A Leucine Zipper Dimerization Strategy to Generate Soluble T Cell Receptors Using the <i>Escherichia coli</i> Expression System

Abstract

T cell-mediated adaptive immunity plays a key role in immunological surveillance and host control of infectious diseases. A better understanding of T cell receptor (TCR) recognition of pathogen-derived epitopes or cancer-associated neoantigens is the basis for developing T cell-based vaccines and immunotherapies. Studies on the interaction between soluble TCR α:β heterodimers and peptide-bound major histocompatibility complexes (pMHCs) inform underlying mechanisms driving TCR recognition, but not every isolated TCR can be prepared in soluble form for structural and functional studies using conventional methods. Here, taking a challenging HIV-specific TCR as a model, we designed a general leucine zipper (LZ) dimerization strategy for soluble TCR preparation using the Escherichia coli expression system. We report details of TCR construction, inclusion body expression and purification, and protein refolding and purification. Measurements of binding affinity between the TCR and its specific pMHC using surface plasmon resonance (SPR) verify its activity. We conclude that this is a feasible approach to produce challenging TCRs in soluble form, needed for studies related to T cell recognition.

Keywords

• T cell receptor
• protein engineering
• leucine zipper
• <i>E. coli</i> expression
• refolding
• purification