Anti-Tumour and Immune Enhancing Activities of MLAA-22 379–387 on Acute Myeloid Leukemia

We have earlier demonstrated that MLAA-22_379–387is a novel, acute, monocytic, leukemia-associated antigen epitope in vitro. In this study, the effect and mechanism of MLAA-22_379–387on animals have been further examined. We found that tumour weight and volume had significantly decreased in SCID-injected THP-1 mice with MLAA-22_379–387treatment for two weeks. MLAA-22_379–387induced cytotoxic T lymphocytes (CTL) activity in A549, MCF-7, THP-1, U937 and T2 cells, especially significant CTL activity at effector/target ratio of 50 : 1 in THP-1 cells. The percentage of CD3 + CD8 + T cells had significantly increased, while the percentage of CD4 + CD25 + T cells had significantly decreased in MLAA-22_379–387treatment group compared to other groups. Levels of IL-2, IFN-γand IgG had significantly increased, but levels of TGF-βand IL-10 had significantly decreased after MLAA-22_379–387vac-cination for two weeks. Thus, we may conclude that MLAA-22_379–387treatment effectively improves the immune system, thus indicating tumouricidal capacity in leukaemic mice. These findings highlight the potential application of MLAA-22_379–387 as an efficient target for immunotherapy in acute myeloid leukemia.