“I mentioned, ‘I’m an RNA scientist. I can do something with RNA,’” Dr. Karikó recalled telling Dr. Weissman. He requested her: May you make an H.I.V. vaccine?
“Oh yeah, oh yeah, I can do it,” Dr. Karikó mentioned.
As much as that time, business vaccines had carried modified viruses or items of them into the physique to coach the immune system to assault invading microbes. An mRNA vaccine would as a substitute carry directions — encoded in mRNA — that will permit the physique’s cells to pump out their very own viral proteins. This strategy, Dr. Weissman thought, would higher mimic an actual an infection and immediate a extra sturdy immune response than conventional vaccines did.
It was a fringe concept that few scientists thought would work. A molecule as fragile as mRNA appeared an unlikely vaccine candidate. Grant reviewers weren’t impressed, both. His lab needed to run on seed cash that the college offers new school members to get began.
By that point, it was simple to synthesize mRNA within the lab to encode any protein. Drs. Weissman and Karikó inserted mRNA molecules into human cells rising in petri dishes and, as anticipated, the mRNA instructed the cells to make particular proteins. However after they injected mRNA into mice, the animals bought sick.
“Their fur bought ruffled, they hunched up, they stopped consuming, they stopped working,” Dr. Weissman mentioned. “No one knew why.”
For seven years, the pair studied the workings of mRNA. Numerous experiments failed. They wandered down one blind alley after one other. Their drawback was that the immune system sees mRNA as a chunk of an invading pathogen and assaults it, making the animals sick whereas destroying the mRNA.
Finally, they solved the thriller. The researchers found that cells defend their very own mRNA with a selected chemical modification. So the scientists tried making the identical change to mRNA made within the lab earlier than injecting it into cells. It labored: The mRNA was taken up by cells with out frightening an immune response.