Fusion hybrids of dendritic cells and autologous myeloid blasts as a potential cellular vaccine for acute myeloid leukaemia

We assessed the potential of tumour cell/dendritic cell fusion hybrids to generate in vitro anti-leukaemic T-cell responses following co-culture with autologous remission lymphocytes in six patients with acute myeloid leukaemia (AML). Comparison was made to anti-leukaemic responses induced by mature dendritic cells (mDC) co-cultured with autologous, irradiated myeloid blasts. Fusion hybrids induced anti-leukaemic T-cell immune responses in three of six patients. Tumour-pulsed mDC induced T-cellular responses in two other patients. Only one of six patients remission lymphocytes failed to develop leukaemia-directed immune responses following stimulation with either construct. Anti-proliferative properties of fusion hybrids against allogeneic lymphocytes were observed in mixed lymphocyte-leukaemia reactions and were found not to be specific to the cell fusion partners and did not prevent the ability of AML-mDC heterokaryons to induce autologous anti-leukaemic cytotoxicity. We conclude that tumour cell/dendritic cell fusion hybrids hold promise as a cellular vaccine for AML.