Cancer Immunotherapy UsingIn vitroGenetically Modified Targeted Dendritic Cells

Abstract

Modest clinical outcomes of dendritic cell (DC) vaccine trials call for novel strategies. In this study, we have created a chimeric CD40 molecule that incorporates a single chain Fv (scFv) molecule specific for human ErbB2 antigen and fusing to the membrane spanning and cytosolic domains of murine CD40. After adenoviral transfer to bone marrow–derived DC, this chimeric receptor (CR) induced nuclear factor-κB (NF-κB)–dependent DC activation and effector function when cultured with immobilized ErbB2 protein or ErbB2-positive tumor cells in vitro. In vivo migration assays showed that ∼40% injected CR-modified DC (scFv-CD40-DC) effectively migrated to ErbB2-positive tumors, where they were activated after ErbB2 antigen stimulation, and sequentially homed into the draining lymph nodes. In murine ErbB2-positive D2F2/E2 breast tumor (BALB/c) and EL4/E2 thymoma (C57BL/6) models, i.v. injection of 1 × 10⁶ scFv-CD40-DC significantly inhibited tumor growth and cured established tumors. Importantly, the cured mice treated by injection of scFv-CD40-DC were effective in preventing both ErbB2-positive and parental ErbB2-negative tumor rechallenge. Analysis of the underlying mechanism revealed that i.v. infusion of scFv-CD40-DC elicited tumor-specific CTL responses, and the transfer of CTLs from scFv-CD40-DC–treated mice protected naive mice against a subsequent tumor challenge. These results support the concept that genetic modification of DC with tumor-associated antigen-specific CD40 chimeric receptor might be a useful strategy for treatment of human cancers. [Cancer Res 2008;68(10):3854–62]