IL1B and infection: A. actinomycetemcomitans cytolethal distending toxin (AaCdt) was shown to be involved in NLRP3 activation in THP-1 monocytes and release of mature IL-1β [30], but other bacterial factors may be also associated with this response to A. actinomycetemcomitans, since infection of human monocytes with leukotoxin- and Cdt-deficient strains still resulted in upregulation of NLRP3, IL-1β and IL-18 expression [31].