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J De Maeyer-Guignard

Publications and source records attributed to J De Maeyer-Guignard.

At least 19 recordsLinked to original sources
PubMed1998

Type I interferons.

Type I interferons (IFNs) constitute a family of structurally related proteins that are all derived from the same ancestral gene and act on a common cell-surface receptor. Contrary to many other cytokines, the production of type I IFNs is not a specialized function, and all cells in the organism can produce them, usually as a result of induction by viruses, via the formation of double-stranded RNA. Type I IFNs are indeed responsible for the first line of defense during virus infection and act through the induction of a great number of proteins. Of these, at least thirty have been characterized, and there are probably many more. In addition to their direct antiviral effect, type I IFNs exert a wide variety of other activities, such as for example the induction of various cytokines and the stimulation of different effector cells of the immune system. Due to these pleiotropic effects, recombinant interferons are used in the clinic to treat a variety of diseases, among which cancer, viral hepatitis and multiple sclerosis.

Animals↗
PubMed1994

Stable antiviral expression (SAVE) as an approach to somatic cell gene therapy directed against HIV infection.

We are developing methods for somatic cell gene therapy directed against infection with human immunodeficiency virus by enhancing the antiviral resistance of target cells through the constitutive production of interferon-beta. Cells that have been transformed by plasmids or retroviral vectors carrying the human interferon-beta gene placed under the expression control of a murine H2Kb promoter fragment become resistant to HIV infection. Part of this enhanced resistance is due to inhibition of virus entry into the transformed cells, a hitherto unreported mechanism of interferon action.

3T3 Cells↗
PubMed1993

Accelerated tumor development in interferon-treated B6.C-Hyal-1 a mice.

The Hyal-1 locus, which we have previously described and mapped to mouse chromosome 9, influences the serum levels and molecular weight forms of hyaluronidase. We have also shown that the growth of two transplantable tumors, the 3LL carcinoma and the B16F10 melanoma, is influenced by the alleles at Hyal-1, in that the tumors develop more slowly in congenic B6.C-Hyal-1a (also called HW23) mice than in the parental Hyal-1b C57BL/6 mice. Here we present evidence that tumor development is stimulated and mortality is accelerated in B6.C-Hyal-1a mice grafted with 3LL carcinoma cells when treated with alpha/beta interferon (IFN-alpha/beta) or with IFN-beta, whereas in IFN-treated C57BL/6 mice 3LL tumor growth is inhibited. Likewise, in B6.C-Hyal-1a mice grafted with B16F10 melanoma cells, IFN-alpha/beta treatment results in stimulation of tumor growth, whereas in IFN-treated C57BL/6 mice tumor growth, whereas in IFN-treated C57BL/6 mice tumor growth is inhibited and mortality delayed. Thus, IFN-alpha/beta treatment of B6.C-Hyal-1a mice results in stimulation of tumor development and sometimes in accelerated mortality. This is the opposite of the usually described effect of IFN treatment in mice, which is inhibition of tumor development and delayed mortality, as was indeed observed in the C57BL/6 mice in the present experiments. These results provide the first indication that host genes can up- or down-regulate the antitumor activity of IFN and that, on some genetic backgrounds, IFN treatment enhances rather than inhibits tumor development. This may help to explain the apparent discordance between mouse model studies, which hitherto have consistently reported inhibition of tumor formation by IFN, and the clinical trials, in which only a limited percentage of individuals show tumor regression while others have no beneficial effect or even have progression of disease in spite of the IFN treatment.

Alleles↗
PubMed1993

Development of methods for somatic cell gene therapy directed against viral diseases, using retroviral vectors carrying the murine or human interferon-beta coding sequence: establishment of the antiviral state in human cells.

