Effect of verapamil on interferon production, mastocyte degranulation and histamine release--studies in mice sensitized with ovalbumin

The effect of verapamil, calcium antagonist, on the IFN production, the histamine release and degranulation of mastocytes were studied. The mastocytes were harvested from mice sensitized with ovalbumin, treated with verapamil and induced with Newcastle virus (NDV) to the interferon production (IFN). It has been shown that the percentage of degranulation was lower in mastocytes of the mice treated with verapamil, both induced with NDV and non-induced ones. The titer of interferon was lower when the mice induced with virus were injected with verapamil. The inhibitory effect of this drug on histamine release has only been found on the 8th day after the sensitization.     

Comparative study of the interferon-inducing capacity of Newcastle disease and Sendai viruses in human and animal bone marrow cells

Sendai and Newcastle disease virus (NDV) induced high and approximately similar interferon production in bone marrow cells of man, rats, and mice. In contrast to NDV, Sendai virus induced no interferon production in chick bone marrow cells. Interferon production by the bone marrow cells did not differ in its time course and requirements from production of leukocyte interferon.     

Interferon induction by viruses and polynucleotides: a differential effect of comptothecin.

The plant alkaloid comptothecin inhibits interferon production induced by Newcastle disease virus (NDV) or ultraviolet-irradiated NDV in chick and human cells, and by Sindbis virus in chick cells. It has no effect on interferon production induced by poly (rI).poly(rC) in chick and human cells. No effect of comptothecin could be detected on the multiplication of NDV, and it is concluded that the inhibition reflects a difference between interferon induction by viruses and by polynucleotides.     

Effect of thymosin on interferon production and antiviral resistance in mice

The 5th and 6th fractions of thymosin, a hormone of the thymus gland, stimulated interferon production both in vivo (experiments in white and CBA mice) and in vitro in CBA mouse splenocytes when different interferon inducers were used (phage dsRNA, poly(G): poly(C), NDV, and mitogens). The highest stimulating effect in vivo was observed with interferon induction 6-8 hours after thymosin administration. An increase in production of both alpha/beta and gamma interferons under the influence of thymosin was observed. Thymosin alone induced no interferon synthesis.     

The enhancement of interferon production by endotoxin

Summary Pretreatment of bovine leukocyte cultures with endotoxin enhanced interferon production by Newcastle disease virus (NDV) as evidenced by an early and high rate of interferon production. This enhancing effect was greatest when NDV was inoculated at three hours after endotoxin treatment. It was blocked by actinomycin D both before and after the addition of endotoxin. Propagation of NDV was less marked in endotoxin-treated cultures than in untreated control cultures. Pretreatment with endotoxin interfered with the cytopathic effect of the NDV on the cultured cells.     

The effect of various inducers on interferon-synthesizing activity of leukocytes in patients with diabetes mellitus

The results of the study of interferon response of leukocytes in patients with diabetes mellitus (DM) with three inducers: Newcastle disease virus (NDV), poludan, and dipyridamole are presented. Different patterns of interferon production in patients with DM and normal subjects were shown. Dipyridamole and NDV induced high interferon levels in patients with DM which allow it to be recommended as an additional therapeutic means.     

Interferon synthesis by peripheral blood leukocytes of patients with bronchial asthma

Interferon production by leukocytes of 28 bronchial asthma patients and 27 normal subjects was examined using whole blood technique. Interferon production in blood samples was induced by classical inducers and the obtained interferons were tested in A549 cells using EMC virus as challenge. Leukocytes from both atopic and infectious asthma patients showed decreased ability to interferon production in comparison to healthy donors. In atopic asthma statistically significant differences in interferon production induced by NDV, PHA + PMA and LPS were observed. In the case of infectious asthma lower amounts of interferon were noted after stimulation with LPS and PHA + PMA. A decrease in spontaneous interferon production was also observed.     

The influence of immunization on the production of interferon in vivo and in vitro.

The present study was undertaken to compare the production of interferon by immunized mice in response to different viral inducers. Porton mice were immunized with NDV or A/Wr11/57 virus by injecting 6-week-old animals with virus on days 1, 7, and 14. The interferon response was investigated 3 weeks later. Compared with controls, the A-immunized mice after stimulation in vivo, produced more interferon when NDV was used as inducer. It was shown in sera as well as in washings of peritoneal cells. In experiments in vitro induction of interferon with NDV or A/Wr11/57 virus in macrophages of immunized mice resulted in significant rise in interferon levels. These results are in agreement with earlier investigation of others and support the role of immune recognition in the interferon response.     

