CD4 and type 1 diabetes mellitus: In contrast, other studies have shown that in NOD CD28-/- mice, adoptive transfer of islet antigen-specific pTregs was equally effective as tTregs in controlling T1D [33], and in one study, co-transfer of TCR transgenic BDC2.5tg+ pTregs with BDC2.5tg+ CD4+ T cells was sufficient to control T1D in NOD RAG1-/- mice [48].