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Biomedical subjects

A Meager

Publications and source records attributed to A Meager.

At least 145 records · Page 8Linked to original sources
PubMed1982

Spontaneous production of gamma interferon and induced production of beta interferon by human T-lymphoblastoid cell lines.

Two human T-lymphoblastoid cell lines, CCRF/CEM and Molt 4, produced beta interferon (IFN-beta) upon infection with Sendai virus. Molt 4, but not CCRF/CEM, spontaneously produced up to 300 U of IFN-gamma per ml, apparently not contaminated with IFN-alpha or -beta. Phytohemagglutinin, a T-cell mitogen, did not stimulate IFN production in these lines. A third T-lymphoblastoid line, CCRF/HSB2, produced no IFN either spontaneously or after infection with Sendai virus or treatment with phytohemagglutinin. The Molt 4 cells contained an mRNA which could be translated by oocytes to give IFN-gamma. Molt 4 cells therefore provide a convenient source of human IFN-gamma and its mRNA for experimental purposes.

Bromodeoxyuridine↗
PubMed1981

Immune interferon produced to high levels by antigenic stimulation of human lymphocytes with influenza virus.

Influenza virus stimulation of human lymphocytes induced high levels of immune interferon in lymphocyte cultures. The lymphocytes of normal adults produced approximately 1,000 U/10(6) cells, which was in large part gamma interferon. The lymphocytes of individuals recently vaccinated yielded very high levels (10-50,000 U/10(6) cells) of interferon. The interferon was pH 2 labile, and was not neutralized by antisera to alpha or beta interferon. It did not bind to a monoclonal antibody to alpha interferon, and after partial purification it had characteristics identical to human gamma interferon induced by phytohemagglutinin. The highest yields were produced by treatment of stimulator cells with live virus. Stimulation by whole inactivated virus resulted in lower levels of interferon, and purified hemagglutinin did not induce interferon. The antigen responsible for stimulating the lymphocyte response and interferon induction is a cross-reactive determinant present on all human and non-human influenza viruses tested.

Antigens, Viral↗
PubMed1981

Production and screening of cell hybrids producing a monoclonal antibody to human interferon-alpha.

Mice and rats were immunized with human lymphoblastoid interferon, a mixture of human leukocyte (interferon-alpha) and human fibroblast (interferon-beta) interferons, and their serum anti-interferon levels measured. Anti-interferon activity was detected in all animals, although the mouse sera had higher titers than the rat sera. The spleens of two mice were removed and used to prepare hybrid myelomas. Anti-interferon activity in tissue culture supernatants was measured using a direct neutralization assay and a clone (NK2) producing antibody to human interferon-alpha (leukocyte) was isolated. The anti-interferon activity of this monoclonal antibody was confirmed using a new indirect immunoprecipitation (IIP) assay, which shows some advantages over the direct neutralization assay. The antibody did not neutralize human interferon-beta (fibroblast) or mouse interferon.

Animals↗
PubMed1980

Interferon production by human-mouse hybrid cells: dominant mouse control of superinduction and priming.

We have examined the production of interferon by a number of human-mouse hybrid clones in response to polyriboinosinic acid:polyribocytidylic acid copolymer [poly(rI).poly(rC)] all of which produced both human and mouse interferons when stimulated with a virus. Their capacity to be superinduced and primed for interferon production in response to poly(rI).poly(rC) was compared to that of the parental human and mouse cells. It was found that the hybrids responded in a way similar to their mouse cell parents, indicating dominant mouse control of both the priming and superinduction phenomena.

Animals↗
PubMed1979

Characterization of interferon messenger RNA from human lymphoblastoid cells.

After treatment with Sendai virus, Namalwa cells form large amounts of interferon. RNA extracted from treated whole cells or from their polysomes was injected into Xenopus laevis oocytes and the interferon formed was titrated. The results show that the amount of interferon mRNA was maximal by 9 h after treatment of the cells with Sendai virus and then declined. Sucrose gradient centrifugation of the mRNA gave substantial purification and showed that its size was 12 S.

Animals↗
PubMed1979

Somatic cell genetics of human interferon production in human-rodent cell hybrids.

Forty-two primary human-mouse cell hybrids, derived in two separate experiments, were treated with Newcastle disease virus (NDV): eight hybrids were found to produce human interferon and this was shown in every case to be predominantly of the fibroblast type. An extensive analysis was made in terms of karyotype and marker enzymes on all the eight hybrids producing interferon and also on five hybrids which did not produce interferon, five randomly selected hybrids and eleven subclones resistant to diphtheria toxin. The results suggest that, contrary to previous reports, a gene on chromosome 5 is not involved in production of human interferon. Its production was however correlated with the presence of chromosome 9 in the hybrids. Analyses of two sets of human-Chinese hamster hybrid subclones from two different crosses were also consistent with the assignment of a human interferon gene to chromosome 9.

Animals↗
PubMed1979

Interferon production: variation in yields from human cell lines.

