In vivo stimulation and inhibition of granulopoiesis: the effect of an inflammatory reaction on murine diffusion chamber granulopoiesis

Humoral factors influencing granulopoiesis have been evaluated using diffusion chambers (DC) implanted in the peritoneal cavity of mice challenged by an aseptic abscess produced by the subcutaneous implantation of copper rods. This resulted in an increase in peripheral blood neutrophils and an increase in tibial granulocytic elements. When DC loaded with bone-marrow cells were implanted into mice stimulated the day before by an aseptic abscess significantly more CFU-s, CFU-c, proliferative and non-proliferative granulocytes were produced, as compared to DC implanted into control hosts. When DC were implanted 4-6 d after the induction of inflammation in mice a significant depression of DC granulopoiesis was observed. Levels of serum and DC fluid CSF and serum inhibitors of in vitro colony growth showed no correlation with DC myelopoiesis. The data show that mice undergoing an inflammatory reaction elaborate first humoral substance(s) enhancing CFU-s and granulocytic growth in DC and next inhibitory factor(s) of DC granulopoiesis.