FIG. 3.

(A) RT-PCR Southern blotting for cytokine production in IFN-γ- and LPS-activated human macrophages. The cDNAs of human macrophages infected for 3 days with M. tuberculosis H37Rv and the clinical strain CMT97 were assayed with cytokine-specific primers. The housekeeping gene was β2 microblobulin (bottom line). The cytokines induced by CMT97 in the activated cells are only IL-1β and TNF-α, while laboratory strain H37Rv infection induces the production of all the cytokines analyzed. (B) Graphic representation of the modulation of CFU, bacterial gene expression, and IFN-γ production relative to H37Rv- and CMT97-infected macrophages, On the y axis are reported arbitrary units, ranging from 1 (assigned to the minimum value obtained) to 10 (assigned to the maximum value), independent of the absolute values of each group of observations. In particular, for CFU the values represent the bacterial colonies obtained from infected-cell lysates; for gene expression they reflect the number of M. tuberculosis-expressed genes out of the total number analyzed; for IFN-γ expression we considered the minimum and maximum optical density of the RT-PCR bands obtained.