RARα modulators intrinsically regulate IL-5+ Th2 cell proliferation. In vitro differentiated Th2 cells were CTV labeled and activated with the noted stimuli in the presence and absence of ATRA or Ro41. After 8d cells were restimulated with PMA and ionomycin and ICCS was performed. (A) Representative flow plot showing total IL-5 vs. CTV (top panel), as well as CTV staining of IL-5+ Th2 (middle panel), and IL-5- Th2 (bottom panel) subpopulations. Combined results from 5 Th2 cultures showing CTVlow percentages of (B) total, (C) IL-5+ Th2, and (D) IL-5- Th2 subpopulations. Data are presented with means (bar) and p values were generated via paired Student’s t test.