Uptake of Autologous and Allogenic Tumor Cell Antigens by Dendritic Cells

Background: Dendritic cells (DCs) are professional antigen presenting cells (APCs), and there is considerable interest in their application as a cellular adjuvant for cancer immunotherapy. Previous studies indirectly demonstrated that DCs were able to take up tumor lysate (crude soluble tumor antigens) and also cross-present tumor associated antigens (TAA) which elicits anti-tumor immune response. Objective: To provide direct evidence that demonstrates the uptake of tumor lysate by DCs and to find out whether this capability is restricted to allogenic or autologous tumor lysate preparation. Methods: DCs were generated from magnetic bead-isolated monocytes of B-CLL patients as well as healthy donors. Proteins of tumor lysate were conjugated with FITC. Their uptake by autologous as well as allogenic DCs was analyzed using FACS flowcytometry system. Results: In both autologous and allogenic experiments, green fluorescence intensity (FL1) of immature DCs incubated with FITClabeled tumor lysate was clearly higher than unpulsed counterparts, which were considered as background. Conclusion: Immature DCs are able to efficiently take up FITClabeled tumor lysate of autologous as well as allogenic sources. This finding confirms the results of previous studies, which have demonstrated that tumor lysate-pulsed DCs were able to elicit cytotoxic anti-tumor response and concluded that DCs could take up tumor lysate.