RAG1 and neoplasm: Transfer of CD8+ OTI and CD25-depleted CD4+ OTII T cells into RAG1−/− tumor-bearing mice 3 days before analysis provided a model in which significant conversion of CD4+ T cells into Treg was unlikely to occur, but CD4+ T cells could provide help to DC thereby rescuing potential defects in DC function due to lymphopenic conditions [46].