Rearranged T lymphocyte antigen receptor genes as markers of malignant T cells.

We have recently cloned a number of canine T cell receptor (TCR) Vbeta genes using degenerate oligonucleotides. From the DNA sequences of the resulting clones and the canine Vbeta gene sequences in the literature, seven distinct canine TCR Vbeta genes were identified. Vbeta specific PCR primers were designed for each of the seven TCR Vbeta genes such that under defined conditions, each primer could only amplify a specific TCR Vbeta gene in conjunction with the same 3' constant region (Cbeta) primer. By performing RT-PCR on RNA derived from a source containing T lymphocytes, the presence and expansion of T cells expressing a particular Vbeta gene could be detected. Moreover, the clonality or diversity of a T cell population under analysis could be easily determined by the VDJ junctional sequence of the amplified Vbeta PCR product, in the form of a "DNA fingerprint". These findings have been used to detect canine T cell lymphoma, and could potentially be used to monitor the remission of T cell malignancies in response to treatment.