Integrase is an enzyme that is used by HIV to integrate its genetic material, or DNA, into the DNA of a human host cell. After an HIV particle attaches to and penetrates a human cell, it releases its genetic code, or RNA, into the cell. It uses an enzyme called reverse transcriptase to convert the HIV RNA into HIV DNA, which then enters the human cell's nucleus. This is where the viral DNA uses integrase, through a multistep process, to become incorporated into the cell's DNA. Once the integration is complete, the virus can replicate and infect new cells.

Because the integration process is crucial for viral replication, it is considered an attractive target for new antiretroviral therapies. Integrase inhibitors, which are a new class of investigational drugs, may inhibit the activity of integrase during the strand transfer, or joining, of the HIV DNA and the cellular DNA. Blocking this process may inhibit the ability of the virus to replicate and infect new cells.