inflammatory Cytokine Interleukin‐8 by Allergen‐Specific T Cells
Authors: SPINOZZI F. , AGEA E. , PIATTONI S. , BISTONI O. , GRIGNANI F. , BERTOTTO A.
Published: November 2003

Chemokines, which include interleukin (IL)‐8, are a family of pro‐inflammatory molecules with potent chemoattractant activity on neutrophils, as well as other cell types. IL‐8 can be recovered from many inflammatory sites. To test the hypothesis that Th2‐type allergen‐specific T cells, known to be the main cell type governing the allergic inflammation, are a source of IL‐8 and to investigate whether IL‐8 release is influenced by the nature of the in vitro mitogenic or co‐mitogenic stimulation, cypress‐specific T‐cell clones (TCC) were generated from five allergic subjects during in vitro seasonal exposure to the allergen. Purified cypress extract was produced directly from freshly collected pollen and used for in vitro stimulation of PBMC bulk cultures. After 5 days priming and a further 7 day period of IL‐2‐driven cell expansion, monoclonal antibodies to CD3, CD2 and CD28 were adopted for in vitro restimulation of allergen‐specific cell lines or, subsequently, secondary established TCC. The induction of apoptosis was detected by propidium iodide (PI) cytofluorimetric assay. Basal and co‐stimulation‐induced IL‐8 production was measured by an ELISA method. Both cypress‐specific T‐cell lines and TCC secreted appreciable amounts of IL‐8. By cross‐linking T‐cell lines or Th2 CD4+ TCC with CD3, CD2 or CD28 MoAbs, the authors observed a great stimulation‐induced IL‐8 secretion, preferentially after CD2 or combined CD2/CD28 stimulation. In addition, CD4+ clones released large amounts of IL‐8 into culture supernatants after CD2 stimulation while undergoing programmed cell death (30–40% hypodiploid DNA profile of PI‐stained cells). In contrast, CD3 crosslinking was unable to determine the release of IL‐8 or the induction of apoptosis. Taken together, these results suggest that incomplete TcR engagement by allergen may lead to the secretion of pro‐inflammatory cytokines with a contemporary induction of apoptosis in a significant number of target cells. This phenomenon may represent an additional way for local recruitment of neutrophils and basophils.
The Effect of Anti‐Oestrogens on Cytokine Production In Vitro
Authors: JÄRVINEN L. S. , PYRHÖNEN S. , KAIREMO K. J. A. , PAAVONEN T.
Published: November 2003

Oestrogens can regulate immune functions, and due to this females have more effective immune responses than males. Oestrogens and anti‐oestrogens enhance T‐cell‐dependent antibody production of B cells in vitro. The cytokine mediators which are behind oestrogen and anti‐oestrogen induced effects are not yet known. The authors studied whether anti‐oestrogens (tamoxifen and toremifene) can regulate PMA‐induced cytokine production of B‐, T‐or myeloid cell lines. Anti‐oestrogens, tamoxifen and toremifene, stimulated overall cytokine production on a B‐cell line (Ball), whereas on a T‐cell line (Molt‐4) tamoxifen stimulated IL‐1β, IL‐6 and IFN‐γ production and toremifene inhibited it. Anti‐oestrogens did not have any significant effect on cytokine production of myeloid cells.
Chagasic Patients Lack CD28 Expression on Many of Their Circulating T Lymphocytes
Authors: DUTRA W. O. , MARTINS‐FILHO O. A. , CANÇADO J. R. , PINTO‐DIAS J. C. , BRENER Z. , GAZZINELLI G. , CARVALHO J. F. , COLLEY D. G.
Published: November 2003

A balanced host‐parasite interaction during Trypanosoma cruzi infection allows for the establishment of a chronic infection that can last for many years. T cells are a major element responsible for parasite specific and non‐specific immunityduring the complex immune response of the host. However, the sub‐populations of T cells involved in the response, as well as the exact mechanisms through which those cells are activated or rendered unresponsive, are not well defined. It is known thatco‐stimulatory signals, some of which are mediated via CD28, are of critical importance in the triggering of appropriate T cell responses. In this study the authors performed double‐labelling studies to determine the frequency of expression of CD28 byCD4+ and CD8+ T lymphocytes in the peripheral blood of patients with Chagas’ disease. The results show that chagasic patients throughout the spectrum of chronic clinical forms of the infection have significantly higher meanfrequencies of CD4+CD28– and CD8+CD28– T cells, as compared with non‐chagasic individuals. Considering the importance of CD28 for T‐cell activation, the observed down‐regulation or loss of CD28during infection may indicate a possible basis for observed immunoregulatory events or distinct stages of T‐cell activation in this infection. Recent evidence from patients with HIV/AIDS indicates that CD28– cell populations are morelikely to undergo apoptosis, and increased apoptosis has been observed in experimental Chagas disease.
Perivascular T Cells Express the Pro‐Inflammatory Chemokine RANTES mRNA in Multiple Sclerosis Lesions
Authors: HVAS J. , McLEAN C. , JUSTESEN J. , KANNOURAKIS G. , STEINMAN L. , OKSENBERG J. R. , BERNARD C. C. A.
Published: November 2003

