A higher depth in IKKε exon 20 than in exon 19 was detected in the mock infection group, while a lower depth in IKKε exon 20 than in exon 19 was observed at 4 and 8 h.p.i., suggesting that IKKε isoform switching took place at 4 and 8 h.p.i. Here, IKBKE is linked to infection.