Biomedical subjects

D Olive

Publications and source records attributed to D Olive.

At least 37 records · Page 2Linked to original sources

PubMed2002

Identification of precursors of leukemic dendritic cells differentiated from patients with acute myeloid leukemia.

Dendritic cells (DC) can facilitate immune responses that might help in the induction of effective antitumor T cell responses. We reported previously that leukemic blasts from selected patients with acute myeloid leukemia (AML) were able to differentiate in vitro into cells with mature DC features. However, despite the use of a wide variety of cytokine combinations, leukemic DC could not be obtained from all AML patients. In this study, we investigated in a wide range of AML patients (n = 30), the nature and functional characteristics of the blast compartment that can be induced to acquire DC features in vitro. Our results demonstrate that leukemic DC generated in the presence of GM-CSF, IL-4 and matured with CD40L, are composed of two major subsets: DC derived from CD14(+) leukemic cells and leukemic DC derived from in vivo expanded circulating blood myeloid DC (MDC). Leukemic DC of both subsets exhibited DC morphology, had a phenotype of mature DC, and could induce a potent proliferative response of naive CD4(+) T cells. Moreover, both subsets produced large amounts of IL-12p70 and leukemic CD14(+)-derived DC could induce a potent Th1 response. These results can be considered as a prerequisite before the design of vaccine immunotherapy protocols for the adjuvant treatment of AML patients.

Acute Disease↗

PubMed2002

Leukemic dendritic cells: potential for therapy and insights towards immune escape by leukemic blasts.

Dendritic cells (DCs) are a system of potent antigen-presenting cells (APCs) specialized to initiate primary immune responses. DCs are considered important elements in the induction of specific antitumor cytotoxic effectors. At present, because of potential therapeutic implications, the critical role of DCs in cancer patients is under intensive investigation. Interactions between DCs and acute myeloid leukemia cells represent an attractive model for the study of DC physiology. Moreover, DCs can be a valuable therapeutic tool for the adjuvant treatment of leukemic patients. However, DC subsets in vivo may also be affected by leukemogenesis and may contribute to the escape of leukemia from immune control. The aim of this review is to shed further light on this paradoxical picture where the line between immune tolerance and immune defense is narrow.

Antigen Presentation↗

PubMed2002

Recovery of lymphocyte and dendritic cell subsets following reduced intensity allogeneic bone marrow transplantation.

Approaches using reduced conditioning regimens have been developed to obtain minimal procedure-related toxicity. Such novel therapeutic options are being explored with good preliminary results concerning feasibility and engraftment. However, many aspects remain under-evaluated and few data are available about immune and dendritic cell (DC) reconstitution after these highly immunosuppressive regimens. We present here our data in 20 patients receiving allogeneic bone marrow transplantation (allo-BMT) using a reduced preparative regimen. We evaluated in the first 3 months following allo-BMT, several immunological parameters including DC subsets, and compared these to historical results obtained in a group of myeloablative allo-BMT patients. We found an early recovery of leukocytes, CD8+ and NK lymphocytes. We also found a trend towards an improved B cell recovery. These results are somewhat in contrast to the altered immune recovery observed in the myeloablative setting. In addition, we found a significant early circulating DC recovery. Circulating blood DCs were also found to be of full donor origin as assessed by FISH in sex-mismatched pairs. Nevertheless, naive CD4 + CD45RA + T cells were found to be profoundly reduced following such regimens.Collectively, these data further enhance the overall benefits of reduced intensity regimens and the need for a stringent biological monitoring for assessment of the potential advantages of reduced intensity allo-BMT in comparison with conventional allo-BMT.

Adult↗

PubMed2001

Circulating blood dendritic cells from myeloid leukemia patients display quantitative and cytogenetic abnormalities as well as functional impairment.

