Figure 3.

Sulfasalazine induces cell death in RBL5 T-lymphocytes in a dose- and time-dependent manner. (A) RBL5 cells were incubated with the indicated concentrations of sulfasalazine for 24 h, (B) or with 1.25 mM sulfasalazine for the indicated time periods. (C) 5ASA and sulfapyridine, the colonic metabolites of sulfasalazine, have no effect on T-cell viability. RBL5 T-lymphocytes were treated for 24 h either with medium (control) or increasing concentrations of 5ASA (white bars), sulfapyridine (SP) (black bars) or 5ASA plus sulfapyridine (hatched bars) as indicated. The percentage of dead cells was determined by FACS analysis on the basis of their characteristic forward/sideward light scatter changes as described (Carbonari et al., 1994). Data are obtained from three independent experiments done in duplicate (n=6) and are presented as mean and standard error of the mean (s.e.mean).