HIV

Question 1

origin of the HIV epidemic

Answer 1

began with zoonotic ifnections with simian immunodeficiency cviruses from African primates
HIV-1 was transmitted from apes
HIV-2 was transmitted from sooty mangabey monkeys

Question 2

groups of HIV-1

Answer 2

HIV-1: four groups
M,N,O = transmitted from chimpanzees
P = transmitted from gorilla

N,O,P restricted to west Africa
M cause of global HIV pandemic

Question 3

Group M

Answer 3

cause of global HIV pandemic
started about 100 years ago
nine serotypes
A - D, F - H, J and K

C predominates in western Europe, America and Australia

Question 4

HIV-2

Answer 4

largely confined to west Africa
causes similar illness to HIV-1
immunodefiency progresses more slowly
less transmissible

Question 5

major causes non-AIDS related deaths

Answer 5

defined as deaths of people under antiretroviral therapy, but not caused directly by AIDS

cancer
cardiovascular disease (50% increased risk of myocardial infarctions)
liver disease (co-infection with Hepatitis B and C)
tuberculosis
secondary infections in general

Question 6

general facts about HIV infection biology

Answer 6

main target cells are CD4+ T-cells

use CD4 as primary cell surface receptor
chemokine co-receptors CCR5 and CXCR4 as secondary receptors

other cells which get infected: resting CD4+ T-cells, monocytes, makrophages, dendritic cells
CD4-independent infection in: astrocytes and renal epithelial cells -> neurocognitive disorders and neprhopathy as developed disorders

Question 7

infection cycle

Answer 7

1) binding to CD4
2) binding to coreceptor (CCR5/ CXCR4)
3) fusion and release of viral components into cytoplasm of host cell
4) reverse transcription of viral RNA genome into DNA
5) transport of viral DNA genome into nucleus
6) integration of viral DNA genome into host genome (can persist as latent infection for years)
7) transcription of viral DNA to viral mRNA and transport back into the cytosol
8) translation of viral proteins
9) assembly of new virions
10) budds out of the cell and a new infectios virion can infect neighbouring cells

Question 8

HIV structure

Answer 8

enveloped virus
protein capsid
RNA genome
contains viral reverse transcriptase

Question 9

AIDS

Answer 9

aquired immuno deficiency syndrome
caused by HIV infection
progressive depletion of CD4+ T-cells

Question 10

antiretroviral therapy

Answer 10

were developed in late 1990’s
transformed HIV from a fatal disease to a chronic managable disease
combination therapy out of several HIV medications

standard regimen:
two nucleoside reverse transcriptase inhibitors +
non nucleoside reverse transcriptase inhibitor/ protease inhibitor/ integrase inhibitor

under successful regiment patient’s plasma viral load decreases below detection limit (takes around 3 months)