Dendritic cells (DCs) are responsible for the initiation of immune responses. Two distinct subsets of blood DCs have been characterized thus far. Myeloid DCs (MDCs) and plasmacytoid monocytes (PDCs) were shown to be able to promote polarization of naive T cells. This study shows a dramatic quantitative imbalance in both circulating blood DC subsets in 37 patients with acute myeloid leukemias. Eleven patients (30%) displayed a normal quantitative profile (MDC mean, 0.37% +/- 0.21%; range, 0.01% to 0.78%; PDC mean, 0.21% +/- 0.24%; range, 0.04% to 0.62%), whereas 22 (59%) showed a tremendous expansion of MDCs (9 patients: mean, 16.76% +/- 14.03%; range, 1.36% to 41%), PDCs (4 patients: mean, 7.28% +/- 6.84%; range, 1% to 14%), or both subsets (9 patients: MDC mean, 10.86% +/- 12.36%; range, 1.02% to 37.1%; PDC mean, 4.25% +/- 3.78%; range, 1.14% to 13.04%). Finally, in 4 patients (11%), no DC subsets were detectable. Both MDC and PDC subsets exhibited the original leukemic chromosomal abnormality. Ex vivo, leukemic PDCs, but not leukemic MDCs, had impaired capacity for maturation and decreased allostimulatory activity. Also, leukemic PDCs were altered in their ability to secrete interferon-alpha. These data provide evidence that DC subsets in vivo may be affected by leukemogenesis and may contribute to leukemia escape from immune control.

Animals↗

PubMed2001

The TNF superfamily members LIGHT and CD154 (CD40 ligand) costimulate induction of dendritic cell maturation and elicit specific CTL activity.

LIGHT is a recently identified member of the TNF superfamily that is up-regulated upon activation of T cells. Herpesvirus entry mediator, one of its receptors, is constitutively expressed on immature dendritic cells (DCs). In this report, we demonstrate that LIGHT induces partial DC maturation as demonstrated by Ag presentation and up-regulation of adhesion and costimulatory molecules. LIGHT-stimulated DCs show reduced macropinocytosis and enhanced allogeneic stimulatory capacity but fail to produce significant amounts of IL-12, IL-6, IL-1beta, or TNF-alpha compared with unstimulated DCs. However, LIGHT cooperates with CD154 (CD40 ligand) in DC maturation, with particular potentiation of allogeneic T cell proliferation and cytokine secretion of IL-12, IL-6, and TNF-alpha. Moreover, LIGHT costimulation allows DCs to prime in vitro-enhanced specific CTL responses. Our results suggest that LIGHT plays an important role in DC-mediated immune responses by regulating CD154 signals and represents a potential tool for DC-based cancer immunotherapy.

Animals↗

PubMed2001

Surface expression and function of p75/AIRM-1 or CD33 in acute myeloid leukemias: engagement of CD33 induces apoptosis of leukemic cells.

p75/AIRM-1 is a recently identified inhibitory receptor expressed by natural killer and myeloid cells displaying high homology with CD33. Crosslinking of p75/AIRM-1 or CD33 has been shown to sharply inhibit the in vitro proliferation of both normal myeloid cells and chronic myeloid leukemias. In this study, we analyzed acute myeloid leukemic cells for the expression of p75/AIRM-1. p75/AIRM-1 marked the M5 (11/12) and M4 (2/2) but not the M1, M2, and M3 subtypes according to the French-American-British classification. Cell samples from 12 acute myeloid leukemias were cultured in the presence of granulocyte/macrophage colony-stimulating factor. Addition to these cultures of anti-CD33 antibody resulted in approximately 70% inhibition of cell proliferation as assessed by [(3)H]thymidine uptake or by the recovery of viable cells. Anti-p75/AIRM-1 antibody exerted a strong inhibitory effect only in two cases characterized by a high in vitro proliferation rate. After crosslinking of CD33 (but not of p75/AIRM-1), leukemic cells bound Annexin V and displayed changes in their light-scattering properties and nucleosomal DNA fragmentation, thus providing evidence for the occurrence of apoptotic cell death. Remarkably, when anti-CD33 antibody was used in combination with concentrations of etoposide insufficient to induce apoptosis when used alone, a synergistic effect could be detected in the induction of leukemic cell death. These studies provide the rationale for new therapeutic approaches in myeloid leukemias by using both chemotherapy and apoptosis-inducing mAbs.

