A misaligned double-stranded RNA, poly(I).poly(C12,U), induces accumulation of 2',5'-oligoadenylates in mouse tissues

Vaccine adjuvant uses of poly-IC and derivatives

Pathogen-associated molecular patterns (PAMPs) are stand-alone immunomodulators or 'danger signals,' that are increasingly recognized as critical components of many modern vaccines. Polyinosinic-polycytidylic acid (poly-IC) is a synthetic dsRNA that can activate multiple elements of the host defense in a pattern that parallels that of a viral infection. When properly combined with an antigen, it can be utilized as a PAMP-adjuvant, resulting in modulation and optimization of the antigen-specific immune response. We briefly review the preclinical and clinical uses of poly-IC and two poly-IC derivatives, poly-IC12U (Ampligen) and poly-ICLC (Hiltonol), as vaccine adjuvants.

The 2-5A system: modulation of viral and cellular processes through acceleration of RNA degradation

The 2-5A system is an RNA degradation pathway that can be induced by the interferons (IFNs). Treatment of cells with IFN activates genes encoding several double-stranded RNA (dsRNA)-dependent synthetases. These enzymes generate 5'-triphosphorylated, 2',5'-phosphodiester-linked oligoadenylates (2-5A) from ATP. The effects of 2-5A in cells are transient since 2-5A is unstable in cells due to the activities of phosphodiesterase and phosphatase. 2-5A activates the endoribonuclease 2-5A-dependent RNase L, causing degradation of single-stranded RNA with moderate specificity. The human 2-5A-dependent RNase is an 83.5 kDa polypeptide that has little, if any, RNase activity, unless 2-5A is present. 2-5A binding to RNase L switches the enzyme from its off-state to its on-state. At least three 2',5'-linked oligoadenylates and a single 5'-phosphoryl group are required for maximal activation of the RNase. Even though the constitutive presence of 2-5A-dependent RNase is observed in nearly all mammalian cell types, cellular amounts of 2-5A-dependent mRNA and activity can increase after IFN treatment. One well-established role of the 2-5A system is as a host defense against some types of viruses. Since virus infection of cells results in the production and secretion of IFNs, and since dsRNA is both a frequent product of virus infection and an activator of 2-5A synthesis, the replication of encephalomyocarditis virus, which produces dsRNA during its life cycle, is greatly suppressed in IFN-treated cells as a direct result of RNA decay by the activated 2-5A-dependent RNase. This review covers the organic chemistry, enzymology, and molecular biology of 2-5A and its associated enzymes. Additional possible biological roles of the 2-5A system, such as in cell growth and differentiation, human immunodeficiency virus replication, heat shock, atherosclerotic plaque, pathogenesis of Type I diabetes, and apoptosis, are presented.

Activation of the murine monocyte/macrophage cell line, J774A1 by poly(A).poly(U): I. Binding of poly(A).poly(U) and induction of oligo-2',5'-adenylate synthetase

Binding and internalization of the synthetic double-stranded complex poly(A).poly(U) were studied on a murine monocyte/macrophage cell line J774A1. Poly(A).poly(U) increased in a dose-dependent fashion the oligo-2',5'-adenylate synthetase demonstrating that those cells were responsive to this agonist. Binding of [32P]poly(A).[32P]poly(U) to the cells reached an apparent kinetic equilibrium within 4 h and was saturable (apparent Kd = 9.99 +/- 0.09.10(-2) g/l and Bmax 13.3 +/- 5.3.10(-3) g/l per 10(6) cells) and temperature-dependent. The binding of poly(A).poly(U) was competitively inhibited by various polynucleotides but not by other structurally unrelated compounds. Analysis of cell-associated [32P]poly(A).[32P]poly(U) demonstrated a minimal degradation of this polyribonucleotide over a 4-h incubation period. Autoradiography of cells incubated with [3H]poly(A).[3H]poly(U) revealed that poly(A).poly(U) was internalized and migrated to cell nuclei. These results suggest that poly(A).poly(U) is internalized in J774A1 cells via an endocytotic process.

