|Detection of CD37 in Human Monocytes by Flow Cytometry. Human monocytes were stained with Mouse Anti-Human CD37 Fluorescein‑conjugated Monoclonal Antibody (Catalog # FAB4625F, filled histogram) or isotype control antibody (Catalog # IC003F, open histogram). View our protocol for Staining Membrane-associated Proteins.|
CD37, also known as TSPAN26, is a 40-60 kDa palmitoylated tetraspanin superfamily glycoprotein that is expressed principally by B cells, but also by T cells, NK cells and APCs. CD37 directly associates with multiple partners, incuding Dectin-1 on APCs, Integrin alpha 4 beta 1 on plasma cells, MHC-II molecules on dendritic cells, and additional tetraspanins such as CD53, CD81, and CD82 on various cell types. It appears to play a role in immune downmodulation, as its association with Dectin-1 reduces APC cytokine release, and its association with MHC-II depresses T-cell stimulation. Consistent with membership in the tetraspanin family, CD37 has cytoplasmic N- and C-termini. Notably perhaps, signaling through the N-terminus initiates cell death while signaling through the C-terminus promotes cell survival. Over amino acids constituting the CD37 extracellular domain, human and mouse share 69% amino acid sequence identity.