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS), characterized by accumulation of mononuclear cells. The pathogenesis of MS is complex and probably involves soluble immune mediators, particularly cytokines, and activated memory T cells, that are thought to migrate into the CNS. During lesion formation in MS, cytokines regulate cell functions, such as cell recruitment and migration. Because the chemokine RANTES play a role in both activating and recruiting leucocytes, particularly memory T cells into inflammatory sites, the authors have assessed RANTES mRNA levels at the site of lesions. Expression levels were analysed in brain samples and compared with neurological, infectious and other controls. RANTES was expressed by activated perivascular memory T cells, predominantly located at the edge of active plaques. While RANTES mRNA was detected in all 17 MS brains analysed, it was only found in six of the 14 control patients and generally at a lower expression level. In view of the regulatory and chemotactic properties of RANTES, these results imply that RANTES in MS lesions may play an important role in the activation and/or selective accumulation of memory T cells and, thereby, in the pathogenic events associated with MS.
Peptide Binding to MHC Class I is Determined by Individual Pockets in the Binding Groove
Authors: JOHANSEN T. E. , McCULLOUGH K. , CATIPOVIC B. , SU X.‐M. , AMZEL M. , SCHNECK J. P.
Published: November 2003

H‐2Kb and HLA‐A2 are MHC4 class I molecules with a similar overall structure. Important differences between these two class I molecules reside in the structure of the individual pockets in the antigenic‐peptide‐binding groove. H‐2Kb, which has a deep C pocket, binds specifically peptides with a tyrosine or a phenylalanine at position 5. In contrast, HLA‐A2 has a shallow C pocket, which cannot accommodate large side chains at position 5. Site‐directed mutagenesis was used to generate a chimera between the murine H‐2Kb and the human HLA‐A2 [H‐2Kb/HLA‐A2(C′)]. The structure of this chimera is similar to H‐2Kb except for the region around the deep C pocket, where residues at positions 9, 97 and 99 were substituted with those bulkier residues from HLA‐A2. Peptide binding between this chimera and H‐2Kb‐binding peptides [VSV (52–59), OVA (257–264), and MCMV pp89 (168–176)], revealed that the deep C pocket of H‐2Kb was crucial for high‐affinity binding. While a peptide, VSV (52–59), was found to bind with severalfold lower ‘affinity’ to H‐2Kb/HLA‐A2(C′) than to the wild‐type H‐2Kb, a VSV analogue with the tyrosine in position 5 (Tyr5) substituted with an alanine was found to bind with a similar ‘affinity’ to both MHC class I molecules. Computer‐aided modelling of the H‐2Kb/HLA‐A2(C′) complex indicates that the VSV (52–59) peptide probably binds to the chimeric MHC molecule with the peptide side chain of anchor residue Tyr5 pointing away from the groove. These results confirm a role of the individual pockets in determining peptide‐binding affinity and specificity and suggest that this may be accomplished by changes in side‐chain orientation.
α1‐Microglobulin and Bikunin in Rats with Collagen II‐Induced Arthritis: Plasma Levels and Liver mRNA Content
Authors: FALKENBERG C. , BLOM A. , FRIES E. , EKSTRÖM G. , SÄRNSTRAND B. , SALIER J.‐P. , ÅKERSTRÖM B.
Published: November 2003

The plasma proteins α1‐microglobulin (α1‐m) and bikunin are synthesized in the liver as a common precursor which is cleaved just before secretion. Half of plasma α1‐m is covalently linked to fibronectin and α1‐inhibitor‐3, and more than 95% of bikunin is part of pre‐α‐inhibitor, inter‐α‐inhibitor and related large molecules. Both α1‐m and bikunin have been shown to be involved in inflammation, but the regulation of their synthesis is not clear. The authors have measured the plasma and urinary concentrations of α1‐m and bikunin as well as their hepatic mRNA levels in rats during the development of collagen‐induced arthritis. Also, the plasma concentrations of acknowledged acute‐phase proteins were measured. The results suggested a biphasic inflammatory reaction: an early response after 1 week, represented by an elevated fibronectin level; and a late response after 3 weeks, represented by elevated α1‐acid glycoprotein and decreased albumin and α1‐inhibitor‐3 levels. The α1‐m–bikunin mRNA content in liver was slightly reduced after 1 week and elevated after 3 weeks, but the total concentrations of free and bound α1‐m and bikunin in plasma were unchanged. The free bikunin fraction as well as the fibronectin/α1‐m complex in plasma, however, were elevated after 1 week. Urinary bikunin levels were also elevated after 1 week, whereas urinary α1‐m levels remained unchanged. The results thus suggest that free bikunin in plasma is increased and excreted in the urine at an early stage during the development of collagen‐induced arthritis. Later, when the synthesis rate of α1‐m–bikunin is elevated, both proteins are most likely directed to other locations in the body.
Severe Graft‐Versus‐Host Disease in SCID Mice is Associated with a Decrease of Selective Donor Cell TCR Vβ Specificities and Increased Expression of IFN‐γ and IL‐4
Authors: SCHNEIDER M. K. J. , EKHOLM F. , GRÖNVIK K.‐O.
Published: November 2003

