Effects of polar glycopeptidolipids of Mycobacterium chelonae (pGPL-Mc) on granulomacrophage progenitors

Effects of polar glycopeptidolipids of Mycobacterium chelonae (pGPL-Mc) in the in vivo stimulation of haematopoietic growth and differentiation of murine bone marrow and spleen cells was investigated in this study. Progenitors were determined with a quantitative cultural analysis of bone marrow and spleen cells in methylcellulose using rmGM-CSF and rmIL3. Injection of pGPL-Mc produced a significant time-related increase in the number of bone marrow and spleen CFUs. pGPL-Mc treatment, in particular, increased the number of bone marrow and splenic CFU-GMs, CFU-Gs and CFU-Ms during and after three intraperitoneal administrations. The greatest myeloid stimulation of bone marrow CFU-GMs, CFUGs and CFU-Ms was observed between days 7 and 14, with maximal values on days 12 and 14. Highly significant stimulation of splenic CFU-GMs, CFU-Gs and CFU-Ms was observed between days 7 and 10 with maximal values on day 10, while the initial stimulation of these progenitors was observed starting from day 1 in bone marrow and day 7 in spleen. These effects of pGPL-Mc were associated with an increase in granulocyte, monocyte and thrombocyte counts in the peripheral blood. Granulocyte and monocyte counts remained high up until day 12, while those of thrombocytes were prolonged until day 18. May-Grünwald-Giemsa-stained colony samples and differential white blood cell counts demonstrated that the granulocyte population is composed almost entirely of neutrophils. pGPL-Mc is therefore a broad-spectrum haematopoietic growth factor with a highly promising application in the reversal of chemotherapy- and/or radiotherapy-induced myelo-suppression.