Cell-based Flow Cytometry Assay to Measure Cytotoxic Activity

Alessandra Noto; Pearline Ngauv; Lydie Trautmann

doi:10.3791/51105

Cell-based Flow Cytometry Assay to Measure Cytotoxic Activity

JoVE Journal
Immunology and Infection

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JoVE Journal Immunology and Infection

Cell-based Flow Cytometry Assay to Measure Cytotoxic Activity

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10:14 min

December 17, 2013

DOI: 10.3791/51105-v

Alessandra Noto¹, Pearline Ngauv¹, Lydie Trautmann¹

¹Vaccine and Gene Therapy Institute of Florida

Overview

This protocol describes a sensitive, cell-based cytotoxicity assay to measure the cytotoxic activity of antigen-specific CD8+ T cells. By assessing the decrease in live target CD4+ T cells in the presence of effector CD8+ T cells, this assay provides a direct evaluation of cytolytic activity.

Key Study Components

Area of Science

Immunology
Cytotoxicity Assays
Flow Cytometry

Background

CD8+ T cells play a crucial role in the immune response against pathogens.
Measuring their cytotoxic activity is essential for understanding immune function.
This assay utilizes primary target cells, enhancing physiological relevance.
Flow cytometry allows for precise quantification of cell populations.

Purpose of Study

To evaluate the cytotoxic activity of antigen-specific CD8+ T cells.
To determine the lytic units of these T cells against target CD4+ T cells.
To provide a reliable method for assessing T cell functionality.

Methods Used

Expansion of effector CD8+ T cells in the presence of specific peptides.
Pulsing target CD4+ T cells with the peptide of interest.
Co-culturing effector and target T cells at varying ratios.
Quantifying cell populations and cytotoxic activity using flow cytometry.

Main Results

Successful measurement of cytotoxic activity of CD8+ T cells.
Quantification of lytic units based on target cell killing.
Demonstrated the effectiveness of using primary target cells.
Provided insights into the dynamics of T cell-mediated cytotoxicity.

Conclusions

This assay is a valuable tool for studying T cell cytotoxicity.
It offers a more physiologically relevant approach compared to immortalized cell lines.
The method can be applied to various immunological studies.

Frequently Asked Questions

What is the main goal of this assay?

To measure the cytotoxic activity of antigen-specific CD8+ T cells.

Why use primary target cells instead of cell lines?

Primary target cells provide a more accurate representation of in vivo conditions.

How are the effector and target T cells prepared?

Effector CD8+ T cells are expanded with peptides, while target CD4+ T cells are pulsed with the same peptides.

What technique is used to quantify the results?

Flow cytometry is used to quantify the populations of effector and target T cells.

What are lytic units?

Lytic units are a measure of the cytotoxic capacity of CD8+ T cells against target cells.

How long are the T cells co-cultured?

The effector and target T cells are co-cultured for six hours.

This protocol describes a sensitive, cell-based cytotoxicity assay. By enumerating the decrease in frequency of live target CD4+ T cells in the presence of an increasing number of effector CD8+ T cells, this assay allows for the direct assessment of cytolytic activity of antigen-specific CD8+ T cells.

The overall goal of this procedure is to measure the cytotoxic activity of antigen-specific CD eight T cells using a cell-based flow cytometry assay. This is accomplished first by expanding effectors CD eight T cells for six days in the presence of the peptide of interest in the second step target CD four T cells are pulses with the peptide of interest and then mixed with unposted CD four TT cells. Next, the effector CD eight T cells and target CD four T cells are co cultured for six hours at different effector to target ratios.

In the final step, the killing of the peptide loaded target CD four T cells and the number of effector CD eight T cells are quantified by flow cytometry. Ultimately, the intrinsic killing capacity of the antigen-specific CD eight T cells expressed in lytic units can be calculated. The main advantages of this technique of oxy matter like aro release assay, is that that this technique uses autologous primary target cells instead of immortalized cell lines and the actual target cell.

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