Differences in T‐cell selection and severity of graft‐versus‐host (GVH) disease were observed in immunodeficient C.B‐17 SCID (SCID) mice after injection of allogeneic T lymphocytes from CBA/J or C57Bl/6 (B6) mice. Infiltrating donor cells were analysed in bone marrow (BM), liver and spleen of newborn recipients and 5 days post‐engraftment the number of B6 cells significantly exceeded that of CBA/J cells in these organs. At that time, cells in BM of B6 and CBA/J injected recipients were augmented in intracellular IL‐4, IL‐10, and TNF‐α, whereas only cells in B6 treated BM were increased in IFN‐γ, and both treated groups of mice had up‐regulated endogenous MHC class I and class II expression in the three organs. Already on day 5, and more pronounced day 10, B6 treated SCIDs had a relative decrease of four different TCR‐Vβ specificities among donor cells, whereas CBA/J injected mice had an abnormal expansion of Vβ14+ donor T cells 10 days post injection. At the same time, the total cell contents of BM and spleen of B6 injected mice were substantially decreased, and this was paralleled by signs of severe GVHD; whereas SCIDs treated with CBA/J exhibited much milder symptoms. Moreover, adult SCID mice injected with Vβ2, 4, 8 and 14 depleted B6 T cells showed an increased percentage of infiltrating donor cells and an enhanced decrease in BM cell content compared to SCIDs treated with total B6 T cell repertoire. In vitro, the Vβ2, 4, 8 and 14 depleted population was more responsive to SCID spleen stimulators. Thus, a disturbed immunoregulation among donor T cells, caused by multiple changes in the TCR repertoire, may be responsible for inducing the severe GVHD.
Surface Properties of Antigen–Antibody Complexes
Authors: WINGREN C. , HANSSON U.‐B.
Published: November 2003

In this paper, the authors show that liquid–liquid partition chromatography in an aqueous two‐phase system offers unique possibilities of comparing the overall surface properties of intact antibodies in solution before and after binding of antigen. The authors demonstrate that the surface properties of antigen–antibody complexes are dependent on the variable regions of the antibodies, the nature of the antigen and/or possible conformational changes induced by antigen binding. Thus, each antigen–IgG antibody pair formed one type of complex with respect to the exposed dominant surface. The antigen‐binding sites of IgG antibodies were exposed and dominant even after binding of hapten or hapten‐carrier. In contrast, the antibody‐combining sites were concealed upon protein binding and the exposed surfaces of the protein–antibody complexes were related mainly to those of the antigen. IgA1, IgA2, IgE and IgM formed, in comparison to the IgG, hapten–antibody complexes which exhibited surface properties that could be related to both the antigen‐binding sites and Fc parts of the antibodies. Moreover, the results indicated that antigen‐induced conformational changes occurred in either IgA1, IgA2, IgE, or IgM, but not in IgG1, ‐2, ‐3 and ‐4, making the surfaces of their heavy chain constant regions more similar.
Electrophoretic Polymorphism of a Hamster Pentraxin, Female Protein (Amyloid P Component)
Authors: COE J. E. , ROSS M. J.
Published: November 2003

Serum amyloid P protein (SAP) is a ubiquitous vertebrate protein distinguished by its conservative evolution and paucity of polymorphic forms. The SAP homologue in the Syrian hamster (Mesocricetus auratus), called Female Protein [FP(SAP)] is unique because its synthesis is controlled by sex hormones. These observations were limited to the commercially available standard Syrian hamsters that are descendants of three littermates captured in Syria in 1930. The authors examined FP(SAP) expression in nine inbred lines of Syrian hamsters that were derived from 12 wild hamsters captured in 1971. In general, regulation of FP(SAP) was similar in the new wild hamster strains, although a novel electrophoretically slower FP(SAP) was found in three of the strains. The slow FP(SAP) was not distinguished by size, antigenicity, binding capacity, or regulation. The electrophoretic difference was still apparent after deglycosylation. Hybrid offspring coexpressed both fast and slow FP monomers and formed a unique hybrid pentamer that had a new mobility between the fast and slow parent FP(SAP). The origin of this unusual polymorphism could be related to the amyloidogenesis associated with expression of FP(SAP) in the standard Syrian hamster.
Mannan‐Binding Lectin in the Sub‐Saharan HIV and Tuberculosis Epidemics
Authors: GARRED P. , RICHTER C. , ANDERSEN Å. B. , MADSEN H. O. , MTONI I. , SVEJGAARD A. , SHAO J.
Published: November 2003

