SIGLEC11 (sialic acid binding Ig-like lectin 11) encodes an inhibitory receptor predominantly expressed on microglia that recognizes α-2,8-linked sialic acids and oligosialic acids enriched in brain tissue 12. The protein functions as a neuroprotective receptor by maintaining microglial homeostasis through inhibitory signaling pathways that suppress inflammatory responses and phagocytosis 23. SIGLEC11 emerged through human-specific gene conversion, becoming uniquely expressed in human brain microglia compared to other primates 14. In disease contexts, SIGLEC11 has been identified as a genetic risk factor for Alzheimer's disease through Mendelian randomization studies, with potential roles in microglial phagocytosis of amyloid-β plaques 56. Additionally, SIGLEC11 promotes M2 macrophage polarization through AKT-mTOR signaling in gastric cancer, demonstrating immunosuppressive functions beyond the nervous system 7. Transgenic mouse studies show that SIGLEC11 expression reduces brain inflammation, oxidative stress, and age-related neuronal loss, particularly in the substantia nigra, by suppressing pro-inflammatory cytokines and complement pathways 3. This makes SIGLEC11 a promising therapeutic target for neurodegenerative diseases.