Tumor-promoting phorbol esters selectively abrogate the expression of the T4 differentiation antigen expressed on normal and malignant (Sézary) T helper lymphocytes.

Abstract

12-O-tetradecanoylphorbol-13-acetate (TPA) selectively abrogates, in nanomolar concentrations, the expression of the T4 differentiation antigen, as defined by the monoclonal anti-T4 antibody on Il-2[interleukin-2]-producing T helper lymphocytes from normal donors and on T helper lymphocytes from a patient with malignant T cell lymphoma (Sezary''s syndrome); this compound does not affect the expression of cell surface antigens as defined by the antibodies anti-OKT3, -T6, -T8, -T11, Ia or anti-surface Ig. Abrogation of the T4 antigen expression is concentration dependent, completed within 8 h of incubation at 37.degree. C, does not occur at 4.degree. C and is reversible. Only those phorbol-esters known to have tumor-promoting activity in vivo affect the T4 antigen, while nonpromoting compounds are ineffective.