Selective loss of the expression of OKT-4 or leu-3A defined antigen by 12-0-tetradecanoylphorbol-13-acetate (TPA) in human lymphoid cells

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Abstract
In ten human malignant T-cell lines (HPB-ALL, HPB-MLT, CCRF-CEM, RPMI-8402, MOLT-4, JM, P12/Ichikawa, TALL-1, SKW-3, HUT-102), the expression of the antigen defined by OKT-4 or Leu-3A monoclonal antibody was remarkably decreased after a short incubation (1 hr) with 12-0-tetradecanoylphorbol-13-acetate (TPA) (1.6 nM). This phenomenon was also observed in all types of cells tested, including two lymphoblastoid cell lines with B-cell properties (RPMI-6410 and RPMI-8392), thumus cells from three children, peripheral blood lymphocytes from four normal individuals, and fresh neoplastic T cells from a case of T-cell acute lympho-blastic leukemia (ALL) and a case of T-cell lymphoma. The presence of puromycin (10 μM), cycloheximide (35 μM), or retinoic acid (1.0 μM), had no effect on the TPA-induced loss of OKT-4 defined antigen. Incubation at 4°C or with lidocaine (4 mM) partially prevented this effect of TPA, and the presence of sodium azide (150 mM) did so totally. Recovery of antigen expression occurred 24 hours after cessation of TPA treatment. Comparative study using several phorbols other than TPA showed that this effect accorded with the tumor promotor activity of the compounds, but the phenomenon appears to be at the membrane level, not necessarily as a result of TPA-induced cellular differentiation.