Sialoadhesin (CD169) and Scavenger receptor class A member 1 (SR-A1) (CD169/SR-A1)

Sialoadhesin (CD169) and Scavenger receptor class A member 1 (SR-A1) are distinct cell-surface receptors primarily expressed on macrophage populations, playing pivotal roles in innate immunity and homeostasis. CD169, a member of the Siglec family, is predominantly found on subcapsular sinus macrophages in lymph nodes and marginal zone macrophages in the spleen, where it facilitates the capture of sialylated pathogens and the initiation of immune responses (UniProt Q9BZZ2; PMID: 24613458). SR-A1 is a multi-ligand scavenger receptor involved in the endocytosis of modified low-density lipoproteins and various environmental and microbial antigens, contributing significantly to the pathogenesis of atherosclerosis and host defense (UniProt P21757; PMID: 12490951). While these receptors are separate gene products, they are often grouped in the context of macrophage-targeted therapies, such as nanoparticles designed to exploit their high phagocytic capacity for vaccine delivery or anti-inflammatory drug targeting. In disease states, CD169 serves as a sensitive biomarker for type I interferon activity in autoimmune conditions and viral infections like COVID-19, while SR-A1 is a target for modulating lipid accumulation in foam cells (PMID: 32835077). Therapeutic strategies involving these receptors typically focus on either utilizing them for targeted delivery or modulating their activity to control inflammation and lipid metabolism.

Other names

Siglec-1Sialic acid-binding Ig-like lectin 1SNMSR1CD204Macrophage scavenger receptor 1

Modulation of receptor-mediated endocytosis and signaling to regulate immune activation or lipid uptake.