Fig. 1

MTB-Specific TNF-α-, IFN-γ- and dual IFN-γ/TNF-α-secreting T cells detected with FluoroSpot assay. Images of a well captured under different filters are presented as an example. (A) Red spots represent total TNF-α specific T cells. (B) Green spots represent total IFN-γ specific T cells. (C) Overlay of (A) and (B). Yellow spots from superposition of red and green fluorescence represent T cells dually secreting IFN-γ and TNF-α after stimulation. Single cytokine (TNF-α or IFN-γ) secreting T cell frequencies equals the frequencies of dual secreting T cells subtracted from total T cells