On the Twentieth Anniversary of Dendritic Cell Vaccines - Riding the Next Wave.

In the mid 1990's, a convergence of discoveries in dendritic cell (DC) biology and tumor antigen identification led investigators to study DCs as adjuvants for cancer vaccines. On the twentieth anniversary of a seminal clinical study by Jacques Banchereau and colleagues, we revisit the key events that prompted the initial wave of DC vaccine clinical studies and lessons learned that, in our opinion, helped forge the path for the field that we now call immuno-oncology. It is essential to recall that prior to the discovery of immune checkpoint therapy and chimeric antigen receptor (CAR) T-cell therapy, skepticism prevailed regarding the potential therapeutic benefit of immunotherapies. In hindsight, we can now appreciate how the early DC cancer vaccine trials helped investigators sustain their attention on adaptive immunity specific for malignant cells. These vaccines demonstrated clear evidence for induction of antigen-specific T cells and were well tolerated despite low rates of objective clinical response. In the context of the current era some 20 years later, harnessing DC vaccines has been shown to increase the breadth and diversity of tumor-specific T cells, and by trafficking to sites of metastases promote an inflamed tumor microenvironment. See related article by Banchereau and colleagues, Cancer Res 2001; 61:6451-8.