Decoding the immune cells in the fetal brain at murine mid-gestation 4687

Abstract Description Adverse events during gestation can influence long-term offspring immunity by disrupting key fetal developmental milestones. Inflammation can alter the emergence of several fetal immune subsets, however, these studies primarily focus on maternal factors that govern development leaving fetal contributions unknown. Fetal immunity is best characterized in context of the liver, the site of fetal hematopoiesis at mid-gestation. We used a high-dimensional sequencing technology, Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq), that allowed us to simultaneously study surface protein markers and gene expression at a single-cell resolution. Interestingly, we identified two multipotent progenitor cell subsets present in the fetal brain at mid-gestation. The presence of progenitor immune cells in the fetal brain highlights its susceptibility to inflammatory events that occur during development. Therefore, we sought to further characterize the phenotype of immune cells in fetal brain with respect to the fetal liver isolated from murine implantation sites at mid-gestation. We identified eleven clusters of immune cells shared by both the fetal brain and liver, ten of which are of innate immune cells at various stages of development, including both multipotent progenitor populations. Our findings provide foundation to understand fetal immune development and will lead to future work studying the consequences of gestational inflammation on the fetal immune system. Funding Sources Howard Hughes Medical Institute through the Gilliam Fellows Program Topic Categories Neuroimmunology (NEUR)