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C Jasmin

Publications and source records attributed to C Jasmin.

At least 73 records · Page 4Linked to original sources
PubMed1994

A new cytokine (IK) down-regulating HLA class II: monoclonal antibodies, cloning and chromosome localization.

The role of HLA class II Antigens in the control of the immune response is determined not only by the genetic polymorphism of these molecules, but also by their density on the cell surface. It is therefore essential to identify the signals that modulate HLA Class II gene activity in normal and neoplastic cells. We have purified a cytokine (IK factor, 19 kDa) secreted by the leukemic cell line K562 and several cancer cells, which inhibits HLA Class II antigen induction by IFN-gamma. We produced specific mAbs which antagonize the biological effect of IK in colon carcinoma Colo 205 cells induced to express HLA-DR molecules by IFN-gamma. Moreover, in Colo 205, HLA-DR can also be induced by the protein synthesis inhibitor Cycloheximide (0.1 micrograms ml-1); and addition of IK factor almost completely abolishes HLA class II expression. We have also performed the cloning and the sequencing of a specific cDNA. This probe recognizes a 2.1 Kb mRNA in different cell types. The nucleotide sequence exhibits no homologies with known cytokines. IK gene localization shows that it maps on chromosome 2p15-p14. The transient transfection of the cDNA in COS cells induces the secretion of a biologically active 19 kDa protein which is recognized in Western blot by 1C5B11 blocking mAb. This paper reports the characterization of a new cytokine down-regulating HLA class II Antigens, whose analysis will help to better understand HLA class II gene regulation and the mechanism of escape from immunorecognition in cancer cells.

Amino Acid Sequence↗
PubMed1993

Human melanoma cells express a functional interleukin-2 receptor.

Flow cytometric analysis reveals that 5 human melanoma cell lines (M14, IGR3, ME1477, JUSO, GLL19) express both alpha and beta chain of the interleukin 2 receptor (IL-2R alpha and IL-2R beta). These chains are able to specifically bind IL-2 and to form high-affinity heterodimers (IL-2R alpha beta). Analysis of poly A+ RNAs by Northern blot reveals the presence of typical transcripts for both the IL-2R alpha gene (3.6 kb) and the IL-2R beta gene (4 kb). Reverse transcription/polymerase chain reaction analysis allowed transcripts for the IL2R gamma (p64) gene to be detected in 3 of these melanoma cell lines (M14, IGR3, ME 1477). Incubation with human recombinant IL-2 modifies in IL-2R alpha+beta+gamma+ (M14) the expression of several surface molecules: down-regulation of ICAM-1, HLA class I and HLA-DR and up-regulation of CD44. IL-2 is also active on IL-2 alpha+beta+gamma- cell lines since it decreases ICAM-1 and HLA class-II expression at the surface of JUSO cells. Down-regulation of ICAM-1, whose expression in melanoma cells is a marker of tumor progression, is detectable within 3 hr in M14 cells and is maximal after 48 hr incubation, at IL-2 concentrations corresponding to the high-affinity heterodimers. This feature is specific since it is partially inhibited by MAbs directed against the IL-2 binding site of the IL-2R alpha (MAR93, 10T14) and IL-2R beta (MiK beta 1, TU27) chains. Our data support the notion of a direct effect of IL-2 on human melanoma cells. Modulation of the expression of surface molecules which is important for the interaction with immunocompetent cells or for tumor progression, could have a role to play during in vivo IL-2 treatment of human melanomas.

Antigens, Neoplasm↗
PubMed1993

IL2-R alpha chain inhibitory factor (p29) produced by HIV-infected macrophages: cell target and mode of action.

We recently reported that HIV-infected adherent cells spontaneously produce a 29-kDa protein (p29), most probably of nonviral origin, which inhibits expression of the IL2R alpha chain on activated normal T cells. Studying the mode of action of this molecule, we observed that monocyte depletion of normal PBMC either by plastic adherence or by complement-mediated cytotoxicity using macrophage-specific monoclonal antibodies abrogated the inhibitory effect of p29. The biological activity of p29 in adherent cell-depleted PBMC could be restored either with rIL1 or with as little as 10(5) autologous adherent cells/ml. Moreover, p29 could not inhibit IL1 biologic activity, nor its binding to IL1 receptor. In addition, p29 could not inhibit the production of IL1 and TNF alpha by normal adherent cells. Positive and negative cell sorting of normal T cells as well as two-color immunofluorescence studies revealed that CD8+ subsets are the main cell targets of p29, which also mediated an impaired generation of alloantigen-specific CTL. Conversely, only a slight inhibitory activity could be detected in highly purified CD4+ cells. Our findings suggest that HIV-induced production of p29 inhibitory factor by adherent cells may be involved in mechanisms responsible for some of the impaired cytotoxic functions observed in AIDS patients.

