Effect of Macrophage Colony-Stimulating Factor (M-CSF) on Mouse Immune Responses in Vivo

AbstractWe examined the effects of recombinant human M-CSF (rhM-CSF) on mouse macrophages and immune responses in vivo. Intraperitoneal administration of rhM-CSF (20–500 μg/ml) increased Mac-l+ cell numbers in the peritoneal cavity. The tumoricidal activities of the macrophages from vehicle-administered (V-MΦ) and from rhM-CSF-administered (M-MΦ) mice were the same as those observed in vitro. However, when activated by lipopolysaccharide (LPS), the tumoricidal activity of M-MΦ was stronger than that of V-MΦ. Intravenous administration of rhM-CSF (500 μ g/gk) increased the number of spleen cells. Flow cytometric analysis showed that administration of rhM-CSF increased Mac-1+, B220+ and NK 1.1+ cell counts in the spleen. However, CD4+ and CD8+ cell numbers did not change. Concomitant increases were observed in levels of IL-4 and IL-10 in mouse serum following rhM-CSF administration, but no significant changes were observed in the serum level of IFN-γ.In experiments involving mouse immune responses, the admi...