Presence of T-cell receptor mRNA in functionally distinct T cells and elevation during intrathymic differentiation

Understanding the differentiation of functionally distinct subsets of T lymphocytes is essential to unravel their crucial role in the immune response and awaits knowledge of the assembly and expression of genes encoding the T-cell receptor. Recently, we have cloned and sequenced complementary DNA that may specify part of the human T-cell receptor¹. The deduced protein sequence showed extensive similarity to the entire length of mammalian immunoglobulin light chains¹. In addition, sequences corresponding to this message undergo somatic rearrangements² and are assembled from non-contiguous genomic sequences into a single mRNA molecule³, a mechanism similar to those found in the generation of immunoglobulin messages⁴. A related molecule from the mouse was also isolated independently by Hedrick et al.⁵. Here we show that the putative T-cell receptor mRNA is expressed at a relatively high level during intrathymic differentiation before decreasing about 10-20-fold in normal, mature peripheral blood T cells and that it can also be detected in T-cell clones with helper and cytotoxic functions, as well as in at least one clone with suppressor properties.