Visualizing Endogenous Effector T Cell Egress from the Lymph Nodes.

Local anatomy of lymphoid tissues during infection has emerged as a critical regulator of immunity; thus, studying the cellular choreography in the context of an intact tissue environment in situ is crucial. Following an infection, the local pathogen-specific T cell migration and the subsequent egress of effector T cells from the draining lymph nodes are important and complex biological processes. The mechanisms that regulate this complex process can now be investigated by directly visualizing T cell dynamics in vivo using intravital two-photon (2P) microscopy. In addition, static whole-mount imaging technique can provide us with a comprehensive assessment of global changes in the distribution of cellular populations within an intact tissue. Thus, in this chapter, we detail methods to visualize the migration and egress of endogenous antigen-specific CD8 T cells following viral infection using two methods-intravital 2P microscopy and multicolor whole-mount in situ tetramer staining.