Antiretroviral therapy used to treat HIV have different drug classes that deal with the various stages of the HIV life cycle. The stages of the HIV life cycle are outlined below.

• Binding – The first stage, where the CD4 cell latches onto the cell on the surface
• Fusion – The second stage, where the whole HIV viral envelope fuses with the cell, allowing entry in
• Reverse Transcriptase – In the third stage, the virus releases an HIV enzyme that permits it to convert the genetic makeup of the virus, converting HIV RNA to HIV DNA. Then, the virus enters the cell’s nucleus
• Integration – The fourth stage, where the HIV enzyme, integrase, integrates its DNA into the DNA of the infected CD4 cells
• Replication – In the fifth stage, the virus forms HIV proteins in long chains that HIV uses to replicate and spread throughout the body to other CD4 cells
• Assembly – In the sixth stage, the production of new HIV RNA and proteins occur from the infected CD4 cell and go to the surface of the cell to gather as noninfectious, immature HIV
• Budding – The final, seventh stage, where HIV releases from the infected CD4 cell that produced it, and it releases protease to break up the long chains of proteins that form the immature HIV. As the separation occurs, they combine and mature to become infectious HIV