پاورپوینت AIDS and Lentiviruses (زبان انگلیسی)

دانلود پاورپوینت AIDS and Lentiviruses (زبان انگلیسی)

• Introduction
• Human immunodeficiency virus (HIV) derived from primate lentiviruses etiologic agents of AIDS
• The illness was first described in 1981 and was isolated by the end of 1983
• once infected, individuals remain infected for life
• Within a decade, if left untreated, the vast majority of HIV-infected individuals develop fatal opportunistic infections as a result of HIV-induced deficiencies in the immune system.
• AIDS the most important public health problems worldwide at the start of the 21st century.

Virion: Spherical & cylindric core

Genome: Single-stranded RNA, linear, positive-sense, diploid

Proteins: Envelope glycoprotein undergoes antigenic variation; reverse transcriptase enzyme contained inside virions; protease required for production of infectious virus

Envelope: Particles bud from plasma membrane

Replication: Reverse transcriptase makes DNA copy from genomic RNA; provirus DNA is template for viral RNA. Genetic variability is common.

Outstanding characteristics:

nononcogenic

may be cytocidal

Infect cells of the immune system

Cause slowly progressive, chronic diseases

• 4 genes required for a replicating retrovirus gag, pro, pol, and env
• Up to 6 additional genes regulate viral expression and are important in disease pathogenesis in vivo.
•  

• Heterogeneous populations of viral genomes are found in an infected individual reflects high rates of viral replication and the high error rate of the viral reverse transcriptase.
• The regions of greatest divergence env gene
• The SU (gp120) binding domains virus attachment to the CD4 molecule and coreceptors     determines lymphocyte and macrophage tropisms
•  
• The TM (gp41) transmembrane domain that anchors the glycoprotein in the viral envelope and a fusion domain that facilitates viral penetration into target cells.

• Classification
• HIV is a retrovirus
• Family Retroviridae
• Genus Lentivirus
• There are two distinct types of human AIDS viruses: HIV-1 and HIV-2.
• Sequence divergence between HIV-1 and HIV-2 exceeds 50%.

• The primate lentiviruses fall into 6 major phylogenetic lineages:
• SIV from sooty mangabeys = HIV-2
• SIV from chimpanzee = HIV-1

 

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