The CD28 protein is critical for T cell activation, enhancing proliferation, cytokine production, and survival. When linked to TCR/CD3 and CD40L, CD28 promotes the production of IL4 and IL10, thereby regulating immune responses. CD28 Protein, Human/Cynomolgus/Rhesus Macaque (Biotinylated, HEK293, Fc-Avi) is the recombinant human, cynomolgus-derived CD28 protein, expressed by HEK293 , with C-Avi, C-hFc labeled tag.