By Jennifer Ellis and Gunjan Choudhary
Immuno-oncology, or cancer immunotherapy, investigates how the immune system reacts to cancer, how cancer cells respond, and how the immune system can be manipulated to enhance anti-tumor action. Flow cytometry introduces a powerful and versatile technology into these studies, enabling in-depth analysis of cell signaling and behavior.
Our immune systems are built to protect us from harmful foreign substances, like bacteria and viruses, and abnormal cells, like cancer cells. In the latter case, the job of our immune system is to target and destroy such cells. Sometimes, however, cancer cells find a way to evade the immune response, allowing the cells to grow and spread. This is where immuno-oncology comes in. Research in this growing field focuses on finding treatments that work with our immune systems so that they can function as they should to fight cancer. To learn about the different types of immuno-oncology, read Immunotherapy: The Next Frontier for Cancer and to get a better understanding of current therapies, read Advances in Immunotherapy in Cancer.
Since immuno-oncology research focuses heavily on cells, the various types and their behavior in cancer, the use of flow cytometry to interrogate these cells is a no brainer. Flow cytometry allows you to identify cellular markers through surface or intracellular staining techniques. These markers can, in turn, be used to identify different cell types, which can come in handy when developing cell-specific therapies. For example, CD4 is a standard marker for T cell subsets that can also be found on natural killer cells, innate lymphoid cells, and macrophages. It is involved in T cell activation and subsequently provides a foundation for T cell therapies against cancer (Wang et al. 2014).
In addition, flow cytometry easily integrates into immuno-oncology due to its ability to characterize, count, and sort fluorescent-labeled cells based on fluorescence emission. The ability to quantify and characterize specific subsets of cell populations, such as circulating T cells, provides an opportunity to better gauge the immunogenicity of a therapy and enhance our understanding of a complex immune response.
So, what are the steps in immuno-oncology research and how does flow cytometry fit into all of it?