Infection of A549 cells with HPIV3 resulted in induction of endogenous RIGI expression (RT-PCR was performed using the following primers: RIGI forward, 5'-GCATATTGACTGGACGTGGCA, RIGI reverse, 5'-CAGTCATGGCTGCAGTTCTGTC) during relatively early infection time frame (8 h-12 h post-infection) (Fig. 3A). Here, RIGI is linked to infection.