Siglec-3/CD33 Protein, Human (HEK293, hFc)

Siglec-3/CD33 protein is a sialic acid-binding lectin that mediates cell-cell interactions and maintains immune cell quiescence. It prefers α-2,3- and α-2,6-linked glycans with sialic acid. Siglec-3/CD33 Protein, Human (HEK293, hFc) is the recombinant human-derived Siglec-3/CD33 protein, expressed by HEK293 , with C-hFc labeled tag.

The Siglec-3/CD33 protein, a sialic-acid-binding immunoglobulin-like lectin, plays a crucial role in mediating cell-cell interactions and maintaining immune cells in a resting state. It exhibits a preference for recognizing and binding alpha-2,3- and more avidly alpha-2,6-linked sialic acid-bearing glycans. Upon engagement with ligands like C1q or sialylated glycoproteins, two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) within CD33's cytoplasmic tail undergo phosphorylation by Src-like kinases such as LCK. These phosphorylated ITIMs serve as docking sites for recruiting and activating protein-tyrosine phosphatases PTPN6/SHP-1 and PTPN11/SHP-2, which, in turn, regulate downstream pathways through dephosphorylation of signaling molecules. CD33's repressive effect on monocyte activation involves phosphoinositide 3-kinase/PI3K. Structurally, the protein forms homodimers through disulfide linkages and interacts with PTPN6/SHP-1 and PTPN11/SHP-2 upon phosphorylation. It also engages with C1QA via its C-terminus, activating CD33 inhibitory motifs.

1.Immobilized Human Siglec-3 at 0.5 μg/mL(100 μl/well) on the plate. Dose response curve for Biotinylated Anti-Siglec-3 Antibody, hFc Tag with the EC₅₀ of 21.8 ng/mL determined by ELISA.
2.Immobilized Human CD33 at 2 μg/mL (100 μL/well) can bind Anti-CD33 Antibody, the ED₅₀ for this effect is 8.312 ng/mL.

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  Immobilized Human CD33 at 2 μg/mL (100 μL/well) can bind Anti-CD33 Antibody, The ED₅₀ for this effect is 8.312 ng/mL.

Human

HEK293

C-hFc

P20138-1/AAH28152.1 (D18-H259, R69G)

945  [NCBI]

Extracellular Domain

DPNFWLQVQESVTVQEGLCVLVPCTFFHPIPYYDKNSPVHGYWFREGAIISGDSPVATNKLDQEVQEETQGRFRLLGDPSRNNCSLSIVDARRRDNGSYFFRMERGSTKYSYKSPQLSVHVTDLTHRPKILIPGTLEPGHSKNLTCSVSWACEQGTPPIFSWLSAAPTSLGPRTTHSSVLIITPRPQDHGTNLTCQVKFAGAGVTTERTIQLNVTYVPQNPTTGIFPGDGSGKQETRAGVVH

68-80 kDa (glycosylation)

≥ 95%, as determined by Bis-Tris PAGE.

Lyophilized powder

1.Lyophilized from a 0.22 μm filtered solution of 20 mM PBS, 8% trehalose, pH 7.4.
2.Lyophilized from a 0.22 μm filtered solution of 20 mM PB, 150 mM NaCl, pH 7.4.
Please refer to the lot-specific COA for specific buffer information.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years from date of receipt. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.