Figure 1. CD4⁺ T cell populations are defined by differential CD4 CD25 and CD39 expression.

A. Human CD4⁺ T cells were isolated by Ficoll gradients, stained with anti-human CD25 and intracellularly labeled with Foxp3 then analyzed by FACS. B, C. Human CD4⁺ T cells were stained with CD25, Foxp3 and CD39. The additional use of CD39 as a phenotypic marker identifies four distinct CD4⁺ T cell populations.

Mutually exclusive expression of CD73 and CD39 or CD25 by CD4⁺ T cells

D, E. PBMCs obtained from healthy controls were stained with anti-human CD73, CD39 and CD25. Expression of CD73 appeared largely independent of either CD39 or CD25 expression.

F. CD73 was expressed at high levels on CD127^high T cells

Data denote representative findings for ≥ 20 independent experiments