Description
Formulation
Supplied in 10 mM NaH2PO4, 150 mM NaCl, pH7.2, Low Endotoxin, Azide-free.
Storage
Stable for 12 months when stored at 4°C. Do not aliquot the antibody.
Protocol
Available protocols: Functional
Specificity / Sensitivity
Human CD28 Activating (CD28.2) Mouse Monoclonal Antibody (Low Endotoxin, Azide-free) recognizes endogenous levels of CD28 protein.
Species Reactivity: Human
Source / Purification
Monoclonal antibody is produced using cells transfected with human CD28 and purified via affinity chromatography.
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
