HIV Virus Life Cycle and Drug Reaction

Binding and Fusion: HIV begins its life cycle
when it binds to a CD4 receptor and one of two
co-receptors on the surface of a CD4+
Tlymphocyte. The virus then fuses with the host
cell. After fusion, the virus releases RNA, its
genetic material, into the host cell.

Reverse Transcription: An HIV enzyme
called reverse transcriptase converts the singlestranded HIV RNA to double-stranded HIV DNA.

Integration: The newly formed HIV DNA
enters the host cell's nucleus, where an HIV
enzyme called integrase "hides" the HIV DNA
within the host cell's own DNA. The integrated
HIV DNA is called provirus. The provirus may
remain inactive for several years, producing few or
no new copies of HIV

Transcription: When the host cell receives a
signal to become active, the provirus uses a host
enzyme called RNA polymerase to create copies of
the HIV genomic material, as well as shorter
strands of RNA called messenger RNA (mRNA).
The mRNA is used as a blueprint to make long
chains of HIV proteins.

Assembly: An HIV enzyme called protease cuts
the long chains of HIV proteins into smaller
individual proteins. As the smaller HIV proteins
come together with copies of HIV's RNA genetic
material, a new virus particle is assembled.

Budding: The newly assembled virus pushes out
("buds") from the host cell. During budding, the new
virus steals part of the cell's outer envelope. This
envelope, which acts as a covering, is studded with
protein/sugar combinations called HIV
glycoproteins. These HIV glycoproteins are
necessary for the virus to bind CD4 and coreceptors. The new copies of HIV can now move
on to infect other cells.