mCD14

mCD14, also known as membrane CD14, is a glycoprotein expressed on the surface of several immune cells, including monocytes, macrophages, and neutrophils. It serves as a co-receptor involved in the innate immune response, primarily recognizing pathogen-associated molecular patterns (PAMPs) such as lipopolysaccharides (LPS) from gram-negative bacteria. By binding to LPS, mCD14 facilitates the activation of Toll-like receptor 4 (TLR4), triggering downstream signaling pathways that lead to the production of pro-inflammatory cytokines and the initiation of inflammatory responses.

The structure of mCD14 typically consists of a leucine-rich repeat (LRR) domain that mediates ligand recognition and binding. It is anchored to the cell membrane via a glycosylphosphatidylinositol (GPI) anchor, allowing it to participate in ligand detection at the cell surface. In addition to its membrane-bound form, a soluble form of CD14 (sCD14) exists, which can circulate in the blood and contribute to immune signaling in various tissues.

Functionally, mCD14 plays a crucial role in host defense against bacterial infections, acting as an initial sensor for bacterial LPS and other PAMPs. Its activation amplifies immune responses by promoting cytokine release, phagocytosis, and subsequent pathogen clearance. Dysregulation of CD14 expression or function has been associated with inflammatory diseases, sepsis, and other conditions involving immune system disturbances.

Research into mCD14 continues to explore its potential as a therapeutic target for modulating immune responses, especially in infectious and inflammatory diseases. Its conserved nature across species highlights its importance in immune defense mechanisms, making it a significant focus of immunological studies.