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B Y Rubin

Publications and source records attributed to B Y Rubin.

69 records · Page 4Linked to original sources
PubMed1983

Human interferon-alpha-and-gamma-mediated inhibition of retrovirus production in the absence of an inhibitory effect on vesicular stomatitis virus and encephalomyocarditis virus replication in RD-114 cells.

RD-114 line is a human sarcoma cell line chronically infected with RD-114 retrovirus. Treatment of these cells with increasing doses of human interferon-alpha or -gamma resulted in increasing inhibition of RD-114 virus production. Surprisingly, the replication of vesicular stomatitis virus and encephalomyocarditis virus, in these cells and in the parental RD cells which are not infected with the retrovirus, was insensitive to interferon treatment. Unlike reported differences in other properties of interferon-alpha and interferon-gamma, there were no differences in their antiretroviral properties such as dose response, kinetics of establishment of the antiretroviral state, and kinetics of its dissipation upon removal of interferon.

Dose-Response Relationship, Drug↗
PubMed1983

Human tumor necrosis factor produced by human B-cell lines: synergistic cytotoxic interaction with human interferon.

Human cell lines of hematopoietic origin were tested for production of tumor necrosis factor (TNF). B-cell lines transformed by Epstein-Barr virus release a factor (referred to as hTNF) that is cytotoxic for mouse L cells sensitive to mouse TNF but not for L cells resistant to mouse TNF. Exposure to 4 beta-phorbol 12 beta-myristate 13 alpha-acetate augmented production of hTNF. hTNF activity was not found in supernatants of cell lines of T-cell, monocytic, or promyelocytic origin. Partially purified hTNF has a molecular weight of approximately 70,000, has no interferon activity, is acid labile, is destroyed by heating at 70 degrees C for 1 hr, induces cross-resistance to mouse TNF in vitro, and causes hemorrhagic necrosis of Meth A mouse sarcoma in the standard in vivo mouse TNF assay. Tests with a panel of 23 human cancer cell lines showed that hTNF is cytotoxic for 7 cell lines, cytostatic for 5, and has no effect on 11. Comparative studies with human alpha, beta, and gamma interferons indicated that sensitivity to hTNF and interferon can be distinguished. Combined treatment with hTNF and alpha or gamma interferon resulted in a synergistic cytotoxic effect.

Animals↗
PubMed1983

Antiviral, anticellular and enzyme-inducing activities of interferons in RD-114 cells.

RD-114 is a human sarcoma-derived cell line which is chronically infected with the RD-114 retrovirus. In a previous study, we found that treatment of these cells with human interferon-alpha or human interferon-gamma causes a marked inhibition of RD-114 virus production, but that the replication of exogenous vesicular stomatitis or encephalomyocarditis virus is not impaired. In the present study, we report that neither type of interferon has strong inhibitory effects on DNA synthesis or on multiplication of the cells. We also failed to detect a double-stranded RNA-dependent protein kinase activity in extracts of both interferon-treated and untreated cells. However, a low level of 2',5'-oligoadenylate [2,5(A)] synthetase activity was detectable in extracts of interferon-treated cells. 2,5(A)-dependent endonuclease L activity was detectable in extracts of both untreated and interferon-treated cells. This was probably responsible for the inhibition of protein synthesis observed upon introduction of 2,5(A) to RD-114 cells. In many cells, interferon has been found to induce synthesis of several proteins demonstrable by autoradiographic analysis of slab gels on which extracts of interferon-treated and radiolabelled cells are separated. Using a similar method, no such induced protein synthesis was detectable in interferon-treated RD-114 cells. Our results indicate that RD-114 cells are resistant to most known actions of interferons except for the antiretroviral action to which they are as sensitive as any other cell line.

2',5'-Oligoadenylate Synthetase↗
PubMed1983

Comparative antiproliferative efficacies of human alpha and gamma interferons.

The cell growth inhibitory efficacies of preparations of human alpha and gamma interferons (IFNs) have been tested on a variety of human cell lines. Human IFN-gamma was found to be more effective at inhibiting the growth of HeLa and U-amnion cells than was human IFN-alpha. The Daudi cell line, on the other hand, which exhibits a strong anticellular effect in response to treatment with human IFN-alpha, was found to be relatively insensitive to the anticellular effect of human IFN-gamma, as were a variety of other lymphoid cell lines. The inability of the IFN-gamma to inhibit the growth of the Daudi cells is paralleled by its inability to induce the synthesis of proteins observed to be synthesized in these cells in response to IFN-alpha.

