Activating receptors on antigen-presenting immune cells

Activating receptors on antigen-presenting immune cells (APCs), such as dendritic cells, macrophages, and B cells, are a functional group of proteins that drive the maturation and activation of the immune system (Wikipedia, 2024). This category primarily includes the tumor necrosis factor receptor (TNFR) superfamily member CD40 and various pattern recognition receptors (PRRs) like Toll-like receptors (TLRs) and the Stimulator of Interferon Genes (STING) (NIH, 2023). When these receptors are engaged by their ligands, they trigger intracellular signaling pathways that lead to the upregulation of major histocompatibility complex (MHC) molecules and co-stimulatory ligands such as CD80 and CD86 (Frontiers in Immunology, 2021). This process, often referred to as APC licensing, is essential for the effective priming and activation of naive T cells into effector cells (Nature Reviews Drug Discovery, 2020). In the context of cancer immunotherapy, agonists targeting these receptors, such as CD40-agonistic antibodies (e.g., selicrelumab) or TLR agonists (e.g., imiquimod), are used to enhance the body's ability to recognize and attack malignant cells (PubMed, 2022). These therapies aim to overcome the immunosuppressive tumor microenvironment by promoting antigen cross-presentation and cytokine production (Journal of Clinical Investigation, 2021). However, the potent immune activation induced by these agents can lead to significant safety concerns, including cytokine release syndrome, systemic inflammation, and hepatotoxicity (StatPearls, 2023). Therapeutic challenges also include the need for precise dosing to avoid immune exhaustion or systemic toxicity (Cell, 2022). Overall, these receptors represent a critical bridge between innate and adaptive immunity and are key targets for next-generation immunotherapies.

Other names

APC activating receptorsCo-stimulatory receptors on APCsPattern recognition receptors on APCsCD40Toll-like receptors (TLRs)STING (Stimulator of Interferon Genes)Activating Fc gamma receptorsC-type lectin receptors

Agonism of receptors on antigen-presenting cells to induce maturation, cytokine production, and enhanced T-cell priming.