18- HERPES_SIMPLEX_VIRUS_and_VARICELLA_ZOSTER_VIRUS___Web_Syllabus___OXMAN__1_June_2011_052711083314

18- HERPES_SIMPLEX_VIRUS_and_VARICELLA_ZOSTER_VIRUS___Web_Syllabus___OXMAN__1_June_2011_052711083314

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Michael N. Oxman, MD Herpes Simplex Viruses and Varicella-Zoster Virus Microbiology June 1, 2011 1 Herpes Simplex Virus and Varicella-Zoster Virus Michael N. Oxman, MD in collaboration with Bridget A. Quinn Alpha Herpesviruses: Herpes Simplex Virus (HSV) and Varicella-Zoster Virus (VZV) I. Key Features of the Human Herpesviridae (HSV-1, HSV-2, VZV, CMV, EBV, HHV-6,-7,-8) Herpesviruses are large and complex viruses. Herpesviruses encode many enzymes, including enzymes involved with nucleic acid synthesis and nucleic acid metabolism. This is important because these viral enzymes are potential targets for antiviral drugs like acyclovir. Members of Herpesviridae all have a similar virion structure: They are enveloped viruses . (Remember, enveloped viruses acquire their lipid membrane from the host cell.) They have icosahedral capsids . Between the envelope and the capsid is an amorphous protein-filled region called the tegument . They have linear double stranded DNA genomes . Their genomes consist of UL and US regions bounded by inverted repeats (IR) . o However, the exact arrangement of the genome differs in different Herpesviruses. Virus replication and assembly occurs in the nucleus of the infected cell, although late steps in virion assembly may take place in the cytoplasm. There are no common Human Herpesvirus Family antigens . All members of the Herpesviridae can establish latency in their natural host. Members of the Herpesvirus Family are subdivided into subfamilies, primarily on the basis of their biologic properties and/or their genome organization and DNA sequence homology. Alpha ( α ) Herpesviruses (HSV-1, HSV-2, VZV) have a relatively broad host range; a short replication cycle; produce CPE in cell cultures and in vivo that is characterized by eosinophilic intranuclear inclusion bodies, multinucleated giant cells, and subsequent cell death; and establish latent infections, primarily in sensory neurons. Beta ( β ) Herpesviruses (CMV, Roseolaviruses [HHV-6, HHV-7]) have a relatively restricted host range, a long replication cycle, produce slowly progressive infections in cell culture, and produce CPE characterized by cell enlargement (cytomegalia). Persistent or latent infections are readily established in secretory glands, in reticuloendothelial cells, in the kidney and in other tissues. Gamma ( γ ) Herpesviruses (EBV, HHV-8) have a very restricted host range. They replicate in lymphoblastoid cells in vitro and tend to be specific for either T- or B-lymphocytes, in which they may either establish a latent or a productive lytic infection. Latency is frequently demonstrated in lymphoid tissue. EM of a Herpesvirus II. Key Features of the Alpha ( α ) Herpesviruses (HSV and VZV) The double stranded DNA genome of the alpha herpesviruses have the following arrangements: o HSV : TR-U L -IRIR-U S -TR o VZV : --U L --IR-U S -IR U S U S U L HSV U L VZV IR IR Alpha Herpesvirus Genomes TR L IR L IR S TR S
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This note was uploaded on 09/14/2011 for the course PHARM mb taught by Professor Staff during the Spring '11 term at UCSD.

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18- HERPES_SIMPLEX_VIRUS_and_VARICELLA_ZOSTER_VIRUS___Web_Syllabus___OXMAN__1_June_2011_052711083314

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