IL1B and infection: Although transcription of the precursor pro-IL1β gene is under the control of NF-κB transcription factors, pro-IL18 mRNA is constitutively expressed and has different regulatory controls.43 The fact that in our studies IL18 was also upregulated by VVL15∆N1L infection suggests that the N1L protein may additionally regulate inflammasome signaling by a previously undescribed mechanism of action.