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M Vuillaume

Publications and source records attributed to M Vuillaume.

At least 37 records · Page 2Linked to original sources
PubMed1993

Expression of the Epstein-Barr virus (EBV) latent membrane protein is tightly regulated, independently of EB nuclear antigen 2 and of EBV integration or copy number.

In vivo, Epstein-Barr virus (EBV) is associated with human tumours and with lymphoproliferations in immunosuppressed patients. In vitro, EBV induces unlimited growth of normal B-lymphocytes, a phenomenon known as immortalization. A limited number of viral genes is expressed during this phenomenon and their relative role concerning the deregulation of cellular proliferation is still unclear. At present, the nuclear antigen EBNA2 and the membrane protein LMP are the two EBV proteins considered to be implicated in the immortalization process. Moreover, many data support the hypothesis that EBNA2 is the major inducer of LMP expression by transactivation; however, in some instances, expression of the two proteins is not correlated, suggesting the existence of complex interactions between EBV and its host-cell that influence viral gene regulation. In an attempt to study thoroughly these EBNA2/LMP interactions, it is important to evaluate whether EBNA2 is or is not a major inducer of LMP expression, and which other parameters can influence LMP expression. By analysing two sets of B-lymphoma lines either infected in vitro with EBV or stably transfected with EBNA2, we have demonstrated that (1) LMP expression can be absolutely independent of EBNA2 expression, (2) the level of LMP expression is very tightly regulated, and is independent of EBV genome status (integrated or episomal) and copy number. Our findings provide compelling evidence that LMP expression has to be related to that of cellular factors that remain to be identified.

Antigens, Viral↗
PubMed1993

Decrease in catalase activity and loss of the 11p chromosome arm in the course of SV40 transformation of human fibroblasts.

The activity of catalase, a key enzyme in cell detoxication of oxygen derivatives, was studied in SV40 transformed human fibroblasts. A cytogenetic study was performed in parallel to establish a quantification of 11p arm on which the corresponding gene is mapped. mRNA amounts were determined by Northern blotting. At early passages, catalase activity strongly decreased whereas the corresponding mRNA was present. No deletions of 11p arms were detected. At later passages, catalase activity remained low. 11p arm deletions were frequent, and the amount of mRNA was decreased. In these late passages, the good correlation between the number of 11p arms and catalase activity suggested a gene dosage effect. It is assumed that the decrease of catalase activity provides a selective advantage for the transformed cells. This decrease is related to a post-transcriptional change of regulation at early passages and to the loss of the corresponding gene at later passages.

Catalase↗
PubMed1992

Striking differences in cellular catalase activity between two DNA repair-deficient diseases: xeroderma pigmentosum and trichothiodystrophy.

Xeroderma pigmentosum (XP) and trichothiodystrophy (TTD) are two recessively transmitted human diseases characterized by DNA repair deficiency. While XP is associated with a very high incidence of cancer on skin exposed to sunlight, TTD is not a cancer-prone disease. Therefore, unrepaired UV-induced DNA lesions do not appear to be enough to give rise to tumors. In order to understand the differences between these two syndromes, we measured catalase activity in cellular extracts, UV irradiated or not, and quantified H2O2 production following in vitro UV irradiation. We confirmed on 21 different XP diploid fibroblast lines that catalase activity was decreased on average by a factor of five as compared to controls, while XP heterozygote lines exhibited intermediary responses. All seven TTD lines we tested were deficient in UV-induced lesion repair and exhibited a high level of catalase activity. However, molecular analysis of catalase transcription showed no difference between normal, XP and TTD cell lines. This was confirmed by Western blots where the amount of catalase subunits was identical in all cell lines studied. Finally, UV irradiation induces five and three times more H2O2 production in XP lines compared with TTD or controls respectively. These striking differences between TTD and XP indicate that UV light, directly or indirectly, together with defective oxidative metabolism may increase the initiation and/or the progression steps in the XP environment compared to TTD. This may partly explain the different tumoral phenotype observed between the two diseases.

Acatalasia↗
PubMed1991

Catalase-associated abnormalities and H2O2 increase in pre-neoplastic and neoplastic lesions of the human lower female genital tract and their near adjacent epithelia.

