Cytotoxicity of Bacterial Metabolic Products, including Listeriolysin O, on Leukocyte Targets

Table 3

Survival of PBMC cells of healthy person treated with different concentrations of L. monocytogenes strain supernatants.

Strain		Supernatant concentrations
		10%	20%	30%	40%	50%
1044	Median	100,0%	99,0%	98,0%	98,0%	98,0%
	P25–P75	96,5–100,5	89,0–100,5	90,5–99,5	89,0–98,5	86,5–98,0
10403S	Median	78,0%	47,0%	8,0%	8,0%	7,0%
	P25– P75	57,0– 84,0	29,0–55,5	5,5–11,5	6,5–10,0	4,5–7,0
MAC	Median	14,0%	2,0%	2,0%	1,0%	0,0%
	P25–P75	9,5–33,5	2,0–20,0	1,0–4,0	0,5–3,0	0,0–3,0
1189	Median	76,0%	65,0%	49,0%	18,0%	11,0%
	P25–P75	54,5–82,0	35,0–79,0	25,0–61,6	9,5–20,0	6,0–15,5
1190	Median	78,0%	69,0%	30,0%	17,0%	21,0%
	P25–P75	60,5–83,5	47,5–74,0	17,0–38,0	9,5–21,5	10,5–23,5

The supernatant of the 1044 mutant strain was used as a control sample not containing LLO. The percent given is that of living cells in the PI assay with different final supernatant concentrations of 1–50%, following incubation for 30 min at 22^°C (median values, P25–P75, 𝑛=4). The incubation medium contained 4% inactivated NCS. The activity of the MAC supernatant was significantly higher (𝑃<0.05) than those of the 10403S, 1189, and 1190 strains.