Sepsis, a life-threatening condition caused by bacterial infection, is triggered by both Gram-negative and Gram-positive bacteria. This study investigates how Gram-positive bacteria, specifically through their components peptidoglycan (PGN) and lipoteichoic acid (LTA), activate host cells. The findings show that PGN and LTA, like lipopolysaccharide (LPS) from Gram-negative bacteria, activate the transcription factor NF-κB in host cells such as macrophages. This activation is mediated by Toll-like receptor 2 (TLR2), a member of the Toll-like receptor family. Unlike LPS, which requires serum for signaling, PGN and LTA can activate NF-κB in the absence of serum, indicating a distinct signaling pathway. The study demonstrates that TLR2 is essential for PGN and LTA-induced NF-κB activation, and that CD14, a glycosylphosphatidylinositol-anchored membrane protein, enhances this process. However, TLR2 alone is not sufficient for full activation, suggesting the involvement of additional co-receptors. The results indicate that TLR2 is not only a receptor for LPS but also for PGN and LTA from Gram-positive bacteria, expanding its role in immune responses. The study also highlights the importance of TLR2 in detecting and responding to Gram-positive bacterial components. While TLR4 is crucial for immune responses to Gram-negative bacteria, it may not be involved in responses to Gram-positive bacteria. These findings contribute to understanding the mechanisms of innate immune responses to Gram-positive infections and the role of TLR2 in signal transduction. Further research is needed to fully elucidate the contributions of individual TLR family members to immune responses in vivo.Sepsis, a life-threatening condition caused by bacterial infection, is triggered by both Gram-negative and Gram-positive bacteria. This study investigates how Gram-positive bacteria, specifically through their components peptidoglycan (PGN) and lipoteichoic acid (LTA), activate host cells. The findings show that PGN and LTA, like lipopolysaccharide (LPS) from Gram-negative bacteria, activate the transcription factor NF-κB in host cells such as macrophages. This activation is mediated by Toll-like receptor 2 (TLR2), a member of the Toll-like receptor family. Unlike LPS, which requires serum for signaling, PGN and LTA can activate NF-κB in the absence of serum, indicating a distinct signaling pathway. The study demonstrates that TLR2 is essential for PGN and LTA-induced NF-κB activation, and that CD14, a glycosylphosphatidylinositol-anchored membrane protein, enhances this process. However, TLR2 alone is not sufficient for full activation, suggesting the involvement of additional co-receptors. The results indicate that TLR2 is not only a receptor for LPS but also for PGN and LTA from Gram-positive bacteria, expanding its role in immune responses. The study also highlights the importance of TLR2 in detecting and responding to Gram-positive bacterial components. While TLR4 is crucial for immune responses to Gram-negative bacteria, it may not be involved in responses to Gram-positive bacteria. These findings contribute to understanding the mechanisms of innate immune responses to Gram-positive infections and the role of TLR2 in signal transduction. Further research is needed to fully elucidate the contributions of individual TLR family members to immune responses in vivo.