Inhibitory Effects of Acyclic Nucleoside Phosphonate Analogues on Hepatitis B Virus DNA Synthesis in HB611 Cells

By using an assay system based on a human hepatoblastoma cell line (HB611) that continuously synthesizes hepatitis B virus (HBV) DNA, 56 acyclic nucleoside phosphonate analogues were examined for their inhibitory effects on HBV DNA synthesis. The following compounds were found to inhibit HBV DNA synthesis at concentrations that were significantly lower than their minimum cytotoxic concentrations; 9-(2-phosphonylmethoxyethyl)adenine (PMEA), 9-(2-phosphonylmethoxyethyl) guanine(PMEG), 9-(2-phosphonylmethoxyethyl) guanine ethyl ester (PMEGEE), 9 - (2 - phosphonylmethoxyethyl) - 1 - deazaadenine (PMEC1A), 9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (PMEDAP), ( S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA), 9-(3-isopropoxy-2-phosphonylmethoxypropyl)adenine (IPPMPA), 9-( RS)-(2-phosphonylmethoxypropyl)adenine (PMPA) and 9-(3-hydroxy-2-phosphonylmethoxypropyl)-2, 6-diaminopurine (HPMPDAP). The most selective compounds (with indexes greater than 100) were PMEDAP, PMEA, IPPMPA, and PMPA. Acyclic pyrimidine nucleoside phosphonate analogues did not prove markedly selective as anti-HBV agents. Diphosphoryl derivatives of some acyclic purine nucleoside phos-phonates (i.e. PMEA, PMEDAP, HPMPA) were prepared. They proved inhibitory to HBV DNA polymerase but not cellular DNA polymerase α.

Selective Activity of Various Nucleoside and Nucleotide Analogues against Human Herpesvirus 6 and 7

We have developed a new sensitive enzyme immunoassay (EIA) and MTT (tetrazolium salt) assay for screening compounds against two variants of human herpesvirus 6 (HHV-6A, HHV-6B) and human herpesvirus 7 (HHV-7) and evaluated the anti-HHV-6 and HHV-7 activity of a series of anti-herpesvirus compounds and acyclic nucleoside phosphonate analogues. The results indicate that the pattern of activity of these compounds against these betaherpesviruses is similar to that for human cytomegalovirus (HCMV). The highest potency and selectivity against the two variants of HHV-6 and HHV-7 was demonstrated by S2242 (N7-isomer of 6-deoxy-ganciclovir). Also, ganciclovir (GCV), foscarnet, (phosphonoformic acid; PFA) and the acyclic nucleoside phosphonate analogues such as cidofovir (HPMPC) exhibited selective inhibitory activity against these viruses. Thymidine kinase (TK)-dependent drugs (acyclovir, ACV; brivudin, BVDU; and sorivudine, BVaraU) showed little, if any, activity. These results suggest a structural homology of the DNA polymerase and a lack of TK gene among these three betaherpesviruses (HHV-6, HHV-7 and HCMV). The finding that HHV-7 was highly sensitive to GCV also suggests that HHV-7 may have an HCMV-UL97-homologue gene for the phosphorylation of GCV. The present EIA method is more rapid and sensitive than the previously reported procedures and could be useful for the large-scale screening of compounds against HHV-6 and HHV-7.

In-vitro anti Myxovirus Activity and Mechanism of Antiinfluenzavirus Activity of Polyoxometalates PM-504 and PM-523

Sixty polyoxometalates were examined for anti-influenza A virus (FluV-A) activity in vitro. Two of the most potent and least cytotoxic compounds, PM-504 K9H5(Ge2Ti6W18O77)16H2O] and PM-523 (iPrNH3)6H [PTi2W10O38(O2)9H2O2] were selected for further studies. Examination of the antiviral effects of PM-504 and PM-523 against other human ortho- and paramyxoviruses revealed that both compounds had broad spectrum antimyxovirus activities. From a time of addition study and FACS analysis for influenza A virus infected cells, the compounds were found not to inhibit binding of virus to MDCK cells. However, these compounds inhibited haemolysis of chicken erythrocytes by virus and also inhibited fluorescence dequenching of octadecylrhodamine B-labelled virus after binding to cells. This indicates that these polyoxometalates inhibited fusion of the virus envelope to the cellular membrane.

Inhibition of Thymidylate Synthetase Activity Induced in Varicella-Zoster Virus Infected Cells by (E)-5-(2-bromovinyl)-2′-deoxyuridine

The authors investigated the effect' of thymidylate synthetase (TS) on the antivariclllazoster virus (VZV) activity of ( E)5-(2-bromovinyl)-2′-deoxyuridine (BVDU). TS catalyses the conversion of deoxyuridylate (dUMP) to thymidylate (dTMP) and is a key enzyme in pyrimidine biosynthesis, providing the only source of dTMP synthesized de novo in mammalian cells. VZV encodes a specialized viral form of TS. TS activity in cells infected with VZV (TIO-VZV and TK−-VZV) increased proportionally with focus formation. From kinetic analysis using the Michaelis-Menten equation, the authors determined a Km value of 6.6μm for dUMP of TS induced in VZV-infected cells and a corresponding value from mock-infected cells of only 2.8μm. BVDU inhibited the induction of TS activity in TK+-VZV-infected cells at concentrations under ×10−3μm, but did not inhibit TS activity of TK−-VZV- or mock-infected cells at concentrations as high as 10μm. Inhibitory activity of BVDU against TS induced in TK+-VZV-infected cells appears to occur when BVDU is phosphorylated to BVDU monophosphate by viral pyrimidine kinase. These results suggest that the selective inhibitory action of BVDU on VZV replication depends on a specific interaction with both viral TK and TS. 5-Bromodeoxyuridine and 5-iododeoxyuridine inhibited TS activities induced in both VZV (TK+, TK−) and mock-infected cells. Other antiherpes compounds [i.e. 1-β-D-arabinofuranosyl- E-5-(2-bromovinyl)uracil, 9- 2-hydroxyethoxymethyl)-guanine, arabinosyladenine, and others] did not inhibit TS activity in VZV-infected cells at concentrations Of 10μm.

Antiviral Activity of a Sulphated Polysaccharide Extracted from the Marine Pseudomonas and Marine Plant Dinoflagellata against Human Immunodeficiency Viruses and other Enveloped Viruses

A natural sulphated mucopolysaccharide (OKU40), extracted from a marine plant Dinoflagellata, and an artificial sulphated polysaccharide (OKU41), prepared from a marine Pseudomonas, displayed antiviral activities against several enveloped viruses. OKU40 and OKU41 were found to be homogenous in electrophoresis and sedimation velocity and had a molecular weight of 8.0 × 1065.0 × 105respectively. The sulphation rate of OKU40 and OKU41 was 8.9% and 5.4%, respectively. Each OKU40 and OKU41 inhibited the cytopathic effect of human immunodeficiency virus type 1 (HIV-1), type 2 (HIV-2) and zidovudineresistant HIV-1 in MT-4 cells at similar concentrations to those of dextran sulphate (molecular weight: 5000) (50% inhibitory concentrations: 0.86-1.95 μg mL−1), whereas these compounds did not affect the growth and viability of mock-infected MT-4 cells at concentrations up to 500 μg mL−1. These compounds proved inhibitory not only to HIV-1 and HIV-2 but also to other enveloped viruses, i.e. herpes simplex virus type 1, influenza virus A and B, respiratory syncytial virus and measles virus. OKU40 and OKU41 suppressed syncytium formation induced by cocultivation of MOLT-4/IIIb and MOLT-4 cells at concentrations higher than 20 μg mL−1. Although OKU41 inhibited the binding of HIV-1 to the host cells and the binding of anti-gp120 monoclonal antibody to HIV-1 gp120, OKU40 did not inhibit these bindings, suggesting that the mechanism of anti-HIV activity of OKU40 and OKU41 may be primarily due to the inhibition of virus-cell fusion and viral adsorption to the host cells, respectively. Furthermore, these compounds did not inhibit to the blood coagulation process at a concentration that was significantly inhibitory to HIV replication. The compounds appear to have an interesting potential as virucidal agents.

