Anti-Human CD3 [Clone OKT-3] - Purified <i>in vivo </i>PLATINUM™ Functional Grade (C2488-GRP)

CD3 is an invariant antigen of the T cell receptor (TCR) belonging to the Ig superfamily1. The CD3/TCR complex is composed of a ⍺β or γδ TCR heterodimer noncovalently associated with invariant CD3 dimers εγ, εδ, and ζζ in a 1:1:1:1 stoichiometry. The TCR mediates recognition of antigenic peptides bound to major histocompatibility complex (MHC) molecules on antigen- presenting cells, while the CD3 portion of the complex transduces activation signals to the T cell nucleus. Together, TCR and CD3 molecules initiate protective immunity against microbes and cancers. OKT-3 was generated by immunizing a BALB/c or CAF1 mouse with human peripheral blood lymphocytes2. Spleen cells were fused with P3x63Ag8.U1 myeloma cells for hybridoma production. OKT-3 was initially developed as a pan-T cell antibody to differentiate between cell types3 and later . became the first monoclonal antibody to be approved for therapy in humans4. OKT-3 acts as an immunosuppressive drug in transplant patients5, type 1 diabetes, and psoriasis6. OKT-3 recognizes, binds, and blocks the CD3 complex of the T cell receptor4 and thereby blocks the generation and function of cytotoxic T cells7. The OKT-3/CD3εγ structure has been resolved6.