CD8 Antigens↗
PubMed1993

The IL-2 receptor present on human embryonic fibroblasts is functional in the absence of P64/IL-2R gamma chain.

In this study, we have investigated the IL-2R gamma gene expression in several human embryonic fibroblasts which express other components of the IL-2 receptor (IL-2R). Polymerase chain reaction did not allow us to detect IL-2R gamma transcripts in these cells but the functionality of the IL-2R alpha beta was not affected. Indeed, in the human IL-2R alpha+beta+gamma- embryonic lung fibroblasts ICIG-7, IL-2 induced identical phenomena to those previously reported in lymphoid cells: rapid internalization of the IL-2R alpha beta-IL-2 complex, specific phosphorylation of cellular proteins (56 and 38 kDa) and up-regulation of ICAM-1 expression. IL-2 induction of ICAM-1 was only observed in sparse cultures and for IL-2 concentrations over 180 pM. We have also observed, in these fibroblastic cells, the up-regulation of ICAM-2 expression by IL-2, both in sparse and dense cultures. These data show that p64/IL-2R gamma expression in human embryonic fibroblasts does not correlate with the ability of the IL-2R to deliver a biological signal.

Amino Acid Sequence↗
PubMed1993

Human melanoma cell line M14 secretes a functional interleukin 2.

Interleukin 2 (IL2) is an important regulator of the immune system. In this report, we have analysed five human melanoma cell lines expressing the IL2R for their ability to secrete IL2. In the M14 melanoma cell line, we observed the appearance of the 0.9 kb transcript specific for the IL2 gene, 72 h after subculture, and the secretion of a biologically active IL2 which specifically sustains the proliferation of the IL2 dependent murine lymphoid cell line CTLL2. In M14 cells, IL2 gene activation is transient as in lymphoid cells but is not inhibited by the immunosuppressive drugs cyclosporine-A and FK506 which are effective on PHA-blasts. In M14 cells, recombinant IL2 (36 pM) induces the down modulation of ICAM-1 expression at the surface of M14 cells. Overnight incubation of these cells with polyclonal anti-IL2 antibodies leads to an increased expression of ICAM-1 and a decreased membrane detection of the IL2R alpha, suggesting the existence of an autocrine/paracrine loop involved in the surface expression of these antigens. A decreased expression of the ICAM-1 protein could help some melanoma cells to escape from cytolytic recognition and therefore favour their metastasis.

Cell Adhesion Molecules↗
PubMed1993

[Gene therapy and cancer: from concepts to clinical applications].

The cure of human cancers at a micro- or macro-metastatic stage of the disease is restricted to chemocurable forms which represent only 10% of all leukemias, lymphomas and solid tumors. Local conditions in the tumor site and biological characteristics of tumor cells are responsible for the resistance to treatment of many malignant tumors. Gene therapy can be applied to locally incurable tumors as well as to systemically disseminated malignancies. Genic "Surgery" can be produced by local intra- or peritumoral injection of viral vectors and/or virus-producing cells. For example in the case of brain tumors the use of retroviruses which are cell-cycle dependent for the injection of target cells is expected to spare the non-cycling normal brain cells from the dividing tumor cells. Three main types of systemic gene therapy are presently under study: a) VDEPT (Virally Directed Enzyme Prodrug Therapy) attempts to induce the production of an enzyme which transforms a prodrug into a cytotoxic drug in the engineered tumor cells. b) Ecotropic genic immunotherapy (tumor-site directed immunotherapy) can be used to produce sufficient local concentrations of cytokines to induce antitumor immune response at the tumor site(s). c) Systemic antigenic gene therapy aims to induce tumor-specific antigens by transfection of tumor cells in order to initiate immune rejection of residual disease by the patient lymphocytic killer cells. The conceptual basis and the limitations of these therapeutic approaches are discussed.

Gene Transfer Techniques↗
PubMed1992

Purification and identification of a CD25 expression inhibitory protein from cell-free supernatants of chronically HIV-infected promonocytic cells.

