Figure 5: Caspase and GrB may be involved in different types of Th cell apoptotic mechanisms that are induced by different S. japonicum antigens. (a) Splenocytes from SWA-immunized mice were restimulated in vitro with SWA or PBS in the presence or absence of the GrB inhibitor Z-AAD-CMK. (b) Splenocytes from SEA immunized mice were restimulated in vitro with SEA or PBS in the presence or absence of the caspase inhibitor Z-VAD-FMK. After 36 hours, restimulated T cells in (a) and (b) were purified by MACS and stained with anti-IFN--PE or anti-IL-4-PE mAbs. Apoptotic cells were labeled with an Apo-Direct TUNEL assay kit and then detected by FACS. The percentage of apoptotic Th1 or Th2 cells among the purified T cells was derived from the number of IFN- or IL- cells and gated on the TUNEL positive population. Data are expressed as the meanSD of 18 mice from three independent experiments. ; . Left panels: One representative experiment of flow cytometric analysis with the average percentage of Th or apoptotic cells shown in the FACS data. Right panels: The statistical analysis of 18 mice from three independent experiments.