The immune system is tasked with detecting and responding to infections anywhere in the body. To accomplish this task requires the coordinated migration of immune cells and highly dynamic interactions of the migrating cells with their environment. Lymph nodes play a central role in this process by acting as local filter stations that prevent the spread of invading microbes and by providing a sophisticated environment to initiate and regulate innate and adaptive immune responses to antigens derived from pathogens, malignant cells and vaccines. To this end, lymph nodes harbor specialized antigen presenting cells and constantly recruit diverse lymphocyte subsets that engage in continuous immune surveillance and mount protective effector and memory responses.

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Our laboratory has developed intravital microscopy techniques that allow us to identify and track the intra- and extravascular trafficking and dynamic interactions of different immune cell subsets within lymph nodes of anesthetized mice. Using fluorescence imaging strategies, we have traced the dissemination of invading bacteria and viruses via the lymph and analyzed how lymph-borne pathogens are handled upon entering a lymph node. We have characterized how pathogen-derived antigens are presented to T and B lymphocytes and how the in vivo kinetics of antigen recognition impact anti-microbial immunity and the formation and quality of immunological memory.

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This lecture will provide an overview of our lymph node imaging strategies and summarize key insights that have been gained from their use to dissect the mechanisms and consequences of the multi-facetted immune responses to infections.

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