The Roles of CD8+ T Cell Subsets in Antitumor Immunity

There are multiple subsets of CD8+ T cells, not all of which have cytotoxic function and produce IFN-γ. A variety of Tc subsets have been detected within the TME and, depending on the subset, can be either positively or negatively correlated with prognosis. In the context of adoptive immunotherapy to treat cancer, the degree of tumor control is greatly influenced by the subset of T cells transferred. Effector CD8+ T cells are typically thought to be a homogenous group of cytotoxic cells that produce interferon-(IFN) γ. However, recent findings have challenged this notion because multiple subsets of CD8+ T cells have been described, each with distinct effector functions and cytotoxic potential. These subsets, referred to as the Tc subsets, have also been detected in tumor microenvironments (TMEs), where they potentially influence the antitumor response and patient outcomes. In this review, we highlight the prevalence and roles of Tc subsets in the TME. We also discuss their therapeutic applications in the context of adoptive immunotherapy to treat cancer. Effector CD8+ T cells are typically thought to be a homogenous group of cytotoxic cells that produce interferon-(IFN) γ. However, recent findings have challenged this notion because multiple subsets of CD8+ T cells have been described, each with distinct effector functions and cytotoxic potential. These subsets, referred to as the Tc subsets, have also been detected in tumor microenvironments (TMEs), where they potentially influence the antitumor response and patient outcomes. In this review, we highlight the prevalence and roles of Tc subsets in the TME. We also discuss their therapeutic applications in the context of adoptive immunotherapy to treat cancer.