Regulation of Tumor Immunity by Tumor/Dendritic Cell Fusions

Figure 4

Activation or inactivation of T cells by tumor/DC fusions. After acquired antigens in the periphery, tumor/DC fusions migrate to the draining lymph nodes, where they encounter a cognate CD4+ or CD8+ T cells. The mature tumor/DC fusions produce stimulatory factors, such as IL-12 and heat-shock proteins (HSPs), while the immature fusions produce suppressive factors (TGF- 𝛽, IL-10, or IDO, etc.). High expression of costimulatory and MHC class I and II molecules by mature fusions is essential to promote survival and proliferative capacity of the activated CD8+ CTLs. Mature fusions induce efficient CD8+ T-cell activation with high production of perforin and granzyme B. On the other hand, immature fusions may induce, at least in part, Tregs. In tumor microenvironment, the consequence of products from tumor cells enhances local suppressive immunity.