Cancer immunotherapy with exosomes requires B-cell activation

Abstract

Exosomes derived from dendritic cells (dexosomes) induce potent antitumor immune responses in mice. We have shown that the efficacy of dexosome-elicited antitumor immunity relies on the presence of both T- and B-cell dexosome-associated epitopes. Hence, the inclusion of B-cell epitopes in anticancer vaccines is crucial for the success of this immunotherapeutic intervention.

Keywords: B cells; CD4+ T cells; CD8+ T cells; dexosomes; exosomes; marginal zone B cells; melanoma.

Figure 1. Dexosome-mediated splenic immunostimulation. Upon intravenous administration, circulating dexosomes are taken up in the spleen either by marginal zone B cells (MZBs)—and hence transported to follicular dendritic cells (FDCs) for B-cell activation—or by dendritic cells (DCs), which activate T lymphocytes in the T-cell zone. B cells can further activate helper T cells at the B/T-cell border to boost subsequent cytotoxic T-lymphocyte responses or directly stimulate CD8⁺ T cells following CD4⁺ T-cell priming.