We report that an internal and non-UV-dependent type of neoplasia, the human cervical intraepithelial neoplasia (SIL), is also deficient in catalase activity, like the UV-induced tumors in the autosomal recessive human epithelial disease, xeroderma pigmentosum (XP). Whether or not the lesions are papillomavirus (HPV) positive in the different categories of preneoplastic and neoplastic extracts, the following parameters are affected: i), catalase activity level; ii), kinetic profile of catalase activity; iii), H2O2 increase. Mathematical treatment of these parameters (CONSTEL-Program), unambiguously distinguishes between normal and pathological cases. Such analyses make it possible to grade the pathological samples into 4 classes, depending on their deviance from normality. These classes may be correlated with the gradual steps in the process of malignant transformation defined by histological and clinical diagnosis. We found conformity between catalase activity and histological analyses in 66 biopsies, out of a total of 100 biopsies (35 patients). Moreover, 23 patients presenting decreased catalase activities in 31 biopsies showed disease progression after 3 to 6 months contrary to surgery histological data. We show that ATP synthesis in the presence of catalase and H2O2 (further aspect of catalase function), may occur in neoplastic extracts at much lower concentrations of H2O2 than in normal extracts. Thus, the catalase abnormality seems to be a good tool to study pre-neoplastic to neoplastic evolution of lesions and their adjacent tissues of the lower female genital tract; furthermore, i) it provides an earlier, more powerful means of detecting micro-SIL in progression to squamous cell carcinoma, than combined clinical and histological examinations; ii) model for investigating drugs such as in situ H2O2 scavengers or agents increasing glutathione peroxidase activity (GSH).

Adult↗
PubMed1990

Antioxidant activity of hemocyanin; a pulse radiolysis study.

In order to determine the reactivity on hemocyanin from Androctonus australis, the reaction of superoxide anion has been investigated using pulse radiolysis. The kinetics of O2- decays have been studied in aqueous buffered media at various basic pH (8, 8.5 and 9), first in the absence and then in the presence of hemocyanin (in oxygenated solutions containing formate anion 0.16 mol.l-1). We have shown that, in the presence of hemocyanin, O2- decay is a first-order process whose apparent rate constant is proportional to protein concentration (10(-7) to 10(-6) mol.l-1) and pH independent between 8 to 9. A second-order rate constant of 3.5 +/- 0.1.10(7) mol-1.l.s-1, has been deduced for the catalytic rate constant of hemocyanin with O2-. Meanwhile, this activity is smaller than that described for free copper, eukaryotic Cu-Zn-SOD or some copper chelates. We have verified that apohemocyanin--the copper deprived protein--does not exhibit such an activity vs. SOD (superoxide dismutase).

Animals↗
PubMed1990

Deficiency in catalase activity correlates with the appearance of tumor phenotype in human keratinocytes.

Biopsies isolated from various human stratified epitheliomas and cultures of the associated fibroblasts exhibit a breakdown in catalase activity (70 to 95%). We report here that primary human cultures of keratinocytes and various immortalized keratinocyte cell lines differ from one other in their catalase activity. Moreover, deficient catalase activity appears to be related to the intensity of tumor phenotype expression. Since catalase activity in cell lines transformed in vitro is not as weak as activity observed in cell lines isolated from tumors, catalase deficiency may follow the successive steps of tumor progression.

Acatalasia↗
PubMed1989

Stimulated production of ATP by H2O2 disproportionation in extracts from normal and xeroderma pigmentosum skins, and from normal, xeroderma pigmentosum, ataxia telangiectasia and simian virus 40 transformed cell lines.

It has been previously shown that xeroderma pigmentosum (XP) skin biopsies and their established cell lines exhibit a decrease in catalase activity and enhanced formation of photo-produced H2O2. Several in vivo and in vitro thermodynamic results suggest that the energy of H2O2 disproportionation produced by catalase could be sufficient to synthesize ATP with or without the help of intact mitochondria. In this paper, we first studied the properties of H2O2-stimulated ATP production in extracts of normal and pathological XP skin biopsies and cell lines. In acellular extracts of normal skin biopsies and/or cell lines, ATP production can be increased 2- to 3-fold, but only with a narrow range of H2O2 concentration. In contrast, in extracts of pathological skins or cells, ATP production was only observed when using 10- to 1000-fold less H2O2 concentration as defined for normal extracts. Similar results were noted with two cell lines derived from patients afflicted with ataxia telangiectasia (AT), and with simian virus 40 (SV40) transformed lines of normal, XP and AT cells, Although we have no proof that such a process may exist in vivo, we would like to suggest that both H2O2-stimulated ATP production and catalase activity are good indicators of the degree of normality or abnormality of skin biopsies and/or cell lines.

Adenosine Triphosphate↗
PubMed1989

Epstein-Barr virus associated lymphoproliferative diseases (B cell lymphoma) after transplantation.

