Cyclic AMP metabolism and interferon induction in mice after treatment with 10-carboxymethyl-9-acridanone

The low molecular weight substance 10-carboxymethyl-9-acridanone (CMA) is capable to induce interferon (IFN) production. In order to determine the effect of CMA on cyclic AMP alterations in relation to IFN production, male ABD2F1 hybrid mice were orally treated with several concentrations of CMA (400, 600 and 800 mg/kg) for varying periods of time up to 24 hr. IFN titres were detected as early as 3 and 4 hr, respectively, in mouse plasma after CMA administration, and their production continued for at least 24 hr. Maximum IFN titres were assayed in the presence of 800 mg/kg (3,200 IU/ml) CMA. Measuring of the intracellular concentrations of cyclic AMP in thymus and spleen revealed that in early stage (0.5 to 2 hr) CMA exhibited a dose dependent increase. The drug acted as an inhibitor of low Km cAMP phosphodiesterase in cell homogenates; a significantly enhanced enzyme activity (1 to 4 hr) was found after exposure to CMA in vivo.     

Competition of sodium salt of 9-oxo-10-acridineacetic acid with analogs during induction of interferon in the mouse bone marrow-derived macrophages

Analogs of 9-oxo-10-acridineacetic acid (CMA) including new synthetic compounds, were found to be valuable tools for investigating the mechanism of interferon (IFN) induction. Experiments were performed on the long-term cultures of mouse bone marrow-derived macrophages which are unusually susceptible to IFN induction by CMA. CMA in the optimal nontoxic concentration of 600 micrograms/ml may induce in the macrophages up to 3.500 units of IFN/ml. The response was found to be dose related. The analogs of CMA, compounds 3, 7-16, were found to be inactive as IFN inducers. However, the analogs 3, and 8-16 administered together with the suboptimal doses of CMA enhanced by 10 to 40-fold the interferon response to CMA. On the other hand, the compound 7 was shown to inhibit completely the induction of interferon by CMA. L-tryptophan was inactive as either enhancer or inhibitor of CMA. The mode of action of CMA is explained in terms of the hormonal concept of IFN induction.     

Blocking of interferon synthesis in murine macrophages by pretreatment with interferon

The influence of pretreatment with interferon (IFN) on subsequent IFN synthesis was investigated in macrophage cultures of DBA/2 and C57BL/6 mice. The doses of IFN alpha/beta for pretreatment ranged from 10,000 U/ml to 100 U/ml and the incubation time was between 18 and 2 h. No blocking effect was observed for chemical induction with poly I:poly C or CMA. However, for viral infection with NDV, blocking was observed. This inhibition of IFN synthesis was dependent on the dose and time of IFN pretreatment and of the titer of the inducing virus. Similarly in mouse fibroblast cultures no blocking activity was observed for induction with poly I:poly C/DEAE-dextran. Again, with NDV as inducer, pretreatment with IFN resulted in inhibition of interferon synthesis. Thus, our data show that blocking occurs only with a viral inducer and suggest that it is caused by an antiviral effect.     

Effects of plant transfer ribonucleic acids on interferon production

An optimal interferon (IFN) production was obtained at concentrations of 50 micrograms/ml poly I:C and 2000 micrograms/ml DEAE dextran in Lpa cells. It was shown that methionine initiator tRNA (tRNAiMet) in a dose 50 micrograms/ml or crude tRNA (tRNAc) applied to Lpa cell during the stages of IFN induction, IFN induction and synthesis, as well as during IFN synthesis resulted in a continuous IFN production for up to 24 hr. Exposure of the cells to 150 micrograms/ml tRNAiMet during the stages of IFN induction and IFN induction and synthesis caused total inhibition of IFN production. This effect was partially observed only after the high dose of tRNAc. Addition of a high dose of tRNAiMet or tRNAc to cells during the synthesis stage caused no inhibition but prolongation of IFN production.     

Induction of interferon in mice by sodium salt of 9-oxo-10-acridineacetic acid: specific enhancement by analogs

9-oxo-10-acridineacetic acid bearing the common name of 10-carboxymethyl-9-acridanone or CMA (6) was found to be a very potent interferon (IFN) inducer in adult Balb/c mice. Seven structural analogs of CMA were synthetized and assayed for the interferon inducing ability. Three of the compounds had new chemical structures. The analogs were shown to be either weak or inactive interferon inducers. However, some of the analogs administered intraperitoneally (i.p.) or orally (p.o.) either 2 h before CMA or together with the active inducer enhanced by 10 to 60-fold the serum interferon response. We suggest that CMA induces interferon indirectly via a specific protein receptor. The specific enhancement of the serum interferon response to CMA by its inactive analogs may be explained in terms of the competition of the compounds for binding sites at the acceptor or transporting protein molecules. In the presence of an analog of CMA greater amount of free CMA may be available for the receptors in the target cells than when CMA acts alone. Only CMA bound to the receptor would be biologically active whereas the complexes of the compounds with the acceptor are biologically inert.     