Inherited deficiency of mannan‐binding lectin (MBL) has been shown to predispose to infections. Conversely, it has also been suggested that MBL might facilitate the uptake of certain intracellular microbes. The aim of this study was to investigate whether MBL plays a role in the HIV and tuberculosis epidemics in Africa. Thus, the authors determined the MBL serum concentration in 173 HIV infected patients (150 with concomitant tuberculosis), 94 patients with tuberculosis without being HIV infected, and 113 controls from Tanzania. The frequency of MBL deficiency was significantly increased in HIV infected patients compared with controls (12.1% and 3.5%, respectively). The frequency of patients deficient of MBL did not differ between controls and HIV negative patients with tuberculosis. However, HIV negative patients with tuberculosis had significantly higher MBL levels than both controls and HIV infected patients with or without tuberculosis. These results indicate that low levels of MBL are associated with increased risk of sexually transmitted HIV infection in Africans. By contrast, high levels of MBL may be involved in the pathogenesis of tuberculosis in immunocompetent individuals.
T Cell Subsets and T Cell Function in Cartilage‐Hair Hypoplasia
Authors: KOOIJMAN R. , VAN DER BURGT C. J. A. M. , WEEMAES C. M. R. , HARALDSSON A. , SCHOLTENS E. J. , ZEGERS B. J. M.
Published: November 2003

Cartilage hair hypoplasia is a rare autosomal recessive form of short‐limbed dwarfism associated with a cellular immunodeficiency. In eight patients, the authors studied the presence of T cell subsets and in vitro T cell function in order to address the basis for the immunological disorder. Both the proliferative response to phytohaemagglutinin (PHA) and the PHA‐induced IL2 production were 60% lower compared with controls (P  =  0.007 and 0.005, respectively). The impaired proliferative response could not be restored by addition of IL‐2. This result is in accordance with a decrease in the percentage of activated T cells expressing the p 55 subunit of the IL‐2 receptor complex (CD25). The results define more precisely that T cells from cartilage hair hypoplasia patients are defective in the transition from the G0 to the G1 phase of the cell cycle. Furthermore, the data demonstrate that several CHH patients show a reduced proportion of CD45RA+‘naive’ T cells. However, the in vitro impairment of T cell function cannot solely be explained by imbalance between ‘naive’ and ‘memory’ T cells. Although CHH patients with a history of recurrent respiratory tract infections showed the most aberrant in vitro immune parameters, a clear relationship between clinical data and in vitro parameters could not be established for the whole patient group.
Neonatal Tolerance to Alloantigens is Induced by Enriched Antigen‐Presenting Cells
Authors: MODIGLIANI Y. , BURLEN‐DEFRANOUX O. , BANDEIRA A. , COUTINHO A.
Published: November 2003

Spleen and bone marrow cells from normal or Rag‐1‐deficient donors are equally competent in their ability to induce neonatal transplantation tolerance in semi‐allogeneic hosts, and the latter are also capable of tolerizing fully allogeneic recipients. Both types of donor cells resulted in comparable levels of haemopoietic chimerism in tolerant animals. Lymphoid hyperactivity, however, was absent in animals tolerized with Rag‐1‐deficient cells. The authors conclude that neonatal tolerance induced with haemopoietic cells requires no donor lymphocytes, and is thus not the result of deficient antigen presentation. Furthermore, the state of tolerance can be dissociated from the lymphoid hyperactivity that requires donor lymphocytes and is regularly scored in conventionally tolerized animals.
Flow Cytometric Study of Blood Leucocytes in Clinical Forms of Human Schistosomiasis
Authors: MARTINS‐FILHO O. A. , DUTRA W. O. , FREEMAN G. L. , SILVEIRA A. M. S. , RABELLO A. , COLLEY D. G. , PRATA A. , GAZZINELLI G. , CORREA‐OLIVEIRA R. , CARVALHO‐PARRA J.
Published: November 2003

The aim of this study was to examine three distinct groups of schistosomiasis patients and to determine whether cell phenotype profiles could be correlated with the different clinical forms of the disease. The data obtained indicate that Schistosoma mansoni infected patients have a lower percentage of CD3+ T cells than do non‐infected individuals. Interestingly, infected patients presented more than twice the mean percentage of circulating activated T cells (CD3+HLA‐DR+) when compared to the control group. Examination of T lymphocyte subpopulations showed that patients with the severe hepatosplenic form (HS) of the disease had lower levels of both CD8High+ and CD8Low+ cells when compared to the other groups of patients. All infected individuals had a higher percentage of circulating B cells, with an increase in the CD5+ B cell population that was more evident in the HS group. The data presented here are evidence to support a relationship between the hepatosplenic form of the disease, a decrease on the CD8+ cell population and an elevation on CD5+B cells.
Production of Interferon‐α/β by Murine Dendritic Cell Lines Stimulated by Virus and Bacteria
Authors: ELORANTA M.‐L. , SANDBERG K. , RICCIARDI‐CASTAGNOLI P. , LINDAHL M. , ALM G. V.
Published: November 2003

