Antigen-expressing target cell

The term "Antigen-expressing target cell" appears to be a misnomer or non-standard reference likely intending "antigen-presenting cell" (APC), a critical class of immune cells including dendritic cells, macrophages, and B cells that process foreign or abnormal antigens and display them on major histocompatibility complex (MHC) molecules to activate T cells. These cells engulf pathogens or debris via phagocytosis or endocytosis, degrade them into peptides in lysosomes or proteasomes, and present the peptides on MHC class I (for CD8+ cytotoxic T cells) or MHC class II (for CD4+ helper T cells), often with co-stimulatory signals to ensure specific adaptive immune responses against infections, tumors, or abnormal cells. Dendritic cells are the most potent professional APCs, excelling in naive T cell priming and cross-presentation, while macrophages sustain responses in tissues and B cells link humoral immunity by presenting antigens bound to their receptors. In disease, APCs drive anti-tumor immunity by presenting cancer antigens but can contribute to autoimmunity if tolerance mechanisms fail; they are not a single molecular receptor, enzyme, or druggable target but a functional cell category exploited in immunotherapies like dendritic cell vaccines. This broad cell-based entity lacks a specific protein structure for direct pharmacologic modulation, distinguishing it from typical therapeutic targets like receptors or enzymes.

Other names

Antigen-presenting cell (APC)accessory cell