
Adult immune systems ‘remember’ germs to which they’ve never been exposed (2013) - akbarnama
https://med.stanford.edu/news/all-news/2013/02/immune-systems-of-healthy-adults-remember-germs-to-which-theyve-never-been-exposed-stanford-study-finds.html
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worldvoyageur
I grew up on a farm. It was common knowledge that when a calf, or a lamb was
born they needed to get that first milk from their mom. The first milk looked
different and was called colostrum. Colostrum contained a large assortment of
antibodies from the mother that were transmitted to the newborn. If there was
some health issue, the mother died or the newborn couldn't drink, we had
colostrum in the freezer. If we didn't give it, the odds dropped dramatically
of the newborn making it more than a few months.

So, yes, mammals, including people, get immunities to germs they have not been
exposed to.

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Wowfunhappy
My understanding was that breast milk (at least in humans) gave the baby
antibodies, but not the ability to _create_ those antibodies. So, the effect
wouldn't last.

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sjwright
But still I would imagine that such antibodies would be exponentially more
valuable in the earliest moments of life, where it’s likely that the newborn
fist comes into contact with the mother’s fecal material and all of the
bacteria living on our skin.

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BurningFrog
Those are (mostly) good bacteria though.

Some theorize the baby _needs_ the mother's poop, to start it's own digestive
microbiome. It works that way in other species, but I don't know if it's more
than speculation for humans.

You also need a skin microbiome, but you can get that later.

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jacobush
I have heard reasoning that c-section babies could benefit from having some
given to them.

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hirundo
"...memory CD4s proliferated and otherwise became activated in response to
exposure to certain components of the influenza virus, but also to epitopes of
several different bacterial and protozoan microbes. This cross-reactivity
could explain why exposure to common bugs in the dirt and in our homes renders
us less susceptible to dangerous infectious agents."

So the CD4 is a key activated to fit a particular lock, but given the
imperfections of locks it fits a random assortment of others too. As we build
up a keychain of these we have a better chance to fit any random lock.

But why doesn't the larger keychain also increase the chances of auto-immune
diseases when they happen to fit our own locks? Or increase inflammation from
other benign microbes it fits? Seems like the metaphor needs work.

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nullc
> But why doesn't the larger keychain also increase the chances of auto-immune
> diseases, when they happen to fit our own locks?

The process that generates immune cells tests them for autoimmune reactivity
and aggressively culls ones that are.

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nomel
Could you provide the name for this, or something I could search for? This is
fascinating.

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rcthompson
Look up the function of the thymus in T-cell development and selection.

[https://en.wikipedia.org/wiki/Thymus#Function](https://en.wikipedia.org/wiki/Thymus#Function)

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abainbridge
Could someone add 2013 to the title? I just spent 15 minutes thinking I must
be a genius because I had already figured this out. Now I realise I read about
it already.

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bsoyka
I agree, bit confusing. I never read about it until now.

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jmalicki
William Petri is a wonderfully appropriate name for a professor of infectious
diseases.

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chadlavi
love nominative determinism

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techbio
There’s a term for this!

The orthodontist that adjusted my siblings braces was named Dr. Hurt (or some
homonym) and I’ve observed similar many times since.

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gowld
If you accept few will, it's an aptonym.

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techbio
I don't have a choice but to accept _free will_ :)

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hpoe
So I do not understand much about biology but could this effect explain why we
seem to have so many people test positive for anti-bodies on COVID-19 tests,
compared to other forms of testing?

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wh1t3n01s3
Only if the person tested is more than 100 years old (ie spanish flu
antibodies)

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romski
That was an influenza virus, this is a coronavirus they are completely
different. But to your point, there have been numerous flu pandemics since
1918

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chiefalchemist
“It may even provide an evolutionary clue about why kids eat dirt,” said
Davis. “The pre-existing immune memory of dangerous pathogens our immune
systems have never seen before might stem from our constant exposure to
ubiquitous, mostly harmless micro-organisms in soil and food and on our skin,
our doorknobs, our telephones and our iPod earbuds.”

Have there been studies on the effects of being too clean? Will short term
fear (e.g., Covid-19) hurt us in the long term?

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spacephysics
Would epigenetics from past ancestors explain this? [0]

[0] = [https://www.scientificamerican.com/article/fearful-
memories-...](https://www.scientificamerican.com/article/fearful-memories-
passed-down/)

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abainbridge
No. The article says newborns don't have these activated CD4 cells.

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isbwkisbakadqv
article doesn't provide any citation to the article it is summarizing...

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lomoramic
[https://www.cell.com/immunity/fulltext/S1074-7613(13)00052-6...](https://www.cell.com/immunity/fulltext/S1074-7613\(13\)00052-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS1074761313000526%3Fshowall%3Dtrue)

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koeng
Antibody production in vertebrates is an amazing example of an extremely
efficient directed evolution system within our own tissues.

There is some interesting work being done to mine antibodies from people who
have recovered from diseases and use those as a therapeutic medicine. Worked
great for Ebola, would also work for COVID-19, but scaling production is
really really hard (maybe some schlep blindness there)!

If I recall correctly, they pretty much put the gene for the anti-ebola
antibody into a plasmid in bacteria, then vacuumed those bacteria into
tobacco, which mated with the tobacco, which caused over-expression of the
antibody. Then, you grind up the plant, and purify the protein.

I'm interested in trying that out with my own blood - effectively making open
source antibodies for different diseases. I also know a few folks working on
DNA vaccination, which could have an interesting intersection.

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shireboy
How on earth do they know for sure someone has never been exposed to a germ?
Couldn’t it just be the antibodies were from very limited exposure?

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andi999
Can anybody recommenf two good books on immunology? One clear introductory and
one rearch level detailed?

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Cosi1125
I can only recommend one, but very good: How the Immune System Works by Lauren
Sompayrac
[https://www.goodreads.com/book/show/940153.How_the_Immune_Sy...](https://www.goodreads.com/book/show/940153.How_the_Immune_System_Works)

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acqq
(2013)

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hajderr
How is this relevant? I'm not into this field. The article is only from 2013.
So I can only relate it to Covid-19.

Thankful for any response

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downerending
I'm thinking Bloom Filters.

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Ozzie_osman
Could partly explain why it seems like covid-19 isn't hitting developing
nations as hard. They have more antibodies to other viruses. There's also the
theory that the tuberculosis vaccine (mandatory in many developing nations but
not in developed ones) helps too, and there are clinical trials going on to
confirm that.

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thedudeabides5
It's also warm and wet in many developing nations. Seen a couple pieces
suggesting COVID is relatively heat-phobic.

Would also jive with seasonality of the flu...

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yters
I graphed death rate by absolute latitude for countries with more than 1000
cases, and there is a clear trend. There is a bulge in the middle latitudes,
and dips toward the lower and higher latitudes. My guess is the virus doesn't
do well in hot climates, and people don't congregate much in very cold
climates.

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romski
It’s the spring in the northern hemisphere, it’s not cold anywhere in the US
or Europe. I don’t see how your conclusion is relevant

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coreyp_1
Yup not cold at all here in Indiana. Please disregard the snow that we had
earlier this week...

Lol. It's quite difficult (misguided) to generalize about an entire country!

