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F Sigaux

Publications and source records attributed to F Sigaux.

At least 109 records · Page 6Linked to original sources
PubMed1989

Effect of interferon-alpha on the expression and release of the CD23 molecule in hairy cell leukemia.

Hairy cells are stimulated to DNA synthesis by low molecular weight B cell growth factor (LMW-BCGF) and this proliferative response is suppressed by interferon (IFN)-alpha, both in vitro and in vivo. The suggestion that the CD23 molecule (Fc epsilon II receptor) might be involved in the signalling pathway of LMW-BCGF prompted us to study the expression of this molecule on hairy cells and its modulation by IFN-alpha. By flow cytometry and direct binding experiments with anti CD23 monoclonal antibodies, the presence of the CD23 antigen was detected in 7 of 12 cases tested, on variable percentages of cells, ranging from low to medium expression. In vitro incubation of hairy cells with IFN-alpha, which elicits a suppression of the proliferative response of these cells to LMW-BCGF, induced a parallel significant reduction of CD23 expression in only three cases. Similarly, a transient in vivo decrease of CD23 expression, concommitant with an inhibition of the LMW-BCGF response, could be detected in only one of three patients injected with IFN-alpha. Soluble sCD23/IgE-binding factor (BF) was quantitated in the serum from six other patients with hyperleukocytic hairy cell leukemia (HCL) undergoing a clinical trial of IFN-alpha therapy. Before treatment, these patients presented higher concentrations of the cleaved soluble form of the CD23 molecule than normal controls. Within a few weeks of IFN-alpha administration, these levels markedly decreased, paralleling a diminution of blood leukemic cells. Of interest, no such diminution was noticed for another patient resistant to IFN-alpha therapy. These results show that the proliferative response of hairy cells to LMW-BCGF is not linked to the expression of the CD23 marker. Besides, when the latter molecule was present, its decrease following IFN-alpha treatment, which could be detected in some cases, was not necessarily required for the suppression of the LMW-BCGF response and is thus not mandatory for the therapeutic efficacy of IFN-alpha. Our results point out that quantitation of serum sCD23/IgE-BF, whether related to a process of autocrine proliferation or not, is a parameter of potential importance for therapy monitoring.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1989

Analysis of junctional diversity in the preferential V delta 1-J delta 1 rearrangement of fresh T-acute lymphoblastic leukemia cells by in vitro gene amplification and direct sequencing.

To define the junctional diversity of T-cell antigen receptor delta gene rearrangements in fresh T-acute lymphoblastic cells and to correlate cell phenotype with the coding potential of rearrangements, we determined the junctional nucleotide sequences of 13 T-cell antigen receptor delta gene rearrangements involving the preferentially rearranged V (V delta 1) and J (J delta 1) segments using in vitro gene amplification and direct sequencing. We showed that, as in gamma delta+ cell lines, extensive junctional diversity exists in these clones and that this diversity is due both to random nucleotide deletions/additions and to the use of at least two D delta segments. We also showed that a high percentage of these rearrangements are potentially translatable (7:13) and that such functional rearrangements occur in both surface CD3+ and CD3- cells. Comparison of alpha beta versus gamma delta surface expression demonstrates that all CD3+ T acute lymphoblastic leukemias with a functional V delta 1-J delta 1 rearrangement express a surface gamma delta receptor and are recognized by the anti-delta monoclonal antibody delta TCS1, whereas a control CD3+ gamma delta+ leukemic case that had not undergone V delta 1 rearrangement was delta TCS1-. In addition, expression of this monoclonal antibody is not restricted by V gamma or C gamma usage or by the covalent or noncovalent link between gamma and delta chains.

Amino Acid Sequence↗
PubMed1989

Rearrangements of the T cell receptor delta gene in T acute lymphoblastic leukemia cells are distinct from those occurring in B lineage acute lymphoblastic leukemia and preferentially involve one V delta gene segment.

