CFU-S in individual erythroid colonies derived in vitro from adult mouse marrow

Abstract

IT is generally accepted that in the haematopoietic system there is a hierarchy of pluripotent and committed progenitor cell types. Representative committed progenitors from all the myeloid and lymphoid pathways can be detected by in vitro colony assays¹. This methodology has been extended to include multipotent haematopoietic progenitors^2–5, and it has since been shown that at least one such multipotent cell type, the progenitor of macroscopic erythroid-megakaryocyte bursts, undergoes self-renewal during colony formation in vitro⁵. We now report that cells capable of macroscopic spleen colony formation (CFU-S)⁶ are present in macroscopic bursts and that on average two to three and up to five self-renewal divisions of CFU-S can occur during the first 9 d of burst growth. These findings raise the possibility that clonal analysis techniques⁷ may be combined with cell culture manipulations to investigate how the choice between self-renewal and progressive differentiation is determined.