Molecular Genetics of the T Cell-Receptor Beta Chain

Characterization of cDNA and genomic clones encoding the Beta chain of the T-cell receptor for antigen reveals a very close resemblance to immunoglobulin: V, D, J, and C elements; the mechanism of rearrangement; and the potential extent of diversity, explaining the relatively large T-cell repertoire of specificities and the clonal nature of individual responses. Differences with immunoglobulins are evident in the much more heterogeneous V beta sequences, which appear to have additional hypervariable regions. Together these data predict a roughly immunoglobulin-like structure for the receptor, but with potentially significant variation from immunoglobulin in the nature of the combining site(s).