In vitro maintenance of hemopoietic stem cells with lymphoid and myeloid repopulating ability by a cloned murine adherent bone marrow cell line.

Colonies containing blast cells (greater than 95%) have been characterized in 14-day cultures of normal murine bone marrow or spleen cells, stimulated by an adherent bone marrow cell line, B.Ad. These blast cell colonies occurred at a frequency of 1-2 per 2.5 X 10(4) bone marrow or 2.5 X 10(5) spleen cells and contained from 0.7 to 14.7 X 10(4) cells. Assay of individual blast cell colonies showed that they contained day 8 and day 13 colony-forming units-spleen (CFU-S) and from 11 to 10,434 in vitro CFC. Chromosomally marked blast colony cells were transplanted into lethally irradiated recipients and shown to produce both myeloid and lymphoid progeny in the recipients' bone marrow, spleen, mesenteric lymph node, and thymus.