The production and purification of the human T-cell receptors, the CD3εγ and CD3εδ heterodimers: Complex formation and crystallization with OKT3, a therapeutic monoclonal antibody

Abstract

Human CD3 is an essential multisubunit complex that plays a fundamental role in T-cell signalling, T-cell development and surface expression of the αβ T-cell receptor. The CD3 complex comprises the CD3εγ and CD3εδ heterodimers and the CD3ζζ homodimer. Here, the expression of the human CD3εγ and CD3εδ heterodimers, both of which were expressed as single-chain polypeptides, is reported. Following refolding, functional heterodimers were immunoaffinity purified from improperly folded heterodimers using OKT3, a therapeutic monoclonal antibody specific for the CD3ε chain. Subsequently, the Fab fragment of OKT3 was used to complex individually with the CD3εγ and CD3εδ heterodimers. Crystals of scCD..