FIG. 3.

Vβ2-specific expansion of T cells. Expansion of Vβ2⁺ T cells on SPEC-stimulated human PBL was analyzed by two-color flow cytometry. PBL (10⁶/ml) from three healthy volunteers were incubated with PBS, wild-type SPEC, or mutant SPEC Y15I (final toxin concentration, 100 pg/ml) for 6 days, double stained with a biotin-conjugated anti-OKT3 MAb and a fluorescein isothiocyanate-conjugated anti-Vβ2 MAb, followed by phycoerythrin-avidin, and analyzed by a FACScan. The flow cytometric profiles of three individual samples of PBL are shown.