(Last updated 9/22/2015; last reviewed 9/22/2015)
Once a person is infected with HIV, the virus begins to attack and destroy the CD4 cells of the immune system. CD4 cells are a type of white blood cell that play a major role in protecting the body from infection. HIV uses the machinery of the CD4 cells to multiply (make copies of itself) and spread throughout the body. This process, which includes seven steps or stages, is called the HIV life cycle.
Antiretroviral therapy (ART) is the use of HIV medicines to treat HIV infection. HIV medicines protect the immune system by blocking HIV at different stages of the HIV life cycle.
HIV medicines are grouped into different drug classes according to how they fight HIV. Each class of drugs attacks HIV at a different stage of the HIV life cycle.
People on ART take a combination of HIV medicines from at least two different HIV drug classes every day. Because HIV medicines in different drug classes block HIV at different stages of the HIV life cycle, ART is very effective at preventing HIV from multiplying. Having less HIV in the body protects the immune system and prevents HIV from advancing to AIDS. ART also reduces the risk of HIV drug resistance.
ART can’t cure HIV, but HIV medicines help people with HIV live longer, healthier lives. HIV medicines also reduce the risk of sexual transmission of HIV.
The seven stages of the HIV life cycle are: 1) binding, 2) fusion, 3) reverse transcription, 4) integration, 5) replication, 6) assembly, and 7) budding. To understand each stage in the HIV life cycle, it helps to first imagine what HIV looks like.
Now follow each stage in the HIV life cycle, as HIV attacks a CD4 cell and uses the machinery of the cell to multiply.