CD28 (PE)

Chicken CD28 antigen is a type I transmembrane monomeric glycoprotein which does not contain the cysteine residues that form disulfide-linked covalent homodimers found in the mammalian counterpart. This may reduce the avidity of binding to individual ligand molecules expected to be present on Ag presenting cells. Peripheral gamma/delta+ T cells are CD28-negative.1 Monoclonal antibodies against CD28 have a costimulatory effect on T cells stimulated by phorbol myristate acetate (PMA), concanavalin A or MAbs against the avian T cell receptor (TCR). Both Vbeta1- and Vbeta2-expressing cells respond equally well to stimulation with anti-CD28 in combination with PMA. These responses are resistant to cyclosporin A, but inhibited by herbimycin A, suggesting that CD28 employs a signalling pathway at least partly distinct from that triggered by TCR/CD3.2

Applications:
• Flow cytometry 1
• Immunoprecipitation 1
• In vitro T-cell costimulation 2

Recommended Dilution:
Flow Cytometry: ≤ 0.2ug/10e6 cells
Optimal dilutions to be determined by the researcher.

Storage and Stability:
May be stored at 4°C for short-term only. For long-term storage and to avoid repeated freezing and thawing, aliquot and add glycerol (40-50%). Store at -20°C or colder. Aliquots are stable for at least 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.