Acute Disease↗

PubMed2001

The C-class chemokine lymphotactin costimulates the apoptosis of human CD4(+) T cells.

Clonal expansion of activated T cells is controlled by homeostatic mechanisms leading to cell death of a large proportion of the cells. The CD3/TcR pathway induces cell death, mostly when triggered in the absence of costimulatory signal. The unique T cell-specific chemokine of the C class, lymphotactin (Lptn), has recently been shown to inhibit the production of Th1-type lymphokines in human CD4(+) T cells. The present study shows the ability of Lptn to costimulate the death of CD4(+) T lymphocytes triggered through CD3/TCR. The Lptn-mediated increased cell death exhibited characteristic features of apoptosis, as mainly determined by DNA fragmentation and exposure of an apoptotic-specific mitochondrial antigen. This apoptosis was dependent on Fas/FasL signaling, was not rescued by addition of interleukin 2, and proceeded with a predominant processing of both initiator procaspase-9 and effector procaspase-7. These caspase activities were further evidenced by specific cleavage of poly(ADP-ribose) polymerase (PARP) and CD3/TCR zeta-chain, but not DNA fragmentation factor (DFF45). This study demonstrates that the functional repertoire of Lptn in the regulation of human CD4(+) T-lymphocyte activation includes the ability to costimulate apoptosis.

Amino Acid Chloromethyl Ketones↗

PubMed2001

The tyrosine kinase Hck is an inhibitor of HIV-1 replication counteracted by the viral vif protein.

The virus infectivity factor (Vif) protein facilitates the replication of human immunodeficiency virus type 1 (HIV-1) in primary lymphocytes and macrophages. Its action is strongly dependent on the cellular environment, and it has been proposed that the Vif protein counteracts cellular activities that would otherwise limit HIV-1 replication. Using a glutathione S-transferase pull-down assay, we identified that Vif binds specifically to the Src homology 3 domain of Hck, a tyrosine kinase from the Src family. The interaction between Vif and the full-length Hck was further assessed by co-precipitation assays in vitro and in human cells. The Vif protein repressed the kinase activity of Hck and was not itself a substrate for Hck phosphorylation. Within one single replication cycle of HIV-1, Hck was able to inhibit the production and the infectivity of vif-deleted virus but not that of wild-type virus. Accordingly, HIV-1 vif- replication was delayed in Jurkat T cell clones stably expressing Hck. Our data demonstrate that Hck controls negatively HIV-1 replication and that this inhibition is suppressed by the expression of Vif. Hck, which is present in monocyte-macrophage cells, represents the first identified cellular inhibitor of HIV-1 replication overcome by Vif.

Amino Acid Sequence↗

PubMed2001

Validation study of nonsurgical diagnosis of endometriosis.

OBJECTIVE: To determine whether the surgical diagnosis of endometriosis can be predicted using symptoms, signs, and ultrasound findings. DESIGN: Prospective study (study sample); retrospective record review (test sample). SETTING: Hospital of Desio (study sample) and Mangiagalli Hospital (test sample), Italy. PATIENT(S): Ninety women scheduled to undergo laparoscopy or laparotomy (study sample); 120 women who underwent laparoscopy (test sample). INTERVENTION: The study sample group was interviewed before surgery about infertility and dysmenorrhea, dyspareunia, and noncyclic pelvic pain and each member had a pelvic examination and a transvaginal ultrasound. At surgery, endometriosis was noted. For the test sample, the same information was abstracted from medical records after laparoscopy. MAIN OUTCOME MEASURE(S): The ability of symptoms, signs, and ultrasound to predict endometriosis at surgery. A classification tree was developed with the study sample and evaluated with the test sample. RESULT(S): Ovarian endometriosis, but not nonovarian endometriosis, could be reliably predicted with noninvasive tools. Ultrasound and examination best predicted ovarian endometriosis, correctly classifying 100% of cases with no false positive diagnoses in the study sample. Similar results were found in the test sample. CONCLUSION(S): Noninvasive tools may be used to identify women with ovarian, but not nonovarian endometriosis, with excellent agreement with surgical diagnosis.

