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Biomedical subjects

M Revel

Publications and source records attributed to M Revel.

At least 199 records · Page 11Linked to original sources
PubMed1983

The beta2-microglobulin mRNA in human Daudi cells has a mutated initiation codon but is still inducible by interferon.

The human Burkitt lymphoma cell line Daudi does not synthesize beta2-microglobulin (beta2m) and lacks the cell surface histocompatibility antigens. The cells, however, contain RNA hybridizing to a cloned human beta2m cDNA probe. cDNA from this Daudi beta2m RNA, was cloned and sequenced. By comparison with cDNA prepared from Ramos cells, which synthesized microglobulin, we determined the sequence of the 20 amino acid long leader peptide of pre-beta2m and show that in Daudi cells the initiator ATG has been mutated to ATC. Although Daudi beta2m RNA cannot be translated, interferon induces the beta2m RNA in Daudi cells as well as in normal human cells.

Amino Acid Sequence↗
PubMed1983

Sequences involved in the regulated expression of the human interferon-beta1 gene in recombinant SV40 DNA vectors replicating in monkey cells.

The human genomic EcoRI fragment of 1.83 kb containing the interferon (IFN) gene IFN-beta1 with 285 nucleotides of 5'-flanking sequences was transfected into monkey kidney CV-1 cells as part of an SV40-pML2 vector. Induction of the monkey cells to produce IFN led to a rapid accumulation of IFN-beta1 RNA whose 5' ends were identical to the IFN-beta1 mRNA of human fibroblasts. This induction occurred with all recombinants tested. Expression from the SV40 late promoter was also seen in non-induced cells. We conclude that the regulation of the IFN-beta1 gene is retained in the replicating episomal SV40 vectors with high copy number, even when the gene is being transcribed from an external promoter. When the 5'-flanking sequences were deleted to leave only 40 bp before the presumed cap site of the IFN-beta1 gene, inducible formation of IFN-RNA with authentic 5' ends could still be demonstrated. However, inducibility and expression depended on the position of the deleted IFN-beta1 gene in the vector. We conclude that the sequences around the TATAA box and cap site on the IFN gene are involved in the regulation of its expression. Regulated short-term expression of the human IFN-beta1 gene in SV40 vectors provides a defined system in which the structures required to maintain the regulation and the influence of known external transcription signals can be examined.

5' Flanking Region↗
PubMed1983

Differential regulation of HLA-DR mRNAs and cell surface antigens by interferon.

Human interferons-alpha, -beta and -gamma enhance HLA-DR mRNAs in all the human lymphoblastoid and melanoma cell lines studied. The increase concerns both alpha and beta chain mRNAs. Moreover, we show that immune interferon-gamma preferentially enhances class II MHC mRNA. This effect of IFN-gamma on the synthesis of alpha and beta HLA-DR chains has been also analysed by immunoprecipitation. It is abolished by a monoclonal antibody directed against human IFN-gamma. The effect of interferon on the cell surface level of HLA-DR molecules does not always correspond to the enhancement of HLA-DR mRNA. Our experiments suggest that this discrepancy between the enhancement of HLA-DR mRNA and cell surface antigen might be due to a constitutively high level of the corresponding antigens on several of the human cells studied.

B-Lymphocytes↗
PubMed1983

Presence of an abnormal beta 2-microglobulin mRNA in Daudi cells: induction by interferon.

Human alpha and beta interferons increase the amount of class I human histocompatibility messenger RNA HLA-A, B, C and beta 2-microglobulin in most human cells studied to date. This report concerns the effect of interferons on the Burkitt lymphoma-derived cell line Daudi, which does not express HLA-A, B, C antigens or beta 2-microglobulin on its membrane. HLA-A, B, C messenger RNA present in Daudi cells is increased by both alpha and beta interferons. Furthermore, we have shown that although it was not possible to detect mature beta 2-microglobulin protein in the cytoplasm or on the cell membrane of Daudi cells, a poly A+ messenger RNA is present in Daudi cells, which hybridizes with a cDNA clone specific for human beta 2-microglobulin. This abnormal messenger RNA is, however, increased normally by interferon. These effects were also observed with human interferon beta on a variant of Daudi cells characterized by a markedly reduced sensitivity to anti-proliferative and anti-cellular effects of human interferon alpha.

Beta-Globulins↗
PubMed1983

Molecular cloning and sequence of partial cDNA for interferon-induced (2'-5')oligo(A) synthetase mRNA from human cells.

