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Updated: May 2, 2026
A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity
Published on: August 9, 2017
A high-throughput assay of NK cell activity in whole blood and its clinical application
Saet-byul Lee1, Junhoe Cha2, Im-kyung Kim3
1Department of Microbiology and Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Republic of Korea.
Abstract:
Natural killer (NK) cells are lymphocytes of the innate immune system and have the ability to kill tumor cells and virus-infected cells without prior sensitization. Malignant tumors and viruses have developed, however, strategies to suppress NK cells to escape from their responses. Thus, the evaluation of NK cell activity (NKA) could be invaluable to estimate the status and the outcome of cancers, viral infections, and immune-mediated diseases. Established methods that measure NKA, such as (51)Cr release assay and CD107a degranulation assay, may be used to determine NK cell function, but they are complicated and time-consuming because they require isolation of peripheral blood mononuclear cells (PBMC) or NK cells. In some cases these assays require hazardous material such as radioactive isotopes. To overcome these difficulties, we developed a simple assay that uses whole blood instead of PBMC or isolated NK cells. This novel assay is suitable for high-throughput screening and the monitoring of diseases, because it employs serum of ex vivo stimulated whole blood to detect interferon (IFN)-γ secreted from NK cells as an indicator of NKA. After the stimulation of NK cells, the determination of IFNγ concentration in serum samples by enzyme-linked immunosorbent assay (ELISA) provided a swift, uncomplicated, and high-throughput assay of NKA ex vivo. The NKA results microsatellite stable (MSS) colorectal cancer patients was showed significantly lower NKA, 263.6 ± 54.5 pg/mL compared with healthy subjects, 867.5 ± 50.2 pg/mL (p value <0.0001). Therefore, the NKA could be utilized as a supportive diagnostic marker for microsatellite stable (MSS) colorectal cancer.
Insights
A new, simple whole-blood assay measures natural killer (NK) cell activity (NKA) by detecting interferon-gamma. This method is faster and easier than traditional assays and can help diagnose diseases like colorectal cancer.
Area of Science:
- Immunology
- Oncology
Background:
- Natural killer (NK) cells are crucial for innate immunity against tumors and viruses.
- Tumors and viruses employ strategies to evade NK cell responses.
- Assessing NK cell activity (NKA) is vital for monitoring cancers, viral infections, and immune diseases.
Purpose of the Study:
- To develop a simplified, high-throughput assay for measuring NK cell activity (NKA).
- To establish a reliable method for NKA assessment using whole blood, avoiding complex cell isolation procedures.
Main Methods:
- A novel assay utilizing whole blood, bypassing the need for peripheral blood mononuclear cell (PBMC) or NK cell isolation.
- Detection of interferon-gamma (IFN-γ) in serum from ex vivo stimulated whole blood as a marker of NKA.
- Enzyme-linked immunosorbent assay (ELISA) for quantifying IFN-γ concentration.
Main Results:
- The developed assay is swift, uncomplicated, and suitable for high-throughput screening.
- Significantly lower NKA was observed in microsatellite stable (MSS) colorectal cancer patients (263.6 ± 54.5 pg/mL) compared to healthy subjects (867.5 ± 50.2 pg/mL).
- A p-value <0.0001 indicates a statistically significant difference in NKA between the groups.
Conclusions:
- The novel whole-blood assay provides a practical and efficient method for assessing NKA.
- NKA measurement holds potential as a supportive diagnostic marker for microsatellite stable (MSS) colorectal cancer.