Inhibitory Effect of Pyridobenzoazoles on Orthomyxo-and Paramyxovirus Replication in vitro

Among thirteen newly synthesized pyridobenzoazole derivatives which have been examined for anti-myxovirus and antiherpesvirus activities, three benzimidazoles emerged as potent anti-orthomyxo- or paramyxovirus compounds. 4-Cyano-2-benzamide-1-oxo-1,5-dihydropyrido[1,2a]benzimidazole (CBO-PB) showed broad antiviral activities against paramyxo-and orthomyxoviruses with EC50 of 0.1–2.0 μg ml−1, and 2-cyano-1-amino derivatives of CBO-PB (CCI-PB) were inhibitory to paramyxoviruses at 1.4–8.5 (μg ml−1 by a plaque reduction method. The third compound, 2-ethoxycarbonyl derivatives of CCI-PB was inhibitory only to respiratory syncytial virus (RSV) at 15–28 μg ml−1. Selectivity indexes of these 3 compounds for RSV in HeLa cells were 60, 86, and >13, respectively. All three compounds inhibited syncytium formation of RSV and Parainfluenzavirus (PFLUV) type 3 at comparable concentrations with EC50 for plaque formation. They inhibited antigen production of RSV and PFLUV at the concentrations that were 4 to 20-fold higher than those needed for plaque reduction, but they did not inhibit adsorption of virus to cells at all. All three compounds inhibited the growth of RSV in HeLa cells at 4-fold higher concentrations than their EC50 for plaque reduction.

Potent and Selective Activity of Dextrin Sulphate against Human Immunodeficiency Virus Type 1 in vitro

Several dextrin sulphate derivatives were prepared and investigated for their activity against human immunodeficiency virus type 1 (HIV-1) in vitro. These compounds have proved to be potent and selective inhibitors of HIV-1. One of the compounds, termed FG-752 [molecular weight (MW) 3000], was the most active, and its 50% antiviral effective concentration was 2.1 μg ml−1 (0.7 μm) in MT-4 cells. No toxicity for the cells was observed at a concentration of 500 μg ml−1. The compounds were also inhibitory to HIV-1-induced giant cell (syncytium) formation. These results suggest that dextrin sulphate may be useful for the chemotherapy of HIV-1 infections.

In vitro Antimyxovirus and Anti-Human Immunodeficiency Virus Activities of Polyoxometalates

Polyoxometalates have been shown to inhibit the replication of retro-, toga-, paramyxo- and herpesviruses. The primary mechanism of the anti-human immunodeficiency virus type 1 (HIV-1) action of polyoxometalates seems to be inhibition of binding of virus to cells and inhibition of syncytium formation. Since myxoviruses and HIV-1 are known to interact with the cytoplasmic membrane by adsorption and penetration of virus and by fusion of infected and uninfected cells, 25 polyoxometalates were examined for anti-ortho-, anti-paramyxovirus and anti-HIV-1 activity in vitro. Of the 25 compounds evaluated, 24 showed antiviral effects against influenza virus A, 11 showed activity against respiratory syncytial virus, six showed activity against measles virus, and 23 were considered effective against HIV-1 at a lower concentration than that producing cytotoxicity. Four polyoxotungstates which had potent inhibitory effects were examined for inhibitory effects against additional ortho- and paramyxoviruses, and proved to have a broad spectrum of antimyxoviral activity. HS-058, the Keggin sandwich compound K10Fe4(H2O)2(PW9O34)2·nH2O, was inhibitory against influenza viruses A and B, respiratory syncytial virus, measles virus, and parainfluenza virus 2, with median effective concentrations of 1.4, 21.8, 7.4, 0.8 and 0.32 μ,M, respectively. However, HS-058 had no effect on parainfluenza virus 3 or mumps virus. The median cytotoxic concentration of HS-058 for Madin-Darby canine kidney (MDCK) and HEp-2 cells was more than 200 μM and that for HMV-2 and Vero cells was about 50 μM. When HS-058 was added at different times after influenza A and respiratory syncytial virus infection, it inhibited binding of the latter but not of the former to cells. However, at higher concentrations, HS-054 and HS-058 inhibited haemolysis of chick erythrocytes by influenza virus and syncytium formation involving respiratory syncytial virus-infected cells and uninfected cells. Four times the median effective antiviral concentration of HS-058 completely inhibited the growth of influenza virus A in MDCK cells when compound was added before virus adsorption. Furthermore, when HS-058 was added after virus adsorption, it inhibited the yield of virus in MDCK cells infected at low but not at high multiplicity of infection.

Antiviral Activities of Mizoribine and other Inosine Monophosphate Dehydrogenase Inhibitors against Several Ortho- and Paramyxoviruses

Mizoribine (4-carbamoyl-1-β-D-ribofuranosylimidazo-lelium-5-olate), EICAR (5-ethynyl-1-β-D-ribofuranosylimi-dazole-4-carboxamide), mycophenolic acid and ribavirin are antiviral agents targeted for inosine monophosphate (IMP) dehydrogenase. These compounds have been examined for their activities against orthomyxoviruses [influenza viruses (FluV)] and paramyxoviruses [parainfluenza viruses (PFIuV), mumps virus, measles virus (MLSV) and respiratory syncytial virus (RSV)] in vitro. Mizoribine was 1- to 9-fold more active than ribavirin against RSV, PFIuV and MLSV. EICAR and mycophenolic acid showed higher potency than mizoribine and ribavirin against all myxoviruses examined. None of the four compounds examined proved cytotoxic to stationary host cells (HeLa, Vero and MDCK) at a concentration of 200 μg ml−1 or more. On the other hand, EICAR and mycophenolic acid were toxic to rapidly growing cells at concentrations of 2.2-9 and 0.1-1.1 μg ml−1, respectively. Mizoribine and ribavirin showed cytotoxicity to the growing cells at higher concentrations (12-51 μg ml−1). The antiviral activities of mizoribine against FluV and RSV were reversed by 25-100 μm of each of guanosine and guanosine monophosphate (GMP). The antiviral activity of ribavirin against FluV was reversed by 25 μg of each of guanosine and GMP, while its activity against RSV was reversed by ≥ 100 μm of each of these compounds. Neither xanthosine nor xanthosine monophosphate (XMP) reversed the antiviral effects of mizoribine and ribavirin at concentrations of 300 μM. Concentrations 9 times higher than the median effective doses (EC50) of mizoribine and ribavirin inhibited the growth of RSV in HeLa cells as determined in an assay of infectious virus yield. Mizoribin should be further pursued as a candidate drug for the treatment of ortho- and paramyxovirus infections.

Inhibition of HIV-1-Induced Cytopathogenicity, Syncytium Formation, and Virus-Cell Binding by Naphthalenedisulphonic Acids through Interaction with the Viral Envelope gp120 Glycoprotein

Bis-naphthalenedisulphonic acid derivatives with a biphenyl spacer, 4,4′-[4,4′-biphenyldiylbis(sulphonyl-amino)]bis(5-hydroxy-2,7-naphthalenedisulphonic acid) and 3,3′-[4,4′-biphenyldiylbis(sulphonyl-amino)]bis(1,5-naphthalenedisulphonic acid), have previously been reported as potent and selective inhibitors of human immunodeficiency virus type 1 (HIV-1) replication in cell culture. These compounds have also proved inhibitory to syncytium formation in cocultures of MOLT-4 cells with HIV-1-infected HUT-78 cells. They also inhibit the binding of HIV-1 virions to MT-4 cells as determined by a flow cytometric (FACS) method. Further studies on their mechanism of action by the FACS have revealed that the compounds inhibit the binding of anti-gp120 monoclonal antibody to the viral envelope glycoprotein gp120. Binding of OKT4A/Leu3a monoclonal antibody to the cellular CD4 receptor is not affected by the compounds. These results suggest that the anti-HIV-1 activity of the naphthalenedisulphonic acid derivatives can be attributed to inhibition of the gp120-CD4 interaction through binding of the compounds to the viral gp120 antigen.

