Natural Killer (NK) Cell Assays in Immunotoxicity Testing

Area of Science:

• Immunology
• Toxicology

Background:

• Natural killer (NK) cells are vital for innate immunity, defending against viral infections and tumors.
• NK cell-mediated cytotoxicity involves the release of granules containing perforin, granzymes, and granulysin.
• Evaluating NK cell function is critical in immunotoxicity testing to understand chemical impacts on the immune system.

Purpose of the Study:

• This chapter details methods for assessing natural killer (NK) cell function in immunotoxicity testing.
• It highlights the importance of evaluating NK cell activity for safety assessments.
• The goal is to provide a comprehensive overview of relevant NK cell assays.

Main Methods:

• Cytolytic activity is measured using the chromium-51 (⁵¹Cr)-release assay against target tumor cells.
• Flow cytometry quantifies NK cell numbers in peripheral blood (humans) and spleen (animals).
• Intracellular levels of perforin, granzymes, and granulysin are determined via flow cytometry.
• Chemical-induced apoptosis in NK cells is also employed as an assessment method.

Main Results:

• Various methods exist to evaluate NK cell function, including cytotoxicity assays and cell enumeration.
• Intracellular granule content analysis provides insights into NK cell effector mechanisms.
• Apoptosis assays reveal direct chemical toxicity to NK cells.
• These assays collectively contribute to a comprehensive immunotoxicity evaluation.

Conclusions:

• NK cell assays are essential tools for immunotoxicity testing.
• A combination of functional and phenotypic assessments provides a robust evaluation of NK cell health and activity.
• Understanding NK cell responses is key to identifying potential immune-disrupting chemicals.