Lysosome function in antigen-presenting cell

Lysosomes are membrane-bound organelles within antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B lymphocytes. They play a **critical role in the degradation of internalized antigens**—whether from pathogens or other sources—by breaking them down into peptide fragments. These peptides are then loaded onto major histocompatibility complex class II (MHC-II) molecules within the endo/lysosomal compartment before being presented on the cell surface for recognition by CD4+ T cells[1][2][5]. In some cross-presentation pathways, lysosomes also contribute to loading peptides onto MHC-I molecules[2]. Lysosome function is tightly regulated during immune responses. For example, upon stimulation with signals like lipopolysaccharide (LPS), lysosomes undergo morphological changes such as tubulation and expansion via mTOR-dependent pathways; this enhances their capacity for antigen processing and presentation[4][5][7]. The positioning of lysosomes within APCs is dynamically controlled to optimize phagocytosis and subsequent antigen presentation[5]. Dysregulation of lysosome function can impact immunity—for instance, excessive leakage can trigger inflammasome activation and inflammatory cell death[2], while altered trafficking may affect efficiency of antigen presentation. **Note:** "Lysosome function in antigen-presenting cells" refers to an organelle's activity rather than a discrete molecular target like a receptor or enzyme. It is not considered a canonical therapeutic target but rather describes an essential cellular process involving multiple proteins and regulatory mechanisms. Therefore, it does not fit standard drug-target classification schemes used for receptors or enzymes.

Other names

Lysosomal function in APCLysosome-mediated antigen processingEndo-lysosomal system in immune cells