TPLEX, or T-Cell Receptor (TCR) Peptide Library Exchange, is a method used in immunology to study how T-cells recognize and respond to various peptides. This technique allows researchers to create a diverse library of peptide sequences that can be presented to T-cells, helping to identify which peptides trigger immune responses. By utilizing TPLEX, scientists can better understand the interactions between T-cells and antigens, which are substances that provoke an immune response. This knowledge is crucial for developing new vaccines and therapies for diseases, including cancer and autoimmune disorders.