Anti‐tumor effect by dendritic cells stimulated with IL‐2 in OT‐1 model

Abstract

Background:Recently, IKDCs expressing both natural killer (NK) and dendritic cell (DC) characteristics have been described: these NK‐like DCs “convert” from cells with NK cell lytic activity and NK receptor expression, into cells acquiring MHC class II and the requisite molecules for APC function. In an attempt to stimulate IKDC‐like activity in bone‐marrow‐derived DCs (BMDCs), we stimulated the BMDCs with IL‐2. These “DCs‐IL‐2” cells possessed an impressive anti‐tumor effect in mice when injected s.c, mixed with M05 tumor cells.Methods:1) Vaccination with DCs‐IL‐2+MO5 in OT‐1 model; 2) Rechallenge of tumor‐free mice; 3) Flow and image analysis.Results:1) The DCs‐IL‐2‐treatment demonstrated an impressive anti‐tumor effect in that no tumor growth was seen in four of the five mice that received DCs‐IL‐2 + MO5 tumor cells on the right flank and M05 cells alone on the left flank; 2) Three out of the four tumor‐free mice did not grow tumors when re‐challenged with MO5 tumor cells. One mouse developed tumors, but much delayed compared to control mice; 3) Flow data demonstrated that 10–20% of the DCs‐IL‐2 acquired A‐NK phenotypic markers, while maintaining their DC phenotypes.Conclusion:The DCs‐IL‐2 have a promising potential to improve cancer immunotherapy and we will continue to study the phenotype, lineage commitment, and in vivo relevance of these cells.