FluPRINT cohort: Mass Cytometry (CyTOF) profiling of T stem cell-like memory (TSCM) responses to LAIV in children

The development of universal influenza vaccines relies on eliciting broad CD8+ T-cell immunity, specifically the T stem cell-like memory (TSCM) subset. This study investigates the immunological determinants governing the expansion of influenza virus-reactive TSCM cells in a pediatric cohort (n = 19, ages 4-6y) immunized with the live attenuated influenza vaccine (LAIV). Experimental Design The dataset includes paired .fcs files for each subject (Baseline/Visit 1 and Post-vaccination/Visit 2) under two conditions: Unstimulated Controls: Matched samples processed in parallel without peptide stimulation. Antigen Stimulation: Thawed PBMCs stimulated for 12-16 hours with a comprehensive peptide pool library spanning the entire proteome of influenza A/California/07/2009, consisting of 483 20-mers and 24 9-mers (full peptide library published in Tomic et al, 2019, JI, DOI: 10.4049/jimmunol.1900033) Methodology Panel: Cells were stained with a 36-marker metal-labeled antibody panel designed to distinguish T-cell memory subsets and intracellular cytokine production. The workflow included surface labeling, fixation (Maxpar Fix I), permeabilization (Maxpar Perm Buffer), and intracellular staining. Acquisition: Data were acquired on a Fluidigm Helios mass cytometer. Analysis Software: Data were originally analyzed using Cytosplore and FlowJo.