Transcription of unrearranged T cell receptor δ genes in CD3- major histocompatibility complex-unrestricted cytotoxic cells

Transcription of the T cell receptor (TcR) δ gene was detected in clones and in enriched populations of CD3^- major histocompatibility complex-unrestricted cytotoxic cells. The transcripts were derived, at least in part, from unrearranged TcR δ genes, as shown by hybridization to a synthetic oligonucleotide probe corresponding to germ-line sequences just upstream of J(δ)1. Transcripts from unrearranged TcR δ genes are similar in size to those from productively rearranged genes. The fact that the bulk of δ transcripts was derived from unrearranged genes was supported by the observation that TcR δ gene rearrangements were not detected in DNA isolated from an enriched CD3^- cytotoxic cell population. Transcription of the TcR δ gene in CD3^- cytotoxic cells is consistent with the notion that these cells belong to a T cell lineage.