The structure of the T cell antigen receptor genes in normal and malignant T cells

Abstract

In this review the genomic structure and the RNA transcripts of the α and β chain of the T cell antigen receptor have been discussed. Studies of the structure of TcR β in hematologic malignancies have revealed rearrangement in almost all of the T cell malignancies and a small proportion of non-T cell malignancies. In addition, clonal involvement of T cells in diseases such as Hodgkin's disease, angioimmunoblastic lymphadenopathy, and chronic T cell lymphocytosis have been observed. The study of the structure of the TcR β gene is thus a useful tool for identifying clonal expansions of cells and in conjunction with studies of the immunoglobulin gene structure, and cell surface markers a useful tool for identifying cell lineage. At the present time the evaluation of the structure of the α chain genes has not been as fruitful. However, chromosome translocations involving the TcR α chain genes have been recognized and, in one case, this rearrangement has been in association with a known oncogene. With the isolation of more probes to the α chain region it should be possible to test its utility in identifying clonal populations and cell lineage. The recent isolation of the gamma gene of the T cell will also permit such studies. Preliminary results of studies carried out with a probe to the γ chain gene of the T cell have paralleled results obtained with the TcR β probe (unpublished observation).