Enveloped viruses

In order to enhance the stability of hposomes and to provide a biocompatible outermost surface shucture for controlled immobihzation (see Section IV), isolated monomeric and oligomeric S-layer protein from B. coagulans E38/vl [118,123,143], B. sphaericus CCM 2177, and the SbsB from B. stearothermophilus PV72/p2 [119] have been crystallized into the respective lattice type on positively charged liposomes composed of DPPC, HD A, and cholesterol. Such S-layer-coated hposomes are spherical biomimetic structures (Fig. 18) that resemble archaeal ceUs (Fig. 14) or virus envelopes. The crystallization of S-... 

Roux KH, Taylor KA (2007) AIDS virus envelope spike structure. Curr Opin Struct Biol 17 244-252 Sacktor N, Haughey N, Cutler R, Tamara A, Turchan J, Pardo C, Vargas D, Nath A (2004) Novel markers of oxidative stress in actively progressive HIV dementia. J Neuroimmunol 157 176-184 Samson M, LaRosa G, Libert F, Paindavoine P, Detheux M, Vassart G, Parmentier M (1997) The second extraceUular loop of CCR5 is the major determinant of ligand specificity. J Biol Chem 272 24934-24941... 

Paramyxoviruses Mumps virus Enveloped particles variable in size, 110-170nm in diameter, with helical capsids Infection in children produces characteristic swelling of parotid and submaxillary salivary glands. The disease can have neurological complications, e.g. meningitis, especially in adults... 

Measles virus Enveloped particles variable in size, 120-250nm in diameter, helical capsids Very common childhood fever, immunity is life-long and second attacks are very rare... 

Arthos J, Rubbert A, Rabin RL, et al. CCR5 signal transduction in macrophages by human immunodeficiency virus and simian immunodeficiency virus envelopes. J Virol 2000 74(14) 6418-6424. 

Enveloped viruses Many viruses have complex membranous structures surrounding the nucleocapsid. Enveloped viruses are common in the animal world (for example, influenza virus), but some enveloped bacterial viruses are also known. The virus envelope consists of a lipid bilayer with proteins, usually glycoproteins, embedded in it. Although the glycoproteins of the virus membrane are encoded by the virus, the lipids are derived from the membranes of the host cell. The symmetry of enveloped viruses is expressed not in terms of the virion as a whole but in terms of the nucleocapsid present inside the virus membrane. 

Gitman, A.G., Kahane, L., and Loyter, A. (1985a) Use of virus-attached antibndies or insulin molecules to mediate fusion between Sendai virus envelopes and neuraminidase-treated cells. Biochemistry 24, 2762-2768. 

Gitman, A.G., Graessmann, A., and Loyter, A. (1985b) Targeting of loaded Sendai virus envelopes by covalently attached insulin molecules to virus receptor-depleted cells Fusion-mediated microinjection of ricin A and simian 40 DNA. Proc. Natl. Acad. Sci. USA 82, 7209-7313. 

The trisaccharide-hexapeptide partial structure (151) of aleukemia-virus envelope glycoprotein, which was obtained from 46 (see Section 11,2) via saccharide and carboxyl deprotection, has also been coupled to BSA to furnish a synthetic glycoprotein 152 containing 12% of carbohydrate in the form of the trisaccharide (19). 

Yeast expression vectors have been among those most commonly used since the beginning of gene technology. Vectors based on baker s yeast, Saccharomyces cerevisiae, have been especially popular for robust expression of many types of recombinant proteins [90]. For instance, the first commercially available recombinant vaccine, the hepatitis B surface antigen vaccine, was produced from an S. cerevisiae vector [91]. Many other recombinant proteins have also been efficiently expressed in yeast including al-Antitrypsin [92], insulin [93], Epstein-Barr virus envelope protein [94], superoxide dismutase [95] and interferon-a [90]. 

Prange, R., and Streeck, R. (1995). Novel transmembrane topology of the hepatitis B virus envelope proteins. EMBO J. 14, 247-256. 

Immunopotentiating reconstituted influenza virosomes (IRTV) are spherical 150-nm sized particles consisting of a phospholipid bilayer in which influenza virus A/Singapore strain-derived hemagglutinin (HA) and neuraminidase (NA) are intercalated. As such, they resemble and mimic the influenza virus envelope. The difference from conventional liposome formulations lies in the inclusion of the viral envelope proteins HA and NA as well as viral phospholipids. Especially, the inclusion of influenza virus HA provides IRIV with delivery and immimogenic capacities. IRTV are licensed for human use as adjuvant in hepatitis A vaccination and as influenza subunit vaccine (1). 

