CD27CD70

CD27-CD70 refers to a receptor-ligand axis in the tumor necrosis factor receptor superfamily that provides important costimulatory signals to cells of the immune system. CD27 is a membrane receptor of the TNFRSF7 family expressed on T cells, subsets of B cells, and natural killer cells. CD70 is its ligand, a transmembrane protein of the TNF ligand family whose expression is induced on activated antigen-presenting cells, certain activated lymphocytes, and some tumor cells.

Engagement of CD27 by CD70 delivers signals that promote T cell activation, proliferation, survival, and differentiation, particularly supporting CD8+ T cell responses and the formation of memory. It also enhances B cell responses and antibody production, in part through help from T follicular helper cells. Signaling through CD27 activates intracellular pathways including NF-κB, MAPK, and PI3K-Akt, leading to increased cytokine production and extended cell longevity.

Expression patterns and roles in immunity: the CD27-CD70 axis shapes adaptive responses during infections and vaccination by boosting cytotoxic T cell expansion and durability. NK cell activity can be enhanced through CD27 signaling, and B cell activation and class switching can be influenced indirectly. Abnormal or sustained CD70 expression on tumor cells or dendritic cells can affect immune surveillance and has motivated research into targeted therapies.

Clinical relevance: the CD27-CD70 axis is an area of active immunotherapy research. Approaches include the use of agonistic antibodies to stimulate anti-tumor T cell activity and strategies to block CD70 to reduce excessive or misdirected immune activation in autoimmune conditions. Therapeutic development emphasizes balancing potent immune activation with safety considerations to minimize inflammatory side effects.