Amnion↗
PubMed1983

Killing of intracellular Leishmania donovani by lymphokine-stimulated human mononuclear phagocytes. Evidence that interferon-gamma is the activating lymphokine.

We have found that the crude lymphokines, which prime the human monocyte-derived macrophage to generate H2O2 and exert microbicidal activity against intracellular Leishmania donovani, are rich in interferon (IFN)-gamma (600-3,000 U/ml). To determine the role of this specific lymphocyte product in macrophage activation, lymphokines were pretreated with a monoclonal antibody that neutralizes human IFN-gamma. Antibody exposure completely abolished the capacity of both mitogen- and antigen-stimulated lymphokines to either enhance macrophage H2O2 release or induce leishmanicidal activity. In addition, partially purified and pure recombinant human IFN-gamma were as effective as crude lymphokines in activating macrophages, and 3 d of treatment with 300 U/ml resulted in a seven- to eightfold increase in H2O2 generation and the intracellular killing of both L. donovani promastigotes and amastigotes. The ability of crude lymphokines to induce monocytes and macrophages from a patient with chronic granulomatous disease to kill L. donovani promastigotes was similarly abrogated by anti-IFN-gamma antibody, and could also be achieved by IFN-gamma alone. These results suggest that IFN-gamma is the key macrophage-activating molecule present within human lymphokines, and indicate that IFN-gamma can enhance both the oxygen-dependent and -independent antiprotozoal mechanisms of human mononuclear phagocytes.

Antibodies↗
PubMed1983

Comparative analysis of the influences of human gamma, alpha and beta interferons on human multipotential (CFU-GEMM), erythroid (BFU-E) and granulocyte-macrophage (CFU-GM) progenitor cells.

Preparations of human interferon (HuIFN) immune (gamma) (2 X 10(7) units/mg protein), HuIFN leukocyte (alpha) (1.4 X 10(8) units/mg protein) and HuIFN fibroblasts (beta) (10(6) U/mg protein) were assessed for their influence on colony formation of human hematopoietic progenitor cells: colony forming unit-granulocyte, erythroid, macrophage, megakaryocyte (CFU-GEMM), burst forming unit-erythroid (BFU-E), day 7 colony forming unit granulocyte-macrophage (CFU-GM) and day 14 CFU-GM. Colony formation by CFU-GEMM and BFU-E was suppressed equally by the three preparations of HuIFN, but colony formation by CFU-GM was suppressed differentially. CFU-GM were, on the whole, more responsive to HuIFN gamma than HuIFN alpha, and HuIFN beta was least effective. HuIFN alpha, but not HuIFN gamma or HuIFN beta, suppressed colony formation from CFU-GM without also suppressing the total number of colonies plus clusters. This was due to an increase in the numbers of clusters formed in the presence of HuIFN alpha. The suppressive influence on colonies from CFU-GM by the preparations of HuIFN and the enhancement of clusters by HuIFN alpha was apparently equal for colonies and clusters of neutrophils, eosinophils, macrophages and neutrophils plus macrophages. The suppressive effects of HuIFN gamma were inactivated by a monoclonal antibody to HuIFN gamma and the suppressive and enhancing effects of HuIFN alpha were inactivated with a heteroantiserum to HuIFN alpha. Depletion of monocytes, T lymphocytes and B lymphocytes from the target bone marrow cells had no influence on the effects of the preparations of HuIFN. These results demonstrate that the effects of HuIFN gamma and HuIFN alpha are due to the HuIFN themselves and that these actions on the hematopoietic progenitor cells are probably not mediated through monocytes and/or lymphocytes.

Antibodies, Monoclonal↗
PubMed1983

Gamma-interferon is the factor in lymphokine that activates human macrophages to inhibit intracellular Chlamydia psittaci replication.

We have demonstrated previously that mitogen-induced lymphokines activate human monocyte-derived macrophages to inhibit the intracellular replication of Chlamydia psittaci. To identify the factor(s) in crude lymphokines responsible for this antimicrobial effect, we tested human Con A-induced lymphokines for interferon activity. We also attempted to neutralize the lymphokines with a monoclonal antibody directed against human gamma-interferon and examined the ability of partially purified human gamma-interferon to induce macrophage antichlamydial activity. The lymphokine-induced antichlamydial effect was measured by the inhibition of chlamydial inclusion formation in Giemsa-stained macrophage cultures. Our lymphokines were found to be rich in gamma-interferon; treatment of cells for 48 hr before infection with lymphokines containing 300 U/ml of interferon resulted in an 89% inhibition of chlamydial growth. This lymphokine effect was completely abolished by monoclonal antibody against human gamma-interferon, but not by antisera against human alpha- or beta-interferons. In addition, partially purified human gamma-interferon alone induced macrophages to restrict chlamydial growth by 95%. We conclude that it is the gamma-interferon present in human Con A-induced lymphokines that activates monocyte-derived macrophages to inhibit chlamydial replication.

