3.6 | mAb-EspB-B7 specificity towards EPEC EspB
homologs
To assess the specificity of mAb-EspB-B7 toward EspB homologs in other
bacterial pathogens, bacterial cultures grown under T3SS-inducing
conditions were centrifuged, and supernatants and pellets were analyzed
by SDS-PAGE and western blotting using mAb-EspB-B7. The following WT
bacteria and T3SS-mutant strains were cultured: EPEC; enterohemorrhagicE. coli (EHEC), which causes a more severe disease than EPEC in
humans; C. rodentium , an EPEC-related mouse pathogen; andSalmonella enterica serovar Typhimurium, which utilizes two T3SSs
for virulence. The strongest signal was observed for the WT EPEC
supernatant; a significant, but less strong, signal was also detected
for C. rodentium , and an even less strong signal, for EHEC
(Figure 6A). However, no signals were detected in the supernatants ofSalmonella or any of the T3SS mutant strains. Sequence alignment
of EPEC and C. rodentium EspB proteins revealed high conservation
between the proteins and full conservation of the mAb-EspB-B7 epitope
sequence. Sequence alignment between EPEC and EHEC EspB proteins
revealed 80% similarity at the mAb-EspB-B7 epitope region (Figure 6B).