Adult↗

PubMed2001

Primary plasma cell leukaemia: a report of 18 cases.

Primary plasma cell leukaemia (P-PCL) is a variant of multiple myeloma (MM) first diagnosed in the leukemic phase, with >2000/mm(3) circulating plasma cells (PCs) and plasmacytosis >20% of the white cell count. We investigated the clinical characteristics, therapy, immunophenotype and prognosis factors of 18 patients. Common features at diagnosis were asthenia (seven patients), renal insufficiency (ten patients), bone pain (seven patients), splenomegaly or hepatomegaly (five patients). Hypercalcemia was present at diagnosis in seven patients and was the most potent poor prognosis factor (P<0.05). Most patients (16 out of 18) were treated with an anthracyclin containing regiment; complete remission was attained in one patient and partial remission in 11 patients while six patients had no response. The median survival time from diagnosis was 7 months (2--12, 95% confidence interval), but response to treatment had favorable predictive value (P<0.05). The PCs were usually positive for mature B-cell markers (PCA-1, CD38). They expressed integrins which may increase their binding to endothelial cells and thus participate in PCL physiopathology by favoring plasmocyte extramedullary spread.

Adult↗

PubMed2001

Large granular lymphocytes (LGL) following non-myeloablative allogeneic bone marrow transplantation: a case report.

We report here the first case of large granular lymphocytes (LGL) expansion following non-myeloablative allo-BMT for chronic myeloid leukemia. We characterized the morphologic, phenotypic and functional features of the LGL subset amplified in vivo 14 months after allo-BMT. Our results indicate that LGL can mediate in vitro a cytolytic activity on tumor cells. In vivo, the timing of the LGL expansion was associated with a sustained complete molecular remission. These observations suggest that LGL are a subset with the properties of effector lymphocytes which may contribute to the graft-versus-tumor effect.

Bone Marrow Transplantation↗

PubMed2001

MAGE-A genes are not expressed in human leukemias.

Immunotherapy is promising to improve the prognosis of human leukemias, at least as adjuvant treatment. Tumor-associated antigens such as antigens encoded by MAGE-A1, -A2, -A3, -A4, -A6 and -A12 genes might provide tools in this field. We demonstrated recently that the presentation peptides encoded by MAGE-A genes might make leukemic blasts suitable targets to cytolytic T lymphocytes. We reported previously negative data of MAGE-A1 gene expression in hematological malignancies, but in further studies positive results of MAGE-A gene expression were published in some subtypes of hematological malignancies such as T leukemia, myeloma and Hodgkin's disease. This led us to enlarge the screening of MAGE-A gene expression in human leukemias. In the RT-PCR screening of a large panel including 154 patients, only weak signal were detected in a few samples. We conclude that MAGE-A genes are not expressed in human leukemias.

Antigens, Neoplasm↗

PubMed2001

Novel CD28-responsive enhancer activated by CREB/ATF and AP-1 families in the human interleukin-2 receptor alpha-chain locus.

The interaction of interleukin-2 (IL-2) with its receptor (IL-2R) critically regulates the T-cell immune response, and the alpha chain CD25/IL-2Ralpha is required for the formation of the high-affinity receptor. Tissue-specific, inducible expression of the IL-2Ralpha gene is regulated by at least three positive regulatory regions (PRRI, PRRII, and PRRIII), but none responded to CD28 engagement in gene reporter assays although CD28 costimulation strongly amplifies IL-2Ralpha gene transcription. By DNase I hypersensitivity analysis, we have identified a novel TCR-CD3- and CD28-responsive enhancer (CD28rE) located 8.5 kb 5' of the IL-2Ralpha gene. PRRIV/CD28rE contains a functional CRE/TRE element required for CD28 signaling. The T-cell-specific, CD28-responsive expression of the IL-2Ralpha gene appears controlled through PRRIV/CD28rE by cooperation of CREB/ATF and AP-1 family transcription factors.