Anti-human immunodeficiency virus effects of zidovudine in combination with double-stranded RNA poly I poly C in T cells and monocytes-macrophages

A comparison of the activity against human immunodeficiency virus 1 of zidovudine (AZT) and poly I poly C double-stranded RNA both alone and in combination in MT4 cells and primary monocyte/macrophage (M/M) cultures was made. The inhibition of the HIV-induced cytopathic effect or reverse transcriptase production by AZT in MT4 cells was not modified by the combination of the two agents. In contrast, AZT inhibition of reverse transcriptase production in the supernatant of M/M cultures was enhanced by the addition of poly I poly C. The inhibitory effect of the drug combination was more marked in M/M than in MT4 cells, indicating that the evaluation of compounds involving the induction of an antiviral state should be tested not only CD4+ T cells but also in monocyte-macrophages.

In vitro evaluation of mismatched double-stranded RNA (ampligen) for combination therapy in the treatment of acquired immunodeficiency syndrome

Multiple drug effect analyses with mismatched double-stranded RNA (mismatched dsRNA or Ampligen) as a core drug were performed to identify other agents and mechanisms through which mismatched dsRNA may potentiate effective therapeutic intervention in human immunodeficiency virus (HIV) infection. Antiviral activities were defined by a microtiter infection assay utilizing MT-2 cells as targets and HTLV-III-B produced in H9 cells as a virus source. The scope of agents tested included rIFN-alpha A, rIFN-beta Ser 17, and rIFN-gamma as cytokines; azidothymidine and phosphonoformate (Foscarnet) as inhibitors of reverse transcription; ribavirin as a putative inhibitor of proper HIV mRNA capping; amphotericin B as a lipophile; and castanospermine as a glycoprotein processing (glucosidase I) inhibitor. Separately, each drug demonstrated dose-dependent anti-HIV activity and, when used in combination with mismatched dsRNA, demonstrated synergism. Although mismatched dsRNA was synergistic with all three IFNs for anti-HIV activity in microtiter infection assays, it did not potentiate the transient inhibition of virus production observed for IFN in cultures of H9/HTLV-III-B cells. The results of these studies suggest that the pleiotropic activities of dsRNAs differ from those of IFN and may provide synergism in combination therapy with a wide range of antiviral drugs for the treatment of the acquired immunodeficiency syndrome (AIDS).

Inhibition of HIV-1 proviral DNA synthesis and RNA accumulation by mismatched dsRNA

The antiviral activity of mismatched dsRNA of the form poly(I):poly(C12-U)n (Ampligen) against the human immunodeficiency virus type 1 (HIV-1) was investigated by RNA-RNA and RNA-DNA hybridizations. Mismatched dsRNA delayed the appearance of newly transcribed HIV-1 RNA as detected by liquid dot-blot hybridization in cultures of H9 T-lymphoblastoid cells following virus challenge. The appearance of proviral DNA as detected by Southern hybridization following virus challenge in H9 cells was also delayed. Mismatched dsRNA had no effect in syncytium inhibition assays performed by fusing MT-2 cells with H9/HTLV-IIIB cells. These results suggest that the in vitro anti-HIV-1 activity of mismatched dsRNA occurs, at least in part, at an early stage in the viral replication cycle following initial gp120-CD4 binding.

Mismatched dsRNA (ampligen) induces protection against genomic variants of the human immunodeficiency virus type 1 (HIV-1) in a multiplicity of target cells

Mismatched double-stranded RNA of the form r(I)n.r(C12-U)n (Ampligen) has been shown to be active against human immunodeficiency virus type 1 (HIV-1) using CEM and C3 cells as targets for infection by the highly similar HIV-1 isolates HTLV-IIIB and LAV (Montefiori, D.C. and Mitchell, W.M., 1987, Proc. Natl. Acad. Sci. U.S.A., 84, 2985-2989). The scope of Ampligen's anti-HIV-1 activity was examined in this study using the genetically divergent HIV-1 isolate HTLV-IIIRF, two additional target T-cell lines, H9 and MT-2, and a monocyte/macrophage cell line, U937. As judged by indirect immunofluorescence, reverse transcriptase activity and vital dye uptake, Ampligen was active against HTLV-IIIRF in H9, MT-2, C3 and U937 cells in addition to being active against HTLV-IIIB in U937 cells. A minimum of 1 h preincubation of cells (MT-2) with Ampligen was required for maximum activity. These results suggest that Ampligen's potential clinical efficacy may not be limited by either the highly variable nature or host cell range of HIV-1.

Do viruses play an etiologic role in ankylosing spondylitis or psoriatic arthritis?