Ingenol Derivatives are Highly Potent and Selective Inhibitors of HIV Replication in Vitro

Ingenol 3,5,20-triacetate has recently been identified as a highly potent and selective inhibitor of HIV replication in vitro. To evaluate the potential of ingenol derivatives as anti-HIV agents, several ingenol derivatives have been synthesized and investigated for their anti-HIV activities, structure-activity relationships, and possible mechanisms of action. Among the ingenol derivatives, 13-hydroxyingenol-3-(2,3-dimethylbutanoate)-13-dodecanoate (RD4-2138) proved to be a highly potent and selective inhibitor of HIV replication. Its 50% effective concentration for viral replication in MT-4 cells was 0.07-0.5 nM depending on viral strains, including HIV-2. This concentration was approximately 105-fold lower than its cytotoxic threshold. RD4-2138 was also inhibitory to the syncytium formation induced by cocultivation of Molt-4 cells with Molt-4/IIIB cells (Molt-4 cells chronically infected with HIV-1). Some correlation was observed with the ingenol derivatives between their inhibitory effects on HTLV-IIIB replication and surface CD4 expression in MT-4 cells, suggesting that the mechanism of inhibition is in part attributed to the inhibition of virus adsorption through down-regulation of CD4 molecules in the host cells. However, such correlation was not identified between the inhibition of HTLV-IIIB and the activation of protein kinase C. Thus, they might have a potential as effective anti-HIV agents when toxicity in vivo could be elucidated.

Ceramide limits phosphatidylinositol-3-kinase C2β-controlled cell motility in ovarian cancer: potential of ceramide as a metastasis-suppressor lipid

Targeting cell motility, which is required for dissemination and metastasis, has therapeutic potential for ovarian cancer metastasis, and regulatory mechanisms of cell motility need to be uncovered for developing novel therapeutics. Invasive ovarian cancer cells spontaneously formed protrusions, such as lamellipodia, which are required for generating locomotive force in cell motility. Short interfering RNA screening identified class II phosphatidylinositol 3-kinase C2β (PI3KC2β) as the predominant isoform of PI3K involved in lamellipodia formation of ovarian cancer cells. The bioactive sphingolipid ceramide has emerged as an antitumorigenic lipid, and treatment with short-chain C6-ceramide decreased the number of ovarian cancer cells with PI3KC2β-driven lamellipodia. Pharmacological analysis demonstrated that long-chain ceramide regenerated from C6-ceramide through the salvage/recycling pathway, at least in part, mediated the action of C6-ceramide. Mechanistically, ceramide was revealed to interact with the PIK-catalytic domain of PI3KC2β and affect its compartmentalization, thereby suppressing PI3KC2β activation and its driven cell motility. Ceramide treatment also suppressed cell motility promoted by epithelial growth factor, which is a prometastatic factor. To examine the role of ceramide in ovarian cancer metastasis, ceramide liposomes were employed and confirmed to suppress cell motility in vitro. Ceramide liposomes had an inhibitory effect on peritoneal metastasis in a murine xenograft model of human ovarian cancer. Metastasis of PI3KC2β knocked-down cells was insensitive to treatment with ceramide liposomes, suggesting specific involvement of ceramide interaction with PI3KC2β in metastasis suppression. Our study identified ceramide as a bioactive lipid that limits PI3KC2β-governed cell motility, and ceramide is proposed to serve as a metastasis-suppressor lipid in ovarian cancer. These findings could be translated into developing ceramide-based therapy for metastatic diseases.

Dietary Pulverized Konjac Glucomannan Suppresses Scratching Behavior and Skin Inflammatory Immune Responses in NC/Nga Mice

BACKGROUND

Feeding with pulverized konjac glucomannan (PKGM) suppresses the development of eczema and hyper-IgE production in NC/Nga mice, a model of atopic dermatitis. This study aimed to examine the effects of PKGM on scratching behavior and skin inflammatory immune responses in NC/Nga mice.

METHODS

Four-week-old NC/Nga mice were maintained for 8 or 9 weeks on diet containing PKGM. Scratching behavior and clinical symptoms were evaluated every 2 weeks. Effects of PKGM on cutaneous inflammation were evaluated by histopathological analysis. Local expression levels of substance P and proinflammatory cytokines were measured by ELISA.

RESULTS

An increase in scratching behavior was evident from 6 weeks of age in control mice, but this symptom was dose-dependently inhibited in PKGM-fed mice. Continuous PKGM feeding then significantly inhibited eczematous skin lesions including hyperkeratosis, dermal mastocytosis and eosinophilia. Concomitantly, cutaneous overproductions of substance P, IL-10, IL-4, and TNF-alpha were all suppressed in PKGM-fed mice.

CONCLUSIONS

PKGM feeding markedly suppressed development of scratching behavior, substance P expression with mastocytosis, and skin inflammatory immune responses in NC/Nga mice.

Decrease in the allergenicity of Japanese cedar pollen allergen by treatment with positive and negative cluster ions

BACKGROUND

Japanese cedar pollinosis is a severe allergic disease in Japan. The most effective means of decreasing allergic inflammation reactions is still avoidance of the aeroallergen. Recently, a novel air purification system using positively and negatively charged cluster ions was developed to create comfortable living environments. We aimed to assess the ability of existing technology to lower allergenicity of Japanese cedar pollen.

METHODS

A Japanese cedar pollen extract was nebulized from the top of a cylindrical container with 2 or 4 ion-generating devices. The extract in a mist was passed through the space filled with or without plasma cluster ions for 90 s, and the ion-treated or nontreated extract was then collected in a Petri dish at the bottom of the container.

RESULTS

The ion-exposed extract was significantly diminished in its reactivities to anti-Cry j 1 or anti-Cry j 2 antiserum and to human allergic sera IgE on ELISA. SDS-PAGE analysis revealed that ion exposure induced protein degradation in the pollen extract. Similarly, the ion treatment impaired about 80% of the binding to pooled sera IgE from patients allergic to Japanese cedar pollen on ELISA inhibition. Furthermore, intracutaneous and conjunctival reaction tests showed a remarkable diminution in the allergenicity of the ion-irradiated extract.

CONCLUSION

Ion irradiation resulted in a remarkable decrease in in vitro and in vivo allergenicities of atomized Japanese cedar pollen extracts.

Extracellular secretion of free fatty acids by disruption of a fatty acyl-CoA synthetase gene in Saccharomyces cerevisiae

To elucidate the molecular mechanism governing fatty acid transport across the cell membrane, we first isolated a Saccharomyces cerevisiae mutant, B-1, that exhibits a reduced acyl-CoA oxidase activity and an increase in free fatty acid accumulation. Following mutagenesis of B-1, a mutant, YTS51, which secretes free fatty acids, was isolated. The concentration of free fatty acids in the YTS51 culture medium was about 17 times higher than that in B-1. The mutation that causes the fatty acid secretion phenotype occurred at a single allele, and this phenotype was suppressed by the introduction of a single copy of FAA1, a gene for acyl-CoA Synthetase, to the mutant. Although the mutation expressing this phenotype was not within FAA1 in YTS51, the disruption of FAA1 in the wild-type strain resulted in fatty acid secretion even though the level of fatty acid secretion was less than that in YTS51. We consider that YTS51 is a suitable model to elucidate the molecular basis of the fatty acid transport process.

Toward elucidating the full spectrum of mite allergens--state of the art

Our research has focused on the molecular design of immunotherapeutic vaccines and the advancement of mite-allergy diagnosis. Here, we describe the research history of the major group 1 and group 2 allergens, immunoelectrophoretic analyses covering the complete spectrum of mite allergens, our results on allergens with distinctive characteristics (a conjunctival congestion-eliciting antigen [LM2], an immunotherapeutic antigen [HM2] with high efficacy and without definite adverse reactions, and a potent T-cell stimulatory antigen [HM1] with secretion of IFN-gamma), the full spectrum and immunochemical properties of the major and other important mite allergens (including our newly described allergens: a pan-allergen [tropomyosin, group 10], a potent T-cell stimulatory allergen [M-177, apolipophorin, group 14] and its peptide fragments Mag1 and Mag3, a moderate IgE-binding allergen [gelsolin/villin, group 16], an EF-hand Ca2+-binding allergen [group 17], and a less IgE-binding allergen [heat shock protein 70]), and prospects for the development of immunotherapeutic and diagnostic agents.

