Biomedical subjects

D Olive

Publications and source records attributed to D Olive.

At least 127 records · Page 7Linked to original sources

PubMed1993

Signalling through CD28 T-cell activation pathway involves an inositol phospholipid-specific phospholipase C activity.

Stimulation of the human T-cell line, Jurkat, by a monoclonal antibody (mAb) directed against the CD28 molecule leads to sustained increases in intracellular levels of Ca2+ ([Ca2+]i); the initial rise in Ca2+ comes from internal stores, followed by Ca2+ entry into the cells. The CD28 molecule also appears to activate polyphosphoinositide (InsPL)-specific phospholipase C (PLC) activity in Jurkat cells, as demonstrated by PtdInsP2 breakdown, InsP3 and 1,2-diacylglycerol generation and PtdIns resynthesis. We also observed that interleukin-2 (IL2) production induced via CD28 triggering was sensitive to a selective protein kinase C inhibitor. Of the four other anti-CD28 mAbs (CD28.2, CD28.4, CD28.5, CD28.6) tested, only one (CD28.5) was unable to generate any InsPL-specific PLC or IL2 secretion. However, the cross-linking of cell-bound CD28.5 with anti-mouse Ig antibodies led to an increase in [Ca2+]i. CD28-molecule clustering in itself appears to be a sufficient signal for induction of PLC activity.

Antibodies, Monoclonal↗

PubMed1993

Ig CDR3-like region of the CD4 molecule is involved in HIV-induced syncytia formation but not in viral entry.

The HIV1 envelope glycoprotein gp120 binding site has been previously mapped by genetic studies to the CDR2-like region of the first domain of the CD4 molecule. mAb reactive with epitopes linked to this region (e.g., OKT4A) inhibit both HIV entry into CD4-positive cells and syncytia formation. A second area of this domain, the CDR3-like region, has been shown to be involved in gp120-CD4 interactions, but its role remained so far unclear. We show here that a mAb specific for the CDR3-like region of the CD4 receptor, 13B8-2, actually blocks soluble gp120 binding to CD4, inhibits HIV-induced cell-cell fusion, and prevents viral production by infected cells. However, this mAb fails to inhibit the binding of viral particles to cell-surface CD4 and their entry into CD4-positive cells. These results strongly suggest i) that soluble gp120 and virion-anchored gp120 bind CD4 in distinct manners, ii) that gp120-CD4 interactions required for viral entry and syncytia formation are different, and iii) that mAb binding to the CDR3-like region of the first domain of CD4 affects a post-entry step of the HIV replicative cycle.

Antibodies, Monoclonal↗

PubMed1993

The CD2 and CD28 adhesion molecules induce long-term autocrine proliferation of CD4+ T cells.

In vitro human T lymphocyte activation requires two-signal triggering delivered by lectins, phorbol esters or antibodies directed against surface molecules. Stimulation of adhesion molecules by CD2 and/or CD28 antibodies defines alternative activation pathways. Activation by CD2 + CD28 monoclonal antibodies induces high-level, long-lasting and monocyte-independent proliferation of highly purified T cells. Limiting dilution cultures showed that CD28 in association with CD2 or CD3, without addition of exogenous cytokines, induced single-cell proliferation. CD2 + CD28 stimulation induced long-term interleukin (IL)-2-dependent autocrine proliferation of CD4+ T cell clones. We tried to elucidate this long-term proliferation by evaluating cytokine secretion and cytokine dependency. CD28 associated to CD3 or CD2 induced high levels of IL-2, tumor necrosis factor (TNF) and IL-4 secretion for 10 days, in contrast to CD3 alone which induced only TNF secretion. Cytokines of the monocytic lineage were also secreted, such as colony-stimulating factor-1, granulocyte-macrophage colony-stimulating factor or IL-1, the latter being more specific of CD2 + CD28 activation. Blocking antibodies confirmed the crucial role of IL-2 in CD2 + CD28 activation. Anti-IL-4, anti-IL-7 receptor or anti-TNF antibodies had no effect on proliferation. Stimulation with CD2 + CD28 induced long-term autocrine (at least for IL-2) proliferation for CD4+ T cells, with no evidence for the implication of another cytokine among those tested other than IL-2. This represents a model for long-term autocrine growth for non-leukemic cells.

