Anti-CD28 (C-Term) Rabbit Monoclonal Antibody (RM404)

CD28 is a glycoprotein and member of the CD28/B7 family of co-stimulatory receptors that promotes T cell activation. Alternative splicing of CD28 produces one full-length long isoform, CD28 long, and three short isoforms, CD28a, CD28b, and CD28c. CD28 long exists as a membrane-bound homodimer and contains a leader peptide, an extracellular immunoglobulin variable (IgV) domain that interacts with the co-stimulatory molecules CD80 (Cay-32013) or CD86 and a cytoplasmic tail that mediates the association with the signal transduction enzyme PI3K and is critical for T cell activation. CD28a, CD28b, and CD28c contain truncated extracellular or transmembrane domains and exist as soluble monomers (CD28a) or membrane-bound homodimers (CD28b and CD28c). CD28 is constitutively expressed on the surface of T cells, upregulated by antigen-presenting cells (APCs) displaying MHC-bound antigen, and downregulated after T cell activation. CD28 competes with CTLA-4 (Cay-32009), an inhibitor of T cell activation also expressed on T cells, for binding to CD80 or CD86, promoting T cell activation by inducing the production of cytokines, such as IL-2 and IFN-gamma, and decreasing the T cell receptor activation threshold. Genetic deletion of Cd28 abolishes cellular infiltration and bone erosion in the joints and decreases serum levels of anti-collagen-IgG in a mouse model of collagen-induced arthritis. CD28 levels are decreased on plasma cells isolated from patients with multiple myeloma and this decrease is associated with disease progression and poor prognosis. CD28 SNPs have been found in individuals with sporadic breast cancer. Cayman's CD28 (C-Term) Rabbit Monoclonal Antibody (RM404) can be used for immunohistochemistry (IHC) and Western blot (WB) applications.Synonyms: T cell-specific Surface Glycoprotein CD28, TP44. Immunogen: Peptide from the C-terminal region of human CD28. Clone Designation: RM404. Formulation: (Request formulation change), 100 µl of protein A-affinity purified monoclonal antibody. Storage Buffer: PBS with 50% glycerol, 1% BSA, and 0.09% sodium azide. Host: Rabbit. Isotype: IgG. Applications: IHC, WB. Cross Reactivity: (+) CD28.