We report 12 cases of lymphomas which occurred among 1670 patients with kidney or combined renal and pancreatic transplantation. Group 1 comprised nine patients presenting with the diffuse form of the disease where immunoblasts or mature plasma cells massively infiltrated all organs. The first symptom was a viral syndrome, associated with a restriction of heterogeneity of immunoglobulins; oligoclonal to monoclonal peaks of immunoglobulins appeared about 50 days after transplantation. All patients received antilymphocyte globulins (ALG), and seven were treated with cyclosporin. EBV infection could be demonstrated in almost all patients; three EBV lymphoblastoid cell lines were established, their HLA phenotype being the same as the recipient of the graft. All patients finally died with renal and hepatic failure. Group 2 comprises three patients who presented solid B cell tumours of tonsils, lungs, and spleen at onset, extending to liver, kidney graft, lymph nodes, and brain. All received cyclosporin; two patients were treated with ALG, and one with OKT3. Immunoglobulins were polyclonal, oligoclonal, or decreased. Cell surface immunoglobulins were monoclonal on two tumours. EBV-DNA was positive within two tumours. Two patients presented EBV and CMV primary infection. CD4+T lymphocytes subsets were diminished at onset, and increased after cessation of immunosuppressive therapy. One patient died because of brain involvement; the two others are alive, one with perfect graft function. Therapy consisted of stopping immunosuppressive treatment, Acyclovir, and in two patients of group 2, monoclonal antibodies to pan-B and EBV receptor antigens.

Acyclovir↗
PubMed1987

Epstein-Barr virus (EBV) induces expression of B-cell activation markers on in vitro infection of EBV-negative B-lymphoma cells.

A set of B-cell activation markers, including the EBV/C3d receptor [complement receptor type 2 (CR2) (CD21)], the 45-kDa lymphoblastoid cell-associated (Blast-2) antigen (CD23), and the B-cell restricted activation (Bac-1) antigen (which was recently identified as a potential B-cell growth factor receptor) can be turned on by infecting lymphoma cells that are genome negative for Epstein-Barr virus (EBV) with the B95-8 immortalizing strain of the virus. The nonimmortalizing EBV variant, strain P3HR-1, which possesses a deletion within the BamHI WYH region of the genome containing the coding sequence for the EBV-determined nuclear antigen 2, does not induce expression of these markers. Other lymphoblastoid cell-associated antigen markers can be activated by infection with either immortalizing or nonimmortalizing viruses. These results suggest that the immortalizing potential of EBV is correlated with its ability to induce expression of B-cell activation markers, which are suspected to play a major role in the physiological pathway leading to lymphoid cell proliferation. The viral genomic region deleted in the nonimmortalizing strain of EBV seems to be required for activation of some of these markers. Human lymphoma cell lines, such as those used in this study, can thus help identify the specific EBV genes involved in lymphoid B-cell proliferation and the mechanism of action of these genes.

Antigens, Neoplasm↗
PubMed1987

Biochemical and ultrastructural findings in Epstein-Barr virus-transformed lymphoid cell lines from type 1 Gaucher disease.

Lymphoid cell lines established by Epstein-Barr Virus (EBV)-transformation of peripheral blood B-lymphocytes from patients affected with type 1 Gaucher disease showed a severe deficiency of glucosylceramide-beta-glucosidase activity (residual activity around 15%-30% of control activity). Ultrastructural investigations showed, in these lymphoid cell lines from type 1 Gaucher disease, the presence of numerous membrane-bound inclusion bodies characteristic of Gaucher cells.

Adult↗
PubMed1987

B-cell maturation stages of Burkitt's lymphoma cell lines according to Epstein-Barr virus status and type of chromosome translocation.

This study addressed the possible relationship between B-cell maturation stage of Burkitt's lymphoma (BL) cell lines and Epstein-Barr virus (EBV) status, ethnic group, or type of chromosome translocation. Fifty-seven cell lines obtained at the International Agency for Research on Cancer from 51 patients were studied. Cytogenetic analyses of 54 cells lines were available. Cell size, surface immunoglobulins (sIgs), cytoplasmic immunoglobulins (cIgs), mouse red blood cell receptors, and reactivity with various monoclonal antibodies were assessed. Immunoglobulin (Ig) class secretions were measured in the supernatant of 2- and 5-day cultures from 33 cell lines, with the use of a sensitive enzyme-linked immunosorbent assay technique. From this study, BL appears to cover a broad range of the B-cell differentiation sequence, since the following Ig phenotypes were observed: null cells (sIg-, cIg-), large pre-B-cells (intracytoplasmic mu-chains), small B-cells (sIg+, cIg-), and various types of secreting B-cells (sIg+, cIg+). Among the latter, various patterns of cIg could be defined (perinuclear, paranuclear, and vesicular). B-cell maturation stages were correlated with the amount of secreted Ig. In sIg+ cell lines, different classes of Ig were found: 35 IgM, 10 IgM plus IgD, 4 IgG, and 1 IgA. None of the different monoclonal antibodies used was specific to a precise stage of maturation. The stages of maturation were correlated with neither the type of chromosome translocations of BL nor the presence of EBV genome, but the most immature cell lines were all EBV positive and most of them originated from African patients. In contrast with acute lymphoblastic leukemia, the common acute lymphocytic leukemia antigen (CD10) was expressed on nearly all BL cell lines of intermediate maturation stages but only on half of the pre-B ones. In addition, none of the cell lines tested was found to react with CD5 antibodies, which recognize most of the chronic lymphocytic leukemia of the same stage of maturation as that in the B-lymphocyte lineage.

