Sir John Mitchison was a prominent British biologist known for his significant contributions to the field of immunology. He was born on March 12, 1919, and became a key figure in understanding how the immune system functions. His research helped lay the groundwork for advancements in medical science, particularly in the development of vaccines and treatments for various diseases. In addition to his research, Mitchison served as a professor at University College London and held various leadership roles in scientific organizations. He was recognized for his work with numerous awards, including a knighthood in 1986, reflecting his impact on both science and society.