Background: Loading of dendritic cells (DCs) with tumor cell (TC) preparations is an attractive method for vaccine preparation because the entire antigen repertoire of a tumor is processed and presented by the DCs, thus allowing the simultaneous stimulation of T-helper cells and cytotoxic T-lymphocytes. However, optimal loading conditions have still to be defined.
Materials and methods: DCs were pulsed either with tumor lysates, apoptotic or necrotic preparations of a breast cancer cell line and subsequently used to stimulate autologous T-lymphocytes. Antigen loading was quantified using immunofluorescent-based methods.
Results: Four hours co-incubation of apoptotic TCs or tumor lysates with DCs undergoing maturation resulted in effective DC-loading. However, the DCs pulsed with apoptotic TCs were best in stimulating interferon-gamma (INF-gamma) secretion as the effector function of autologous T-cells.
Conclusion: Tumor lysates are in common use for DC-based vaccine manufacturing. However, our data indicate an advantage of apoptotic TC-preparations in regard to antigen loading effectiveness as well as the loaded DC's capacity to activate T-cells.