Molecular cloning of a class IV chitinase allergen from Japanese cedar (Cryptomeria japonica) pollen and competitive inhibition of its immunoglobulin E-binding capacity by latex C-serum

BACKGROUND

Japanese cedar (Cryptomeria japonica) pollinosis is one of the most prevalent allergic diseases in Japan. Only three C. japonica allergens, Cry j 1, Cry j 2, and CJP-6, have been characterized. The full IgE-binding spectrum of C. japonica pollen allergens demonstrates that many allergens remain to be identified.

OBJECTIVE

The aim of this study was to characterize a novel allergen with a high frequency of IgE binding.

METHODS

The cDNA coding for a high-frequency IgE-binding protein, designated CJP-4, was cloned from the total mRNA of C. japonica pollen. The corresponding native allergen was purified by affinity precipitation with colloidal chitin and gel chromatography. The IgE-binding ability of purified native CJP-4 was characterized by ELISA and ELISA inhibition.

RESULTS

The CJP-4 cDNA encoded 281 amino acids with significant sequence homology to class IV chitinases. Purified native CJP-4, migrated as a homogeneous 34-kDa protein on SDS-PAGE, revealed endochitinase activity on native PAGE. The purified protein displayed the ability to bind IgE from all patients tested (31/31) in ELISA, whereas Cry j 1 bound to IgE at a 71% frequency (22/31). Pre-incubation with latex C-serum completely inhibited the reaction of pooled sera IgE from patients with C. japonica pollinosis and/or latex allergy to purified CJP-4.

CONCLUSION

We identified CJP-4 as a novel and fourth C. japonica chitinase allergen with high IgE-binding frequency. The competitive IgE-binding profile between C. japonica chitinase and latex C-serum indicated that C. japonica chitinase should be an important pan-allergen in C. japonica pollen.

A new immunomodulatory function of low-viscous konjac glucomannan with a small particle size: its oral intake suppresses spontaneously occurring dermatitis in NC/Nga mice

BACKGROUND

Konjac glucomannan (GM) is a well-known dietary fiber with various beneficial functions: the higher viscosity displayed the stronger potency. However, the high-viscous GM powders, ordinary konjac powder and highly purified GM were mostly unsuitable for the application to various food industries. Our aims are to develop new physiological functions of low-viscous GM powder, pulverized GM or re-granulated fine GM, using a murine model of atopic dermatitis.

METHODS

Male 4-week-old NC/Nga mice were fed for 8 weeks on diets containing 5% of two high-viscous and two low-viscous GM powders, respectively.

RESULTS

Striking suppression against the aggravation of dermatitis, the increase in scratching behaviors, and the rise in IgE levels was recognized only in mice fed on the pulverized GM diet, but not in mice fed on the other GM diets or a control diet. Eczema prevention in the fine GM-fed mice was accompanied by a significant decrease in their plasma IFN-gamma levels, a positive regulatory cytokine for atopic skin inflammation.

CONCLUSION

Only the pulverized GM possessed the ability to suppress the development of dermatitis in NC/Nga mice. This is the new immunomodulatory function of low-viscous GM with a small particle size.

Characterization of immunosuppressive factors expressed in serum by rat tolerogenic liver transplantation

BACKGROUND

In a rat tolerogenic model of orthotopic liver transplantation (OLT), recipient serum after OLT (post-OLT serum) possesses strong immunosuppressive activity. This study aimed to identify immunosuppressive factors present in early post-OLT serum.

METHODS

Immunosuppressive activity was evaluated in vitro by inhibition of the mixed-lymphocyte reaction (MLR). Autoantigens recognized by MLR-inhibitory IgG were identified by the internal protein sequencing.

RESULTS

Recipient post-OLT serum inhibited MLR, and OLT-inducible IgG was the major immunosuppressive factor. IgG from post-OLT sera (2 to 3 weeks) specifically reacted to 31; 34; and 73-kd autoantigens on spleen cells. The internal sequences of the 31- and 34-kd antigens coincided completely with those of histone H1 molecules. Immunodepletion of anti-histone H1 antibodies (Abs) from early post-OLT serum abolished the MLR-inhibitory activity. Furthermore, rabbit polyclonal Ab-directed histone H1 not only significantly suppressed rat and human MLR but also prolonged survival of heart allografts. Flow-cytometric analysis revealed that some live PVG splenocytes were stained with antihistone H1 Abs, and that these positive cells increased on Con A stimulation. Western blot analysis indicated that several cross-reactive antigens against anti-histone H1 Abs were found in their membrane fraction.

CONCLUSIONS

In this study we provide evidence that autoreactive Abs, against histone H1 are a major OLT-induced graft survival factor, and may play at least a part in overcoming the acute rejection phase to establish solid allograft tolerance.

LIVER TRANSPLANTATION-INDUCED ANTIHISTONE H1 AUTOANTIBODIES SUPPRESS MIXED LYMPHOCYTE REACTION

BACKGROUND

In a rat model of orthotopic liver transplantation (OLT), recipient serum after OLT (post-OLT serum) has been reported to prevent allograft rejection. However, the molecular identities of immunosuppressive factors, which are in the early stage of post-OLT, remain elusive. This study was aimed to identify immunodominant suppressive factors present in early post-OLT serum.

METHODS

The immunosuppressive activities of post-OLT serum, immunoglobulin (Ig) G-depleted serum, and purified IgG were evaluated in vitro by inhibition of the mixed lymphocyte reaction (MLR). Autoantigens recognized by the MLR-inhibitory IgG in early post-OLT serum were identified by the internal protein sequencing.

RESULTS

Recipient post-OLT serum inhibited MLR, and its immunosuppressive activity vanished by means of the elimination of OLT-inducible IgG. IgG from post-OLT sera (2-3 weeks) specifically reacted to 31-, 34-, and 73-kDa autoantigens on splenic cells. The internal sequences of the doublet 31- and 34-kDa antigens coincided completely with those of histone H1 molecules. The levels of histone H1-specific antibodies were transiently increased to a plateau around 2 to 3 weeks after OLT but decreased in the later tolerogenic phase. Immunodepletion of antihistone H1 autoantibodies from early post-OLT serum abolished the MLR-inhibitory activity. Furthermore, rabbit polyclonal antibody-directed histone H1 not only suppressed MLR but also prolonged allograft survival.

CONCLUSIONS

In this article, the authors provide evidence that autoreactive antibodies against histone H1, which are transiently induced at the early stage by liver transplantation, are a major OLT-induced graft survival factor.

Two-dimensional IgE-binding spectrum of Japanese cedar (Cryptomeria japonica) pollen allergens

BACKGROUND

Japanese cedar (Cryptomeria japonica) pollen is one of the most prevalent sources of the allergens that elicit rhinitis and conjunctivitis. Only Cry j 1 and Cry j 2 have been well characterized as the major allergens of this pollen.

OBJECTIVES

The aims of this study were to complete the repertoire of C. japonica pollen allergens, to investigate their variability with respect to IgE-reactive patterns and to identify the isoforms of Cry j 1 and Cry j 2 by proteome analysis.

METHODS

Proteins in C. japonica pollen separated on two-dimensional (2-D) polyacrylamide gel electrophoresis were immunodetected with IgE in sera of 40 subjects allergic to C. japonica pollen. Mass fingerprinting was used to elucidate the diversity of the major allergens.

RESULTS

2-D immunolabeling with individual patients' sera showed the distinguishable IgE-binding patterns inlaid with 4-87 spots from a total of 131 IgE-binding protein spots. At least 12 Cry j 1 (27.5-75% of IgE-binding frequency) and 3 Cry j 2 (32.5-40%) isoforms were localized. In total, 31 spots were found to be more reactive than the highest IgE-reactive isoform of Cry j 2.

