mRNA Vaccines

The Quarantine Zone
41

Sorry, but this is weak sauce. If you have the technical background, why haven’t you spent even half an hour looking at the easily accessible literature? I’m retired from the field, and not an immunology specialist myself, but it’s really not hard to find, and none of this stuff is behind paywalls.

The adjuvant question has been asked and extensively addressed in basic mRNA research long predating the COVID vaccines. Some extracts from this Nature review of mRNA vaccine technology dating to 2018.

https://www.nature.com/articles/nrd.2017.243

Some vaccine formulations contain novel adjuvants, while others elicit potent responses in the absence of known adjuvants…

Exogenous mRNA is inherently immunostimulatory, as it is recognized by a variety of cell surface, endosomal and cytosolic innate immune receptors [SEE FIGURE 1 IN THE REVIEW]… It is potentially advantageous for vaccination because in some cases it may provide adjuvant activity to drive dendritic cell (DC) maturation and thus elicit robust T and B cell immune responses…

The immunostimulatory properties of mRNA can conversely be increased by the inclusion of an adjuvant to increase the potency of some mRNA vaccine formats. These include traditional adjuvants as well as novel approaches that take advantage of the intrinsic immunogenicity of mRNA or its ability to encode immunemodulatory proteins. Self-replicating RNA vaccines have displayed increased immunogenicity and effectiveness after formulating the RNA in a cationic nanoemulsion based on the licensed MF59 (Novartis) adjuvant50. Another effective adjuvant strategy is TriMix, a combination of mRNAs encoding three immune activator proteins: CD70, CD40 ligand (CD40L) and constitutively active TLR4. TriMix mRNA augmented the immunogenicity of naked, unmodified, unpurified mRNA in multiple cancer vaccine studies and was particularly associated with increased DC maturation and cytotoxic T lymphocyte (CTL) responses (reviewed in REF. 51). The type of mRNA carrier and the size of the mRNA–carrier complex have also been shown to modulate the cytokine profile induced by mRNA delivery. For example, the RNActive (CureVac AG) vaccine platform52,53 depends on its carrier to provide adjuvant activity. In this case, the antigen is expressed from a naked, unmodified, sequenceoptimized mRNA, while the adjuvant activity is provided by co- delivered RNA complexed with protamine (a polycationic peptide), which acts via TLR7 signalling52,54. This vaccine format has elicited favourable immune responses in multiple preclinical animal studies for vaccination against cancer and infectious diseases18,36,55,56. A recent study provided mechanistic information on the adjuvanticity of RNActive vaccines in mice in vivo and human cells in vitro54. Potent activation of TLR7 (mouse and human) and TLR8 (human) and production of type I interferon, pro-inflammatory cytokines and chemokines after intradermal immunization was shown54. A similar adjuvant activity was also demonstrated in the context of non-mRNA-based vaccines using RNAdjuvant (CureVac AG), an unmodified, single-stranded RNA stabilized by a cationic carrier peptide57.

Also here:

On immuogenicity of RNA:

Extracellular RNA Sensing by Pattern Recognition Receptors | Journal of Innate Immunity | Karger Publishers
RNA sensors of the innate immune system and their detection of pathogens - PubMed

So the answer is that researchers have indeed been very concerned with the adjuvant question since the earliest stages of this technology, and many approaches have been tried, one of which has been the inclusion of traditional adjuvants with mRNA vaccines. But in many cases this has proven to be unnecessary, probably because of the intrinsic immunogenicity of RNA itself, and perhaps to some extent the particle coating.

In any event, coming back again to @tofor’s response - this is the most compelling answer, that the trials for these specific vaccines directly address the question your asking. Efficacy in eliciting a robust immune response, which is what the trials have demonstrated, is surely a diametrically opposite and mutually exclusive outcome to tolerance.

42

Personally, I’d probably let other people cut in front of me “in line” if i were 30 and didn’t have a history of getting sicker than average from the common cold. I’d still be planning to get vaccinated, but i would let those who were more worried/enthusiastic go first.

One of the problems with mRNA (and gene therapy in general) treatments for other disorders is that the immune system often decides that a novel protein is a problem, even if that novel protein is, for example, a clotting factor your body lacks. I do not have a relevant doctorate, and i don’t know what determines which way the immune system comes down.

The phase 1 (2? I can’t keep them straight) studies of the Moderna vaccine did look at what antibodies were being produced, and what sorts of t cells, etc.

I think one concern is that if the cells continued to spit out spike protein long enough, the immune system would eventually give up, but apparently mRNA breaks down on its own, and they don’t expect that to be a problem. But yeah, it’s a concern. I think it’s a larger concern with the DNA vaccines.

I’ve posted this link several times before, but you might find it reassuring.

