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A Bensussan

Publications and source records attributed to A Bensussan.

At least 19 recordsLinked to original sources
PubMed2006

Involvement of IFNbeta on IFNgamma and nitric oxide (NO) production by bone marrow (BM) cells in response to lipopolysaccharide.

Bone marrow (BM) cells fractioned in Percoll gradients yield a low-density fraction (Fr3) highly enriched in suppressor activity. Previously, it has been demonstrated that BM associated suppressor activity was mediated by early myeloid cells, through a mechanism dependent on endogenous IFNgamma and nitric oxide production after bacterial stimuli, e.g. lipopolysaccharide (LPS). However, the mechanism(s) through which the IFNgamma is produced in BM has not yet been fully elucidated. Therefore, in the present study we investigated the involvement of IL-12, IL-18 and IFNbeta on the production of IFNgamma and nitric oxide in cultures of BM Fr3 cells, and characterized the IFNgamma-producing cells, in response to LPS. The results show that both IL-12 and IFNbeta, but not IL-18, are involved on IFNgamma production. However, only IFNbeta appears to be critical on nitric oxide production. Furthermore, we found that cells of the Thy1.2+CD3+ phenotype produce IFNgamma and are tightly involved on nitric oxide production by BM Fr3 cells. In conclusion, IFNbeta appears to be critical on IFNgamma- and nitric oxide production by BM cells in response to LPS, through a mechanism that is dependent on Thy1.2+CD3+ IFNgamma-producing cells.

Animals↗
PubMed2006

Protocadherin 15 (PCDH15): a new secreted isoform and a potential marker for NK/T cell lymphomas.

Natural killer cells are well known to play an important role in immune defense against tumor development and viral infections. To further characterize new functionally relevant structures in these cells, we studied a series of monoclonal antibodies that we have raised against the NK cell line YT. One of these antibodies previously described as AY19, recognizes a 85 kD surface glycoprotein. Here we report the identification of a new secreted isoform of protocadherin 15, PCDH15C, which represents a potential associated protein for p85. Importantly, whereas protocadherins are absent from the surface of normal hematopoietic cells, we describe, for the first time, that PCDH15 is expressed in cytotoxic tumor-derived T- and NK-cell lines as well as in biopsies of nasal NK/T-cell lymphomas.

Animals↗
PubMed2006

Human decidual NK cells: unique phenotype and functional properties -- a review.

Human decidual NK cells are massively recruited at the site of embryonic implantation (decidua basalis). They differ in many ways from their peripheral blood NK cell counterparts in terms of gene expression, phenotype and functionality. The major subpopulation of decidual NK cells is CD56(bright) whereas the minor subset is CD56(dim), contrasting with the peripheral blood NK cells whose major subpopulation is CD56(dim). Decidual NK cell cytolytic function is much reduced despite the presence of several activating receptors and the essential machinery required for lysis. Decidual NK cells produce a number of cytokines that are not normally secreted by peripheral blood NK cells. Human decidual NK cell potential functions at the maternal-fetal interface are not yet clearly established but several hypotheses are being evaluated, including control of extravillous invasion, control of uterine vascular remodeling, and local anti-viral activity.

Cell Movement↗
PubMed2004

BCL2 and JUNB abnormalities in primary cutaneous lymphomas.

