What is the difference between a vaccine using RNA vs DNA?

Discussion in 'Biology & Genetics' started by Dennis Tate, May 9, 2021.

  1. Dennis Tate Valued Senior Member

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    1,154
    My question is sincere.....
    at this moment my wife and I are both discussing making an appointment to take either the Pfizer or the Moderna vaccine but.......

    .... we are not entirely thrilled with vaccines that do alter our RNA.

    We do know that a vaccine that alters our RNA is very different than if it actually changed our DNA somehow.
     
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  3. Overcast Registered Member

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    Here is my understanding of this...

    Pfizer and Moderna are both mRNA vaccines. They do not change your DNA but rather introduce a "spike protein" to your cells that makes it harder for the virus to attach itself. mRNA is a relatively recent technique in immunology that has been in use for at least the past 10+ years. This technique for delivery has suggested to be the future of vaccines as the development time is shorter than that of a traditional vaccine. The downside is that these vaccines require intense refrigeration, and haven't been used on this scale before.

    Janssen (Johnson+Johnson) and AstraZenaca vaccines use a virus vector (not a Coranavirus) to deliver the spike protein. Because the RNA is being carried inside virus, they do not require the high refrigeration requirements of the Pfizer or Moderna vaccines. These vaccines are closer to what we would consider to be a "traditional vaccine", but aren't entirely the same. Traditional vaccines have usually carried a weakened form of the virus they are immunizing against, allowing the subject to develop antibodies. That's not the case here.

    I'm sure other people here can weigh in as well.
     
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  5. sculptor Valued Senior Member

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    questions
    once you have the "spike protein" in your cells
    is that a permanent change
    is that a change that will be inheritable?
     
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  7. exchemist Valued Senior Member

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    Not quite. What is introduced to the body - by the BioNTech/Pfizer, Moderna, Oxford/AstraZeneca and J&J vaccines is not the spike protein but a segment of mRNA that causes the body's own cells to make the spike protein, in situ, as it were. This is just as would happen if a real virus had taken over the cell and hijacked it to make viruses, except that it is only making one bit.

    And the spike protein produced does not make it harder for the virus to attach itself. What it does is stimulate the immune system of the body to make antibodies to attack and neutralise this new "foreign" protein.

    The BioNTech/Pfizer and Moderna vaccines encapsulate the mRNA in a synthetic lipid nanoparticles, which is a new technology. The Oxford/AstraZeneca and J&J vaccines put the mRNA into harmless viruses, as you describe.
     
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  8. exchemist Valued Senior Member

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    No. It is mRNA that is introduced, not the spike protein itself. This causes the cells in your body to make the virus spike protein for a while, long enough to stimulate an immune response. But the spike protein is quickly neutralised by the immune system once it has been activated. And the mRNA has only a transient existence and disapppears.

    The only thing left behind is the immune response: antibodies and a memory of the foreign protein in the immune memory cells, which allows them to make more antibodies quickly, if they come across the same protein again.

    This immune memory is how all vaccines work.
     
  9. KUMAR5 Registered Senior Member

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    923
    "There are several types of vaccines, including:

    • Inactivated vaccines
    • Live-attenuated vaccines
    • Messenger RNA (mRNA) vaccines
    • Subunit, recombinant, polysaccharide, and conjugate vaccines
    • Toxoid vaccines
    • Viral vector vaccines"
    Still, how inactivated whole virus or its other part is able to infect same cells like intact active virus does?
    If it is able to infect cells, will those cells still die or danaged?
     
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  10. billvon Valued Senior Member

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    20,163
    They don't alter your RNA. They add new RNA.
    They don't add a spike protein to your cells, nor does it make your cells harder for the virus to attach.

    What they DO do is use mRNA to cause some of your cells to express one of the proteins in the spike. This is expressed on each cell via your MHC's. Your immune system sees that foreign protein, attacks it (and the cell) and remembers the protein in the future. If you get a SARS-CoV-2 infection in the future, your immune system recognizes the foreign viruses rapidly and attacks them.
    Those are adenovirus based vaccines. They do not use RNA; they are expressed in DNA, similar to most viruses. The adenoviruses themselves infect cells; these cells then again express components of the spike protein that SARS-CoV-2 uses, and primes the immune system to fight them.
     
