FIGURE 1.

Immunological characteristics of tumor patients receiving anti-CTLA-4 antibodies associated with improved clinical outcome or therapy resistance. A high baseline expression of T_reg cell-associated FoxP3 and IDO, and a treatment-induced increase of tumor-infiltrating T lymphocytes are associated with better clinical efficacy of CTLA-4 blockade. Anti-CTLA-4 therapy enhances the frequency of intratumoral ICOS⁺CD4⁺ T cells that is correlated with better OS. A proportion of these ICOS⁺CD4⁺ T cells is characterized by the production of IFN-γ. Non-responders to anti-CTLA-4 therapy show a higher percentage of PD-L1- or VISTA-expressing CD4⁺ T cells, CD8⁺ T lymphocytes, and CD68⁺ macrophages in posttreatment tumor samples.