CD133, also known as Prominin, was first described as a cell surface marker recognized by monoclonal antibody AC133 on putative hematopoietic stem cells. CD133 positive fraction of human bone marrow, cord blood and peripheral blood have been shown to efficiently engraft in xenotransplantation models, and have been shown to contain the majority of the granulocyte/macrophage precursors, NOD/SCID repopulating cells and CD34+ dendritic cell precursors.