Human Siglec-2 (176-687), His Tag (SI2-H5228) is expressed from human 293 cells (HEK293). It contains AA Trp 176 - Arg 687 (Accession # P20273-1).
Predicted N-terminus: Trp 176
This protein carries a polyhistidine tag at the C-terminus.
The protein has a calculated MW of 58.1 kDa. The protein migrates as 90-100 kDa under reducing (R) condition (SDS-PAGE) due to glycosylation.
Less than 1.0 EU per μg by the LAL method.
>95% as determined by SDS-PAGE.
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4. Normally trehalose is added as protectant before lyophilization.
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Please see Certificate of Analysis for specific instructions.
For best performance, we strongly recommend you to follow the reconstitution protocol provided in the CoA.
For long term storage, the product should be stored at lyophilized state at -20°C or lower.
Please avoid repeated freeze-thaw cycles.
This product is stable after storage at:
- -20°C to -70°C for 12 months in lyophilized state;
- -70°C for 3 months under sterile conditions after reconstitution.
Human Siglec-2 (176-687), His Tag on SDS-PAGE under reducing (R) condition. The gel was stained overnight with Coomassie Blue. The purity of the protein is greater than 95%.
Immobilized Human Siglec-2 (176-687), His Tag (Cat. No. SI2-H5228) at 2 μg/mL (100 μL/well) can bind Anti-Human CD22 MAb, Human IgG1 with a linear range of 0.1-2 ng/mL (QC tested).
Anti-Human CD22 MAb (human IgG1) captured on CM5 chip via Anti-Human IgG Fc antibodies surface, can bind Human Siglec-2 (176-687), His Tag (Cat. No. SI2-H5228) with an affinity constant of 11.5 nM as determined in a SPR assay (Biacore T200) (Routinely tested).
Loaded Anti-Human CD22 MAb (human IgG1) on AHC Biosensor, can bind Human Siglec-2 (176-687), His Tag (Cat. No. SI2-H5228) with an affinity constant of 34.4 nM as determined in BLI assay (ForteBio Octet Red96e) (Routinely tested).
CAR阳性表达率检测（Evaluation of CAR expression ）
FACS Analysis of Anti-CD22 CAR Expression
293 cells were transfected with anti-CD22-scFv and RFP tag. 2e5 of the cells were first stained with B. Human Siglec-2 (176-687), His Tag (Cat. No. SI2-H5228, 3 μg/mL) and C. His Tag Protein Control, followed by FITC Anti-6xHis Tag Antibody. A. Non-transfected 293 cells and C. His Tag Protein Control were used as negative control. RFP was used to evaluate CAR (anti-CD22-scFv) expression and FITC was used to evaluate the binding activity of Human Siglec-2 (176-687), His Tag (Cat. No. SI2-H5228).
B-cell receptor CD22 is also known as Sialic acid-binding Ig-like lectin 2 (Siglec-2), B-lymphocyte cell adhesion molecule (BL-CAM), T-cell surface antigen Leu-14, which belongs to the immunoglobulin superfamily and SIGLEC (sialic acid binding Ig-like lectin) family. CD22 mediates B-cell B-cell interactions, and may be involved in the localization of B-cells in lymphoid tissues. Siglec-2 / CD22 binds sialylated glycoproteins, one of which is CD45. Siglec2 / CD22 plays a role in positive regulation through interaction with Src family tyrosine kinases and may also act as an inhibitory receptor by recruiting cytoplasmic phosphatases via their SH2 domains that block signal transduction through dephosphorylation of signaling molecules.