Defect in CTL degranulation and cytotoxicity is more pronounced in souris mice compared with beige^J mice. On day 8 after LCMV infection, spleen cells were restimulated with gp33 and the CD107a surface expression of IFN-γ⁺CD8⁺ T cells was determined. (A) Representative FACS plots of restimulated CTLs and medium control. (B) Percentage of CD107a⁺IFN-γ⁺ CTLs after restimulation with gp33. (C) Cytotoxicity was measured in a ⁵¹Cr-release assay on gp33 peptide-loaded target cells (left panel, 10⁻⁶M; right panel, 10⁻¹⁰M) and on LCMV-infected target cells (middle panel). Results from one of 2 independent experiments with 3 to 5 mice per group are shown. ***P < .001.