Hacker News Reader

Comment by mabbo | Hacker News Reader

If there's such an easy biological mechanism to indicate "this one is fine", then I'm surprised it isn't being exploited by infectious agents already.

Imagine a virus that causes cells to also produce proteins that tell the immune system the virus is a friend.

View on HN

There are many such signals and they are already being exploited by pathogens. Such things are also exploited by tumors. That's why figuring out hard basic immunology problems like transplantation (while managing associated infections) will probably generate knowledge that is likely to help cure cancer, and vice versa. A lot of the time glycans (sugars) are a key part of what makes something look like self vs non-self.

Regulatory T cells and infection: a dangerous necessity https://www.nature.com/articles/nri2189

Sialic acid utilization by bacterial pathogens https://www.microbiologyresearch.org/content/journal/micro/1...

Hallmarks of glycosylation in cancer https://www.oncotarget.com/article/8155/text/

I seem to recall that this is a known "side effect" of measles where it removes many immunities if you catch it.

Here's a 2019 article, "Study suggests how measles depletes body’s immune memory"[0] which (despite the title) seems to quantify the percentage of antibody arsenal that is lost after a measles infection. Sadly, I haven't had luck finding resources to answer "by what mechanism does measles cause antibody memory to be lost?", but I've got a good thing to ponder for the weekend. Thanks. :)

[0] https://news.harvard.edu/gazette/story/2019/10/how-measles-w...

Here you go: https://asm.org/Articles/2019/May/Measles-and-Immune-Amnesia

Very short version: it infects the tissue that create the cells that contain or immune memory, replacing them with versions that only know about the measles virus. Sounds like it's not permanent, though the article doesn't make it clear whether it's recovery or re-learning.

Our immune system is quite aggressive with garbage collection and can picky about what pathogens it chooses to remember. This behaviour makes sense on the hypothesis that our immune system has a "storage limit" for immunities. It doesn't make sense if the immunity memory is unlimited.

(The reason why many vaccines require boosters is that without the repeat exposure, our immune system decides it doesn't need to remember about that particular pathogen.)

Also, HIV depletes your T cells

And SARS-CoV-2, unfortunately.

?? 99.9% of people recover just fine and surely they still have their T cells

How confident are you in your position? Literally 30 seconds spent searching: https://www.nature.com/articles/s41418-022-00936-x

I've only skimmed it, but doesn't the article you linked indicate that it is only true for severe/ life-threatening cases of COVID-19?

Doesn't matter, it shows that covid can deplete t-cells as claimed up-thread.

extreme cases of covid is not relevant for 99.9% of people so that's sufficiently close enough to say your claim is exaggerated. Sure, colds can kill too, but we don't treat them the same as Ebola.

The claim that a thing happens is not invalidated by it's relative frequency. You don't get to pretend lightning doesn't exist despite the relative rarity of people being hit by it.

It’s probably a waste of breath on this forum at this point, but look it up, and how long it takes even HIV infected individuals to become clinically immunodeficient.

Some gut parasites release immunosuppressants to protect themselves , it's also actively being traild on humans who suffer from autoimmune gut diseases

There already are diseases that hide from the immune system, things like hepatitis B, herpes, shingles.

It’s nothing new.

Could we vaccinate Herpes to forget how to latch on to cells?

Not really.

The current approach is to try and find an antigen on the herpes virus that the virus can't stop the immune system from recognizing.

Or use antivirals to stop the reproduction process, and the virus eventually dies. That's the approach with hepatitis C.

No. If you create a strain of a disease that is less persistent, it would obviously be wiped out almost instantly by basic natural selection.

Trypanosomas change their protein markers to hide from the immune system. My recollection is this is why you can't create a vaccine for them.

Reply on news.ycombinator.com