We are developing methods for somatic cell gene therapy directed against chronic and fatal virus infections, such as acquired immunodeficiency (AIDS), by transforming cells with a constitutively expressed interferon (IFN) coding sequence. Previous work from our laboratory has shown that stable antiviral expression (SAVE) can be obtained in murine BALB/c 3T3 cells and human U937 cells transformed with plasmids carrying either the murine or the human IFN-beta coding sequence placed under the expression control of a 0.6-kb Xho II-Nru I promoter region of the murine H-2Kb major histocompatibility complex (MHC) gene (Macé et al., 1991; Seif et al., 1991). In the present paper, we report the construction of murine (Mu) and human (Hu) IFN-beta-expressing retroviral vectors (pMPZen-MuIFN beta, pHMB-KbMuIFN beta) and the problems encountered. Because of the murine origin of commonly used packaging cells and the species specificity of IFN, it was evident that placing the murine IFN-beta sequence under constitutive expression control could result in the production of Mu IFN in the murine packaging system, and thereby lead to decreased vector production and also to enhanced resistance of target cells. Using a packaging cell line that releases a beta-galactosidase-expressing vector, we show that, as expected, Mu IFN-alpha/beta decreases vector production of murine packaging cells and also inhibits the transformation of target NIH-3T3 cells with this vector, but the presence of anti-Mu IFN antibodies rescues the viral titer of the packaging cells and restores the sensitivity of target cells to virus transformation. However, the same antibody treatment is unable to rescue the viral titer of psi-2 packaging cells producing autocrine Mu IFN-beta encoded by the pMPZen-MuIFN beta and pHMB-KbMuIFN beta vectors. Because of the species specificity of IFN, this problem is circumvented with the pMFG-HuIFN beta vector carrying the human IFN-beta sequence. In spite of the production of Hu IFN, murine psi-CRIP packaging cells are able to release retroviral vectors expressing Hu IFN-beta, and these amphotropic vectors can transform human MRC-5 cells and confer to these cells an enhanced resistance to vesicular stomatitis virus (VSV) infection.

3T3 Cells↗
PubMed1992

The growth rate of two transplantable murine tumors, 3LL lung carcinoma and B16F10 melanoma, is influenced by Hyal-1, a locus determining hyaluronidase levels and polymorphism.

The effect of 2 different levels of serum hyaluronidase on tumor development was studied by comparing the development of 2 transplantable tumors, the 3LL lung carcinoma and the B16F10 melanoma, in mice of the C57BL/6 and the congenic HW23 strains. The reasoning behind the study was that, in vitro, removal by hyaluronidase of the hyaluronan present in the extracellular matrix of tumor cells renders the latter more accessible to effector T cells. In the mouse, the levels and molecular forms of circulating hyaluronidase are under the influence of different alleles at the Hyal-1 locus on chromosome 9. C57BL/6 mice which have the Hyal-1b allele have only a 60,000-kDa form of hyaluronidase in the circulation, whereas the congenic HW23 strain has, on a C57BL/6 background, the BALB/c-derived Hyal-1a allele, characterized by the presence of the 60-, 120- and 140-kDa forms and of 3 times as much enzyme activity as the C57BL/6 strain. These 2 mouse strains that are genetically almost identical can therefore be used to compare the effect of different levels of circulating hyaluronidase on tumor development. Two different tumors were studied: the 3LL lung carcinoma and the B16F10 melanoma. After intrafootpad inoculation, both tumors developed more slowly in the congenic Hyal-1a HW23 strain, as measured by a slower rate of increase in local tumor size and by a prolonged survival time. These results are in favor of the hypothesis that the Hyal-1a allele, determining higher hyaluronidase levels, enhances resistance to tumor development.

Alleles↗
PubMed1992

Interferon-gamma.

During the past year, the most striking progress in our understanding of interferon-gamma has been made in the elucidation of the three-dimensional structure of the molecule and in the analysis of the molecular structure and the functional domains of the interferon-gamma receptor. A greater insight into the molecular mechanisms of gene activation by interferon-gamma has been gained, and the immunoregulatory role of interferon-gamma has been better defined in studies dealing with its effects on B-cell function and with its production by the various T-cell subsets. Finally, the effects of interferon-gamma on intracellular parasites is an important aspect of interferon-gamma activity that is giving rise to several clinical trials.

