Figure 1. Alum-induced NLRP3 inflammasome activation.

Phagocytosed alum-containing lysosomes rupture and release their components to the cytosol by an unknown mechanism. The released contents and molecules generated during this process contribute to NLRP3/ASC/caspase-1 inflammasome activation, which in turn processes the proforms of IL-1 family members to active forms. Either IL-1 family member cytokines or the products from NLRP3 inflammasome activation may elicit various immunostimulatory effects in vivo. When and how potassium efflux and reactive oxygen species (ROS) play a role awaits further investigation. DC, dendritic cell; MSU, monosodium urate.