Clinical Isolates of Mycobacterium tuberculosis Differ in Their Ability to Induce Respiratory Burst and Apoptosis in Neutrophils as a Possible Mechanism of Immune Escape

Figure 5

ROS production induced by Mtb strains in PMN. (a) PMNs treated with DHR were incubated with Mtb strains and MFI of 123rodhamine was measured by flow cytometry. Different Mtb : PMN ratios were tested (1 : 2, 5 : 1, 20 : 1, and 50 : 1) and a representative experiment out of three is shown. (b) ROS production induced at low Mtb : PMN ratio (1 : 2); results are expressed as media ± SEM (𝑛=20), statistical differences: control versus LAM, H37Rv, and H: ^∗𝑃<0.001. (c) ROS production induced at 50 : 1 Mtb : PMN ratio; results are expressed as media ± SEM (𝑛=20), statistical differences: control versus LAM ^∗∗∗𝑃<0.001; H37Rv and H ^∗∗𝑃<0.01; M ^∗𝑃<0.05. (d) ROS production was induced with gamma-irradiated or heat-killed (Ø) Mtb strains at 1 : 2 Mtb : PMN ratio. Statistical differences: control (—) versus LAM ^∗𝑃<0.001; LAM versus LAMØ ^#𝑃<0.01. A representative experiment is embedded. In all cases PMNs were washed, and 10,000 events were collected in a flow cytometer as described in Section 2.

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