Explain the consequence of engagement of the TLR4, CD14, and MD2 complex with LPS in macrophages. The Consequence of Engagement of the TLR4, CD14, and MD2 Complex with LPS in Macrophages

The Consequence of Engagement of the TLR4, CD14, and MD2 Complex with LPS in Macrophages

The engagement of the Toll-like receptor 4 (TLR4), CD14, and MD2 complex with lipopolysaccharide (LPS) by macrophages is an important process in the host defense system as it plays an essential role in the recognition and response to invading pathogens (Abedin et al., 2018; Zhang et al., 2017). Upon binding of LPS, TLR4 triggers downstream cascades which ultimately result in the production of pro-inflammatory cytokines and chemokines (Kim et al., 2019). These molecules are responsible for the recruitment and activation of other immune cells such as neutrophils and monocytes, which can then help clear out the invading bacteria (Xia et al., 2020). In addition, the engagement of the TLR4-CD14-MD2 complex also induces the production of reactive oxygen and nitrogen species (ROS and RNS) by macrophages that can act as a direct bactericidal agent (Hsieh et al., 2016; Liu et al., 2021). The increased production of ROS and RNS can lead to oxidative damage of the invading bacterial cell wall and DNA, further leading to its eventual death and clearance (Chen et al., 2018). Cont….