title: Lymph node - an organ for T-cell activation and pathogen defense.
abstract: The immune system is a multicentered organ that is characterized by intimate interactions between its cellular components to efficiently ward off invading pathogens. A key constituent of this organ system is the distinct migratory activity of its cellular elements. The lymph node represents a pivotal meeting point of immune cells where adaptive immunity is induced and regulated. Additionally, besides barrier tissues, the lymph node is a critical organ where invading pathogens need to be eliminated in order to prevent systemic distribution of virulent microbes. Here, we explain how the lymph node is structurally and functionally organized to fulfill these two critical functions - pathogen defense and orchestration of adaptive immunity. We will discuss spatio-temporal aspects of cellular immune responses focusing on CD8 T cells and review how and where these cells are activated in the context of viral infections, as well as how viral antigen expression kinetics and different antigen presentation pathways are involved. Finally, we will describe how such responses are regulated and 'helped', and discuss how this relates to intranodal positioning and cellular migration of the various cellular components that are involved in these processes.
authors.affiliation: Institute of Medical Microbiology and Hygiene & FZI Research Center for Immunotherapy, University of Mainz Medical Center, Mainz, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Gasteiger
authors.affiliation: Institute of Experimental Immunology, University of Bonn, Bonn, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Ataide
authors.affiliation: Institute of Experimental Immunology, University of Bonn, Bonn, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kastenmüller
mesh_terms: D056704:Adaptive Immunity; D000818:Animals; D017951:Antigen Presentation; D000956:Antigens, Viral / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002465:Cell Movement; D003713:Dendritic Cells / Q000276:immunology*; D054884:Host-Pathogen Interactions; D006801:Humans; D008198:Lymph Nodes / Q000033:anatomy & histology / Q000276:immunology*; D008213:Lymphocyte Activation; D014777:Virus Diseases / Q000276:immunology*
chemical_list: D000956:Antigens, Viral
keywords: T cells; dendritic cells; infectious diseases; in vivo imaging; lymph nodes; macrophages