Regulatory T cells in Tumor Immunity: Role of Toll-Like Receptors

This chapter discusses how the toll-like receptor (TLR) signaling is linked to the functional control of Tregs, and reviews the new tactics to improve cancer therapy by relieving the Treg-mediated suppression of antigen-specific antitumor immunity. An overview of the current understanding of Tregs and their regulation in cancer by innate immune cells and tumor-infiltrating dendritic cells (DCs) is also provided. Both macrophages and DCs function as major sensors for invading the pathogens and transformed tumor cells via a limited number of germ line-encoded pattern recognition receptors (PRRs)—known as TLRs—that play critical roles in modulating the inflammation and immune responses. Adaptive immunity is involved in the elimination of pathogens and transformed tumor cells in the late phase of the host defense, generating more specific immunity as well as immunological memory. A correlation exists between the level of tumor-infiltrating immune cells—particularly the CD8+ T cells, and the patient survival, while the presence of other immune cells like Tregs, confers a poor prognosis.