Correlation between Mutations in the Interferon Sensitivity-Determining Region of NS5A Protein and Viral Load of Hepatitis C Virus Subtypes 1b, 1c, and 2a

In the present study, we analyzed the possible relationship between interferon (IFN) sensitivity-determining region (ISDR) sequence variation of various hepatitis C virus (HCV) subtypes and serum HCV titers in Indonesian patients without IFN treatment. The viremia titers (mean +/- standard deviation) of HCV subtype 1b (HCV-1b) isolates with low (three or fewer) and high (four or more) numbers of ISDR mutations were 5.4 +/- 0.6 and 4.2 +/- 0.9 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Similarly, the viremia titers of HCV-1c isolates with low and high numbers of ISDR mutations were 5.3 +/- 0.6 and <3.0 +/- 0.0 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Also, the virus titers of HCV-2a isolates with low and high numbers of ISDR mutations were 4.3 +/- 0.7 and 3.5 +/- 0.4 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Thus, our results demonstrated that virus load in Indonesian patients infected with HCV-1b, HCV-1c, or HCV-2a correlated inversely with the number of mutations in the ISDR sequence, implying the possibility that the ISDR sequence plays an important role in determining the levels of HCV viremia.     

Cytopathic effect induced by rabies virus in McCoy cells.

Both fixed and street rabies virus when cultivated in McCoy cells caused cytopathic changes 24 to 72 h after infection, depending on the multiplicity of infection. The cytopathic effect (CPE) was easily recognizable and resembles that induced by other members of the Rhabdovirus group, such as vesicular stomatitis virus, in several cell cultures. Higher titers of the Pasteur strain (PV) of fixed rabies virus were found in supernatants of McCoy cells when compared to those in VERO cells. The virus titer increased with the number of passages attaining a high titer after three passages. Rabies antigens were detected by direct immunofluorescence labeling in most McCoy cells of the infected culture, and specific antibodies neutralized the virus growth and CPE. There was also inhibition by treatment of the cells with human interferon (HuIFN) -alpha or -gamma, but not by murine interferon (MuIFN) -alpha, -beta or -gamma. Rabies-infected McCoy cell cultures may provide a useful assay system, based on the induction of CPE, the high virus production and the sensitivity to IFN.     

Circulating interferon in the guinea pig infected with the XJ, prototype Junin virus strain

The interferon (IFN) induction capacity of the XJ prototype strain of Junín virus (JV) was investigated in the guinea pig model. Circulating alpha IFN was detected in 50% of the animals from days 2 to 9 postinfection (pi) and in 100% at day 11 pi, when all animals were in the premortem stage. Individual levels ranged from 20 to 1,280 guinea pig IFN units (GPIFNU)/ml. A correlation between XJ strain virulence and IFN titers was recorded. A possible role of IFN as a pathogenic factor in the outcome of the disease is discussed.     

Influence of L-tetramisole on the interferon production by mouse peritoneal and L929 cells.

The effect of L-tetramisole (Levamisole, Decaris) on the physiological interferon beta (INF beta) production by freshly isolated peritoneal cells of BALB/c, NZB and C3H mouse strains was studied. We have shown that these strains differ in their ability to produce physiological IFN. Peritoneal cells of individual BALB/c and NZB mice differed significantly in ability to produce the physiological IFN, but most of these animals are good producers, while the cells isolated from C3H mice are not. High concentrations of L-tetramisole (250 and 500 micrograms/ml) suppressed IFN synthesis in the cells from BALB/c and NZB mice. Lower concentration of L-tetramisole (125 micrograms/ml) inhibited the IFN production only partially and this effect was observed when the IFN production was high. When the IFN production was very low, L-tetramisole slightly increased the synthesis. L-tetramisole affected the production of the physiological IFN, but not the production of IFN induced by Newcastle disease virus (NDV) in the peritoneal cells of mice or in L929 cells.     