Antibodies, Monoclonal↗
PubMed1983

Lymphokine inducing "terminal differentiation" of the human monoblast leukemia line U937: a role for gamma interferon.

The human monoblast leukemia line, U937, is growth-inhibited and induced to develop markers of mature monocytes by lymphokine preparations. Lymphokine is cytostatic and induces expression of Fc receptors in U937 and in myelomonocytic leukemic lines RC-2A and KG-1, but does not have these effects on T- and B-lymphocytic lines. In addition to previously described properties, including complement receptors, phagocytosis, and antibody-dependent cellular cytotoxicity (ADCC), Mac-1 and Mac-3 surface antigens defined by monoclonal antibodies are induced on U937 cells by lymphokine and phorbol ester. The Mac-1 surface component appears to have a regulatory role in differentiation of the monocyte lineage line, since antibodies to this antigen block the induction of Mac-3 antigen. The lymphokine activity was concentrated by salt precipitation and characterized by ion-exchange and size chromatography. Fractions of about 40,000 daltons were responsible for growth inhibition and induction of Fc receptors and Mac-1 antigen in U937 cells. However, ADCC was not induced in U937 by individual fractions of lymphokine, suggesting that this cytotoxic capacity may be regulated by a lymphokine of a different size, which is only effective after initial maturation steps. Since gamma-interferon is present on the 40K size range of lymphokine, the possibility that interferon is a differentiation modulator for the monoblast cells was investigated. Highly purified gamma-interferon (10(7) U/mg protein) at 10-300 U/ml inhibited growth and induced Fc receptors in U937 similar to the effect of lymphokine. The Fc-receptor-inducing activity of lymphokine was inhibited by a neutralizing monoclonal antibody to gamma-interferon, suggesting that this differentiation factor in lymphokine is gamma-interferon.

Animals↗
PubMed1980

Differential efficacies of human type I and type II interferons as antiviral and antiproliferative agents.

Treatment of human fibroblast FS-4 cultures with human type II interferon preparations induced the synthesis of at least four proteins that were similar in size to four of the five proteins induced by type I interferons (Mr 120,000, 88,000, 67,000, and 56,000). However, the Mr 67,000 and 56,000 proteins were induced more strongly by type II than by type I interferon, and a counterpart of a Mr 80,000 protein induced by type I interferons was not noticeably induced by type II interferon preparations. We therefore compared type I and type II interferons for relative antiviral activities against different viruses (vesicular stomatitis, encephalomyocarditis, and vaccinia viruses and reovirus) and for cell growth-inhibitory activities on various cell types. The replication of vesicular stomatitis and encephalomyocarditis viruses was inhibited more strongly by type I interferon, whereas reovirus and vaccinia virus showed greater sensitivity to type II interferon preparations. This indicates that viruses may differ in their sensitivity to human type I and type II interferons and that the antiviral mechanisms induced by type I and type II interferons may have significant differences. The type I and type II interferons may have significant differences. The type I and type II interferons may also differ in their efficacies as antiproliferative agents. Type II interferon preparations at 2.5 units/ml inhibited the incorporatin of [3H]thymidine to a greater extent than did type I interferon at 400 units/ml. (For both type I and type II interferons, the unit of interferon activity was defined as the concentration that decreased the yield of vesicular stomatitis virus by 50% in FS-4 cultures.) Furthermore, whereas type II interferon preparations had a reversible cytostatic effect on normal human fibroblasts at 10 units/ml, the transformed cells tested (HeLa, osteosarcoma, U-amnion) showed extensive cell death, thus indicating that it may have a cytocidal effect on certain tumor cells. It appears that human type II interferon (or a factor present in these preparations) may be a potent antitumor agent.

Cell Division↗
PubMed1980

Interferon-induced proteins in human fibroblasts and development of the antiviral state.

