Figure 2.

Gene transfer from S. typhimurium into mouse macrophages: Effective gene transfer from S. typhimurium into primary mouse macrophages was determined by using an EGFP-encoding plasmid. For this purpose, inflammatory exudate macrophages were cultured with S. typhimurium harboring the EGFP plasmid, and green fluorescence was analyzed after 36–48 h by UV microscopy at 488 nm (A and C). Arrowheads indicate location of macrophages. A macrophage cell line (RAW) transfected with the same EGFP plasmid by electroporation and green fluorescence was analyzed after 36 h (C and D). Identical microscopic fields were analyzed in the presence and absence of UV light (A corresponds to B; C corresponds to D). Photographs were taken at ×100 magnification.