The interferon system in ducks infected with viral hepatitis B

The duck peripheral blood lymphocytes and spleen cells were shown to be relatively resistant to interferon induction by viral (NDV) and nonviral (dsRNA) inducers as well as to Con A induction of gamma-interferon. The concentration of the inducers had to be increased 4-5-fold to induce interferon production. Charry valley ducks produced more alpha-interferon than Peking ducks. The level of interferon production induced by NDV and dsRNA (Ridostin) was similar in DHBV-positive Peking ducks and in the control group, but in the infected Charry valley ducks interferon production was lower than in the controls (224 to 180 U/0.1 ml in NDV-induced and from 192 to 43.3 U/0.1 ml in dsRNA-induced). Early bursectomy brought down the interferon production in non-infected ducts, but in DHBV-positive bursectomized ducks (Y) the level of interferon was higher than in the control bursectomized ducks.     

Suppression of interferon production in mouse spleen cells by cytochalasin D.

Cytochalasin D is thought to impair microfilament function. The present study has investigated its effects on four different systems in which interferon is formed, namely (1) mouse fibroblasts induced with virus (2) mouse spleen cells induced with virus, or (3) with endotoxin or (4) by allogeneic stimulation. Cytochalasin D did not suppress formation of interferon by fibroblasts (L cells) or spleen cells stimulated with either HVJ or NDV. However it did suppress production of interferon by spleen cells in response to endotoxin or an allogeneic stimulation; here its action was apparently not on the secretion of interferon, but on some earlier event. It also suppressed the production of interferon by mouse spleen cells induced with HVJ if this had been u.v. irradiated for more than 15 min: this suggests that cytochalasin D sensitive structures do play some role in interferon production by mouse spleen cells when stimulated with HVJ, as well as when they are stimulated with endotoxin or an allogeneic stimulus.     

Interferon induction with Newcastle disease virus in FS-4 cells: Effect of 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB)

Summary DRB is an inhibitor of heterogeneous nuclear RNA (hnRNA) and messenger RNA (mRNA) synthesis. The effect of DRB on interferon production stimulated by Newcastle disease virus (NDV) in the human FS-4 cells was studied. Interferon production in cells primed by treatment with interferon was markedly enhanced (superinduced) in the presence of DRB. This superinduction was essentially due to an inhibition of the rapid decline (shutoff) of interferon production observed in primed cells not treated with DRB. Continuous presence of DRB was required for maximal superinduction. In this and other respects the interferon response induced by NDV in primed cells resembled poly(I) · poly(C)-induced interferon production. In contrast interferon production in cells not primed with interferon was virtually abolished by DRB treatment. Since neither virus specific RNA synthesis nor virus replication were significantly affected by DRB, the inhibition of interferon production is likely to result from the inhibitory action of DRB on a cellular, rather than viral, function. Apparently some differences exist in the synthesis or processing of the mRNAs for interferons in primed and unprimed cells and these determine the different sensitivities of these two responses to DRB.With 2 Figures     

Induction of interferon by temperature-sensitive mutants of Newcastle disease virus

Spontaneously-selected and mutagen-induced temperature-sensitive (ts) mutants of Newcastle disease virus (NDV) were used to study interferon induction in chick embryo (CE) cells at temperatures permissive (37°) and nonpermissive (42°) for virus replication. Both infectious and UV-irradiated virus were tested for interferon-inducing ability in cells pretreated or not pretreated with homologous interferon. At 37°, only UV-irradiated NDV was capable of inducing interferon in cells not treated with interferon before infection. In cells pretreated with interferon, on the other hand, both unirradiated and UV-irradiated virus stimulated the production of interferon. At 42°, the interferon-inducing phenotype for some UV-irradiated ts mutants was dependent on whether or not cells were pretreated with interferon. For example, out of 10 mutants examined, one UV-irradiated ts mutant induced interferon in both untreated and interferon pretreated cells; 7 mutants failed to induce in untreated cells but induced from 25–100% of the wild-type level of interferon in cells pretreated with interferon; and two mutants failed to induce interferon in both types of cells. In addition, one mutant (NDV₀ts-100) induced low or undetectable levels of interferon at both 37° and 42°, conditions under which wild-type virus (NDV₀) produced significant levels of interferon. Co-infection of cells with UV-irradiated ts-100 and a preparation of NDV₀ exposed to prolonged irradiation resulted in considerable production of interferon. These results suggest the possibility that more than one virus function may be involved in interferon induction by NDV in CE cells.     

