Figure 3

Viability of PBMC 24 hours after thawing from liquid nitrogen. After whole blood was incubated at different temperatures for varying lengths of time, PBMC were isolated and cryopreserved. Samples were thawed and rested overnight at 37°C before staining with CD4, CD8, Annexin V and 7-AAD. The viable populations were defined as Annexin V negative and 7AAD negative and are expressed as a percentage of the respective populations of (A) PBMC, (B) CD8 and (C) CD4 lymphocytes. Shaded area on graph represents the control condition of incubating whole blood at 22°C for 24 hours to which all other conditions were compared. (*) p = 0.003; (**) p = 0.03.