Cells were analyzed for HLA-DR expression as previously described [56] . Briefly, cells were incubated with murine clone L243 [78] . Densitometric analysis was performed as previously described [80] and the percentage of total HIV-1 a CA p24 (183-H12-5C) [79] reactive bands was used as a measure of Gag processing [81] . Intracellular Gag staining 10 6 cells were permeabilized with IntraPrep Permeabilization Reagent (Beckman-Coulter, Fullerton, CA), following manufacturer's instructions. Gag was stained with FITC-conjugated FH190-1-1 (Beckman-Coulter) for approximately 15 m prior to analysis and data interpretation as performed above, with the exception of the percentage of Gag+ cells was determined after gating on HLA-DR+ cells.