Prophylactic activity of dihydroheptaprenol, a synthetic polyprenol derivative, against Sendai virus infection in mice

Synthesis and biological activity of polyprenols

The polyprenols and their derivatives are highlighted in this study. These lipid linear polymers of isoprenoid residues are widespread in nature from bacteria to human cells. This review primarily presents the synthesis and biological activities of polyprenyl derivatives. Attention is focused on the synthesis and biological activity of dolichols, polyprenyl ester derivatives and polyprenyl amines. Other polyprenyl derivatives, such as oxides of polyprenols, aromatic polyprenols, polyprenyl bromide and polyprenyl sulphates, are mentioned. It is noted that polyprenyl phosphates and polyprenyl-linked glycosylation have better antibacterial, gene therapy and immunomodulating performance, whereas polyprenyl amines have better for antibacterial and antithrombotic activity. Dolichols, polyprenyl acetic esters, polyprenyl phosphates and polyprenyl-linked glycosylation have pharmacological anti-tumour effects. Finally, the postulated prospect of polyprenols and their derivatives are discussed. Further in vivo studies on the above derivatives are needed. The compatibility of polyprenols and their derivatives with other drugs should be studied, and new preparations of polyprenyl derivatives, such as hydrogel glue and release-controlled drugs, are suggested for future research and development.

Multistrain influenza protection induced by a nanoparticulate mucosal immunotherapeutic

All commercial influenza vaccines elicit antibody responses that protect against seasonal infection, but this approach is limited by the need for annual vaccine reformulation that precludes efficient responses against epidemic and pandemic disease. In this study we describe a novel vaccination approach in which a nanoparticulate, liposome-based agent containing short, highly conserved influenza-derived peptides is delivered to the respiratory tract to elicit potent innate and selective T cell-based adaptive immune responses. Prepared without virus-specific peptides, mucosal immunostimulatory therapeutic (MIT) provided robust, but short-lived, protection against multiple, highly lethal strains of influenza in mice of diverse genetic backgrounds. MIT prepared with three highly conserved epitopes that elicited virus-specific memory T-cell responses but not neutralizing antibodies, termed MITpep, provided equivalent, but more durable, protection relative to MIT. Alveolar macrophages were more important than dendritic cells in determining the protective efficacy of MIT, which induced both canonical and non-canonical antiviral immune pathways. Through activation of airway mucosal innate and highly specific T-cell responses, MIT and MITpep represent novel approaches to antiviral protection that offer the possibility of universal protection against epidemic and pandemic influenza.

Viral pneumonia in children

Viral pneumonia causes a heavy burden on our society. In the United States, more than one million cases of pneumonias afflict children under the age of 5 years, costing hundreds of millions of dollars annually. The majority of these infections are caused by a handful of common viruses. Knowledge of the epidemiology of these viruses combined with new rapid diagnostic techniques will provide faster and more, reliable diagnoses in the future. Although the basic clinical epidemiology of these viruses has been carefully investigated over the last 30 years, new molecular techniques are greatly expanding our understanding of these agents and the diseases they cause. Antigenic and genetic variations are being discovered in many viruses previously thought to be homogeneous. The exact roles and the biological significance of these variations are just beginning to be explored, but already evidence of differences in pathogenicity and immunogenicity has been found in many of these substrains. All of this information clearly will impact the development of future vaccines and antiviral drugs. Effective drugs exist for prophylaxis against influenza A and respiratory syncytial virus, and specific therapy exists for influenza A. Ribarivin is approved for use in respiratory synctial virus infections, and it alone or in combination with other agents (eg, IGIV) may be effective in immunocompromised patients, either in preventing the development of pneumonia or in decreasing morbidity and mortality. Many new antiviral agents are being tested and developed, and several are in clinical trials.

A Prototype Prophylactic Anti-Influenza Preparation in Aerosol Form on the Basis ofAbies sibiricaPolyprenols

This research investigates a promising antiviral compound based on polyprenols from Siberian silver fir (Abies sibirica). The physico-chemical characteristics of a preparation developed in aerosol form and an estimation of its protective efficacy against aerosol challenge of laboratory animals are presented. It is shown that (1) by using a simple ultrasonic disperser one can obtain aerosol of three formulations studied with about 70% of its mass accumulated in the size range below 1.8 microm; (2) 40-100% of aerosol particles contain preparation for different formulations; (3) after delivering under specified schedules, the preparations as developed can protect up to 100% of mice against 5 LD(50) of influenza A/Aichi/2/68 (H3N2) virus aerosol infection. Animals inhaled twice the preparation doses (which were 100 times lower than injection ones of the same efficacy) and did not exceed 10 microg/mouse. It was shown that the mode of action of this immunomodulating preparation was nonspecific stimulation of immune cells' various activities.

