In vitro growth of cutaneous T-cell lymphomas.

It is relatively easy to propagate EB virus-transformed normal and malignant B lymphocytes in vitro. Normal T lymphocytes divide for short periods of time after exposure to many mitogens. Exposure of normal T lymphocytes to lymphocyte-conditioned medium (LCM) permits them to divide for longer periods of time, but permanent cell lines cannot be established. Intial attempts to grow malignant T cells from patients with cutaneous T-cell lymphomas (CTCL) in unsupplemented growth medium resulted in the establishment of four EB virus-transformed B-lymphoblastoid lines. The responses of CTCL cells to mitogens and LCM varied from unresponsive to near normal. Subsequent attempts to grow CTCL cells in medium supplemented with mitogens or LCM resulted in the establishment of two cell lines lacking B-cell markers or EB virus. The cells of both lines initially had the ability to form E rosettes, although one of the lines has lost this ability with passage. The two lines can be distinguished from normal T cells by having some or all of the following properties: long-term proliferation, tumorigenecity in nude mice, gradual loss of dependence on mitogen or LCM, and convoluted nuclear morphology.