Cytokine Expression by T Follicular Helper Cells

: T follicular helper (Tfh) cells are a specialized subset of CD4+ T cells located within temporary structures known as germinal centers (GC) formed within B cell follicles of secondary lymphoid organs. In the GC, Tfh cells facilitate the production of high-affinity antibodies through secretion of effector cytokines, such as IL-21 and IL-4, and through cell-to-cell interactions. The flow cytometric-based method described here allows the detection of intracellular cytokines within the Tfh population of secondary lymphoid organs (e.g., spleen, lymph nodes, and lymphoid nodules such as Peyer's patches), enabling the study of Tfh responses to different stimuli in the context of immunity and autoimmunity.