Chitotriosidase activity in the supernatant and cell-lysate of macrophages after incubation with cystine crystals. (A) Chitotriosidase activity in the supernatant of macrophages incubated with different concentrations of cystine crystals (experiment 1). (B) Chitotriosidase activity in the cell-lysate of macrophages incubated with 100 ug/cm2 cystine crystals (experiment 2). Results were represented as averages and standard deviations of 2 independent experiments in triplicate for experiment 1 and in duplicate for experiment 2. Enzyme activities for both experiments were expressed as nmol enzyme activity/mg pellet protein/h. *represents P < 0.05 with the zero level crystal concentration.