Measuring natural killer cell cytotoxicity by flow cytometry.

Area of Science:

• Immunology
• Cellular Biology
• Diagnostic Assays

Background:

• Natural killer (NK) cell cytotoxic function is vital for immune defense against viral infections and cancer.
• The traditional ⁵¹Chromium (⁵¹Cr)-release assay, while standard, suffers from radioactive reagent use and inconsistent standardization.
• There is a need for a reliable, non-radioactive method for assessing NK cell activity in clinical settings.

Purpose of the Study:

• To establish and validate a flow cytometry (FC)-based assay for measuring NK cell cytotoxicity.
• To define reference values for NK cell activity in the Hong Kong population.
• To compare the performance of the FC method against the established ⁵¹Cr-release assay.

Main Methods:

• Development of a flow cytometry protocol for NK cell cytotoxicity measurement.
• Assessment of the FC protocol using normal peripheral blood samples.
• Validation by comparing FC results with the ⁵¹Cr-release assay in healthy individuals and patients with suspected NK cell dysfunction.

Main Results:

• Reference values for NK cell activity were established for the local Hong Kong population.
• The FC method demonstrated comparable results to the ⁵¹Cr-release assay.
• The FC assay proved suitable for patient testing and clinical settings.

Conclusions:

• Flow cytometry provides a clinically valid and reliable method for measuring NK cell cytotoxicity.
• This non-radioactive assay overcomes limitations of the traditional ⁵¹Cr-release assay.
• The developed FC protocol is suitable for routine patient diagnostics and immunological research.