Eliminating HIV-1 from infected patients is the ultimate therapeutic achievement. Highly active antiretroviral therapy (HAART) in 1996 improved the quality and the expectancy of life for individuals infected with human immunodeficiency virus (HIV)-1. HAART achieves remarkable results in suppressing HIV-1 replication to levels so low that it cannot be detected in blood. However, HAART is not the magic bullet: it is expensive, it is toxic, and it requires strict compliance. More importantly, HAART does not cure HIV-1. A major reason for that failure is that HIV-1 has developed ways of infecting some cells without killing them: it stays within them for long periods of time, hiding from HAART and from the immune system. These cells are called viral reservoirs, and researchers have uncovered that many different types of reservoir exist. What further complicates the issue is that HIV-1 has developed ways to achieve persistent infection that are different for each one of these reservoirs: in some reservoirs HIV-1 lies dormant (a state known as latency), while in others replicates actively. Researchers at the Institute of Human Virology are involved in studying the nature of these viral reservoirs: how they are established, how they work, and ultimately how they can be eliminated. Drs. Fabio Romerio and Maria Iglesias-Ussel are focusing their efforts on CD4+ T cells, which represent the largest viral reservoir in the body. They found a way to produce these cells in the laboratory, and are attempting to identify unique biomarkers on these that can be used as therapeutic targets. Drs. Suzanne Gartner, Senthilkumar Natesan and Yiling Liu have discovered a previously unknown cell, with certain macrophage characteristics, that is highly susceptible to HIV-1 infection and capable of producing the virus for long periods of time. Their work also suggests a critical link between persistent HIV-1 infection in macrophages and T cells.