Host-derived enzymes and other proteins can modulate bacterial quorum sensing by altering autoinducer levels through processes including autoinducer modification89 (part a), autoinducer degradation92 (part b) or autoinducer sequestration96,97 (part c). These processes, because they inactivate autoinducers (parts a, b) or make autoinducers unavailable (part c), induce the LCD quorum-sensing state, causing bacteria to enact individual behaviours.