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P Vandenberghe

Publications and source records attributed to P Vandenberghe.

69 records · Page 4Linked to original sources
PubMed1995

Comparative study of peripheral blood progenitor cell collection in patients with multiple myeloma after single-dose cyclophosphamide combined with rhGM-CSF or rhG-CSF.

Patients suffering from high-risk multiple myeloma (MM) were randomized to receive single high-dose cyclophosphamide followed by either rhGM-CSF or rhG-CSF in order to harvest circulating peripheral blood progenitor cells. The safety of the procedure, the mobilization kinetics, the relative efficacy of rhGM-CSF and rhG-CSF to mobilize progenitor cells and their relative toxicity were studied. Special attention was paid to the antigenic profile of CD34+ progenitor cells. Group I patients (n = 11) were treated with cyclophosphamide 4 g/m2 i.v. followed by rhGM-CSF at 10 micrograms/kg/d by subcutaneous administration. Group II (n = 11) patients received rhG-CSF s.c. at 10 micrograms/kg/d after the same dose cyclophosphamide. Both mobilization regimens appeared to be equally effective. No significant differences in absolute numbers of circulating progenitors, determined by CD34 expression or in yields of MNC, CFU-GM, BFU-E and CD34 subsets were observed. rhGM-CSF administration resulted however in delayed haemopoietic recovery and an increased complication rate. We conclude that rhG-CSF may be preferred because of its markedly lower toxicity and lower in-hospital costs.

Adult↗
PubMed1995

Detection of P-glycoprotein with a rapid flow cytometric functional assay using Fluo-3: evaluation of sensitivity, specificity and feasibility in multiparametric analysis.

The specificity and sensitivity of a flow cytometric assay simultaneously measuring expression and transport function of the multidrug resistance associated P-glycoprotein (Pgp) was evaluated. The monoclonal antibody (mAb), MRK16 was used to detect phenotypic Pgp expression while Fluo-3-AM was used as a fluorescent substrate in a Pgp functional transport assay. The specificity of the functional assay was examined in two vinblastine selected human leukemic cell lines (K562/VLB2.5 and CCRF-CEM/VLB50) with acquired Pgp overexpression. Downmodulation of Pgp function in these cell lines could be demonstrated with different substances (verapamil, vinblastine, trifluoperazine, cyclosporin A, progesterone and quinidine) and was proven to be consistently higher in the vinblastine selected cells than in their non-selected drug sensitive counterparts. Unexpectedly, modulator activity was also observed in drug sensitive K562 and CCRF-CEM cell lines despite the inability to detect Pgp in those cells by MRK16 flow cytometrically. Low level expression of the MDR1 gene encoding Pgp in sensitive K562 cells was however demonstrated with a sensitive RT-PCR procedure. The small effect of Pgp modulators in non-drug selected cells could therefore be attributed to low level basal expression of Pgp and illustrates the sensitivity of the functional assay. Also, the effect of various Pgp modulators on Pgp function was more pronounced in a subpopulation of Pgp expressing lymphocytes than in lymphocytes which did not express Pgp. Finally, a correlation was found between discrete variations in Pgp expression and Pgp function of CD4+ lymphocytes, underscoring the feasibility of the functional assay in a triple parametric procedure. The triple parametric assay holds promise to detect Pgp expression and function in clinical samples containing mixtures of malignant and non-malignant cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

The B7/BB1 antigen is expressed by Reed-Sternberg cells of Hodgkin's disease and contributes to the stimulating capacity of Hodgkin's disease-derived cell lines.

