CD28 and food allergy: In the present study, induction of Tregs using the Abs-combination produced highly stable and highly suppressive Tregs, even from splenic CD4+ T cells from untreated Rag23–3 mice, suggesting that activating naive T cells from untreated mice via both CD3 and CD28 mAbs can produce Tregs (iTregs) having persistent suppressive abilities in food allergy.