High venous blood levels of 2-5A, an adenylic acid polymer synthesized in the presence of double-stranded RNA and considered as a viral replication indicator, have been found in blood samples from ankylosing spondylitis and psoriatic arthritis patients, but not from patients with seropositive rheumatoid arthritis or acute chondrocalcinosis. These findings suggest the possibility that ankylosing spondylitis and psoriatic arthritis might be virus-induced diseases.

Clinical, immunological, and virological effects of ampligen, a mismatched double-stranded RNA, in patients with AIDS or AIDS-related complex

10 patients with the acquired immunodeficiency syndrome (AIDS), AIDS-related complex (ARC), or lymphadenopathy syndrome (LAS) were given 200-250 mg ampligen, a mismatched double-stranded (ds) RNA with in-vitro antiviral activity against human immunodeficiency virus (HIV), twice a week for up to 18 weeks, without side-effects or toxicity. In all 9 patients who were positive for HIV RNA in peripheral blood mononuclear cells before therapy, levels became undetectable between days 10 and 40 of the start of therapy. 6 of the 7 patients with ARC or LAS also showed a progressive reduction in HIV load as measured by co-culture assays. All 10 patients had augmentation of delayed-type hypersensitivity skin reactions. Other changes noted during ampligen therapy included an increase in or maintenance of numbers of helper-inducer T lymphocytes, improvements in HIV-related symptoms, rises in titre of neutralising antibodies against HIV, and restoration of proper functioning of the natural lymphocyte antiviral dsRNA-dependent (2'-5'-oligoadenylate/RNA-ase L) pathway. Thus, in the short term, ampligen seems to have the dual ability to restore immunological function and to control HIV replication.

Antiviral activity of mismatched double-stranded RNA against human immunodeficiency virus in vitro

The biological response modifier r(I)n.r(C12-U)n, referred to here as mismatched double-stranded (ds) RNA, was examined for antihuman immunodeficiency virus (HIV) activity in vitro because of its known antiviral activity and ability to induce interferon (IFN) in other biological systems [Carter, W. A., Strayer, D. R., Hubbell, H. R. & Brodsky, I. (1985) J. Biol. Response Modif. 4, 495-502]. We found that cultures of the highly HIV-permissive T-cell line C3 were afforded significant protection from HIV infection when incubated in growth media supplemented with mismatched dsRNA at 10-50 micrograms/ml prior to virus challenge. Similar results were obtained at 50 micrograms of mismatched dsRNA per ml in cultures of the T-lymphoblastoid cell line CEM. Infections were monitored by indirect immunofluorescence of cells for viral p24 antigen expression, reverse transcriptase activity in culture fluids for virus production, and vital dye uptake for cytopathic effect. Antiviral activity was increased by the continued presence of mismatched dsRNA in cultures following virus challenge. A one-time exposure to mismatched dsRNA (50 micrograms/ml) provided greater antiviral activity than either a one-time exposure to recombinant IFN-alpha [250 international units (IU)/ml], IFN-beta (250 IU/ml), or IFN-gamma (50 IU/ml) in cultures of CEM cells, or a one-time exposure to a combination of all three IFNs (150 IU each per ml) in cultures of C3 cells. Mismatched dsRNA at 50 micrograms/ml had no effect on cell division, RNA and protein synthesis, or virus replication in all T-cell lines examined. A clear distinction between the activities of mismatched dsRNA and IFN was the ability of IFN to suppress the in vitro replication of HIV that occurred at IFN concentrations (150 IU each of alpha, beta, and gamma per ml) that provided less antiviral activity than mismatched dsRNA (50 micrograms/ml). The results of these in vitro studies suggest a potential therapeutic value for mismatched dsRNA in the treatment of acquired immunodeficiency syndrome (AIDS).

Mismatched double-stranded RNA (ampligen) reduces concentration of zidovudine (azidothymidine) required for in-vitro inhibition of human immunodeficiency virus

'Ampligen', a non-toxic, mismatched polymer of double-stranded RNA with antiviral and immunomodulatory activities reduced the concentration of zidovudine (azidothymidine, AZT; 'Retrovir', Wellcome) required for inhibitory activity against human immunodeficiency virus (HIV) in vitro. At the higher doses of AZT tested, the virustatic activity observed seemed to have a synergistic virustatic relation with ampligen. Thus, combined therapy with ampligen and AZT can be expected to be more beneficial than AZT alone to patients with the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex since AZT regimens that seem to be clinically effective are associated with considerable toxicity.