Pre-treatment with IFN-γ increases HuPrP82-146-induced caspase-3 activity. Levels of caspase-3 activity in cortical neurons pre-treated with control medium (○), or with 100 ng/ml IFN-γ (●) prior to the addition of varying concentrations of HuPrP82-146. Also shown is the caspase-3 activity from neurons pre-treated with control medium (□), or with 100 ng/ml IFN-γ (■) and incubated with varying concentrations of HuPrP82-146scrambled. Values shown are the mean percentage fluorescence units from quadruplicate experiments repeated twice (n = 8), ± SD. ** = Caspase 3 activity significantly greater than untreated neurons incubated with HuPrP82-146 (p < 0.05).