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Basis of Pfizer, Moderna, and AstraZeneca COVID Vaccines

cDNA reverse transcription transposable elements COVID vaccines

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#1 Template-Primer

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Posted 24 November 2020 - 08:21 PM

This is NOT a request for medical advice.

 
Am hoping that someone on this site with an extensive molecular biology background can explain how the Pfizer, Moderna, and AstraZeneca COVID vaccines work.
 
I know a little (very little) about molecular biology. Based on my understanding, if mRNA is introduced into a human cell, it can be reversed-transcribed into cDNA, which can insert itself into the host cell genome and remain there indefinitely. This process of reverse transcription and insertion would be carried out by the enzymes reverse transcriptase and integrate, which are found as part of transposable elements in the human genome. Again, the foregoing is based on my very limited understanding of molecular biology.
 
Might this cDNA be expressed at a much later time to produce COVID spike proteins years after coronavirus has receded as a health threat? What effect would this have on the person vaccinated? What other consequences might ensue from using a mRNA approach to vaccine design?
 
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#2 bob1

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Posted 18 December 2020 - 11:04 AM

Basically no - to get integration you have to have parts in the sequence to be inserted that match parts of the host genome, these would need to be flanking the expressed sequence for it to continue to be expressed. Even then, the cell is very good at recognizing non-self DNA and generally methylate it so that it can no longer function. Even with these targeting sequences, the rate of insertion into a host genome is extremely low (less than 1 cell/million for microgram quantities of DNA in actively dividing cell cultures), even with transfection techniques that ensure that >70% of cells will have DNA inserted into the cell (NOT genome). Note that the route of administration - injection into the muscle, is into a region not known for its active cell replication.

 

Note also that every time you get an infection with a virus, the virus enters the cell and releases its DNA or RNA, just like the vaccine does, yet we do not see these integrating into our genomes often, despite some of the viruses targeting actively replicating epithelial cells.

 

In addition, IIRC, reverse transcriptases, while relatively common in eukaryotic genomes, generally do not reverse transcribe mRNA, but are used to shuffle genetic components at recombination events. - Anyone with a better knowledge of this, feel free to chime in.

 

These are the Pfizer and Moderna vaccines. The AstraZeneca is an Adenovirus vector with expressed spike proteins on the surface, a completely different system.



#3 Trof

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Posted 03 January 2021 - 02:23 AM

I'm just getting a bit into that, so just few links.
About Pfizer.

Here is a site of the lipid nanoparticles manufacturer, shoud have info how about that.
https://acuitastx.com/

A bit of IT-like sequence explanation:
https://berthub.eu/a...pfizer-vaccine/

 

You can also start on Wikipedia sources:
https://en.wikipedia...iki/Tozinameran

As said, mRNA packed in LPN is just directly transcribed, only desined to look non-viral (uridine replaced by pseudouridine) and to produce spike proteins on it's surface and trigger immune response (though likely not a cytotoxic one, since there would be a foreign protein outside, but no suspicious cirus-like activity, that would trigger killing the producer cell, IMO). Then both B-lymfocytes and T-helpers are activated to create a stable production of Igs, finally ending with hopefully stable IgG production after a second dose.


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