Immunological evidence for murine hematopoietic stem cell subpopulations differing in self-renewal capacity

The present study provides evidence for a correlation between the brain-associated stem cell antigen and the self-renewal capacity of pluripotent hematopoietic stem cells (spleen colony-forming units). A minor subpopulation of spleen colony-forming units which does not express the antigen exhibited a 3- to 4-fold greater self-renewal capacity while proliferating in both bone marrow and spleen compared to stem cells which express the antigen. This finding supports the 'generation-age' hypothesis for stem cell differentiation; according to this hypothesis, hematopoietic cells derive from a population of young stem cells which lack the antigen, exhibit a high self-renewal capacity, and are quiescent in cell cycle.