A lymph node slice culture model to spatially profile early vaccine responses in human tissue 3287

Abstract Description The activation and spatial interactions of immune and stromal populations in the lymph node (LN) are critical in the formation of adaptive immunity following vaccination. While the induction of immunological memory with vaccination is well established, early responses to vaccines in memory-forming sites such as the LN are less well-characterized in humans. We have developed methods for culturing live human LN slices, which overcome limitations of suspension culture by preserving physiological cell composition, cell-cell interactions, and tissue architecture. To profile acute vaccine responses, we used both LN suspension and slice culture systems stimulated with Merck Measles-Mumps-Rubella (MMR), Pfizer COVID-19 mRNA bivalent booster, or Fluzone influenza vaccines with CITE-seq and 10x Xenium spatial profiling as readouts. CITE-seq revealed an MMR dose-dependent interferon response signature, whereas the Pfizer mRNA vaccine localizes to macrophages, compromising their viability while inducing a glycolytic state in lymphocyte subsets. Xenium profiling recapitulated and provided spatial context for these phenotypes with robust sampling of stromal and innate compartments typically depleted by tissue dissociation. Overall, comparing vaccines with varying antigen/protection profiles in the human LN yielded early, vaccine-specific signatures which may relate to the generation of durable memory responses. Funding Sources Supported by NIH 2U19AI128949-06; DARPA HR001121S0037; NIH 1T32GM145440-01; LiveOnNY and Farber Lab for organ donor tissue samples. Topic Categories Vaccines and Immunotherapy (VAC)