ATRA does not affect caspase-3 activation in CD3 stimulated Th2 cells. Th1 and Th2 cell lines were generated in vitro then activated with anti-CD3 antibody in presence of ATRA or DMSO vehicle control. Cultures were harvested 4d later and stained for activated caspase-3. 2xTh2, 3xTh2, etc. represent 2, and 3 serial 7d cycles of Th2 differentiation. Above, flow cytometry plots are shown for all cell lines. Below, combined results from all cultures noting the percentage of viable (Live/Dead negative) activated caspase-3+ cells (mean +/- SEM). No statistical differences were observed by paired Student’s t test.