Both asymptomatic and symptomatic individuals show functional CMV-specific CD8⁺ T cells.

The percentage CMV-specific CD8⁺ T cells enumerated by tetramer binding, percentage CMV-specific IFN-γ–producing CD8⁺ T cells enumerated by intracellular cytokine staining on specific peptide stimulation and specific lysis (E/T ratios, 1:1, 1:2, and 1:4) in one asymptomatic patient (patient 2, panels A,C) and one symptomatic patient (patient 6, panels B,D).