Precocious Interleukin 21 expression in naïve mice defines a novel stage of T-follicular helper cell development. Mus musculus

To define early forming IL21-expressing CD4+ T cells at the transcriptional level, we performed RNAseq on FACS-purified splenic CD4+ T cells from naïve 4 wk old IL21-VFP reporter mice based on the following criteria: naïve ICOSlo/- VFP- (N); activated ICOShi VFP- cells not expressing IL21 (ACT); and activated IL21-expressing cells ICOShi VFP+ cells (ACT IL21) Overall design: mRNA profiles of FACS-purified VFP-ICOS-, VFP-ICOS+, and VFP+ICOS+ CD4+ cell pools from naïve 4 wk old IL21-VFP reporter mice were generated by deep sequencing, in duplicate, using Illumina MiSeq