Proliferative history and hematopoietic function of ex vivo expanded human CD34+ cells

becomes an important consideration and what components of the immune response play an important role. It is clear from animal studies in sheep 1,2 and mice 3 that engraftment can occur across full allogeneic or xenogeneic 4 barriers if transplantation is performed early enough in gestation. In studies that we have presented (manuscripts in preparation or submission), Thus if the transplant is performed early enough in gestation and there is adequate antigen presentation in the thymus, it appears that T-cell mediated alloreactivity is not prohibitive to engraftment.