Ex vivo phenotypic analysis of CPS- and FPT-specific T cells. Panel A: PBMC from HCMV-infected healthy individual were co-stained with pMHC-pentamers and antibodies specific for CD27, CD57 and CD62L. Data presented here is a summary of 3 different experiments. Panel B: To determine any functional differences between CPS and FPT-specific T cells, these effector cells were exposed to MRC-5 cells expressing HLA B*3508 and co-infected with HCMV at an MOI of 0.5:1. 2 different responder to stimulator ratios (80:1 and 20:1) were used in these assays. Following incubation, these cells were co-stained with pMHC pentamer, anti-IFN-γ and anti-CD107a as outlined in the Material and Methods section. This data are representative of 3 different experiments.