Binding of CXCL8/IL-8 to Mycobacterium tuberculosis Modulates the Innate Immune Response

Figure 4

Effect of direct association of IL-8 with M. tb molecules on the ability of THP-1 cells to phagocytose and kill M. tb. (a) Phagocytosis of M. tb only (M. tb), or M. tb bound to IL-8 (M. tb/IL-8) presented as a phagocytosis index/increase fold over M. tb only. Image of THP-1 cell phagocyting M. tb conjugated with FITC photographed under fluorescent microscope. (b) Phagocytosis and killing of M. tb only (M. tb), or M. tb associated with IL-8 (M. tb/IL-8) calculated after 30 min and 3 h of infection using colony forming units (CFU) method and presented as a CFU/fold over M. tb only. (c) Killing index calculated for M. tb cytokine-free (M. tb) and M. tb associated with IL-8 (M. tb/IL-8) according to the formula ([CFU at 30 min − CFU at 3 h] × 100/CFU at 30 min).

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