Submitted by: Submitted by azura90
Views: 152
Words: 979
Pages: 4
Category: Science and Technology
Date Submitted: 12/07/2012 08:17 AM
Human Retrovirus
• HTLV1
• HTLV2
• HIV-1, HIV-2
o HIV-2 less virulent
• Human foamy virus
• Human placental virus
• Human genome virus
HIV
• Retrovirus
• Enveloped
• + sense
• 2 ssRNA, 3 enzymes in genome
• Classified into types, groups, subtypes based on genetic similarities
o M (major) group
o O (outlier) group
o N & P (new) group
• Highly variable virus – mutates very readily
o High error rate of reverse transcriptase
o High replication rate of virus in vivo
• Destroy cells of immune system → immunosuppression
• Infect cells with CD4+ receptor (T-helper, macrophage, DC)
↓
Destruction through:
o Direct viral killing of infected cells
o ↑ rate of apoptosis of infected cells
o CD8+ T-cells mediated apoptosis
Susceptible Cells
• T-helper cells
• B lymphocytes
• Macrophages
• Dendritic cells
• Neurons
HIV Receptors
• CD4 on T-helper
• CXCR-4 chemokine receptor (used by T-cell tropic HIV strain)
• CCR-5 chemokine receptor (used by macrophage-tropic HIV strain)
CCR-5 Co-receptor Function
• Attachment
o gp120 bind to CD4 T-cell → conformational change
• Binding to second receptor
o Gp120 bind to CKR5
• Fusion
o Fusion peptide from gp41 exposed
o Viral and cell membrane fuse
Structure
[pic]
• Structural proteins
o gag – structural capsid proteins
o env – envelope glycoproteins
• Catalytic protein (yg biji2 kt tgh pic)
o pol – reverse transcriptase & viral integrase
• Regulatory proteins – tat, rev
• Accessory proteins – vpu, vif, vpr, nef
Production of DNA
• 2 ssRNA → dsDNA
• DNA is longer due to terminal repeats
• Reverse transcription...