Siglec-1/CD169 Protein, Human (HEK293, His)

Siglec-1/CD169 is a macrophage-specific adhesion molecule that mediates sialic acid-dependent binding to immune cells, limiting bacterial dissemination and enhancing phagocytosis. In addition to bacterial interactions, it facilitates the uptake of enveloped viruses and promotes macrophage-to-T cell dissemination. Siglec-1/CD169 Protein, Human (HEK293, His) is the recombinant human-derived Siglec-1/CD169 protein, expressed by HEK293 , with C-His labeled tag.

Siglec-1/CD169 emerges as a macrophage-restricted adhesion molecule with a pivotal role in mediating sialic acid-dependent binding to various immune cells, including granulocytes, monocytes, natural killer cells, B-cells, and CD8 T-cells. Its significance lies in limiting bacterial dissemination by engaging sialylated bacteria, thereby promoting effective phagocytosis and antigen presentation crucial for the adaptive immune response. Beyond bacterial interactions, Siglec-1 is implicated in the uptake of enveloped viruses through sialic acid recognition, leading to the formation of intracellular compartments filled with virions (VCCs). This facilitates macrophage-to-T-cell transmission of viruses, including HIV-1 or SARS-CoV-2. Acting as an endocytic receptor, Siglec-1 employs clathrin-dependent endocytosis, exhibiting a preference for alpha-2,3-linked sialic acid. Notably, it binds to SPN/CD43 on T-cells and may play a role in hemopoiesis. Additionally, Siglec-1 contributes to the inhibition of antiviral innate immunity by promoting TBK1 degradation via TYROBP and TRIM27-mediated ubiquitination. In the context of microbial infection, it facilitates viral cytoplasmic entry into activated dendritic cells by recognizing sialylated gangliosides present on the viral membrane.

Human

HEK293

C-His

Q9BZZ2-1 (S20-Q1641)

6614  [NCBI]

200-220 kDa

Greater than 95% as determined by reducing SDS-PAGE.

<1 EU/μg, determined by LAL method.