Studies of the Reticuloendothelial Mass and Sequestering Function of Rat Bone Marrow

Quantitative studies were made in rats of the total reticuloendothelial cellcontent of bone marrow and of the ability of marrow to sequester antibody-treated red cells, immature red cells and carbon particles. Although normalmarrow played a relatively minor role in clearing cells and particles from theblood stream, its clearing activity increased markedly when the marrow wasdepleted of its blood-forming cells. The greatly enhanced ability of hypoplasticmarrow to trap immature red cells suggests that this may be a homeostaticmechanism for repopulating the depleted marrow.

Carbon blockade resulted in decreased liver and spleen uptake of sensitizedred cells, but enhanced the marrow uptake. This suggests that marrowsequestration 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 actedin parallel with those of the liver and reciprocally with those of the spleen.

Submitted on July 17, 1964 Accepted on December 20, 1964