Functional characterization of an IL-7-dependent CD4+CD8αα+ Th3-type malignant cell line derived from a patient with a cutaneous T-cell lymphoma

CDR3 of the functional rearranged T-cell receptor variable β region (TCR-Vβ) transcript was sequenced in order to demonstrate for the first time the identity between a long-term cultured T-cell line derived from a cutaneous T-cell lymphoma (CTCL) patient and the malignant T-cell clone present in the blood. The patient's peripheral blood lymphocyte-derived cultured T-cell line had a CD3+Vβ22+CD4+CD8αα+CD25- type. It was named Pno and had been cultured for more than 1 year. Both fresh and long- term - cultured tumor cells proliferated highly in response to interleukin-7 (IL-7), and exogeneous IL-7 prevented Pno lymphocytes from apoptosis and maintained high levels of Bcl-2 expression. This unique malignant cloned lymphocyte line was further used to carry out functional studies. The results indicated that the CD3/TCR structures expressed by the Pno lymphocytes were functional because an immobilized anti-CD3 monoclonal antibody (mAb) or the combination of a soluble anti-CD3 mAb with submit...