CD Markers

As a contract flow lab, FCSL frequently runs immunophenotyping assays for clients, though it is just one of the flow cytometry services we offer. CD Markers are commonly used in immunophenotyping to identify cells based on what molecules are present on the surface of each cell. One of the ways that CD Markers differentiate cells is through immune functions. CD Markers are rarely used individually, more commonly combined into antibody panels for lymphocyte subset identification. This allows very specific cells within the immune system to be separated and analyzed, as there are over 400 different CD Markers.

CD25 is one of the markers frequently analyzed at FCSL. The full name for CD25 is interleukin-2 receptor alpha chain (IL-2RA), in humans. CD25 antibodies are added to samples to determine if the cells present in the samples express CD25 receptors on their surface. CD25 is a signaling molecule for the immune system, regulating white blood cells with roles in tolerance and immunity. One of the main ways CD25 regulates is differentiating immature T cells into effector and memory, or regulatory T cells and as a result is integral in the development of T-cells.

Recently CD25, has become a topic of interest in many research studies, including cancer, autoimmunity, and microbial studies. One of the most interesting finding is a significant increase in CD25(+) regulatory T cells found in patients suffering from gastric and esophageal cancers. CD25 also increases in conjunction to the tumor stage in patients. With these new findings scientists can work on developing immunomodulatory therapies. Research into these types of therapies may provide safer and more effective means of treating these conditions.

FCSL is a contract flow lab that provides high throughput and high capacity flow cytometry services, running multiple flow cytometers with up to 10 color antibody panels daily.  We are proficient in processing a multitude of specimen types including whole blood, frozen PBMCs along with cell culture and tissue processing capabilities. Our flexibility in handling so many specimen types allow for the support of a wide range of flow cytometry assays including: immunophenotyping/lymphocyte subset analysis, receptor occupancy, functional assays and cell viability/apoptosis measurements. Our expert staff is always available to help guide you through these tests and we welcome clients to visit our facility. We encourage sponsor engagement throughout the process. Contact us for more information!


“CD25.” Egyptian Journal of Medical Human Genetics, Elsevier, 2018,

“Cluster of Differentiation.” Wikipedia, Wikimedia Foundation, 3 July 2018,

“IL2RA.” Wikipedia, Wikimedia Foundation, 15 December 2017,

“Interleukin 2.” Wikipedia, Wikimedia Foundation, 26 Apr. 2018,

Kono, Koji, et al. “CD4(+)CD25high Regulatory T Cells Increase with Tumor Stage in Patients with Gastric and Esophageal Cancers.” Cancer Immunology, Immunotherapy, vol. 55, no. 9, 2005, pp. 1064–1071., doi:10.1007/s00262-005-0092-8.

Murphy, Kenneth, et al. Janeway’s Immunobiology. Garland Science, 2017.

Wolf, Anna Maria, et al. “Increase of Regulatory T Cells in the Peripheral Blood of Cancer Patients.” Clinical Cancer Research, vol. 9, no. 2, Feb. 2003, pp. 606–612.