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. 2022 Jan 24;18(1):e1009718. doi: 10.1371/journal.ppat.1009718

Fig 7. Salmonella SPI-2 needle protein SsaG activates the NAIP/NLRC4 inflammasome in human macrophages.

Fig 7

(A) Primary hMDMs from four healthy human donors were infected with PBS (Mock), WT Listeria (WT Lm), Listeria expressing PrgJ (Lm + PrgJ), SsaI (Lm + SsaI), or SsaG (Lm + SsaG) for 16 hours at MOI = 5. Release of IL-18 into the supernatant was measured by ELISA. Each dot represents the mean of individual donors derived from triplicate wells. The grey bar represents the mean of all donors. (B) WT, NAIP-/-, and NLRC4-/- THP-1 monocyte-derived macrophages were primed with 100 ng/mL Pam3CSK4 for 16 hours. Cells were treated with PBS (Mock), WT Listeria (WT Lm), Listeria expressing PrgI (Lm + PrgI), or Listeria expressing SsaG (Lm + SsaG) for 6 hours at MOI = 20. Release of IL-1β into the supernatant was measured by ELISA. (C) WT, NAIP-/-, and NLRC4-/- THP-1 monocyte-derived macrophages were primed with 100 ng/mL Pam3CSK4 for 16 hours. Cells were then treated with PBS (Mock), PA alone, LFnSsaG, or PA+LFnSsaG (SsaGTox) for 6 hours. Release of IL-1β into the supernatant was measured by ELISA. ns–not significant, ***p < 0.001, ****p < 0.0001 paired t-test (A) or by Dunnett’s multiple comparisons test (B, C). Data shown are representative of at least three independent experiments.