Posts Tagged HeLa
I just finished reading Jonas Salk, A Life, by Charlotte DeCroes Jacobs, published in 2015 by Oxford University Press. Here’s my take on the book and the main character.
Jonas Salk was born on October 28, 1914 in a tenement in East Harlem, New York. His mother was a Russian immigrant, his father a natural-born American of Lithuanian ancestry. He was intelligent and eager to learn, prodded both by his strong-willed mother and his innate desire to learn. He was quite intelligent in fact—he skipped several grades in school and went on to attend City College of New York and eventually University and Bellevue Medical College where he graduated with an MD degree in June, 1939. When World War II broke out, he was classified IIA (deferred in support of national health), and never actually served in the Army, though later he worked with the Army in testing an influenza vaccine. He’d gotten his first position at the University of Michigan in Ann Arbor where he began his work on an early influenza vaccine, an accomplishment he doesn’t very often get credit for. In fact, some of the techniques he devised in that study helped make the vaccine feasible.
Here Jacobs briefly reviews the history of vaccines, including Jenner’s smallpox vaccine, Pasteur’s rabies vaccine, and Max Theiler’s yellow fever vaccine. Salk’s influenza vaccine was a killed vaccine, made by inactivating the virus with formaldehyde.
In October of 1947, Salk moved to the University of Pittsburgh where he continued to work on influenza and where he tested it in Army recruits. It was here he started the work he’s best known for, an inactivated poliovirus vaccine. His name is so synonymous with the inactivated vaccine it’s even in the dictionary to this day. (Look under “Salk vaccine.”) By this time, polio was a worldwide scourge. Epidemics came around every few years when children (mostly) were cut down with fever, pain, and eventual paralysis. The paralysis could affect one or more limbs or the breathing muscles, requiring the child be hospitalized in a full-body respirator, better known as an iron lung. Deaths from the disease were common. Salk himself, though he grew up in a lower-class neighborhood of New York City, never caught either influenza or polio, thanks in large part to this mother who kept him inside studying more than many others of his generation.
Salk’s work on the polio vaccine was funded in large part by the National Foundation for Infantile Paralysis (NFIP). It had been started in 1937 by President Franklin Roosevelt (himself a polio survivor.) Interestingly, Jacobs reports that FDR attended a Boy Scout rally where he most likely became infected. I’d never heard that story, though she gives it without attribution, unusual in a book so full of references on all aspects of Salk’s life. Roosevelt picked Basil O’Connor to head up the NFIP, and O’Connor became one of Salk’s closest friends and allies for a long time, almost until his death. O’Connor got Salk the money he needed to do the work on the vaccine. It was the NFIP that started the “March of Dimes” program, though interestingly, entertainer Eddie Cantor was the one who actually coined the term. Salk continued to receive funding from the NFIP for many years, even though his founding of the Salk Foundation in La Jolla, California.
It’s instructive to look back on Jonas Salk’s work with the hindsight of history. I can state from my own experience that poliovirus is a relatively easy virus to grow and work with. Salk took advantage of the new science of cell culture, where living cells could be grown in a glass vessel such as a test tube or a flask. Viruses have to have living cells to grow in. One type of early culture cell was made from the kidneys of monkeys (a technique still in use, though not for making vaccines), and poliovirus grew easily in it. I’ve grown poliovirus in many different types of cells, including continuous cell lines such as HeLa, where it grows well. So it’s easy to see why polio was one of the first viruses used for vaccine production. Salk could get large amounts of it, and it could be titrated (measured) easily. He inactivated it with formalin (formaldehyde dissolved in water), which killed the virus but kept its ability to induce immunity in an individual. The techniques were there, and Salk took advantage of them. Ironically, it is for this probable reason that Jonas Salk was never inducted into the National Academy of Sciences in the US. His work on the inactivated vaccine, though a tremendous advance in the ongoing fight against infectious disease, may not have risen—in the eyes of the members of the Academy—to a level that met their guidelines of “distinguished . . . achievement in original research.” Salk was hurt, and carried his disappointment the rest of his life.
If there is a dark figure in Jonas Salk’s life, it would have to be Albert Sabin. Sabin criticized Salk beginning even before the inactivated vaccine came out. Sabin called him a “kitchen chemist.” “You could go,” he said, “into the kitchen and do what he did.” Sabin eventually developed a live-virus vaccine for polio, and it became the standard vaccine in the US (though not in all other countries), even though there have been reports of the live vaccine causing paralytic disease in some people. Sabin steadfastly refused to ever acknowledge this, however. Sabin took every opportunity to belittle Salk and his vaccine, promoting the live-virus vaccine whenever he could. It sounds like jealousy to me. Salk got the first vaccine against polio and the major share of the recognition.
On the dust jacket of the book is a picture of Salk holding a rack of about thirty test tubes. He’s holding the rack above his head and looking at the bottom of the tubes. While the picture was probably posed, he’s examining the tubes for something. Most probably he’s looking at the color of the liquid in the tubes. The liquid is a nutrient medium the monkey kidney cells grow in. If the medium is pink, it means the virus killed the cells, while yellow means the cells grew and were not infected. Behind him are many more racks, a testament to the huge amount of work it took to develop the vaccine.
Jonas Salk went on to work on AIDS and cancer, developing an early inactivated vaccine against AIDS. It didn’t work very well (actually, most vaccines against AIDS don’t work.) The Salk Foundation he set up in La Jolla continues to this day, and continues to try to work toward his vision of merging science and the humanities. That had been a life-long dream of his, though it didn’t work out exactly as he envisioned it. Salk was always a visionary, yet took no remuneration from his fame as the conqueror of polio. He worked almost entirely on the salary he drew from his academic appointments.
Many vaccines today are made from recombinant DNA which eliminates the need for inactivating a whole virus. The influenza vaccine, however, is still made of inactivated virus, still grown in embryonated hens eggs, using techniques that, though slightly changed from Salk’s day, would be familiar to him. Formaldehyde is now considered a carcinogen, and isn’t used any more. Monkey kidney cells can contain other viruses and these viruses can show up in a vaccine. But it’s interesting to look back at Jonas Salk and learn from his work. Poliomyelitis has been almost entirely eradicated from the earth, thanks in large part to the inactivated vaccine. Polio still exists in a few third-world countries, especially those torn by war. I suggest this book be required reading for any biological scientist, virologist or not, and undoubtedly will become the definitive account of Salk’s life. At least for a while.