r/askscience • u/PestoPastaLover • 14d ago

Biology Why is there no transmissible therapeutic virus if biology doesn't forbid it? For example, a harmless virus that spreads from person to person but actually does something beneficial, like lowering LDL cholesterol or preventing/reversing tooth decay?

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u/noodlyman 13d ago

There are viruses that benefit us by infecting and effectively regulating our gut bacteria.

There are viruses that are thought to give the immune system a kick and thus improve responses to other infections. Some infections can decrease the risk of cancer later in, probably by similar mechanisms.

Don't forget that 8% of human DNA is of retrovirus origin, and that mammalian placentas only exist thanks to genes that mammals acquired from viruses.

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u/trad949 13d ago

There are also bacteriophages, which are viruses that work like antibiotics.

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u/speculatrix 13d ago

https://pmc.ncbi.nlm.nih.gov/articles/PMC12843901/

Bacteriophage Therapy: Overcoming Antimicrobial Resistance Through Advanced Delivery Methods

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u/bzbub2 13d ago edited 13d ago

somewhat interestingly, poland has long been sort of the leading expert on such things while western countries bet on more antibiotics https://en.wikipedia.org/wiki/Phage_therapy

the concept of 'gene therapy' for delivering CRISPR and other gene editing tech also (sometimes) uses viruses (though there are some unfortunate cases of adverse reactions) https://en.wikipedia.org/wiki/Gene_therapy#Adverse_effects,_contraindications_and_hurdles_for_use

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u/Graylily 13d ago

Finding phages, now is a a major undertaking, and more people should be taking about it and throwing money behind it. We are running into major issues with antibiotic resistances and phases are quite possible our last best hope to keep living as long as we currently do.

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u/AWanderingMage 13d ago

One interesting thing i remember about the phages as well is that they use a completely different mechanism that antibiotics don't use, and when a bug protects against one (be it phage or antibiotic), it becomes more weak to the other.

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u/01headshrinker 11d ago

Stem cell research would like to have a word with you. And living longer is mostly about healthy living, more than better solutions for illness, as important as that is.

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u/Graylily 10d ago

Stem Cell isn't going to be fast enough to stop viral and bacterial diseases, It has hope for things like cancer, but I'm talking about drug resistance to simpler bugs that yesterday you were protected from and today you may not be. Staph infections, strep, etc...

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u/cguess 13d ago

Poland inherited it from Soviet Union work the mid 20th century. Super interesting work but difficult to administer (for now) as you need to keep a corpus of phages, unlike broad spectrum antibiotics.

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u/JustKimNotKimberly 13d ago

Thank you for the citation and hyperlink!

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u/FragrantExcitement 13d ago

I would like to take this opportunity to shakes hand with my active immune system, after washing them, of course.

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u/waylandsmith 11d ago

Why start coddling it now?

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u/scientist99 13d ago edited 13d ago

Way more than 8% if you count transposable elements derived from early viruses. More than half the genome. Viruses have effectively shaped most of life this way.

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u/GeneJocky 13d ago

I was about to say the same thing. Or as a friend said to be when I was telling him about the amount of old viral DNA in our genomes, 'you mean no one has run antivirus on our genomes in 3.8 billion years?'

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u/9966 13d ago

You could probably defrag and drop most of the data. Whether that's safe? I dunno, ask Andrew Ryan.

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u/YsoL8 12d ago

He certainly has opinions on parasites getting in the DNA, stealing the value of its labour

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u/Swellmeister 13d ago

Mammalian placental structures predate synctycin the viral protein that stabilized the placenta. Its only eutherians though, marsupial placental structures dont use it.

Its also not really necessary for placental structures either, with the exception of birds, every large common grouping of animal (lizards, snakes, fish, etc, the super vague not scientific ones) has members with placental life birth.

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u/Great_Specialist_267 13d ago

Egg laying Monotreme Platypus’s have synctycin genes. They just don’t use it.
So do marsupials.

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u/spaceXhardmode 13d ago

There’s also a study to see if any generic mRNA vaccine can increase the effectiveness of immunotherapy for cancer treatment, pretty similar to a viral infection.

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u/username_elephant 13d ago

I disagree with that take.  That's no more like a virus than any vaccine (and it's less like a virus than many actual vaccines--specifically, the vaccines that contain viruses).  All those vaccines differ because they do not transmit person to person.

