Abstract
Quantitative studies were made in rats of the total reticuloendothelial cell content of bone marrow and of the ability of marrow to sequester antibody-treated red cells, immature red cells and carbon particles. Although normal marrow played a relatively minor role in clearing cells and particles from the blood stream, its clearing activity increased markedly when the marrow was depleted of its blood-forming cells. The greatly enhanced ability of hypoplastic marrow to trap immature red cells suggests that this may be a homeostatic mechanism for repopulating the depleted marrow.
Carbon blockade resulted in decreased liver and spleen uptake of sensitized red cells, but enhanced the marrow uptake. This suggests that marrow sequestration of cells, in contrast to that in the liver and spleen sequestration, is not affected by phagocytic activity.
In their functions and reactions the RE cells of the marrow usually acted in parallel with those of the liver and reciprocally with those of the spleen.