Antigens, CD↗

PubMed1993

Regulation of CD2-mediated human T cell activation: anti-CD8 monoclonal antibodies inhibit CD2-mediated rise in intracellular calcium.

The human CD8 glycoprotein regulates the function of cytotoxic T cells activated by antigenic peptide as well as via CD3 or CD2 mAbs. Activation of T cells by CD2 mAbs requires two mAbs directed against distinct CD2 epitopes and induces tyrosine phosphorylation, PI-PLC activity generating the second messengers, IP3 and DAG, and finally lymphokine secretion. We have investigated the role of the CD8 alpha molecule in CD2-mediated activation of human cytotoxic T cell clones and CD8+ resting T cells. CD8 alpha-specific mAb inhibited 60% of the allospecific cytotoxicity of the CD8+ clone against its target cell and 86% of the CD2-redirected killing against the HLA Class I-negative Daudi target cell. In addition, CD8 alpha-specific mAb inhibited CD2-mediated TNF alpha and IL2 secretion by the CD8+ clone. Furthermore, CD8 alpha-specific mAb inhibited the increase in intracellular ionized calcium mediated by CD2 mAbs in the CD8+ clone and in purified T cells. Since the [Ca2+]i recruitment from internal stores induced by CD2 mAbs was inhibited, the inhibitory effect induced by the CD8 alpha-specific mAb probably acts on the PI-PLC activation pathway. This inhibition mechanism involves neither a decrease in affinity of CD2 mAb for its target nor a decrease in CD2 cell surface expression or a rise in cAMP known as an inhibitor of the CD2-mediated PI-PLC activity. These results suggest that the inhibitory mechanism induced by the CD8 mAb may prevent the activation of the PI-PLC activity, probably through the CD8 alpha-associated protein tyrosine kinase p56lck.

Antibodies, Monoclonal↗

PubMed1993

A soluble form of the human CD8 alpha chain expressed in the baculovirus system: biochemical characterization and binding to MHC class I.

We have generated a soluble form of the CD8 molecule consisting of the entire extracellular domains of the human alpha chain, by expressing a mutated CD8 alpha cDNA in SF9 cells infected with a recombinant baculovirus. The truncated molecule was secreted into the medium mostly as a disulfide-linked homodimer in which a single cysteine residue in the hinge-like region (Cys143) was sufficient to assure covalent bonding. Soluble CD8 purified to homogeneity appears to be monodisperse as assessed by gel filtration analysis and contains only O-linked carbohydrates. To determine whether recombinant CD8 can interact with MHC class I molecules, we developed an assay that measures binding of MHC class I-bearing cell lines to purified CD8 adsorbed to plastic plates. The level of binding of cells to immobilized CD8 depended on the amount of CD8 bound to the plate and correlated with the levels of cell surface MHC class I expression. The binding was specifically inhibited by monoclonal antibodies directed either against CD8 or MHC class I molecules. This assay therefore provides a way to measure CD8 binding to MHC class I independently of other cell-cell interactions and should allow direct structure-function studies.

Baculoviridae↗

PubMed1993

Anti-T11.1 and -T11.2 monoclonal antibodies play a different role in CD2-mediated signal transduction.

We comparatively evaluated (Ca2+)i mobilization after triggering with a stimulatory pair of CD2 (CD2.9, anti-T11.1 + CD2.1, anti-T11.2) or CD3 mAbs in the differentiated T-cell line Jurkat, using INDO-1 labeling and cytofluorimetry. The results obtained showed different (Ca2+)i mobilization kinetics following CD2 or CD3 stimulation (the former being slower than the latter), not due to different association kinetics of mAbs. In a nonreciprocal manner, however, preliminary interaction with CD2.1 (anti-T11.2) followed by CD2.9 (anti-T11.1) induces a rapid (Ca2+)i rise, similar to CD3 stimulation, as shown by preincubation experiments. There is no interference between CD2.9 and CD2.1 mAb binding. CD2.1 mAb by itself is unable to induce (Ca2+)i mobilization; in addition, preincubation with CD2.1 mAb did not modify the CD2, CD3, CD45, or CD28 immunoprecipitation patterns. Triggering of the epitope recognized by CD2.1 mAb may favor, possibly via conformational changes of CD2 molecule or (Ca2+)i-unrelated metabolic effect(s), optimal signal transduction.

