by Alexis Hubaud
figures by Anna Maurer

Vaccination is key to preventing disease and has been a major advance in public health to eradicate epidemics like smallpox or polio. Vaccines work by mimicking an infectious agent, and by doing so, train our bodies to respond more rapidly and effectively against them. A new class of vaccines, “RNA vaccines”, has recently been developed. RNA vaccines rely on a different way to mimic infection. Compared to previous vaccines, this method is more robust, more versatile, and yet, equally efficient. Therefore, the RNA vaccine technology holds great promise to prevent and treat a wide range of diseases, such as influenza or cancer.

Have you heard about RNA vaccines? This technology recently made the news when the Bill & Melinda Gates Foundation invested $53 million in the German company, CureVac, which specializes in the development of these vaccines [1]. In this article, we will discuss how RNA vaccines work, their main advantages compared to traditional vaccines, and their applications in diseases such as influenza and cancer.

How do RNA-based vaccines work?

Vaccination is the process in which substances called antigens are introduced artificially into the body to stimulate the immune system, the set of cells that protects the body against infections [2,3]. Those antigens are generally infectious agents – pathogens – that have been inactivated by heat or chemical treatment so that they will not cause disease, or they can also be purified proteins from the pathogens. Exposing the body to antigens leads to the production of molecules specifically directed against them, called antibodies. Antibodies create a memory of a specific pathogen (“acquired immunity”) and enable a more rapid and efficient response to a real infection with an active pathogen.

Vaccination has been central in diminishing or eradicating multiple infectious diseases, such as smallpox or polio. However, producing vaccines is a long and complex process, and it has been difficult to implement vaccines against certain pathogens. Thus, designing new vaccines remains a major challenge for public health. To answer this challenge, there have been many improvements to designing vaccines, such as using computational prediction. Development of nucleotide vaccines based on DNA, and the related molecule RNA, is another promising area of progress in the field [4].

In each cell of a living organism, DNA is the molecule that contains the genetic information of the organism [5]. It is composed of a series of four building blocks, whose sequence gives the instructions to fabricate proteins. This process requires a transient intermediary called messenger RNA that carries the genetic information to the cell machinery responsible for protein synthesis. As an analogy, one can see the DNA as a cook book in a library: the recipe is stored here but cannot be used. The commis, or chef’s assistant, first makes a copy (the RNA) of a specific recipe and brings it to the kitchen. The information is now ready-to-use by the chef, who can add the ingredients in the order specified by the recipe and create a cake (the protein).

Figure 1: RNA vaccine technology. An RNA is injected in the body (left). This RNA encodes the information to produce the antigen, which is a protein from a pathogen, that will stimulate the immune system. Inside the cells, the RNA is used to synthesize the antigen, which is exposed to the cell surface (middle). Then, a subset of immune system cells recognizes the antigen and trigger an immune response (direct response and long-term memory) (right).

For a classical vaccine, the antigen is introduced in the body to produce an immune response. However, in the case of DNA- or RNA-based vaccines, no antigen is introduced, only the RNA or DNA containing the genetic information to produce the antigen. That is, for this specific class of vaccines, introduction of DNA and RNA provides the instructions to the body to produce the antigen itself (Figure 1). They can be injected in various ways (under the skin, in the vein or in lymph nodes) and then they can enter our body’s cells. Those cells will use the RNA sequence of the antigen to synthesize the protein [2,6]. After this step, the mechanism is similar to classical vaccines: the antigen is presented at the surface of a subset of cells and triggers the activation of specific cells of the immune system (Figure 2).

The ways in which DNA and RNA vaccines work are similar in many ways, and some of the common steps are described above. However, RNA vaccines have some distinct advantages. One is that RNA-based vaccines appear to perform better than DNA-based vaccines. Another is that they are also safer, as injection of RNA presents no risk of disrupting the cell’s natural DNA sequence. To continue our kitchen analogy, disruption from DNA is like inserting a foreign ingredient in an existing recipe, which can change the resulting dish [2].  Injecting RNA, on the other hand, is like temporarily adding a new recipe in the cook book while keeping old ones untouched, and therefore will not result in surprising changes to existing recipes.

