In the world of immunotherapies, most treatments aim to activate T cells that target tumor cells, but an increasing number of natural killer (NK) cell-based therapies are emerging. NK cells are part of the innate immune system and can recognize and eradicate cancer cells, but deciphering these important cells requires understanding them at a single-cell level. Our experts Guido Stadler, Ph.D., Staff Scientist; Maryam Shansab, Ph.D., Senior Scientist; and Natalie Marks, M.Sc., Staff Scientist provide some insight into these complex cells.

Why are nk cells challenging to work with?

NK cells are complex lymphocytes and their function isn’t easily understood at a single-cell level. This lack of insight makes it difficult to develop immunotherapies that effectively harness the full potential of these potent killers. Since these cells are so complex, it’s tricky to get the whole picture of NK cells using traditional evaluative methods, which rely on bulk measurements of these heterogeneous cell samples.

how does the nk cell cytotoxicity assay help?

With the Cytotoxicity Assay, part of the Opto™ Cell Therapy Development workflow, you can gain a deeper understanding of what NK cells secrete, identify cell surface markers, and measure the rate of target cell killing. After we gain this knowledge of cells on-chip, the NK cells with potent cytotoxicity can be recovered for downstream analysis.

expert tips

Only load the live cells by utilizing Annexin V-based target penning and selection (TPS). This allows for a cleaner analysis (use BLI Loading Reagent for best results as well!)

Use negative controls — always have cells that shouldn’t be targeted by NK cells on the same chip

Use TPS with cell surface markers to selectively load pure NK cell populations and remove unwanted cells from the assay

Use fluidic shifts and TPS penning to maximize the amount of NK cells for screening

Compare different NK cell treatments on the same chip

show me an example!

In the example shown here, we directly measure NK-mediated cell killing using the Cytotoxicity Assay.

show me more data…

Read our Unravel the Complexity of Single Natural Killer Cell Cytotoxicity and ADCC Mediation application note to see the entire data set, including mapping single NK cell killing kinetics.

This story originally appeared in the Winter 2020/21 edition of BLI News. To read more, check out the latest edition.