New Approaches to the Prevention and Treatment of Viral Diseases.

The review discusses a new approach to the prevention and treatment of viral infections based on the use of pine needles polyprenyl phosphate (PPP) and associated with the infringement of prenylation process-the attachment of farnesol or geranyl geraniol to the viral protein. Currently, prenylation has been detected in type 1 adenovirus, hepatitis C virus, several herpes viruses, influenza virus, HIV. However, this list is far from complete, given that prenylated proteins play an extremely important role in the activity of the virus. We assume that the interferon produced in response to PPP may suppress expression of the SREBP2 transcription factor. As a result, the mevalonic acid pathway is violated and, as a result, the formation of early polyprenols precursors (geraniol, geranyl geraniol, farnesol), which are necessary for the prenylation of viral proteins, is blocked and the formation of mature, virulent virus particles is broken. As a consequence, the maturation of viral particles is inhibited, and defective particles are formed. Polyprenol was extracted from greenery (pine, fir and spruce needles, mulberry leaves, etc.), purified by chromatography, phosphorylated and identified by HPLC and NMR. Obtained PPP was used as antiviral in some experimental models in vitro and in vivo. During numerous studies, it was found that PPP manifested versatile antiviral effects, both in vitro and in vivo. The maximum effect was observed with viruses in which the presence of prenylated proteins was established, namely influenza A virus, HIV-1, tick-borne encephalitis virus, hepatitis A and C viruses, herpes simplex viruses type 1 and 2, some coronavirus. The available data obtained both in the experimental conditions and during clinical trials allow us to regard PPPs as safe and effective medicine for prevention and treatment of viral diseases.

New polyprenyl phosphate based preparation Fortepren(®) as promising cytokine regulationg antiviral remedy.

Fortepren(®), a product of the phosphorylation of polyprenols from fir needles (with sodium polyprenyl phosphate being the main active ingredient), belongs to the class of antiviral drugs with immunomodulating activity. Fortepren(®) may be used as the drug of choice in the treatment of herpes diseases. It was shown that treatment with Fortepren(®) of patients with a chronic recurrent herpes infection after acute phase termination with acyclovir decreased the recurrence rate, as well as the severity of local symptoms. Fortepren(®) treatment of patients with a high incidence of recurrent herpes infection led to an increase in the interferon-producing ability of leucocytes stimulated with NDV, as well as in the production of key cytokines (IL-1ß, IL-15, MIP-1α, IFN-γ, IL-12 (p40), TNF-α, IFN-α2, IL-12 (p70), IL-6) taking part in the protection against viral infection. Data suggest that the action of the drug is directed, first of all, to the cells responsible for the natural resistance of the organism (macrophages, dendritic cells, etc.). The activation of natural immunity appears to be a leading mechanism of protection from herpesviral infection under the influence of polyprenyl phosphate.

Plant polyisoprenoids and control of cholesterol level.

The ability of plant polyisoprenoids (polyprenols and polyprenyl phosphates) to diminish the levels of serum cholesterol affecting its biosynthetic pathway are highlighted here. Possible mechanism of such process is discussed. It is also noted that polyisoprenoids can prevent toxic injuries of the liver and restore disturbed hepatic functions. The possibility of polyprenyl phosphates to reveal at the same time anti-inflammatory action suppressing lipoxygenase activity and lowering the levels of proinflammatory cytokines will be illustrated. Attention will be focused on the potential usefulness of plant polyisoprenoids in the course of prevention and treatment of hypercholesterolemia. High efficiency for combined use of polyprenyl phosphate and ß-sitosterol, which leads to substantial enhancement of the ability to overcome hypercholesterolemia versus the individual constituents will be demonstrated.

Polyprenols as possible factors that determine an instructive role of the innate immunity in the acquired immune response.

Polyprenols are an integral part of all living cells including prokaryotic and eukaryotic ones. These compounds take part in biosynthesis of glycoproteins. We have found that phosphates of polyprenols may act as effective antiviral agents with a wide spectrum of activity. One of such antiviral agents received from Pinus sativum polyprenols was named phosprenyl. Earlier we showed that phosprenyl expressed direct antiviral effect, while having mild immunomodulatory activity. In the present study we further evaluated influence of phosprenyl on the immune system. The drug was found to inhibit an early phase of IL-1 and Con A interaction in spleen cells as well as lypoxigenase activity and expression of IL-2 receptors. At the same time, phosprenyl induced NK cell activity and early TNF-alpha production. Basing on all these data we proposed that polyprenols could be considered as a "label" which grants a possibility to the innate immune system to recognize infection at the early stages and govern the acquired immunity.