The interferon‐α and ‐β (IFN‐α/β) producing ability of the two murine dendritic cell (DC) lines D2SC/1 and FSDC was studied. The D2SC/1 cells produced IFN‐α and ‐β when stimulated by herpes simplex virus (HSV), Sendai virus (SV) or by the bacteria Escherichia coli or Staphylococcus aureus Cowan I. Precultivating (priming) D2SC/1 cells with recombinant IFN‐β or a combination of IFN‐β and granulocyte–macrophage colony‐stimulating factor increased production of IFN‐α/β induced by HSV or the bacteria, but not by SV. Also, the kinetics of IFN‐α/β responses were different for SV compared to HSV and the bacteria, suggesting different induction mechanisms. The FSDC cells differed from the D2SC/1 cells mainly in that predominantly IFN‐β was produced, that little or no IFN‐α/β production was induced by the bacteria, and that the IFN‐α/β responses were most efficiently primed by IFN‐γ. Priming the DC lines with tumour necrosis factor‐α, interleukin‐10 (IL‐10) or IL‐4 did not affect the IFN‐α/β response induced by HSV. The results show that the two DC lines provide a convenient tool to study the induction and control of the IFN‐α/β response, as well as the immunoregulatory role of IFN‐α/β produced by DC.
A Comparative Study of Normal B Cells and the EBV‐Positive Burkitt's Lymphoma Cell Line, Raji, as Activators of the Complement System
Authors: MARQUART H. V. , OLESEN E. H. , JOHNSON A. A. , DAMGAARD G. , LESLIE R. G. Q.
Published: November 2003

Contradictory reports regarding the ability of complement receptor type 2 (CR2,CD21) on normal B cells to activate complement (C′) via the alternative pathway (AP), prompted us to compare the performance of human peripheral blood B cells and the Epstein–Barr virus‐positive Burkitt's lymphoma cell line, Raji (a well characterized AP activator) by using flow cytometry. Measured in terms of the membrane deposition of C3 fragments per cell, Raji cells were significantly (6‐ to 26‐fold) more effective as complement activators than were normal B cells. Raji cells were also found to express approximately four to five times as many CR2 as normal B cells. In addition, they distinguished themselves by displaying a greater Ca2+‐dependent activation, with pooled normal human sera (NHS) as the complement source, and by degrading unprotected C3b fragments from iC3b to C3dg/C3d at a significantly lower rate than the B cells. The Ca2+ dependency of Raji cell activation was found to be partially a result of classical pathway (CP) triggering by specific antibodies in the NHS, although other triggering mechanisms may also be involved. If the influence of these variations between Raji cells and normal B cells was excluded, by relating deposition of anti‐C3d‐reactive fragments, during AP activation, to the number of CR2 expressed, the difference in performance between the two cell types was found to be insignificant.
A Preserved Native Kidney Alters Acute Renal Allograft Rejection in the Rat
Authors: GRAU V. , HERBST B. , STEINIGER B.
Published: November 2003

In this study the effect of a native recipient kidney on acute rat renal allograft rejection is analysed. The authors performed a sequential daily analysis of allograft morphology and infiltration by macrophages and T cells in the presence and the absence of a recipient kidney. Several differences among both experimental groups were observed. Infiltrating macrophages and T cells in the allograft interstitium were more numerous in the presence than in the absence of a recipient kidney. The ratio of macrophages to T cells was 2:1 in the presence and 1:1 in the absence of a recipient kidney. Interstitial allograft infiltration started 1 day earlier in the presence of a contralateral kidney than in its absence. Graft necrosis occurred on day 6 and was complete in the presence of a native kidney. After total nephrectomy a patchy pattern of necrotic and viable tubules was observed from day 5 until the death of the animal. The diameter of monocytes in graft vessels increased only moderately in the presence of a recipient kidney but duplicated in its absence. The authors propose that in experimental renal transplantation contralateral nephrectomy should be performed according to a standardized schedule.
Evidence that the Receptor for Soluble CD14:LPS Complexes may not be the Putative Signal‐Transducing Molecule Associated with Membrane‐Bound CD14
Authors: HAZIOT A. , KATZ I. , RONG G. W. , LIN X. Y. , SILVER J. , GOYERT S. M.
Published: November 2003

Membrane‐bound CD14 acts as a receptor for lipopolysaccharide (LPS) on monocytes/macrophages and neutrophils. Studies have suggested that the activation of monocytes/macrophages by the binding of LPS to membrane‐bound CD14 may require the association of a signal‐transducing molecule with membrane‐bound CD14. The observation that non‐CD14 expressing cells, such as endothelial cells, can nevertheless be activated by a complex of LPS and a soluble form of CD14 (sCD14) suggests that the receptor for this complex may be identical to the signal transducing molecule associated with membrane‐bound CD14. The studies described show that two CD14‐specific MoAb are able to block the LPS‐induced activation of endothelial cells but do not affect the response of monocytes to LPS. This suggests that the interaction of the sCD14:LPS complex with endothelial cells is distinct from the interaction of membrane‐bound CD14 with its putative signal‐transducing molecule.
The αβ T Cell Receptor Clustering Upon Superantigen/MHC Recognition
Authors: Mazda O. , SATOH E. , IMANISHI J.
Published: November 2003

