Identical Vβ T-cell receptor genes used in alloreactive cytotoxic and antigen plus I–A specific helper T cells

Abstract

T lymphocytes involved in the cellular immune response carry cell-surface receptors, responsible for antigen and self recognition. This T-cell receptor molecule is a heterodimeric protein consisting of disulphide-linked α- and β-chains with variable (V) and constant (C) regions^1–5. Several complementary DNA and genomic DNA clones have been isolated and characterized^6–12. These analyses showed that the genomic arrangement and rearrangement of T-cell receptor genes using V_T, diversity (D_T), joining (J_T) and C_T gene segments is very similar to the structure of the known immunoglobulin genes (see ref. 13 for review). We have isolated two cDNA clones from an allospecific cytotoxic T cell, one of which shows a productive V_β–J_β–C_β 1 rearrangement without an intervening D_β segment. This V_β gene segment is identical to the V_β gene expressed in a helper T-cell clone specific for chicken red blood cells and H–2I^b (ref. 14). The other clone carries the C_β2 gene of the T-cell receptor, but the C_β2 sequence is preceded by a DNA sequence that does not show any similarity to V_β or J_β sequences.