Frequently asked question: Does your own body defend itself against an HIV infection?
Your body tries to combat the HIV infection itself. Your immune system can recognize the HIV cells and wants to attack and destroy them. However, because the virus replicates itself as fast as possible, small mistakes are made and the copy always looks slightly different. That is called mutation (alteration in genetic material). The immune cells do not recognize the virus particle anymore and do not destroy it right away. This means that the virus particle can continue replicating itself undisturbed.
Your body tries to do something about the HIV infection, as it is aware that foreign invaders are active. Your immune system actually has exploratory cells that continuously scan your body. CD4 cells that are infected with HIV are recognized in this way and your immune cells will attack and destroy them as well as possible. However, because the virus replicates itself as fast as possible, mistakes are made and the copy always looks slightly different. That is called mutation. Your immune system therefore does not recognize the virus particle right away and it is not immediately eliminated. The mutated virus particle has some time and continues to replicate itself at a rapid pace, causing more cells to become infected.