CD169e

CD169e, also known as Sialoadhesin or Siglec-1, is a type I transmembrane protein belonging to the Siglec (sialic acid-binding immunoglobulin-like lectin) family. It is primarily expressed on macrophages and dendritic cells, particularly in certain lymphoid tissues and inflamed sites. The protein's extracellular domain contains a unique N-terminal V-set immunoglobulin-like domain followed by a series of C2-set immunoglobulin-like domains. This structure allows CD169e to bind to sialic acid residues found on glycans of other cells or in the extracellular matrix.

The function of CD169e is multifaceted and involves cell-cell interactions, immune regulation, and pathogen recognition. Its ability to bind sialic acids suggests a role in modulating immune cell interactions and potentially in the uptake and presentation of antigens. CD169e has been implicated in the capture and retention of pathogens, such as viruses and bacteria, by macrophages. Furthermore, it plays a role in the migration and trafficking of immune cells. Research has indicated that CD169e can influence the differentiation and activation of immune cells, contributing to the overall immune response. Its expression is often upregulated in inflammatory conditions, highlighting its involvement in disease processes.