The B7/BB1 molecule has recently been found to be expressed on professional antigen-presenting cells and to be the natural ligand for CD28 and CTLA-4 on T cells. On binding of B7/BB1, CD28 transduces a signal that synergizes with triggering of the T-cell antigen receptor, resulting in enhanced cytokine secretion. In view of the data supporting an antigen-presenting function of Reed-Sternberg cells, we evaluated the expression of B7/BB1 in lymph nodes affected by Hodgkin's disease. B7/BB1 was found to be strongly expressed by the Reed-Sternberg cells in all 47 cases of Hodgkin's disease studied. Moreover, Reed-Sternberg cells were frequently surrounded by CD28-expressing T cells. Evidence for a functional role of B7/BB1 on Reed-Sternberg cells was obtained by our findings that T-cell proliferation and interleukin-2 (IL-2) production in the primary allogenic mixed lymphocyte reaction (MLR), using the B7/BB1-expressing Hodgkin's disease-derived cell lines L428 and KM-H2 as stimulators, could be partially blocked by adding anti-B7 monoclonal antibody. B7/BB1 expression was also evaluated in a group of non-Hodgkin's lymphomas (n = 46). Whereas B7/BB1 was not expressed by the neoplastic cells of most non-Hodgkin's lymphomas, including T-cell-rich B-cell lymphoma (n = 11), it was present on the neoplastic cells of anaplastic large-cell lymphoma (Ki-1 lymphoma) (n = 5) and follicular lymphoma (n = 4). Our data provide further evidence for an accessory cell function of Reed-Sternberg cells. The accessory cell function of Reed-Sternberg cells might lead to pronounced T-cell activation in vivo, which might contribute to the Hodgkin's syndrome. In addition, our study indicates that B7/BB1 may be a useful marker for differentiating Hodgkin's disease from morphologically similar conditions such as T-cell-rich B-cell lymphoma.

Animals↗
PubMed1993

Simultaneous ligation of CD5 and CD28 on resting T lymphocytes induces T cell activation in the absence of T cell receptor/CD3 occupancy.

The T cell surface molecules CD5 and CD28 have been shown to be receptors for accessory signals in T cell activation. We here demonstrate that in the absence of any other activating stimulus, simultaneous ligation of CD5 and CD28 by mAb induces polyclonal T cell activation. Immobilization of the anti-CD28 and anti-CD5 mAb was an essential requirement for T cell stimulation. This was done either through coating of the culture plates with goat anti-mouse Ig, or by coculture with mitomycin C-treated Fc gamma R-bearing P815 mouse mastocytoma cells. Most importantly, T cells could also be stimulated with B7, the natural ligand of CD28, and anti-CD5 presented on irradiated 3T6 mouse fibroblasts co-transfected with human Fc gamma RII and with B7. Neither immobilized mAb 9.3 (anti-CD28) nor any of four different anti-CD5 mAb were mitogenic as a sole stimulus. Immobilized mAb identifying CD4, CD7, or LFA-1 were not co-mitogenic with either mAb 9.3 or one of the anti-CD5 mAb. The T cell proliferation induced by cross-linking of CD5 and CD28 is IL-2-dependent, as was demonstrated by the cell-surface expression of the p55 chain of the IL-2R, the production of IL-2, and inhibition of the proliferative response by the anti-IL-2R mAb anti-Tac. CD5/CD28 ligation induced production of TNF-alpha, but not of IL-4, and did not induce modulation of the TCR/CD3 complex. Expression of IL-2R (p55) and of CD69 preferentially occurred on CD29-low naive cells, and indicated that about 50% of the cultured cells were activated. Cell proliferation was not increased by adding monocytes to the cultures and it was inhibited by PKC inhibitors (H7 and staurosporine) and by cyclosporine A. In conclusion, our data provide evidence for a pathway of Ag-independent T cell activation via CD5 and CD28, which preferentially stimulates native T cells.

Animals↗
PubMed1993

Ligation of B7 with CD28/CTLA-4 on T cells results in CD40 ligand expression, interleukin-4 secretion and efficient help for antibody production by B cells.

