Erythroid Colony Growth in Vitro from Human Peripheral Blood Null Cells: Evidence for Regulation by T‐Lymphocytes and Monocytes

Abstract

Colony assays in methylcellulose of primitive erythroid precursors (BFU-E [erythropoietic burst-forming units]) were carried out from the null cell fraction of normal human peripheral blood lymphoid cells. There was little proliferation or maturation of BFU-E as assessed by the number and the size of colonies formed when null cells alone were cultured. Culture of null cells with up to 8 .times. 105 autologous T lymphocytes/ml led to considerable stimulation of colony growth and maturation. Culture of null cells with peripheral blood monocytes also resulted in the induction of BFU-E growth, although the response was inferior to that seen with T cells. Co-culture of null cells with T cells and monocytes resulted in a uniformly greater response than with either alone; this was due to a positive interaction between these 2 cell types.