小胶质细胞是非常重要的免疫细胞，它广泛分布于中枢神经系统，能持续地观察和感知周围微环境， 一方面通过释放各种细胞炎症因子平衡机体的免疫反应，另一方面通过吞噬突触和细胞调节神经网络功 能。小胶质细胞的功能失调是神经退行性疾病发生或加剧的主要机制，因此恢复小胶质细胞的功能可能是 一种潜在的治疗模式。CD22是唾液酸结合免疫球蛋白型凝集素家族的重要成员，通常表达于B细胞表面， 起到免疫抑制作用。近期，CD22 被证明能通过小胶质细胞改善老年小鼠的认知功能，这一发现有望使 CD22成为治疗神经退行性疾病的新靶点。

Microglia are very important immune cells, which are widely distributed in the central nervous system. They continuously monitor and sense the surrounding microenvironment, balancing the body's immune response by releasing various cellular inflammatory factors on the one hand, and regulating neural network function through phagocytosis of synapses and cells on the other. Dysfunction of microglia is a primary mechanism involved in the onset or exacerbation of neurodegenerative diseases, thus restoring microglial function may represent a potential therapeutic modality. CD22, an important member of the sialic acid-binding immunoglobulin-like lectin family, is typically expressed on the surface of B cells and serves an immunoinhibitory role. Recently, CD22 has been shown to improve cognitive function in aged mice through microglia, a discovery that holds promise for CD22 to become a novel target in the treatment of neurodegenerative diseases.