It has been extensively shown that when T cells are co-stimulated with B7-CD28 interaction, a strong proliferative as well as cytolytic T cell response can be induced. In contrast, there exists only indirect evidence that the B7-CD28 interaction is of importance for the induction of T cell helper functions in B cell responses. Here we have used mouse fibroblasts transfected with the human Fc gamma receptor type II and human B7 to address this issue. We found that T cells, when activated through the T cell receptor (TcR)/CD3 complex with monoclonal antibodies and co-stimulated by B7-CD28 interaction, can provide efficient help for the induction of both IgM and IgG production by resting B cells. This helper activity is, at least in part, mediated by the interaction between the CD40 ligand on the T cells and CD40 on the B cells. We also demonstrate that more than one signal to the T cell is required for the induction of the CD40 ligand, one being delivered through the TcR/CD3 complex and the second by ligation of CD28 with the B7 molecule. In addition to the induction of cognate T helper function, we provide evidence that co-stimulation of T cells with B7-CD28 interaction can result in the secretion of both Th1- and Th2-type lymphokines.

Adult↗
PubMed1993

In situ expression of B7/BB1 on antigen-presenting cells and activated B cells: an immunohistochemical study.

B7/BB1 is a physiological ligand for CD28, a receptor expressed on a major subset of T lymphocytes. B7/BB1 has been shown to be expressed on human blood dendritic cells and on in vitro activated (but not resting) B cells and monocytes. Ligation of CD28 with B7/BB1 up-regulates cytokine production and prevents the induction of anergy in T cells activated through TCR/CD3. We examined the in situ expression of B7/BB1 by immunohistochemistry with a novel mAb B7-24. Dendritic cells in skin (Langerhans cells), lymph node sinuses (veiled cells), and T cell zones of spleen and lymph nodes (interdigitating dendritic cells) were strongly positive for B7/BB1. B7/BB1 was also present on fetal thymus dendritic cells located at the cortico-medullar junction and the medulla, but absent in normal adult thymuses. Resident macrophages and endothelial cells did not stain, but in granulomatous inflammations B7/BB1 was found on macrophages and epitheloid cells. A subset of B immunoblasts and of germinal center B cells in lymph node and spleen was also found to express B7/BB1. Our findings on the distribution of B7/BB1 expression in tissues, in particular its expression on professional antigen-presenting cells, further substantiate the putative co-stimulatory role of B7/BB1 in T cell activation in vivo. The presence of B7/BB1 in fetal but not adult thymic medulla suggests a role for B7/BB1 in thymocyte maturation.

Antibodies, Monoclonal↗
PubMed1993

Ligation of the CD5 or CD28 molecules on resting human T cells induces expression of the early activation antigen CD69 by a calcium- and tyrosine kinase-dependent mechanism.

The CD5 and CD28 molecules on T lymphocytes can each exert an accessory role in T-cell activation. Ligands for CD5 and CD28 have been identified as CD72 and B7/BB1 respectively. The function of, and the signal transduction pathways coupled to CD28 have been the subject of extensive studies. In contrast, it is still debated whether CD5 functions as a receptor which directly transduces an independent signal to the T cell. In this paper, it is reported that culture of purified T cells in the presence of either immobilized anti-CD5 monoclonal antibody (mAb) (OKT1, Leu-1 or 10.2) or cross-linked anti-CD28 (9.3) mAb (but not of anti-LFA-1 alpha, anti-LFA-1 beta, or anti-CD7) induces expression of CD69, an early activation marker, in the absence of other activating stimuli. CD69 expression was consistently detectable after 3-24 hr on 20-50% of T cells, within both the CD4 and CD8 subsets. CD45RO- CD45RA+ naive T cells were more responsive than CD45RO+ CD45RA- memory T cells. In the presence of recombinant (r) interleukin-2 (IL-2), anti-CD5- or anti-CD28- induced CD69 expression was further up-regulated, more sustained and, as previously shown, succeeded by IL-2 responsiveness. Simultaneous cross-linking of both CD5 and CD28 enhanced CD69 expression above the levels obtained with optimal amounts of both ligands separately. In the presence of a submitogenic dose of the protein kinase C (PKC) activating agent phorbol 12-myristate 13-acetate (PMA), co-stimulation with anti-CD5 or anti-CD28 increased CD69 expression above that induced by PMA alone. Cross-linking of CD5 or CD28 induces an early rise of cytoplasmic free calcium concentration ([Ca2+)]i) and both this rise and CD69 expression were inhibited by chelation of extracellular Ca2+ with ethyleneglycol-bis-(2-aminoethyl)-tetraacetate (EGTA). Pretreatment of the cells with the tyrosine kinase inhibitor herbimycin A also blocked CD69 expression. The data thus antigen-independent fashion. Moreover it is demonstrated that influx of Ca2+ and tyrosine kinase activity are involved in the signal transduction pathways of both receptors.

