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

Figure 3

Effect of direct association of IL-8 with M. tb molecules on the ability of neutrophils 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 neutrophil 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) 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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