Preparation of colony stimulating factors from human placental conditioned medium

Abstract

Human placental conditioned medium is able to stimulate human bone marrow cells to form neutrophilic granulocyte-monocyte colonies and eosinophil colonies in agar cultures. Methods are described for preparing highly active preparations (capable of supramaximal stimulation of colony formation) by partial purification of the conditioned medium using calcium phosphate absorption and gel filtration chromatography. Partially purified calcium phosphate gel eluates appear to increase in specific activity after concentration by ultrafiltration. This phenomenon was not observed with the active fractions after further purification on Sephadex G-100. Fractionation of the conditioned medium using gel fi..