CONCLUSIONS

The proteomics approaches showed great interindividual variation of IgE-binding patterns to C. japonica proteins and contributed to the repertoire of numerous C. japonica allergens other than Cry j 1 and Cry j 2. Protein microsequencing demonstrated more complicated multiplicity in Cry j 1 than previously known and new isoforms in Cry j 2.

The ability of konjac-glucomannan to suppress spontaneously occurring dermatitis in NC/Nga mice depends upon the particle size

Konjac glucomannan (GM) is a well-known dietary fiber with various beneficial functions, which the higher viscous GM is proposed to have the stronger potencies. Application of highly viscous GM to various food industries is limited for the sake of long elapsed time required to solubilize the GM. Thus, the exploration into any physiological function of low-viscous GM remained undone for a long time. Male 4-week-old NC/Nga mice, a model of atopic dermatitis (AD), were fed for 8 weeks on diets containing 5% each of a high-viscous GM powder, ordinary konjac or highly purified GM, and a low-viscous GM powder, pulverized GM or re-granulated fine GM. Striking suppression to the aggravation of dermatitis and the increases in scratching behaviors and IgE levels was significantly observed only in mice fed on the pulverized GM diet, but not in mice fed on the other GM diets or a control diet. We concluded that the low-viscous GM possesses a novel immunoregulatory function and the intensity of the function depends upon the particle size rather than the viscosity.

Grouping newly isolated docosahexaenoic acid-producing thraustochytrids based on their polyunsaturated fatty acid profiles and comparative analysis of 18S rRNA genes

Seven strains of marine microbes producing a significant amount of docosahexaenoic acid (DHA; C22:6, n-3) were screened from seawater collected in coastal areas of Japan and Fiji. They accumulate their respective intermediate fatty acids in addition to DHA. There are 5 kinds of polyunsaturated fatty acid (PUFA) profiles which can be described as (1) DHA/docosapentaenoic acid (DPA; C22:5, n-6), (2) DHA/DPA/eicosapentaenoic acid (EPA; C20:5, n-3), (3) DHA/EPA, (4) DHA/DPA/EPA/arachidonic acid (AA; C20:4, n-6), and (5) DHA/DPA/EPA/AA/docosatetraenoic acid (C22:4, n-6). These isolates are proved to be new thraustochytrids by their specific insertion sequences in the 18S rRNA genes. The phylogenetic tree constructed by molecular analysis of 18S rRNA genes from the isolates and typical thraustochytrids shows that strains with the same PUFA profile form each monophyletic cluster. These results suggest that the C20-22 PUFA profile may be applicable as an effective characteristic for grouping thraustochytrids.

Differential response to low temperature of two Delta6 fatty acid desaturases from Mucor circinelloides

A recently identified Delta6 fatty acid desaturase in Mucor rouxii shows a low sequence homology (approximately 24% at the amino acid level) to that isolated from Mortierella alpina, but is phylogenetically closer to a plant enzyme, suggesting the occurrence of Delta6 desaturase isozymes in Mucorales molds. In the present study, two types of Delta6 desaturases, mcD6-1 ( Mo. alpina type) and mcD6-2 ( M. rouxii type), were cloned from Mucor circinelloides. When the cloned genes were expressed in the yeast Saccharomyces cerevisiae in the presence of a linoleic acid substrate (C18:2Delta9, 12), a newly generated gamma-linolenic acid (C18:3Delta6, 9, 12) was detected in the cells, which confirmed the suspected enzymatic function of the recombinant protein. This is the first report of Delta6 desaturase isozymes present in one organism. Northern analysis demonstrated that the amount of mcD6-2 mRNA was less than half of that of mcD6-1 mRNA in cells grown at 28 degrees C. However, upon cultivation of the cells at 15 degrees C for 0.5-1 h, mcD6-2 mRNA rapidly increased by up to 1.5-fold and then gradually decreased. By contrast, mcD6-1 transcripts levels did not fluctuate significantly for 1 h after the temperature shift, but declined by 75% over the next 2 h. The gamma-linolenic acid content in total fatty acid from M. circinelloides decreased at 28 degrees C, but was maintained at approximately 30% at 15 degrees C. These data suggest that Delta6 desaturase isozymes play physiologically distinct roles in the maintenance of cellular lipids and adaptation to low temperature.

cDNA cloning and functional expression of alpha-glucosidase from Mortierella alliacea

We recently purified an alpha-glucosidase comprising 61-kDa and 31-kDa subunits from the fungus Mortierella alliacea and characterized its soluble starch-hydrolyzing activity. Here, the cDNA coding for this enzyme was cloned, revealing that it encodes a single polypeptide of 1,053 amino acids, with a calculated molecular mass of 117 kDa. Comparison between the deduced amino acid sequence and the partial sequences of the purified enzyme suggested that an immature protein can be converted into the two subunits of mature enzyme by post-translational processing at least three cleavage sites. Heterologous expression of recombinant alpha-glucosidase in yeast gave rise to a significant increase in hydrolytic activity toward maltose and soluble starch, in both intracellular and extracellular fractions. Immunoblot analysis using antiserum against the alpha-glucosidase revealed that the active enzyme expressed in yeast is also composed of two subunits. The yeast expression system provides a model suitable for investigating the polypeptide-processing event and structure-function relationship of the alpha-glucosidase with unique substrate specificity.

Evidence of isozymes for delta6 fatty acid desaturase in rat hepatocytes

The expression of delta6 fatty acid desaturase, previously identified, was suppressed almost completely by hyper expression of the corresponding antisense gene in a transformant of the rat hepatic cell line BRL-3A. Conversion rates of [1-14C] linoleic acid, alpha-linolenic acid, and tetracosapentaenoic acid into the respective delta6 fatty acids were equivalent to those in control cells. This finding suggested that all of these reactions were catalyzed by at least two delta6 desaturase isozymes in rat hepatocytes.

Production of two types of phytase from Aspergillus oryzae during industrial koji making

In our previous study, it was determined that phytase produced by Aspergillus oryzae plays an important role in supplying phosphate to yeast in the process of making sake. During koji making, two types of phytase (Phy-I and Phy-II) are produced. The purified phytases have high thermal and pH stability, in comparison to phytase purified from a submerged culture (ACP-II). In the present study, Phy-I and Phy-II retained their activities for 45 h. The NH2-terminal sequence of Phy-1, which is eight amino acids in length, was identical to that of ACP-II, but the molecular weights of these two forms, as estimated by SDS-PAGE, were quite different from each other (Phy-I, 120 kDa; ACP-II, 58 kDa). From the NH2-terminal amino acid sequence analysis of the predominant phytase (Phy-II), a molecular weight of 116 kDa was expected to reflect a new type of phytase produced only in koji culture. The substrate specificity of Phy-II was sufficiently broad that it hydrolyzed not only phytic acid and p-nitro phenyl phosphate, but also glucose 6-phosphate and glycerol 1-phosphate. In the process of making koji, Phy-I was produced at an early stage, followed by Phy-II; with both phytases being thought to function to hydrolyze phytic acid cooperatively.

Production and properties of phytase and acid phosphatase from a sake koji mold, Aspergillus oryzae

We identified three types of acid phosphatase (ACP-I, ACP-II, and ACP-III) produced by Aspergillus oryzae in a submerged culture using only phytic acid as the phosphorous substrate. The optimum pH for the activities of the three enzymes was in the range of 4.5 to 5.5. Analysis of the substrate specificities of these enzymes revealed that ACP-I and ACP-III were acid phosphatases, and ACP-II was a phytase. These enzymes were produced during different periods of mycelial growth: ACP-II was produced during the early phase of cultivation (around 24 h), and ACP-I was produced between 24 to 72 h. ACP-III was detected after the production of ACP-I and ACP-II had ceased. The release of phosphate from phytic acid was expected to be due to the cooperative hydrolysis of these enzymes.

