Figure 6. Effect of HCMV immunoevasins on epitope-specific T cell cytotoxicity.

MRC-5 fibroblasts (HLA-A*0201, C*0702) were preincubated in medium with (A) or without (B) IFN-γ for 72 hours before infection at moi = 5 with AD169 (CMV-wt) or its derivatives CMV-Δall (ΔUS2/3/6/11), CMV-US11 (ΔUS2/3/6) or CMV-US2 (ΔUS3/6/11). Cytotoxicity was determined at 48 hours post infection in a 3.5-hour calcein release assay using an effector∶target ratio of 4. Fibroblasts that were not infected (n.i.) or peptide-loaded (n.i. +peptide) were negative and positive controls, respectively. Data are shown as mean+SD of three to four replicates.