[The morphological and functional integrity of cryo-preserved leukocytes]

Human peripheral blood lymphocytes were frozen by a simplified method which is described. Light and electron microscopic investigations of the frozen-thawed cells showed no significant morphological changes compared to the fresh cells; comparison of E-rosette formation and nonspecific acid esterase activity before and after cryoconservation afford evidence of a possible slight change in the percent relationship of T- and B-cells, whereas thymidine uptake values within normal range after stimulation with PHA and homologous cells demonstrate the functional integrity of the lymphocytes.