Molecular tweezers - a new class of potent broad-spectrum antivirals against enveloped viruses.

A new supramolecular approach to broad spectrum antivirals utilizes host guest chemistry between molecular tweezers and lysine/arginine as well as choline. Basic amino acids in amyloid-forming SEVI peptides (semen-derived enhancers of viral infection) are included inside the tweezer cavity leading to disaggregation and neutralization of the fibrils, which lose their ability to enhance HIV-1/HIV-2 infection. Lipid head groups contain the trimethylammonium cation of choline; this is likewise bound by molecular tweezers, which dock onto viral membranes and thus greatly enhance their surface tension. Disruption of the envelope in turn leads to total loss of infectiosity (ZIKA, Ebola, Influenza). This complexation event also seems to be the structural basis for an effective inihibition of cell-to-cell spread in Herpes viruses. The article describes the discovery of novel molecular recognition motifs and the development of powerful antiviral agents based on these host guest systems. It explains the general underlying mechanisms of antiviral action and points to future optimization and application as therapeutic agents.

A molecular tweezer antagonizes seminal amyloids and HIV infection.

Semen is the main vector for HIV transmission and contains amyloid fibrils that enhance viral infection. Available microbicides that target viral components have proven largely ineffective in preventing sexual virus transmission. In this study, we establish that CLR01, a 'molecular tweezer' specific for lysine and arginine residues, inhibits the formation of infectivity-enhancing seminal amyloids and remodels preformed fibrils. Moreover, CLR01 abrogates semen-mediated enhancement of viral infection by preventing the formation of virion-amyloid complexes and by directly disrupting the membrane integrity of HIV and other enveloped viruses. We establish that CLR01 acts by binding to the target lysine and arginine residues rather than by a non-specific, colloidal mechanism. CLR01 counteracts both host factors that may be important for HIV transmission and the pathogen itself. These combined anti-amyloid and antiviral activities make CLR01 a promising topical microbicide for blocking infection by HIV and other sexually transmitted viruses.

[No HCV seroconversion in hemophilia following substitution with virus-inactivated coagulation factor VIII and IX concentrates]. / Keine HCV-Serokonversion bei Hämophilen nach Substitution mit Viren-inaktivierten Gerinnungsfaktor VIII- und IX-Konzentraten.

Since 1986 the factor VIII and IX concentrates of the Central Laboratory, Swiss Red Cross Blood Transfusion Service have been virus inactivated with tri-(n-butyl) phosphate and Tween 80. Clinical studies had shown that both preparations were well tolerated and hemostatically effective; no HIV infection was transmitted. However, safety from transmission of non-A/non-B hepatitis could not be shown since the study included no previously untreated patients. In the meantime, a laboratory test has become available which allows retrospective testing for anti-hepatitis C antibodies in frozen sera of the study patients. 5 of the 26 patients, observed during a 2-year follow-up study, had no HCV antibodies before entering the long-term trial. During this trial, each of these 5 patients substituted an average quantity of 40,200 coagulation factor units (7500-69,000) from 45 production lots. None of these 5 patients developed anti-HCV antibodies, nor did any of them show clinical signs of infection with hepatitis. This suggests that virus inactivation using solvent/detergent treatment reduces the risk of transmission of HCV.

Viral inactivation of intramuscular immune serum globulins.

A new process for the production of intramuscular immunoglobulin products is described which includes viral inactivation through solvent-detergent treatment. Removal of solvent-detergent was accomplished by precipitation, filtration and diafiltration. Process-scale preparations had appropriate antibody potency levels, and improved IgG integrity relative to traditional IGIM products. Moreover, acceptable results were obtained in all in vitro and in vivo pre-clinical toxicology testing, as well as clinical evaluation. Scaled-down experiments demonstrated that the new process provides effective viral inactivation. Taken together, these results indicate that the new products should have the same efficacy of the previous IGIM products albeit with safety and processing improvements.

Effect of manufacturing process parameters on virus inactivation by solvent-detergent treatment in a high-purity factor IX concentrate.

BACKGROUND AND OBJECTIVES: Treatment with solvent-detergent is widely used for ensuring the virus safety of plasma products. Laboratory studies have shown this procedure to be effective for inactivating enveloped viruses under manufacturing conditions. In the present study, the effect of different manufacturing process parameters on virus inactivation by treatment with polysorbate 80 and tri-n-butyl phosphate were investigated for a high-purity factor IX concentrate in order to evaluate the robustness of this step. MATERIALS AND METHODS: Samples of factor IX intermediate were obtained, virus was added and the kinetics of virus inactivation followed during incubation. The effect of altering the conditions on virus inactivation was tested. RESULTS: Solvent-detergent treatment was confirmed to effectively inactivate, i.e. by > or = 5 log, a wide range of representative enveloped viruses under standard conditions. Virus inactivation was consistently effective in a number of different manufacturing batches. Of the parameters tested, only solvent-detergent concentration and temperature significantly effected virus inactivation. CONCLUSIONS: The robustness of the solvent-detergent step for virus inactivation has been confirmed. Using the data generated, appropriate limits can be set for this manufacturing process step.