Effects of phorbol myristate acetate on interleukin-2 and accompanying interferon production of human leukocytes induced by heat-inactivated Staphylococcus aureus

Interleukin-2 (IL-2) production induced by heat--inactivated Staphylococcus aureus (SAU) was enhanced by simultaneous addition of phorbol myristate acetate (PMA). The effect was optimal at a concentration of 10 ng/ml SAU; in the presence of 10 ng/ml PMA, the amount of SAU required for maximal IL-2 production was lower. The kinetics of SAU and of SAU plus PMA-induced IL-2 production were similar. Stimulated mononuclear cells produced interferon (IFN) in addition to IL-2. The titre of accompanying IFN was decreased in cultures stimulated with the SAU plus PMA combination. Plastic nonadherent sheep erythrocyte-positive cells were the most active in the SAU-induced IL-2 production. In contrast, the bulk of the IFN activity was produced by the nonadherent E rosette-nonforming cells. Neutralization of IFN with specific antibodies and pH 2 treatment indicated that SAU-induced IFN consisted mainly of alpha-IFN.     

Induction of Interferon in Mice by Mycoplasmas

Interferon was induced in mice after intraperitoneal inoculation with four different mycoplasmas. Peak levels of between 100 and 300 U of interferon per ml were attained by 6 h postinfection with each of the mycoplasmas except Mycoplasma arthritidis, which induced higher titers (400 to 11,800 U/ml) by this time. A fifth mycoplasma, M. pulmonis, induced interferon inconsistently and at a later (72 to 96 h) time. Mycoplasmatales virus MVL51 and sterile mycoplasmal broth did not stimulate interferon production in vivo. All of the mycoplasmas and MVL51 failed to induce interferon in murine spleen cell, peritoneal exudate cell, or peripheral blood leukocyte cultures. Preinfecting the mycoplasmas with MVL51 or treating the organisms with trypsin or dilutions of specific antisera did not enhance their ability to induce interferon in vitro.     

参冬心宝口服液对柯萨奇病毒B3病毒性心肌炎小鼠的 …

目的 探讨参冬心宝口服液在小鼠体内免疫促进作用，为该药的临床应用提供理论依据。方法 以柯萨奇病毒Ｂ３型病毒感染１０日龄乳鼠为模型，观察了参冬心宝口服液对病毒感染急性期不同阶段心肌炎小鼠自然杀伤细胞活性及干扰素（ＩＦＮ）水平的影响。     

Induction of interferon after administration of a traditional Chinese medicine, xiao-chai-hu-tang (shosaiko-to).

We examined the ability of a traditional chinese herbal medicine, xiao-chai-hu-tang (Japanese name: shosaiko-to) to induce IFN in mice. A maximum activity (105 units/ml) of interferon (IFN) appeared in the serum of mice 16 h after intraperitoneal (i.p.) treatment with 250 mg/kg of shosaiko-to. Addition of polymyxin B did not abrogate the ability of shosaiko-to to induced serum IFN. The IFN was identified as IFN-alpha/beta by neutralizing test using anti-IFN alpha/beta antibodies. Pretreatment of mice with carrageenan suppressed the IFN induction by shosaiko-to, whereas the IFN induction by shosaiko-to was impaired neither in mice treated with anti-asialo-GM1 antibody nor in T-cell-deficient athymic nude mice. IFN was produced in vitro by spleen cells obtained from shosaiko-to treated mice. Moreover, spleen cells from untreated mice could also produce IFN when they were cultured with shosaiko-to. Additionally, serum IFN was also induced by the adoptive transfer of spleen cells from shosaiko-to treated mice to normal mice. On the other hand, peroral administration of shosaiko-to also induced IFN-alpha/beta in the serum. While IFN activity induced by i.p. administration of shosaiko-to declined after repeated treatments, the activity induced by its peroral administration did not decline during a long term treatment. These results showed that shosaiko-to is an IFN-alpha/beta inducer capable of repeated peroral administration.     

Interferon-inducing activity of dipyridamole in mice

The kinetics of interferon (IFN) production was studied in mice after intraperitoneal (i.p.) and oral administrations of dipyridamole. The substance showed a high IFN-inducing activity when given orally at single doses ranging from 12.5 to 100 mg/kg (1/21.5-1/172 of the single LD50 value): peak titres of 2048-4096 IU/ml in the blood serum were reached at 48 hr; elevated IFN levels persisted until day 5 after administration of the inducer. Significantly lower IFN titres were found after i.p. injection.     

