Survival and proliferation of hematopoietic progenitors (MNCs) in Rab-9 cocultures.

(A) Growth curves of nonadherent hematopoietic cells in Rab-9/LXSN, Rab-9/LMJSN, and Rab-9/LECDSN cocultures. In each well, 3 × 10⁵ MNC was cocultured with Rab-9 cells in DMEM/10% FCS in 12-well plates and subcultured at 1:2 to 1:4 ratios every 3 to 4 days. No exogenous hematopoietic growth factors were added. Cell numbers have been corrected for subculture ratios and shown on a logarithmic scale (eg, 3 = 10³ and 4 = 10⁴). Open circle, LXSN; filled circle, LMJSN; open square, LECDSN; 1 of 4 similar experiments. Each point represents the mean of duplicate measurements. (B) Results of colony assays performed on nonadherent cells recovered from cocultures on days 8, 16, and 21. Cells were plated in methylcellulose culture medium supplemented with SCF, IL-3, and GM-CSF. Data are expressed as the ratios of total CFC (HPP-CFC, CFU-GM, CFU-G, and CFU-M combined) recovered from Rab-9/LMJSN or Rab-9/LCEDSN cocultures to those recovered from Rab-9/LXSN cocultures. At each assay point, the total number of CFC recovered from Rab-9/LXSN coculture is treated as 1. Results are means of triplicates.