Fig. 2.

Ratio of kynurenine to tryptophan concentrations (µmol/mmol) to estimate activity of indoleamine (2,3)-dioxygenase in unstimulated peripheral blood mononuclear cells (US) and in cells stimulated with 10 µg/ml phytohaemagglutinin (PHA), 10 µg/ml concanavalin A (Con A) and 0·5 µg/ml pokeweed mitogen (PWM) treated with increasing doses of aspirin. Kyn/trp is shown as x-fold change from baseline in unstimulated cells; columns show mean values ± s.e.m. of three experiments run in duplicate, total number of data included in each column = 6; *P < 0·01 compared to cells stimulated by the corresponding mitogen but without aspirin treatment; #P < 0·01 compared to untreated cells).