Envelope cholesterol withdrawal impairs HIV-induced IFN-α production and IDO activity. IFN-α (A) and IFN-β (B) were quantified by ELISA in the supernatants of PBLs from healthy donors (n = 19) cultured with HIV or HIV treated with different concentrations of βCD (20, 80, or 120mM) or medium alone (CTRL). (C) The concentrations of kynurenine (KYN) and tryptophan (TRP) were measured by HPLC (n = 25); the ratio between KYN and TRP is shown; horizontal dotted line indicates the sensitivity threshold of the assay. (D) IFN-α in supernatants from PBLs cultured in the presence of HIV, βCD80-HIV, or βCD120-HIV normalized according to viral RNA concentrations (n = 3). In all graphs, horizontal bars represent median values; in panels A-C, boxes indicate the interquartile range and vertical lines extend to 90th and 10th percentiles. In panel D, vertical lines indicate interquartile range. *P values that remained significant after Hochberg correction for multiple comparisons.