Antibodies, Monoclonal↗

PubMed1993

CD28 mAbs with distinct binding properties differ in their ability to induce T cell activation: analysis of early and late activation events.

A panel of eight different CD28 mAbs was used to analyse the structure-function relationships of the CD28 molecule. The results of binding inhibition experiments show a complex and heterogeneous pattern of inhibition; however a subgroup of mAbs was identified, namely CD28.1, CD28.3, and CD28.5, which exhibited almost identical inhibition profiles. To test the hypothesis that the different binding specificities are related to functionally distinct subregions of the CD28 molecule, the ability of each mAb to (i) induce IL-2 release and (ii) increase intracellular calcium [(Ca2+)i] in Jurkat T cells was analysed. The results show that the mAbs CD28.1, CD28.3, and CD28.5 are almost totally unable to induce IL-2 release, and their ability to increase (Ca2+)i is relatively low. All other mAbs are able to induce a marked (Ca2+)i rise, however they strongly differ in their ability to induce IL-2 release. Such differences cannot be explained by differences in the isotypes or binding kinetics of the mAbs. These results imply the existence of functionally distinct subregions on the CD28 molecule. In addition, the (Ca2+)i rise may be associated with either high or low IL-2 secretion following CD28 triggering.

Animals↗

PubMed1993

Structure, biosynthesis, and transduction properties of the human mu-psi L complex: similar behavior of preB and intermediate preB-B cells in transducing ability.

In human preB cells, the mu chain is associated with a surrogate light chain composed of the VpreB and lambda-like gene products. Using anti-peptide antibodies directed against VpreB and lambda-like epitopes, we identified the discrete components of the mu-psi L (pseudo-light) chain complex in various preB cell lines, and in intermediate preB-B cells that co-expressed the psi L and the kappa chain. The lambda-like gene product was identified as a single band at 20 kDa, disulfide linked to the mu chain. VpreB was detected at 16 kDa and, depending upon the cell lines, an isoform of this polypeptide was also present at 15 kDa. In addition, lambda-like--VpreB chain complexes not associated with mu were identified both in cell lysates and culture supernatants. Pulse-chase experiments indicated that VpreB was transiently associated with two new polypeptides of molecular weights 17.5 and 36 kDa. Expression of mu-psi L and co-expression of mu-psi L and microL at the surface of preB and intermediate preB-B cells respectively was detected by cytofluorimetry. The signal transduction ability of the complex in both types of cells was shown by measuring the calcium mobilization and the phosphorylation of tyrosyl residues upon stimulation by anti-mu. Signal events were similar in both cases, but differed from those induced in a mature B cell line. This points to a definite function of the preB cell receptor and suggests that the intermediate preB-B cell line still lacks some molecular components that condition initiation of a mature B cell transduction signal.

Amino Acid Sequence↗

PubMed1993

Analgesic rebound headache: experience in a community hospital.

In the past, chronic daily headaches have been attributed to many possible causes, including "tension," excessive contraction of pericranial muscles, and depression. A careful history reveals that many patients start out with fairly typical intermittent migraine attacks that evolve over the years into a pattern of daily or almost daily head pain. Overuse of analgesics is usually a part of this clinical picture, which has been termed "analgesic rebound headache." Fifty-three of the first 100 patients admitted to a community hospital's inpatient headache treatment program had chronic daily headaches and were overusing analgesics or other headache relief medications. We report our retrospective review of these patients and describe treatment of this difficult and sometimes unrecognized syndrome, primarily with intravenous dihydroergotamine (DHE). Results at hospital discharge and at follow-up several months later showed significant reduction of pain.

Adult↗

PubMed1993

A tumour-associated antigen expression in human haematological malignancies.

Objective responses obtained with high-dose in vivo recombinant interleukin 2 (r-IL2) in some leukaemic patients suggest among other hypotheses that blasts might express tumour rejection antigens potentially recognized by cytolytic T lymphocytes. Such antigens have been described in human melanomas and the MAGE-1 gene, coding for a tumour rejection antigen was recently identified. This gene is expressed in various solid tumours, but not in normal cells. We have screened a panel of haematological malignancies by reverse transcription and PCR and we report that MAGE-1 is not expressed in the blasts from 48 patients whereas three cell lines derived from leukaemias express this gene.

