CD28 a 44 kD glycoprotein, is a member of the Ig superfamily, expressed on thymocytes, most peripheral T cells, and NK cells, acting as a co-stimulatory receptor of T cell activation. CD28 is expressed on resting T-cells, while the co-inhibitory receptor CTLA-4 is expressed as a on activated T-cells. Both molecules bind CD80 and CD86 on antigen presenting cells, but CTLA4 has higher affinity then CD28. Anti-CD28 along with anti-CD3 can also activate T cells in vitro.

Each lot of antibody has been tested by flow cytometry staining. We suggest use ≤ 0.5 µg per million cells in 100 µl volume of staining buffer. Researchers are recommended to further titrate this antibody at the optimal concentration for each specific application.

Keep the lyophilized antibodies at -20 °C. Once reconstituted with PBS, store at 2 °C - 8 °C for less than 3 weeks or freeze at -20°C for long term storage. Please limit freeze and thaw cycles.