Siliciano continued his training in immunology with Ellis Reinherz at Harvard University, investigating the response of CD4-positive T-cells to antigens.
In 1995, Siliciano's lab provided the first demonstration that latently infected cells are present in persons living with HIV.
Working together with his wife Janet Siliciano, he demonstrated that the latent reservoir decays so slowly that lifetime persistence of HIV is guaranteed even in people taking effective combinations of antiretroviral drugs.
Because the latent reservoir is the major barrier to curing HIV infection, it is subject of an intense international research effort.
Some people experience side effects when taking these medications, and if treatment is interrupted, HIV can emerge from this latent reservoir and begin replicating and spreading again.