Figure 2: Disease prevention. Vaccination with RNA induces a primary response (top) by instructing the body’s cells to produce an antigen that is presented to the immune system. This activates specific cells, which create a memory for this antigen. Later, when the real pathogen is present (bottom), those cells recognize the same antigen and react rapidly and strongly against the infectious agent (secondary response).

How are they produced?

With the considerable progress in DNA sequencing, it has become relatively easy to determine the genome sequence of pathogens. RNA can thus be produced in vitro, i.e. outside the cells, using a DNA template containing the sequence of a specific antigen. Creating a RNA vaccine also requires some engineering of the RNA to achieve a strong expression of the antigen [4,6].

This is a much simpler process than the culture of virus in eggs. Egg cultures, the more common way of producing vaccines, can provoke allergic reactions; the in vitro production of RNA avoids this possibility. Producing RNA vaccines is also less expensive than producing the full antigen protein [4,6,7].

Another advantage is that the production of RNA-based vaccines is more rapid compared to production of traditional vaccines. This rapid production could be a major advantage in face of sudden pandemics. Moreover, RNA-based vaccines may be effective against pandemics because they also provide more flexibility to prevent or treat pathogens that are rapidly evolving [8,9]. For instance, influenza vaccines have to be tailored each year to specific strains that are most likely to cause disease in the coming season. However, these forecasts have not always been accurate, such as during the winter of 2014-2015, making the influenza vaccine less protective. The World Health Organization estimates it takes approximately five to six months to produce an influenza vaccine, whereas the company CureVac claims that RNA-based vaccines could be manufactured in less than two months at a lower production cost, making it possible to respond to epidemics even as they develop. Therefore, RNA-based vaccines offer a comparatively simple and rapid solution to unpredictable, rapidly evolving pathogens.

While injection of simple RNA can elicit an immune response, RNAs in this form are prone to a rapid degradation. Current vaccines are fragile and can lose their efficiency when exposed at freezing or high temperatures, and must be stored at 35-45°F (2-8°C)[4,6,10]. Thus, preserving the cold chain is a major hurdle for the implementation of vaccine campaign. Fortunately, scientists have found ways to combat this RNA degradation. For instance, they can change the sequence of RNA to make it much easier to store. Furthermore, other molecules can be added to bind the RNA and protect it. Such engineering enables the storage of RNA vaccines at room temperature for at least 18 months. This feature precludes the necessity of maintaining the cold chain, making RNA vaccines particularly practical for developing countries.

What is the current state of the research?

This new exciting technology could be applied to many diseases, and pharmaceutical companies are making major investments in that area. RNA vaccines are still at the pre-clinical or clinical stage, but have yielded promising results. Below, we will explore two examples with the most advanced results: RNA vaccines to treat cancer and RNA vaccines to prevent influenza.

In the field of cancer immunotherapy, “cancer vaccines” take advantage of the expression of specific markers by cancer cells to direct the immune response and attack the tumor. RNA vaccines against prostate cancer, melanoma, and lung cancer (non-small cell lung cancer) are currently in clinical trials. For instance, six different RNAs against proteins produced in excess in tumor cells were used to formulate a vaccine against lung cancer. By taking advantage of the flexibility of RNA vaccine production, scientists can thus produce a vaccine with different antigens which is consequently better at targeting the tumor cells [11].  In the case of the prostate cancer vaccine, a preliminary study showed that injection of those RNAs foster an immune response in most of the patients. Whether this production of antibodies is sufficient to slow down the tumor progression remain to be determined.

