Surface expression of CD95L in untreated or FK-treated Nef transfectants cultured in RPMI + 0.1% FCS for 24 hours. Unshadowed histograms represent cells treated with anti-CD95L + GAM-FITC, and shadowed histograms are negative controls (cells treated with anti-p66 of HCMV + GAM-FITC). X-axis, relative CD95L expression detected by fluorescence intensity (log scale); y-axis, relative number of cells. A representative of four separate experiments is shown. The MFI of the four experiments (AU) was 11 ± 4 (JH6.2), 63 ± 11 (JBru.2), 175 ± 46 (JBru.2 + FK), and 248 ± 70 (JBru.3).