Jason McLellan
Structural biologist at the University of Texas at Austin.
Jason McLellan is famous for saying that the spike protein encoded by the mRNA vaccines is tethered to the surface of the cell and is not secreted and thus does not float through the body.
I think discovering the mutations that stabilize the pre-fusion conformations of coronaviral spike proteins used in the vaccines is a tiny bit more that just "doing your part." Congratulations, and thank you!
— navin.pokala@threads navinpokala@bsky (@NavinPokala) March 25, 2021
Made the following statements:
“The spike protein is not pathogenic. It is not a toxin.”
The spike proteins from the virus and the ones generated by the vaccines are “essentially the same,” McLellan, the spike protein researcher at the University of Texas at Austin, said, noting that they have the same function, structure and way of processing.
But, he added, there is “one key difference,” in that the spikes encoded by the vaccines “contain 2 amino acid changes that help stabilize the spike in its initial conformation and help prevent the spike from undergoing a conformational change that is required to facilitate membrane fusion.”
While previously working on a vaccine for MERS, a disease caused by another coronavirus, McLellan and others discovered that by adding two proline molecules to the spike protein, they could lock it into its pre-fusion state, triggering a more effective immune response and preventing cell entry. The same harmless mutation, called 2P, as in two proline molecules, is used in the SARS-CoV-2 vaccines.
My first physical involvement in some #SARSCoV2 work today – in vivo RNA transfection started (to be fair, performed by others). Shout-out to @McLellan_Lab and colleagues for developing the stabilized Spike construct used – many thanks from one virologist to another! pic.twitter.com/lDiLiibvMl
— Ben Hale (@BenHalePhD) June 8, 2021
With the live virus, the protein “attaches to receptors on the surface of cells and fuses the viral membrane with the host-cell membrane,” McLellan said.
Vaccine-generated spike proteins, however, can’t do that fusion because they are locked in the pre-fusion shape.
“The spike protein encoded by the mRNA vaccines (Moderna and Pfizer/BioNTech) and the J&J vaccine instruct the cells in our arm (where the injection is given) to produce spike protein that is tethered to the surface of the cell. It is not secreted and thus does not float through the body,” McLellan said.
Thank you for engineering the spike protein!!!!
— Cory Inman (@IM_Inman) March 25, 2021