Complementing T-cell function: An inhibitory role of the complement system in T-cell-mediated antitumor immunity

New data from Wang and colleagues show that complement C3 suppresses the function of CD8⁺ tumor-infiltrating T cells by inhibiting IL10 production, and targeting the complement receptors C3aR and C5aR enhances the antitumor activity of immune checkpoint blockade. Their results not only define a new role of complement receptors as T-cell coinhibitory receptors, but also are useful in the development of novel strategies to improve the effectiveness of cancer immunotherapy.