Understanding how HIV infects the body is important when it comes to prevention and treatment, choosing to have safer sex and general HIV awareness. Learn more about the science behind the virus and the HIV life cycle.
The immune system and HIV
The HIV virus attacks white blood cells, which are called T-helper cells or CD4 cells. These are important when it comes to having a healthy immune system as they help us fight off diseases and infections.1
HIV cannot grow or reproduce on its own. Instead, it makes new copies of itself inside T-helper cells which damages the immune system and gradually weakens our natural defences. This process of T-helper cells multiplying is called the HIV life cycle.
How quickly the virus develops depends on how early you are diagnosed, your overall health and how well you take your treatment. It’s important to know that antiretroviral treatment will keep the immune system healthy if taken correctly and therefore prevent AIDS.2
The HIV life cycle
The life cycle of HIV goes through various different steps that can happen over many years. Antiretroviral treatment works by interrupting the cycle and protecting your immune system.3 There are different drugs offered depending on the particular stage of the HIV life cycle.
Understanding the HIV life cycle helps scientists to know how to attack the virus when it is weak and reduce the risk of drugs no longer working (drug resistance). This happens when drugs fail to prevent the virus from multiplying.4
Stages of the HIV life cycle
Binding and fusion
First, the HIV virus attaches itself to a T-helper cell. The spikes on the surface of the HIV particle stick to the cell and allow them to join together. The contents of the HIV particle are then released into the cell.
The type of drugs that can stop this part of the process are called Fusion or Entry Inhibitors.
Reverse transcription and integration
Once inside the cell, HIV changes its genetic material (called HIV RNA) into HIV DNA using an enzyme called reverse transcriptase. HIV DNA can then enter the DNA in the nucleus of the T-helper cell and control it.
The type of drugs that can stop this part of the process are called NRTIs, NNRTIs and Integrase Inhibitors.
Transcription and translation
The HIV DNA then makes long strands of messenger RNA proteins, and transports them towards the edge of the cell. This is then used for producing more HIV.
Assembly, budding and maturation
Copies of HIV genetic material are contained among the strands of messenger RNA. These form new HIV particles, which are then released from the T-helper cell. These are then ready to infect other cells and begin the process all over again.
The type of drugs that can stop this part of the process are called Protease Inhibitors.5
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