APC anti-Siglec-E Antibody anti-Siglec-E - M1304A01,BioLegend,677106

Siglecs (sialic acid binding Ig-like lectins) are type I membrane proteins with an extracellular region containing a sialic acid binding V-set Ig-like domain at the N-terminus, followed by varying numbers of C2-set Ig domains. The cytoplasmic tails of all siglecs have tyrosine based motifs with a signaling function. Siglecs are widely expressed on hematopoietic cells, often in a cell-type-specific manner. Their ligands, sialic acids, are negatively charged monosaccharides found on cell-surface glycoproteins and glycolipids. Studies suggest that siglecs may participate in cell-cell interactions or act as receptors for the entry of viral or bacterial pathogens. In addition, the presence of immunoreceptor tyrosine-based inhibitory motifs (ITIM) in their cytoplasmic domain indicates that these molecules may play a role in the suppression of immunoreceptor signaling. Siglec-E is a mouse CD33-related siglec that selectively regulates early recruitment of neutrophils to the lung in acute lung inflammation induced by lipopolysaccharide. Siglec E-deficient mice exhibit exaggerated neutrophil recruitment that is reversible by using a blockade of the β2 integrin, CD11b. In addition, sialidase treatment of fibrinogen reverses the suppressive effect of Siglec-E on CD11b signaling. This suggests that sialic acid recognition by Siglec-E is required for its inhibitory function. These findings indicate that Siglec-E is an important negative regulator of neutrophil recruitment to the lungs and β2 integrin-dependent signaling.