Animals↗
PubMed1991

Enhanced resistance to HIV-1 replication in U937 cells stably transfected with the human IFN-beta gene behind an MHC promoter fragment.

Cells of the monocyte lineage act as a major reservoir for HIV, and ways of enhancing the resistance of mononuclear phagocytes to HIV replication would be useful for delaying the onset of AIDS in infected individuals. Seif et al. (J. Virol. 65:664, 1991) have recently shown the possibility of obtaining stable antiviral expression (SAVE), directed against three nonretroviral RNA viruses, and normal cell viability in a significant percentage of murine BALB/c 3T3 cells transformed with an IFN-beta expression plasmid under the control of the 0.6-kb XhoII-NruI promoter region of the murine H-2Kb MHC gene. In the present paper, we show that it is possible to establish SAVE in human promonocytic cells. Cells of the human promonocytic U937 line were stably transfected with a human IFN-beta expression plasmid carrying the neo- and human IFN-beta-coding sequences under the control of the H-2Kb promoter fragment previously used in murine cells. After selection with G418, two transformed clones were isolated that released small amounts of human IFN-beta into the culture medium, without affecting the expression of CD4 and leucocyte function-associated Ag-1 differentiation Ag. The presence of construct-derived IFN-beta mRNA was demonstrated by polymerase chain reaction amplification of cDNA, and the level of 2-5A synthetase, one of the major IFN-induced antiviral proteins, was shown to be constitutively increased. These clones were less permissive for HIV-1 than control clones transformed with the neo gene only. The antiviral state could be modulated by anti-IFN-beta antibodies, in that the continuous presence of antibodies in the culture medium abolished the enhanced resistance to HIV-1 replication, whereas the withdrawal of the antiserum restored the antiviral state, indicating that it did indeed result from the constitutive synthesis of human IFN-beta. These results demonstrate the possibility of restricting HIV-1 replication in human promonocytic cells by establishing SAVE. Further exploration of this method as a possible approach to somatic cell gene therapy of HIV infection appears worthwhile.

2',5'-Oligoadenylate Synthetase↗
PubMed1991

Linkage analysis of the murine Hyal-1 locus on chromosome 9.

We have recently described a new locus, Hyal-1, which determines hyaluronidase variants in mouse serum. On the basis of segregation in recombinant inbred and congenic strains, Hyal-1 was tentatively assigned to chromosome 9 (Fiszer-Szafarz and De Maeyer, '89). In the present study we have performed a linkage analysis of Hyal-1 using 156 backcross progeny of an interspecies cross of laboratory mice and Mus Spretus. Linkage was tested to two anchor loci on chromosome 9: d (dilute, a coat color locus) and Bgl-s (a locus controlling beta-galactosidase activity). The gene order (from centromere) with intervening percentage recombination is d-16.6 (+/- 2.9)-Hyal-1-10.9 (+/- 2.4)-Bgl-s, indicating close linkage to H-7 and Fv-2.

Animals↗
PubMed1991

Stable antiviral expression in BALB/c 3T3 cells carrying a beta interferon sequence behind a major histocompatibility complex promoter fragment.

