Changes in stem cell compartments in CBA mice after treatment by serum obtained from leucophoretic rats

Leucophoretic rat serum (LS) obtained from rats previously treated by i.p. injection of polyvinylpyrrolidone (PVP), specifically stimulates proliferation of morphologically recognizable granulocytic cells in vivo. In this work the effect of the same serum on CFU-c and CFU-s was studied. It was demonstrated that a single injection of LS induced firstly (after 12 hr) an increase in CFU-c and afterwards, at 24 and 48 hr, increase in CFU-s. It was therefore concluded that the humoral factor present in LS, stimulating primarily the proliferating granulocytic cell compartment, has some effect on CFU-c, while the effect on the CFU-s cell compartment is secondary to the changes in more mature cell compartments.