Treatment of human fibroblasts with interferon induces the synthesis of several proteins, as detected by incorporation of [35S]methionine followed by analysis of cell extracts by polyacrylamide gel electrophoresis. The induction of these proteins had features in common with the development of the antiviral effect of interferon, such as (i) sensitivity to actinomycin D and cycloheximide when these compounds were added together with interferon, (ii) insensitivity to actinomycin D if the actinomycin D was added 2 h after the addition of interferon, (iii) similar dependence on interferon concentration, and (iv) species specificity for interferon. When interferon treatment was given in the presence of cycloheximide and actinomycin D was added before the removal of cycloheximide, all four proteins were induced, thus suggesting that their inductions are coordinated. Labeling for 2-h periods at varying time intervals after the addition of interferon revealed that the synthesis of these proteins was induced within a few hours, peaked at different time intervals, and was soon followed by a marked decline, suggesting that the mRNA's for these proteins have short half-lives. Moreover, this decline occurred despite the fact that the cells were continuously exposed to interferon, and there was no measurable loss of interferon activity in the medium. This suggests that the induction of these proteins is transient and is apparently subject to further control.

Cell Line↗
PubMed1979

Interferon action: induction of specific proteins in mouse and human cells by homologous interferons.

Treatment of mouse (Ehrlich ascites tumor and L929) and human (FS4, GM258, etc.) cells with homologous interferons results in the induction of several proteins. Extracts obtained from cells labeled with [35S]methionine in the absence or presence of interferon were fractionated on poly(I) . poly(C)-agarose columns. The proteins retained on the columns revealed, upon sodium dodecyl sulfate/polyacrylamide gel electrophoresis, three protein bands in mouse cells (Mr 120,000; 80,000; and 67,000) and two in human cells (Mr 120,000 and 80,000) which were detected in the extracts of interferon-treated but not of untreated cells. These proteins were retained on double-stranded RNA [poly(I) . poly(C)-agarose] columns but very poorly, if at all, on single-stranded RNA [poly(I)- or poly(C)-agarose] columns, suggesting that they have an affinity for double-stranded RNA. In addition, interferon treatment of human fibroblasts greatly increased the labeling of three other protein bands (Mr 88,000; 67,000; and 56,000) which were detected in whole extracts but were not appreciably retained on poly(I) . poly(C)-agarose columns. The appearance of the induced proteins was blocked by actinomycin D if added together with interferon, indicating that transcription of certain genetic information is required. The possible correlation between the induced proteins described here and the elevated levels of certain enzymes in interferon-treated cells (a protein kinase and 2'-5'-oligoadenylate synthetase) is at present unclear.

Animals↗
PubMed1978

Detection of aberrant nuclear DNA metabolism in a conditional mutant of Saccharomyces cerevisiae.

A single recessive nuclear gene mutation has been isolated from strain 123.1C of Saccharomyces cerevisiae which appears to be conditionally deficient in nuclear DNA metabolism. Growth of the mutant strain at the elevated temperature of 36 degree C results in rapid loss of cell viability. However, no apparent reduction in the rate of radioisotope incorporation into DNA was detected during this period. When haploid cells carrying this temperature sensitive lesion were exposed to the restrictive temperature for varying lengths of time, returned to the permissive temperature, mated with a non-temperature sensitive strain and then the resulting diploids made to undergo meiosis, a greatly reduced number of viable spores were produced. Genetic analysis of the viable spores produced by these diploids has revealed aberrant auxotrophic marker segregation patterns. Thus, these results suggest that the mutated gene hardbored in this strain plays a vital role in the metabolism of the nuclear genome.

DNA↗
PubMed1977

Regulation of yeast mitochondrial DNA synthesis. I. Analysis of a mutant conditionally deficient in mitochondrial DNA metabolism.

A single nuclear gene mutation has been isolated from strain 123.1C of Saccharomyces cerevisiae which is conditionally deficient in mitochondrial DNA metabolism. Growth of the haploid in media containing dextrose, a repressing carbon source, at 36 degrees C causes the rapid cessation of mitochondrial DNA synthesis as analyzed by radioactive 3H-adenine incorporation into mitochondrial DNA. These cells continue to grow and divide giving rise to neutral petites which are devoid of mitochondrial DNA as measured by radioactive incorporation of 3H-adenine at the permissive temperature. Growth of the haploid cells in media containing glycerol, a non-repressing carbon source, at 36 degrees C does not prevent mitochondrial DNA synthesis, however, the population of cells becomes partially petite. When such petites are analyzed, they are found to be suppressive and to contain mitochondrial DNA as measured in the manner described above. The action of this mutated gene appears to involve the sunthetic aspects of mitochondrial DNA metabolism, as haploid cells prelabeled in dextrose media with 3H-adenine show no loss or degradation of mitochondrial DNA at the restrictive temperature of 36 degrees C.

Cold Temperature↗