TLR2-IN-C29 is a toll/IL-1 receptor resistance (TIR) domain BB loop-targeting, selective toll-like receptor 2 (TLR2) antagonist th at inhibits both human TLR2/1 and TLR2/6-mediated signaling (IC50 = 37.6/19.7 μM against 50 ng/mL Pam3CSK/Pam2CSK-induced reporter signal, respectively, using HEK293T TLR2/6 or TLR2/1 transfectants), while blocking only murine TLR2/1-, but not murine TLR2/6-, mediated signaling (1h 25-50 μM C29 treatment prior to 50 ng P3C/mL or 100 ng P2C/mL for 1h in murine macrophages), nor signaling induced by other TLR agonists and TNF-α.