Interestingly, because of the versatility of RNA vaccines, they could be tailored to fit the antigen repertoire of each patient tumor. Tumor cells are very different between patients, and this variability is an ongoing an issue for cancer treatment.  An ongoing clinical trial is testing whether RNA vaccines may be effective for addressing variability in melanoma patients: in the trial, each tumor was first sequenced to identify its unique antigen repertoire, and then, a RNA vaccine is tailored to each tumor (Figure 3). This study shows that RNA vaccines could play a major role in this growing field of “personalized medicine” [7]. Moreover, these tailored, on-demand vaccines are practical – the company BioNTech claims that it could be manufactured in 5 months [12]).

Figure 3: Disease treatment (example of personalized cancer immunotherapy). The DNA from the tumor cells is first analyzed (top) to identify antigens specific to the patient’s tumor (Antigens A,B,C). Secondly (middle), a personalized vaccine comprising the specific RNAs for those antigens found in the analysis is injected to direct the attack of the immune system against the tumor (bottom).

RNA vaccines are also being developed to prevent infectious diseases. A vaccine against rabies is currently in clinical trials, while vaccines against influenza, HIV or tuberculosis are still at the research stage. Published results with the influenza vaccine [9] showed promising protection in mice. Indeed, injection of RNA coding for different proteins of the influenza virus induced the production of antibodies, and when the mice were later exposed to the virus, all survived. Similar immune response was observed in ferrets and pigs. All these observations in animals point to a potential use in humans.

The field of RNA vaccines is still nascent. However, their production is flexible and rapid, and recent studies indicate they could be effective against a wide range of infectious diseases and cancers. While their clinical potential in humans remains to be firmly established, RNA vaccines appear to be a promising technology worth watching out for.

Alexis Hubaud is a PhD student in Developmental Biology working at the Brigham and Women’s Hospital / Harvard Medical School

References

[1] Press statement from the Bill and Melinda Gates Foundation and CureVac
http://www.gatesfoundation.org/Media-Center/Press-Releases/2015/03/CureVac-Collaboration
[2] Introductory video about vaccination http://www.pbs.org/wgbh/nova/body/immunity-and-vaccines.html
[3] Vaccination ingredients from the NHS (UK National Health Service) website http://www.nhs.uk/conditions/vaccinations/pages/vaccine-ingredients.aspx
[4] Review about RNA vaccines- Schlake et al. RNA Biology (2012) 9(11):1319-1330
[5] Introductory video about synthesis of proteins from DNA and RNA http://www.pbs.org/wgbh/nova/body/cellular-factory.html
[6] Review about the CureVac vaccine – Kallen et al., Human Vaccines and Immunotherapeutics (2013) 9(10):2263-2276
[7] Review about RNA-based therapies – Sahin et al., Nat Rev Drug Disc (2014) 13 :759-780
[8] News article about the use of RNA vaccine against Influenza
Making a Flu Vaccine Without the Virus – http://news.sciencemag.org/2012/11/making-flu-vaccine-without-virus
[9] Scientific article on a RNA vaccine against influenza
Petsch et al. Nat Biotech (2012) 30(12):1210-1216
[10] Website from the company CureVac, which specializes in RNA vaccine http://www.curevac.com/
[11] Scientific article on a RNA vaccine against non-small cell lung cancer – Sebastian et al., BMC Cancer (2014) 14 :748
[12] Website from the company BioNTech, which specializes in RNA vaccine http://www.biontech.de/

30 thoughts on “RNA vaccines: a novel technology to prevent and treat disease

  1. Thanks to the great minds behind this RNA vaccine development technology.

    I am a master’s student (MSc. Molecular Biology and Biotechnology) from Makerere University- Uganda. I am in my final year (Doing research) and I would like to be trained in this field (RNA vaccine development technology) so that Uganda can also participate in this new technology.

    I would wish to get a mentor in this field of research.

    Thank you.

    1. How could it? DNA –> RNA –> protein (aka the virus’ weapon against the cell). mRNA won’t enter the nucleus. They interact with cell structures only in cytoplasm, outside nucleus. Of course, this begs the question: why won’t foreign mRNA agents be killed by the body before they can enter our protein making factories?

