Mycobacterium tuberculosis Multidrug-Resistant Strain M Induces Low IL-8 and Inhibits TNF-α Secretion by Bronchial Epithelial Cells Altering Neutrophil Effector Functions

Figure 2

Characterization of conditioned media from infected Calu-6. Conditioned media (CM) from 18 h cultured uninfected (control-CM) or H37Rv- or M-infected Calu-6 cells (H37Rv-CM and M-CM) were tested for (a) TGF-β, TNF-α, GM-CSF, and IL-8 by ELISA. Results are expressed as pg/ml and mean ± SEM. Statistical differences: for H37Rv-CM or M-CM versus control-CM, for M-CM versus H37Rv-CM. (b) LDH release by employing a kinetic UV assay. Triplicates for each condition were performed. Percentage of LDH release was calculated as described in Materials and Methods. Results expressed as mean ± SEM (). (c) Ability to attract resting PMN by employing a PMN chemotaxis assay and fMLP (10⁻⁷ M) as positive control. Migrated PMN were counted by light microscopy. Five random fields per condition (each condition by triplicated) were analyzed, and results were expressed as number of migrated PMN/field (mean and SEM). Statistical differences: for H37Rv-CM or M-CM versus control-CM.

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