[Antitumor Immunity Evaluated via the Peripheral Blood].

ABSTRACT

Cancer immune-editing, and cancer immunity cycle theories are fundamental to tell how antitumor T-cell immunity is born and mediate antitumor reactivity. Recent studies have demonstrated that not only CD8+ T cells but also CD4+ T cells are required to establish antitumor immunity and revealed phenotypes in detail and clonotypes of T cells that play critical roles in these theories. It has been also demonstrated that antitumor CD8+ T cell clones or antitumor CD4+ T cell clusters more widely spread than we imagined and could be found everywhere including in the peripheral blood. The peripheral blood circulation is the way to deliver specific antitumor T cells, which are primed and expand clonally in the secondary lymphoid organs. Migration and invasion through the peripheral blood is one of the 7 steps of cancer immunity cycle theory. We will discuss antitumor immunity from the landscape via the peripheral blood, based on the mechanisms how anti-PD-1/PD- L1 Ab and anti-CTLA-4 Ab work.