About Natural Killer (NK) Cells


Natural killer (NK) cells are important effector cells in combating viral infections and neoplasms. Their cytotoxic activity is controlled by multiple receptors that recognize MHC class I antigens. Cells that lack the appropriate MHC class I are lysed because the inhibitory receptor is not engaged.

While we only have negatively selected NK cells in stock, we can provide positively selected NK cells upon request. The positively selected population includes CD3+ CD56+ cells that are eliminated in the negative selection process.

For further information on NK cells, see the cytotoxic activity shown below using frozen NK cells and review the NK articles listed at the bottom of this page.

Cytotoxic Activity of NK Cells

Natural Killer (NK) Cells AssayThese histograms depict the in vitro lytic activity of NK cells from lot 3100MA16. K562 target cells were labeled with carboxyfluorescein succinimidyl ester (CFSE) to distinguish them from the effector NK cells. NK cells were thawed and added to the target cells at the indicated ratios. The co-cultures were incubated for 18 hours at 37°C, 5% CO2. Cells were then washed once and 7-AAD was added to label the dead cells. In this experiment, lysis was evident at all ratios with maximum cell killing observed at a 10:1 NK:K562 ratio.

NK Cell Review Articles

Natural killer cells: integrating diversity with function. Immunology. 2009

Recognition of infected cells by natural killer cells. Current Opinion in Immunology. 2004.

Activating receptors and coreceptors involved in human natural killer cell-mediated cytolysis. Annual Review of Immunology. 2001.

Our apologies to the many contributors to this field who are not listed here.