BACKGROUND: BCL2 is upregulated in nodal and extranodal B-cell non-Hodgkin's lymphomas, with a consequent antiapoptotic effect. However, loss of BCL2 has also been noted in some malignancies, suggesting a different molecular pathogenesis. OBJECTIVES: To investigate genomic and protein expression status of BCL2 and to compare the results with that of JUNB in primary cutaneous lymphomas (PCLs). METHODS: We analysed gene copy number of BCL2 and JUNB in 88 DNA samples from 80 patients with PCL consisting of Sézary syndrome/mycosis fungoides (SS/MF), primary cutaneous B-cell lymphoma (PCBCL) and primary cutaneous CD30+ anaplastic large cell lymphoma (C-ALCL) by the use of real-time polymerase chain reaction (PCR) and immunohistochemistry (IHC). Real-time PCR and IHC findings were subsequently compared with the results of additional fluorescent in situ hybridization (FISH) analysis of 23 cases of SS and Affymetrix cDNA expression microarray study of two primary cutaneous T-cell lymphoma (CTCL) cell lines. RESULTS: Real-time PCR analysis showed loss of BCL2 gene copy number in 22 of 80 PCL cases (28%), including 17 of 42 SS/MF, three of 13 C-ALCL and two of 33 PCBCL samples, and gain of BCL2 in four PCBCL samples. Gain of JUNB was identified in 18 of 71 PCL cases (25%), including nine of 35 SS/MF, seven of 13 C-ALCL and two of 31 PCBCL samples. IHC analysis revealed absent nuclear expression of BCL2 protein in 47 of 73 PCL cases, comprising 28 of 36 SS/MF, eight of eight C-ALCL and 11 of 29 PCBCL cases. In contrast, BCL2 protein expression was detected in 26 of 73 PCL cases, consisting of 18 of 29 PCBCL and eight of 36 SS/MF cases. JUNB protein expression was present in tumour cells from 30 of 33 of SS/MF and eight of eight C-ALCL, and was absent in tumour cells from 18 of 27 PCBCL cases. A comparison between BCL2 and JUNB revealed loss of BCL2 and gain of JUNB in five of 35 SS/MF samples, and expression of JUNB protein and absent BCL2 expression in 25 SS/MF and eight of eight C-ALCL cases. In contrast, expression of BCL2 and absent JUNB expression were detected in 67% of PCBCL cases. Additional FISH analysis revealed deletion of BCL2 in 19 of 23 SS cases (83%), including eight cases with BCL2 loss shown by real-time PCR. Furthermore, Affymetrix expression microarray demonstrated decreased expression of proapoptotic and antiapoptotic genes involved in BCL2 signalling pathways such as BOK, BIM, HRK, RASA1 and STAT2 in two CTCL cell lines with BCL2 loss and absent BCL2 expression. Increased expression of JUNB was also identified in the MF cell line. CONCLUSIONS: These findings provide a comprehensive assessment of BCL2 and JUNB status in PCL, and suggest that there is a selection pressure in a subset of CTCL cases for tumour cells showing BCL2 loss and upregulation of JUNB primarily through chromosomal deletion and amplification, respectively.

Genes, bcl-2↗
PubMed2003

Isolation of a CD8alphaalpha+ CD4- tumour T-cell clone with cytotoxic activity from a CD4+ CD8- cutaneous T-cell lymphoma.

BACKGROUND: We have previously established tumour T-cell lines, both from the skin and from the blood of patients with a cutaneous T-cell lymphoma (CTCL). In one patient, the tumour cells and the derived cell lines had a CD3+ CD4+ CD8- phenotype and a trisomy of chromosome 7. They expressed three T-cell receptor (TCR) beta-chain transcripts, but only one was productively rearranged and expressed at the cell membrane. OBJECTIVES: In the present study, we tried to isolate a fast-growing new tumour T-cell line from the same patient. PATIENTS/METHODS: We performed direct cell cloning of the skin tumour lymphocyte population, which led to the isolation of an interleukin-2-dependent highly proliferative T-cell subclone, named Cou-L3, with a CD3+ TCR-Vbeta13+ CD4- CD8alphaalpha+ phenotype. RESULTS: We demonstrated that Cou-L3 was identical to the original clonal tumour CD3+ Vbeta13+ CD4+ CD8- cells, as it expressed the same rearranged TCR-Vbeta13 chain. We further studied the functional activity of these CD8alphaalpha+ Vbeta13+ Cou-L3 cells. We found that these cells exhibited CD3-redirected cytotoxic activity. CONCLUSIONS: An immunophenotypic shift, with a change from a CD4+ to a CD8+ phenotype, has been already reported in association with disease progression in CTCL. However, in these cases, there has been no demonstration that the phenotypic change involved the same T-cell clone. The present study is the first report of the phenotypic heterogeneity of the tumour clonal cell population in CTCL.

Aged↗
PubMed2003

Interaction of cutaneous lymphoma cells with reactive T cells and dendritic cells: implications for dendritic cell-based immunotherapy.

BACKGROUND: Cutaneous T-cell lymphomas (CTCLs) are a heterogeneous group of skin neoplasms that originate from T lymphocytes. An anti-CTCL T-cell immunity has been described but seems to be inefficient to clear CTCL cells. It is not known whether cutaneous dendritic cells (DCs) perpetuate the proliferation of the malignant CTCL cell clone or play a role in the control of this usually slowly progressing disease. OBJECTIVES: To characterize CTCL cell properties in the control of anti-CTCL T cells and to pave the way for a DC-based immunotherapy for CTCL. METHODS: We studied the interaction of a CTCL cell line with DCs and with allogeneic T cells. RESULTS: We found an antigen non-specific capacity of viable but not apoptotic CTCL cells to hamper CD4+ and CD8+ T-cell proliferation in a dose-dependent manner, indicating a suppressive potential of CTCL cells. Both viable and apoptotic CTCL cells were phagocytosed by immature DCs but only apoptotic CTCL cells induced an upregulation of DC maturation markers to a degree which enabled classification of these DCs as semimature. CTCL cells did not respond with proliferation when encountering allogeneic, mature DCs either loaded with CTCL cell material or unloaded, indicating a role for DCs in the induction of anti-CTCL T-cell immunity rather than in perturbation of clonal proliferation. For the loading of DCs with CTCL material lysate seems to be optimal as apoptotic cells were not phagocytosed extensively and necrotic CTCL material induced a partial cellular toxicity in DCs. DCs loaded with CTCL material were cryopreservable without significant loss of DC viability, surface marker expression or allostimulatory activity. CONCLUSIONS: Together, these data argue in favour for a DC-based immunotherapy for CTCL patients and provide an experimental protocol for preparing CTCL cell-loaded DCs.

