Inhibition of T lymphocyte mitogenesis by 1,25-dihydroxyvitamin D3 (calcitriol)

J Clin Invest. 1984 Oct;74(4):1451-5. doi: 10.1172/JCI111557.


Recent studies have suggested that vitamin D may have other important biologic activities in addition to its well-characterized role in the maintenance of calcium homeostasis. Discovery of cytosolic receptors for vitamin D in human peripheral blood monocytes and lectin-stimulated lymphocytes prompted us to study the effects of 1,25-dihydroxyvitamin D3 (calcitriol), the most biologically active metabolite of vitamin D, upon phytohemagglutinin (PHA)-induced lymphocyte blast transformation. We have found that calcitriol is a potent inhibitor of PHA-induced lymphocyte proliferation, achieving 70% inhibition of tritiated thymidine incorporation after 72 h in culture. Furthermore, calcitriol suppressed interleukin-2 (IL-2) production by PHA-stimulated peripheral blood mononuclear cells in a concentration-dependent fashion. Lastly, the suppressive effect of calcitriol on cellular proliferation was partially reversed by the addition of saturating amounts of purified IL-2. We conclude that calcitriol is a potent inhibitor of PHA-induced lymphocyte blast transformation and that this effect is mediated, in part, through suppression of IL-2 production. Thus, calcitriol appears to possess immunoregulatory properties that have been unappreciated heretofore.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Calcifediol / pharmacology
  • Calcitriol / pharmacology*
  • Humans
  • Immunosuppressive Agents / pharmacology*
  • Interleukin-2 / biosynthesis
  • Kinetics
  • Lymphocyte Activation / drug effects*
  • Phytohemagglutinins / pharmacology
  • T-Lymphocytes / immunology*


  • Immunosuppressive Agents
  • Interleukin-2
  • Phytohemagglutinins
  • Calcitriol
  • Calcifediol