title: Quantification of prothymocytes in long-term bone marrow cultures.
abstract: Prothymocytes were present in long-term marrow cell cultures for 17 weeks, although at very low levels. The prothymocytes from the cultures appeared normal in their thymus repopulation ability since the growth curves for thymocytes derived from cultured cells, measured in thymuses of irradiated mice, were parallel to those for thymocytes derived from fresh bone marrow prothymocytes. The buoyant density distribution for prothymocytes from the cultures appeared normal as well, with a modal density of 1,069 g/cm3. The prothymocyte density profile was similar to that for CFUS from the cultures which had a modal density of 1.070 g/cm3. Prothymocytes were lost from culture before CFUS and a decreased ratio of prothymocytes to CFUS was evident within the first 24 hours of culture. The kinetic differences between prothymocytes and CFUS in vitro suggest that these two functional assays detect different cells.
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002453:Cell Cycle; D002454:Cell Differentiation; D002469:Cell Separation; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient; D003114:Colony-Forming Units Assay; D006412:Hematopoietic Stem Cells / Q000166:cytology; D008297:Male; D051379:Mice; D008806:Mice, Inbred AKR; D008809:Mice, Inbred C3H; D013601:T-Lymphocytes / Q000166:cytology*; D013997:Time Factors