Natural killer (NK) cells play a key role in the innate immune system. These effector lymphocytes react to certain infections and malignancies by directly destroying infected or transformed cells and by secretion of potent immune system cytokines that stimulate and guide other white blood cells to the target area. NK cells have the ability to recognize foreign or stressed cells that lack antibodies or major histocompatibility complex (MHC) class I proteins on the surface. If not restrained by inhibitory receptors recognizing MHC class I proteins on the surface of self-cells, NK cells are able to kill normal, healthy cells.

Human cord blood CD56+ NK cells are positively selected using immunomagnetic anti-CD56 microbeads from the mononuclear cell fraction. Isolated cells are characterized by flow cytometry prior to cryopreservation to ensure a highly pure and viable cell population.

Cells were obtained using Institutional Review Board (IRB) approved consent forms and protocols.