Adult↗
PubMed1992

Antibody and B7/BB1-mediated ligation of the CD28 receptor induces tyrosine phosphorylation in human T cells.

CD28 is an adhesion receptor expressed as a 44-kD dimer on the surface of a major subset of human T cells. The CD28 receptor regulates the production of multiple lymphokines, including interleukin 2 (IL-2), by activation of a signal transduction pathway that is poorly understood. Here we show that ligation of CD28 by a monoclonal antibody (mAb) or by a natural ligand, B7/BB1, induces protein tyrosine phosphorylation that is distinct from T cell receptor (TCR)-induced tyrosine phosphorylation. CD28-induced protein tyrosine phosphorylation was greatly enhanced in cells that had been preactivated by ligation of the TCR, or by pretreatment with phorbol esters. Rapid and prolonged tyrosine phosphorylation of a single substrate, pp100, was induced in T cells after interaction with B7/BB1 presented on transfected Chinese hamster ovary (CHO) cells. Anti-B7 mAb inhibited B7/BB1 receptor-induced tyrosine phosphorylation, indicating that B7-CD28 interaction was required. CD28-induced tyrosine phosphorylation was independent of the TCR because it occurred in a variant of the Jurkat T cell line that does not express the TCR. Herbimycin A, a protein tyrosine kinase inhibitor, could prevent CD28-induced tyrosine phosphorylation and CD28-induced IL-2 production in normal T cells. The simultaneous crosslinking of CD28 and CD45, a tyrosine phosphatase, could prevent tyrosine phosphorylation of pp100. These results suggest that specific tyrosine phosphorylation, particularly of pp100, occurs directly as a result of CD28 ligand binding and is involved in transducing the signal delivered through CD28 by accessory cells that express the B7/BB1 receptor. Thus, this particular form of signal transduction may be relevant to lymphokine production and, potentially may provide a means to study the induction of self-tolerance, given the putative role of the costimulatory signal in the induction of T cell activation or anergy.

Antibodies, Monoclonal↗
PubMed1992

Comparative study of cefetamet pivoxil and penicillin V in the treatment of group A beta-hemolytic streptococcal pharyngitis.

The efficacy of cefetamet pivoxil (20 mg/kg and 10 mg/kg b.i.d.) was investigated in an open, prospective, randomized, comparative multicenter trial involving 148 children suffering from group A beta-hemolytic streptococcal (GABHS) pharyngo-tonsillitis. Phenoxymethylpenicillin given for 10 days was used as the reference drug and resulted in 15% treatment failures. After treatment with cefetamet pivoxil 20 mg/kg b.i.d., 2 failures (5.8%) were observed in 34 patients treated for 7 days and 2 (6%) in 33 patients after 10 days treatment. In 8 children treated with cefetamet pivoxil 10 mg/kg b.i.d. for 10 days, 7 were cured and 1 relapsed in the late follow-up. Recruitment for this dosage group is being continued. No serious adverse events occurred. Cefetamet pivoxil, given b.i.d., can be considered an alternative to phenoxymethylpenicillin in the treatment of GABHS pharyngo-tonsillitis.

Acute Disease↗
PubMed1991

Immobilized anti-CD5 together with prolonged activation of protein kinase C induce interleukin 2-dependent T cell growth: evidence for signal transduction through CD5.

