Dendritic cell (DC)–based cancer vaccines can be prepared with relative ease and have been shown to induce therapeutic antitumor immune responses both in experimental models and, more recently, in the clinic for treatment of hormone-resistant prostate cancer and other malignant neoplasms.1 However, DC vaccination protocols are clearly not yet optimized2 and the generation of more effective regimens continues to be an area of active research. One of the key hurdles in developing an effective DC vaccine is poor access of tumor-specific antigen (TSA) to the intracellular human leukocyte antigen class I pathway, which is required to generate tumor-reactive cytotoxic T lymphocytes (CTLs).3