HIV restriction in quiescent CD4⁺ T cells.

The restriction of the Human Immunodeficiency Virus (HIV) infection in quiescent CD4⁺ T cells has been an area of active investigation. Early studies have suggested that this T cell subset is refractory to infection by the virus. Subsequently it was demonstrated that quiescent cells could be infected at low levels; nevertheless these observations supported the earlier assertions of debilitating defects in the viral life cycle. This phenomenon raised hopes that identification of the block in quiescent cells could lead to the development of new therapies against HIV. As limiting levels of raw cellular factors such as nucleotides did not account for the block to infection, a number of groups pursued the identification of cellular proteins whose presence or absence may impact the permissiveness of quiescent T cells to HIV infection. A series of studies in the past few years have identified a number of host factors implicated in the block to infection. In this review, we will present the progress made, other avenues of investigation and the potential impact these studies have in the development of more effective therapies against HIV.