In our study, 3D was found to suppress the apoptosis in A549 cells induced by A/Weiss/43 H1N1 in a dose-dependent manner at 24 h post-infection and repressed the expression of cleaved caspase-3, caspase-7, caspase-9, and cleaved PARP (the main cleavage target of caspase-3 in vivo). This evidence concerns the gene CASP9 and infection.