Peptides are small proteins. They can be produced chemically in quantities of many kilograms. RAS peptides are very stable and can be stored for several years.
T cells are cells of the immune system that defend the host against intracellular changes and infections. By using peptides mimicking special intracellular changes, like RAS mutations, a subset of T cells can be induced that recognizes cells with such mutations and triggers immunological eradication of these cells. T cells also provide immunological memory and are rapidly retriggered upon reappearance of cells with the specific intracellular changes.