Antigen recognition by T cells is the key event for the antigen specific immune responses to be triggered. This recognition is initiated by the binding of the T cell receptor (TCR) to antigen peptide/major histocompatibility complex (MHC) on the surface of the antigen presenting cells. TCR on most of the T cells is a heterodimer composed of α and β chains which are associated with CD3 γδε as well as ζ chains, the signal transmission molecules. The dynamics of this TCR complex upon antigen/MHC recognition, however, has not been well understood. In this paper the authors analyse the configuration of TCR complex on T cells from a TCR β chain gene transgenic mouse (TGM) strain. Unlike many other TGM strains reported, a considerable proportion of T cells from this TGM expresses both transgene‐encoded (Vβ3) and endogenous TCR β chains on their surface. By immunoprecipitation and immunoblotting analysis of T cells stimulated with a superantigen, staphylococcal enterotoxin B (SEB), the authors found that Vβ3 was coprecipitated with Vβ8, demonstrating the clustering of TCR αβ upon superantigen/MHC recognition.
Suppression of Delayed‐Type Contact Sensitivity in the Murine Oral Mucosa by Prior Intragastric Administration of Hapten
Authors: AHLFORS E. , CZERKINSKY C.
Published: November 2003

The effect of intragastric administration of antigen on the development of a mucosal cell‐mediated immune response has been examined in a mouse model. Feeding mice with picryl sulfonic acid (PSA) abrogated development of buccal delayed‐type contact hypersensitivity (CS) responses upon buccal challenge with picryl chloride (PCl) in animals that had previously been sensitized in the oral mucosa. In contrast, such feeding had no effect on buccal CS reactivity in animals similarly challenged but sensitized at skin sites. Conversely, gastric administration of PSA suppressed PCl‐induced skin CS reactivity in skin‐sensitized animals but had no effect on skin CS reactivity in buccally sensitized mice. Enterically induced suppression of buccal mucosa CS reactivity was associated with marked reductions in the numbers of infiltrating CD11b+ macrophages and CD4+ cells, and a virtual disappearence of CD8+ cells in buccal tissue specimens examined 24 h after local challenge. Thus, depending on the initial site of immune sensitization, oral antigens may also suppress mucosal T cell reactivity.
Regulation of Extrahepatic Apolipoprotein Serum Amyloid A (ApoSAA) Gene Expression by Interleukin‐1α Alone: Synthesis and Secretion of ApoSAA by Cultured Aortic Smooth Muscle Cells
Authors: KUMON Y. , SIPE J. D. , BRINCKERHOFF C. E. , SCHREIBER B. M.
Published: November 2003

Serum amyloid A apolipoproteins (apoSAA) appear to compromise the ability of high density lipoprotein to protect against atherosclerosis and it is of interest to determine whether aortic smooth muscle cells can contribute to local pools of apoSAA in the presence of cytokines that are known to stimulate acute phase apoSAA (A‐apoSAA) synthesis in the liver. In this study, the regulation of A‐apoSAA synthesis was monitored in cultured neonatal rabbit aortic smooth muscle cells. Constitutive apoSAA3 gene expression was minimal, and only detectable by amplification of the mRNA by reverse transcriptase–polymerase chain reaction. ApoSAA3 gene expression and protein synthesis were stimulated by IL‐1α; as little as 0.01ng/ml of IL‐1α stimulated an increase in steady state levels of apoSAA3 mRNA. Interestingly, IL‐6 (which is required in addition to IL‐1α for the optimal synthesis of A‐apoSAA by human hepatoma cells) had little if any effect on apoSAA3 synthesis by the smooth muscle cells. In a time course, it was shown that the stimulation of apoSAA3 mRNA levels was apparent by 1–2h after the addition of cytokine, and that levels remained elevated in the presence of the cytokine for at least 48h. Immunoprecipitation using an antiserum directed against apoSAA3 revealed that IL‐1α stimulated the synthesis and secretion of apoSAA3 protein in a manner that was consistent with apoSAA3 mRNA expression. The implications of these findings in atherogenesis are discussed.
Expression of the Human Immunoglobulin Heavy Chain VH6 Gene Element by Fetal B Lymphocytes
Authors: RAAPHORST F. M. , LANGLOIS VAN DEN BERGH R. , WAAIJER J. L. M. , VOSSEN J. M. , VAN TOL M. J. D.
Published: November 2003

Fetal B lymphocytes in mice and humans use a limited number of the available VH gene segments. Mouse fetal B cells primarily utilize 3′ VH elements, suggesting that the localization of these elements determines their rearrangement frequency. The previously reported non‐random usage of human VH genes has been more difficult to explain. In this study the authors analysed the expression of the most proximal 3′ human VH element (VH6) using a monoclonal antibody (JE‐6). VH6 expression was assessed in various B cell differentiation stages from fetal liver, bone marrow and spleen at 12–20 weeks of gestation. The authors demonstrate that the level of VH6 expression does not exceed a stochastic usage frequency. This suggests that the localization of VH6 does not significantly promote its expression during human fetal life, and that other factors must affect the usage of VH genes during human fetal development.
Amplification of T‐Cell and Antibody Responses in DNA‐Based Immunization with HIV‐1 Nef by Co‐Injection with a GM‐CSF Expression Vector
Authors: SVANHOLM C. , LÖWENADLER B. , WIGZELL H.
Published: November 2003

