THEOPHYLLINE MODULATION OF E-ROSETTE FORMATION - INDICATOR OF T-CELL MATURATION

Abstract

The binding of unsensitized sheep erythrocytes [E] is a characteristic of human thymus dependent T lymphocytes. The effect of theophylline on E-rosette formation was investigated using cells from normal individuals, and patients with immunodeficiency or acute lymphoblastic leukemia. The influence of the drug on distinct T lymphocyte subpopulations was correlated. Three subpopulations of E-rosetting T lymphocytes could be delineated: theophylline-sensitve T [thymus-derived] cells which lost the capacity to form E-rosettes following treatment, theophylline-resistant T cells which were unaffected by the drug and theophylline-dependent cells which acquired the ability to form E-rosettes following incubation with theophylline. The action of theophylline was dose-dependent, temperature-dependent and reversible. Reversibility or re-expression of the receptor for sheep red cells could be blocked by the addition of puromycin. In peripheral blood, E-rosetting T lymphocytes were roughly divided into 2 equal populations, one sensitive, the other resistant. Thymocytes were entirely theophylline-resistant, whereas a small population of cells in peripheral blood and bone marrow were induced to become E-rosetting in the presence of theophylline. Induction by theophylline may be effective at a distinct stage of precursor T cell differentiation.