Long-term bone marrow culture systems: normal and cyclic hematopoietic dogs.

A continuous long-term liquid culture in both a micro and macro system that incorporates bone marrow cells from normal and cyclic hematopoietic dogs is described. An adherent layer composed of fibroblasts, endothelial cells, mononuclear phagocytic cells, and fat-containing cells is essential for continuous hematopoiesis. Hematopoiesis was measured by the recovery of the nonadherent cells and the generation of committed granulocyte-monocyte progenitor cells for a period of seven weeks. Optimum growth factors include the use of horse serum, fetal bovine serum, dog serum, hydrocortisone, a 33 degrees C incubation temperature and feeding twice a week. As is true for both human and murine marrow liquid cultures, horse serum and hydrocortisone are essential for development and maintenance of fat-containing cells in the described systems. Both factors are important in hematopoiesis but their respective roles have not been defined. Normal and cyclic hematopoietic dogs bone marrow cells are comparable in their ability to establish long-term cultures. The micro-method (Linbro-well culture) gave similar results in maintaining hematopoiesis as did a macromethod (flask culture).