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Review of HIV
To understand HIV drug resistance it is important to have a general knowledge of HIV and how it works. The human immunodeficiency virus (HIV) is a retrovirus that infects CD4 T cells. CD4 T cells are important cells in the immune system that signal the body to fight off infection and disease.
Once HIV enters the body, it attaches itself to CD4 T cells and begins the replication process. Replication is how HIV makes copies of itself and multiplies. In order to replicate, an HIV particle must get its genetic blueprint, known as RNA, inside the host CD4 T cell. By doing this, the virus can reprogram the CD4 T cell and turn it into a virus-making machine.
Once inside the host cell, the virus must translate the RNA instructions into DNA so that the cell can understand them. To do this, HIV uses an enzyme known as reverse transcriptase. This enzyme takes the single strand of viral RNA and turns it into a double strand of DNA, which the cell can read. A class of drugs known as reverse transcriptase inhibitors is designed to stop this process.
Once the new viral RNA strand moves out of the host DNA, the strand is "cut" into smaller parts, or subunits. The protease enzyme makes this process possible; however, drugs called protease inhibitors can interrupt the enzyme's activity.
The subunits come together to form new HIV particles, which move out of the cell to infect other CD4 T cells. This process repeats itself continuously, and after repeated assaults by viral particles, the CD4 host cells die. As the number of CD4 cells decreases, the immune system can lose its ability to fight life-threatening infections.
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