Rearrangement of the TCR-delta gene was studied using J delta, C delta, and V delta probes in 61 cases of acute lymphoblastic leukemia (ALL) and several cases of chronic lymphoid neoplasms to define the specificity and the diversity of rearrangements occurring at the delta locus. TCR-delta rearrangements or deletions were found in all T (33 cases) and B lineage (28 cases) ALL but not in any case of B cell chronic proliferations (13 cases). The restriction patterns of rearrangement were clearly distinct between T and B ALL and use of one V delta probe showed that rearrangement of the V delta IDP2 gene segment which is also productively rearranged in the Peer cell line, occurred frequently in T-ALL but never in B lineage ALL. Studies of WT31 and delta TCS1 antibody reactivity showed that at least 4 of 13 CD3+ T-ALL cases expressed the delta protein. CD4 and/or CD8 Ag expression were observed in some of the gamma delta expressing T-ALL. These data show that particular TCR-delta gene rearrangements occur in neoplastic early B cells and that the combinatorial diversity of TCR-delta rearrangements in T cells is higher than initially expected. In addition this study shows that an important proportion of CD3 positive T-ALL cases express the gamma delta heterodimer.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Characterization of HTLV-I isolates and T lymphoid cell lines derived from French West Indian patients with tropical spastic paraparesis.

Lymphoid cell lines derived from the peripheral blood of French West Indian patients with HTLV-I sero-positive Tropical Spastic Paraparesis and HTLV-I isolates were characterized. While patients' peripheral blood lymphocytes did not express detectable HTLV-I antigens when uncultured, they did so after short-term culture. Established cell lines were of T-cell lineage: CD2+, CD3+, CD4+, CD7+, WT31+ with activated T-cell markers CD25+, DR+ and a clonal rearrangement of the beta and gamma genes of the T-cell receptor. HTLV-I antigens were detected in cell lines by indirect immunofluorescence, Western blot and radio-immunoprecipitation assays. After 4 months in culture, low levels of Mg2+ dependent reverse transcriptase activity were detected and electron microscopy revealed numerous type-C retroviral particles similar to HTLV-I virions. Western blot and radio-immunoprecipitation analysis of purified viruses revealed gp46, p24, p19 and Pr53gag proteins similar to those detected in HUT 102 and MT2 cell lines. Deep analysis of env-coded precursor of one TSP versus ATL isolates revealed minor differences in their molecular weights. Southern blot analysis using 32P HTLV-I env gene as a probe showed the presence of HTLV-I proviral fragments clonally integrated into the genome of the cell lines. Our data suggest that HTLV-I isolated from Tropical Spastic Paraparesis does not differ significantly from the leukemogenic prototypes. Does HTLV-I induce either acute lymphoproliferative diseases or chronic neuromyelopathies depending upon as yet unknown co-factors? This question remains to be determined.

Blotting, Southern↗
PubMed1989

Rearranging sequence located in the intron of the human T cell receptor gamma chain gene constant region.

Human T cell rearranging gamma genes encode membrane proteins which are expressed by a minor subset of T cells. Extensive studies have shown that TcR gamma gene rearrangements result from V gamma-J gamma recombinations. Here we analyze an unusual rearrangement involving a non-translatable sequence flanked by heptamer and nonamer signals in a Ti alpha/beta-positive T cell clone (JF1). This sequence, designated here as I gamma RS, is distinct from V, D or J elements. It is located in the first intron of the first constant region (C gamma 1) and homologous sequences are conserved in C gamma 2 introns. In JF1 cells the I gamma RS is juxtaposed to the J gamma 2 segment downstream to a V gamma 10-J gamma 1 rearrangement. The use of a cryptic splicing site induced JF1 cells to produce an aberrant large-sized transcript containing the I gamma RS 3' to the first exon of C gamma 1. Such a rearrangement occurring downstream to an inframe V gamma-J gamma junction may induce premature arrest of translation and lack of the C-terminal part of C gamma involved in gamma-protein assembly.

