FIG 4.

The immune-stimulatory capacity of strain 381 is not appreciably diminished in isogenic mutant strains bearing deletions in PGN_1320, PGN_1318, and PGN_1317 coding sequences. (A) HEK cells expressing TLR2 were stimulated with wild-type strains 33277 and 381 and the indicated isogenic 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 wild-type strains 33277 and 381 and the indicated isogenic 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 three independent experiments. Asterisks indicate statistical significance as determined by Student’s unpaired t test (*, P < 0.01; **, P < 0.001; ***, P < 0.0001). ns, not statistically significant.