Modification of Cells for Transport Experiments Experimental control of intracellular environment, 171, 817 implantation of isolated carriers and receptors into living cells by Sendai virus envelope-mediated fusion, 171, 829 resonance energy transfer microscopy visual colocalization of fluorescent lipid probes in liposomes, 171, 850. 

RM Marks, H Lu, R Sundaresan, T Toida, A Suzuki, T Imanari, MJ Hernaiz, RJ Linhardt. Probing the interaction of dengue virus envelope protein with heparin assessment of glycosaminoglycan-derived inhibitors. J Med Chem 44 2178-2187, 2001. 

The antigenic activity of the keratan sulfate-like, protein complex from chick allantoic fluid results mainly from the presence of relatively large proportions of prosthetic groups (hexasaccharides) that differ greatly from that usually described as keratan sulfate.293 This complex is immunologically identical with a component of influenza-virus envelope.294... 

Wyatt, J.R., Vickers, T.A., Roberson, J.L., Buckheit, R.W.J., Klimkait, T., DeBaets, E. et al. (1994) Combinatorially selected guanosine-quartet structure is a potent inhibitor of human immunodeficiency virus envelope-mediated cell fusion. Proc. Natl. Acad. Sci. USA, 91, 1356-1360. 

Y. Kaneda, Virus (Sendai virus envelopes) mediated gene transfer, Cell Biology A Laboratory Handbook (J. E. Celis, ed.) vol. 3. Academic Press, San Diego, 1994, pp. 50-57. 

A natural SP OKU-40 was extracted from the marine microalga Dinoflag-ellata and was found to inhibit the replication of HIV, RSV, influenza A and B viruses, measles virus, and parainfluenza viruses type 2 (PIV-2). However, it did not inhibit the replication of mumps virus or PIV-3 [98]. The action of negatively charged polysaccharides is not merely one of nonspecific inhibition of the binding of an enveloped virus to receptors. In fact, OKU-40 did not inhibit the binding of HIV or influenza A virus to the cell membrane, but it did inhibit the fusion of the membranes of HIV-infected MOLT-4 cells to those of uninfected cells and the fusion of the influenza A virus envelope to uninfected MDCK cells [99]. 

Leonard CK, Spellman MW, Riddle L, Harris RJ, Thomas JN, Gregory TJ (1990), Assignment of intrachain disulfide bonds and characterization of potential glycosylation sites of the type 1 recombinant human immunodeficiency virus envelope glycoprotein (gpl20) expressed in Chinese hamster ovary cells, J. Biol. Chem. 

Kaur, R., Rauthan, M., and Vrati, S. (2004), Immunogenicity in mice of a cationic microparticle-adsorbed plasmid DNA encoding Japanese encephalitis virus envelope protein, Vaccine, 22, 2776-2782. 

Daunorabicin (DaunoXome, Gilead Sciences, Inc.) Doxorubicin (Doxil/Caelyx, Ortho Biotech ProductsLP/Sequus Pharmaceuticals) Amphotericin B (Ambisome/Abelcet, Fujisawa Healthcare, Wyeth Pharmaceuticals) Doxorubicin (Myocet/Evacet, Sopherion/ Liposome Company) Hepatitis A virus envelope proteins (Epaxal, Berna Biotech) Influenza virus (Inflexal V, Berna Biotech) Verteporfin (Visudyne, Novartis Ophthalmics) Kaposi s sarcoma Kaposi s sarcoma Fungal infections in immunocompromised patients Metastatic breast cancer Hepatitis A Influenza Age-related macular degeneration... 

Japanese encephalitis virus envelop protein yes measles virus H and F protein yes... 

Fig. 1. Illustration of two morphologies of enveloped viruses (not drawn to scale). (A) The surface proteins of influenzavirus project like spikes or cylinders from the virus envelope. (B) The surface proteins of flaviviruses lie flat against the virus envelope.

Fig. 6. Repacking of the influenza HA2 hydrophobic core. Left. A ribbon trace of HA2 residues 38 to 127, including the helices that make up the core of the stalk in the native HA structure (see Fig. 3). Middle A hypothetical structure obtained by fusing the base of the coiled coil from the native HA structure with the top of the extended coiled coil from the low pH-converted HA structure. This panel helps distinguish the two major components of the HA conformational change on low pH treatment the existence of such an intermediate structure has not been shovm experimentally for influenza and may exist only transiently if at all. This extended structure, known as a prehairpin intermediate, has been detected indirectly in other virus envelope proteins (reviewed in Chan and Kim, 1998). Right Residues 38 to 127 from low pH-converted HA2 (Bullough et al, 1994). Hydrophobic residues that stabilize the jackknifed structure are indicated in one protomer as gray space-filling atoms. The amino (N) and carboxy (C) termini of a protomer within each trimer structure are indicated.

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