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 differentiat ion of murine bone marrow and spleen cells was investigated in this st udy. 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 incre ase in the number of bone marrow and spleen CFUs. pGPL-Mc treatment, i n particular, increased the number of bone marrow and splenic CFU-GMs, CFU-Gs and CFU-Ms during and after three intraperitoneal administrati ons. The greatest myeloid stimulation of bone marrow CFU-GMs, CFU-Gs a nd CPU-Ms was observed between days 7 and 14, with maximal values on d ays 12 and 14. Highly significant stimulation of splenic CFU-GMs, CPU- Gs and CPU-Ms was observed between days 7 and 10 with maximal values o n day 10, while the initial stimulation of these progenitors was obser ved starting from day 1 in bone marrow and day 7 in spleen. These effe cts of pGPL-Mc were associated with an increase in granulocyte, monocy te and thrombocyte counts in the peripheral blood. Granulocyte and mon ocyte counts remained high up until day 12, while those of thrombocyte s were prolonged until day 18. May-Grunwald-Giemsastained colony sampl es and differential white blood cell counts demonstrated that the gran ulocyte population is composed almost entirely of neutrophils. pGPL-Mc is therefore a broad-spectrum haematopoietic growth factor with a hig hly promising application in the reversal of chemotherapy- and/or radi otherapy-induced myelosuppression.