Intradermal inoculation of mice with naked plasmid DNA encoding the regulatory HIV‐1 Nef protein was shown to induce Nef‐specific T and B cell responses. Co‐inoculation with an expression vector encoding murine granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), a cytokine known to facilitate the induction of primary immune responses, resulted in a markedly enhanced response to Nef. This was manifested both as an increase in Nef‐specific T cell responses and antibody levels. DNA immunization with the Nef and GM‐CSF vectors induced primarily a Th1 response as judged by the raised levels of both IFN‐γ and IL‐2 from re‐stimulated T cells. The immunostimulatory activity of GM‐CSF DNA was locally restricted and was observed only if both plasmid vectors were injected at the same site.
L‐Selectin Expression on the Surface of Peripheral Blood Leucocytes from Rheumatoid Arthritis Patients is Linked to Disease Activity
Authors: BOND A. , HAY F. C.
Published: November 2003

Recruitment of mononuclear cells from the circulation to sites of inflammation relies on migration across vessel endothelium. T and B cells, macrophages and neutrophils infiltrate synovial tissue of rheumatoid arthritis (RA) patients. The authors have analysed the numbers of circulating CD3+, CD19+ lymphocytes, monocytes, and granulocytes expressing adhesion molecules (L‐selectin, CD44 and CD11a), together with levels of expression in RA patients compared to healthy individuals. Numbers of leucocytes expressing the adhesion molecules detected were similar in RA and control groups. Lower levels of expression of L‐selectin on all cells were found in RA patients compared to controls. Expression of L‐selectin on T and B cells was found to correlate with disease activity in RA. The authors have observed a characteristic pattern of adhesion molecule expression in RA patients, particularly when analysing the relationships between cells. The close regulation of these molecules between RA patients and healthy individuals is discussed.
Regional Phenotypic Specialization of Intraepithelial Lymphocytes in the Rat Intestine Does Not Depend on Microbial Colonization
Authors: HELGELAND L. , VAAGE J. T. , ROLSTAD B. , HALSTENSEN T. S. , MIDTVEDT T. , BRANDTZAEG P.
Published: November 2003

Recent studies in mice and humans have provided evidence for regional specialization of gut intraepithelial lymphocytes (IEL). Here the authors report striking regional variability in the composition of IEL in rat small and large intestine. Two‐colour immunofluorescence in situ analysis showed that the distribution of the CD3+ and CD3− IEL subpopulations varied, the proportion of T cells (CD3+) being higher in the ileum than in the jejunum and smallest in the colon. These differences were explained by variable numbers of the T‐cell receptor (TCR)α/β+ (both CD8+ and CD4+) but not the TCRγ/δ+ subset. Moreover, the various IEL subpopulations showed distinct intraepithelial distribution patterns with CD4+ and CD8αβ+ T cells situated near the lamina propria, while CD3− IEL were located preferentially towards the adluminal part of the epithelium. Regional phenotypic variation did not depend on intestinal colonization because analogous results were obtained in germ‐free rats. Conventionalization nevertheless caused a marked relative increase of small intestinal TCRα/β+ but not TCRγ/δ+ IEL. This increase was more sustained in the jejunum than ileum and eventually reduced the phenotypic IEL differences between the two sites. By contrast, microbial colonization of the colon induced only a transient increase of intraepithelial TCRα/β+ cells with no permanent phenotypic alterations. Both CD3+ and CD3− IEL contained subpopulations that expressed NKR‐P1 independent of intestinal colonization. These results demonstrate phenotypic specialization of IEL at different levels of the gut and suggest that the indigenous flora is not essential to this end.
Murine Thymic Nurse Cells Express ICAM‐1 on Caveolar and Vacuolar Membranes
Authors: CORDES U. , PEDERSEN M. , BASTHOLM L. , NIELSEN M. , WERDELIN O.
Published: November 2003

The thymic nurse cell is a unique type of epithelial cell in the thymic cortex. It is in intimate contact with the developing thymocytes by harbouring up to 200 thymocytes in distinct vacuoles, called caveoles. This investigation is concerned with the nurse cell expression of the intercellular adhesion molecule ICAM‐1, the ligand for thymocyte LFA‐1. Nurse cells from young Balb/c mice were isolated in a density gradient. ICAM‐1 expression was studied by using two different immunotechniques: alkaline phosphatase labelled cryosections, and immunogold electron microscopy. The specific antibody was a monoclonal rat anti‐mouse ICAM‐1. Immunostaining of cryosections demonstrated that ICAM‐1 is expressed on the surface membrane and in the internal caveolar membranes of thymic nurse cells. Electron microscopy of immunogold labelled sections revealed ICAM‐1 on the surface membrane of thymic nurse cells and on the membranes of the caveoles, the small cytoplasmic vesicles, as well as on the Golgi apparatus.
Interferon‐γ Enhancement of E‐Selectin Expression on Endothelial Cells is Inhibited by Monensin
Authors: STRINDHALL J. , LUNDBLAD A. , PÅHLSSON P.
Published: November 2003