Antigens, Neoplasm↗

PubMed1993

Incidence rate and risk factors for thyroid dysfunction during recombinant interleukin-2 therapy in advanced malignancies.

Immunotherapy using recombinant interleukin 2 (rIL-2) has been shown to induce thyroid dysfunction in some cancer patients. The purpose of the present study was to evaluate the incidence and risk factors of this adverse autoimmune response. Triiodothyronine, thyroxine and thyrotropin levels were measured serially in 146 consecutive patients treated with rIL-2 for refractory solid tumor (77 patients) or malign hemopathy (69 patients); rIL-2 was administered intravenously in 5-day cycles (18 x 10(6)-24 x 10(6) IU.m-2.day-1) either alone in 79 cases or in combination with autologous bone marrow transplantation in 26 cases, with interferon-gamma in 37 cases, with tumor necrosis factor-alpha in 13 and with cyclophosphamide in five cases. Some patients underwent more than one therapeutic protocol. Peripheral hypothyroidism was present upon entry in nine (6.2%) patients. Thyroid dysfunction appeared or worsened during rIL-2 therapy in 24 (16.4%) patients. Sixteen (10.9%) patients exhibited peripheral hypothyroidism, out of which four exhibited biphasic thyroiditis. Another five (3.4%) patients developed transient hyperthyroidism. Anomaly could not be classified in three patients. Thyroid dysfunction appeared early after one or two cycles. All surviving patients recovered. Only gender and presence of antithyroid antibody were correlated significantly with rIL-2-induced thyroid abnormalities. No correlation was found with any of the other risk factors studied, i.e. type of malignancy, rIL-2 treatment procedure, clinical efficacy, evolution of circulating lymphocyte subsets or other autoimmune antibodies. Antithyroid antibodies were detected in 60.9% of patients with this complication. Thyroid-stimulating antibodies were never detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Interleukin-7 is a potent co-stimulus of the adhesion pathway involving CD2 and CD28 molecules.

Co-stimulation of highly purified peripheral T lymphocytes from healthy blood donors with the adhesion molecules CD2 and CD28 in association with recombinant interleukin-7 (rIL-7) induced T-cell proliferation, multiple cytokine secretion and IL-2 receptivity. We demonstrated that rIL-7 is as potent as rIL-2 in inducing the proliferation of unseparated, CD4+ and CD8+ T cells. In contrast to low or undetectable levels of IL-1 alpha, IL-6 and IL-2, high levels of tumour necrosis factor-alpha (TNF-alpha), IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were secreted. Experiments using blocking antibodies suggested a direct mechanism for rIL-7 co-stimulatory effect, although induction of the CD25/IL-2 receptor alpha-chain (CD25/IL-2R alpha) was observed. Monoclonal antibodies (mAb) against the adhesion molecules CD2 and CD28 are likely to mimic the interaction with their respective physiological ligands [lymphocyte function-associated antigen-3 (LFA-3)/CD58, CD59 and CD48 for CD2, B7/BB1 for CD28]. Taken together, these in vitro data suggest that IL-7 could participate in paracrine interactions between T lymphocytes and thymic stromal cells or dendritic cells, via its potent co-stimulatory activity with CD2 and CD28 adhesion molecules.

Antigens, CD↗

PubMed1993

The role of NF-kappa B1 (p50/p105) gene expression in activation of human blood T-lymphocytes via CD2 and CD28 adhesion molecules.

