Effect of Granulocytic Chalone on Acute Myeloid Leukæmia in Man

Humoral Factors Modulating Growth of Granulocyte Macrophage Progenitor Cells

“…Low molec ular PMN-derived inhibitors have been de scribed [1,15,16,24] which, cell line-spe cific but not species-specific, inhibit cell proliferation in the granulocyte/macrophage system in a reversible manner. This sub stance called granulocyte chalone is a poly peptide with a molecular weight of about 4,000 daltons, which most likely arrests the CFU-C compartment in the G, phase.…”

“…As in other tissues, a cell line-specific but not spe cies-specific inhibitor called chalone has been described [18]. Its inhibitory activity has been shown in the culture system [15,16] and perhaps in vivo [24] and it was pos tulated that it might be a granulocyte prod uct. The subcellular origin of this granulo cyte product is unknown.…”

Methods for the Preparation of Purified Granulopoiesis-Inhibiting Factor (Chalone)

“…The factor suppresses myelopoiesis in vitro and in addition has complex effects on hemopoiesis in vivo, mainly expressed as a reduction in the numbers of stem cells committed for myelopoiesis (the authors, in preparation). Analogous biological effects of similar preparations of varying degrees of purity have been described by several other laboratories [8][9][10][11][12][13][14] In this paper emphasis is laid on purification methodology and not so much on assay methods and the examples given merely serve as illustrations. We hope that the chemical methods described here will provide those with a mainly biological interest in chalone-like ganulopoietic inhibitors with preparations whose quality correlates with their intended biological experi-…”

Spontaneous death of rat chloroleukaemia cells induced by an endogenous growth inhibitor

“…40 Finally, some de novo insertions of LINE in neuronal progenitor cells may induce apoptosis, and they may be responsible for the massive cell death that occurs during neurodevelopment. 41 Considering these findings, the observed rapid regression of leukaemic cell populations in human patients treated with a semi-purified inhibitor 16,42,43 may be associated with LINE-induced cell death, and the rate of leukaemic cell death increases after the onset of inhibitor treatment. For instance, the total leukaemic mass was reduced by an estimated 3 kg in 2 weeks in one patient.…”

“…In general, the rate of leukaemic cell count reduction is similar to that observed after conventional drug therapy. 42 At the time of that study, 42 the immune system was suggested to play a leading role in the eradication of leukaemic cells,…”