Monoclonal antibodies (mAb) identifying the CD5 antigen were used to stimulate human peripheral blood T lymphocytes. Three out of three anti-CD5 mAb, 10.2, OKT1 and anti-Leu-1 induced vigorous proliferation of purified T cells in the presence of 1.6 nM phorbol 12-myristate 13-acetate (PMA). Immobilization of anti-CD5 mAb on a solid support was necessary for the induction of a proliferative response. Neither 1.6 nM PMA, nor immobilized anti-CD5 mAb were mitogenic as a sole stimulus. mAb identifying CD4, CD7, CD11a, CD18, and major histocompatibility complex class I molecules were not comitogenic with PMA. Anti-CD5/PMA-induced cell proliferation proceeded by an interleukin 2 (IL 2)-dependent mechanism, as was demonstrated by the cell surface expression of the p55 chain of the IL 2 receptor (IL 2R), the production of IL 2 and the inhibition of the proliferative response by anti-IL 2R mAb anti-Tac. There was no strict requirement for detectable numbers of monocytes, although cell proliferation could be enhanced by the monocyte-derived cytokines IL 1 and IL 6. Phorbol 12,13-dibutyrate and mezerein could substitute for PMA in this activation pathway, but synthetic diacylglycerols and phorbol esters that do not activate protein kinase C (PKC) could not, indicating a need for prolonged activation of PKC. T cells activated by anti-CD5/PMA are sensitive to inhibition by cyclosporin A (CsA) and by prostaglandin E2 (PGE2). This contrasts with anti-CD28/PMA-induced T cell proliferation, which is resistant to CsA and PGE2. Cell surface expression of CD5 was strongly up-regulated by PMA, whereas CD3 expression was down-regulated. We conclude that T cell activation can be triggered by engagement of CD5 by immobilized anti-CD5 mAb, combined with prolonged activation of PKC. These data support a role for CD5 as an independent signal transducing molecule.

Adult↗
PubMed1990

Crosslinking of the CD5 antigen on human T cells induces functional IL2 receptors.

CD5 is a 67-kDa antigen that is expressed on the membrane of the majority of human T cells, and on a subset of B cells. Previous studies have demonstrated that anti-CD5 monoclonal antibodies (mAb) can provide a helper signal for T cell activation through the TCR/CD3 complex. We now demonstrate that when CD5 is crosslinked by immobilized anti-CD5 mAb in the absence of other activating stimuli, the T cells proliferate in response to recombinant interleukin 2 (rIL2) (but not to rIL4). Four different anti-CD5 mAb (anti-Leu1, 10.2, anti-T1, and OKT1) had a similar effect. IL2 responsiveness could be induced with immobilized anti-CD5 mAb in cultures of purified T cells, but was enhanced by the addition of monocytes, by monocyte culture supernatant, or by the combination of IL1 and IL6. Staining with an anti-IL2 receptor (p55) mAb demonstrated expression of IL2 receptors on about 10% of the anti-CD5-stimulated T cells. Both virgin (CD45RA+) and memory (CD45RO+) T cells were responsive. Our data provide further evidence for the involvement of CD5 in T cell activation.

Adult↗
PubMed1989

Cat-scratch disease with reversible encephalopathy.

A case of cat-scratch disease (CSD) complicated by reversible encephalopathy is presented. Neurological complications of CSD are uncommon. Laboratory and radiological examinations were negative. There was complete recovery.

Cat-Scratch Disease↗
PubMed1985

Characterization of ATP-driven calcium uptake in renal basal-lateral and renal endoplasmic reticulum membrane vesicles.

ATP-driven calcium uptake was studied in basal-lateral membranes and in microsomal fractions, isolated from pig kidney cortex. The uptake is strongly enhanced in conditions where calcium inside the vesicles is precipitated by oxalate (5 mM) or phosphate (40 mM). Both anions were equally effective for the stimulation of calcium uptake in the microsomes but oxalate was less effective than phosphate in the basal-lateral membrane fraction. The active calcium pumps in the renal basal-lateral and microsomal fractions are different transport ATPases characterized by phosphorylated intermediates of 135 kDa and 115 kDa respectively. The subcellular distribution of the 135 kDa and 115 kDa phosphointermediates, reflects the distribution of typical marker enzymes for the basal-lateral membrane and for the endoplasmic reticulum. The calmodulin binding to the 135 kDa polypeptide as estimated by 125I-labelled calmodulin overlay, can be used as a specific marker for the basal-lateral plasma membrane calcium pump.

Adenosine Triphosphate↗