Title : Glycosylation affects ligand binding and function of the activating
natural killer cell receptor 2B4 (
CD244 )
protein
Abstract :
- 2B4 ( CD244 ) is an important activating receptor for the regulation of natural killer (NK) cell responses
- Here we show that 2B4 is heavily and differentially glycosylated in primary human NK cells and NK cell lines
- The differential glycosylation could be attributed to sialic acid residues on N- and O-linked carbohydrates.
- Using a recombinant fusion protein of the extracellular domain of 2B4 , we demonstrate that N-linked glycosylation of 2B4 is essential for the binding to its ligand CD48
- In contrast, sialylation of 2B4 has a negative impact on ligand binding, as the interaction between 2B4 and CD48 is increased after the removal of sialic acids
- This was confirmed in a functional assay system, where the desialylation of NK cells or the inhibition of O-linked glycosylation resulted in increased 2B4-mediated lysis of CD48-expressing tumor target cells
- These data demonstrate that glycosylation has an important impact on 2B4-mediated NK cell function and suggest that regulated changes in glycosylation during NK cell development and activation might be involved in the regulation of NK cell responses