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Macrophage precursors originate from and undergo lineage commitment within designated sites of hematopoiesis, such as the mammalian bone marrow. These cells subsequently differentiate in response to stimulation with macrophage colony-stimulating factor-1 (CSF-1). The amphibian bone marrow, unlike that of mammals, has been overlooked as a source of leukocyte precursors in favor of the liver subcapsular region, where hematopoiesis occurs in anurans. Here we report that the bone marrow rather than the liver periphery provides macrophage progenitors to the amphibian Xenopus laevis. We identified the amphibian CSF-1, examined its gene expression in developing and virally infected X. lae vis and produced it in recombinant form (rXlCSF-1). This rXlCSF-1 did not bind or elicit proliferation/differentiation of subcapsular liver cells. Surprisingly, a subpopulation of bone marrow cells engaged this growth factor and formed rXlCSF-1 concentration-dependent colonies in semisolid medium. Furthermore, rXlCSF-1-treated bone marrow (but not liver) cultures comprised of cells with characteristic macrophage morphology and high gene expression of the macrophage marker CSF-1 receptor. Together, our findings indicate that in contrast to all other vertebrates studied to date, committed Xenopus macrophage precursor populations are not present at the central site of hematopoiesis, but reside in the bone marrow., (Copyright © 2013 S. Karger AG, Basel.)

Effects of Phytolacca acinosa polysaccharides I (PAP-I), 5 approximately 40 mg/kg in timing of 7 times/wk, 3 times/wk and 1 time/wk on their antitumor efficiency in Sarcoma-180 bearing mice were comparatively investigated. The results confirmed that PAP-I (10 mg/kg, 3 times/wk) reached its optimal antitumor efficiency. Concanavalin A-, lipopolysaccharides-induced lymphocyte proliferation and the IL-2 production were tested in normal mice which were treated with PAP-I, 5 approximately 50 mg/kg in timing of 1 time/wk and 3 times/wk. The results showed that PAP-I could augment lymphocyte proliferation and IL-2 production in the group treated with PAP-I in timing of once a week. However, in the group 3 times/wk, PAP-I could significantly weaken lymphocyte proliferation and IL-2 production. Further studies on IL-1, TNF and IL-6 secreted from macrophages and the level of CSF activity in serum of normal mice with different schedules showed that PAP-I (10 mg/kg, 3 time/wk) was the best one in regulating the production of IL-1, TNF, IL-6 and CSF activity. M-CSF was confirmed in the serum by using monoclonal antibody of IL-3, GM-CSF and polyclonal antibody of M-CSF. These results suggested that the antitumor effect of PAP-I, may be mainly related to its augmenting effect on macrophages in mice.