HETERODIMERIC, DISULFIDE-LINKED ALPHA-BETA T-CELL RECEPTORS IN SOLUTION

Structural and functional analysis of T cell receptor (TcR)-ligand binding would be greatly advanced by the availability of an intact, assembled TcR in soluble form. We have produced such a molecule, by splicing the extracellular domains of a TcR to the glycosyl phosphatidylinositol membrane anchor sequences of Thy-1. The molecule is expressed in the absence of CD3 on the cell surface, and can be cleaved from the membrane by treatment with phosphatidylinositol-specific phospholipase C. The alpha and beta chains of the soluble molecule are paired in the native conformation as judged by reactivity with the anti-V-beta-8 monoclonal antibody F23.1, and with the anti-clonotypic monoclonal antibody 1B2; it is a disulfide-linked dimer with a mol. mass of 95 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions, and 47 kDa after reduction. We conclude that we have generated an alpha/beta-TcR in soluble form.