T Cell and Dendritic Cell Interactions in Lymphoid Organs: More Than Just Being in the Right Place at the Right Time

The initiation of T lymphocyte responses within secondary lymphoid organs involves interactions with different subsets of dendritic cells (DCs). Recent studies have revealed the complexity of microanatomical organization within lymphoid organs. Exactly how T cells and DCs locate each other and the type of cellular interactions required for optimal priming of effector and memory T cell responses are beginning to be unraveled. Here we review advances in our understanding of how T cell priming is choreographed during infections, highlight the importance of cell positioning in this process and discuss how a spectrum of cellular interactions shapes T cell activation and differentiation.