Base Sequence↗
PubMed1989

alpha-IFN treatment does not induce Ki-ras expression in hairy-cell leukemia patients.

alpha-Interferon (IFN) is effective in the treatment of hairy-cell leukemia (HCL), but the treatment is sometimes over a long period. Biological changes such as the increase of tumorigenicity can occur rapidly in vivo as a result of beginning this treatment; an increase in c-Ki-ras oncogene expression has also been observed. In order to determine whether the findings observed in vitro would be duplicated in an in vivo system, we decided to analyze the Ki-ras RNA and protein levels in the lymphocytes of three HCL patients, compared with these levels in seven normal donors and one non-treated HCL patients. Ki-ras was not activated by IFN, at least not in lymphocytes. Therefore, the data suggest that the drug could be used for long-term therapy with relatively low risk to the patients.

Gene Expression Regulation↗
PubMed1989

The human protooncogene product p33pim is expressed during fetal hematopoiesis and in diverse leukemias.

We measured the human pim-1 protooncogene (PIM) expression during fetal development and in hematopoietic malignancies. Our data indicate that during human fetal hematopoiesis the 33-kDa pim product, p33pim, is highly expressed in the liver and spleen. In contrast, at the adult stage it is only slightly expressed in circulating granulocytes. Out of 70 hematopoietic malignancies analyzed, 51 patients and 19 cell lines, p33pim was overexpressed in approximately 30% of the samples, particularly in myeloid and lymphoid acute leukemias. This overexpression was unrelated to any stage of cellular differentiation and was not due to gene rearrangement or amplification. These results imply a physiological role of the pim-1 protooncogene during hematopoietic development and a deregulation in various leukemias.

Adult↗
PubMed1989

Detection of retrovirus particles and reverse transcriptase activity in mid-term cultured peripheral blood and lymph node cells from a French woman with Sezary syndrome.

Retrovirus particles, with an ultrastructure of type C-virus similar to HTLV-I were observed in several mid-term cultures of leukemic cells derived from a woman with a well characterised Sezary syndrome who had always resided in France. Reverse transcriptase activity was detected in supernatant fluids from day 6 to day 40 of culture. However, negative anti HTLV-I serology and the absence of specific molecular hybridization between leukemic cell DNA and two HTLV-I derived probes, argue against a HTLV-I virus.

Aged↗
PubMed1989

In vitro amplification of T cell gamma gene rearrangements: a new tool for the assessment of minimal residual disease in acute lymphoblastic leukemias.

In order to improve the level of sensitivity and specificity of detection of bone marrow minimal residual disease in the acute lymphoid leukemias, we have performed amplification by the polymerase chain reaction of T cell receptor gamma chain gene rearrangements. Cloning and sequencing of amplified leukemic DNA allowed the construction of a clone-specific anti-junctional oligonucleotide to be used for subsequent detection of minimal infiltration by this clone. Using such an oligonucleotide, it was possible to distinguish clonal DNA from polyclonal T lymphocytes and to detect infiltration by this clone at 10(-6) dilution into germline DNA. We therefore describe a generally applicable method for the detection of minimal residual disease in both T-ALL and the majority of B lineage ALLs.

Gene Amplification↗
PubMed1989

The use of clone-specific anti-VJ junction oligonucleotides to identify minor clonal lymphoid populations.

The polymerase chain reaction was used to amplify rearrangements of T-cell receptor gamma genes from 2 leukemic DNA samples involving the same variable segment. One V-J junction was sequenced and an anti-junctional oligonucleotide synthesized. This oligonucleotide was used as probe on in vitro amplified DNA. We show that this strategy allows the detection of the corresponding clonal DNA at dilutions of up to 10(6) fold in germline DNA. Moreover we demonstrate that it is possible to differentiate this clone from the second leukemic clone and from polyclonal T-cells.

Burkitt Lymphoma↗
PubMed1989

Hairy cell leukemia: follow-up after completion of alpha interferon treatment.