Production and initial characterization of spotted souslik (Spermophilus suslicus) interferon

Spotted souslik (Spermophilus suslicus) interferon was induced in different cell cultures with two strains: Random (NDV-R) and Hertfordshire (NDV-H) of Newcastle disease virus. Both strains were good interferon inducers in cultures of lung cells (SL), kidney cells (SK) and embryo cells (SE). There were no significant differences in the amount of interferon produced in cells at different passage levels but the yield of interferon depended on the donor of cells. The highest interferon titers were produced 24h after infection of SK cells with NDV-R at multiplicity of infection 100 or .10 TCID50 per cell. UV-irradiation decreased the interferonogenic properties of NDV-R. Priming with 100 U/ml of 10 U/ml of homologous interferon significantly enhanced interferon production in souslik cells. However, the interferon concentrations higher than 100 U/ml caused a distinct inhibition in the subsequent interferon production ("blocking"). The pretreatment of cells with L-ascorbic acid slightly increases the yield of interferon produced in souslik cells after induction with NDV-H. Calcium chloride at nontoxic concentrations added together with the virus-inducer practically exhibited no effect on the interferon production in SL cells.     

Changes in antibody titers to hepatitis C virus following interferon therapy for chronic infection

The use of quantitative assays for hepatitis C virus specific antibodies (anti-HCV) as a prognostic marker was evaluated in 31 patients with chronic hepatitis C treated with interferon (IFN). Changes in titers of serum HCV-RNA and anti-HCV antibodies; anti-C11 (anti-core), anti-C100 (anti-NS3), and anti-C7 (anti-NS3) were investigated. Recombinant IFN-α 2a was administered and the patients were followed for more than 1 year. The patients were classified into three groups according to their responses to IFN: 11 sustained responders with continuous normalizations of serum alanine aminotransferase (ALT) levels; 14 transient responders with transient decreases in ALT; and six nonresponders who had no changes in ALT levels. Ten of 11 sustained responders had a continuous decrease in anti-C11 titers after completion of treatment, decreasing to less than half of pretreatment titers. No patients in the other two groups had a continuous decrease in anti-C11 titers. Although sustained responders had decreases in anti-C100 and anti-C7 titers after IFN therapy, these titers also decreased in some patients in the other two groups. HCV-RNA was not detected in the sera of 10 of 11 sustained responders following IFN therapy. In contrast, while 9 of 10 transient and nonresponders had a decrease or disappearance of HCV-RNA at the completion of therapy, they had increased levels thereafter. These results indicate that anti-HCV-core (anti-C11) titers most closely reflect the status of HCV replication. A quantitative assay for anti-HCV-core antibody can be used as a predictive marker of remission in IFN-treated patients with chronic hepatitis C. © 1994 Wiley-Liss, Inc.     

Interferon production by human mononuclear leukocytes: differences between respiratory syncytial virus and influenza viruses.

The ability of respiratory syncytial virus (RSV) to induce interferon production by human mononuclear leukocytes was compared with that of influenza viruses. Cell culture fluids were assayed for interferon activity 1, 3 and 7 days after exposure to RSV or to one of two subtypes of influenza A virus (H0N1 and H3N2). RSV induced interferon production inconsistently and in low titers. Varying the multiplicity of infection did not improve the ability of RSV to induce interferon production. In contrast, influenza viruses were effective inducers of interferon production. Seropositivity to the influenza virus strains was not associated with increased interferon titers. Interferon produced after exposure to RSV or to the influenza viruses was resistant to low pH treatment. The data suggest that interferon production may not be a major component of human immunological defense against RSV infection.     

Opposing effects of the interferon inducer, avridine: enhancement or suppression of tumor growth depending on treatment regimen

Tumor growth and regression was studied in C57BL/6J mice injected with Moloney sarcoma virus (MSV) and treated with the interferon (IFN)-inducing drug, avridine. Avridine decreased the persistence of tumors when given one or five days after virus, but shortened the prepatent period and increased persistence if given one day prior to virus. Additional studies were undertaken to study the role that serum interferon and natural killer (NK) cell activity might have in this phenomenon. Interferon levels were greatly enhanced (over that induced by virus alone or avridine alone) when avridine was given one day after, but not one day before, virus. Six days after viral infection, interferon titers had returned to near zero but could be boosted by injecting avridine at day 5. Multiple injections of avridine before and after virus resulted in refractoriness to interferon induction and tumor persistence. NK activity was greatly increased by virus at two days post-infection, and avridine given one day after infection significantly enhanced cytotoxicity of these splenic cells against tumor cells. By six days after infection, NK activity had returned to normal but could be increased by avridine given at five days post-infection. It appeared that high levels of interferon induced by avridine given at one or five days after infection increased NK activity and may have been responsible for enhanced regression. Pre-treatment by avridine had little effect on interferon levels over that induced by virus alone, but that did not explain the enhancement of tumor growth since NK activity was increased.(ABSTRACT TRUNCATED AT 250 WORDS)