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
| 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
HIV
By Arnold Tan
