HIV replication and Pathogenesis

Question 1

T/F: HIV is zoonotic?

Answer 1

True, first came from chimps

*3 independent introductions of SIV into humans in early 1900s

Question 2

HIV routes of transmission?

Answer 2

unprotected sex
sharing needles
vertical transmission (mom to baby)
blood transfusion

Question 3

Can mosquitos give you HIV?

Answer 3

NO

Question 4

Who is at highest risk for HIV infection in the US?

Answer 4

MSM

Question 5

HIV exposure and infection

Answer 5

1) few virions breach epithelium
1. 5) there is a short window to attempt prevention with drugs/ vaccines
2) virions infect tissue macrophages, dendritic cells
3) infected cells produce virions and migrate to lymph nodes
4) virions spread from regional lymph nodes to gut lymphoid tissue (GALT)

Question 6

Are men or women more likely to be infected with HIV?

Answer 6

women

Question 7

HIV is an ___ virus. It is _____ to cause disease. diploid or haploid?

Answer 7

RNA virus
Lentivirus= slow to cause disease
ssRNA + strand
diploid

Question 8

What is the difference between early HIV infection and late infection in terms of tropism?

Answer 8

early: HIV binds to CCR5 receptor on CD4 T cells, and also to macrophages
late: HIV evolves to preferentially bind CXCR4 receptor on CD4 T cells

Question 9

HIV lifecycle

Answer 9

1- attachment and fusion
2- uncoating in cytoplasm
3- reverse transcription 
4- migration of genome to nucleus (via integrase)
5- integration into host chromosome (end of phase 1)
6- mRNA and genome synth
7- mRNA export
8- viral protein synth. 
9- genomic RNA export
10- spliced mRNA synth
11- viral membrane protein synth
12- protein maturation
13- protein accumulation at plasma membrane
14- virion assembly at PM 
15- budding 
16- virion maturation

Question 10

HIV attachment

Answer 10

HIV Env= TM (transmembrane gp41) and SU (gp120)
SU binds CD4 and CHEMOKINE receptors–> conformation change in TM
TM fusion peptide inserts into target cell membrane

Question 11

What makes a cell resistant to HIV infection?

Answer 11

no chemokine receptor

Question 12

Two key points about reverse transcription?

Answer 12

tRNA bound to ssRNA = primer

templates switch during replication

Question 13

HIV genome intergration into host chromosome is ____

Answer 13

permanent–> creates a reservoir of latent virus in the body