Cell-surface receptors on macrophages recognize various ligands expressed or newly-exposed on RBC surfaces, which signal macrophages to initiate erythrophagocytosis. All indicated RBC ligands function as “eat me” signals, except for CD47, which is both an “eat me” and a “don’t eat me” signal.3
Abbreviations: βGal: terminal β-Galactose residue; PS: phosphatidylserine; Gas6: growth-arrest 6 protein; MFG-E8: milk-fat globule protein-E8; SIRP-α: signal regulatory protein-α; ASGR: asialo-glycoprotein receptor; CR3: complement receptor 3; FcγR: Fc gamma receptor; PS-R; PS receptor; MER: c-mer proto-oncogene protein; αVβ5: an integrin subtype.
Red text: “don’t eat me” signal; black text: “eat me” signal