An immunoglobulin heavy-chain gene is altered in two T-cell clones

Abstract

Thymus-derived lymphocytes (T cells) show a high degree of discrimination in their responses to various antigens, very similar to the specificity repertoire of antibody-producing B cells. The nature of the T-cell receptor which mediates antigen recognition is obscure, but the ability to discriminate between antigenic specificities implies a range of receptor specificities. Many serological and genetic data suggest that T-cell receptors use the immunoglobulin heavy (H)-chain variable (V) region genes but do not carry the antigenic determinants of the immunoglobulin H-chain constant (C) regions; they also do not seem to carry conventional light (L)-chain V- or C-region determinants1–3. In B cells and derivatives the expression of immunoglobulin genes is manifested, at the DNA level, by an alteration of the restriction enzyme patterns of both the H and L immunoglobulin genes4–9. Specifically, V-gene integration involves joining of a V gene with a J segment (in the case of the H chain probably through an intermediate D segment)4,6,7 so that sites for restriction enzymes will undergo changes in cells in which V–J joining has occurred. Here, we describe Southern filter hybridization experiments10 using Cμ and Cκ probes on the DNA of individual T-cell clones from mice, and present evidence for alteration of sequences adjacent to the Cμ gene in the cells.