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Biomedical subjects

S E Grossberg

Publications and source records attributed to S E Grossberg.

At least 55 records · Page 3Linked to original sources
PubMed1985

HuIFN-gamma antiviral activity correlates with immunological reactivity in a double-monoclonal antibody radiometric assay.

Several lines of evidence have been obtained that correlate biological activity with reactivity in an immunoradiometric assay (IRMA) employing two different monoclonal antibodies. Antiviral activity and immunological reactivity decreased in parallel when freeze-dried human gamma-interferon (HuIFN-gamma) was heated for prolonged periods of time at elevated temperatures. Likewise, aqueous preparations of HuIFN-gamma inactivated by acid pH or heat responded similarly in the biological assay and IRMA. These results indicate that the monoclonal antibodies used in this commercially available IRMA are specific for the epitopes on biologically activity HuIFN-gamma.

Antibodies, Monoclonal↗
PubMed1985

Suppression of the mixed leukocyte reaction by serum from polynucleotide-injected mice.

Sera from mice which have been injected iv with either poly(A) X poly(U) or poly(I) X poly(C) 1 1/2 hr prior to bleeding were found to suppress the mixed lymphocyte reaction. This effect was reduced considerably by 18 hr. Characterization of the suppressive sera revealed it (a) was stable to heating at 56 degrees C for 1 hr and freezing at -20 degrees C for 1 month; (b) had a molecular weight greater than 30,000; (c) could be induced in sera from athymic nude mice; and (d) was present to a lower degree in sera from aging mice.

Adjuvants, Immunologic↗
PubMed1985

Leukocyte tubuloreticular inclusions in Reye's syndrome.

Tubuloreticular inclusions (TRI) have been observed in the rough endoplasmic reticulum of blood lymphocytes and monocytes in two cases of Reye's syndrome initiated by influenza infections. Tubuloreticular inclusions are seen in these mononuclear leukocytes during the acute phase of illness, but not during convalescence. Since TRI have been demonstrated in peripheral mononuclear leukocytes in patients with acquired immunodeficiency syndrome, systemic lupus erythematosus, and certain viral infections including T-cell leukemia, it may be that the finding of TRI in Reye's syndrome reflects a viral infection and/or immune dysfunction, if such association is not proved to be fortuitous.

Acute Disease↗
PubMed1985

Cytotoxicity of human beta-interferon for differentiating leukemic HL-60 cells.

We examined the effect of human interferon (HuIFN) -alpha and -beta on the proliferation and differentiation induced by dimethyl sulfoxide (DMSO) of HL-60 human promyelocytic leukemia cells into mature granulocytes. Neither HuIFN-alpha nor -beta, alone, from 1 to 1000 IU/ml, nor the homologous mock HuIFN preparations affected HL-60 cell differentiation or proliferation. Whereas the combination of HuIFN-alpha (10 to 1000 IU/ml) with DMSO also did not affect the proliferation or differentiation of HL-60 cells, the addition of HuIFN-beta (1000 IU/ml) and DMSO (1.25%) to growing cultures reduced cell viability as much as 14% of that observed for cells treated with DMSO alone or to 4% of that observed for either untreated cells or those treated with HuIFN-beta alone. The cytotoxic effect declined with decreasing concentrations of HuIFN-beta. The cytotoxic effect of DMSO and HuIFN-beta was exerted only as cells began to differentiate. Removal of HuIFN-beta at Day 2 did not reverse the cytotoxic effect, and addition of HuIFN-beta at Day 2 did not inhibit cell proliferation. Addition of HuIFN-beta to postmitotic cells on Day 4 after DMSO treatment did not affect proliferation but did slow differentiation. The cytotoxic and antidifferentiative effects of naturally produced HuIFN-beta were confirmed with highly purified recombinant HuIFN-beta. Undifferentiated HL-60 cells were resistant to the antiviral effects of HuIFN-beta, requiring 4 to 6 times the concentration to protect 50% of the cells against vesicular stomatitis virus as that needed to produce a cytotoxic or antidifferentiative effect. The profoundly cytotoxic effects of HuIFN-beta reported here may provide a model to study this interferon in combination with inducers of leukemic cell differentiation as a possible strategy in cancer therapy.

Antibodies↗
PubMed1984

Markedly enhanced production of gamma interferon in murine T lymphocytes treated with lentil lectin and the diterpene ester, mezerein.

