HIV

HUMAN IMMUNODEFICIENCY VIRUS

wHAT IS it aLL ABOUT?

 

iT IS A LENTIVIRUS

 

A GENUS OF VIRUSES OF THE RETROVIRIDAE FAMILY

Causes aids

acquired immunodeficiency syndrome

a disease of the human immune system that allows life-threatening opportunistic infections and cancers to thrive

Without treatment, average survival time after infection is 9 to 11 years

methods of transmission

Blood

Semen

vaginal fluid

pre-ejaculate

breast milk

structure

shape: roughly shperical

Diameter: 120nm

from outermost to innermost of the virion

1. viral envelope

COMPRISE OF a lipid bilayer

with protein gp160 embedded on it

2. MATRIX

 

COMPRISE OF PROTEIN P17

3. CAPSID

Comprise of protein p24

4. two copies of single-stranded rna genome

Proteins encoded by the HIV genome
Class Gene name Primary protein products Processed protein products
Viral structural proteins gag Gag polyprotein MA, CA, SP1, NC, SP2, P6
pol Pol polyprotein RT, RNase H, IN, PR
env gp160 gp120, gp41
Essential regulatory elements tat Tat
rev Rev
Accessory regulatory proteins nef Nef
vpr Vpr
vif Vif
vpu Vpu
 

essential replication enzymes

protease

integrase

reverse transcriptase


replication cycle

1. ATTACHMENT

hiv approaches target cell

GP160 SPIKE BINDS WITH HOST CELL RECEPTOR CD4 AND CO-RECEPTOR CCR5 OR CXCR4

2. membrane fusion

gp41 collapse into a hairpin, bringing together the virus and cell membrane for fusion to take place

3. replication and transcription

Reverse transcriptase reverse transcripts the single-stranded rna genome to form a double-stranded viral dna

The DOUBLE-STRANDED VIRAL DNA is transported into the cell nucleus

integrase integrates the viral dna into the host cell's genome

provirus dna is transcribed into messenger rna (mrna)

4. assembly

mrna is transported to the cytoplasm

mrna is translated into regulatory proteins

Protease cleaves longer proteins into shorter core proteins

GAG POLYPROTEINS ARE CLEAVED INTO ACTUAL MATRIX, CAPSID AND NUCLEOCAPSID PROTEINS BY PROTEASE

gp160 goes through the endoplasmic reticulum and golgi apparatus where it is cleaved by furin into gp41 and gp120

the various structural components then assemble to produce a mature hiv virion

mature hiv virion leave the host and are able to infect other cells


Designed by Thomas Splettstoesser (www.scistyle.com)

treatment

use of antiretroviral drugs

1. nucleoside reverse transcriptase inhibitors

interfere with the action of reverse transcriptase, which is needed for viral replication

2. Non-Nucleoside Reverse Transcriptase Inhibitors

also stop HIV from replicating within cells by inhibiting the reverse transcriptase protein

3. protease inhibitors

inhibit protease, another protein involved in the HIV replication process

4. Fusion or Entry Inhibitors

prevent HIV from binding to or entering human immune cells

5. Integrase Inhibitors

interfere with the integrase enzyme, which HIV needs to insert its genetic material into human cells

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