CD4 and allergic disease: To transcriptionally characterize the CD4+ T cell response to OVA in the context of feeding, tolerance, and allergy, we performed scRNAseq on Tomato+ CD62L– (fate-mapped ex-naïve) and Tomato– CD62L– (pre-existing non-naïve) CD4+ T cells (pooled at a ratio of ∼1:2 Tomato+:Tomato– to evenly enrich for Tomato+ cells) from the IE and LP of SPF iSellTomato mice on day 26 of the treatment protocols (see Fig. 6 A).