Lymphocyte surface markers and cytotoxicity following cryopreservation.

The effects of cryopreservation (CP) on lymphocyte subpopulation distribution and functional activity in blastogenic and cytotoxicity assays were tested. Peripheral blood lymphocytes (PBL) from 12 healthy human donors were obtained by Ficoll-Hypaque separation. Half of each sample was tested fresh, while the other half was cryopreserved and then thawed and tested the same day. Each sample of CP-PBL was compared to fresh PBL from the same donor in simultaneous assays. Following CP there was a significant reduction in the percentage of E, EA gamma, and EA mu rosette-forming cells with a reciprocal increase in EAC rosette-forming cells. The blastogenic response to alloantigens was stable following CP while blastogenesis in unstimulated control cultures was significantly reduced. Mixed lymphocyte culture (MLC)-induced cell-mediated lympholysis (CML) was consistently and significantly diminished by CP. Cytotoxicity in 4 h chromium release NK (K562), ADCC, and LDCC assays was also significantly diminished by CP. In contrast, cytotoxicity was unaffected in an 18 h cytotoxicity assay against adherent cultured melanoma target cells.