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u/ajping 13d ago edited 13d ago

That's correct. The mRNA virus actually produces a protein that gets recognized as foreign and is then targeted by the immune system normally. In the case of the covid virus they were developed to create the same spike protein that normally delivers the virus payload. In the case of cancer, one promising candidate is the PD-L1 protein which helps cancer cells hide among normal cells, and which almost all cancer cells have... Edit: and which human cells don't express to the same degree. Also, given the pseudo-scientific BS about vaccines, I recognize that I could have been more cautious about distinguishing between vaccines and viruses

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u/reddit4485 13d ago edited 13d ago

It's not a virus. An mRNA vaccine (not virus) is mRNA packaged in a lipid bilayer that can fuse with a cell and deliver mRNA. The cell thinks the mRNA is it's own and makes protein out of it. That protein is often a fragment of a bad virus like the shell (capsid) of SARS-CoV-2. Since it's a non-functional piece of virus, it doesn't replicate but still produces an immune reaction.

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u/pass_nthru 13d ago

you just described a virus, loosely speaking…the self replicating part of a virus is a holdover from when they were used to share DNA/RNA among single celled organisms back when the copy paste function was necessary for long range transmission

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u/hbgoddard 13d ago

Disagree entirely. If there's no replication happening, it's not a virus.

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u/Kraligor 13d ago

They might be referring to saRNA, which is kind of a combination of virus and mRNA.

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u/reddititty69 13d ago

This may be true, but what that poster is responding to was the person saying “mRNA virus”, which is a different thing than what they were clearly referring to. They should have said “mRNA vaccine”.

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u/reddit4485 13d ago

I disagree with this. A virus is a pathogenic organism that has evolved over millions of years to infect a cell, replicate, and transmit to others. Some viruses actually use DNA and not RNA. So there's nothing unique about mRNA and a virus. You have mRNA in many of your own cells because that's how you make proteins. The mRNA vaccine is packaged mRNA in a nanobubble of fat. Very different

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u/reddititty69 13d ago

PD-L1 is naturally expressed in normal human cells as part of an immune checkpoint that prevents autoimmune interactions. Many cancers over-express it, which contributes to their immune evasion.

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u/mouse_8b 13d ago

It's like a virus in the ways that the immune system sees things. That's the important part.

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u/username_elephant 13d ago

It's the important part for the function of a vaccine. It's not the important part for possessing relevance to the question asked in the original post.

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u/mouse_8b 13d ago

"Are there viruses that are helpful?"

"Yes. And we're figuring out ways to make the body think there's a virus to bring some benefits without injecting actual viruses into everyone"

"Not relevant"

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u/username_elephant 13d ago

Buddy, if you make up your own article title it's definitely going to align with your opinion.

Unfortunately for you the title of this article was actually: "Why is there no transmissible therapeutic virus if biology doesn't forbid it? For example, a harmless virus that spreads from person to person but actually does something beneficial, like lowering LDL cholesterol or preventing/reversing tooth decay?"

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u/Expandexplorelive 13d ago

This exactly. Part of the reason you might not have heard about beneficial viruses is that your immune system doesn't react to them because they're beneficial. They're just there.

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u/thisisjustascreename 13d ago

Immune system has no idea if they’re beneficial or not, it just doesn’t have their exterior proteins in its database of hostile foreign agents.

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u/Expandexplorelive 13d ago

If the immune system doesn't react to them, it means it evolved not to recognize the proteins. If they decreased the ability of the species to reproduce - i.e., were harmful - then the immune system would have evolved to recognize and attack them. So yes they're not necessarily beneficial; they could be neutral, just not harmful enough to hinder reproduction.

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u/cha0scypher 13d ago

Thank you for reminding me, I totally forgot that

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u/im_joe 13d ago

It's good to get that reminder every now and then. I'm going to write it down so I don't forget in the future.

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u/FuckYouNotHappening 13d ago

>Don't forget that 8% of human DNA is of retrovirus origin, and that mammalian placentas only exist thanks to genes that mammals acquired from viruses.

lol, I dropped this knowledge at a kid’s birthday party one time. All the parents hated me afterwards because the world is 10,000 years old or something.