T cell and antigen-presenting cell immune pathway

The T cell and antigen-presenting cell (APC) immune pathway represents the fundamental interface of the adaptive immune system, where APCs like dendritic cells and macrophages present processed antigens to T lymphocytes (Gaudino & Kumar, 2023). This interaction occurs at the immune synapse and requires two primary signals: the recognition of an antigen-MHC complex by the T cell receptor (TCR) and a secondary costimulatory signal, such as the binding of CD28 to CD80/86 (Janeway et al., 2001; Sharpe & Freeman, 2002). These pathways are essential for initiating immune responses against pathogens and tumors, but their dysregulation can lead to chronic inflammation or autoimmunity. In oncology, these pathways are often exploited by tumors through immune checkpoints like PD-1/PD-L1 and CTLA-4, which act as inhibitory signals to dampen T cell activity (Pardoll, 2012). Pharmacological modulation of these pathways includes the use of checkpoint inhibitors to enhance anti-tumor responses or costimulation blockers like abatacept to treat autoimmune conditions (StatPearls, 2023). Because this term encompasses a broad set of biological processes and multiple distinct molecular targets, it is classified as a pathway rather than a single therapeutic target.

Other names

T cell-APC interactionImmune synapseAntigen presentation and T cell activation pathwayT cell costimulation pathway

Checkpoint inhibition, costimulation blockade, and T cell receptor signaling modulation.