Differentiation of subpopulations of human and murine hemopoietic stem cells by hypotonic lysis.

Both human and mouse bone marrow contain subpopulations of hemopoietic stem cells that greatly vary in their resistance to water exposure: The cells forming erythroid colonies or bursts in methyl cellulose in vitro are most sensitive to hypotonic conditions and are destroyed within 60 s in the hypotonic milieu. The murine pluripotent stem cells assayed by the spleen colony technique, as well as both murine and human myeloid stem cells assayed by the plasma clot diffusion chamber technique, displayed intermediate sensitivity and were nearly completely eliminated by 120 s of exposure to water. Both human and mouse bone marrow stem cells producing myeloid colonies in agar are most resistant to hypotonic conditions. The addition of monocyte-macrophages and lymphoid cells to water-exposed mouse bone marrow cell populations to compensate for losses did not restore either erythroid or myeloid colony formation.