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.
!!!All Science Journal Classification (ASJC) codes