rHSP-D–enhanced apoptosis caused by the combination of IAV and E coli. The indicated concentrations of rHSP-D were preincubated with the combination of IAV (40 μg/mL) and E coli (250 μg/mL) for 30 minutes at 37°C, followed by addition of these samples to neutrophils and assessment of apoptosis at 8 and 24 hours as described in Fig 2. Samples of E coli or IAV alone or the combination of E coli and IAV (without rHSP-D) were run in parallel. Data are given as mean ± SEM of three separate experiments. (*)Indicates where rHSP-D significantly (P < .05) enhanced apoptosis as compared with the combination of E coli and IAV.