Figure 1.

Effector CD8 T cells to viral antigen versus self-antigen. Naive HA-specific CD8 T cells were adoptively transferred into non-transgenic B10.D2, C3-HA^hi or B10.D2 mice infected with rVV-HA (rVV-HA). After 4 days, lymphocytes from peripheral lymph nodes were harvested for subsequent analyses. (a) In vivo divisions of CFSE-labelled HA-specific T cells. Events were gated on CD8⁺ Thy-1.1⁺ T cells. Arrows indicate cells with at least three divisions which were gated for sorting described in Fig. 6. (b) Expansion of HA-specific T cells. Cells were stained with either Thy-1.1 or K^dHA tetramer (K^dHA518-526) in combination with CD8. Percentage of double-positive cells is indicated. (c) Phenotypic characterization of HA-specific T cells. Cells were stained with activation marker CD44, CD62L or CD69. Events were gated on Thy-1.1⁺CD8⁺ T cells. (d) Functional analysis of HA-specific T cells. After in vitro re-stimulation with K^dHA peptide (2 µg/ml) for 6 hr, cells were stained with CD8, Thy-1.1 and IFN-γ intracellularly. The percentages of IFN-γ-producing clonotypic CD8 T cells are indicated. Events were gated on CD8⁺ T cells. (e) In vivo CTL assay. Mice were injected intravenously with an equal number mixture of K^dHA peptide-pulsed CFSE^hi-labelled (right peak) and control peptide-pulsed CFSE^lo-labelled (left peak) syngeneic targets. Six hours later, cells from peripheral lymph nodes were examined to detect and quantify CFSE-labelled cells. Percentage of specific lysis is indicated. Representative data of three independent experiments are shown.