Modulation by serum from irradiated and marrow transplanted mice of hemopoietic regeneration in mouse spleen organ cultures.

A spleen organ culture system has been used to analyse hemopoietic progenitor cell (CFC) regeneration in the C57BL mouse spleen following 800 rad whole-body irradiation and the injection of 10(7) syngeneic bone marrow cells. The linear regeneration pattern observed in vitro compared to an initial decrease followed by a rapid increase in CFC levels in vivo suggested a possible modulating influence of humoral factors in vivo on hemopoietic regeneration in the spleen. In agreement with this, addition of mouse serum collected at various time intervals after irradiation and transplantation to spleen organ cultures in vitro was able to reproduce accurately the kinetics of CFC regeneration seen in spleens in vivo. In addition the possible role played by colony stimulating factors (CSF) in the regulation of CFC regeneration in spleen organ cultures was investigated. No clear evidence was found for the importance of CSF in regulating the CFC regeneration in organ cultured spleens.