To confirm that this enhanced antigen rejection by B6 mtDNANZB Treg cell function applied to a mouse tumor challenge, we injected 0.1 × 106 B16F10 tumor cells into Rag−/− mice 1 mo after their adoptive transfer with 1 × 106 Tconv CD4+ cells from mtDNAB6 mice and 0.5 × 106 Treg cells from either mtDNAB6 or mtDNANZB mice. This evidence concerns the gene CD4 and neoplasm.