Your want Lecture 10, “vaccines”

43

I’m not sure if the unusually aggressive response is due to my not explaining that I don’t believe that this should halt the rollout of this vaccine. I absolutely support the emergency approval of this vaccine, and I think that the high risk population should absolutely be getting this vaccine. If I didn’t state that, I apologize. My only concern here is that we do not know the long term effects of this RNA vaccine, or any RNA vaccine, in humans and that this needs to be studied in this first population of patients so that we can start to have long term data which we currently do not. Again, not faulting. It’s impossible to have long term data for something which has not existed for a long term.

Your review article citation only underscores this and demonstrates that this is a legitimate concern for RNA vaccines that should be considered for each new RNA vaccine. That this “has been asked and extensively addressed in basic mRNA research long predating the COVID vaccines” means this is an actual concern that needs to be addressed. In fact, the passage you are quoting above is outlining ways that should be considered to try to overcome this problem. Ways that are not being taken with this particular vaccine, which is relying on inherent immunogenecity. The fact that RNA vaccines can have an inherent immunogenicity has no bearing on whether THIS particular RNA vaccine has inherent immunogenicity, and what the immune system does with itself after the virus is cleared and the effector phase is over. We don’t have any data on the longevity of the RNA and the protein it encodes in humans. The protein is likely to outlast the RNA. Which means we will have COVID protein presentation in the absence of this still putative RNA immunogenicity at some point and for some duration of time.

The initial data is great. Much better than I expected. The effector immune response worked. The virus was cleared. My sole point is that we have no long term data on what the immune system does after that. Do some of the COVID spike protein specific T cells become memory Tregs? It sure would be nice to know and I hope that it’s being monitored in this first wave. We only have effector phase data right now.

And if we look at that data for this vaccine, and it looks great, I will still have the same issue with the next one and the one after that and the one after that until they have data for their particular vaccine. My issue wasn’t that nobody has brought up the issue of how RNA vaccines might tolerize the immune system. My issue is that nobody has brought it up for this vaccine. And seeing as how this is the first RNA vaccine we are putting in patients, all the mouse and in vitro data in the world (your second citation) is worth not a whole lot.

44

Watch the video I linked. It addresses many of your questions. But the tl;dr answer is, “yes, they have looked at those issues”

45

Most of the data presented is mice and non human primates. And all of it is still effector phase. I’m not concerned about the effector phase (at least not with this particular concern!). I’m concerned with the memory phase, for which there is not any data.

Again, so not to induce ire, no fault for that! There hasn’t been enough time to look at that in any real way, so there can’t be any data on that yet.

46

Let’s be clear, I was not responding to a non-scientist asking a question about something that had just occurred to them, which would be a very different matter.

You said you are an expert:

And, as an expert, you claimed to be raising an important issue that nobody else seemed to be concerned with:

I think you know that my response was far milder that you would have got in any scientific forum if you asserted that nobody in the field seem to be considering some major potential problem that you were now raising, when you don’t appear to have any familiarity with the literature. Spending even just a few minutes reading the literature leads you to dozens of papers and reviews, showing that people in the field have been very much focused on this issue and actively researching it for many years.

47

And I apologized for being unclear. I’m am quite familiar with the literature. I’m not familiar with any long term data obviating this issue, or anyone looking at it, for THIS vaccine because there currently isn’t any. There has not been a long term yet.

48

Do you disagree that in one individual, a robust adaptive immune response to an antigen and the induction of tolerance to that antigen are opposite and pretty much by definition mutually exclusive outcomes?

I would share your concern more if we were in the wishy-washy 50% efficacy type area. But don’t you think the robust adaptive response that we are measuring in these studies in the short term makes any notion of simultaneously inducing tolerance in the long term far more unlikely?

So aren’t the studies that we’re already doing directly addressing how THIS vaccine behaves in that respect?

49

I agree that most of the time, that is accurate.

Let me draw a situation that it might not be, which would be specific to an RNA vaccine. I get an RNA COVID vaccine. The cells at the injection site start making COVID protein. Within a few days, I have a nice population of adaptive B and T cells that recognize that protein. A week later I get infected with COVID. Lucky me, I have a population of cells primed to deal with it. They migrate to the site of infection in the lungs and encounter a few infected cells, in a danger context due to the virus killing some cells there. But, they dispatch it. Problem solved. I’m a win on the short term clinical trial.

Those T cells are still in circulation, and they are migrating throughout the body. They migrate to the vaccine injection site where they now encounter COVID protein from the vaccine in an entirely non-immunogenic setting; the RNA is long gone so even assumed inherent RNA immunogenicity is no longer relevant, the virus is gone and not in that area anyway so no danger signal there, and we have no idea how long the protein from the vaccine persists. What do the T cells do?

