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. 2015 Mar 20;11(3):e1004749. doi: 10.1371/journal.ppat.1004749

Fig 1. S. sonnei ΔgalU LPS mutant possesses immunogenic and antigenic Phase I material on the surface.

Fig 1

(A) Silver staining and immunoblot analysis of phenol-water extracts from S. sonnei WT, S. sonnei ΔgalU and S. sonnei -pSS bacteria. Samples were run on 12% Bis-Tris SDS-PAGE, blotted, and membranes were incubated with S. sonnei Phase I monovalent antiserum (anti-Ss Phase I) at a dilution of 1:1000. (B) Flow cytometry analysis of surface staining of live S. sonnei WT and S. sonnei -pSS. Bacteria were stained with sera raised against GMMA from hyperblebbing S. sonnei with WT LPS (anti-Ss GMMA), S. sonnei -pSS with rough LPS (anti-Ss -pSS GMMA), or S. sonnei ΔgalU with deep rough LPS (anti-Ss ΔgalU GMMA). Gray profiles: staining with preimmune sera; black profiles: staining with GMMA antisera (1:1000). Representative results of three experiments are shown. (C) Competitive surface staining of S. sonnei WT live bacteria with sera raised against GMMA from hyperblebbing S. sonnei ΔgalU strain (anti-Ss ΔgalU GMMA). Gray profiles: staining with preimmune sera; black solid profiles: staining with anti-Ss ΔgalU GMMA; black dashed profile: staining with anti-Ss ΔgalU GMMA absorbed with S. sonnei WT (Ss WT) phenol-water extract; black dotted profile: staining with anti-Ss ΔgalU GMMA absorbed with S. sonnei -pSS (Ss -pSS) phenol-water extract. Sera dilution was 1:10000. (D) Surface staining of formalin-fixed S. sonnei WT, S. sonnei ΔgalU and S. sonnei -pSS with S. sonnei Phase I monovalent antiserum (anti-Ss Phase I). Gray profiles: staining with S. flexneri type II monovalent antiserum; black profiles: staining with anti-Ss Phase I. Sera dilution was 1:5000.