Natural and concanavalin A-induced cytotoxic activity towards continuously growing B lymphocytes derived from patients with cutaneous T-cell lymphoma.

Continuously growing T- and B-cell lines were derived from peripheral blood, affected skin, and lymph nodes of patients with mycosis fungoides (MF) and Sézary syndrome (SS). Two lymphoblastoid cell lines (MF-13 and SS-2) were Epstein-Barr virus (EBV)-transformed B cells evaluated by surface immunoglobulin, lack of E-rosette formation, positive EBV nuclear antibody test, and secretion of IgM antibody in a plaque-forming cell assay. Analysis of the natural-killer-cell activity using peripheral blood lymphocytes from patients with MF and healthy control persons towards MF-13 and SS-2 target cells suggested resistance to lysis even in tests supplemented with 1,000 IU/ml human gamma-interferon. However, the cell lines were not per se completely resistant to lysis because lymphocytes from control persons showed significant cytotoxicity in an 18-h assay supplemented with 2 micrograms/ml concanavalin A.