Detection of T Cell Cytokine Production as a Tool for Monitoring Immunotherapy

There are many complex relationships between tumour cells and effector cells in the immune system. These interactions are controlled predominantly by cytokines, either within the tumour environment, or systemically where the effector cells may be stimulated as a response to the presence of the tumour. Favourable clinical responses in cancer patients have been shown to be associated with enhanced cell-mediated immunity as well as T cell infiltration in tumours. This status is controlled in part by a predominantly Th1 cytokine profile e.g. IFNγ, TNFα and IL-12. Conversely, patients with advancing cancer may have impaired cellmediated immunity as a result of an imbalance of Th1 and Th2 cytokines e.g. IL-4 and IL-10 [6,9,15]. Whilst cytokines have long been known to orchestrate the immune system by allowing communication between regulatory and effector cells, the pleiotropic nature of these molecules results in a very complex environment in which to study any single molecule’s properties. Several in vitro protocols have been developed, which aim to closely reflect cytokine production and T cell function in vivo. However, these assays have been developed in artificial settings and as such only allow conclusions to be drawn within a defined context [11]. The aim of this report is to outline the basic protocols and applications for the detection of intracellular cytokines by flow cytometry, in the context of disease monitoring.