Science / Origin Story

The Tangled History of mRNA Vaccines

Hundreds of scientists had worked on mRNA vaccines for decades before the coronavirus pandemic brought a breakthrough.

by Elie Dolgin via Nature on September 14, 2021

...generosity, curiosity and dogged persistence against scepticism and doubt. “It’s a long series of steps,” says Paul Krieg, a developmental biologist at the University of Arizona in Tucson, who made his own contribution in the mid-1980s, “and you never know what’s going to be useful”.

The beginnings of mRNA

Malone’s experiments didn’t come out of the blue. As far back as 1978, scientists had used fatty membrane structures called liposomes to transport mRNA into mouse3 and human4cells to induce protein expression. The liposomes packaged and protected the mRNA and then fused with cell membranes to deliver the genetic material into cells. These experiments themselves built on years of work with liposomes and with mRNA; both were discovered in the 1960s (see ‘The history of mRNA vaccines’).

Back then, however, few researchers were thinking about mRNA as a medical product — not least because there was not yet a way to manufacture the genetic material in a laboratory. Instead, they hoped to use it to interrogate basic molecular processes. Most scientists repurposed mRNA from rabbit blood, cultured mouse cells or some other animal source.

That changed in 1984, when Krieg and other members of a team led by developmental biologist Douglas Melton and molecular biologists Tom Maniatis and Michael Green at Harvard University in Cambridge, Massachusetts, used an RNA-synthesis enzyme (taken from a virus) and other tools to produce biologically active mRNA in the lab5 — a method that, at its core, remains in use today. Krieg then injected the lab-made mRNA into frog eggs, and showed that it worked just like the real thing6.

Both Melton and Krieg say they saw synthetic mRNA mainly as a research tool for studying gene function and activity. In 1987, after Melton found that the mRNA could be used both to activate and to prevent protein production, he helped to form a company called Oligogen (later renamed Gilead Sciences in Foster City, California) to explore ways to use synthetic RNA to block the expression of target genes — with an eye to treating disease. Vaccines weren’t on the mind of anyone in his lab, or their collaborators.

“RNA in general had a reputation for unbelievable instability,” says Krieg. “Everything around RNA was cloaked in caution.” That might explain why Harvard’s technology-development office elected not to patent the group’s RNA-synthesis approach. Instead, the Harvard researchers simply gave their reagents to Promega Corporation, a lab-supplies company in Madison, Wisconsin, which made the RNA-synthesis tools available to researchers. They received modest royalties and a case of Veuve Clicquot Champagne in return.