RNA-sequencing of bulk CD19+ Thymic B cells from young (5 week) and aged (10-24 month) mice

Thymic B cells have been recently shown the ability to be licensed to express Aire, a critical transcription factor involved in the expression of self-antigens in the thymus which are critical for clonal deletion of autoreactive T cells and maintenance of self-tolerance. Mutations in AIRE cause systemic autoimmunity in humans and autoimmunity with varying degrees of severity in different mouse strains. Thymic B cells have been studied in young animals, but studies of this population with age are lacking. Given the thymus undergoes age-associated atrophy in its stromal compartment, we hypothesized that aged thymic B cells may under go changes with age which may impact their ability to mediate clonal deletion of autoreactive T cells and may contribute to age-associated increases in autoimmune prevalence. By comparing the transcriptome of young and aged thymic B cells we find that Aire and transcriptional activators of Aire are signficantly decreased with age. Thymic B cells were enriched by incubating total thymocytes with CD19-APC (Clone: MB19-1) followed by incubation with anti-APC magnetic beads (Miltenyi Biotec). Enriched cells were then sorted using a BD FACS ARIA to a minimum purity of 98.5%, RNA extracted and analyzed