Analysis of purified fetal liver hemopoietic progenitor cells in liquid culture

Abstract

The action of different types of colony‐stimulating factors (CSFs) on purified fetal hemopoietic progenitor cells in liquid cultures was studied. Three types of CSF were examined–pregnant mouse uterus extract (PMUE), which contains macrophage CSF; mouse lung conditioned medium (MLCM), which contains granulocyte‐macrophage CSF; and pokeweed mitogen‐stimulated spleen cell‐conditioned medium (PWM‐SCM), which contains ganulocyte‐macrophage, eosinophil, megakaryocyte, and erythroid CSFs. Without a source of CSF, the cells died within 48 hr, but with CSF, cells entered an exponential growth phase within 18 hr with a doubling time of about 12 hr. Althogh growth was best with PWM‐SCM, this appeared ..