Georg Kohler and Cesar Milstein physically fuse mouse lymphocytes with neoplastic mouse plasma cells to yield hybrid cells called hybridomas that can produce specific antibodies and survive indefinitely in tissue culture. This approach offers a limitless supply of monoclonal antibodies. Monoclonal antibodies permit the generation of diagnostic tests that are highly specific. They also function as probes to study cell function. With Jerne, Kohler and Milstein are awarded the Nobel Prize in Medicine or Physiology in 1984.