Stimulation of primary human T-lymphocytes via CD2 and CD28 adhesion molecules induces a long-lasting proliferation (> 3 weeks). This potent activation does not require accessory cells, such as monocytes, but depends on persistent interleukin 2 (IL-2) secretion and receptivity, which is associated with high and prolonged expression of the inducible CD25/IL-2 receptor alpha (IL-2R alpha) chain gene. The transcription factor NF-kappa B participates in the regulation of both IL-2 and IL-2R alpha genes, as well as multiple cellular genes involved in T-cell proliferation. To evaluate the role of NF-kappa B in human peripheral blood T-lymphocytes, we previously analyzed the activation of NF-kappa B-related complexes in response to CD2+CD28 costimulation. We demonstrated a long-term induction of p50/p65 heterodimer, a putative p65/c-Rel heterodimer, and a constitutive nuclear expression of KBF1/p50 homodimers. As the role of p50 remains unclear, we focused our present study on NF-kappa B1 (p50/p105) gene regulation. Using electrophoretic mobility shift assays and Western and Northern blot analyses, we studied NF-kappa B1 gene expression during T-cell stimulation via CD2+CD28. We observed a transient 4- to 5-fold increase of NF-kappa B1 gene expression at both the mRNA and protein levels, lasting for at least 24 h. p50 DNA-binding activity apparently stays highly controlled when p105 expression is enhanced by a physiological stimulus of peripheral blood T-cells. Partial inhibition of p50 and p105 expression by NF-kappa B1 antisense oligonucleotides significantly reduced T-cell proliferation and CD25/IL-2R alpha cell surface expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗

PubMed1993

Activation of primary human T-lymphocytes through CD2 plus CD28 adhesion molecules induces long-term nuclear expression of NF-kappa B.

Stimulation of highly purified human T-cells via CD2 and CD28 adhesion molecules induces and maintains proliferation for more than 3 weeks. This potent interleukin 2 (IL-2)-dependent activation does not require monocytes or accessory cells. Long-lasting IL-2 receptivity is associated with high-level expression of the inducible IL-2 receptor alpha chain (IL-2R alpha) gene that is regulated at both transcriptional and posttranscriptional levels. Increase of IL-2R alpha gene transcription involves the enhanced binding of the transcription factor NF-kappa B to its consensus sequence in the 5'-regulatory region of the IL-2R alpha gene. To dissect the molecular basis for the unusually persistent transcription of the IL-2R alpha gene, we analyzed nuclear NF-kappa B binding to a radiolabeled IL-2R alpha kappa B-specific oligonucleotide probe during the time course of CD2 + CD28 activation. Resting T-cell nuclear extracts contained KBF1/p50 homodimer. After stimulation, two new kappa B-specific complexes were identified as NF-kappa B p50-p65 heterodimer and putative c-Rel homodimer or c-Rel-p65 heterodimer. Both inducible complexes persisted for at least 3 weeks. Their relative levels were very similar for the duration of proliferation. In parallel, CD2 + CD28 activation triggered a significant intracellular thiol decrease, suggesting that oxygen radicals are involved in the signaling pathway of adhesion molecules. Finally, micromolar amounts of pyrrolidine dithiocarbamate, an oxygen radical scavenger that efficiently blocked the nuclear appearance of NF-kappa B in T-lymphocytes, also inhibited IL-2 secretion, IL-2R alpha cell surface expression, and T-cell proliferation. Together, these results suggest that NF-kappa B plays an important role in long-term activation of human primary T-lymphocytes via CD2 + CD28.

Antibodies, Monoclonal↗

PubMed1993

Rationale for the utilization of interleukin-4, an immune-recognition induced cytokine, in cancer immunotherapy.

Interleukin-2 use for advanced cancer treatment has demonstrated that cytokines are of interest not only in the field of immunology but also in oncology. Interleukin-2 is only one member of the ever-growing family of immune recognition-induced lymphokines. Interleukin-4, a cytokine with pleiotropic effects, shares some common properties with interleukin-2. Availability of recombinant interleukin-4 has led to a better knowledge of this cytokine's functions, and also makes clinical trials possible. This brief review discusses the in vitro and in vivo data that support a potential use of interleukin-4 in cancer immunotherapy.

Animals↗

PubMed1993

Therapeutic applications of anti-CD4 antibodies.

