Intracellular cytokine staining is a popular method for visualizing cellular responses, most often T-cell responses to antigenic or mitogenic stimulation. It can be coupled with staining for other functional markers, such as upregulation of CD107 or CD154, as well as phenotypic markers that define specific cellular subsets, e.g., effector and memory T-cell compartments, NK cells, or monocytes. Recent advances in multicolor flow cytometry instrumentation and software have allowed the routine combination of 12 or more markers, creating some technical and analytical challenges along the way, and exposing a need for standardization in the field. Here, we will review best practices for antibody panel design and procedural variables for multicolor intracellular cytokine staining, and present an optimized protocol with variations designed for use with specific markers and sample types.
Keywords: AIDS vaccine research; Antigen-specific; Fixation; Intracellular staining; Multicolor; Permeabilization; Polychromatic; T cells.