A survey of human diploid, aneusomic, transformed and tumor fibroblast or fibroblastoid cell lines for their capacity to produce interferon after polyriboinosinic acid:polycytidylic acid induction showed considerable variation in responsiveness. There was no apparent correlation between karyotype or phenotype and interferon production. Pretreating or "priming" the cells with human interferon generally led to increased yields of interferon after polyriboinosinic acid:polycytidylic acid induction in all cell lines tested. All the cells also showed the "super-induction" phenomenon, although to varying degrees. The combination of priming and superinduction conditions led to the production of very high yields of interferon in some cell lines, but in other lines, yields less than either the primed or superinduced amounts were found. A more limited survey of human cell lines for their capacity to produce interferon after Newcastle disease virus induction also showed that yields varied from line to line. However, there was little evidence to suggest that ability to produce interferon after Newcastle disease virus induction correlated with that after polyriboinosinic acid:polycytidylic acid induction.

Cell Line↗
PubMed1977

Effect of 2-deoxy-D-glucose on the cell-surface glycoproteins of hamster fibroblasts,.

1. Growth of baby hamster kidney (BHK) cells in medium containing 2-deoxy-D-glucose is retarded in direct proportion of the 2-deoxyglucose concentration. The severity of the effect is reduced in medium containing high relative concentrations of glucose. 2. 2-Deoxyglucose inhibits the incorporation of radioactivity from mannose, galactose, glucosamine, fucose and N-acetylmannosamine precursors into acid-insoluble cellular material. Incorporation of radioactively labelled leucine into protein is not affected by 2-deoxyglucose. 3. BHK cells grown in the presence of 2-deoxyglucose become less sensitive to the toxic action of certain plant lectins, ricin of Ricinus communis and Phaseolus vulgaris phytohaemagglutinin, which bind specifically to cell surface galactose and N-acetyl-galactosamine residues. By contrast, 2-deoxyglucose increased the sensitivity of BHK cells to the weak toxicity of concanavalin A, which binds to surface mannosides. Treated cells also become more agglutinable with concanavalin A. 4. Cell surface glycoprotein labelled by lactoperoxidase-catalysed iodination have been examined by dodecylsulphate-polyacrylamide gel electrophoresis. The radio-iodinated glycoprotein prepared from cells grown in medium containing 2-deoxyglucose migrate more rapidly than glycoproteins from cells grown in the absence of inhibitor.

Cell Division↗
PubMed1977

Properties of a baby-hamster-kidney cell line with increased resistance of 2-deoxy-D-glucose.

A cultured cell line with increased resistance to 2-deoxy-D-glucose was obtained from cloned baby hamster kidney fibroblasts, BHK 21/C13, after repeated exposure to high concentrations of 2-deoxyglucose. The increased resistance could not be attributed to a decreased permeability of deoxysugar. The resistant cell line incorporated radioactive 2-deoxy-Dglucose in glycoproteins at a similar rate as parental BHK 21C13 cells. Incorporation of radioactive glucosamine, galactose and to lesser extent mannose into cellular glycoproteins was inhibited by 2-deoxyglucose to similar extents in the resistant cells and parental BHK 21/C13 cells. Changes induct cells were detected by altered to toxic plant lectins and by surface labelling as described for parental cells in the preceding paper. It is suggested that the toxicity of 2-deoxy-D-glucose to normal fibroblasts is not mediated through effects on glycosylation of cellular glycoproteins.

Cell Division↗
PubMed1976

Variants of hamster fibroblasts resistant to Ricinus communis toxin (ricin).

1. Variant baby-hamster kidney (BHK) cell lines were isolated that grow in the presence of high concentrations of ricin, the toxic lectin of castor beans (Ricinus communis). The variant lines were independently derived from several cultures of normal BHK cells which had been exposed to the mutagen, methyl-N-nitro-N-nitrosoguanidine, before selection by ricin. 2. The cell lines maintain a high degree of resistance to ricin after growth in lectin-free medium for prolonged periods and therefore exhibit stable phenotypes that are different from normal BHK cells. 3. A preliminary classification of the phenotypes was made. Several cell lines bind normal amounts of 125I-labelled ricin, whereas other bind the lectin poorly. 4. A loss of surface receptors for two other lectins, R. communis RCA and Axinella polyploides, which have specificities similar to ricin, was also found in some but not all of the cell lines showing decreased surface concentrations of ricin receptors. 5. The binding to the ricin-resistant cells of lectins of different sugar specificity, namely Lens culinaris lectin and concanavalin A, was similar to, or higher than, to normal BHK cells. 6. Several of the ricin-resistant cell lines were shown to be cross-resistant to the weak cytotoxicity of Phaseolus vulgaris lectin. By contrast, some cell lines were more sensitive to concanavalin A than were normal BHK cells.

Agglutination↗
PubMed1976

Interactions of KB-cell glycoproteins with an adenovirus capsid protein.

Glycoprotein material extracted from human KB cells with a flurocarbon, trichlorotrifluoroethane (Arklone P), into a waste-soluble fraction binds to fibre, a structural protein of the adenovirus type-5 capsid. The fibre-binding glycoprotein(s) were purified by ion-exchange chromatography on DEAE-Sephadex and affinity chromatography on a fibre-Sepharose support. The purification procedure also includes a trypsinization step which eliminates the bulk of contaminating KB cell proteins present in the aqueous fraction without appreciably affecting the activity of the fibre-binding glycoprotein(s). Some comparison is made of the membrane-bound receptors for adenovirus and the water-soluble fibre-binding glycoprotein(s).

Adenoviridae↗