A new childhood T-cell lymphoma established in nude mice and in vitro.

A T-lymphoma cell line was established from a lymph node biopsy of a boy currently alive in complete remission. Neoplastic cells from this biopsy did not grow in vitro, whereas they formed a progressively growing s.c. tumor in splenectomized and sublethally irradiated nude mice and became serially transplantable in splenectomized and sublethally irradiated nude mice with a stable latency time. After the fourth transplant, cells were stored in liquid nitrogen and referred to as ST-4 cells. ST-4 cells display a membrane phenotype and a karyotype similar to that of the biopsy cells. After thawing, ST-4 cells grow both in splenectomized and sublethally irradiated nude mice and in vitro. They do not secrete interferon or interleukin 2, do not have natural killer activity, and do not respond to mitogen or alloantigen stimulation. The stable features of these T-lymphoma cells and the availability of normal autologous lymphocytes from the patient make this in vivo system quite unique and of importance for studies in tumor immunotherapy.