Purification and characterization of a novel fungal alpha-glucosidase from Mortierella alliacea with high starch-hydrolytic activity

The fungal strain Mortierella alliacea YN-15 is an arachidonic acid producer that assimilates soluble starch despite having undetectable alpha-amylase activity. Here, a alpha-glucosidase responsible for the starch hydrolysis was purified from the culture broth through four-step column chromatography. Maltose and other oligosaccharides were less preferentially hydrolyzed and were used as a glucosyl donor for transglucosylation by the enzyme, demonstrating distinct substrate specificity as a fungal alpha-glucosidase. The purified enzyme consisted of two heterosubunits of 61 and 31 kDa that were not linked by a covalent bond but stably aggregated to each other even at a high salt concentration (0.5 M), and behaved like a single 92-kDa component in gel-filtration chromatography. The hydrolytic activity on maltose reached a maximum at 55 degrees C and in a pH range of 5.0-6.0, and in the presence of ethanol, the transglucosylation reaction to form ethyl-alpha-D-glucoside was optimal at pH 5.0 and a temperature range of 45-50 degrees C.

A high-molecular-weight mite antigen (HM1) fraction aggravates airway hyperresponsiveness of allergic mice to house dusts and whole mite cultures

BACKGROUND

The house dust mite Dermatophagoides farinae is the most common aeroallergen causing human allergic asthma. Previously, we demonstrated that a high-molecular-weight allergenic fraction (HM1), which was abundant in D. farinae extracts, induced a proliferative response of T cells from healthy donors. The induction was mediated through the activation of macrophages without MHC class II restriction. In this study, we investigate whether HM1 influences the development of airway inflammation in murine models of asthma.

METHODS

BALB/c mice were injected twice intraperitoneally with D. farinae fecal extract (Dff) at an interval of 5 days. They were exposed daily to aerosolized antigen (group 1: Dff, group 2: HM1, group 3: HM1-depleted Dff and group 4: PBS) for 10 days. The effect of HM1 on their airway inflammation was evaluated by measuring acetylcholine-induced airway hyperresponsiveness and inflammatory cell infiltration in lung tissue.

RESULTS

The inhalation of the whole fecal extract or the HM1 fraction induced airway hyperresponsiveness which was detectable after 24 h and was maintained for as long as 120 h. The inhalation of extract depleted of the HM1 fraction induced hyperresponsiveness measured at 24 h but this was not maintained for 120 h. Macrophage infiltration was significantly prolonged in mice inhaling the whole extract and the HM1 fraction compared to the HM1-depleted extract.

CONCLUSION

The inhalation of the high-molecular-weight HM1 fraction of D. farinae prolonged airway hyperresponsiveness and macrophage inflammation in a mouse model of hypersensitivity. The results indicate that the HM1 fraction which can induce T cell proliferation through macrophage activation may play a role in the duration of airway responsiveness.

Molecular cloning and characterization of a new Japanese cedar pollen allergen homologous to plant isoflavone reductase family

BACKGROUND

Japanese cedar (Cryptomeria japonica) pollen is a major cause of seasonal pollinosis, and more than 10% of Japanese people suffer from this allergic disorder. However, only two major pollen allergens, Cry j 1 and Cry j 2, have been identified and exclusively characterized.

OBJECTIVE

The aim of this study was to explore and identify important Japanese cedar pollen allergens other than Cry j 1 or Cry j 2.

METHODS

C. japonica cDNA library was immunoscreened by rabbit antiserum raised against a partially purified cedar pollen allergen fraction. An isolated cDNA clone was inserted into a glutathione S-transferase (GST)-tagged Escherichia coli expression vector to obtain recombinant GST fusion protein. Non-fusion recombinant protein was purified by glutathione Sepharose affinity chromatography in conjunction with factor Xa cleavage of the GST moiety. IgE-binding ability of the recombinant protein was then evaluated by western blot analysis and enzyme-linked immunosorbent assay (ELISA).

RESULTS

The cDNA encodes 306 amino acids with significant sequence similarity to those of plant isoflavone reductase-like proteins, which include a recently identified birch pollen allergen Bet v 5. Western blot analysis demonstrated that recombinant protein was recognized by cedar pollinosis patient IgE. In contrast to Bet v 5 being reported as a minor allergen, the recombinant protein exhibited 76% IgE binding frequency (19/25) against pollinosis patients.

CONCLUSION

Here we identified the third member of Japanese cedar pollen allergen homologous to isoflavone reductase. Its high IgE-binding frequency implicates that the isoflavone reductase homologue might be an additional major pollen allergen in C. japonica.

Herpesvirus DNA in peripheral blood mononuclear cells of some patients with Meniere's disease

Herpes simplex virus-1 (HSV) or varicella zoster virus (VZV) DNA was detected by nested polymerase chain reaction in peripheral blood mononuclear cells of patients with Meniere's disease (one of 28 patients for HSV-1, 2 of 28 patients for VZV) during acute illness (within 5 days after onset). On the other hand, neither HSV-1 DNA or VZV DNA was detected in PBMCs of 50 age- and sex-matched healthy individuals and 50 pregnant women. These findings may imply that reactivation of HSV- 1 or VZV may be associated with the development of some cases of Meniere's disease.

Der f 16: a novel gelsolin-related molecule identified as an allergen from the house dust mite, Dermatophagoides farinae

Allergen from the house dust mite (Dermatophagoides sp.) is a major trigger factor of allergic disorders, and its characterization is crucial for the development of specific diagnosis or immunotherapy. Here we report the identification of a novel dust mite (Dermatophagoides farinae) antigen whose primary structure belongs to the gelsolin family, a group of actin cytoskeleton-regulatory proteins. Isolated mite cDNA, termed Der f 16, encodes 480 amino acids comprising a four-repeated gelsolin-like segmental structure, which is not seen in conventional gelsolin family members. Enzyme immunoassay indicated that recombinant Der f 16 protein, prepared using an Escherichia coli expression system, bound IgE from mite-allergic patients at 47% (8/17) frequency. This is the first evidence that the gelsolin family represents a new class of allergen recognizable by atopic patient IgE.

Induction of a proliferative response of T cells by a high-molecular antigen in Dermatophagoides farinae feces

BACKGROUND

We have previously demonstrated that high-molecular mite antigen (HM1) from Dermatophagoides farinae feces is an allergen which binds to mite-allergic patients IgE. HM1 also induced a proliferative response in lymph node cells from mite-immunized mice as well as nonimmunized mice. In the present study, we demonstrated that HM1 induced T cell proliferation and investigated the HM1-stimulated T cell proliferative pathways using nonallergic human peripheral blood mononuclear cells (PMBC).

METHODS

Blood samples were obtained from 10 healthy donors. Using primary culture, T cell response stimulated with HM1 was performed on purified T cells, CD19+ cell-depleted PBMC and CD11b+ cell-depleted PBMC. In addition, interleukin (IL)-5 and interferon (IFN)-gamma produced by mite-allergic and healthy donors stimulated with HM1 were estimated by enzyme immunoassay.

RESULTS

T cell proliferation was detected only in CD19+ cell-depleted PBMC. When T cells were cocultured with CD11b+ cells they recovered their proliferative response to HM1. In addition, the pathway of HM1-stimulated T cell proliferation did not involve HLA class II restriction. Both activated CD11b+ cells and their conditioned media were needed to induce HM1-stimulated T cell proliferation. Furthermore, HM1 induced IFN-gamma production in both healthy and allergic donors.

CONCLUSION

The high-molecular mite antigen, HM1, induced a proliferative response of T cells in healthy as well as allergic donors, without HLA class II restriction. Our results suggest that further investigation of HM1 could constitute a valuable avenue of research into complex allergic diseases.

