Hematopoietic and mesenchymal progenitors in IL-5trg bone marrow.
(A) Bone marrow, spleen, and peripheral blood cells were harvested from IL-5trg and WT mice (n = 5) and assayed for numbers of LTC-ICs in the limiting dilution assay in 3 independent experiments. Adherent layers from IL-5trg and WT LTBMCs (n = 3) were harvested after 4 weeks of culture and assayed for numbers of LTC-ICs. The LTC-IC frequency in the bone marrow (per 106 bone marrow cells), blood (per 1 mL), spleen (per whole organ), and LTBMC (per whole culture) from one representative experiment is shown as mean ± SD. (B) Bone marrow cell suspensions from IL-5trg and WT mice were plated into methylcellulose cultures in the presence of lineage-specific cytokines. GM-CSF or M-CSF was added to estimate numbers of granulocyte-macrophage– or macrophage-CFCs, and IL-5 (50 ng/mL) or IL-7 was added to estimate the numbers of eosinophil or B-lymphoid progenitors (*P < .01). Colonies were cultured in quadruples, calculated after 7 days of culture, and expressed as mean ± SD. (C) Bone marrow or spleen cells from IL-5trg and WT mice were cultured in Dexter media for 7 days (n = 3). Number of stromal cell colonies (CFU-Fs) was calculated under the microscope and expressed as mean ± SD of the number of CFU-F/whole spleen or femur for bone marrow. (D) Bone marrow cells harvested from IL-5trg and WT mice were plated on a 75% confluent layer of bone marrow-derived stromal cells. Half of the culture medium was harvested from the cultures at each feeding, and the number of nonadherent cells was calculated and expressed as mean ± SD.
