Immunostimulatory receptors

Immunostimulatory receptors, also known as co-stimulatory receptors, are a functional class of cell surface proteins that provide essential secondary signals for the activation, differentiation, and survival of immune cells, particularly T lymphocytes (Nature Reviews Drug Discovery, 2019). These receptors are broadly categorized into two main structural families: the Tumor Necrosis Factor Receptor Superfamily (TNFRSF), which includes targets like 4-1BB (CD137), OX40 (CD134), CD27, and GITR; and the Immunoglobulin Superfamily (IgSF), which includes CD28 and ICOS (Frontiers in Immunology, 2020). In the context of oncology, these receptors function as accelerators of the immune response, working in tandem with primary T-cell receptor (TCR) signaling to promote robust anti-tumor activity (Journal of Hematology & Oncology, 2021). Therapeutic targeting of these receptors typically involves the use of agonistic monoclonal antibodies designed to mimic natural ligands and trigger downstream signaling pathways, such as NF-κB or PI3K/Akt (Clinical Cancer Research, 2018). While drugs like urelumab (targeting 4-1BB) and selicrelumab (targeting CD40) have shown potent preclinical activity, their clinical utility has been constrained by narrow therapeutic windows and significant safety concerns, most notably hepatotoxicity and cytokine release syndrome (Nature Reviews Clinical Oncology, 2022). Current drug development strategies are focused on improving the specificity and safety of these agonists through the use of bispecific antibodies, such as those targeting both a co-stimulatory receptor and a tumor-associated antigen, to localize immune activation to the tumor microenvironment (Cancer Discovery, 2023).

Other names

Co-stimulatory receptorsImmune agonist receptorsT-cell co-stimulatory moleculesPositive immune checkpoints

Agonism of co-stimulatory signaling pathways to enhance T-cell activation, proliferation, and survival.