Dendritic Cells at the Center of Reactive Tumor Immunity

Elimination of tumors is typically dependent on T cells, which require prior or ongoing activation signals. These dependencies form the basis for our understanding of "tumor-reactive immunity" and for the successes of immunotherapies, particularly immune checkpoint blockades. Over the years, tremendous work has been done towards understanding the biology of this reactive immunity and early investigation identified dendritic cells (DC) as key contributors. Recent advances have shed more light on dendritic cell heterogeneity in tumors, revealing specialized roles for each subtype. In addition, the network of cellular interactions surrounding DCs has grown as additional cell types have been revealed to variously influence how the immune system can become most effective at eliminating malignancies. Greater understanding of intratumoral DC biology has empowered investigators to engineer dendritic cell vaccines and consider other approaches to augment this component of reactive immunity, towards the generation of anti-tumor immune responses de novo. In this review, we will discuss the state of the field, recent advances and suggest what the near future of scientific inquiry could entail.