DEVELOPMENT OF RAT MAST-CELLS INVITRO .1. DIFFERENTIATION OF MAST-CELLS FROM THYMUS-CELLS

Abstract

Mast cells were differentiated by long-term culture of rat thymus cells on rat fibroblast monolayers. Mature mast cells obtained in the culture were morphologically similar to normal peritoneal and thoracic mast cells and possessed specific receptors for Ig [immunoglobulin] E on their surface. In culture, blast cells appeared on the monolayer several days after seeding of thymus cells. These cells developed into young mast cells in the monolayer and became free in the culture medium with maturation. Receptors for IgE were detected on the surface of mastoblasts which contained a small amount of metachromatic granules. The number and/or affinity of the receptors for IgE increases with maturation of mast cells. Some mast cells differentiated from monolayers of embryo cells without seeding thymus cells. Mast cells can be differentiated from thymus cell culture without a monolayer. Thymus and embryo tissues probably contain precursors of mast cells.