[Ultrastructure of the lymphocytes in lymphoid organs following cryopreservation with PEO-400 protection].

Electron microscopic examination of lymphocytes after cryopreservation with PEO-400 used as a cryoprotectant has shown that changes in the cytoplasmic membrane structures are of reversible character after thawing. Programmed freezing with a period of temperature holding is beneficial for lymphocyte cryopreservation.