Source

Human / Cynomolgus / Rhesus macaque CD28, Fc Tag (H-CD28-2) is expressed from human 293 cells (HEK293). It contains AA Asn 19 - Pro 152 (Accession # P10747-1).

Predicted N-terminus: Asn 19

Molecular Characterization

This protein carries a human IgG1 Fc tag at the C-terminus.

Endotoxin

Less than 0.01 EU/mg by the LAL method.

Purity

>95% as determined by SDS-PAGE.

Bioactivity

ELISA ；

BIACORE (With our Research Grade Biosimilar Antibody products);

Formulation

Lyophilized from 0.22 μm filtered solution in 50 mM Tris, 100 mM Glycine, 25 mM Arg, 150 mM NaCl, pH7.5. Normally trehalose is added as protectant before lyophilization.

Reconstitution

Please see Certificate of Analysis for specific instructions.

For best performance, we strongly recommend you to follow the reconstitution protocol provided in the CoA.

Storage

For long term storage, the product should be stored at lyophilized state at -20°C or lower.

Please avoid repeated freeze-thaw cycles.

No activity loss was observed after storage at:

4-8°C for 12 months in lyophilized state;

-70°C for 3 months under sterile conditions after reconstitution.

Background

T-cell-specific surface glycoprotein CD28 is also known as TP44, is a single-pass type I membrane protein which contains one Ig-like V-type (immunoglobulin-like) domain. is one of the molecules expressed on T cells that provide co-stimulatory signals, which are required for T cell activation. CD28 is the receptor for CD80 (B7.1) and CD86 (B7.2). When activated by Toll-like receptor ligands, the CD80 expression is upregulated in antigen presenting cells (APCs). The CD86 expression on antigen presenting cells is constitutive. CD28 is the only B7 receptor constitutively expressed on naive T cells.

Reference

(1) Woerly G., et al., 2002, J Leukoc Biol 72 (4): 769–79.

(2) Nunès, J A., et al., 1996, J. Biol. Chem. (UNITED STATES) 271 (3): 1591–8.

(3) Ellis, J H., et al., 2000, J. Immunol. (UNITED STATES) 164 (11): 5805–14.