Production of TNF-alpha and IL-6 in Macrophages by Mycobacterial Protein Antigens

ABSTRACT

BACKGROUND: Mycobacterial antigens released as PIM, LM, LAM, lipoproteins and other cellular factors may contribute to macrophage and dendritic cell activation through pattern recognition receptors such as TLRs. In this study, we assessed cytokine production and ERK activation with stimulation of several major mycobacterial antigens. METHODS: Purified mycobacterial antigens (10, 22, 30, 38kappaDa) and recombinant antigens (6, 16, 19, 38kappaDa, Ag85A antigen) were studied. The production of cytokines (TNF-alpha, IL-12, IL-6) was measured by ELISA. The ERK activation was detected by western blotting. The expression of TLR2 or TLR4 was measured by flow cytometry. RESULTS: Among purified antigens only 30kappaDa antigen induced production of IL-6 or TNF-alpha in THP-1 macrophage cells. When THP-1 macrophage cells were treated with 30kappaDa antigen, phosphorylation of ERK was detected. ERK activation also occurred in TLR2 transfectant HEK293 cells with 30kappaDa antigen stimulation. CONCLUSION: 30kappaDa antigen is one of the major mycobacterial antigens inducing cytokine production and MAP kinases phosphorylation in macrophages.