Role of adenosine deaminase in the early stages of precursor T cell maturation.

The role of adenosine deaminase in the initial stages of precursor T cell differentiation was examined in patients with adenosine deaminase deficiency. Incubation of precursor T cells from adenosine deaminase-deficient patients directly in contact with thymic epithelial monolayers induced receptors for sheep erythrocytes (E rosettes). Pretreatment of these monolayers with erythro-9-(2-hydroxy-3-nonyl) adenine, an inhibitor of adenosine deaminase, prevented differentiation only of adenosine deaminase-deficient T cell precursors, and this could be restored by providing adenosine deaminase following the incubation with thymic epithelial cells. These studies indicate a role for adenosine deaminase in the earliest stages of T cell differentiation.