Killer Cells and Cancer

The idea that the immune system could specifically recognize and respond to tumors was a major driving force in the early development of immunology. This hope arose in part from thoughts put forward by Paul Ehrlich (1909), and from the early observation that tumors passed from one outbred mouse to another did not survive. But Peter Gorer put the idea that rejection under these conditions had anything to do with the tumor nature of the transplant to rest in the 1930s, when he showed this was simply an example of allograft rejection. Subsequent research focused largely on the genetics and immunology of allograft reactions, and, together with advances in immunosuppression, would eventually lead to clinical transplantation of tissues and organs in humans. It also led, as we have seen, to the discovery of killer lymphocytes. Tumor immunology per se was pushed onto the back burner for nearly twenty years after Gorer’s experiments. It was brought forward again by observations beginning in the 1950s that the immune system can indeed recognize something specific about tumors within the animal in which they arise, and mount a response that not only destroys the tumor, but renders the host resistant to future challenges with the same tumor.