Immune regulation by CD8^(+) Treg cells:novel possibilities for anticancer immunotherapy

摘要

Regulatory T(Treg)cells comprise diverse subsets of immunosuppressive cells that play a pivotal role in regulating immune homeostasis and preventing autoimmunity.In cancers,Treg cells can suppress antitumor immune responses and support the establishment of an immunosuppressive tumor micro-environment,thus promoting immune evasion and cancer progression.1 Treg cells are increased or activated in the tumor microenvironment,which is associated with a poor clinical outcome.2 Although CD4^(+)Treg cells have been extensively studied,the lack of universal markers to distinguish CD8^(+)Treg cells from conventional CD8^(+)T cells means that the function of CD8^(+)Treg cells in cancer has not been fully characterized.Now,an increasing body of research has revealed that CD8^(+)Treg cells(CD8^(+)CD25^(+)Foxp3^(+),CD25^(+)CD122^(+)Foxp3^(+)and CD8^(+)CD28−)3–5 accumulate in the tumor microenvironment and suppress antitumor immunity(Fig.1).However,the influence of CD8^(+)Treg cells on tumor progression in ovarian cancer(OC)is less clear.Moreover,there are a limited number of studies describing the molecular signatures involved in the induction of CD8^(+)Treg cells.