Project Summary/Abstract HIV has proven remarkably adept and avoiding nearly all attempts at a cure, with one and possibly two individuals to date having been successfully cured. More and better ideas are needed to develop novel cure strategies. The creation of these strategies relies on a far better understanding of the host and viral factors that dictate reservoir size, location, and evasion of immune responses and therapeutics. Here, we will assess the importance of the viral Nef protein in establishment and maintenance of the SIV reservoir in SIV infected macaques. In Aim 1, we will use a cell culture model of SIV latency to assess whether variants of Nef are better or worse at protecting latently infected cells from antiviral immune responses. In Aim 2, we will infect macaques with Nef mutant viruses or wild type, place the animals on suppressive cART therapy, and comprehensively assess the reservoir, in terms of size, location, viral expression and viral sequence evolution. These studies will be important in assessing whether novel therapeutics that target the Nef protein (either via vaccination or pharmacological) might be fruitful in eradication strategies moving forward.