Longitudinal multi-omic immune profiling of the healthy pediatric immune system and its response to vaccination 3300

Abstract Description Investigations of human immune responses typically focus on adults, resulting in limited knowledge of the pediatric immune system and how it responds to distinct challenges early in life. To bridge this gap, we conducted a 3-year longitudinal multi-omic profiling study of 46 healthy children aged 11-13 as they received flu, HPV, DTaP, and COVID vaccines. This dataset includes scRNAseq of > 3.5 million PBMCs classified into 70 immune cell types based on our Immune Health Atlas, as well as plasma proteomics and high-dimensional flow cytometry. We are utilizing this dataset to characterize the pediatric immune system at baseline and in response to acute and chronic challenges as it compares to the adult immune system, with the ability to compare neoantigen and recall responses within the same children. This analysis revealed age-independent and age-dependent response patterns, with similar cellular compositions and gene-expression changes characterizing response to chronic CMV infection between children and adults but heightened activity in specific cell types responding to flu vaccination in children. We also identified increased activity in specific cell types in response to vaccines that elicit recall as opposed to neoantigen responses, providing a means to understand how immune memory is established and re-engaged in children. These initial findings lay the groundwork upon which we can build and deepen our understanding of immune dynamics in early adolescence. Topic Categories Vaccines and Immunotherapy (VAC)