CD28 (human):Fc (human) (rec.) | CHI-HF-210CD28

CD152 [CTLA-4] and CD28, together with their ligands B7-1 and B7-2, constitute one of the dominant costimulatory pathways that regulate T and B cell responses. CD152 and CD28 are structurally homologous molecules
that are members of the immunoglobulin (Ig) gene superfamily. Both CD152 and CD28 are composed of a single
Ig V-like extracellular domain, a transmembrane domain and an intracellular domain. CD152 and CD28 are both
expressed on the cell surface as disulfide-linked homodimers or as monomers. CD152 was originally identified
as a gene that was specifically expressed by cytotoxic T lymphocytes. However, CD152 transcripts have since
been found in both Th1 and Th2, and CD4+ and CD8+ T cell clones. Whereas, CD28 expression is constitutive
on the surfaces of 95% of CD4+ T cells and 50% of CD8+ T cells and is down regulated upon T cell activation,
CD152 expression is upregulated rapidly following T cell activation and peaks approximately 24 hours following
activation. Although both CD152 and CD28 can bind to the same ligands, CD152 binds to B71 and B72 with
20-100-fold higher affinity than CD28.

Use / Stability
Stable for at least 1 year after receipt when stored at -20°C. Working aliquots are stable for up to 3 months when
stored at -20°C.

Product Specifications
Biological Activity Binds both CD80 (B7-1) and CD86 (B7-2) with high affinity and inhibits CD28 signaling
competitively. Kills the target cell completely.
Purity ≥98% (SDS-PAGE)
Formulation Lyophilized from 0.2μm-filtered solution in PBS.
Reconstitution Reconstitute at 1mg/ml in sterile water.
Add 1X PBS to the desired protein concentration.
Endotoxin Content <0.06EU/μg protein (LAL test; Lonza).