The CD25 (IL-2-R alpha) cell surface glycoprotein expressed transiently during T-cell activation is implicated in the high affinity IL-2 receptor. This paper shows that cell-free supernatants from chronically HIV-infected promonocytic cells spontaneously produce a soluble factor which inhibits CD25 expression on PHA-activated human PBMC. We purified the CD25 expression inhibitory activity by a factor 12,350, using XM50 ultrafiltration, Superose 12 molecular sieving chromatography and MonoQ anion-exchange chromatography. Then we associated this activity to one single spot (M(r) 29,000, pI 6.8) on an O'Farrell two-dimensional gel. Our data demonstrate that this protein (M(r) 29,000, pI 6.8) is released from HIV-infected promonocytic cells and suggest that this factor is a new monokine regulating the T-cell activation process.

Cell Line↗
PubMed1992

Enhanced hematopoietic growth factor production in an experimental myeloproliferative syndrome.

The murine myeloproliferative syndrome induced by the myeloproliferative sarcoma virus (MPSV) has numerous similarities to human primary myelofibrosis. We have shown that medium conditioned by spleen cells of MPSV-infected mice has the capacity to support the growth of primitive blast cell colonies. The detection of this activity associated with MPSV infection stimulated us to characterize the hematopoietins responsible for this activity. Northern blot analysis showed a large increase, or induction, of interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), macrophage-CSF (CSF-1), and granulocyte-CSF (G-CSF) transcripts in the hematopoietic organs of MPSV-infected mice; however, no IL-3 transcript could be detected in either MPSV-infected or normal mice. Significant levels of IL-1 alpha, IL-6, G-CSF, and CSF-1 bioactivities were found in the serum of MPSV-infected mice, but not in controls. Additionally, analysis of medium conditioned by spleen cells of MPSV-infected mice showed the presence of tumor necrosis factor alpha bioactivity. The increased production of cytokines that are able to stimulate pluripotent hematopoietic stem cells corroborates the hypothesis of a possible involvement of hematopoietic growth factors in the development of some myeloproliferative disorders.

Animals↗
PubMed1992

Inhibition of human immunodeficiency virus (HIV) type 1 multiplication by an avian cellular factor.

A factor secreted from avian cells infected non productively with a non cytopathogenic mutant of vesicular stomatitis virus (VSV ts 1026) interferes with HIV replication in CEM cells and peripheral blood monocytes (PBL). Production of infectious particles is decreased and many virions lack cores and/or spikes. In CEM cells the prmRNA is spliced into 7.5, 4, and 2 kb mRNA. Residual virus contains less env encoded proteins and p 18; p 25 appears as several bands. The processing of tat, rev. and nef proteins differs in treated cells and in controls.

Animals↗
PubMed1992

Abnormal expression of IL-2R beta (p70)-binding polypeptide on HIV-infected patients' cells.

The constitutively expressed IL-2R beta (p70) chain participates in the formation of high-affinity (h.a.) IL-2R and transduces IL-2-mediated signals to normal cells. Its expression on HIV-infected patients' PBMC was evaluated and was found to be decreased in both nonstimulated CD4+ and CD8+ cells. Mitogenic cell stimulation induced IL-2R beta chain expression on both CD4+ and CD8+ cells from asymptomatic and persistent generalized lymphadenopathy patients but not on those from AIDS patients. Comparison of mean fluorescence intensity of IL-2R beta positively stained cells from normals and patients did not reveal significant differences. Cross-linking of 125I-rIL-2 on patients' PHA-blasts revealed decreased signals corresponding to both IL-2-binding chains and, in some cases, neither IL-2R alpha nor IL-2R beta chains could be detected. Decreased expression of IL-2R beta polypeptide was associated with impaired accumulation of the corresponding mRNA transcripts. Binding experiments with 125I-rIL-2 under h.a. conditions showed a decreased number of IL-2-binding sites/cell which was more pronounced in patients with AIDS than in patients with less advanced clinical stages. In vitro HIV infection of normal PHA-blasts also resulted in a decreased number of h.a. IL-2R/cell. High concentrations of rIL-2 in the absence of other mitogenic stimuli induced a decreased cell proliferation and expression of the IL-2R alpha chain and did not enhance the constitutive NK and the generation of LAK activity in several patients, suggesting an impaired IL-2R beta chain-mediated cell activation.

Antibodies, Monoclonal↗
PubMed1992

A phase II study of sequential recombinant interleukin-2 followed by dacarbazine in metastatic melanoma.