Activating Transcription Factors↗

PubMed2000

Reciprocal expression of the TNF family receptor herpes virus entry mediator and its ligand LIGHT on activated T cells: LIGHT down-regulates its own receptor.

The TNF receptor (TNFR) family plays a central role in the development of the immune response. Here we describe the reciprocal regulation of the recently identified TNFR superfamily member herpes virus entry mediator (HVEM) (TR2) and its ligand LIGHT (TL4) on T cells following activation and the mechanism of this process. T cell activation resulted in down-regulation of HVEM and up-regulation of LIGHT, which were both more pronounced in CD8(+) than CD4(+) T lymphocytes. The analysis of HVEM and LIGHT mRNA showed an increase in the steady state level of both mRNAs following stimulation. LIGHT, which was present in cytoplasm of resting T cells, was induced both in cytoplasm and at the cell surface. For HVEM, activation resulted in cellular redistribution, with its disappearance from cell surface. HVEM down-regulation did not rely on de novo protein synthesis, in contrast to the partial dependence of LIGHT induction. Matrix metalloproteinase inhibitors did not modify HVEM expression, but did enhance LIGHT accumulation at the cell surface. However, HVEM down-regulation was partially blocked by a neutralizing mAb to LIGHT or an HVEM-Fc fusion protein during activation. As a model, we propose that following stimulation, membrane or secreted LIGHT binds to HVEM and induces receptor down-regulation. Degradation or release of LIGHT by matrix metalloproteinases then contributes to the return to baseline levels for both LIGHT and HVEM. These results reveal a self-regulating ligand/receptor system that contributes to T cell activation through the interaction of T cells with each other and probably with other cells of the immune system.

CD4-Positive T-Lymphocytes↗

PubMed2000

CD28 utilizes Vav-1 to enhance TCR-proximal signaling and NF-AT activation.

The mechanism through which CD28 costimulation potentiates TCR-driven gene expression is still not clearly defined. Vav-1, an exchange factor for Rho GTPases thought to regulate, mainly through Rac-1, various signaling components leading to cytokine gene expression, is tyrosine phosphorylated upon CD28 engagement. Here, we provide evidence for a key role of Vav-1 in CD28-mediated signaling. Overexpression of Vav-1 in Jurkat cells in combination with CD28 ligation strongly reduced the concentration of staphylococcus enterotoxin E/MHC required for TCR-induced NF-AT activation. Surprisingly, upon Vav-1 overexpression CD28 ligation sufficed to activate NF-AT in the absence of TCR engagement. This effect was not mediated by overexpression of ZAP-70 nor of SLP-76 but necessitated the intracellular tail of CD28, the intactness of the TCR-proximal signaling cascade, the Src-homology domain 2 (SH2) domain of Vav-1, and SLP-76 phosphorylation, an event which was favored by Vav-1 itself. Cells overexpressing Vav-1 formed lamellipodia and microspikes reminiscent of Rac-1 and Cdc42 activation, respectively, for which the SH2 domain of Vav-1 was dispensable. Together, these data suggest that CD28 engagement activates Vav-1 to boost TCR signals through a synergistic cooperation between Vav-1 and SLP-76 and probably via cortical actin changes to facilitate the organization of a signaling zone.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Human acute myeloid leukemia CD34+/CD38- progenitor cells have decreased sensitivity to chemotherapy and Fas-induced apoptosis, reduced immunogenicity, and impaired dendritic cell transformation capacities.

