Flow Cytometric Analysis of Mouse Brain CD8⁺ T Cell Activation

Cytotoxic CD8⁺ T cell lymphocytes are pivotal for fighting infections with intracellular pathogens, e.g., viruses. Moreover, recent studies have elucidated the role of CD8⁺ T cells in various neuroinflammatory diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), and stroke. Therefore, the characterization of brain CD8⁺ T cells at the single-cell level is pivotal for understanding their state and function, e.g., in preclinical mouse models. Here, flow cytometry emerges as a versatile tool offering distinct techniques tailored to different facets of T cell activation. In this chapter, we provide protocols utilizing multicolor flow cytometry and cytokine secretion assays to analyze brain CD8⁺ T cell activation via the detection of surface lineage markers, extracellular and intracellular activation markers such as CD39, CD279, and granzyme B, or via measuring cytokine expression levels.