Stimulation of myelopoiesis in Lister a monocytogenes-infected mice by an aggregated polymer isolated from Asp ergillus oryzae

In this work, we investigated the effects of the proteic aggregated polymer of magnesium ammonium phospholi-noleate-palmitoleate anhydride (MAPA) isolated from Aspergillus oryzae on the growth and differentiation ofbone marrow granulocyte-macrophage progenitor cells (CFU-GM) inListeriamonocytogenes-infectedmice.Asignificant reduction in the CFU-GM numberwas observed in the initial phase of infection with a sublethal dose of Listeria. Treatment of mice with 0.5, 2.0 and 5.0 mg/kg MAPA for 7 days prior to infection significantly stimulated myelopoiesis in a dose-dependent manner. Moreover, treatment with 0.5 and 5.0 mg/kg MAPA resulted in 30%/6 and 40% cures of mice lethally infected with Listeria, respectively. MAPA added directly to the culture dishes hardly affected colony formation by bone marrow cells, suggesting an indirect effect ofthis compound on myelopoiesis in vivo. In summary, the data show that MAPA can modulate the CFU-GM generation and antibacterial resistance in listeriosis. As the ability of hematopoietic tissues to produce phagocytes is of particular significance to mediate resistance to Listeria, the promotion ofbone marrow CFU-GM by MAPA may contribute to a rapid restoration of phagocyte numbers in infected sites, thus mitigating the course of infection.