Figure 2.

Differential presentation of OVA-producing S. typhimurium PhoP^c by DCs and macrophages. (A and B) A representative experiment of at least two independent experiments performed in duplicate. The difference between the duplicates was <15%. Bone-marrow-derived DCs (A) or macrophages (B) were irradiated and incubated with S. typhimurium PhoP^c (hatched bars) or the virulent ATCC14028 (open bars) strain expressing OVA or GFP as a control, at a multiplicity of infection of 25. (C) The bone-marrow-derived DCs (squares) or macrophages (circles) were incubated with purified OVA at various concentrations. After 2.5 h, the cells were washed and incubated with gentamicin to kill extracellular bacteria. Naive CD4⁺ transgenic T cells specific for OVA_323–339 + IA^d were added. Proliferation of T cells was measured after 90 h by ³H-T incorporation. The mean ± SD of four values is plotted.