Parainfluenza viruses

Human parainfluenza viruses (HPIV) were first discovered in the late 1950s. Over the last decade, considerable knowledge about their molecular structure and function has been accumulated. This has led to significant changes in both the nomenclature and taxonomic relationships of these viruses. HPIV is genetically and antigenically divided into types 1 to 4. Further major subtypes of HPIV-4 (A and B) and subgroups/genotypes of HPIV-1 and HPIV-3 have been described. HPIV-1 to HPIV-3 are major causes of lower respiratory infections in infants, young children, the immunocompromised, the chronically ill, and the elderly. Each subtype can cause somewhat unique clinical diseases in different hosts. HPIV are enveloped and of medium size (150 to 250 nm), and their RNA genome is in the negative sense. These viruses belong to the Paramyxoviridae family, one of the largest and most rapidly growing groups of viruses causing significant human and veterinary disease. HPIV are closely related to recently discovered megamyxoviruses (Hendra and Nipah viruses) and metapneumovirus.

Synthesis, biological evaluation, and pharmacophore generation of uracil, 4(3H)-pyrimidinone, and uridine derivatives as potent and selective inhibitors of parainfluenza 1 (Sendai) virus

Several new 6-oxiranyl-, 6-oxiranylmethyluracils, and pyrimidinone derivatives, synthesized by lithiation-alkylation sequence of 1,3,6-trimethyluracil, 1,3-dimethyl-6-chloromethyluracil, and 2-alkoxy-6-methyl-4(3H)-pyrimidinones, showed a potent and selective antiviral activity against Sendai virus (SV) replication. To gain insight into the structural features required for SV inhibition activity, the new compounds were submitted to a pharmacophore generation procedure using the program Catalyst. The resulting pharmacophore model showed high correlation and predictive power. It also rationalized the relationships between structural properties and biological data of these inhibitors of SV replication.

Effect of intramuscularly injected polyprenols on influenza virus infection in mice

This study demonstrates the possibility of achieving a prophylactic effect by intramuscular injection of Abies sibirica polyprenols for the control of influenza virus infection in mice. One of the five polyprenol preparations tested, preparation N1, which had the lowest hydrophilic-lipophilic balance (8.6), produced a significant protective effect when injected in a dose of 2000 microg/mouse 2 days before aerosol infection of mice with influenza virus. A moderate protective effect was also observed using a second preparation, designated N2. One day after aerosol infection, animals pre-treated with 2000 microg doses of the polyprenol preparations or Hanks' solution showed no difference in the level of interferon accumulation in the lungs. Three days after injection of preparation N2 and N1, a significant decrease in spleen and thymus weights was, observed in the mice. One day after injection of these preparations, the number of lymphocytes in the bronchoalveolar tract of the mice exceeded almost twice that seen in mice treated with placebo. After 3 days, relative and absolute numbers of macrophages decreased, whereas those of lymphocytes increased significantly. Three days after the administration of preparations N1 and N2, macrophages became approximately twice as active in absorbing zymozan granules. Preparation N1 affected the system of superoxide radical anion production to a greater extent than preparation N2. The production of radical anions by the macrophages of the bronchoalveolar tract in the mice, 1 day after intramuscular injection of preparation N1, was significantly higher than that seen on day 3 and that induced by preparation N2 1 and 3 days after injection. These data indicate that emulsions of polyprenols that have relatively low hydrophilic-lipophilic balance, inhibit influenza virus infection in mice through a modulation of the host immune response.

A potent and selective inhibition of parainfluenza 1 (Sendai) virus by new 6-oxiranyl-, 6-methyloxiranyluracils, and 4(3H)-pyrimidinone derivatives

Several new 6-oxiranyl-, 6-methyloxiranyluracils, and pyrimidinone derivatives, synthesized by the lithiation-alkylation sequence of 1,3,6-trimethyluracil, 1,3-dimethyl-6-chloromethyluracil, and 2-alkoxy-6-methyl-4(3H)-pyrimidinones, showed a potent and selective antiviral activity against the parainfluenza 1(Sendai) virus replication.

Synthetic immunoadjuvants: application to non-specific host stimulation and potentiation of vaccine immunogenicity

It is well recognized that immunoadjuvants mainly play two roles; non-specific stimulation of host resistance against infections and cancer, and the potentiation of vaccine immunogenicity. This article reviews the recent results of the development of synthetic immunoadjuvants in our laboratory with special reference to muramyldipeptide (MDP), trehalose dimycolate (TDM), lipid A, chitin and their related compounds. The usefulness of MDP derivative MDP-Lys(L18), which has recently gone on the market as a haematopoietic agent for restoration of leukopenia in cancer patients treated with radiotherapy and chemotherapy, is reviewed. The various approaches to application of synthetic immunoadjuvants to the potentiation of vaccine immunogenicity, including adjuvant formulation, are also discussed.