By using a translation assay in oocytes, a 17S RNA fraction coding for the interferon-induced (2'-5')oligo(A) synthetase was purified from human cells. A cDNA library was prepared by cloning in Escherichia coli plasmid pBR322 and screened by positive hybridization-translation in oocytes. A cDNA clone corresponding to the (2'-5')oligo(A) synthetase mRNA was identified. In SV80 cells, this E cDNA recognizes three RNAs of 1.65, 1.85, and 3.6 kilobases, which are present only after interferon treatment of the cells. In Namalva cells, mainly one RNA of 1.8 kilobases is seen.

2',5'-Oligoadenylate Synthetase↗
PubMed1983

Affinity chromatography of human fibroblast interferon (IFN-beta 1) by monoclonal antibody columns.

Eight hybridomas secreting monoclonal antibodies specific to human fibroblast interferon (IFN-beta 1) were identified by a new screening procedure based on immune precipitation with a second antibody and recovery of interferon activity from the immune precipitate. Immunoadsorbents were prepared from these monoclonal antibodies and used for purification of IFN-beta 1. Electrophoretically pure IFN-beta 1, having a specific activity of 3 X 10(8) to 6 X 10(8) units/mg was obtained by a single passage of partially purified IFN-beta 1 on these immunoadsorbents.

Animals↗
PubMed1983

Cycloheximide induces expression of the human interferon beta 1 gene in mouse cells transformed by bovine papillomavirus-interferon beta 1 recombinants.

Mouse cells transformed by a bovine papillomavirus recombinant vector containing the human interferon (IFN) beta 1 (IFN-beta 1) gene could be induced to produce human as well as mouse IFNs. The optimal conditions for induction of human IFN and of its mRNA in these transformants resembled those needed for mouse IFN: high concentrations of DEAE-dextran and low concentrations of polyriboinosinic acid-polyribocytidylic acid. Superinduction by inhibitors of protein synthesis which strongly stimulate IFN-beta 1 induction in human cells had only a small effect on human IFN induction in bovine papillomavirus IFN-beta 1-transformed mouse cells. In contrast, cycloheximide without double-stranded RNA could induce significant levels of human IFN in the bovine papillomavirus IFN-beta 1 mouse transformants. After cycloheximide treatment, these cells contained IFN-beta 1 mRNA whose 5' ends originated in the authentic start site of the human IFN-beta 1 gene, as shown by S1 nuclease mapping. The transferred human gene, propagated extrachromosomally in the mouse cells, was, therefore, inducible under conditions different from those in human cells. The results also confirmed that the inhibitor of protein synthesis, cycloheximide, can induce expression of a human IFN gene.

Animals↗
PubMed1983

Inducible expression of the human interferon beta 1 gene linked to a bovine papilloma virus DNA vector and maintained extrachromosomally in mouse cells.

A 1.6-kilobase DNA segment of the genomic human interferon beta 1 (IF-beta 1) gene was inserted into each of two possible orientations at the single HindIII site of a recombinant plasmid pBPV69T, consisting of the 69% transforming region of the bovine papilloma virus type 1 (BPV-1) and a modified SalI-SalI fragment of plasmid pBR322. After cleavage of the pBR322 sequences from this recombinant, BPV69T-IF-beta 1 hybrid DNAs were transfected onto C127 mouse cells by the standard calcium precipitation technique. Mouse cells transformed by this hybrid DNA produced low levels of human IF-beta 1 constitutively and responded to induction with either inactivated Newcastle disease virus or polyriboinosinic acid-polyribocytidylic acid. The BPV69T-IF-beta 1 hybrid DNA was nonintegrated in the transformed mouse cells but had acquired DNA sequences as a result of the transfection. Accurate transcripts of the IF-beta 1 mRNA were detected in cells only after induction. When the IF-beta 1 gene was oriented in the plasmid in the same direction of transcription as the BPV-1 genome, transcription was promoted from within the BPV-1 sequences. These results indicate that the regulatory sequences responsible for the inducible expression of the human IF-beta 1 gene are present in the 1.6-kilobase genomic segment and that these sequences can function in a free extrachromosomal state linked to BPV-1 sequences.

Animals↗
PubMed1983

Clinical effect of human-fibroblast-derived (beta) interferon in treatment of adeno-virus epidemic keratoconjunctivitis and its complication.

The clinical studies reviewed here indicated the usefulness of topical application of Human-fibroblast-derived (Beta) interferon (HulFN-B) in treatment of Adeno-8 Epidemic-keratoconjunctivitis. A week treatment with 2-5 X 10(5) reference units daily doses, starting early as possible, reduced the length of the disease from 22 day to a week, and almost totally prevented the appearance of subepithelial keratitis which occurred in 57% of the control group. Possibly interferon should be given also prophylactically to individuals exposed to contagion. Our results encourage further investigation on the Hul FN-B use as a drug for treatment and prevention of viral infection.

