Fig. 6

Whole blood was collected in sodium heparin tubes and stored at room temperature until processed. Samples were processed on Day 1 (within 24 h of collection), Day 2 (within 48 h of collection) and Day 3 (within 72 h of collection), by both red cell lysis (RCL) of the whole blood and density gradient centrifugation (DGC). The processed samples were stored in cryomedia, containing foetal bovine serum (FBS) and dimethyl sulfoxide (DMSO), at − 80 °C