METHODS FOR SELECTIVELY EXPANDING STEM CELLS

摘要

Methods are provide for increasing the number of human hematopoietic precurs or cells in vitro, comprising the general steps of (a) separating CD34-positive human hematopoietic precursor cells from CD34-negative cells present in a blood product; (b) inoculating the separated precursor cells at an initial density of between 1.times.10 3 cells/ml and 4.times. 10 6 cells/ml into a culture vessel containing a cultu re medium comprising a nutritive medium and hematopoietic growth factors effective for expansion of CD34-positive cells, with the proviso that said culture medium and cultur e vessel contain no stromal cells or stromal cell conditioned medium; and (c) culturi ng the precursor cells under conditions and for a time sufficient to increase the number of precursor cells relative to the number of precursor cells present after separation of hematopoietic cells from said blood product.