The effectiveness of α-GalCer depends on both iNOS and CD95. Bone marrow was collected from BALB/c (panels A and D) or from C57BL/6 wild-type controls and mutant iNOS-deficient mice (panel B) or from BALB/c lpr mutant mice, lacking CD95 (panel C). Cultures were established for 7 days in the presence of IL-5 (1 ng·mL−1), alone or together with α-GalCer (10−8 M). Panel (A), where indicated (+), aminoguanidine (AmGua; 10−4 M); panel (D), as indicated, indomethacin (Indo, 10−7 M), aspirin (Asp, 10−8 M) or LTD4 (10−7 M). **P ≤ 0.05, significantly different as indicated; n = 3 for all panels.