Administration, Topical↗
PubMed1982

Preferential effect of gamma interferon on the synthesis of HLA antigens and their mRNAs in human cells.

Interferons produce a variety of biological effects on cells. They induce resistance to virus proliferation, inhibit cell growth, modify cell structure and differentiation, stimulate some immune functions and inhibit others. However, the different interferon (IFN) species may vary in their mechanism of action and, hence, in their relative efficiency for inducing each of the effect. IFN-gamma (type II) appears to show stronger immunoregulatory and growth inhibitory effects than antiviral effects, but this conclusion has been challenged in other reports. The aim of the present work is to compare the action of IFN-gamma and other (type I) interferons on the induction of (2'-5') oligo(A) synthetase which is probably part of the antiviral response and the induction of the histocompatibility HLA-A,-B,-C antigens. We have shown previously that the induction of both proteins is regulated by interferons at the mRNA level, but show here that IFN-gamma from stimulated human lymphocytes and from monkey cells transfected by cloned human IFN-gamma cDNA induced the HLA-A,-B,-C and beta 2-microglobulin mRNAs or proteins at concentrations over 100 times lower than those needed to induce the (2'-5')oligo(A) synthetase and the antiviral state. This difference was not found with IFN-alpha and -beta (type I).

2',5'-Oligoadenylate Synthetase↗
PubMed1982

Interferon-dependent induction of mRNA for the major histocompatibility antigens in human fibroblasts and lymphoblastoid cells.

In human cells treated with interferons, there is an increase in the amount of HLA-A,B,C and beta 2-microglobulin exposed on the cell surface. We have used a cloned HLA-A,B,C cDNA probe to demonstrate by molecular hybridization that this effect of interferon is preceded by a large increase in the amount of HLA mRNA in the cell. This effect was found in five different human cell lines, with purified leukocyte and fibroblast interferons. The increase in HLA mRNA is comparable in its kinetics and dose-response to the induction of (2'-5') oligo(A) synthetase mRNA by interferons. Therefore, interferons seem to activate at least two cellular genes which have different biochemical functions.

Cells, Cultured↗
PubMed1982

Comparison of (2'-5') oligo-adenylate synthetase and interferon blood-levels in mice early after viral infection.

The level of the IFN-induced enzyme (2'-5') oligo A synthetase in the peripheral blood mononuclear cells (PBMC) was determined in mice at different times following virus infection. There was a significant increase (4-7-fold) of the enzyme level within less than 12 h after i.p. injection of either VSV (10(7) pfu) or Sindbis virus (2.10(4) pfu). The elevated level was maintained for about a week and then the activity returned to normal. There was, however, a marked difference in the pattern of serum level of IFN during infection by the two viruses; while in the mice infected by VSV, serum IFN was very high on the first day and declined to an undetectable level by the fourth day, in the mice infected with Sindbis virus, serum IFN was barely detectable at the first day and then increased towards the fourth day of infection. Antiviral antibodies could be detected in the serum only about a week after infection. We conclude that viral infection can result in a rapid elevation of (2'-5') oligo A synthetase in the PBMC, even when serum IFN remains low. Thus, quantitation of the enzyme level can be a useful diagnostic aid in viral infection particularly in the early stages and in cases in which antiviral antibodies and IFN can not be detected.

2',5'-Oligoadenylate Synthetase↗
PubMed1982

Variation of (2'-5') oligo A synthetase level in lymphocytes and granulocytes of patients with viral infections and leukemia.

Using a simplified technique for the determination of oligoisoadenylate synthetase activity, we have compared the cellular level of this interferon (IFN)-induced enzyme in multiple samples of peripheral blood leukocytes. In mononuclear cells (PBMC) of healthy donors the enzyme level was remarkably constant, but in the cells of about 85% of patients with viral infections enzyme activity was significantly elevated. In contrast, the incidence of elevated activity in bacterial infections was low. Synthetase activity could be also detected in granulocytes, although normally its level in these cells was considerably lower than in PBMC. A sharp increase in the enzyme level in granulocytes was found in cells exposed in vitro to IFN, as well as in cells from patients undergoing IFN therapy. Increased synthetase activity was also detected in the granulocytes of patients with viral infections. We have also determined the level of the enzyme in patients with various types of leukemias. In a large proportion of the patients with acute lymphoblastic leukemia (ALL) we found severely decreased enzyme levels (10-20% of control value). The decreased activity could usually be correlated to predominance of blast cells in the peripheral blood.

2',5'-Oligoadenylate Synthetase↗