Adolescent↗
PubMed1986

Geographical prevalence of two types of Epstein-Barr virus.

The Jijoye EBV strain is characterized by a substitution of 1.8 kb in the C-terminal part of the EBNA 2 gene compared to B95-8 or M-ABA virus. This made it possible to construct hybridization probes specific for M-ABA (type A) and Jijoye viruses (type B), which have been used to type the EBV genomes in 38 spontaneously established cell lines. Type A is more prevalent being found in 31 of 38 cases; type B virus was found in five cell lines (Jijoye, LY 67, QIMR-GOR, BL 16, and BL 29); and two cell lines, Daudi and EB-3, contained neither the M-ABA- nor the Jijoye-specific sequences. EBV type B appears to be less ubiquitous, since all type B isolates, including AG 876 virus, originated from Central Africa, La Réunion, and New Guinea. All the other cell lines, carrying EBV type A, were established from patients from Central Africa (4), North Africa (7), New Guinea (1), and Asia (6) and from white individuals (13). The restricted geographical localization of EBV type B in parts of the southern hemisphere and its similarity to herpesvirus papio (T. Dambaugh, K. Hennessy, L. Chamnankit, and E. Kieff (1984) Proc. Natl. Acad. Sci. USA 81, 7632-7636) could suggest that such viruses may have evolved by recombination of EBV with a related Old World monkey virus, alternatively, evolution of virus variants within the human species also being conceivable.

Cloning, Molecular↗
PubMed1986

Deficiency in the catalase activity of xeroderma pigmentosum cell and simian virus 40-transformed human cell extracts.

It has been previously shown that skin biopsies isolated from various xeroderma pigmentosum (XP) patients present a permanent decline in catalase activity from the onset of the disease to the tumor formation. We report here that cultured XP cell strains are also markedly deficient in the catalase activity with about only 25% of the activity measured in normal human cells. No direct correlation between catalatic activity and excision repair ability has been found, since a XP variant line is as deficient as an XP-C strain. The exact cause of the catalase deficiency is still unknown but could be due to the synthesis of a modified enzyme or to an abnormal regulation leading to a limited enzyme synthesis. Furthermore, simian virus 40 transformation of normal and radiosensitive cells (XP, ataxia telangiectasia) provokes a decrease in catalase activity of about 80% compared to the control derivatives. Mathematical analysis performed on our data shows a clearcut distinction between XP and normal cells while some of the XP heterozygote cells exhibit an intermediate behavior. Although most of the XP syndrome could be explained by the impairment in the excision repair ability, the decrease in catalase activity leading to a probable increase in intracellular H2O2 concentration and/or to a higher sensitivity to any oxygen-activated species could represent an additive effect in inducing the carcinogenic process.

Acatalasia↗
PubMed1985

Validity of lymphoid cell line for enzymatic studies of GM2-gangliosidosis variant 0 (Sandhoff disease).

A lymphoid cell line established by Epstein-Barr virus (EBV)-transformation of peripheral blood B-lymphocytes from a patient with Sandhoff disease showed a severe deficiency of beta-N-acetylhexosaminidase activity (residual activity around 10% of that in lymphoid cell lines from normals or other lipidotic patients). This residual beta-N-acetylhexosaminidase was completely heat-labile in contrast to that of normals. The molecular forms of residual beta-N-acetylhexosaminidase from Sandhoff lymphoid cell line were separated by Con A-sepharose and electrofocusing. Their properties and electrofocusing profiles were compared to those from Sandhoff fibroblasts and from fetal brain: this comparison permitted to identify the residual molecular forms with Hex S and Hex C. The microheterogeneity of Hex S and Hex C, demonstrated by electrofocusing, was discussed. 2-Acetamido-2-deoxy-D-galactonolactone (GalNAcLone) showed a strong inhibitory effect on lysosomal Hex A, B and S, but only a very slight effect on Hex C. Studies of the inhibition type (competitive on Hex A, B and S and mixed on Hex C) gave some informations about the enzymatic site. Elsewhere, differences in affinity of GalNAcLone for the various isoenzymes could be utilized to define optimal assay conditions for specifically determining Hex C (standard assay containing 400 mumol/l of GalNAcLone). These results demonstrated that EBV-transformed lymphoid cell lines represent an accurate model system for enzymatic studies of Sandhoff disease.

