CTLA-4 Antibodies

CTLA-4/CD152 (Cytotoxic T-Lymphocyte Antigen 4) is a transmembrane T cell inhibitory molecule that is expressed as a covalent homodimer. CTLA-4 is recruited from intracellular vesicles to the immunological synapse beginning 1-2 days after T cell activation. It forms a linear lattice with B7-1 on APC, inducing negative regulatory signals and ending CD28-dependent T cell activation. Mice deleted for CTLA-4 develop lethal autoimmune reactions due to continued T cell activation and poor control by regulatory T cells which constitutively express CTLA-4.