      1. It sounds more like another virus, but instead of generating a full copy of it’s self, it just penetrates the cell membrane, like a virus and instructs the cell to make antigens. Antigens are pieces of the virus you want to stop, not the RNA virus/vaccine. The immune system is supposed to pick up on cells that have been destroyed by creating antigens and use that to ‘learn’ a response to the virus you want to stop.
        It all sounds good, but there’s little data on how well these work in mass populations. One risk is, could another, 3rd virus use the cell penetration mechanism and combine with it to produce a new virus that is self replicating and makes the antigen for the 2nd? Very new tech, needs a lot of testing before it’s ready for mass inoculation, I do not see it being ready for SARS-ncov-2 . But RNA vaccine seems like a good way to produce antigen in vitro, much less risk that way.

    1. Well, here they are talking about not using dna probably do to a chance of hybridization to the genome. However, RNA won’t do that, especially when we use mRNA, mRNA are just messengers and the tell the ribosomes what to make.
      Normal vaccines usually use a dead version and antigens from the virus you want to prevent. And when the body comes in contact with them it triggers a small immune response BUT there is no real threat since the virus isn’t actually there.

  2. Why are these mRNA not used to produce the antigens outside the human body prior to injection? Is it not unethical to be injecting people with foreign RNA that may become integrated into the genetic material of humans after the synthesis of the other strand?

  3. What’s to prevent the mRNA from entering germline cells? It seems risky to rush into human trials.

    1. Are you aware that viruses enter cells and produce their proteins by making mRNA? The advantage of Moderna’s approach over any sort of live virus vaccine is that Moderna’s just includes the mRNA, without including the rest of the virus.

  4. Yes, the mRNA sounds fantastic as soon as you realize that we are playing with genetic material. This is no joke!! And to think that the WHO and Bill Gates want to use this type of vaccine for Covid should worry all humanity.

    1. Exactly! Bill Gates (who, by the way, has no medical qualifications to justify his obsession with vaccines) stands to make a ton of money from a Covid vaccine. Reading articles like this and others (from the Rockefeller Foundation for example) from the past couple decades makes it clear that there was a plan in place to bring about a pandemic, with carefully laid-out “solutions” to the pandemic. Ultimately, we’re talking about mingling something foreign with our DNA. I can’t see how this could end well.

      1. It would probably be wise not to comment on the risks of mRNA vaccine development technology here, or any other science article unless you are an expert in this research. Concerning the latest popularpandemic conspiracy theory – The Gates Foundation (and all other foundations) are a by product of our own economic systems which are currently being used to create these these mega-billionaires. This is the result of allowing unlimited campaign dollars. Some of these mega-billionaires are actually interested in solving world problems – but if we want to have more influence over them, we need to change the tax system to recover, or divert the tax-exempt dollars that are flowing to them… https://nonprofitquarterly.org/is-the-gates-foundation-out-of-control/

        1. These are good questions. This is a dangerous practice.
          What qualifies an “expert”? 3 years of microbiology, 4? I have more microbio then is required by nurses. That said these comments are very good questions.
          Being that this is not a natural route of things, and GMOing is kinda like a chainsaw to do a paper cut out, the process on much of this is actually quite sloppy at the micro level.
          Think of DNA as a very complex janga tower. Think of scientists as ppl who want to replace blocks with an new color of block for purposes we need not get into.
          They can hypothesis about how they can do things but risks are always there. Think of the topple as any of unintended outcomes like a deadly autoimmune response, stimulation of long term self replicating cancerous cells, over all body contaminantion and many unforeseen side effects like to gonads and reproductive sideeffects.

          We do not see alot of mammal test subject information on this. Why is that?

          If we go back to creek and watson, the two who won the race to map DNA structure, we have a total shoot from the hip, get out the tinkertoys approach. Which was fine when we were in theorizing, but now we have real time applications to actual living ppl with this “lets see what happens approach” on a cold less deadly then the flu or chickenpox even.

