Dr. Leonard Hayflick 

Hayflick Items Accessioned by the Smithsonian Institution History of Science Section 

In the late 1950’s when cell culture became popular, ordinary light microscopes were incapable of allowing the viewing cells through the thick glass vessels then used. Leonard Hayflick, Ph.D. and a Founding Member of the Council of the National Institute on Aging, now at The University of California, San Francisco, modified a crystallographer’s inverted microscope that overcame this problem. It is the grandfather of all inverted microscopes now in use by cell culturists globally and has been accessioned by the Smithsonian Institution History of Science Section.

Dr. Hayflick’s microscope that was recently acquired by the Smithsonian 

 In 1961 Hayflick overturned a sixty year old dogma claiming that all cultured cells had the capacity to be cultured indefinitely. Hayflick found that normal human cells had a finite replicative capacity in vitro and was therefore able to show that only cancer cells were immortal. He interpreted his discovery to be aging or senescence at the cell level. This finding has now been shown to occur in vivo and the large field of “Senolytics” has emerged where efforts to remove these cells in old individuals is the goal.  

Left: Box of Pfizer’s “Diplovax” Sabin Poliomyelitis Vaccine made in WI-38 Hayflick; Right: original WI-38 glass ampoules. Both were accessioned by the Smithsonian Institution, History of Science Section.

 Hayflick also found that his normal human cell strain, WI-38, grew all of the then known human viruses and that it was superior to the dangerous primary monkey kidney cells then in use for poliovirus vaccine production. He developed the first polio vaccine grown in normal human cells and gifted WI-38 to the developers of the rubella and rabies vaccines. In addition to the manufacturers of these two vaccines he gifted WI-38 to all commercial vaccine manufacturers world-wide including makers of those against measles, mumps, rubella, varicella (chicken pox), herpes zoster, adenovirus, rabies and Hepatitis A. In the U.S. the estimated number of cases averted with WI-38 grown vaccines from 1960–2015 was 198 million and 4.5 billion globally. The total number of deaths averted from these diseases was approximately 450,000 in the U.S. and 10.3 million globally. Ampules of WI-38 and photos of Pfizer’s Diplovax showing containers of Sabin’s polio vaccine, labeled as produced in WI-38 Hayflick. have been accessioned by the Smithsonian Institution History of Science Section. Images of these items can be found on the Smithsonian website.

Submitted by
Leonard Hayflick, Ph.D

Professor of Anatomy 
University of California, San Francisco 

Read Dr. Hayflick’s paper
“The Role of the WI-38 Cell Strain in Saving Lives and Reducing Morbidity.”

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