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Ageing as an interpretation for the non-proliferation of cells in culture


Fulfilling Koch's postulates
Leonard Hayflick Scientist
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When we were working with Mycoplasma pneumoniae, we needed to do something called fulfilling Koch's postulates. Robert Koch, a German scientist, established some principles in respect to how you prove that a disease is caused by a particular agent and his rules went something like this. Of course, you must isolate the agent and identify it first, then you must inoculate it into an appropriate animal and this, in some cases, as with pneumoniae, a human, and then you must prove that disease is produced and then you must isolate the organism from the disease and prove that you have the same organism. Those are Koch's postulates.

So, Bob Chanock and I had an opportunity to do this because in that era, there were, at the Political Centre in Bethesda, prisoner quote volunteers end quote; federal prisoner volunteers on whom experiments were done. In our case, it was not a serious breach of any ethical consideration in my judgement because what we did was to take the culture that I had discovered, grow up the mycoplasmas in a solution and instil it into the nares, into the nose of prisoner volunteers, hoping to reproduce primary atypical pneumonia. Now, that wasn't a fatal disease if indeed the prisoners came down with it because we could treat it immediately with antibiotics and that would be the end of it.

It turned out that the culture that... my culture was negative; it did not produce the disease. After I had by this time isolated a fresh culture of Mycoplasma pneumoniae from a patient at the University of Pennsylvania and grew that up, that one did produce disease. The reason the first one failed is a very well known phenomenon and that is when a microorganism with... that produces some pathogenicity is passaged many, many times as this agent had been by Monroe Eaton and Bob Chanock, that it will lose its disease-producing capability. And apparently that's what happened.

So, my strain, although it has been deposited in a central repository for microorganisms in the United States called the American Type Culture Collection and in the United Kingdom and Germany and several other countries, that strain did not produce disease for the reasons that I mentioned. And so, the ethical considerations, as you can see, were quite different. No committee approval was required as is required today.

Leonard Hayflick (b. 1928), the recipient of several research prizes and awards, including the 1991 Sandoz Prize for Gerontological Research, is known for his research in cell biology, virus vaccine development, and mycoplasmology. He also has studied the ageing process for more than thirty years. Hayflick is known for discovering that human cells divide for a limited number of times in vitro (refuting the contention by Alexis Carrel that normal body cells are immortal), which is known as the Hayflick limit, as well as developing the first normal human diploid cell strains for studies on human ageing and for research use throughout the world. He also made the first oral polio vaccine produced in a continuously propogated cell strain - work which contributed to significant virus vaccine development.

Listeners: Christopher Sykes

Christopher Sykes is a London-based television producer and director who has made a number of documentary films for BBC TV, Channel 4 and PBS.

Tags: Mycoplasma pneumoniae, Robert Koch

Duration: 3 minutes, 16 seconds

Date story recorded: July 2011

Date story went live: 08 August 2012