High-efficiency Expression and Solubilization of Functional T Cell Antigen Receptor Heterodimers

The T cell receptor (TCR) zeta chain was attached to the TCR alpha and beta extracellular domains to induce efficient expression of alpha beta heterodimers that can recognize complexes of antigen with major histocompatibility complex (MHC) molecules. Chimeric constructs expressed in RBL-2H3 cells were efficiently transported to the cell surface uniquely as disulfide-linked heterodimers. Transfectants were activated by specific antigen-MHC complexes, which demonstrated that the expressed alpha beta was functional and that CD3 was not required for antigen-MHC binding. Constructs with thrombin cleavage sites were efficiently cleaved to soluble disulfide-linked heterodimers. Thus, attachment of TCR zeta domains and protease cleavage sites to TCR alpha and beta induces expression of demonstrably functional heterodimers that can be solubilized.