Acetylgalactosamine↗
PubMed1985

The use of lymphomatous and lymphoblastoid cell lines in the study of Burkitt's lymphoma.

To better characterize the virological and cytogenetic features of Burkitt's lymphoma (BL) occurring in so-called low-incidence areas, biopsy specimens were collected from BL patients diagnosed and treated in France, and attempts were made to cultivate malignant cells in vitro in order to provide large amounts of tumour material for further laboratory investigations. Sixty new BL-derived lymphomatous cell lines have been established from 43 individuals: 24 Caucasians, 14 North Africans and five Africans. Of these, 27 lines (from 18 individuals) were established from non-Epstein-Barr virus (EBV)-associated BL tumours, indicating that the relative ease in cultivating BL malignant cells in vitro is not limited to EBV genome-containing BL tumours. Cytogenetic investigations showed that all the BL cell lines had one of the three 'BL translocations' - t(8;14), t(8;22) or t(2;8). An estimate of the frequency of each translocation, based on the analysis of 51 independent IARC BL cell lines gave the following results: t(8;14), 76%; t(8;22), 16%; t(2;8), 8%. This large panel of cell lines is now a valuable tool for analysing the various phenotypic characteristics of BL cells. Comparisons can be made between multiple lines of BL from high-, intermediate- and low-incidence areas; significant numbers of EBV genome-negative and -positive lines and of tumour cells taken at diagnosis and at various stages of the disease can also be compared. For molecular and immunological investigations, EBV-immortalized lymphoblastoid cell lines (LCL) were also established from non-malignant lymphocytes of BL patients. The 24 paired BL and LCL cell lines obtained so far will allow precise, controlled studies of the molecular consequences of chromosomal translocations and of the comparative susceptibility of BL and LCL to immune effectors.

Adolescent↗
PubMed1984

Acid lipase and carboxylesterases in EBV-transformed lymphoid cell line from Wolman's disease: influence of fatty acid structure of substrate.

Lymphoid cell lines established by Epstein-Barr virus transformation of blood B lymphocytes from a patient with Wolman's disease exhibited the acid lipase deficiency characteristic for this disease. Comparison of hydrolysis by normal and Wolman's cells of 4-methylumbelliferyl-acyl esters with variable chain length demonstrates that: (1) the best substrates for acid lipase were characterized by an acyl chain length of 12-18 carbon atoms; (2) the acid residual activity in Wolman's cells showed a slightly different substrate specificity and this is probably due to an acid carboxylesterase different from the lysosomal acid lipase, and (3) the 'nonspecific' carboxylesterases (at pH 6.0 and 8.0) not inhibited by taurocholate showed a characteristic substrate specificity for short-chain fatty acids. In the used assay conditions (optimal for acid lipase), methylumbelliferyl-palmitate, -elaidate and -lignocerate are the most accurate synthetic substrates for the diagnostic of Wolman's disease.

Carboxylic Ester Hydrolases↗
PubMed1984

Establishment of lymphomatous cell lines from bone marrow samples from patients with Burkitt's lymphoma.

A total of 233 bone marrow aspirates were obtained from 43 patients with Burkitt's lymphoma (BL). Lymphoma cells were absent and lymphoblastoid cell lines could not be established from 197 samples, which were characterized by limited initial cell proliferation and development of an adherent population, followed by cell death after 2-4 weeks. In 14 aspirates, after a similar pattern of growth, cell proliferation began again after about 6 weeks, with a rapid appearance and growth of cell clumps from the feeder layer--a type of growth typical of spontaneous lymphoblastoid cell lines. In 22 aspirates, growth of malignant cells was observed in culture and cytocentrifuged, stained smears, including marrow samples from 9 patients in whom the presence of BL cells had not been ascertained or even suspected by cytology. Karyotypic anomalies characteristic of BL were found in these cells: t(8;14) in the majority, two t(8;22), two t(2;8), and one t(2;8;9).

Adolescent↗