Gamma interferon (IFN-gamma) was induced in murine splenocytes first stimulated to grow by concanavalin A (Con A) and subsequently treated for 3 h with the diterpene ester, mezerein (MZN) and then with lectin from Lens culinaris for 24 h. Yields as high as 60,000 u/ml were obtained in cells from either male or female, random-bred, white Swiss mice or inbred C67B1/6 mice. Antibody to Thy 1.2 surface antigen completely obliterated the mouse gamma interferon (MuIFN-gamma) response, whereas anti-Lyt 1.2 and anti-Lyt 2.2 each destroyed a portion of the lymphocyte population responsible for MuIFN-gamma production. Kinetic analysis of production and release showed that IFN was detectable in culture fluids within 4 h after treatment with very little IFN remaining cell-associated (less than 10%). A simple, rapid, and economical two-step purification procedure involving ammonium sulfate fractionation and yeast RNA affinity chromatography resulted in as much as 770-fold purification to achieve specific activities greater than 10(7) u/mg protein. The purified MuIFN-gamma was shown to be predominantly acid-labile, inactivated by sodium dodecyl sulfate (SDS), and neutralized by antiserum to MuIFN-gamma. Approximately 10% of the MuIFN-gamma was acid-stable and SDS-resistant, but was still neutralized by anti-MuIFN-gamma serum. Two molecular weight peaks of about 40 and 20 kD were demonstrated by SDS-polyacrylamide gel electrophoresis. Isoelectric focusing in polyacrylamide slab gels gave a relatively heterogeneous band of activity between pH 5.5 and 6.5. The mechanism by which the combination treatment described enhances MuIFN-gamma production so markedly remains unknown, but the degree of enhancement is greater than additive.

Animals↗
PubMed1984

Diphtheria toxin receptor sites on membranes of cultured cells and erythrocytes demonstrated by fluorescence and electron microscopy.

Diphtheria toxin (DT) receptor sites were identified on cell membranes by indirect immunofluorescence and immunoferritin labelling. The results obtained were correlated (1) with the binding of 125I-labelled DT (to the very same cell populations used in the ultrastructural studies), and (2) with toxin sensitivity as shown by inhibition of 14C-amino acid incorporation into protein. Binding and immunocytochemical studies were carried out at 0 degrees C to preclude internalization of DT. Receptor sites for DT were observed on functionally responsive, cultured human diploid (BUD-8) fibroblasts as well as on a small fraction of erythrocytes (RBC) of DT-susceptible species, i.e. human and sheep. On all BUD-8 cell sections DT receptor sites were located in annular patches and not on microvilli as had been observed in the KB epithelial cell line. Immunoferritin label was revealed on only 10% +/- 2.5 (SD) of human RBC in discreet loci along the cell membrane. Specificity of binding of DT to human fibroblast and RBC receptor sites was further demonstrated by competition between 125I-labeled and non-labelled DT. There was no specific binding to DT-treated cultured mouse L929 fibroblasts or to RBC of mouse of rat, species resistant to the toxin. Thus, direct ultrastructural immunocytochemical evidence is provided for the presence of specific cellular DT receptors on cultured cells and erythrocytes of species sensitive to DT, but not on those of species resistant to DT.

Animals↗
PubMed1983

Leucine catabolism during the differentiation of 3T3-L1 cells. Expression of a mitochondrial enzyme system.

Leucine can be utilized efficiently as a precursor for lipid biosynthesis by adipose tissue, especially in the presence of glucose or glucose and insulin. During the differentiation of 3T3-L1 fibroblasts to adipocytes, the rate of lipid biosynthesis from L-[U-14C]leucine increases at least 30-fold and lipogenesis, with [U-14C] acetate as the precursor, increases by 10- to 15-fold. The specific activities of two mitochondrial dehydrogenases in the leucine oxidative pathway, the branched chain alpha-ketoacid dehydrogenase and isovaleryl-CoA dehydrogenase, as well as of leucine:alpha-ketoglutarate transaminase, increase at least 20-fold during the adipose conversion. Isovaleryl-CoA dehydrogenase was assayed in crude extracts using a specific fluorimetric method employing electron transfer flavoprotein as the electron acceptor for the flavoprotein dehydrogenase. The specific activity of 3-hydroxy-3-methylglutaryl-CoA lyase, the mitochondrial enzyme catalyzing the terminal reaction in the leucine degradation pathway, increases 4-fold during differentiation. The increases in the specific activities of the mitochondrial enzymes occur without a change in the specific activity of cytochrome oxidase, indicating that the increases do not simply reflect proliferation of mitochondria. The biosynthesis of at least 20 soluble mitochondrial polypeptides is enhanced during the adipose conversion of the fibroblasts as determined by polyacrylamide gel electrophoresis following incubation of the cells with [35S] methionine. The results provide a conservative estimate of the extent of changes in mitochondrial soluble proteins during the adipose conversion. They also establish that differentiated 3T3-L1 adipocytes metabolize leucine like mature adipose tissue and illustrate the roles of the branched chain alpha-ketoacid dehydrogenase and isovaleryl-CoA dehydrogenase in lipogenesis.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1983

A unique set of polypeptides is induced by gamma interferon in addition to those induced in common with alpha and beta interferons.

