Relative response of RTEs and resident cells is dependent on the conditions of activation. (A-C) Sorted CD4⁺ LN RTEs and resident cells from RAG2p-GFP^+/− neonates (A) and adults (B) were activated with PBαCD3 and APC for 48 hours. Supernatants were then harvested for cytokine-specific ELISA. (C) The data from panels A and B were regraphed to show a comparison of neonatal and adult RTEs activated with PBαCD3 and APC. Graphs represent pooled data from 4 independent experiments and are shown as the mean ± SEM; n = 34 to 44 neonates and 6 adults per experiment. (D-F) Sorted CD4⁺ LN RTEs and resident cells from neonatal (D) and adult (E) RAG2p-GFP^+/− were activated with PBαCD3 and αCD28 in the presence or absence of 10 ng/mL IL-7 for 48 hours. Supernatants were then harvested for cytokine-specific ELISA. Graphs represent pooled data from 4 independent experiments and are shown as the mean ± SEM. (F) The data from panels D and E were regraphed to show a comparison of neonatal and adult RTEs activated in the presence of IL-7; n = 25 to 35 neonates; n = 4 to 6 adults per experiment.