Characterization of granulocytes and mast cells in cultures of mouse bone marrow stimulated with interleukin-3

Bone marrow cells in liquid culture with interleukin 3 produce a population of non-adherent granulocytes and mast cells. Flow cytometry was used to identify granulocytes and mast cells on the basis of the physical properties of perpendicular light scatter (PLS) and coulter volume (CV) as well as the expression lgE and CR3 receptors. Multicolor analysis indicated there were subpopulations of Thy 1.2 positive cells which transiently appeared in these cultures and also expressed lgE receptors, CR3 receptors or neither of these receptors. The data suggested a differentiation scheme in which Thy 1.2 positive precursor cells give rise to granulocytes and mast cells. Further evidence for this differentiation scheme was provided from CV vs. PLS distributions which showed increases in CV and PLS as Thy 1.2 positive cells differentiated into mast cells and decreases in CV and PLS as Thy 1.2 positive cells differentiated into granulocytes.