PMAIP1 and infection: Four of these genes also showed >1.5 fold up-regulation in H5N1- compared with H1N1-infected cells at 3 h post-infection: TNF, IFN-induced protein with tetratricopeptide repeats 2 (IFIT2), macrophage inflammatory protein 1-β (CCL4L1), and phorbol-12-myristate-13-acetate-induced protein 1 (PMAIP1).