16 patients with disseminated malignant melanoma (1 with primary ocular melanoma) entered a multicentre phase II study of recombinant interleukin-2, (rIL-2) given by continuous intravenous infusion on days 1-5 at 18 x 10(6) IU/m2 per day, followed by dacarbazine 850 mg/m2 on day 8. After a 2 week rest, a second course was given. In the absence of disease progression, monthly maintenance cycles were given for up to four cycles. 16 patients received one cycle, 14 received two and 6 patients three or more. All 16 patients are evaluable for toxicity and 15 for response. 2 patients responded (13%). 1 patient with lung and pleural metastases achieved partial remission after two cycles and went off treatment after six cycles. 3 months later a complete response was noted lasting 396+ days. A second patient with lung metastases had a partial response lasting 153 days. 3 patients (20%) had stable disease. Mean rebound lymphocytosis (24-48 h after the end of rIL-2 therapy), cell count 4.9 x 10(9)/l (2.6-8.8 x 10(9)/l) was within the expected limits. Other toxicity was as expected. Thus sequential treatment with rIL-2 and dacarbazine is feasible but synergy did not occur.

Adult↗
PubMed1992

Expression of the interleukin-2 receptor on human fibroblasts and its biological significance.

In this study, we have investigated the expression of the alpha and beta chains of the IL-2 receptor (IL-2R alpha, IL-2R beta) both at the membrane and at transcriptional levels during the lifespan of human embryonic fibroblasts. Here we show that the mAbs IOT14 and MIK beta 1 directed against the IL-2 binding sites of the IL-2R alpha and IL-2R beta respectively, stain human embryonic fibroblasts early in their life span. Data from [125I]rIL2 cross-linking experiments show the simultaneous expression of two IL-2 binding peptides of 70 and 55 kDa respectively on embryonic young fibroblasts as on lymphoid activated cells. The p55 and the p70 IL-2 binding peptides are shown to be specific for the IL-2R alpha and to the IL-2R beta by the finding that these bands are abolished by excess amounts of cold IL-2 and mAbs directed against the IL-2 binding sites of the alpha and beta chains. Scatchard analysis after [125I]IL-2 labelling shows the presence of both high affinity (150 sites with a Kd of 147 pM) and low affinity (1100 sites with a Kd of 4 nM) IL-2 binding sites. Northern blot and dot blot analysis show the presence of specific transcripts for the IL-2R alpha and IL-2R beta genes in early passaged fibroblasts. By contrast, in senescent cultures, only the IL-2R beta transcript were detected. Finally, IL-2 at low concentrations (36 pM) down modulates the level of the intercellular adhesion molecule ICAM-1 in young but not in senescent cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Adhesion Molecules↗
PubMed1992

Phase I trial of recombinant interleukin-2 followed by recombinant tumor necrosis factor in patients with metastatic cancer.

In this Phase I trial, the feasibility of sequential administration of continuous intravenous recombinant interleukin-2 (rIL-2) at 18 x 10(6) IU/m2/day for 6 days, followed by three daily bolus intravenous recombinant tumor necrosis factor (rTNF) infusions at doses escalating between 10 and 120 micrograms/m2/day, was investigated in 31 patients with metastatic malignancies. Prophylactic use of indomethacin prior to and during rTNF administration was found to significantly reduce toxicity. However, despite prophylactic indomethacin, a maximum tolerated dose of rTNF of 120 micrograms/m2 was reached. The limiting toxicity was hypotension. Predictable flu-like toxicities (i.e., fever/chills, hypotension, gastrointestinal toxicity, edema, malaise) were seen in most patients. These started during the rIL-2 infusion and continued during rTNF administration, particularly in the absence of indomethacin. Hematological, renal, and hepatic toxicities were not dose limiting. These toxicities were all reversible after treatment interruption. Pulmonary toxicity [i.e., anaphylactic-like reactions, bronchospasms, and adult respiratory distress syndrome (ARDS)] was seen in several patients immediately after rTNF infusions, irrespective of the rTNF dose or treatment cycle, and mainly in patients with extensive pulmonary metastases. The combined effect of treatment-related ARDS, lung metastases, and a Guillain-Barré syndrome led to the death of one patient. Two partial responses were seen in this study (i.e., breast and renal cancer). Based on these results, a Phase II trial of rIL-2 followed by rTNF has been initiated in metastatic breast cancer patients.

Adolescent↗
PubMed1992

Human immunodeficiency virus-infected adherent cell-derived inhibitory factor (p29) inhibits normal T cell proliferation through decreased expression of high affinity interleukin-2 receptors and production of interleukin-2.

