FIG 1.

Frequent IFN-γ⁺ CD107⁺ CD8⁺ T cells specific to the HSV-1 UL44_400–408, UL9_196–204, and UL25_572–580 epitopes detected HSV-seropositive ASYMP HLA-A*0201⁺ individuals. PBMCs (∼10 × 10⁶) derived from HSV-seropositive (SeroPos) asymptomatic (ASYMP) and symptomatic (SYMP) individuals and from HSV-seronegative (SeroNeg) individuals were stimulated in vitro with 10 μM (each) immunodominant CD8⁺ T cell peptide epitopes (UL44_400–408, UL9_196–204, and UL25_572–580) (Table 1). (A) Representative FACS contour plots of UL44_400–408, UL9_196–204, and UL25_572–580 tetramer-specific CD8⁺ T cells detected in one HSV-seropositive ASYMP individual (top row), one HSV-seropositive SYMP individual (middle row), and one SeroNeg individual (bottom row). (B) Average frequencies of CD8⁺ T cells specific to the UL44_400–408, UL9_196–204, and UL25_572–580 epitopes detected in 10 HLA-A*0201⁺ ASYMP (closed circles), eight HLA-A*0201⁺ SYMP (open circles), and five HSV-seronegative (open squares) individuals. The nominal P values indicate statistical significance detected between ASYMP and SYMP individuals and between SeroPos ASYMP and SeroNeg individuals. A general linear model was used, and we compared the least-squares means by the Dunnett procedure for multiple comparisons. (C) Frequencies of proliferative CFSE^low CD8⁺ T cells, detected by a CFSE dilution method following in vitro stimulation with the UL44_400–408, UL9_196–204, and UL25_572–580 peptides. The top row shows contour plots of individual tetramer-specific CFSE^low CD8⁺ T cells in HLA-A*0201⁺ ASYMP individuals. The bottom row shows contour plots of tetramer-specific CFSE^low CD8⁺ T cells in HLA-A*0201⁻ ASYMP individuals. (D) Frequencies of HSV-1 UL44_400–408, UL9_196–204, and UL25_572–580 epitope-specific IFN-γ⁺ CD8⁺ T cells (top two rows) and CD107⁺ CD8⁺ T cells (bottom two rows) in HLA-A*0201⁺ and HLA-A*0201⁻ ASYMP individuals. The results are representative of two independent experiments.