Continuous treatment with recombinant Mycobacterium tuberculosis CFP-10-ESAT-6 protein activated human monocyte while deactivated LPS-stimulated macrophage

Influence of the recombinant culture filtered protein 10 (CFP-10) and early-secreted antigenic target 6 kDa protein (ESAT-6) (r-CFP-10-ESAT-6, rCE) of Mycobacterium tuberculosis (Mtb) on human monocyte and macrophage activation was investigated using human monocyte, monocyte like THP-1 cell line and monocyte derived macrophage (MDM). rCE solely enhanced TNF-α release from human monocytes and THP-1 cells in a dose- and time-dependent manner. rCE enhanced expression of CD80 and CD40, it also synergized with IFN-γ in induction of TNF-α production and HLA-DR expression. Pharmacological agents that selectively inhibit mitogen activated protein kinase activation markedly suppressed rCE-induced TNF- α release. However, continuous presence of rCE (>72 h) during monocyte to macrophage differentiation inhibited macrophage response to LPS stimulation. Collectively, these data suggest that rCE might have differential influence on monocyte and macrophage activation, which might be correlated with Mtb immune evasion.