Human immune interferon (IFN-gamma) differs from leukocyte interferon (IFN-alpha) and fibroblast interferon (IFN-beta) in cell origin, inducing agents, physical and biological properties and amino acid sequence. These differences have led to interest in possible differences in the biological properties of IFN-gamma compared with IFN-alpha and IFN-beta. IFN-gamma has the same broad range of biochemical and biological actions as do IFN-alpha and IFN-beta, although relative potencies vary depending on the cell type and function investigated. There has so far been no direct evidence that IFN-gamma alters normal cell functions differently from other interferons. We report here striking qualitative and quantitative differences in the intracellular response of human fibroblasts to IFN-gamma compared with IFN-alpha and IFN-beta. Two-dimensional gel electrophoresis demonstrates, in addition to the induction of a common group of polypeptides, the existence of a set of polypeptides whose synthesis is uniquely induced by IFN-gamma.

Cell Line↗
PubMed1983

Interferon and antibody titrations using haemagglutinating Togaviridae and trypsinized human erythrocytes.

Several Togaviridae of the alphavirus and flavivirus genera agglutinate trypsinized human group O erythrocytes (THOE) (Shortridge and Hu, 1976). Haemagglutinin titers of Semliki Forest virus (SFV) and Japanese encephalitis virus (JEV) measured with THOE were equivalent to, if not higher than, those obtained with Embden gander erythrocytes, even with unextracted haemagglutinin. Results obtained with THOE in JEV haemagglutination-inhibition tests on sera taken from a previously infected individual over a 20-yr period were similar to those measured during the initial JEV infection. The inhibition of SFV haemagglutinin production as measured with THOE was a very sensitive bioassay for chicken interferon: interferon titers were 6- to 10-fold higher than those obtained with the vesicular stomatitis virus plaque-reduction method. The generally greater availability of human erythrocytes (including those stabilized with glutaraldehyde), the simplicity of the trypsin treatment, and the possibility of using unextracted haemagglutinin recommend this technique for use with haemagglutinating Togaviridae.

ABO Blood-Group System↗
PubMed1983

Ultrastructural distribution of interferon receptor sites on mouse L fibroblasts grown in suspension: ganglioside blockade of ligand binding.

Murine beta-interferon (IFN) receptors on L929 cells grown in suspension culture were visualized by indirect immunoferritin electron microscopy. Ferritin label on these cells was associated primarily with the coated areas and coated pits of the membrane, in contrast to previous observations with L929 cells grown in a monolayer, which did not reveal such coated areas or pits but showed ferritin label distributed randomly on the cell membrane (Kushnaryov et al., Infect. Immun. 36:811-821, 1982). On about 15% of the cell sections from suspension-grown cells, the ferritin label was found outside coated membrane areas. These findings suggest that different cell populations exist with respect to the localization and possibly the affinity of IFN receptors. In the same experiment, exogenously added gangliosides blocked the binding to cell surfaces not only of 125I-labeled IFN but also of unlabeled IFN as revealed by an immunospecific ferritin labeling technique, providing direct evidence that gangliosides interfere with the binding of IFN to specific receptor sites on the surface of mouse L929 cells. These studies establish that the binding of IFN to cell membranes, depending on cell growth conditions, can involve coated areas and coated pits, to which certain hormones and toxins have been shown to bind.

Animals↗
PubMed1982

Ultrastructural localization of interferon receptors on the surfaces of cultured cells and erythrocytes.

The bindings sites for interferon (IFN) on the limiting cell membranes of human and mouse fibroblasts and erythrocytes were revealed by an indirect immunoferritin technique. Mouse IFN-beta and human IFN-beta of high specific activity were used with the corresponding purified antibodies. Species-specific IFN binding was demonstrated by ferritin deposition on human erythrocytes and fibroblast membranes treated with human IFN and on mouse erythrocytes and fibroblast membranes treated with mouse IFN, but not on human erythrocytes or fibroblast membranes treated with mouse IFN. IFN binding sites on fibroblasts were located on regions of membranes between microvilli, whereas diphtheria toxin receptors were demonstrated mainly on microvilli. IFN binding altered the diphtheria toxin after IFN treatment. This reduced toxicity correlated with a decrease in the quantity of receptors for diphtheria toxin on the cell membrane. Thus, the species-specific binding of IFN appears to depend on membrane receptors in discrete regions of the limiting membrane which are present not only on functionally responsive fibroblasts but also on erythrocytes.

Animals↗