FIG 9.
Influence of heat inactivation on the immune-stimulatory activity of strains 33277 and 381 and the isogenic fimB mutant strains. (A) HEK cells expressing TLR2 were stimulated with live (L) or heat-inactivated (HK) wild-type strains 33277 and 381 and the indicated isogenic fimB mutant strains (105 bacteria). Fold change in NF-κB activation from bacterial stimulations is shown relative to the unstimulated control. (B) Differentiated THP-1 cells were stimulated with live (L) or heat-inactivated (HK) wild-type strains 33277 and 381 and the indicated isogenic fimB mutant strains (105 bacteria). Fold change in IL-1β production from bacterial stimulations is shown relative to the unstimulated control. Data are presented as means ± SD from triplicate sample determinations and are representative of two independent experiments. Asterisks indicate statistical significance as determined by Student’s unpaired t test (*, P < 0.05; **, P < 0.001; ***, P < 0.0001). ns, not significant.