T-CELL RECEPTOR-EXTRACELLULAR CONSTANT REGIONS AS HETERO-CROSS-LINKERS FOR IMMUNOGLOBULIN VARIABLE REGIONS

The T cell receptor alpha and beta chains are covalently linked via a disulfide bond in their extracellular constant regions. To use these d omains as specific hetero-cross-linkers of two different polypeptides, we created genetic constructs encoding a chimeric antibody Fab fragme nt in which mouse immunoglobulin constant regions from a phosphorylcho line-specific antibody were substituted for human alphabeta-T cell rec eptor (TCR) extracellular constant regions (for solubilization, the tr ansmembrane- and cytoplasmic-regions of the receptor were deleted). Th ese constructs, i.e., chimeric heavy (V(H)C(beta)C(kappa)) and light ( V(L)C(alpha)) chains, were cotransfected into murine SP2/0 myeloma cel ls for expression. Cells transfected with the genes expressed mRNAs fo r chimeric heavy and light chains. Without CD3 molecules, the two chim eric chains specifically associated via a disulfide bond to form a chi meric Fab fragment in the cells. These data indicate that the TCR C(al pha)- and C(beta)-regions might be used as potent specific hetero-cros s-linkers for protein engineering.