The role of receptor programmed death-1 and its ligands in immune system and tumors

Abstract

programmed death-1 (pD-1) molecule is an immunoreceptor, which is inducibly expressed on both T and B lymphocytes. pD-1 is a negative regulator of the immune response. Through interactions with its ligands: pD-L1 and pD-L2, being expressed on wide range of tissue, pD-1 is responsible for maintenance of peripheral tolerance by restricting activation, proliferation and effector functions of T lymphocytes. Aberrations of the pD-1/pD-L pathway lead to autoimmune disorders and are observed on exhausted lymphocytes during chronic infections. Expression of pD-1 and its ligands is described in many tumor entities, where it modulates tumor microenviroment and might be a potential escape mechanism from immunosurveillance. There are growing evidences for potential therapeutical applications of the pD-1/pD-L pathway, including heamatological malignances.