Intracellular Cytokine Staining (ICS) is an assay used across the biomedical research landscape from basic research to preclinical studies and clinical trials. ICS can allow you to simultaneously measure the expression of surface markers on a cell, like CD4 or CD8 as well as the expression of cytokines produced inside the cell like IL-2 or IL-17. This helps scientists understand not only that the cytokine is present in their sample but also to identify which cell phenotype is producing that specific cytokine.
Take a look at these questions to see how ICS can take your research project to the next level.
1. Do I Need To Measure Multiple Immune Cell Populations In Parallel?
If the answer is yes, ICS is a great assay for this type of study because the unique phenotypes of different cells can be measured using a panel of fluorescently labeled antibodies specific to different cell surface markers and different intracellular cytokines. ICS is extremely customizable, and new flow cytometers can measure upwards of 18 colors, so you can measure multiple immune cell populations in a single experiment.
2. Do I Need To Measure How Cells Respond To A Specific Antigen?
If this is the case, ICS is an excellent option because the initial steps of the assay include stimulating cells in vitro. Most ICS assays include stimulation with a mitogen, which stimulates cells non-specifically and assesses overall function of the cells and serves as a positive control.
3. Can ICS Be Used To Assess Immune Cell Function In Fresh Or Frozen Samples?
It depends. ICS can be completed on fresh or frozen samples, like peripheral blood mononuclear cells, but not all cell populations will survive cryopreservation and your secreted cytokine levels may be affected by the cryopreservation itself. Try a pilot experiment to determine if you can measure your cell populations of interest in fresh or cryopreserved (frozen) samples.
4. Can ICS Be Used In Clinical Trials?
Yes! ICS assays can be validated and used for clinical trials, and this particular assay has been essential to development of numerous vaccines in the 21st century.
Your answers to these questions should help you decide if ICS is a good fit for your research needs. ICS is a technical and time-intensive assay, so seek out expert help as you get started. An experienced flow cytometry user or a contract research organization can help you get the most out of your research.