重组腺病毒理论-11-16.ppt

acellular organisms whose genomes consist of nucleic acid (RNA or DNA but not both), and which obligately replicate inside host cells using host metabolic machinery and ribosomes to form a pool of components which assemble into particles called VIRIONS （病毒体）, which are released and infect other cells. VIRION（病毒体） the complete infectious unit of virus particle structurally mature, extracellular virus particles Viral core viral nucleic acid genome control the viral heredity and variation Genome either DNA or RNA double-stranded or single stranded linear or circular segmented or non-segmented open reading frame (ORF) overlapping gene Viral Capsid The protein shell, or coat, that encloses the nucleic acid genome. Functions: a. Protect the viral nucleic acid b. Participate in the viral infection c. Share the antigenicity Nucleocapsid The core of a virus particle consisting of the genome plus a complex of proteins. Envelope A lipid-containing membrane that surrounds some viral particles. It is acquired during viral maturation by a budding process through a cellular membrane. enveloped virus and naked virus Spike or Peplomere 刺突/包膜子粒 Functions of envelope Antigenicity some viruses possess neuraminidase Infectivity Resistance Virion REPLICATION OF VIRUSES Replicative cycle self-replication As obligate intracellular parasites, virus must enter and replicate in living cells in order to “reproduce” themselves. This “growth cycle” involves specific attachment of virus, penetration and uncoating, nucleic acid transcription, protein synthesis, maturation and assembly of the virions and their subsequent release from the cell by budding or lysis. Attachment/Adsorption Virus attaches to the cell surface via specific receptors. Cells without the appropriate receptors are not susceptible to the virus. Penetration (Virus enters the cell) Enveloped viruses the virus envelope fuses with the plasma membrane to facilitate entry Non-enveloped viruses