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  11. KUMAR5 Registered Senior Member

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    923
    I think, it is the process of development of immunological memory or memory in B Memory cells. Following questions still arise:-
    1. In both cases, mRNA or adenovirus DNA has to enter/infect same cells which SAR-COV-2 virus infects to express spike protein. If so, how such mRNA or Adenovirus is able to infect same cells? They sre not same as live virus.

    2. Imfection to many cells, may be at par or more than natural infection, may be needed to get simlar or more immunity. If this happen due to vaccination than will those infected cells by vaccinated material still be got killed or damaged?

    3. If we anticipate immunological memory development by vaccination, how then specific antibodies post vaccination are consistently detected for many months?
     
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  12. billvon Valued Senior Member

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    20,163
    No. In 99.9999% of the cases, it is NOT the same cells.
    No, not really. Vaccine dosages are calibrated to produce a robust immune response. Some vaccines need two injections to get a good response. (The second one has much more effect, since the immune system has been "primed" by the first one.)
    Because antibodies last a long time, and our body produces them for a while even after the infection goes away. From an energy/nutrition standpoint they are fairly cheap to make.
     
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  13. KUMAR5 Registered Senior Member

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    923
    Thanks.

    If they are not same or simlar cells, how we can get soecific immunological memory or specific antibodies from vaccines as we get from natural infection? If they are non specific then how they will be effective to same vitus?

    Shoud we not need to get more infection expression from vaccines to get more robust immune response than natural infection? One dose is also only advised in some vaccine.

    [ Quote]Because antibodies last a long time, and our body produces them for a while even after the infection goes away. From an energy/nutrition standpoint they are fairly cheap to make.[/QUOTE]

    Long term antibodies are needed to for secondary immune response. Few also anticipate these for long term protection from re-infection. I am bit unclear when immunological memory got developed post infection or post vaccination, what is the purpose of maintsining antibodies for long term unless remanant latent virus or its traces are left for long post infection or post vaccination?

    4. One more question to my last post. Can infection/entry of changed genome to cells lead to creation of changed or new type variant vituses?
     
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  14. Dennis Tate Valued Senior Member

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    1,154
    I thank you all for these explanations......

    I was rather impressed by what I was hearing about what seems to be happening in Israel.

    https://www.bbc.com/news/health-56722186

    Covid: 'Israel may be reaching herd immunity'

    What has been accomplished in Israel is one of the reasons that we are leaning toward Pfizer.

    Israel celebrates 5 millionth coronavirus vaccination
    https://www.ctvnews.ca/health/coron...5-millionth-coronavirus-vaccination-1.5337844

     
    Last edited: May 11, 2021
  15. RainbowSingularity Valued Senior Member

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    6,670
    just go on amazon & buy the sputnik Russian one instead if you prefer.

    is that legal ?

    surely that must be legal in the usa ?(in the usa where all health care is private to give people liberty & choice & democracy yadda yadda bullshitbullshit)
    patient choice unless it sounds like a socialist in which case pay ridiculous amounts of money to the fda to ban it & bury it in law suites.
    now where did that flash mob of anti vaxers go i need some more subscribers
    irony
     
    Last edited: May 11, 2021
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  16. exchemist Valued Senior Member

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    I repeat: all vaccines work by stimulating the immune memory system. All vaccines.
     
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  17. exchemist Valued Senior Member

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    Thanks for the correction on the Oxford/AstraZeneca and J&J vaccines. I had thought these too used RNA, but indeed they seem to use DNA.
     
  18. KUMAR5 Registered Senior Member

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    923
    Does it mean, content of all vaccines serve as antigens for memory B cells due to which they acquire immunological memory and secrete antibodies?
     
  19. exchemist Valued Senior Member

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    10,799
    It means all vaccines work by stimulating this series of mechanisms: https://en.wikipedia.org/wiki/Immunological_memory

    You will see there is more to it than just B cells.
     
