Cytotoxicity of AA100, the ΔrtxA mutant (ΔrtxA), and ΔrtxA transformed with pJDC20, pJDC35, and pJDC40 for human monocytic cell line THP-1. Data points and error bars represent the means of triplicate samples from a representative experiment and their standard deviations, respectively. All experiments were performed at least three times.