Effect of Bone Marrow Culture In Vitro on Its Protective Action in Irradiated Mice2

Abstract

Mouse bone marrow cells tissue-cultured in a special container have been studied in an attempt to identify the cells responsible for the protection afforded recipient, lethally irradiated mice, by bone marrow post treatment. After 4 days of culture, a decreased protective activity of injected tissue-cultured cells was observed. By the 9th day of life in vitro, the explanted bone marrow cells had essentially lost their protective capacity. Analysis of the cell species present at this time showed that several stem-cell types persisted in such negative cultures. These findings are discussed in relation to the mechanism of protection of recipient mice, with bone marrow.