SPECIFIC HIGH-AFFINITY RECEPTORS FOR 1,25-DIHYDROXYVITAMIN D3IN HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS: PRESENCE IN MONOCYTES AND INDUCTION IN T LYMPHOCYTES FOLLOWING ACTIVATION

Abstract

Human peripheral blood monocytes have high affinity binding sites for 1,25-(OH)₂D₃ (Kd 0.14 nM, sedimentation coefficient 3.7S). Resting human peripheral blood T lymphocytes, however, do not have a demonstrable 1,25-(OH)₂D₃ receptor. After activation with phytohemagglutinin the T cells exhibit the receptor within 24 h, and this expression is blocked by cycloheximide. The receptor in activated T lymphocytes has a sedimentation coefficient of 3.7S and a high affinity (Kd 0.10 nM) for the ligand.