[JPLeRouzic]

> kick off an immune response that gets those cells killed.

I am not a scientist but I was to ask if this was the case for every vaccine, yet I reflected that no in pre-mRNA vaccines the principle is different: You body cells are not primed to produce an antigen. The antigen is brought externally and T-cells recognize it. They kill only infected cells.

If I understand correctly in mRNA vaccines, all cells produce the antigen (the spike protein) so they are indiscriminately killed by T-cells.

Is my understanding correct?

[jagraff]

There are plenty of vaccines that use attenuated viruses - these also force your cells to produce antigens, and in fact the virus reproduces in your cells and damages them on its own as well. You could think of an mRNA vaccine as kind of like an attenuated virus vaccine, except for the fact that it can’t reproduce itself at all, unlike a virus.

[etiam]

JPLeRouzic's point about indiscriminate expression is significant though.

The tiny lipid bubbles used to introduce the (recent mRNA-)vaccines should introduce foreign nucleic acids (RNA,DNA) just on the basis of there being a cell membrane to merge into, whereas virions ('virus particles'), attenuated strain or not, would typically (always?) co-opt some receptor or other trans-membrane molecule, other than the membrane phospholipids, to aid their introduction of foreign nucleic acids.

In other words, the virions are at least somewhat restricted/targeted in what cell types they enter, and in many cases even the susceptible cells can in principle affect their level of susceptibility by regulating how much of those co-opted molecules are created, or allowed to be transported to the surface. (Innate immune response includes cells generally becoming more wary about how they transport materials and metabolize molecules we might describe as carrying information)

So it's a prefectly good description, in my opinion, that

> [for these] mRNA vaccines, all cells produce the antigen (the spike protein) so they are indiscriminately killed by T-cells.

although there are indeed aspects which are similar with live vaccines.

[JPLeRouzic]

Thanks I was not aware of that

[shagie]

There's a good page on how the traditional flu vaccines are made at https://www.cdc.gov/flu/prevent/how-fluvaccine-made.htm

One of the "this is concerning" things with the traditional chicken egg based version is that they are chicken eggs.

https://www.cnn.com/2020/03/27/health/chicken-egg-flu-vaccin... and an amusing video on it from Half as Interesting - https://youtu.be/F0qD5argOHE

The corresponding part is that they are chickens and you've likely heard about the price of eggs recently ( https://arstechnica.com/science/2023/01/as-egg-prices-soar-t... ).

There is good reason to be looking at alternative ways to creating vaccines.

[phkahler]

There is in fact a conventional vaccine for Covid, but most people are not aware nor do we have access to it. The inventors did not patent it but made it a gift to the world. Buy hey, money and "do as I say". Oh it's called Corbevax.

[JPLeRouzic]

Thanks, but it came late in the game (end of 2021).

I think there was also a open source Covid vaccine from MIT but I can't find a reference.