Apoptosis↗
PubMed2002

Identification of cell surface molecules characterizing human cutaneous T-cell lymphomas.

Primary cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of malignant mature T-cell proliferations most often presenting as mycosis fungoides (MF) or its leukemic variant, Sezary syndrome (SS). No specific cell surface markers are presently available to distinguish the circulating malignant clone from normal lymphocytes. Using the previously established CTCL cell lines, Cou-LS and Pno, we have detected two leucocyte cell surface antigens with aberrant expression on CTCL cells. The NK-receptor (NKR) p140/KIR3DL2 normally expressed by NK and CD8+ T-cells was detected on the surface of CTCL cell lines as well as on freshly isolated CD4+PBL from SS patients. Further on, p140 marked in situ SS cells, distinguishing them from p140-negative tumor cells of patch plaque MF. SC5 is a newly described activation-related intracellular inhibitory receptor expressed on the surface of a minor PBL subset. We found that SC5 expression was significantly increased in SS cells and correlated to p140 expression. Moreover, cross-linking of SC5 molecules inhibited the malignant cell proliferation induced by anti-CD3 mAbs. The identification of these new structures on circulating SS tumor cells seems to be important both for the understanding of CTCL pathophysiology and for the clinical management of SS patients.

Antigens, Surface↗
PubMed2001

CD antigens 2001.

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Antigens, CD↗
PubMed2001

Biological activity of soluble CD100. I. The extracellular region of CD100 is released from the surface of T lymphocytes by regulated proteolysis.

CD100 is the first semaphorin described in lymphoid tissues, where it has been shown to be associated with a serine kinase activity. Semaphorins are molecules involved in axon pathfinding during nerve development and act as repellent guidance cues. In the nervous system semaphorins exist as either membrane-bound or secreted forms. We report here a spontaneous processing of membrane CD100, suggesting that it is also produced as a diffusable semaphorin from lymphoid cells. Monomeric and homodimeric forms of CD100 are expressed by T lymphocytes and CD100-transfected fibroblasts. We demonstrate that CD100 is released through a proteolytic process blocked by metalloprotease inhibitors. In T cells, only soluble CD100 dimers are produced, suggesting that CD100 dimerization is required for proteolysis. In agreement, we observe that increasing membrane dimers strongly favors shedding of the molecule. By expressing a CD100 molecule mutated at cysteine 674 into a COS cell system, we additionally demonstrate that this particular residue in the extracellular domain of the molecule is required for dimerization. Finally, we show that staurosporine, a serine kinase inhibitor, enhances the membrane cleavage of CD100. Together these results demonstrate that membrane CD100 is cleaved by a metalloprotease-dependent process, which is probably regulated by phosphorylation. Mainly, these findings shed light on a possible function for the semaphorin region of CD100 as a long range guidance cue in the immune system.

3T3 Cells↗
PubMed2001

Biological activity of soluble CD100. II. Soluble CD100, similarly to H-SemaIII, inhibits immune cell migration.

CD100 is a human 150-kDa homodimer expressed at the surface of most hemopoietic cells, and its gene belongs to the Ig and semaphorin gene families. Semaphorin genes encode soluble and membrane-bound proteins, most of which have been shown to act as chemorepellents on growth cone guidance. CD100 is discrete, as it is a transmembrane leukocyte surface molecule that can also exist in a soluble form. While our previous studies using mAbs suggested that the transmembrane form of CD100 plays a role in lymphocyte activation, no function was shown for its soluble form. Here, we investigated the effect of soluble CD100 in a cell migration assay; both CD100 spontaneously shed from a stable transfectant and soluble recombinant CD100 inhibited spontaneous and chemokine-induced migration of human monocytes. Interestingly, only the dimeric form of CD100 exerted an effect. Moreover, soluble CD100 inhibited migration of cells from monocytic and B cell lineages. A similar inhibitory effect on migration was observed with H-SemaIII, but not H-SemaIV, semaphorins. In addition, both CD100 and H-SemaIII were recognized by two CD100 mAbs in an ELISA, and one of these mAb abolished the inhibitory effect of each of these semaphorins. We also provide evidence that CD100 and H-SemaIII act through the same receptor on immune cells, which is not neuropilin-1. Furthermore, we describe a function on immune cells for H-SemaIII, a semaphorin to date only studied in the nervous system.