We are exploring the use of interferon (IFN) genes for somatic cell gene therapy and have investigated the possibility of transforming cells into low constitutive IFN producers over prolonged periods of time without impeding cell survival or replication. Here we report the possibility of conferring a permanent antiviral state to cells by introducing an IFN-beta gene with a modified transcriptional control. This was achieved by placing the murine IFN-beta-coding sequence behind the IFN-inducible 0.6-kb XhoII-NruI promoter region of the H-2Kb major histocompatibility complex gene. BALB/c 3T3 cells that are normally permissive for virus infection were transformed with this construction, and 14 of the 21 clonal cell lines obtained displayed different levels of enhanced resistance to the replication of vesicular stomatitis virus, encephalomyocarditis virus, and Semliki Forest virus. The permanent antiviral state was dependent on the presence of new IFN-beta fragments in Southern blots and was accompanied by very low constitutive synthesis of IFN-beta, and the presence of construct-derived IFN mRNA could be demonstrated only after polymerase chain reaction amplification of cDNA. The antiviral state was stable over a 9-month period in culture, corresponding to about 250 cell generations, and did not affect cell replication, since the average population doubling time of these cells was not significantly different from that of the control clone. Twenty-nine control clonal cell lines, stably transformed with either the neo gene alone (22 lines) or the neo gene together with a mutated murine IFN-beta gene coding for an inactive protein (7 lines), did not develop stable antiviral expression. We conclude that low constitutive synthesis of autocrine IFN-beta is sufficient to induce a permanent antiviral state, is compatible with cell survival and replication, and therefore merits further exploration for use in somatic cell gene therapy.

Animals↗
PubMed1989

Linkage analysis of the murine mos proto-oncogene on chromosome 4.

A linkage analysis of the murine Mos gene, which codes for the c-mos proto-oncogene, was performed in 88 backcross progeny of an interspecies cross of laboratory mice and Mus spretus. Linkage was tested for four different genes on mouse chromosome 4: Aco-1, Mup-1, b, and Ifb. The gene order (from centromere) with intervening percentage recombination is Mos-15.9 (+/- 3.9)-Aco-1-5.6 (+/- 2.4)-Mup-1-3.4 (+/- 1.9)-b-5.6 (+/- 2.4)-Ifb. These results confirm the previous assignment of Mos to chromosome 4 on the basis of segregation in somatic cell hybrids (D. Swan et al., 1982, J. Virol. 44: 752-754) and show furthermore that Mos and the Ifa/Ifb clusters are not tightly linked as a group of intronless genes, but are separated by a map distance of 30.6 +/- 4.9 recombination units. The linkage data obtained in the present study place Mos in a region compatible with the physical map (D. W. Threadgill and J. E. Womack, 1988, Genomics 3: 82-86).

Aconitate Hydratase↗
PubMed1986

Natural antibodies to interferon-alpha and interferon-beta are a common feature of inbred mouse strains.

Neutralizing antibodies to murine interferon-alpha (MuIFN-alpha) and MuIFN-beta of the immunoglobulin (Ig)G and IgM class were naturally present in sera of BALB/c and C57BL/6 mice of four different age groups, ranging from 1 to 15 mo. These antibodies not only neutralized IFN made by C-243 cells (Swiss genotype), but also isogenic IFN-alpha and IFN-beta, and can therefore be considered to be real autoantibodies. Natural anti-MuIFN antibodies were also found in the sera of mice from 12 other inbred strains, and seem to be a common feature of inbred mouse strains.

Animals↗
PubMed1986

Structure and expression of a new murine interferon-alpha gene: MuIFN-alpha I9.

A new murine alpha interferon gene, MuIFN-alpha I9, isolated from a BALB/c genomic clone, was characterized. It encodes a mature polypeptide of 167 amino acids (aa), presenting from 77 to 86% homology with the seven other MuIFN-alpha I aa sequences previously described. When compared to the latter, pre-IFN-alpha I9 has 13 distinctive aa, and, remarkably, ten of these occur in pairs. The coding region, fused to the SV40 early promoter and introduced into COS monkey cells, directed the transient secretion of an acid-stable functional IFN of 18-21 kDa. The production in this system reached levels of 300 000 units per 0.15 ml. A comparison of the aa sequence of different murine, rat, bovine, and human alpha and beta IFNs revealed certain common features allowing us to propose a putative secondary structure of the IFN proteins. A detailed analysis of results previously published by us and by others showed that the MuIFN-alpha I9 gene is, together with a least twelve other MuIFN-alpha I genes, located on chromosome 4.

