IL1B and infection: To assess a role forintracellular K+ efflux in caspase-1 activation and IL-1βrelease during infection with Y. pestis, BMDMs were infectedwith Yp-YopJKIM or Yp-YopJC172A, and then incubated incell culture media supplemented with 30 mM KCl, 30 mM NaCl or no supplement.Cell culture supernatants were collected at 8 hr and 24 hr time points andanalyzed for the presence of IL-1β and TNF-α by ELISA.