CD14 is a glycosylphosphatidylinositol (GPI)-anchored membrane glycoprotein primarily expressed on monocytes, macrophages, and some granulocytes. It functions as a pattern recognition receptor (PRR) and plays a crucial role in the innate immune response by recognizing bacterial lipopolysaccharides (LPS), pathogen-associated molecular patterns (PAMPs), and damage-associated molecular patterns (DAMPs). CD14 exists in two forms: membrane-bound CD14 (mCD14) and soluble CD14 (sCD14), which can be secreted by activated cells. It acts as a co-receptor for Toll-like receptor 4 (TLR4) and enhances the immune response to LPS by facilitating its delivery to the TLR4-MD2 complex. Additionally, CD14 is involved in TLR4-independent signaling pathways and contributes to tissue homeostasis by promoting the clearance of apoptotic cells.