Maybe they clear that handful of cells as if they were virally infected and there is no issue other than a localized inflammation. Probably even. But, maybe they see the COVID protein in a new context, without immunogenicity, and they upregulate FOXP3 and become regulatory cells. Some of which become regulatory memory cells. And now we have a population of regulatory memory cells directed against COVID. I had a robust adaptive immune response and now I have tolerance.

Do I think this is likely? Not on a scale to make a difference, no. But, I do think this would happen on a cellular level. Do I think this would happen on a scale to affect the course of a secondary infection? Probably not. Definitely not in most patients. But I’m not remotely sure of that for all patients in the absence of data.

Should this stop people from being vaccinated? Again, absolutely not. Should it be monitored in the long term. Absolutely, yes. And it’s relatively easy to do so.

50

But why is this of particular concern with an mRNA vaccine?

The issue is that the presence of antigen without adjuvant may induce tolerance.

With an mRNA vaccine, the RNA is both the template for antigen production and the adjuvant that stimulates the innate immune response. So this directly conditions at least the initial production of antigen on the presence of adjuvant in the same cell.

Now, it could be true as you say that the antigen has a long half life, and hangs around for a long time after the mRNA has degraded. But if that’s the case, it’s a property of the spike protein, not the RNA. So the same potential for this problem is going to arise with a conventional approach if you inject spike protein with an adjuvant: the adjuvant may be metabolized before the spike protein.

I will go and dig out the Pfizer & Moderna research, but from what I remember reading, they have a well developed toolkit of derivitized nucleotides that they use to modulate immugenicity and rate of degradation of the mRNA construct for an optimum result. I’d be very surprised if they don’t also have data on the half life of the spike protein as part of this calculus.

51

A neutral (I hope not stupid) question: would this vaccine cause some normally occurring bacteria to produce the spike protein or is it only going to work on a human cell?

52

Two things.

First, if I inject both of us with 5 micrograms of COVID protein we both have 5 micrograms of COVID protein antigen. If I inject both of us with 5 micrograms of COVID RNA, we are both likely to get significantly different amounts of antigen which will affect the half life.

Second, if I’m injected with 5 micrograms of COVID protein, there is 5 micrograms of protein that will ever be available and once it’s gone, it’s gone. If I’m injected with 5 micrograms of COVID RNA, the first molecules of protein can go away, but there will be more made. It’s replenished unlike a protein vaccine. How much more and for how long we have no idea. That’s going to be not a factor of the persistence of the RNA and the turnover rate of the protein on the surface of cells. Which will depend on a million unpredictable things. Which cells are taking up the RNA, how much is getting into the nucleus of the cell, how much gets translated. These are factors that will vary a lot from patient to patient.

The window of antigen expression with an RNA vaccine is likely longer (though admittedly, this could be titrated to match a protein vaccine, but this would decrease immunogenicity - if we had any idea of the half life of the vaccine induced protein), more variable, and more persistent than a protein. So, you’re right this could be an issue with a protein as well, just for a much shorter and more predictable window of time.

53

No. Most bacteria have a tougher cell wall outside the lipid bilayer, the delivery particle cannot penetrate that. And bacterial ribosomes initiate translation of mRNA through binding to a specific sequence in the RNA, whereas eukaryotic ribosomes initiate translation from the 5’-cap. So although the nucleic acids and the basic principles of translation are similar across all life, a bacterial ribosome would not know what to do with eukaryotic message even if it got into the cell.

54

There goes my movie idea. Thanks! :grinning:

55

Some external commentery on ADE in mRNA vaccines:
https://blogs.sciencemag.org/pipeline/archives/2020/12/18/antibody-dependent-enhancement

56

While long-term possible complications of the vaccine cannot be know until years have passed, apparent long-term complications of the disease are well known and not pleasant. I suspect that almost everyone will either get the vaccine or get the disease. You pays your money and you takes your chance. Me, I will try to get the vaccine and ASAP. YMMV.

57

Wrong thread

58

Exactly what I am going to do. Retired 70 year old nurse.

59

When I hear about cells replicating things, I guess I worry about cancer more than immune system. Obviously, there’s no evidence that these vaccines will cause increased incidence of cancer in 20 or 30 or 50 years (because they wouldn’t be approved if there were) but has there been any research that rules it out?

I admit this is stupid, but if I am going to inject this in my kid, I gotta worry about the very long term. I’d be reassured if someone knowledgeable would tell me that’s silly in this case.

60

Yeah, I’m knowledgeable to tell you it’s silly in this case. Cells replicating a spike protein for a brief period of time is not really related to cells replicating to form new cells, which is what the replication we call “cancer” is. Your cells are metabolizing, and sucking up some stuff and spitting out (replicating) other stuff all the time.

There are certainly risks with the vaccine. It’s even possible that the vaccine (or the virus itself, or both) can somehow trigger cancer. But the vaccine making the cell “replicate” a protein is not related to cancer in any direct way.