Search

Human natural interferon-beta (HuIFN-beta) was administered through different routes (intravenous [i.v.], intramuscular [i.m.], and subcutaneous [s.c.]) and its distribution in lymph and plasma was evaluated. After i.v. (bolus) administration the lymph/plasma ratio was about 0.35 but it significantly increased (11-fold) after i.m. administration. Addition of human albumin (ALB) to the IFN solution did not favor IFN absorption through the lymphatics. On the other hand, addition of ALB improved IFN absorption through the lymphatics after s.c. administration. These results are interesting because they clarify why IFN-beta can exert immunomodulatory activities in spite of very low plasma levels.

Several investigators have shown that the production of interferon (IFN-β) by human or rabbit fibroblasts stimulated with polyrI.polyrC is enhanced by inhibitors of macromolecular synthesis (1-5). Maximal enhancement is achieved if inhibitors are used sequentially to block the synthesis of a regulatory substance. This involves the treatment of cells with a reversible inhibitor of protein synthesis during the transcription of IFN-mRNA. Prior to the reversal of inhibition of protein synthesis, actinomycin D treatment is initiated to inhibit further transcription of the regulatory substance. In this paper we show that the induction of IFN-β results in newly transcribed mRNA for IFN-β. The newly transcribed IFN-β-mRNA appears in the cytoplasm as the polyadenylated form and is converted to the nonpolyadenylated form by the fourth hour. When cells are treated by different procedures to enhance IFN production, the level of polyadenylated IFN-β-mRNA is not only increased but is maintained longer for at least another 7 hours.

Exogenously administered interferons are rapidly cleared from the body. Several pharmacological mechanisms have been implicated in this clearance; however, they do not entirely explain the different clearance rates of the interferons. Cultured cells were studied for their ability to regulate interferon levels in vitro. Preparations of MuIFN-alpha, MuIFN-beta, and MuIFN-gamma were exposed to cells in culture and monitored for any loss in titer. MuIFN-beta titers were found to be significantly reduced following exposure to mouse L-929 fibroblast cells. The reduction of MuIFN-beta activity appeared to be specific for fibroblasts, since the reduction occurred following exposure to L-cells and to mouse embryo fibroblasts, but not to mouse reticuloendothelial cells. Moreover, the ability of the mouse fibroblast cells to reduce MuIFN-beta titers was blocked if the cells were pre-treated with actinomycin D, suggesting that de novo RNA synthesis was required. The titers of IFN-alpha and IFN-gamma were not reduced following exposure to either fibroblast or reticuloendothelial cells. Thus, the reduction of interferon titer by fibroblasts was IFN-beta specific. Similarly, HuIFN-beta titers were reduced following exposure to human fibroblasts. The ability of fibroblast cells to reduce IFN-beta titers was also found to be species-specific, since human fibroblast cells reduced the titer of HuIFN-beta but not MuIFN-beta while murine fibroblasts reduced the titer of MuIFN-beta but not HuIFN-beta. These results suggest that IFN-beta-treated fibroblasts specifically regulate their response to IFN-beta by reducing the titer of the IFN-beta activity.

Earlier studies showed that both tumor necrosis factor (TNF) and interleukin-1 (IL1) can inhibit virus replication in cultured cells. However, in human FS-4 fibroblasts, in which recombinant human TNF protected cells from encephalomyocarditis (EMC) virus infection, recombinant human IL1 alpha and IL1 beta failed to induce antiviral protection. Moreover, both forms of IL1 inhibited the development of the TNF-induced antiviral state. To elucidate the mechanism of this inhibition, we examined the effect of IL1 on the synthesis of interferon-beta (IFN-beta), stimulated with polyinosinate.polycytidylate [poly(I).poly(C)]. When added 2 h or more before poly(I).poly(C), both forms of IL1 had a strong inhibitory effect on IFN-beta synthesis, as determined by antiviral assay of the IFN-beta protein or by quantitation of IFN-beta mRNA levels in Northern blot analysis. However, when IL1 was added simultaneously with poly(I).poly(C), or 2 h after poly(I).poly(C), IFN-beta synthesis was increased. The inhibitory action of IL1 on poly(I).poly(C)-induced IFN-beta synthesis was abolished in the presence of cycloheximide, suggesting that it is mediated indirectly by an IL1-induced product in the FS-4 cells. In addition to its ability to inhibit IFN-beta synthesis, IL1 also caused a partial reversal of the antiviral action of IFN-beta. In contrast to IL1, TNF did not inhibit IFN-beta synthesis, nor did it interfere with the antiviral action of IFN-beta. Simultaneous addition of TNF and poly(I).poly(C) to FS-4 cells enhanced IFN-beta synthesis. Under proper conditions TNF and IFN-beta showed an additive antiviral effect.

Interferon β produced by a cell line (MRC-5) of human embryonic lung fibroblasts adsorbs to Blue Sepharose CL-6B and may be dissociated at neutral pH using a buffer containing poly(vinylpyrrolidone) and sodium chloride. Poly(vinylpyrrolidone) of M r 2500 or of M r 25 000 is equally efficient on a w/w basis. The effect of substituting volatile ammonium salts for the sodium chloride has been investivated. The benefits of the use of poly(vinylpyrrolidone) compared with the use of the commonly-used dissociating agent, 1,2-ethanediol, are discussed. It is concluded that interferon preparations eluted by poly(vinylpyrrolidone) from Blue Sepharose may be suitable for clinical use with minimal additional processing or formulation.