Between May 84 and December 85, 61 patients were treated for hairy cell leukemia by (recombinant or natural) alpha-IFN in a single institution. The responses obtained after 7 or 12 months of treatment are presented and the follow-up of the 39 patients for whom the treatment had been stopped for more than 12 months is evaluated. Neither clinical or histological parameters at presentation nor the type of timing of the interferon used allowed to predict the quality of response. The median time-lapse before the occurrence of neutropenia below 1.10(9)/l in patients with normal blood counts at the end of treatment was 12 months. However early relapses after the treatment stop were observed more frequently in patients with initially severe neutropenia or hyperleucocytosis. The therapeutic strategy in hairy cell leukemia is discussed.

Female↗
PubMed1989

Expression of the B8.7 antigen on hairy cells and relation with the LMW-BCGF response.

Hairy cells are classified as B cell tumors at a preplasma cell stage of differentiation and are believed to represent cells undergoing a switch process. These cells are stimulated in vitro to DNA synthesis and multiplication in the presence of the lymphokine LMW-BCGF. We have tested the level of expression on these cells of the newly described B8.7 activation marker which has been reported to be associated with the capacity of various B cells to respond to LMW-BCGF. The presence of this marker has been readily detected on the hairy cells of 10 of the 12 patients tested in this study; interestingly, for one of the negative cases, the tumor cells were unable to proliferate in response to LMW-BCGF. As on normal B cells, a marked inhibition of the LMW-BCGF dependent response could be achieved in the presence of a monoclonal anti-B8.7 antibody, sustaining the proposal that the B8.7 molecule is involved in the signaling pathway of this growth factor. IFN-alpha is highly efficient in the therapy of hairy cell leukemia (HCL), and we confirm in the present study that IFN-alpha also inhibits the LMW-BCGF dependent proliferation of hairy cells in vitro. In addition, we show that this inhibition is independent of a significant modulation of the B8.7 antigen, a molecule putatively associated with the LMW-BCGF receptor.

Adult↗
PubMed1989

Are most secondary acute lymphoblastic leukemias mixed acute leukemias?

A case of acute lymphoblastic leukemia (ALL) secondary to X-ray exposure is reported. The lymphoblasts expressed T-cell and myelomonocytic differentiation-related surface antigens. Clonal chromosomal abnormalities including t(2;12)(q25;q13),-10,der(10), del(11)(q14),der(12) and r were observed. A review of the cytogenetic data suggests that most secondary ALLs, with the exception of Burkitt type ALLs, may be biphenotypic or mixed acute leukemias.

Adult↗
PubMed1988

The V gamma locus of the human T cell receptor gamma gene. Repertoire polymorphism of the first variable gene segment subgroup.

Southern blot analysis using a genomic probe of the human TCR-gamma chain first variable gene subgroup (V gamma I) was performed on DNA samples from both parents of 36 healthy Caucasian families. Two types of polymorphisms were found in these 72 unrelated DNA samples: three repertoire polymorphisms and two restriction fragment length polymorphisms (RFLP). In all cases, Mendelian inheritance of these polymorphisms was demonstrated. The most frequent repertoire polymorphism consists in the lack of the V gamma 4 and V gamma 5 segments. In 16% of chromosomes, the Eco RI and Taq I restriction fragments corresponding to V gamma 4 and V gamma 5 were lacking, with no additional bands. In these cases, a decrease of 10 kb was observed in the Bam HI fragment containing all V gamma I segments as compared with samples containing V gamma 4-V gamma 5 segments. To better understand this polymorphism, which takes place in a previously incompletely defined region, the central part of the V gamma I region, including the polymorphic V gamma 4-V gamma 5 segments, was cloned. This allowed us to localize precisely the V gamma 5 segment and thus complete the description of the V gamma I region. A striking homology of DNA and deduced amino acid sequences is present between V gamma 2 and V gamma 4 and between V gamma 3 and V gamma 5, much higher than that observed between V gamma 2 and V gamma 3 and between V gamma 4 and V gamma 5. The differences in nucleotide sequence occur mainly in the intron and three hypervariable regions. These results strongly suggest a gene duplication relationship between the segments V gamma 2-V gamma 3 and the segments V gamma 4-V gamma 5. The most frequent RFLP documented in this study is due to the combined absence of the Eco RI and the Taq I sites located in the noncoding region between V gamma 3 and V gamma 4. The haplotypic frequence of this RFLP is 6.9% of the general population. As the gamma/delta receptor may play an important role in immunological response, the biological relevance of the high degree of polymorphism occurring in the V gamma I region, as well as its possible association with some immune disturbances, should be further explored.