The expression of E‐selectin reaches a maximum 4–6 h after stimulation of human umbilical vein endothelial cells (HUVEC) in vitro with tumour necrosis factor‐α (TNF‐α) and then declines to basal level within 24 h. If interferon‐γ (IFN‐γ) is added to the cell culture medium together with TNF‐α the surface expression of E‐selectin is augmented and prolonged in a synergistic way. The aim of the present study was to investigate if altered protein glycosylation could explain the IFN‐γ induced persistent surface expression of E‐selectin. SDS–PAGE analysis of HUVEC glycoproteins, metabolically radiolabelled in the carbohydrate portion, indicated that addition of IFN‐γ produced an altered protein glycosylation. Lectin blot analysis using the Sambucus nigra agglutinin lectin also indicated differences in protein glycosylation when HUVEC were incubated with IFN‐γ/TNF‐α compared to TNF‐α alone. The kinetics of surface expression of E‐selectin were measured using a cell ELISA assay. When HUVEC were incubated with monensin, a potent inhibitor of late Golgi function, together with both TNF‐α and IFN‐γ, the additive effect of IFN‐γ on E‐selectin expression was almost abolished. Since monensin is known to affect glycosylation processing, this experiment suggested that the IFN‐γ induced change in protein glycosylation might induce the prolonged surface expression of E‐selectin. However, when HUVEC were cultured with IFN‐γ/TNF‐α in the presence of several different inhibitors of N‐glycosylation processing, no significant effect of E‐selectin expression was observed. Regulation of adhesion molecule expression after activation of endothelial cells is likely to play a pivotal role for the inflammatory response. Further studies are needed to understand the mechanisms underlying this regulation.
Cytokine Regulation of Human Immune Response to Schistosoma mansoni: Analysis of the Role of IL‐4, IL‐5 and IL‐10 on Peripheral Blood Mononuclear Cell Responses
Authors: MALAQUIAS L. C. C. , FALCÃO P. L. , SILVEIRA A. M. S. , GAZZINELLI G. , PRATA A. , COFFMAN R. L. , PIZZIOLO V. , SOUZA C. P. , COLLEY D. G. , CORREA‐OLIVEIRA R.
Published: November 2003

The role of cytokines on the in vitro proliferative response of peripheral blood mononuclear cells (PBMC) from Schistosoma mansoni infected patients to soluble egg (SEA) and adult worm antigens (SWAP) were evaluated. The results obtained demonstrated that the proliferative response of PBMC from chronic intestinal (INT) patients to SEA and SWAP is increased by the blockage of IL‐10 with specific monoclonal antibodies (MAb). The effects of these antibodies were readily reversed by the addition of recombinant IL‐10. In contrast, no effect was observed on the PBMC response of acute and hepatosplenic patients (HS) in the presence of anti‐IL‐10. Anti‐IL‐4 antibodies decreased the PBMC response of the intestinal (INT) and HS individuals to SEA and SWAP, and the PBMC response of acute patients to SEA but not to SWAP. Addition of anti‐IL‐5 MAb did not decrease the PBMC response of acute patients to SEA or SWAP. These results suggested that IL‐10 has an important role in the modulation of the immune response in chronic asymptomatic patients and that this cytokine may be an important factor in controlling morbidity.
Mannuronan Enhances Survival of Lethally Irradiated Mice and Stimulates Murine Haematopoiesis In Vitro
Authors: HALAAS Ø. , OLSEN W. M. , VEIBY O. P. , LØVHAUG D. , SKJÅK‐BRÆK G. , VIK R. , ESPEVIK T.
Published: November 2003

Mannuronan (poly‐β‐(1→4)‐d‐mannuronate or poly‐M), produced by Pseudomonas aeruginosa as a mucoid exopolysaccharide, has previously been shown to exhibit immunostimulating activity. The authors investigated the in vivo and in vitro effects of mannuronan on murine haematopoiesis. In vivo, prophylactic (−24 h, intraperitoneal) administration of mannuronan enhanced survival of lethally irradiated mice from zero day 40 survivors (NaCl) to 20, 80 and 70% survival at 0.5, 1 and 2 mg/kg bw mannuronan, respectively. In vitro, primary stromal cultures stimulated with mannuronan produced high levels of interleukin(IL)‐1, IL‐6 and colony stimulating activity. Mannuronan alone did not have any colony stimulating activity on GM‐CFC, BFU‐E, Mix‐CFC or HPP‐CFC progenitors in clonogenic assays, but acted synergistically with suboptimal amounts of growth factors on GM‐CFC, Mix‐CFC and HPP‐CFC colony formation. Limiting dilution analysis showed that 1 of 423 bone marrow cells formed colonies in response to suboptimal GM‐CSF plus mannuronan compared to 1 of 592 for suboptimal GM‐CSF alone. The primitive Lin−Sca‐1+ haematopoietic progenitors showed increased day 10 colony size in the presence of mannuronan in single cell assays. These stimulating effects of mannuronan on haematopoiesis may prove to have clinical importance.