Fig 2.

IL-1β production in response to P. aeruginosa is independent of phagocytosis and increases with induction of bacterium-BMDC contact. (A) BMDC from C57BL/6 mice were infected with PA14 (WT) at an MOI of 50 in the presence of either 10 μM cytochalasin D or a vehicle control. Culture supernatants were collected 3 h postinfection and analyzed by ELISA for IL-1β production. (B and C) BMDC from C57BL/6 mice were infected with the indicated WT or isogenic mutant strain of P. aeruginosa at an MOI of 5. Bacteria were either centrifuged at 500 × g for 5 min to force contact with BMDC (denoted by “s”) or not centrifuged as controls (unmarked). Culture supernatants were collected 3 h postinfection and analyzed by ELISA for IL-1β production. The ratio of IL-1β production after centrifugation to IL-1β production without centrifugation (B) and the raw values of elicited IL-1β (C) are shown. Data are representative of two independent experiments (A, n = 5; C, n = 6) and expressed as means ± standard deviations.