Targets of anti-influenza chemotherapy other than neuraminidase and proton pump

Antiviral chemotherapy for influenza started with treatment with amantadine and then progressed with finding the clinical efficacy of neuraminidase (NA) inhibitors. Beside amantadine and NA inhibitors, there are several compounds that attack novel targets of influenza virus (FluV) replication. Binding and penetration of FluV to cell membrane are important stages in the process of virus replication, and several compounds that inhibit these functions have been reported, although most of them have yet to be examined for clinical use. A polyoxometalate (PM523) was shown to be potent inhibitor of FluV A, respiratory syncytial virus and measles virus, and was shown to inhibit membrane fusion between FluV envelope and the cellular membrane. Strains of virus with acquired resistance to PM523 had mutations in the amino acids substrates in HA1 head, and amino acid changes occurred in the interface peptide of the trimers of HA. Cap formation of FluV-encoded mRNA is unique; it utilizes 5'-mGpppXm of host mRNA. Several substances which inhibit the cap formation of FluV (they are inhibitors of PB2 enzyme activity of FluV) are introduced and reviewed in this article. A metabolic product of ribavirn, 1,2,4 triazole carboxamide (T-CONH2) is inhibitory for FluV A growth in vitro. Peroral administration of TCONH2 also showed therapeutic effect in an experimental mouse infection model of FluV A as well as ribavirin. TCONH2 seems to be less toxic than ribavirin for mice, and may be useful as alternative chemotherapy of ribavirin. Other anti-FluV substances that have been reported to be effective for FluV infection in the mouse are discussed with respect to the possibility of their clinical potential.

Identification and expression of a rat fatty acid elongase involved in the biosynthesis of C18 fatty acids

A major part of the palmitic acid (C16:0) generated by fatty acid synthase is converted into stearic acid (C18:0) via carbon chain elongation. Here, we describe the cloning and expression of a rat hepatic enzyme, rELO2, responsible for the elongation of C16:0, presumably at the condensing reaction. Heterologous expression experiments in a yeast, Saccharomyces cerevisiae, demonstrated the elongation activity of rELO2 on C16:0 and to a lesser extent, C18:0 and fatty acids with low desaturation degree. This was distinct from that rELO1, a rat homolog of HELO1, which preferably catalyzed the elongation of mono- and polyunsaturated fatty acids of C16-C20. The Northern analysis showed that the expression of rELO2, but not rELO1, in hepatocytes was activated by the cycles of fasting and refeeding rats on a fat-free diet. Under these conditions, the rELO1 was expressed constitutively in various tissues but the rELO2 transcripts were detected predominantly in liver.

Synthesis and antiherpesvirus activities of 5-alkyl-2-thiopyrimidine nucleoside analogues

Twenty 5-alkyl-2-thiopyrimidine nucleosides were newly synthesized and examined for antiviral activities against herpes simplex virus (HSV), varicella-zoster virus (VZV) and human cytomegalovirus (HCMV). In this study, 2'-deoxy-5-alkyl-2-thiocytidine analogues had lower 50% effective concentration (EC50) values against HSV-1, and 2'-deoxy-5-alkyl-2-thiouridine analogues showed lower EC50 against VZV than their congeners of arabinoside form. Among the compounds examined, 2'-deoxy-5-ethyl and 5-propyl-2-thiocytidine (TN-53 and TN-54) were most potent and selective anti-HSV compounds. Their EC50s were 0.04 and 0.15 microM, and selectivity indexes were more than 7,215 and 1,849, respectively. On the other hand, 2'-deoxy-5-propyl-2-thiouridine (TN-51), 5-bromovinyl-2-thiouracil arabinoside (TN-65) and 5-styryl-2-thiouracil arabinoside (TN-67) were most potent and selective anti-VZV compounds. Their EC50s were 3.1, 3.8 and 2.6 pM for CaQu strain of VZV, respectively, and 2.1 to 3.0 times lower than that of acyclovir. All 2-thiopyrimidine nucleoside analogues did not show antiviral activities against thymidine kinase (TK) negative strains of HSV-1 and VZV. Only three 2-thiocytosine arabinoside compounds showed marginal anti-CMV activities (EC50s were 57-159 pM). All of the five alkyl-2-thio-pyrimidine nucleoside analogues examined were not cytotoxic to human lymphoblastoid cells (RPM18226) and human embryonic fibroblast cells (MRC-5) at 240 microM (100 microg/ml) or more. Regarding the structure-activity relationship of 5-alkyl-2-thiopyrimidine nucleoside analogues, the following remarks will be noted. Elongation of 5-alkyl chain (methyl to ethyl) of 2-thiocytosine in both deoxyribosyl and arabinosyl nucleosides increased anti-HSV-1 activity but not anti-VZV activity. Furthermore, elongation of the same chain (ethyl to propyl) of 2-thiodeoxyuridine increased anti-VZV activity whereas it did not in the case of 2-thiouracil arabinosides.

Mechanism of selective inhibition of respiratory syncytial virus by a benzodithiin compound (RD3-0028)

RD3-0028, a compound with a benzodithiin structure, was found to be a potent inhibitor of respiratory syncytial virus (RSV) replication. Its action is specific; no activity is seen against influenza A virus, measles virus, herpes simplex virus type 1 or 2, or human cytomegalovirus. A time-dependent drug addition experiment indicated that the antiviral activity occurs in the late stage of the RSV replication cycle, since this compound completely inhibited syncytium formation even when added up to 16 hr after the infection of cell monolayers at an MOI of 3. RD3-0028 had no direct virucidal effect on RSV. Western blotting analysis showed that RD3-0028 significantly decreased the amount of RSV proteins released into the cell culture medium. Moreover, five independent isolates of the RSV long strain were selected for growth in RD3-0028 (5-20 microg/ml). These resistant viruses were more than 80-fold less sensitive to RD3-0028 than the long strain. The F gene segment of each of these viruses was sequenced and in each case the mutant RNA segment contained at least one sequence alteration, converting asparagine 276 to tyrosine (F1 protein). These results suggest that RD3-0028 inhibits RSV replication by interfering with intracellular processing of the RSV fusion protein, or a step immediately thereafter, leading to loss of infectivity.

Pharmacokinetics of a benzodithiin (RD3-0028) following aerosol treatment in rat

1. RD3-0028, a benzodithiin compound, has potent antiviral activity against respiratory syncytial virus (RSV) in cell culture. The compound also inhibits growth of RSV and improves pathologic changes of interstitial pneumonia in the immunosuppressed mouse when delivered by small-particle aerosol. 2. In the present study, the absorption, distribution and excretion of 14C-RD3-0028 were compared in rat following either a single aerosol treatment or oral administration. 3. The plasma concentration was maintained at the same level from 5 min to 1 h, and decreased with a half-life of 2.2 +/- 0.1 h for 1-8 h. 4. The excretion of radioactivity in the urine and faeces at 24 h after aerosol treatment was 89.3 and 4.5%, respectively, indicating that almost all the radioactivity was rapidly excreted in the urine. The excretion of total radioactivity was 98.9% within 168 h. 5. The concentrations of radioactivity in the lung and trachea following aerosol treatment were higher than those in other tissues, and were detected even at 72 h. 6. These results suggest that the aerosol treatment might be useful for delivering RD3-0028 to the respiratory tract of RSV-infected patients.

Antiviral activity of NMSO3 against adenovirus in vitro

NMSO3, a sulfated sialyl lipid, was evaluated for its efficacy against adenovirus (AdV) in vitro. The median effective concentration (50% effective concentration, EC(50)) of NMSO3 against replication of AdV type 2 (AdV2), type 4 (AdV4), type 8 (AdV8) and type 37 (AdV37) was 0.21-0.71 microg/ml in HEp-2 cells and 1.01-1.41 microg/ml in MKN-28 cells. The EC(50) values of NMSO3 were lower than those of HPMPC and ddC, which were also evaluated. NMSO3 exhibited minimal cytotoxicity against HEp-2 cells and MKN-28 cells, both for which the median cytotoxic concentration (50% cytotoxic concentration, CC(50)) was more than 1000 microg/ml. NMSO3 was the most potent and selective anti-AdV compound of those examined. NMSO3 inhibited AdV infection of HEp-2 cells only when present during the virus adsorption period. A virus binding assay using radiolabeled AdV4 revealed that NMSO3 inhibited viral binding to the HEp-2 cells. NMSO3 itself bound to the virus particles, but not to the HEp-2 cell membrane. Thus, the mechanism of anti-AdV activity by NMSO3 involves inhibition of virus adsorption to cells by NMSO3 binding to viral particles.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1999). III. Secular changes in susceptibility]

