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. 2014 Sep 8;143(2):258–268. doi: 10.1111/imm.12306

Figure 7.

Figure 7

Delineation of Toll-like receptor (TLR2) signalling by heat-killed Mycobacterium indicus pranii (MIP-K), live Mycobacterium indicus pranii (MIP-L) and bacillus Calmette–Guérin (BCG). HEK293 cells expressing TLR2/2, TLR2/1 or TLR2/6 (a, b and c, respectively) were stimulated with MIP-K, MIP-L and BCG in native or sonicated form at a multiplicity of infection of 50. Culture supernatants were collected after 48 hr and analysed for interleukin-8 (IL-8) by ELISA. Higher levels of IL-8 production from 293tlr2/2, 293tlr2/1 and 293tlr2/6 cells were observed in response to native and sonicated MIP-L. Maximum level of IL-8 was produced by 293tlr2/1 cells. Native MIP-K led to moderate levels of IL-8 from 293tlr2/2, 293tlr2/1 and 293tlr2/6 cells. Native BCG did not lead to IL-8 production from either of 293tlr2/2, 293tlr2/1 and 293tlr2/6 cells, indicating that TLR2 ligands are not well exposed in native BCG. Substantial levels of IL-8 were produced by 293tlr2/2, 293tlr2/1 and 293tlr2/6 cells in response to sonicated BCG. SPL-Streptococcus pneumoniae lysate (TLR2/2 ligand, MOS = 50), Pam-Pam3CSK4 (TLR2/1 ligand, 0·2 μg/ml), FSL1 (TLR2/6 ligand, 1 μg/ml) were used as positive controls. Data shown are mean ± SEM of three independent experiments. *P < 0·05, **P < 0·01, ***P < 0·001 and ns, not significant.