          This is a goldengoose for profit when we have actual drugs or elements that remove the symptoms that are deadly.

          People should be researching treatment more then anything.
          The greatest trend to cancer is paralleled with vaccine use. The studies on this are very buried as big companies of pharma effect other big companies like Google. We just saw a 5 or 6 hour blacklist of companies where even if u typed a domain name direct results were nill.
          Yippy and other non-bias search engines are out propagated and never reach much public. Wikipedia has bias moderators who impose their idologies no matter hiw correct or incorrect. Just compare the historic record of what Mussolini defined as fascism to the 2008 on rendition. They are 2 different things for a political purpose.

        2. Event 201…Practicing the PR to make sure they could maximize profits during the next Pandemic that started two weeks later.

      2. Jen, Bill Gates id a true technologist: his interest in vaccines needs no medical qualifications. It is not he who applies the science of medicine to developing medical innovations. Instead, he delivers cash from his and Melinda’s grand store of almost $110 billion to fund research by people and institutions who have the education, skill and training to develop treatments and cures for diseases that plague human beings all over the Earth. The Bill and Melinda Gates foundation holds almost half of their wealth and is second only to Warren Buffett in funding humanitarian projects. When the Gate’s foundation produces a “miracle” treatment of cure through the efforts of a for profit institution, the profits accrue to the foundation, which uses them to further its.
        I can understand how observation of other wealthy entities, such as the Walton’s who donate less that 1% of their combined $140 billion to philanthropy might sour the casual observer on the philanthropy of the ultra- rich, but the Gate’s and the Walton’s, among others, do spend their wealth, or more accurately, the proceeds of their wealth on philanthropy. Surely, if you had control over a hundred billion or more dollars, you would do the same, rather than spend it on personal gain as the Walton’s or in advancing political caused as do the Koch Brothers?

        1. I wouldn’t call Gates a philanthropist. Just because someone labels poison as vitamins doesn’t make it so. All his NGOs push agendas, twisted from what the names allude. Gates make the original notsee eugenicists seem small time. Gates is banned in nations like India and in Africa because of the negative effects of his vax “philanthropy” of experimental practices.
          He was never voted in any government position, he has no authority just money and mal intent.
          Just because some functions witnessed in the human experience allude many who lack the mental development of certain aspects doesn’t mean it doesn’t exist. Referring to quantum influences and observations of conscience that is factual from experience to many. I.e. remote viewing telepathy and communication with non-human intelligence via thought. Many of these experiments threaten this natural abilities as they target certain genes that effect the mind, bombard us with millimeter waves.
          To those whom never nurtured repair of dialogue free thinking, not momentary but continuous, these subjects allude them greatly. Their perspectives are gravely handicapped.
          The greatest arguement is “proof”. Proove to me you see blue as I see blue. No one can. Proof is in practice. Laziness and ego are the enemy of that. Its self inflicted chosen ignorance backed by apathy of justice when put against ego.
          My job is not to prove or disprove but to point directions to research on your own. Much of lives lessons we know can not be learned through advice but personal trial and error unfortunately.

          1. It is not true that Bill Gates or his foundation was banned or kicked out of India. I suggest you try Google to find the truth about that story.

  5. I’d like to know if this mRNA method cannot be used to eradicate malaria that has been killing millions in Africa and Asia and creating unethical wealth for pharmaceutical conglomerates ?

  6. First, Bill Gates does not want or need anyones money, thats just plain stupid. The mere interest on his already aquired money is more than hundreds of millions of usa dollars every day. If you don’t or won’t trust science, then please stop using your phones and computers and believe the world is flat, that the plague derives from bad air, and believe that sperm are little babies.

