Studying Dendritic Cell-T Cell Interactions Under In Vivo Conditions.

The interactions between dendritic cells and T cells during the initiation of an adaptive immune response underpins one of the most important checkpoints in ensuring that the correct immune response is induced, in order to direct the development of immune tolerance or to mount an immune response against pathogenic organisms. The advent of two-photon intravital imaging allows us to directly study the interactions between dendritic cells and T cells as they occur under physiological conditions, greatly improving our understanding of the dynamic relationship that occurs during T cell activation and expanding our knowledge of how the adaptive immune system is regulated during both priming and memory responses. Here, we describe a technique for the in vivo analysis of the interactions between either CD4+ or CD8+ T cells and dendritic cells as they occur in the popliteal lymph nodes of live mice. The adoptive transfer of both dendritic cells and T cells is utilized here in order to allow investigators to control the time point of interaction being analyzed, the activation state and amount of antigen presented by the dendritic cell, and the maturation/differentiation state of the interacting T cell.