3T3 Cells↗
PubMed2001

CD4(+) cutaneous T-cell lymphoma cells express the p140-killer cell immunoglobulin-like receptor.

Tumor cells of patients with cutaneous T-cell lymphoma (CTCL) have the cell surface phenotype of mature T-helper lymphocytes, and it may be impossible to differentiate them from nonmalignant lymphocytes in skin and blood. Until now, no specific cell membrane marker of CTCL has been reported. In the current study, it is reported for the first time that CTCL cells express the major histocompatibility complex class I binding p140-killer cell immunoglobulin-like receptor, which has been described on a minor subset of natural killer lymphocytes and on a marginal circulating CD8(+) T lymphocyte subset. Interestingly, the molecular characterization of this KIR expressed by CTCL allowed us to isolate a novel allelic form of p140-KIR3DL, resulting in 4 amino acid substitutions, 3 in the extracellular immunoglobulin-like domain of the protein and one in the cytoplasmic region. This finding is likely to be important both for the pathophysiology and for the clinical treatment of patients with CTCL.

Amino Acid Sequence↗
PubMed2001

CD antigens 2001.

The most recent Human Leucocyte Differentiation Antigen Workshop ("HLDA7") took place in 2000 in Harrogate, UK and the proceedings are about to be published (Leucocyte Typing VII). New Sections were introduced in this Workship (Dendritic cells, Stem/progenitor cells, Erythroid cells and Carbohydrate Structures) and monoclonal antibodies were selected for which at least some molecular data were already available (to avoid "blind" screening of reagents against known specificities). A total of more than 80 new CD specificities were established (previously the average was less than 30 new CD specificities per Workshop) and these are listed in this article. There is already evidence for the existence of many new leucocyte surface molecules for study at the next HLDA Workshop (in Adelaide in 2004), and we have listed in this article a number of such potential CD candidates (identified following the production of monoclonal antibodies or via gene cloning). There are also today an increasing number of lineage- and/or stage-restricted leucocyte-associated molecules localised within the cell cytoplasm (or nucleus): they will certainly prove of intense in the future for many laboratories studying human haematopoietic cells (regardless of whether a new "intracellular CD" categorisation scheme is devised for such molecules).

Antigens, CD↗
PubMed2001

Study of cord blood natural killer cell suppressor activity.

We tested the immunosuppressive effect of cord blood (CB) natural killer (NK) cells using highly purified CB NK cells in mixed lymphocyte cultures (MLC) containing autologous CB T cells as responders. Control cultures were done without NK cells. Our findings revealed that CB NK cells induced a dose-dependent inhibition of T lymphocyte proliferation as evidenced by decreased 3H-thymidine incorporation in MLC. The T cell alloproliferation was significantly decreased in the presence of an NK cell to responder cell ratio of 0.1, 0.2 or 0.4 compared with control cultures done without NK cells (p=0.02, 0.003 and 0.0002, respectively). T lymphocyte inhibition was also achieved using irradiated CB NK cells and still demonstrable on addition of disparate CB NK and T cells to the MLC. In agreement with previous reports, adult blood NK cells inhibited the alloreactive T cells in the MLC using adult T lymphocytes as responders. Compared to control cultures done without NK cells, statistically significant inhibition of 3H-thymidine incorporation in MLC was observed at a ratio of NK cells to responder cells ratio of 0.2 or 0.4 (p=0.02). To investigate the mechanism whereby CB NK cells can interfere with the development of alloreactive T cells in MLC, we measured the tumour necrosis factor-alpha (TNF-alpha) concentrations in MLC supernatants using NK cell-depleted or unseparated CB mononuclear cells (MNC) as responders. The results revealed significantly high levels of TNF-alpha in the absence of NK cells (p=0.007). We conclude that CB NK cells suppress alloreactive T lymphocytes as do their counterparts in adult blood. However, the high NK to T cell ratio in CB could contribute to a more marked suppressive potential compared to that in adult blood. The mechanism of NK-mediated inhibition is likely related to disruption of the TNF-alpha pathway of T-lymphocyte activation.