Regulation of cytokine mRNAs by interferon and interferon inducers.

Cytokine mRNA expression was studied in human long-term cell cultures of different origin: J-96 and J-41 (monocytic leukemia), SW-13 (paradrenal adenocarcinoma), and MT-4 (T-cell leukemia), in response to IFN-alpha and IFN inducers (kagocel and cycloferon). Cytokine mRNA level in the cell cultures was measured by the RT-PCR method using 11 primer pairs for the following cytokines: IFN-alpha, IFN-gamma, IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-18 and TNF-alpha. It was shown that IFN-alpha and IFN inducers possess an ability to regulate different cytokine mRNAs. Treatment of the cells with IFN-alpha resulted in expression of mRNAs for IL-2, IL-4, and IL-8. Kagocel induced production of IFN-alpha, IFN-gamma, and IL-2 mRNAs, and cycloferon--IFN-gamma, IL-2, IL-4, and IL-8 mRNAs. It is suggested that antiviral effects of these inducers, in general, can be attributed to imitation of cytokine responses observed in viral infection and, as a result, can lead to starting-up of cellular defense antiviral mechanisms even before action of viruses. Conclusion is made that IFN and IFN inducers may act as regulators of cytokine activity.

Role of Cytokines in Immunomodulatory Effects of Polyprenyl Phosphate: New Generation of Antiviral Drugs.

Immunomodulatory properties of sodium polyprenyl phosphate (PP) were studied in vivo and in vitro. After injection to mice, PP was shown to increase serum levels of TNF-alpha, IL-6, and IFN-gamma. The simultaneous inoculation of tick-born encephalitis virus (TBEV) and PP to mice resulted in earlier serum appearance of IL-6, TNF-alpha and IFN-gamma (at days 1, 2 and 3, respectively) compared with mice which have received PP only. In TBEV-infected mice (not injected with PP) cytokines in serum were registered later - at day 7 after infection. Development of the disease with subsequent death was observed in 100% of infected mice. In contrast, mortality of mice infected with TBEV and simultaneously treated with PP was decreased to 40%. The study of spleen cell proliferative activity in mice injected with PP revealed a modulating effect of the latter. In vitro PP decreased spleen cell and Con A-induced blast proliferation stimulated by Con A and rIL-2 respectively. This effect was dependent upon PP inhibition of IL-2 binding to IL-2 receptors. It was concluded that PP induced early cytokine production (IL-6, TNF-alpha) by cells of monocyte/macrophage origin and, apparently, provided protection of mice against viral infection. Thus, the main properties of PP are the following: absence of the expressed direct effect on cytokine production and co-stimulating effect in combination with a bystander stimulus (in this case - TBEV).

Cell Interferon Sensitivity in Immunodeficiencies, Autoimmune and Allergic Diseases.

Novel approach is suggested to study interferon (IFN) system state in various immunopathological disorders. It is based upon measurement of IFN-alpha and/or IFN-gamma production by leukocytes primed with IFN-alpha or IFN-gamma respectively. Study of IFN-status parameters revealed a tendency to decrease in the induced IFN-alpha production in patients with secondary immune deficiency (SID), autoimmune syndrome (AIS), allergic diseases, lymphoadenopathy (LAP), chronic bronchitis (CB) and bronchial asthma (BAS). Production of the induced IFN-gamma was significantly depressed in all groups except LAP. In priming conditions production of IFN-alpha by leukocytes of the patients with SID, AIS, allergic diseases and LAP increased 1.27-fold (p < 0.02), 1.31-fold (p < 0.1), 1.31-fold (p < 0.001) and 1.27-fold (p < 0.05), respectively. Under the same conditions production of IFN-gamma by leukocytes of the patients with SID, AIS, allergic diseases, LAP and BAS increased 1.69-fold (p < 0.001), 2.42-fold (p < 0.01), 1.63-fold (p < 0.001), 1.4-fold (p < 0.1) and 1.69-fold (p < 0.05), respectively. The data obtained may be useful for understanding mechanisms of the IFN system deficiency development in immunopathological disorders, as well as for further development and improvement of IFN therapy.