Fig. 2

Expanding Treg numbers increased their abundance in OIR and retina. a C57BL/6J mice were administered an IL-2/anti-IL-2 mAb complex at postnatal day (P) 5, P6, and P7. Separate cohorts of OIR mice received purified splenic Tregs by adoptive transfer (AT) at P7 and P12. Mice were studied in phase I OIR and phase II OIR and comparisons made to age-matched OIR control mice or OIR mice administered an anti-IL-2 control mAb. FACS revealed that in phase I OIR at P12 b and phase II OIR at P18 c the numbers of Tregs in blood, pooled lymph nodes, and spleen were increased with both treatments (enlarged FACS plots in Supplementary Fig. 3). Fluorochromes are phycoerythrin PE) and allophycocyanin (APC). *P < 0.05, **P < 0.01, and ***P < 0.001 to OIR controls and OIR + anti-IL-2 mAb controls (one-way ANOVA with Mann–Whitney U test). n = 6 mice/OIR control and OIR + anti-IL-2 group and 7 mice/OIR-treated group at P12 and P18. Representative confocal images of flat mounted retinas from Foxp3^rfp mice labeled with isolectin (green) to show blood vessels. In phase I OIR at P10 d and phase II OIR at P18 e, few Foxp3⁺ cells (red) were present in retinal tissue and (arrowhead) and blood vessels (arrows). Asterisk denotes neovascular tuft. In OIR-treated groups, Foxp3⁺ cells were increased in retinal tissue (arrowheads). Scale bar, 50 μm. f, g Foxp3⁺ cells in tissue of the inner retina (one-way ANOVA with Mann–Whitney U test). **P < 0.01 and ***P < 0.001 to OIR control groups. n = 13 mice/OIR control group and 9 mice/OIR-treated group at P10. n = 12 OIR mice, 9 OIR + anti-IL-2 mice and 7 mice/OIR-treated groups at P18. Values are expressed as mean ± s.e.m