Cryopreservation of hemopoietic tissue aimed at reducing immunological reactivity

A method has been developed of decreasing immunologic activity of lymphocytes from spleen, lymph nodes, and bone marrow (freshly collected or frozen) with a high percentage of intact stem cells. In experiments in vivo on lethally irradiated mice, it was demonstrated that during combined transplantation to the recipients of preserved bone marrow from two genetically different donors, a rapid decrease or absence of the effect of inactivation of hemopoietic stem cells under the influence of allogeneic lymphocytes was observed in the mixed graft. When it is necessary to transplant large quantities of bone marrow from several genetically different donors, the use of cryopreserved bone marrow is preferable to freshly drawn marrow due to the higher proliferative activity and the decreased risk in the development of immunological reactions.