Targeted deletion of PD-1 in myeloid cells induces antitumor immunity
Laura Strauss, Mohamed A. A. Mahmoud, Jessica D. Weaver, Natalia M. Tijaro-Ovalle, Anthos Christofides, Qi Wang, Rinku Pal, Min Yuan, John M. Asara, Nikolaos Patsoukis, Vassiliki A. Boussiotis
Abstract
mice, accumulation of GMP and MDSC was prevented, whereas systemic output of effector myeloid cells was increased. Myeloid cell-specific PD-1 ablation induced an increase of T effector memory cells with improved functionality and mediated antitumor protection despite preserved PD-1 expression in T cells. In PD-1-deficient myeloid progenitors, growth factors driving emergency myelopoiesis induced increased metabolic intermediates of glycolysis, pentose phosphate pathway, and TCA cycle but, most prominently, elevated cholesterol. Because cholesterol is required for differentiation of inflammatory macrophages and DC and promotes antigen-presenting function, our findings indicate that metabolic reprogramming of emergency myelopoiesis and differentiation of effector myeloid cells might be a key mechanism of antitumor immunity mediated by PD-1 blockade.