Evaluation of the clonogenic cell population (Leuk-CFU) in the marrow of BN rats during development of a promyelocytic leukemia (BNML): an in vitro assay.
We report a reproducible in vitro clonogenic assay for the transplantable BN rat promyelocytic leukemia (BNML). Colony growth required a feeder activity elaborated by normal rat marrow cells. This stimulating activity is ascribed to the stromal elements. The in vitro maintained BNML cell line IPC-81 [Lacaze et al., Leukemia Research 7, 145 (1983)] also exhibited stimulating activities at high cell concentrations, confirming the autocrine capacities previously described. The nature of the stimulating activity is unknown but it is probably not of CSF type, and is not transferred to culture supernatants. This in vitro clonal assay permits the quantification of the clonogenic cells present in leukemic marrow during the early stage of the disease, when BNML cells are not yet distinguishable morphologically. Leukemic Cell Forming Unit (L-CFU) response was linear; 5-10(3) clones can be scored reproducibly. The plating efficiency obtained with cultured IPC-81 cells was high (60-90%), whereas marrow transplanted leukemia cells had reduced clonogenic capacities. These results are discussed.
D000818:Animals; D001853:Bone Marrow / Q000473:pathology; D002455:Cell Division; D002999:Clone Cells / Q000473:pathology; D004195:Disease Models, Animal; D006098:Granulocytes / Q000473:pathology; D007700:Kinetics; D015470:Leukemia, Myeloid, Acute / Q000473:pathology*; D051381:Rats; D011914:Rats, Inbred BN