Adult↗
PubMed2001

Functional characterization of neurotensin receptors in human cutaneous T cell lymphoma malignant lymphocytes.

Cutaneous T cell lymphomas are a clonal proliferation of CD4+ T lymphocytes primarily involving the skin. Mycosis fungoides is an epidermotropic CD4+ cutaneous T cell lymphoma, and a more aggressive form, Sezary syndrome, occurs when the malignant cells become nonepidermotropic. The role of neuropeptides in the growth and chemotaxis capacity of cutaneous T cell lymphoma cells remains unknown. In this report, we found that cutaneous T cell lymphoma cells, similarly to normal resting or activated peripheral lymphocytes, were able to bind neurotensin. We used an interleukin-2-dependent cutaneous T cell lymphoma malignant T cell line derived from cutaneous T cell lymphoma lesions in order to study the role of neurotensin in the proliferation and migration of these malignant cells. First, we determined that the malignant cells expressed neurotensin receptors on their cell membrane. Functional results indicated that neurotensin did not stimulate the growth of the cell line. In contrast, this neuropeptide inhibited the proliferation of the tumor cells in response to exogenous interleukin-2. Furthermore, we found that neurotensin enhanced both spontaneous and chemoattractant-induced migration of the malignant cells. This suggests that neurotensin in skin can play a role in the disease by locally limiting the growth of the cutaneous T cell lymphoma tumor cells in response to cytokines and by enhancing their chemotaxis capacity.

CD4-Positive T-Lymphocytes↗
PubMed2001

Increased expression of a novel early activation surface membrane receptor in cutaneous T cell lymphoma cells.

Using a newly generated monoclonal antibody we identified the 96 kDa transmembrane receptor SC5 expressed simultaneously on a human Sezary cell line and a minor T cell subset in normal individuals. SC5 antigen was detected mostly on CD45RO+ lymphocytes from both CD4+ and CD8+ subsets as well as on natural killer and B lineage cells. SC5 surface expression increased very early after polyclonal stimulation of CD3+ cells due to the transfer of intracellular SC5 molecules to the cell membrane. Engagement of SC5 receptor by its monoclonal antibody inhibited the anti-CD3-induced proliferation and cytokine secretion of peripheral blood T cells and cell clones, whereas SC5 monoclonal antibody did not affect the cytotoxic activity of CD8+ T cell clones. Extensive phenotypic analysis revealed that the percentage of SC5+ CD4+ circulating lymphocytes in Sezary syndrome patients was significantly increased in comparison with controls (p < 0.01) and correlated with the morphologically detected percentage of Sezary syndrome cells in peripheral blood (p < 0.001). In one patient we clearly demonstrated that the circulating malignant T cells coexpress SC5 molecules. Importantly, ligation of SC5 receptor in a cutaneous T cell lymphoma cell line profoundly inhibited the anti-CD3-induced proliferation. Consequently, the expression of SC5 receptor in the peripheral blood of Sezary syndrome patients may serve not only to detect the presence of circulating malignant CD4+ cells but also as a target for immunotherapy.

Antibodies, Monoclonal↗
PubMed2001

Erythrodermic cutaneous T-cell lymphoma with disseminated pustulosis. Production of high levels of interleukin-8 by tumour cells.

Interleukin (IL) -8 is a neutrophil chemoattractant cytokine with proinflammatory and growth-promoting activities, which is involved in the pathogenesis of several inflammatory diseases. It is found in high amounts in lesional biopsies of pustular diseases such as psoriasis and palmoplantar pustulosis. We report a 50-year-old woman with a 10-year history of erythroderma with disseminated pustulosis. Skin biopsies showed an epidermotropic infiltrate composed of atypical CD4+ CD8+ lymphocytes with numerous admixed neutrophils. Peripheral blood flow cytometric analysis revealed a major clonal subset of CD3+ CD4+ CD8+ T-cell receptor Vbeta22+ atypical lymphocytes. Bone marrow biopsy, lymph node biopsy and computed thoracoabdominal tomography were normal. Serologies for human T-cell lymphotropic virus type I and human immunodeficiency virus were negative. Our patient's status deteriorated despite topical (nitrogen mustard, psoralen plus ultraviolet A) and systemic (interferon, methotrexate, multiagent chemotherapy) treatments, and she finally died. We showed that our patient's peripheral blood lymphocytes (PBL) spontaneously produced high amounts of IL-8. In contrast, PBL of patients with classical Sézary syndrome produced lower amounts of IL-8. The production of IL-8 by tumour T cells could explain this unusual clinical and histopathological presentation of cutaneous T-cell lymphoma as disseminated pustulosis.

Dermatitis, Exfoliative↗