[The transplantability of bone marrow and spleen cells after filtration through silon tissue]

Investigations were carried out on the separation of haematopoietic stem cells from suspensions of the bone-marrow and spleen by means of filtration with silon tissue. The presence of stem cells in the filtrates was determined by the spleen colony test according to the method of Till and McCulloch in irradiated mice. The investigations revealed that a selective separation of haematopoietic stem cells could not be achieved when proceeding in this way. From the results of further test series, in which suspensions were also used which had been gained from haematopoietic tissues of hypersplenic mice, the conclusion could be drawn that the haematopoietic stem cells obtained by filtrating the bone-marrow will have another affinity to the spleen tissue of irradiated mice than the haematopoietic stem cells gained by filtrating the spleen tissue.