Inducible bronchus-associated lymphoid tissues (iBALT) serve as sites of B cell selection and maturation following influenza infection in mice

GC-like structures within iBALT serve as a distinct niche that independently support the maturation and selection of B cells primarily targeted against the influenza virus nucleoprotein. Our findings suggest that iBALT, which are positioned at the frontline of the lung mucosa, drive long-lived and unique GC reactions that contribute to the diversity of the humoral response targeting influenza. GC and memory B cells were sorted from various tissues in influenza PR8-infected mice. B cells were identified as Live/Dead negative, F4/80-, Streptavidin-, CD3-, CD45+, B220+ and intravenous CD45.2-. GC (CD38lo/GL7+) or memory (CD38hi/GL7-) B cells were sorted. Transcriptional profiling and differential gene expression was performed using RNA sequencing.