The complexity of immunoregulation has focused attention on the CD4+ T “suppressor” regulatory cell (Treg), which helps maintain balance between immunity and tolerance. An immunoregulatory T‐cell population that upon activation amplifies cellular immune responses was described in murine models more than 30 years ago; however, no study has yet identified a naturally occurring T “inducer” cell type. Here, we report that the ectoenzyme CD39/NTPDase1 (ecto‐nucleoside triphosphate diphosphohydrolase 1) helps to delineate a novel population of human “inducer” CD4+ T cells (Tind) that significantly increases the proliferation and cytokine production of responder T cells in a dose‐dependent manner. Furthermore, this unique Tind subset produces a distinct repertoire of cytokines in comparison to the other CD4+ T‐cell subsets. We propose that this novel CD4+ T‐cell population counterbalances the suppressive activity of suppressor Treg in peripheral blood and serves as a calibrator of immunoregulation.