    1. That is quite an ignorant thing to suggest. The study of existances’ observations a.k.a. science, is not a thing to believe in. Its everchanging. To believe in it at anyone state is to have obsolete beliefs because its always evolving. It is an ignorant gaslight to infer someone is against science for the most part. A mode used to attack another persons credibility, to kill the messenger so to speak, of what could be facts that are unpopular to the one hearing and gaslighting.
      I don’t just know bio, i know electronics at the most basic levels. How to make a capacitor and how it works for example. How quartz are imprinted and can be used to trigger memory (kinda like music can) and how the “science” in that can be witnessed in use of microSD cards even.
      There are not two opposing worlds of faith vs. Science. No. There is one world based on experience and observation. And faith and science are facets of that experience that do not contradict in anyway. It is the ego that conflicts or causes blindspots, deadends of thought trains for the convenience of the thinker.
      In the end it is the blind faith of ones Ego or just the ego itself that creates limitations of science.
      Science is always contradictory to itself we learn and observe. Always finding exceptions to rules and new factors unforeseen to send us back to the drawing board.
      People like gates are very dangerous, playing god over millions, with very limited knowledge. Remember his wealth was created by ripping off the author of Dirty OS, with his theft renamed it MsDos.
      The cost of mistakes by these actions of rna manipulations to DNA replication in humans can long surpass our lifetimes.
      What entitles the small tiny mind of any one of the right to dabble like that? Its at a level of one person having access to the red button of nuclear annihilation.
      Life is delicate. We have gained powers that surpass our mental capabilities of controlling the broad range of effects to our actions. GMO released in the wild is just one example of this abomination.
      Nature and the human experience has been around atleast 180000 years we can observe. Do you think this last 11600 years is the first cycle of civilization?
      Science denier don’t exist. Ego maniacs do.

    2. Gates wants not money but a post human world he of biotech transhumans without the masses of natural humans getting in his way. He wants what money cannot buy, more power then he already has.

  7. I don’t quite understand how this works on cancer cells.
    If the cancer cells are already exposing the antigens on the surface of the cell, why doesn’ t the immune system build an immunity and attack the tumors.
    What’s special about the antigen presenting cells that causes the immune cells to attack the tumor?

    1. Great question. The immune system has a ton of built-in checks and balances, to make sure that it does not become inappropriately activated (aka to make sure it doesn’t start attacking our own bodies, causing autoimmunity). One way that the immune system is kept in check is by co-stimulatory molecules — these are proteins on the surface of antigen presenting cells (but NOT on other cells, like cancer cells) that are required to fully activate an immune cell (more specifically, I’m referring to T cells here). So, if the immune system “sees” antigens on cancer cells, it will not kill them because antigen alone is insufficient to fully activate T cells. However, if these immune cells had previously “seen” antigen presented by antigen presenting cells, and at the same time encountered the requisite co-stimulatory molecules, they would be fully activated and capable of killing cancer cells on site, based on the presence of antigen alone. This video gives a nice summary.

      Hope this helps!

      1. Great explanation.

        So now explain the mechanism behind those whose immune systems do react outside of theory causing them autoimmune issues for life from a vaccine.
        What, why, how, & possibly when (timing of vaccine) does this happen?
        Why can’t vaccine scientists/researchers pinpoint the catalyst for these outcomes?

  8. SITNFlash, I appreciated your explanation and link to the excellent video. One of my questions regarding the Moderna vaccine trials and others based on tRNA, is whether there is a risk that the cells which incorporate the tRNA and manufacture antigens against SARS-CoV-2 might later become targets of the cellular immune system, setting up an autoimmune reaction. It sounds from your knowledgeable comments that this is felt to be unlikely and hasn’t been seen so far in animal and human trials.

    Thanks much!

    1. I don’t think we yet have a good understanding of the possible adverse effects. They can include inflammation, or autoimmune reactions.

  9. Interesting technology. I was wondering how long the mRNA persists in the cells, and continues to produce the antigen protein? And since most allergic responses are to proteins, what is the likelihood of someone developing an allergic response to the protein being produced?

Leave a Reply

Your email address will not be published. Required fields are marked *