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Virus

About: Virus is a research topic. Over the lifetime, 136914 publications have been published within this topic receiving 5209107 citations. The topic is also known as: infectious agent & viruses.


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Journal ArticleDOI
20 Jun 1986-Science
TL;DR: The repeated isolation from a given individual of only highly related viruses raises the possibility that some type of interference mechanism may prevent simultaneous infection by more than one major genotypic form of the virus.
Abstract: In a study of genetic variation in the AIDS virus, HTLV-III/LAV, sequential virus isolates from persistently infected individuals were examined by Southern blot genomic analysis, molecular cloning, and nucleotide sequencing. Four to six virus isolates were obtained from each of three individuals over a 1-year or 2-year period. Changes were detected throughout the viral genomes and consisted of isolated and clustered nucleotide point mutations as well as short deletions or insertions. Results from genomic restriction mapping and nucleotide sequence comparisons indicated that viruses isolated sequentially had evolved in parallel from a common progenitor virus. The rate of evolution of HTLV-III/LAV was estimated to be at least 10(-3) nucleotide substitutions per site per year for the env gene and 10(-4) for the gag gene, values a millionfold greater than for most DNA genomes. Despite this relatively rapid rate of sequence divergence, virus isolates from any one patient were all much more related to each other than to viruses from other individuals. In view of the substantial heterogeneity among most independent HTLV-III/LAV isolates, the repeated isolation from a given individual of only highly related viruses raises the possibility that some type of interference mechanism may prevent simultaneous infection by more than one major genotypic form of the virus.

570 citations

Journal ArticleDOI
18 Apr 2013-Nature
TL;DR: It is shown that HAV released from cells is cloaked in host-derived membranes, thereby protecting the virion from antibody-mediated neutralization, and blurs the classic distinction between ‘enveloped’ and ‘non-envelope’ viruses and has broad implications for mechanisms of viral egress from infected cells as well as host immune responses.
Abstract: Animal viruses are broadly categorized structurally by the presence or absence of an envelope composed of a lipid-bilayer membrane, attributes that profoundly affect stability, transmission and immune recognition. Among those lacking an envelope, the Picornaviridae are a large and diverse family of positive-strand RNA viruses that includes hepatitis A virus (HAV), an ancient human pathogen that remains a common cause of enterically transmitted hepatitis. HAV infects in a stealth-like manner and replicates efficiently in the liver. Virus-specific antibodies appear only after 3-4 weeks of infection, and typically herald its resolution. Although unexplained mechanistically, both anti-HAV antibody and inactivated whole-virus vaccines prevent disease when administered as late as 2 weeks after exposure, when virus replication is well established in the liver. Here we show that HAV released from cells is cloaked in host-derived membranes, thereby protecting the virion from antibody-mediated neutralization. These enveloped viruses ('eHAV') resemble exosomes, small vesicles that are increasingly recognized to be important in intercellular communications. They are fully infectious, sensitive to extraction with chloroform, and circulate in the blood of infected humans. Their biogenesis is dependent on host proteins associated with endosomal-sorting complexes required for transport (ESCRT), namely VPS4B and ALIX. Whereas the hijacking of membranes by HAV facilitates escape from neutralizing antibodies and probably promotes virus spread within the liver, anti-capsid antibodies restrict replication after infection with eHAV, suggesting a possible explanation for prophylaxis after exposure. Membrane hijacking by HAV blurs the classic distinction between 'enveloped' and 'non-enveloped' viruses and has broad implications for mechanisms of viral egress from infected cells as well as host immune responses.

569 citations

Journal ArticleDOI
TL;DR: Immunologic evidence was obtained to support the thesis that the etiologic agents of varicella and herpes zoster have been isolated and propagated in vitro.
Abstract: SummaryTissue culture preparations infected with agents originally derived from the eruptive lesions of cases of varicella and herpes zoster, as well as control preparations infected with the virus of herpes simplex, were studied by a modification of the fluorescent antibody technic. Employing the infected preparations as antigen, fixation of antibody from human sera derived from cases of varicella, herpes zoster or herpes simplex was detected by the use of a fluorescent antihuman gamma globulin conjugate. Antibody reacting with the varicella and herpes zoster antigens to an almost identical degree appeared during convalescence in serum specimens derived either from cases of varicella or from cases of herpes zoster. Antibody reacting with herpes simplex virus was demonstrated uniformly only in a group of sera derived from cases of recurrent herpes simplex. Immunologic evidence was thus obtained to support the thesis that the etiologic agents of varicella and herpes zoster have been isolated and propagated...

568 citations

Journal ArticleDOI
06 Dec 1979-Nature
TL;DR: A composite DNA sequence of regions of hepatitis B virus, determined from a series of recombinant plasmids, reveals the genes for the surface antigen and the core antigen of the virus.
Abstract: A composite DNA sequence of regions of hepatitis B virus, determined from a series of recombinant plasmids, reveals the genes for the surface antigen and the core antigen of the virus. The sequence of the core antigen shows it to be a DNA binding protein. The core antigen gene is expressed in Escherichia coli and when injected into rabbits the bacterial product induces antibodies which react with core antigen isolated from human sources.

566 citations


Network Information
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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20242
20234,275
20228,706
20213,455
20203,848
20193,309