Cell-surface phenotype of individual subsets of CD8⁺and CD8β⁺ human large pre-T cells. Large CD3⁻ DP pre-T cells shown in Fig 1 were stained with directly labeled MoAb against the indicated cell-surface molecules. FCA was performed on electronically gated CD8⁺β⁻ (shaded areas) or CD8⁺β⁺ (unshaded areas, bold line) cells. Large CD3^low pT⁺ pre-T cells, shown to be homogeneously CD8⁺β⁺ (see Fig1), were included in the study for comparison (unshaded areas, thin line). Background values (vertical lines) were determined with isotype-matched irrelevant MoAb. A representative analysis out of three independent experiments is shown.