Natural killer (NK) cells are lymphocytes of the immune system. This particular NK population is derived from umbilical cord blood.
Umbilical cord blood (UCB) is obtained by cannulation of the umbilical vein and collection into a bag containing citrate-phosphate-dextrose and processing by red blood cell depletion using Hetastarch, followed by volume reduction. The sample is then washed with RPMI 1640 (without phenol red) containing fetal bovine serum (FBS; 5% v/v). Cell pellets are then resuspended at 5x107 cells/ml in RoboSep buffer. DNase I (0.1mg/ml solution) is added to the cell suspension to a final concentration of 100μl/ml, mixed gently by pipetting and incubated for 15min at room temperature (RT) prior to isolation of NK cells using the EasySep® NK Cell Enrichment Kit. Human NK Cell Enrichment Cocktail (containing monoclonal antibodies to human cell surface antigens CD3, CD4, CD14, CD19, CD20, CD36, CD66b, CD123, HLA-DR, and glycophorin A) is added to the cell suspension at a final concentration of 50μl/ml and incubated for 10min at RT. After incubation with EasySep® Magnetic Microparticles (final concentration of 100μl/ml) for 5min at RT, enrichment of NK cells is performed according to the protocol provided by the manufacturer. A CD56+CD3− population is collected and ready for further analysis or cultivation.