HIV-1_BaL p24⁺ DCs mature and up-regulate CD86 after CD40L stimulation. Immature DCs were exposed to 1 × or 10 × HIV-1_BaL for 72 hours with or without CD40L stimulation during the final 24 hours. The expression of CD86 and intracellular p24 on CD1a⁺ DCs was determined by flow cytometry. Gates were set on large CD1a⁺ CD3^- cells. (A) Average CD86 expression ± SEM of 5 donors in p24^- DCs (▪) and p24⁺ DCs (□). Significant differences were assessed by an unpaired t test and are indicated by ^* (P < .05) and ^** (P < 0.01), respectively. (B) The CD86 versus p24 expression on unstimulated (top row) and CD40L stimulated (bottom row) control DCs from 1 representative donor of 3 after 72 hours of 10 × HIV-1_BaL exposure with or without CD40L stimulation during the final 24 hours.