Figure 1.

Potential scenarios of DC crosstalk in anti-tumor immunity. (A) Describes a scenario where an effective anti-tumor immune response would rely solely on cDC1 functions. cDC1s can activate both CD8 T cells and CD4 T cells through MHC class I- and MHC class II-mediated antigen presentation, respectively. Activated CD4 T cells provide licensing signal to cDC1s, which relay that help to CD8 T cells. Helped CD8 T cells have enhanced cytotoxic properties to efficiently kill tumor cells. (B) Describes multi-cellular interactions to achieve full-strength CTL responses against tumor. In this scenario, cDC1s predominantly activate CD8 T cells and cDC2s predominantly activate CD4 T cells. Activated CD4 T cells, in addition to providing help to maximize CTL responses can directly exhibit anti-tumor responses. Activated pDCs can modulate the TME mainly via type I IFN production, but can also activate CD4 T cells via MHC class II-mediated antigen presentation. Solid line indicates strong experimental evidence in tumor setting and dashed line indicates data in non-tumor setting. Thick line indicates predominant function.