FIG 2.

Rapid secretion of IL-1β from THP-1 cells induced by V. cholerae El Tor is due to secreted hemolysin and dependent on NLRP3. (A) Western blotting for actin indicating the presence or absence of MARTX toxin-dependent actin laddering in THP-1 cells after treatment with isogenic V. cholerae strains derived from the El Tor wild-type strain P27459, including the ΔctxAB mutant P4 and the ΔctxABΔhapA mutant KFV70 with additional deletions in rtxA or hlyA as indicated. (B) The strains indicated were streaked onto blood agar showing zones of clearing around strains that secrete hemolysin. IL-1β secretion (C, D, and F) or percent lysis as measured by LDH release (E) from THP-1 (gray bars), ASCdef THP-1 (white bars), or NLRP3def THP-1 cells (striped bars) treated with the V. cholerae strains indicated at an MOI of 25 for 3 h. Data are presented as the mean ± the standard deviation of triplicate samples. *, P < 0.05.