HIV Patient 0

Question 1

Major players

Answer 1

• SIVrcm(Mangabey) and SIVgsn(Guenon) make hybrid SIVcpz(chimpanzees) with both copies in cell
• ## Recombination of genes

Question 2

HIV 1

Answer 2

• Group M (major) -> many subtypes
• Group N (new)
• Group O (outlier)
• Group P

Question 3

HIV 1 Group M

Answer 3

• Major group
• 90% of HIV/AIDS cases
• 12 subtypes, A through L, CRF(circulating recombinant form)
• Clade B has anti tethering mechanism -> tethering mechanism works in every group but Group B

Question 4

HIV Group O

Answer 4

• Outlier group
• 2% of infections from cameroon
• Not seen outside west africa

Question 5

HIV Group N

Answer 5

• Refers to non M and non O groups
• Discovered in 1998 cameroon africa
• 10 group N infection reported

Question 6

Parts of HIV Virus Particle

Answer 6

• Reverse transcriptase
• Matrix (protein shell)
• Viral envelope(two layer lipid membrane)
• Capsid(protein shell)
• Glycoprotein - gp120: identifies and docks with host cell
• Glycoprotein -gp41: Completes docking and assist in fusion with host cell
• Viral RNA(two identical strands of genetic material)

Question 7

HIV Infection

Answer 7

• Crosses barrier -> dendritic cell act as host to macrophages bind to CD4 and CCR5-> produce infected CD4+ T cells (lamina propria) -> infected cells distribute via lymphatic vessels -> lymph nodes -> immune activation -> partial control and sustained HIV production

Question 8

Replication cycle of HIV

Answer 8

• Attaches to host via CD4 and CCR5 membrane proteins -> entry by membrane fusion -> virus enters cytosol and capsid uncoats -> dsDNA transcribed from ssRNA using reverse transcriptase -> dsDNA enter nuclear pores and integrates with host DNA -> transcription of mRNA and synthesis of viral proteins (gp41 and gp120) -> budding and release -> assembly and maturation

Question 9

Enchanced, positive ssRNA viruses with reverase transcriptase

Answer 9

• Reverse transcriptase transcribes dsDNA from ssRNA -> RNA dependent DNA polymerase
• Antigenic variants of HIV results from errors in genome during transcription
• RT use tRNA primer encoded by host cell
• dsDNA provirus finished in nucleus
• Viral integrase inserts provirus into human chromosome
• Integrated DNA passed to progeny cells during replication
• Provirus can remain dormant for years
• Macrophages/Dendritic cells and monocytes act as major resevoirs for HIV
• Only humans replicate HIV and HIV destroys immune system

Question 10

Vpu and Nef

Answer 10

• Vpu/Nef removes tetherin from cell surface -> allows HIV to infect
• In absence of Vpu/Nef, tetherin binds to HIV