(Last updated 10/25/2016; last reviewed 10/25/2016)
A latent HIV reservoir is a group of immune cells in the body that are infected with HIV but are not actively producing new HIV.
HIV attacks immune system cells in the body and uses the cells’ machinery to make copies of itself. After entering the body, HIV inserts its genetic blueprint into the DNA of an immune system cell, such as a CD4 cell. The infected cell starts producing HIV proteins, which act as the building blocks for new HIV. To find out more about how HIV attacks cells, read the AIDSinfo HIV Life Cycle fact sheet.
However, some HIV-infected cells shut down and go into a resting (or latent) state. While in this resting state, the infected cells don’t produce new HIV.
When HIV infects cells in this way, it can hide out inside these cells for years, forming a latent HIV reservoir. At any time, cells in the latent reservoir can become active again and start making more HIV.
Latent HIV reservoirs can be found throughout the body, including in the brain, lymph nodes, blood, and the digestive tract.
HIV medicines reduce the amount of HIV in the body (called the viral load) by preventing the virus from multiplying. Because the HIV-infected cells in a latent reservoir aren’t producing new copies of the virus, HIV medicines have no effect on them.
People with HIV must take a daily combination of HIV medicines (called an HIV regimen) to keep their viral loads low. If someone is not taking HIV medicines when the infected cells of the latent reservoir begin making HIV again, the viral load in the body will start to increase. That’s why it’s important to continue taking HIV medicines every day as prescribed, even when viral load levels are low.
Finding ways to target and destroy latent reservoirs is one of the major challenges facing HIV researchers. New studies are exploring different strategies for clearing out reservoirs, including: