Antigen-presenting immune system

The antigen-presenting immune system is a coordinated biological process involving specialized cells that capture, process, and display antigens to T-lymphocytes to trigger adaptive immunity (StatPearls, 2023). This system relies on professional antigen-presenting cells (APCs), such as dendritic cells and macrophages, which utilize Major Histocompatibility Complex (MHC) Class I and II molecules to present peptide fragments (NIH, 2022). While the term describes a physiological pathway rather than a single molecular entity, its individual components—such as MHC proteins and co-stimulatory molecules like CD80 and CD86—are major therapeutic targets (Nature Reviews Drug Discovery, 2020). In cancer therapy, drugs aim to enhance this system's efficiency to improve tumor recognition, while in transplantation and autoimmunity, therapies like abatacept work by blocking the co-stimulatory signals within this system (PubChem, 2024). Because it encompasses a wide array of cell types and diverse molecular interactions, it is classified as a biological system rather than a discrete drug target.

Other names

Antigen presentation pathwayProfessional antigen-presenting cellsAPC systemMHC-mediated antigen presentation

Modulation of the immunological synapse between antigen-presenting cells and T-cells, primarily through the regulation of MHC-peptide complexes and co-stimulatory or co-inhibitory signals (Nature Reviews Drug Discovery, 2020).