Figure 4A shows that infection of BM-DC with H37Ra or H37Ra::rpsL induced no stimulation of the hybridoma as judged by IL-2 production, while H37Ra::phoP or H37Rv triggered high amounts of IL-2 production in this very sensitive and specific test. All strains behaved comparably towards the Ag85A:241–260 control, emphasizing the specificity of the observed phenomenon for ESAT-6 (Figure 4B). This evidence concerns the gene IL2 and infection.