Leitz Inverted Microscope, Circa 1958

Credit: COURTESY OF TERRY SHARRER When Leonard Hayflick began his cell culture work at the Wistar Institute in the 1950s, the field was facing a nagging problem. Culture flasks were so big, that microscope objective lenses couldn't come reasonably close to the subject. Hayflick told his Leitz sales representative about the problem, and the sales rep returned with an inverted chemist's microscope popular among crystallographers. With slight modifi

By | March 1, 2007

<figcaption> Credit: COURTESY OF TERRY SHARRER</figcaption>
Credit: COURTESY OF TERRY SHARRER

When Leonard Hayflick began his cell culture work at the Wistar Institute in the 1950s, the field was facing a nagging problem. Culture flasks were so big, that microscope objective lenses couldn't come reasonably close to the subject. Hayflick told his Leitz sales representative about the problem, and the sales rep returned with an inverted chemist's microscope popular among crystallographers. With slight modification, it became a workhorse for cell culture work.

Hayflick, now professor of anatomy at the University of California, San Francisco, used the microscope for three major career achievements: the discovery of Mycoplasma pneumoniae,1 the determination that normal human diploid cells undergo a limited number of doublings,2 and the development of a vaccine-producing cell strain, "WI-38."3

By isolating Mycoplasma, Hayflick advanced the sorting out of bacterial and viral pathogens for pneumonia and influenza, which together had been the leading cause of death in the United States before 1950.

Hayflick and colleague Paul Moorhead showed that normal embryonic human diploid cells become quiescent and eventually die after about fifty population doublings. This observation overturned Alexis Carrel's half century-old assertion that any cell could be kept alive indefinitely in vitro. The so-called Hayflick limit first defined aging at the cellular level and led later investigators to the telomere and telomerase.

WI-38, from an elected abortus in Sweden, became the preferred producer strain for virtually all human virus vaccines. The primary WI-38 culture held potential for yielding twenty million metric tons of material in its fifty population doublings. At least one-sixth of humanity has had artificial immunizations grown in WI-38.

References

1. R.M. Chanock et al., "Growth on artificial medium of an agent associated with atypical pneumonia," Proc Natl Acad Sci, 48:41?9, 1962. 2. L. Hayflick, P.S. Moorhead, "The serial cultivation of human diploid cell strains," Exp Cell Res, 26:585?621, 1961. 3. L. Hayflick et al., "Preparation of poliovirus vaccines in a human fetal diploid cell strain," Am J Hygiene, 75:240?58, 1962.

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