Figure 2.

A model for anti-tumor immunity in the setting of checkpoint blockade. (A) In solid tumors, anti-tumor immunity is mediated primarily by CD8+ T cell responses that are amplified in the setting of PD-1 blockade. However, in CHL this is mitigated by downregulation of MHC-I in the majority of cases. (B) This may predispose RS cells to killing by NK cells, which also express PD-1. Similarly, RS cell downregulation of MHC-II may limit CD4+ T cell responses following checkpoint blockade, but CD4+ T cells can also be primed by other APCs within the CHL microenvironment that do express MHC-II. Additionally, checkpoint blockade may impair the immunosuppressive function of infiltrating regulatory T cells, increasing productive T cell activation.