Proximity labeling of Siglec-1 counter-receptors on activated regulatory T cells using soluble Siglec-1-HRP multimers

Siglec-1 is a macrophage lectin-like receptor that mediates sialic acid-dependent cellular interactions. It was shown previously to promote inflammation in autoimmune disease through suppressing the expansion of regulatory T cells (Tregs). We have investigated the molecular basis for Siglec-1 binding to these cells using in vitro-induced Tregs. A proximity labelling and proteomics strategy were used to identify glycoproteins expressed by activated Tregs that may function as Siglec-1 counter-receptors.