Sialic acid-binding immunoglobulin-like lectin 1 (Siglec-1)

Sialic acid-binding immunoglobulin-like lectin 1 (Siglec-1, also called Sialoadhesin or CD169) is a macrophage-restricted cell surface receptor belonging to the immunoglobulin superfamily and the I-type lectin subfamily. It is characterized by 17 immunoglobulin-like domains, making it the largest Siglec family member, and is primarily expressed on activated macrophages and dendritic cells. Siglec-1 binds to sialic acid-containing glycoconjugates on cell surfaces, mediating cell adhesion, immune surveillance, endocytosis, and antigen presentation. It plays a central role in modulating immune responses, including phagocytosis of sialylated pathogens and facilitating trans-infection of viruses such as HIV-1 through binding to viral sialic acids. Its increased expression has been observed in various disease contexts (including infections, autoimmune disorders, atherosclerosis, and cancer) and its unique structure and immunomodulatory functions have made it a focus for both biomarker use and as a potential immunotherapeutic target.

Other names

SialoadhesinCD169SIGLEC1

Inhibition or modulation of Siglec-1 may: Alter antigen presentation; Block cell adhesion between macrophages and pathogens or tumor cells; Inhibit viral dissemination via prevention of viral interactions with Siglec-1 on macrophages; Modulate immune activation or dampening through altered cell signaling