Project Summary/Abstract This CCHI U19 Program aims to determine how perturbations of the human immune system leads to do durable changes that impact future immune responses. Core C of this Immune Perturbation Study Group Program application will be central to the scientific efforts of this consortium. A unique and comprehensive pipeline has been created alongside an expansive repository of existing samples and background data to measure and analyze high dimensional immune landscapes using quantification of all circulating immune cell types with activation status, serology and systemic inflammation over the course of different perturbations outlined in the Projects. This pipeline will be maintained and expanded to include additional longitudinal samples from subjects with post-acute sequalae of COVID-19 (Project 1), subjects cured of HCV (Project 2), and subjects receiving vaccines during anti-PD-1 therapy (Project 3). This concerted effort will maintain high throughput of immune phenotyping to catalyze scientific efforts across the consortium, including analyzing samples accrued by Core B. Thus, Core C provides a central and integrative service that will allow studies in the different Projects to inter- relate around immune landscapes during immune perturbation.