The destruction of cells capable of initiating and maintaining leukemia challenges the treatment of human acute myeloid leukemia. Recently, CD34+/CD38- leukemia progenitors have been defined as new leukemia-initiating cells less mature than colony-forming cells. Here we show that CD34+/CD38- leukemia precursors have reduced in vitro sensitivity to daunorubicin, a major drug used in leukemia treatment, in comparison with the CD34+/CD38+ counterpart, and increased expression of multidrug resistance genes (mrp/lrp). These precursors show lower expression of Fas/Fas-L and Fas-induced apoptosis than CD34+/CD38+ blasts. Moreover, the CD34+/CD38- leukemic subpopulation induces a weaker mixed leukocyte reaction of responding T-lymphocytes than the CD34+/CD38+ leukemic counterpart, either in a MHC-unmatched or MHC-matched settings. This weaker immunogenicity could be linked to lower expression on CD34+/CD38- leukemia precursors of major immune response molecules (MHC-DR, LFA-3, B7-1, or B7-2) than CD34+/CD38+ leukemic cells. Nonetheless, the susceptibility of the immature CD38- precursors to cytotoxicity was not different from the sensitivity of the CD38+ counterpart. Finally, CD34+/CD38- leukemia precursors, in contrast with CD38+ precursors, failed, under appropriate conditions, to differentiate into dendritic cells, a central step for antigen recognition. This is to our knowledge the first demonstration that the very immature phenotype of CD34+/CD38- leukemic progenitors confers both chemotherapy resistance and decreased capacities to induce an immune response. Because the susceptibility of the immature leukemia cells as cytotoxic targets is maintained, our data underline the importance of improving the initial steps of leukemia recognition, more particularly by defining optimal conditions of dendritic cell transformation of the very immature hematopoietic precursors.

ADP-ribosyl Cyclase↗

PubMed2000

The C-class chemokine, lymphotactin, impairs the induction of Th1-type lymphokines in human CD4(+) T cells.

Chemokines are involved in the regulation of leukocyte migration and for some of them, T-cell costimulation. To date, the only direct property of lymphotactin (Lptn), the unique member of the C class of chemokines, consists of T-cell chemoattraction. This report describes a novel function for Lptn in human T-lymphocyte biology, by demonstrating the direct ability of Lptn to both inhibit and costimulate CD4(+) and CD8(+) T-cell activation, respectively. Lptn but not RANTES inhibited CD4(+) T-cell proliferation, through a decreased production of Th1 (interleukin [IL]-2, interferon [IFN]-gamma) but not Th2 (IL-4, IL-13) lymphokines, and decreased IL-2R alpha expression. Transfections in Jurkat cells showed a Lptn-mediated transcriptional down-regulation of gene-promoter activities specific for Th1-type lymphokines, as well as of nuclear factor of activated T cells (NF-AT) but not AP-1 or NF-KB enhancer activities. This suppressive action of Lptn could be compensated by overexpression of NF-ATc but not NF-ATp. CD4(+) T-cell proliferation was completely restored by exogenous IL-2 or reversed by pertussis toxin, wortmannin, and genistein, suggesting the involvement of multiple partners in Lptn signaling. In contrast to CD4(+) cells, Lptn exerted a potent costimulatory activity on CD8(+) T-cell proliferation and IL-2 secretion. These data provide important insights into the role of Lptn in differential regulation of normal human T-cell activation and its possible implication in immune response disorders. (Blood. 2000;96:420-428)

Androstadienes↗

PubMed2000

Expression of gene MAGE-A4 in Reed-Sternberg cells.

Genes of the MAGE-A family are expressed in several types of solid tumors but are silent in normal tissues with the exception of male germline cells, which do not carry HLA molecules.Therefore, peptides encoded by MAGE-A genes are strictly tumor-specific antigens that can be recognized by CTL and constitute promising targets for immunotherapy. The expression of 6 genes of the MAGE-A family was tested with reverse transcriptase-polymerase chain reaction in lymphoma samples. Among 38 samples of non-Hodgkin lymphoma, 1 anaplastic large cell lymphoma expressed genes MAGE-A1, -A2, -A3, -A4, and -A12, and 1 lymphoepithelioid T-cell lymphoma expressed gene MAGE-A4. Five of 18 samples (28%) from patients with Hodgkin disease expressed gene MAGE-A4. In tissue sections, staining by a monoclonal antibody that recognizes the MAGE-A4 protein was observed in 11 of 53 samples (21%) from patients with Hodgkin disease. In the positive samples, the Reed-Sternberg cells were strongly stained whereas the surrounding cells were not. These results indicate that Hodgkin disease may be a target for specific immunotherapy involving MAGE-A4 antigens.

Antibodies, Monoclonal↗