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. 2002 Jan 22;99(3):1503–1508. doi: 10.1073/pnas.022649799

Figure 3.

Figure 3

M. tuberculosis induced repression of IL-12 protein production. (A) M. tuberculosis induced less IL-12 protein than E. coli and suppressed IL-12 production induced by E. coli. IL-12 p40 accumulation in supernatants of macrophages 12 h after exposure to either M. tuberculosis, E. coli, or both bacteria was measured by ELISA (R & D Systems). Additional experiments demonstrated that this response was reproducible and not donor dependent. TNF-α ELISA was performed on supernatants from the same cultures after 4 h (peak expression of this cytokine preceding the wash step). Values are means ± SD of replicate ELISA measurements. Neither IL-12 nor TNF-α was detected in macrophages treated with media alone.