  20. KUMAR5 Registered Senior Member

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    923
    Yes Memory T cells are also related. However it is bit unclear whether T Cells also act as memory cells or as effector cells
    stimulated by Memory B Cells. Look from your link:

    ".
    Development of immunological memory
    The course of secondary immune response is similar to primary immune response. After the memory B cell recognizes the antigen it presents the peptide: MHC II complex to nearby effector T cells. That leads to activation of these cells and rapid proliferation of cells. "
     
  21. billvon Valued Senior Member

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    20,163
    Antibodies recognize proteins, not cells. Antibodies cannot easily get inside cells. So to help out, cells have these structures called MHC's (major histocompatibility complexes) that present internal peptides to the world outside the cell.

    Antibodies drift by these structures. Do they see only autologous peptides? (i.e. parts of proteins normally expressed by cells) Then they pass them by and ignore them. Do they see peptides from viral protein synthesis? Then they attack that cell and destroy it, because a virus is using it to replicate.

    So in the future, antibodies will not look at a cell and say "hey, that cell has been infected before.) All they do is look at the MHC. If it contains those fragments of the spike protein, it attacks the cell*. If it does NOT see the fragments, it leaves it alone.
    (* Note that antibodies alone do not finish off the cell. Generally they signal one of the many killer leukocytes, like killer T-cells, to get involved.)

    Correct. And they both work in _slightly_ different ways. In mRNA vaccines, there is nothing to recognize and attack until cells start expressing that protein, because your immune system completely ignores the slightly modified RNA. (It does not see it as RNA due to a clever replacement of one base pair.) However, in adenovirus based vaccines, the immune system _can_ recognize the free viruses, and that contributes to the response.

    The reason we know they work is not that we decided that they do based on any of the above. The reason we know they work is they have been tested, and they do indeed prevent serious illness ~95% of the time.

    Nope. You can have zero antibodies (IgM) for a given antigen and still mount a robust secondary immune response due to the action of memory B cells. Of course, a non-zero number of antibodies will speed up the response significantly.

    It is worth noting that there are several different kinds of antibodies. The ones most people are familiar with are the IgM antibodies; in an illustration showing antibodies attacking a virus, they are generally showing IgM antibodies. They are large and complex and very specific, and are thus a little more fragile.

    IgG antibodies are smaller and much longer lived. They are not created until well into the immune response and are not as specific - but they do last longer.

    So if you get reinfected immediately, IgM antibodies go to work right away.

    If you get reinfected a while later (say 2 years) IgG antibodies provide some initial defense until the memory B cells start producing more antibodies.

    If you get reinfected decades later, then your memory B cells have to produce antibodies before the secondary response gets going.

    All of which is why you are most protected right after either vaccination or getting over an infection.
    Again, since mRNA vaccines do not change the genome of the cell - no, it cannot.

    HOWEVER, frequent use of any mitigation in a population where the disease is endemic can indeed lead to resistance. This is most commonly seen in antibiotics, but can also occur with vaccines. That's why it's essential to finish the entire course of antibiotics, so you can wipe out all the bacteria and not leave any to evolve resistance. That's also why it's critical to get Re below 1 quickly, to wipe out the virus quickly rather than leave large pools of infection to evolve resistance.
     
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  22. Dennis Tate Valued Senior Member

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    1,154

    I was told something very interesting about the vaccines just today by a good friend........

    I made the statement that my wife and I are discussing whether or not to get the Pfizer vaccine and we stated that the vaccines were rushed..... and we are not totally thrilled with them but.........

    since my wife's parents already got their Pfizer shot and had no really nasty reaction..........

    this of course has us taking Pfizer more seriously.

    Anyway... my friend replied that a doctor in British Colombia stated that these vaccines actually were being prepared for the last twenty years........

    ... as a vaccine for a previous version of COVID was being researched........

    so these vaccines were NOT as rushed as I had assumed even as of yesterday?!
     
  23. KUMAR5 Registered Senior Member

    Messages:
    923
    Thanks a lot.
    How igG antibodies are non specific(as you told)?
    It is estimated Covid immunity either post infection or post vaccination will last in about 6 months or so. But when immunological memory can exist for years or decades, how 6 months or so is estimated for Covid 19?
    Btw, whether getting immunity to reinfection is 100% post infection but 70 to 90% post vaccination?
     
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