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A Flow Cytometry-Based Cytotoxicity Assay for the Assessment of Human NK Cell Activity
Published on: August 9, 2017
NK cell assays in immunotoxicity testing
Abstract:
It is well known that natural killer (NK) cells are involved in defense against viruses and some tumors. NK cells kill target cells by the directed release of cytolytic granules that contain perforin, granzymes, and granulysin. It is increasingly important to evaluate NK cell function in immunotoxicity testing. NK cell function can be evaluated by determining cytolytic activity against target tumor cells by the (51)Cr-release assay and also by determining the number of NK cells in peripheral blood in humans and in the spleen in animals using flow cytometry. Recently, the intracellular levels of perforin, granzymes, and granulysin determined by flow cytometry have also been used in the evaluation of NK cell function. This chapter will describe the methods for NK cell assays in immunotoxicity testing.
Insights
Natural killer (NK) cell function is crucial for immune defense. This chapter details methods for evaluating NK cell activity in immunotoxicity testing, including cytolytic assays and flow cytometry.
Area of Science:
- Immunology
- Toxicology
Background:
- Natural killer (NK) cells are vital immune cells involved in defense against viral infections and tumor surveillance.
- NK cell-mediated cytotoxicity involves the release of granules containing cytotoxic molecules like perforin, granzymes, and granulysin.
- Evaluating NK cell function is critical in immunotoxicity testing to assess potential adverse effects of substances on the immune system.
Purpose of the Study:
- To describe established and emerging methods for assessing natural killer (NK) cell function within the context of immunotoxicity testing.
- To provide a comprehensive overview of techniques used to evaluate NK cell-mediated immune responses.
Main Methods:
- Cytolytic activity assessment using the chromium-51 ((51)Cr)-release assay against target tumor cells.
- Quantification of NK cell populations in peripheral blood (humans) and spleen (animals) via flow cytometry.
- Determination of intracellular perforin, granzyme, and granulysin levels by flow cytometry as indicators of NK cell function.
Main Results:
- The (51)Cr-release assay measures the direct cytotoxic capacity of NK cells.
- Flow cytometry allows for enumeration of NK cells and analysis of their functional mediators.
- Intracellular cytokine staining and granule protein detection provide insights into NK cell activation and effector function.
Conclusions:
- A combination of functional assays, including cytolytic activity and intracellular marker analysis, provides a robust evaluation of NK cell function in immunotoxicity studies.
- Flow cytometry offers versatile approaches for both quantifying NK cell numbers and assessing their functional status.
- These methods are essential for understanding the impact of xenobiotics on immune competence and for regulatory safety assessments.
