FIGURE 5.

Effector lymphocytes from both CatC^−/− and CatCH^−/− mice retain sufficient GrB activity to induce DNA fragmentation in target cells. Membrane damage and DNA fragmentation induced in P815 target cells were assessed using ⁵¹Cr (A) or ¹²⁵I-DNA (B) release. CTLs from three separate primary MLR (at days 6 and 7) were used at the effector:target (E:T) ratio indicated. Aspase (GrB) and tryptase (GrA) activities were measured in substrate cleavage assays using specific peptide substrates, Boc-Ala-Ala-Asp-S-benzyl for GrB (C) or Boc-L-lysine-S-benzyl for GrA (D). Lysates were prepared from 7-day primary MLR. Each individual assay was performed using 30 μg protein, and the assays were repeated using lysates from multiple MLR as indicated. The total number of assays performed are indicated (n), and each assay was done in triplicate. The data were pooled, and the mean ± S.E. is shown.