Regulatory T cell suppression assay

To achieve a balance between autoimmunity and immune escape, regulation of immune responses is paramount. One of the important players in regulating adaptive immune responses are regulatory T cells (T_REG). Determining whether your compound of interest impacts T_REG function is important to determine possible (off-target) effects and subsequent (unwanted) altered immune suppression.

This assay will give insight into the capacity of T_REG cells to suppress activation of conventional T(T_CONV) cells. T_REG cells are part of the CD4⁺ T cell population and play a very important role in autoimmunity (suboptimal suppression of T_CONV cells) and oncology (excessive suppression of T_CONV cells). This assay could, for example, be of interest to you if you want to test (immunomodulatory) drugs that influence T_REG-mediated suppression of conventional T cells.

In order to induce suppression, T_REG cells and T_CONV cells are co-cultured in different ratios and a stimulus is added to activate both T cell populations. Proliferation of the T_CONV population is then analyzed as a read-out to assess the extent to which the T_REG cells are able to suppress activation of the T_CONV cells. The assay is customizable in many ways. Total PBMCs can be used as a source of T_CONV cells to closely mimic the in vivo situation. Alternatively, specific T_CONV subsets (e.g. CD8⁺ T_CONV) can be isolated and co-cultured with the T_REG cells. Cells can be stimulated polyclonally, using T cell receptor and CD28 co-receptor crosslinking antibodies, or cells can be stimulated in an antigen-specific fashion. Furthermore, proliferation can be monitored over a longer period of time using a proliferation dye, or during a fixed time window, using radioactive thymidine incorporation. The assay is also easily combinable with cytokine and/or transcription factor analysis via flow cytometry.

Of note, to obtain sufficient T_REG cells to perform suppression assays or other functional assays with T_REG cells, ex vivo expansion may be needed. We can provide the isolation of T_REG cells and subsequent expansion without losing functionality.

Example of how our suppression assay can contribute to your T_REG-related project

T_REG suppression of CD4⁺ and CD8⁺ T_CONV cells 

Total PBMCs were co-cultured with different ratios of T_REG cells and stimulated polyclonally using anti-CD3 and anti-CD28 antibodies. Proliferation was monitored using a violet proliferation dye, and staining for CD4 and CD8 allowed for individual assessment of the suppressive effects on the CD4⁺ and the CD8⁺ T_CONV populations. % suppression for both populations is depicted relative to the level of proliferation without addition of T_REG cells. As shown, the suppressive effect diminishes when less T_REG cells are added to the culture.