Interferon-hyporesponsiveness in mice in connection with dose interval and site of administration of Newcastle disease virus. Reflexion in serum complement levels.

Intraperitoneal administration of Newcastle disease virus (NDV) resulted in enhanced serum levels of complement not accompanied by an increase of interferon levels, when measured at 24 hours' intervals. On the other hand, intravenous injection of NDV caused a drop of complement levels of short duration with an accompanying increase of interferon levels. Hyporeactivity to induction of serum interferon could not be achieved by intraperitoneal administration of NDV, but an incomplete hyporeactivity could be achieved by intravenous administration of NDV. It might be assumed that production of interferon in mice occurs in different separated compartments depending on the route of inoculation of the inducer.     

Distinguishing characteristics of interferon induction with poly(I)-poly(C) and Newcastle disease virus in human cells.

Exposure of a human diploid foreskin cell strain (FS-4) to polyinosinate-polycytidylate [poly(I)·poly(C)] resulted in an early rise of interferon production that peaked at about 4 hr after induction and decreased rapidly thereafter. Irradiation of cells with low to moderate doses of ultraviolet (uv) light immediately before induction with poly(I)·poly(C) increased the amount of interferon produced up to about tenfold. This enhancement was apparently due to interference with the shut-off process which in unirradiated cells leads to early termination of interferon production; in irradiated cells interferon production continued for much longer.Inoculation of FS-4 cells with Newcastle disease virus (NDV) resulted in interferon production that showed a slower rise and peaked only at about 10–15 hr after inoculation. Irradiation of cells at the time of induction with NDV resulted in a dose-dependent decrease of interferon production. However, a small fraction of the total amount of interferon produced in response to NDV, which appeared by about 5 hr after virus inoculation, was resistant to uv. This uv-resistant early peak of NDV-induced interferon was greatly enhanced in cells which 6 hr before virus inoculation had either been induced with poly(I)·poly(C) or incubated with interferon, while the appearance of the major, uv-sensitive peak of NDV-induced interferon was inhibited or delayed after the same treatments. In its characteristics the early peak of NDV-induced interferon resembled the poly(I)·poly(C)-induced interferon response. Poly(I)·poly(C)-induced, as well as the early and late NDV-induced interferons were all neutralized by an antiserum raised against poly(I)·poly(C)-induced interferon, suggesting that they represent products of the same structural gene(s). It is concluded that there may be more than one mechanism of interferon induction by a single virus.     

Participation of cytophilic antibody in enhancement of interferon production in macrophages by under-neutralized NDV

Summary Enhancement of interferon production in mouse peritoneal macrophages by Newcastle disease virus (NDV) under-neutralized with whole antiserum or its IgG fraction was inhibited in cells pretreated with iodoacetamide, sodium nitrite or formaldehyde, which blocked adsorption of cytophilic antibody to macrophages. Mouse embryo primary culture cells had no receptor for cytophilic antibody, and in such a cell culture, under-neutralized NDV did not enhance interferon production. Antiserum enhanced interferon production by NDV which had adsorbed to cell surfaces, but did not affect NDV that had penetrated the cells.     

Mechanism of stimulation of natural killer-cell cytotoxicity by interferon and an interferon-inducer in the rat.

The interferon-induced Newcastle disease virus (NDV) was shown to augment cytotoxicity attributable to natural killer (NK) cells in all of the major lymphoid organs of W/Fu rats except the thymus. The levels of interferon isolated from the spleen following NDV inoculation correlated with the increase in splenic cytotoxicity from the same spleen. Spleen-derived interferon was shown to augment splenic cytotoxicity following intravenous inoculation, and to augment spleen cell cytotoxicity in vitro. Three major peaks of interferon type I were found in spleen homogenates corresponding to mol. wt of greater than 100,000, 29-33,000 and 19-23,000. All these fractions stimulated spleen cell cytotoxicity when tested in vitro. The rapid drop in splenic cytotoxicity 24 hr after NDV inoculation was associated with a rapid fall in interferon levels in vivo. The need for the continued presence of interferon for the stimulation of cytotoxicity was demonstrated when spleen cells pretreated with interferon for 4 hr in vitro lost their augmented cytotoxicity upon culturing for a further 20 hr in the absence of interferon. Although splenic cytotoxicity returned to control levels within 24 hr of a single 10(7.3) EID50 dose of NDV, repeated doses of NDV maintained augmented cytotoxicity over a longer period. Spleen cells either taken from rats injected with NDV or pretreated in vitro with interferon showed a two-fold increase in the number of cytotoxic cells bound to W/FuG-1 target cells, with no change in the target binding-cell numbers. However, only the cells pretreated with interferon showed an increase in lytic efficiency.     

