CST, 16399S, Phospho-CD28 (Tyr191) (E5B9Z) Rabbit Monoclonal Antibody

Monoclonal Antibody for studying CD28 (Tyr191) phosphate. Validated for Western Blotting,Immunoprecipitation. Available in 2 sizes. Highly specific and rigorously validated in-house, Phospho-CD28 (Tyr191) (E5B9Z) Rabbit Monoclonal Antibody (CST #16399) is ready to ship. Product Usage Information Western Blotting: 1:1000 Immunoprecipitation: 1:200 Storage Supplied in 10 mM sodium HEPES (pH 7.5), 150 mM NaCl, 100 µg/ml BSA, 50% glycerol and less than 0.02% sodium azide. Store at -20°C. Do not aliquot the antibody. Protocol Available protocols: Western Blotting, Immunoprecipitation Specificity / Sensitivity Phospho-CD28 (Tyr191) (E5B9Z) Rabbit Monoclonal Antibody recognizes endogenous levels of CD28 protein only when phosphorylated at Tyr191. This antibody shows cross-reactivity with phosphorylated EGFR, ERBB2, and CSF1R, and detects a 70-80 kDa band of unknown origin in some treated cell lines. Species Reactivity: Human, Mouse Source / Purification Monoclonal antibody is produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Tyr191 of human CD28 protein. Background CD28 is a transmembrane glycoprotein expressed by T cells as well as some other hematopoietic cells (1, 2). T cell activation requires T cell receptor (TCR) recognition of antigen presented in the context of MHC molecules. CD28 acts as a T cell costimulatory receptor, and interaction of CD28 with its ligands CD80 or CD86 provides the second signal required for naïve T cell activation (3-5). Activation of naïve T cells in the absence of CD28 stimulation can result in a state of T cell anergy, or unresponsiveness (3). CD28 signals through cytoplasmic phospho-tyrosine motifs that bind several SH2 or SH3 domain-containing proteins involved in T cell activation (2). Recently, CD28 was demonstrated to be a preferred target of PD-1-mediated dephosphorylation. Consistently, CD28 expression was required for T cell proliferation following PD-1 blockade and CD28 stimulation was required for effective anti-PD-1 cancer immunotherapy in mice (6, 7). Several CD28 isoforms are produced by alternative splicing (8). Alternate Names CD28; CD28 antigen; CD28 molecule; MGC138290; T-cell-specific surface glycoprotein CD28; TP44 Specification REACTIVITY: H M SENSITIVITY: Endogenous MW (kDa): 40 Source/Isotype: Rabbit IgG