The CD4 molecule represents a major functional T-cell surface molecule, defining an important T-cell subset, which also is expressed on monocyte, dendritic, and Langerhans cells. Various in vivo studies have demonstrated its implication in various steps of physiological T-cell activation: 1. CD4 interacts with its physiological ligand, the class II molecules, thus increasing the affinity of the conjugation between CD4+CD(3+)-TCR+ and class II+ antigen-presenting cells. 2. Through CD4, the signal transduction machinery is stimulated via its association with p56lck. In addition, CD4 has proved to be the receptor for gp120, the surface glycoprotein of HIV, that allows the virus to penetrate the CD4+ T cells and monocytes. Based on in vitro studies in various animal models, CD4 mAbs have proved to be efficient in the prevention and/or therapy of a variety of immunologically based diseases: 1. When injected early in the prodromic phase of autoimmune diseases (AID) such as diabetes, either delay or prevention is achieved with or without maintenance after therapy. 2. These mAbs have proved to be self-tolerogenic, thus allowing prolonged in vivo therapy and suppression of immunogenicity of mAb of a distinct specificity. In humans, CD4 mAbs are, or could be, used and evaluated in AID (lupus, diabetes, rheumatoid arthritis, etc.), transplantation, leukemias and lymphomas expressing CD4, and, finally, in AIDS patients, in whom CD4 mAbs can block HIV-CD4 binding and deliver a negative signal to T cell, thus blocking T-cell activation and HIV transcription. CD4 mAbs at least provide evidence that the CD4 molecules are suitable for immunomodulation and could be the target for a new pharmacological antagonist.

Acquired Immunodeficiency Syndrome↗

PubMed1992

Prolonged IL-2 receptor alpha/CD25 expression after T cell activation via the adhesion molecules CD2 and CD28. Demonstration of combined transcriptional and post-transcriptional regulation.

The T cell adhesion molecule CD28 provides a costimulatory signal in combination with CD2 and CD3 mAb. CD28 regulates the expression of cytokines by T cells, not only IL-2, but also IL-1 alpha and CSF-1, usually synthesized by accessory cells. We have investigated the mechanisms through which CD28 modulates the expression of the IL-2R alpha chain. Whereas activation through CD2 or CD28 alone induced no or only low IL-2R alpha chain expression, activation through CD2 plus CD28 led to both a high and prolonged (greater than 14 days) cell surface and mRNA expression. In contrast, immobilized CD3 mAb-dependent activation induced a transient expression of the IL-2R alpha chain, which was neither further increased nor prolonged by CD28 costimulation. Upon CD2 plus CD28 stimulation, the half-lives of the two IL-2R alpha transcripts increased progressively between days 1 and 4, in contrast to each pathway alone. Whereas each activation pathway alone induced either no (CD2) or low (CD28) levels of IL-2R alpha gene transcription, the CD2 plus CD28 stimulation was associated with its increased transcription, which persisted at similar rates between 5 and 96 h post stimulation. The in vitro costimulation via the CD2 and CD28 molecules thus regulates the expression of the IL-2R alpha gene both at the transcriptional and post transcriptional levels. Our results therefore demonstrate a new immunoregulatory function of the CD28 molecule on IL-2R alpha expression, which, through its increased transcription rate and stabilization, could, together with high levels of cytokines secretion, be responsible for the prolonged T cell proliferation.

Antigens, CD↗

PubMed1992

Contributions of the CD2 and CD28 T lymphocyte activation pathways to the regulation of the expression of the colony-stimulating factor (CSF-1) gene.

The T cell adhesion molecule CD28 provides a costimulatory signal, in combination with either CD2 or CD3 mAb. CD28 appears to regulate the expression, by T cells, of cytokines normally produced by accessory cells, namely IL-1 alpha, TNF-alpha, and CSF-1. The CSF-1 gene is expressed as a 4.0-kb transcript by human T cells activated with mAb directed against CD2 and CD28, alone or in combination. A kinetic analysis of its expression showed low steady-state levels of the transcript after CD2 stimulation, and a transient rise after CD28 stimulation. In contrast, a mean fivefold increase in the levels of the transcript was detected in CD2 plus CD28-stimulated cells. The potential mechanisms regulating this increase were investigated. The half-life of the CSF-1 transcript was identical in cells activated with either CD28 or CD2 plus CD28. Transcription of the CSF-1 gene appeared to undergo attenuation in resting cells as well as in cells activated via a single pathway; this attenuation was relieved in part by the combined CD2 plus CD28 stimulation. Thus in vitro costimulation via the CD2 and CD28 molecules regulates the expression of the CSF-1 gene mainly at the transcriptional level.

Antigens, CD↗