Figure 1

Analysis of in vitro and in vivo expression of recombinant Salmonella- EGFP strains. (A) and (B) Representative fluorescence microscopy images of EGFP antigen expression in six ‘single-recombinant’ Salmonella strains: HP, LP, CP, HO, CO and E (A) and in five ‘double-recombinant’ Salmonella strains: CP + HP, CP + LP, CP + HO, CP + E and E + LP (B). The SL7207 parent strain was used as a control. B.F. = bright-field images; MERGE = composite of bright-field and fluorescent images. Scale bar represents 5 μm. (C) Western blot analysis of EGFP expression in the CO strain. Expression of EGFP protein (theoretical mass ca. 39 kDa) was detected using a GFP rabbit polyclonal IgG. The SL7207 strain was used as a negative control. (D) Western blot analysis of EGFP expression in the Caco-2 human colon carcinoma cell line delivered by E strain. Expression of EGFP protein (theoretical mass ca. 26 kDa) was detected at 12, 20 and 30 hours after infection using a GFP mouse monoclonal IgG. The SL7207 strain was used as a negative control. The GAPDH detection was performed as the internal control. (E) Western blot analysis of EGFP expression in mice intestine mucosa delivered by E strain. EGFP detection was carried out on day 1, 3 and 7 after inoculation. The SL7207 strain was performed identically as a negative control. The GAPDH was detected as the internal control.