Amino Acid Sequence↗
PubMed1986

Interferon structural genes do not participate in quantitative regulation of interferon production by If loci as shown in C57BL/6 mice that are congenic with BALB/c mice at the alpha interferon gene cluster.

Previous studies have shown that serum interferon (IFN) production in mice is quantitatively influenced by If loci, whose alleles determine high or low production. Although different loci influence IFN production in response to different inducers, such as Newcastle disease virus, Sendai virus, herpes simplex virus type 1, and polyriboinosinic-polyribocytidylic acid, BALB/c mice are in every instance low producers. It was therefore possible that, in addition to If loci, some feature of the BALB/c structural IFN genes contributed to low production. This was examined in the present work, in which IFN production was measured in two strains of C57BL/6 mice congenic with BALB/c at the murine alpha IFN (IFN-alpha) gene cluster on chromosome 4. One line, HW13 (B6.C-H-15c-H-16c-H-20c-H-21c/By) has a BALB/c fragment on chromosome 4 of at least 35 centimorgans which includes the BALB/c IFN-alpha gene cluster and four loci of the brown histocompatibility complex; the other line, HW13J (B6.C-H-15c/By), has a much shorter fragment (about 15 centimorgans), but it also comprises the BALB/c IFN-alpha gene cluster. We show that these mice, carrying the BALB/c IFN-alpha structural genes on a C57BL/6 background, are high IFN producers when stimulated by Newcastle disease virus, Sendai virus, herpes simplex virus type 1, or polyriboinosinic-polyribocytidylic acid. Thus, the low IFN production of BALB/c mice is not directly due to some feature of the IFN-alpha structural genes but is mainly the result of different alleles at If loci.

Alleles↗
PubMed1985

Identification of individual interferon-producing cells by in situ hybridization.

Individual interferon (IFN)-producing cells were identified by hybridization in situ followed by autoradiography. cDNAs corresponding to murine IFN-alpha and murine IFN-beta labeled by nick-translation to high specific activity (2-4 X 10(8) dpm/micrograms) with alpha-35S-labeled dATP were used as probes for hybridization with IFN mRNA in mouse C-243 cells induced with Newcastle disease virus. Control experiments with non-induced cells or with non-IFN-related labeled DNA monitored the specificity of the autoradiographic signal. Under optimal conditions of IFN induction, between 15% and 40% of the cells gave a hybridization signal with a mixture of IFN-alpha and -beta probes. Differential hybridization with either the IFN-alpha or -beta probe or a mixture of both, at three different time intervals after induction, revealed that only a small fraction of cells had detectable amounts of IFN-alpha mRNA, whereas in the majority of the positive cells IFN-beta mRNA was present.

Animals↗
PubMed1985

The antiproliferative effect of murine interferon alpha/beta on early bone marrow-derived erythroid precursors (BFU/e).

We have examined the antiproliferative effect of murine interferon (MuIFN) alpha/beta on a primitive class of erythroid precursors, the burst-forming units (BFUe) which give rise to macroscopic colonies of erythroblasts in plasma clots. Cultures were examined respectively on day 9 and on day 15; in both instances there was a significant reduction in the number of erythropoietic bursts in cultures exposed to IFN. The effect of IFN was more pronounced when the cells were cultured in the presence of suboptimal concentrations of erythropoietin and it could to a significant extent be reversed by ouabain at 10(-15) M. The latter finding is in line with observations made by others that growth factors can act as IFN antagonists. A comparison of BFUe derived from mice of two different genotypes, BALB/c and C57BL/6, revealed no difference in relative sensitivity to the antiproliferative effect of IFN. This is in contrast with the previously described fivefold greater sensitivity of the BALB/c genotype when a more differentiated class of erythroid precursors, the colony-forming units or CFUe, are exposed to IFN. Since the BFUe, studied in the present work, are a more primitive class of erythroid precursors than the CFUe, it can be concluded that the genes modulating the difference in sensitivity to IFN action on erythroid precursors are only expressed after a certain stage of differentiation has been reached.

Animals↗