Adherent cells from HIV-infected subjects as well as in vitro HIV-infected normal adherent cells produce spontaneously a 29-kD (p29) factor that inhibits mitogen-induced proliferation of normal T cells. p29 mediates a partial dose-dependent inhibition of total protein synthesis in both nonstimulated and PHA-activated cells that is associated with impaired PHA-induced expression of IL-2 receptor (IL-2R)alpha chain, HLA-class II molecules, and production of IL-2 by these cells; conversely, p29 does not modify the expression of IL-2R beta chain, 4F2, CD9, or transferrin receptor, or the production of IL-1 and TNF alpha by the cells. 1 h preincubation of the cells with p29 is sufficient to detect its biologic activity and added rIL-2 abrogates p29-induced inhibition of IL-2R alpha chain expression; however, p29 does not display any biologic effect on already expressed IL-2R alpha chains. The impaired expression of IL-2R alpha chain mediated by p29 is not due to a decreased accumulation of the corresponding mRNA transcripts, but is associated with a two-fold increase of intracellular cAMP. Binding experiments with 125I-rIL-2 reveals that p29 induces a 50% decrease in the number of both high and low affinity IL-2R per cell. p29 also inhibits alloantigen-induced proliferation of PBMC, whereas it does not modify IL-2-dependent proliferation of 48-h PHA-blasts that already express high affinity IL-2R. These findings indicate that p29 mediates its biologic activity during early stages of T cell activation affecting the expression of high affinity IL-2R and production of IL-2, through a nontranscriptional mechanism involving an increase of intracellular cAMP.

Cyclic AMP↗
PubMed1992

Increased synthesis of extracellular spleen glycosaminoglycans in an experimental myeloproliferative syndrome.

The changes occurring in the hematopoietic extracellular matrix in an experimental myeloproliferative syndrome were explored by comparing the glycosaminoglycan (GAG) composition of normal mouse spleens and spleens infected with myeloproliferative sarcoma virus (MPSV). Large quantities of hyaluronate and of sulfated GAGs accumulated in the extracellular matrix of infected spleens, as shown by histoimmunoassay and alcian blue staining, respectively. The splenic GAGs were either labeled with 35S-sulfate injected in vivo or unlabeled. The spleens were fractionated to separate hematopoietic cells from the stromal component containing extracellular matrix material and fibroblasts, and the GAGs were extracted from each fraction. Specific degradative treatments and electrophoresis indicated that sulfated GAGs were mostly chondroitin sulfate and heparan sulfate. Three hours after in vivo injection of 35S-sulfate, the amount of 35S-GAGs was increased approximately fivefold per mg stromal proteins. The bulk of these 35S-GAGs (70%) was recovered in the stromal fraction. The higher amount of sulfated GAGs in leukemic spleen was due both to the presence of more producer cells (infected fibroblasts and hematopoietic cells) and to a stimulation of GAG synthesis per cell, as evidenced 35S-labeling in in vitro experiments. Chondroitin sulfate was the main sulfated GAG present in the culture medium of both hematopoietic and fibroblastic cells and in the pericellular material released by trypsin from fibroblastic cells. High amounts of chondroitin sulfate, which has a possible role in the detachment of hematopoietic cells from the stromal cells, may favour the release of hematopoietic cells from the spleen into the peripheral blood. Heparan sulfate was produced by fibroblastic cells and it was principally present in their pericellular material. Considering the capacity of heparan sulfate to retain cytokines, as demonstrated by others in vitro, large amounts of heparan sulfate may result in the retention of large amounts of the cytokines, which production is enhanced in the infected spleen. This phenomenon may contribute to promote the hematopoietic stem cell proliferation characteristic of the MPSV-induced myeloproliferative disease.

Animals↗
PubMed1992

Open trial of tacrine therapy in 70 HIV-infected patients.

The purpose of this study consisted in following-up the biological and clinical parameters in HIV infected patients treated with tacrine (THA). THA (150-300 mg/d) was administrated to 70 patients (39 IVC I and 31 IVC II and III). Thirty-five were treated after discontinuation of AZT treatment and 35 as a first intention treatment. Thirty (43%) patients showed an increase in the CD4+ cell count by more than 50% relative to pretreatment levels and fifteen (21%) showed an increase of more than 25%. p24 antigenemia (Ag p24) became negative in eight of the twenty-seven patients who were initially positive, and decreased by 25 and 50% in nine and six patients, respectively. Ag p24 was therefore decreased in 80% of the patients. From a clinical point of view, there were two deaths (3%) and five opportunistic infections (7%). The treatment with THA was stopped in five patients because of side effects (nausea, rash). Neither hepatotoxicity, hematotoxicity, nor pancreatitis was observed during the THA treatment. In group II and III only two patients (6%) developed an opportunistic infection.

AIDS-Related Opportunistic Infections↗