Antitumor activity and toxicity of β-interferon (β-IFN) were studied in phase 2 clinical trials. β-IFN was administered to four malignant brain tumor patient (14-54 years old: male 3, female 1), 3 with glioblastoma and 1 with astrocytoma. As to the route of administration, β-IFN was generally given intravenously, but in case of intravenous administration, serum IFN titer was decreased immediately. Based on this observation, we injected IFN directly into the brain tumor by way of Ommaya's reservoir. In principle, IFN was administered daily and the dose of IFN was started from 30 × 10 4 unit/day. The period of β-IFN administration to each patient was 7 to 30 weeks. And the total dose of administered IFN was 94 × 10 6 units to 10 units.

Cytokines are humoral factors which play an important role in immunity. They are produced in extremely small quantities, but can be detected in vitro due to their very high specific activity in various biological tests, such as growth assays, in which they are active at the ng level. By the use of advanced purification methods and recombinant techniques, research on identification and production of a number of cytokines has made a tremendous progress. Thus, it has become clear that several biologically defined factors correspond to the same molecular structure.

The in vitro effects of recombinant human interferon-beta ser (rIFN-beta ser) and 3'-azido-3'-deoxythymidine (AZT) alone and in combination on human immunodeficiency virus (HIV) replication were examined. rIFN-beta ser inhibited HIV progeny virus synthesis in cell cultures chronically infected with HIV. When used in combination, suboptimally effective concentrations of rIFN-beta ser and AZT synergistically inhibited HIV-mediated syncytium formation in HeLa T4 cell cultures. Whereas AZT alone reduced HIV replication in human MT-2 cells, addition of low concentrations of rIFN-beta ser reduced by 4- to 1,000-fold the amount of AZT required to maximally block HIV p24 antigen synthesis and HIV-mediated cell lysis. No drug-related cytoxicity was observed when the two agents were used together at and above maximally effective concentrations. These results suggest that a safer, yet effective, therapy for HIV infections may be achieved with reduced doses of AZT in combination with rIFN-beta ser.

F-IFr cells, which are more resistant to the anticellular and antiviral action of human alpha and beta interferons (IFN-alpha and IFN-beta) than the parental RSa cells, were also found to be more resistant to both the anticellular and antiviral effect of IFN-gamma. A high level of 2-5A synthetase was induced by treatment with IFN-alpha or -beta, but induction of 2-5A synthetase was not detected after IFN-gamma treatment of the cells. F-IFr cells had less than half the number of specific binding sites for IFN-alpha than the parental RSa cells.

In this phase I study 15 patients with metastatic tumors were given interferon (IFN)-beta by i.v. bolus injections. Twelve individual doses of 1, 2, 3.3, 5, 7, 9, 12, 16, 21, 27, 35, and 46 x 10(6) IU were administered every other day. The single maximal tolerated dose ranged from 9 to 46 x 10(6) IU. Eight patients tolerated the dose of 46 x 10(6) IU without side effects. Disturbances of cardiac rhythm were observed, but were closely related temporally to severe chills and appeared to be the consequence of adrenergic stimulation associated with this side-effect. In addition, no significant variations in the left ventricular function as assessed by nuclear stethoscope were observed. Neurotoxicity was not a major side-effect. The toxicity of IFN-beta given as scheduled in this study was significant, but acceptable.

Our previous studies have demonstrated that expression of epidermal fatty acid binding protein (E-FABP) in tumor associated macrophages (TAMs) promotes macrophage anti-tumor activity by enhancing IFNβ responses in tumor models. Thus, E-FABP represents a new protective factor in enhancing tumor immune surveillance against tumor development. Herein, we report the compound 5-(benzylamino)-2-(3-methylphenyl)-1,3-oxazole-4-carbonitrile (designated EI-05) as a novel E-FABP activator for inhibition of mammary tumor growth. EI-05 was selected from the ZINC compound library using molecular docking analysis based on the crystal structure of E-FABP. Although EI-05 is unable to bind E-FABP directly, it significantly increases E-FABP expression in macrophages during inflammation. Stimulation of macrophages with EI-05 remarkably enhances lipid droplet formation and IFNβ production, which further promotes the anti-tumor activity of macrophages. Importantly, administering EI-05 in vivo significantly inhibits mammary tumor growth in a syngeneic mouse model. Altogether, these results suggest that EI-05 may represent a promising drug candidate for anti-tumor treatment through enhancing E-FABP activity and IFNβ responses in macrophages.

Background: Neutralizing anti-drug antibodies (NAbs) to interferon beta (IFNβ) develop in up to 47% of multiple sclerosis (MS) treated patients inhibiting treatment effect of IFNβ. However, the long-term effect of NAbs remain unknown. Objective: To investigate the long-term consequences of high titre NAbs to IFNβ on disease activity and progression in MS patients. Methods: An observational study including data from all IFNβ treated relapsing remitting MS patients with sufficient NAb test results from the Swedish MS registry. Patients were classified into either confirmed ‘high titre’ or ‘persistent negative’ groups and analysed for differences in disease activity and progression over time. Results: A total of 197 high-titre and 2907 persistent negative patients with 19969.6 follow up years of data were included. High titre NAbs were associated with a higher degree of disease activity at baseline. However, even when accounting for this, the presence of high titre NAbs were also associated with higher disease activity during IFNβ treatment. This persisted even after the next DMT start, suggesting that earlier high titres may partially reduce the effect of later treatments. No difference was found in confirmed disability progression. Conclusion: High titre NAbs to IFNβ are associated with higher disease activity, persisting even after IFNβ discontinuation or switch. These results support use of highly efficient treatment earlier in patients with active disease, to avoid these complications.