Fig. 1.

Cytotoxicity of normal woodchuck peripheral blood mononuclear cells (PBMC) towards Fas-competent and Fas-deficient target cells. PBMC from 11 healthy, woodchuck hepatitis virus (WHV)-negative woodchucks were incubated with ⁵¹Cr-labelled Fas expressing P815 cells (solid line) or Fas-deficient K562 cells (dashed line) at indicated E:T ratios. Data from evaluations with 30 and 19 individual PBMC samples were used to determine P815 and K562 cell killing, respectively. The results are expressed as percentage specific lysis ± s.e.m.