Assessment of ASC Oligomerization by Flow Cytometry

Inflammasomes are multiprotein complexes that critically control different aspects of innate and adaptive immunity. Upon activation, inflammasome proteins oligomerize forming scaffolds to nucleate the apoptosis-associated speck-like protein containing a CARD (ASC) in filaments that will finally result in large ASC oligomers that are commonly named as ASC specks. In this chapter, we present a method to monitor NLRP3 or pyrin inflammasome activation in human monocytes upon extracellular ATP or Clostridium difficile toxin B treatment, respectively, by detecting intracellular oligomers of ASC by flow cytometry. This method could be used to evaluate the degree of inflammasome activation in blood samples from patients suffering from different chronic inflammatory diseases.