Interferon production in Propionibacterium acnes treated mice

Interferonogenic properties of Propionibacterium acnes (PA) was studied in vivo and in vitro using CBA, BALB/c and 129AoBoy strains of mice. IFN was induced only in CBA strain after i.v. PA injection. BALB/c and 129AoBoy mice did not produce IFN. In the sera of CBA mice, obtained after i.p. injection of PA, interferon was not found. However, spleen cells of these mice produced IFN beginning from the 3rd day after injection. This interferon response lasted until the 10th week. Furthermore, in vivo studies showed enhancement effect of PA i.p. injection on IFN synthesis when NDV was introduced i.v. as inducer. The increased interferon level was also observed in the peritoneal cells isolated from PA--pretreated mice, induced in vitro with NDV or PA.     

Le interferon production by human fibroblasts.

Human leukocyte (Le) and fibroblast (F) interferons differ in antigenic properties, physicochemical characteristics, and activity on cells of heterologous species. Previous work from this laboratory showed that two human foreskin fibroblast strains can produce either F interferon alone or both F and Le interferons, depending on the nature of the inducer. The present study demonstrates that both the cell type and the inducer determine the proportion of Le interferon produced by human fibroblast strains. Of eight strains tested, the human GM-258 strain, which is trisomic for chromosome 21, produced the highest absolute and relative amounts of Le interferon after Newcastle disease virus (NDV) inoculation. However, there was no correlation between Le interferon production and number of copies of chromosome 21 in other cell strains examined. Although both NDV and vesicular stomatitis virus (VSV) induced a substantial proportion of Le interferon in GM-258 cells, little or no Le interferon was induced in the same cells by polyinosinic-polycytidylic acid (poly(I)·poly(C) under five different conditions. In GM-258 cells induced with NDV, it was possible to partially manipulate the relative proportion of F and Le interferons and the time at which they were made by altering the conditions of induction. The percentage of Le interferon was increased by decreasing the multiplicity of infection or irradiating the virus with ultraviolet light. Kinetics of F and Le interferon production after different modes of NDV inoculation paralleled each other closely. F and Le interferon production was inhibited to similar degrees in the presence of the glycosylation inhibitors 2-deoxy-d-glucose and d-glucosamine. The bovine EBTr cell strain was used for the selective assay of Le interferon. These cells were as sensitive to Le interferon as human diploid fibroblasts. In contrast, less than 0.1% of human F interferon activity crossed the species line in EBTr cells. Le and F interferons produced by NDV-induced GM-258 cells were physically separated by affinity chromatography on immobilized anti-Le and anti-F globulins. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the Le interferon component produced in GM-258 cells formed two separate peaks (with molecular weights of approximately 18,000 and 25,000), closely resembling a control Le interferon preparation. In contrast, the F interferon moiety made in GM-258 cells formed a single peak on SDS-PAGE, as did control F interferon (molecular weight approximately 26,000).     

Persistent Newcastle Disease Virus Infection in Embryonic Chicken Tracheal Organ Cultures

The persistent infection of embryonic chicken tracheal organ cultures with Newcastle disease virus (NDV) is described. Tracheal explants remained morphologically intact and were able to support the replication of NDV for 6 months. Peak titers of released virus occurred at 1 week postinfection, whereas maximal immunofluorescence was not observed until 30 days postinfection. The inoculum titer was not critical, and viral persistence resulted with either of two strains of NDV tested. Serum was not required in the medium for explant viability or to maintain the persistent infection. The presence of a contaminating virus morphologically resembling a leukovirus neither altered the course of infection nor affected the survivability of explants. Although interferon was not detected in the culture medium, persistently infected explants were resistant to heterologous viral challenge, and a similar resistant state could be induced in uninfected explants with exogenous interferon or ultraviolet light-inactivated NDV. No evidence was found to implicate antibody as a regulatory factor in the establishment or maintenance of persistence. The results from electron microscopy and immunofluorescence suggest the cells of the subepithelial connective tissue as the site of NDV persistence.