Amino Acid Sequence↗
PubMed1988

Action of interferon-alpha on hairy cell leukemia: expression of specific receptors and (2'-5')oligo (A) synthetase in tumor cells from sensitive and resistant patients.

IFN-alpha induces tumor regression with a high percentage of complete remissions in hairy cell leukemia. We have recently reported that hairy cells express specific IFN-alpha receptors which are down-regulated upon therapy. We show here that the activity of 2-5 A synthetase, an IFN-induced enzyme, is 2 to 7-fold stimulated in hairy cells from responsive patients within 12-24 h after the first IFN dose. This in-vivo enzyme induction paralleled the kinetics of receptor down-regulation. In one patient who was unresponsive to IFN-alpha treatment neither expression of IFN-alpha receptor nor change in 2-5 A synthetase were expressed and modulated as in sensitive patients. In-vitro treatment of hairy cells with recombinant interferons showed that IFN-beta 1 was able to induce this enzyme to the same extent than IFN-alpha 2, whereas IFN-gamma was inactive despite the presence of specific IFN-gamma receptors. Our results indicate that IFN-alpha can exert its therapeutic effects by acting directly on the hairy cells through interaction with surface membrane receptors. Induction of 2-5 A synthetase can be one of the steps involved in this action. However, both mechanisms, as well as receptor down-regulation are not sufficient to explain the responsiveness of hairy cell leukemia to IFN-alpha.

2',5'-Oligoadenylate Synthetase↗
PubMed1988

Expression of the T cell gamma gene by a functionally defined human T cell clone. Characterization at DNA, RNA, and cell membrane level.

In the present study we describe one CD2+CD3+ clone termed DS6 which expressed neither CD4 nor CD8 differentiation antigens and failed to react with WT31, a monoclonal antibody directed against the T cell antigen receptor alpha/beta heterodimer. This clone was isolated from peripheral blood T lymphocytes of a patient with a prolonged immunodeficiency after allogeneic bone marrow transplantation. Normal-sized T cell gamma gene transcripts were detected in DS6 by northern analysis, whereas no mature beta or alpha chain mRNA were found. The rearrangement of TCR beta chain genes and T cell gamma genes was analysed. While in DS6, TCR beta chain genes remain in germinal configuration, and a unique pattern of monoallelic T cell gamma gene rearrangement was observed. The rearrangement involves the recently described V gamma 5 segment and the J gamma 1 joining segment, which is located upstream of the C gamma 1 constant region. To determine the molecular structure present on DS6, an immunoprecipitation was performed with monoclonal anti-CD3 antibody and a rabbit antiserum raised against gamma protein. We have observed, in association with the CD3 complex, a 90 kDa structure which under reducing conditions resolves into three subunits of 45, 40 and 37 kDa. We demonstrated that the rabbit anti-gamma serum only immunoprecipitates the two lower bands. The upper band corresponds to a presently undefined T cell receptor chain. Next, we showed the non major histocompatibility complex (MHC)-restricted cytolytic activity exhibited by these CD3+CD4-CD8- cloned T cells and inhibition of the natural killer (NK)-like activity by the anti-CD3 monoclonal antibody. The triggering of CD2 or CD3 molecules increased IL-2 receptor expression on DS6 but failed to induce cell proliferation. This contrasts with recent results obtained with gamma-expressing T cell clones and illustrates the functional heterogeneity of the cells bearing the second T cell receptor.

Antigens, Differentiation, T-Lymphocyte↗