A glycan marker of activated and functional Tregs

Sialyl Lewis X (sLeX), a tetra-saccharide antigen, is involved in leukocyte trafficking as selectin ligands. Here we found that sLex could serve as a unique surface marker of activated and functional regulatory T cells (Tregs) with immune suppressive function in mice. Flow cytometric and RNA-sequencing analysis on the contact hypersensitivity (CHS) model indicated that sLeX expression was co-relative with the expression of other markers of functional Tregs. In the CHS-elicitation models, the topical injection of sLeX-positive Tregs into the ears suppressed ear inflammation more efficiently than that of sLeX-negative Tregs.