The bacteria (Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Klebsiella spp. and Pseudomonas aeruginosa) isolated from patients diagnosed as having urinary tract infections (UTIs) in 9 institutions in Japan were supplied between the period of August 1999 to July 2000. Then, the susceptibilities of these bacteria to various antimicrobial agents were examined and the results were compared with those obtained between 1991 and 1998. Comparison was made by classifying strains isolated from patients into those with uncomplicated UTIs and those with complicated UTIs (including with or without indwelling catheter). About E. faecalis, increase of low sensitive strains noted in the former year showed a decreasing tendency, however, one strain each with MIC of 4 micrograms/ml to vancomycin (VCM) was detected in patients with both uncomplicated and complicated UTIs. As for S. aureus, many sensitive strains to cephems, imipenem (IPM) and VCM were noted, and each MIC50 was better than that in the former years. S. aureus strains showing low susceptibility to arbekacin (ABK) were detected in patients with complicated UTIs in this year as well as in the former year, and one strain each with MIC of 16 micrograms/ml and 32 micrograms/ml was detected. Susceptibilities of E. coli were effective to all drugs except for penicillins and minocycline (MINO). Decrease of low sensitive strains was also noted in all drugs except for quinolones. Each MIC90 of ciprofloxacin (CPFX) and sparfloxacin (SPFX) in patients with complicated UTIs against E. coli was 3 degrees classes lower than that in patients with uncomplicated UTIs. As for Klebsiella pneumoniae, decrease of low sensitive strains to cephems was noted in patients with uncomplicated UTIs in 1998. In 1999, low sensitive strains decreased also in patients with complicated UTIs, and few were detected. Susceptibilities of K. pneumoniae to quinolones were effective as compared with those in the former years with the MIC80s of 0.125 microgram/ml or below without detection of low sensitive strains. One low sensitive strain of K. pneumoniae with MIC of 8 micrograms/ml was detected for gentamicin (GM). Susceptibilities of P. aeruginosa to carbapenems were notable. The MIC90 of meropenem (MEPM) and IPM was 4 micrograms/ml each which was 2 degrees better than that in 1998. Resistant P. aeruginosa strains to other drugs except for monobactams decreased in 1999.

4'-Ethynyl nucleoside analogs: potent inhibitors of multidrug-resistant human immunodeficiency virus variants in vitro

A series of 4'-ethynyl (4'-E) nucleoside analogs were designed, synthesized, and identified as being active against a wide spectrum of human immunodeficiency viruses (HIV), including a variety of laboratory strains of HIV-1, HIV-2, and primary clinical HIV-1 isolates. Among such analogs examined, 4'-E-2'-deoxycytidine (4'-E-dC), 4'-E-2'-deoxyadenosine (4'-E-dA), 4'-E-2'-deoxyribofuranosyl-2,6-diaminopurine, and 4'-E-2'-deoxyguanosine were the most potent and blocked HIV-1 replication with 50% effective concentrations ranging from 0.0003 to 0.01 microM in vitro with favorable cellular toxicity profiles (selectivity indices ranging 458 to 2,600). These 4'-E analogs also suppressed replication of various drug-resistant HIV-1 clones, including HIV-1(M41L/T215Y), HIV-1(K65R), HIV-1(L74V), HIV-1(M41L/T69S-S-G/T215Y), and HIV-1(A62V/V75I/F77L/F116Y/Q151M). Moreover, these analogs inhibited the replication of multidrug-resistant clinical HIV-1 strains carrying a variety of drug resistance-related amino acid substitutions isolated from HIV-1-infected individuals for whom 10 or 11 different anti-HIV-1 agents had failed. The 4'-E analogs also blocked the replication of a non-nucleoside reverse transcriptase inhibitor-resistant clone, HIV-1(Y181C), and showed an HIV-1 inhibition profile similar to that of zidovudine in time-of-drug-addition assays. The antiviral activity of 4'-E-thymidine and 4'-E-dC was blocked by the addition of thymidine and 2'-deoxycytidine, respectively, while that of 4'-E-dA was not affected by 2'-deoxyadenosine, similar to the antiviral activity reversion feature of 2',3'-dideoxynucleosides, strongly suggesting that 4'-E analogs belong to the family of nucleoside reverse transcriptase inhibitors. Further development of 4'-E analogs as potential therapeutics for infection with multidrug-resistant HIV-1 is warranted.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1999). II. Background of patients]

Five-hundred forty four bacterial strains isolated from 412 patients diagnosed as having urinary tract infections (UTIs) in 9 institutions in Japan were supplied between the period of August 1999 to July 2000. Then, the clinical background of patients were investigated such as sex, age and type of infections, infections and kind of bacteria, frequency of isolation of bacteria by age and infections, bacteria and infections by timing of administration of antibiotics, and bacteria and infections by surgical procedures. About the relationship between age and sex of patients and type of infections, the number of male patients aged less than 50 years was few, and complicated UTIs without indwelling catheter was the most frequent. In females, the number of patients aged less than 20 years was few. Complicated UTIs without indwelling catheter was the most frequent among female patients aged between 40 to 59 years, in other age groups, uncomplicated UTIs was most frequent. As for type of infections and kind of bacteria, Escherichia coli decreased when the infections became complicated, and Pseudomonas aeruginosa and Enterococcus faecalis increased when the infection became complicated. Considering this result by age of patients, isolation frequency of E. coli was gradually decreased with aging in patients aged more than 20 years with uncomplicated UTIs or complicated UTIs without indwelling catheter. The isolation frequencies of E. faecalis and Staphylococcus aureus were gradually increased with aging in complicated UTIs without indwelling catheter. In patients with complicated UTIs with indwelling catheter, there was no difference between age group, and P. aeruginosa and E. faecalis were frequently isolated. As for type of causative organisms in UTIs before and after the administration of antibiotics, the isolation of bacteria was remarkably decreased after administration in patients with uncomplicated UTIs and complicated UTIs without indwelling catheter. E. coli decreased after administration of antibiotics, and P. aeruginosa and E. faecalis increased after administration in patients with all infections. As for type of causative organisms in UTIs and surgical procedures, E. coli were more frequently isolated in patients with uncomplicated UTIs when surgical procedures were experienced. Also, Klebsiella spp. and E. faecalis were more frequently isolated in patients with surgical procedures. However, in complicated UTIs, type of causative organisms had no relationship with surgical procedures.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1999). I. Susceptibility distribution]

The bacterial strains isolated from patients diagnosed as having urinary tract infections (UTIs) in 9 institutions in Japan were supplied between the period of August 1999 to July 2000. Then, the susceptibilities of them to many kinds of antimicrobial agents were investigated. The number of them were 499 strains. The breakdown of these strains was Gram-positive bacteria as 31.3% and Gram-negative bacteria as 68.7%. Susceptibilities of these bacteria to antimicrobial agents were as follows; vancomycin (VCM), ampicillin (ABPC) and imipenem (IPM) showed strong activities against Enterococcus faecalis. The increase of low-susceptible strains which was noticed in the former year showed a slight recovery in this year. VCM showed a strong activity against MRSA preventing growth of all strains with 1 microgram/ml. In addition, the activity of arbekacin (ABK) was also strong with the MIC90 of 2 micrograms/ml against MRSA. However, MSSA and MRSA showing low susceptibilities were detected in one strain each (MIC: 16 micrograms/ml and 32 micrograms/ml, respectively). Carbapenems showed high activities against Citrobacter freundii and Escherichia coli. Meropenem (MEPM) prevented growth of all strains within 0.125 microgram/ml. Quinolone resistant E. coli decreased in this year compared with those in the last year, that percentage was less than 5%. Almost all drugs showed strong activities against Klebsiella pneumoniae and Proteus mirabilis. MEPM and carumonam (CRMN) prevented growth of all strains within 0.125 microgram/ml. On the other hand, one strain of K. pneumoniae showing resistance to cefaclor (CCL) and one strain of P. mirabilis showing low susceptibility to most of cephems were detected. Against Pseudomonas aeruginosa, almost drugs were not so active. The MIC90s of carbapenems were 8 micrograms/ml and those of all other drugs were more than 16 micrograms/ml.