7 ms·

I don’t understand why the innate immune response wouldn’t default to attacking an organism made of chiral molecules, since it attacks anything it doesn’t recog

I don’t understand why the innate immune response wouldn’t default to attacking an organism made of chiral molecules, since it attacks anything it doesn’t recognise. And while the adaptive immune response might not immediately recognise a novel organism, is there something that would prevent it ever adapting?

kragen 2y ago
Well, not anything. I have glass embedded in my foot which isn't being attacked, for example, and there are plenty of examples of biocompatible polymers, many of them already used in medical implants. (By the way, all organisms are made of chiral molecules; what we're talking about is reversing the chirality.) Some of the things the immune system uses to attack things, such as superoxide, would work fine on mirror organisms. Others, such as antibodies to existing organisms, wouldn't work at all. I don't know what the balance is.
Filligree 2y ago
I’m sure it would attack it, and it likely would even succeed. The problem is the chiral molecules would be difficult to clean up. You’d have this anti-life bacteria torn to pieces, yes, but then the pieces get stuck everywhere and potentially jam things. Personally—not a biologist—it doesn’t feel like a huge risk, given we accept threats such as microplastics which do much the same thing. However, it’s a completely unnecessary threat with essentially no upsides, and it wouldn’t be possible to undo once created.
- tw04 2y ago
  Do we really "accept" microplastics? It seems to me most scientists in the field are terrified of microplastics, while simultaneously acknowledging it's a problem that we almost assuredly can't realistically solve on any reasonable timescale. I'm confident if we had seen microplastics coming when we first started using plastics, science at least would have tried to prevent their use becoming as widespread as it has.
  - sitkack 2y ago
    Humanity knew very well that lead and mercury were highly toxic and yet only recently are they being phased out in widespread use. The Man Who Accidentally Killed The Most People In History https://www.youtube.com/watch?v=9sm1qxqdRyY https://www.youtube.com/watch?v=9sm1qxqdRyY Hundreds of millions of pounds of Glyphosate is spread across the entire globe. Scientists don't have much say in these things.
    - cj 2y ago
      Humans only respond to acute threats. As a society we don’t have a means of effectively responding to long-term threats. We seem to only care about the next 5-10 years. Our species is short sighted, but I suppose evolution will correct that, eventually.
      - deadbabe 2y ago
        Well the average remaining life expectancy of all adult humans currently alive is probably only a little more than 10 years so it makes sense.
        throwaway0123_5 2y ago
        Are you suggesting a massive collapse is likely in ~10 years?
        deadbabe 2y ago
        Why? You know how averages work?
        throwaway0123_5 2y ago
        Life expectancy and median age (didn't find average but I assume it is pretty close) were the first things I checked when I read your comment, but life expectancy globally is in the 70s and the median person about 30. I don't understand how the average person could have only a little more than 10 years left.
michaelmrose 2y ago
Stuff binds to other stuff because the magnetic domains and shape match up well enough. There is no way to effect something that attacks everything it doesn't recognize because a) there is no ooeration that represents not matching and b) if there was such a cell would be a short lived bomb that would blow up your body. You adaptive immune system learns to and antigen when a short lived immune cell is semi randomly generated that binds to it and becomes a longer lived cell. Presumably this could still happen but this normally takes days to happen. In between your inate immune system relies on being able to recognize a lot of existing antigens that are out there and common in attackers. Having the entire library of malicious life become magically unknown means that you are relying on only your adaptive immune system is available to contain the damage.
- f1shy 2y ago
  In biology is much much muuuuch more about physics as chemistry. Is all about the shapes of very big molecules.
- selimthegrim 2y ago
  There are already examples of immunosilent (to humans) lipids like in Moritella.
- dekhn 2y ago
  Magnetism does not play a role in binding in biology. The primary determinants of binding are: shape complementarity, electrostatic interactions, van der waals forces, and some amount of hard to explain entropy. (biomagnetism is a thing, but I'm not aware of any cases where binding occurs due to magnetic forces)
  - aeonik 2y ago
    I think they might have meant they are all geometrically defined EM interactions.

kragen 2y ago

Well, not anything. I have glass embedded in my foot which isn't being attacked, for example, and there are plenty of examples of biocompatible polymers, many of them already used in medical implants. (By the way, all organisms are made of chiral molecules; what we're talking about is reversing the chirality.) Some of the things the immune system uses to attack things, such as superoxide, would work fine on mirror organisms. Others, such as antibodies to existing organisms, wouldn't work at all. I don't know what the balance is.

Filligree 2y ago

I’m sure it would attack it, and it likely would even succeed. The problem is the chiral molecules would be difficult to clean up. You’d have this anti-life bacteria torn to pieces, yes, but then the pieces get stuck everywhere and potentially jam things. Personally—not a biologist—it doesn’t feel like a huge risk, given we accept threats such as microplastics which do much the same thing. However, it’s a completely unnecessary threat with essentially no upsides, and it wouldn’t be possible to undo once created.

tw04 2y ago
Do we really "accept" microplastics? It seems to me most scientists in the field are terrified of microplastics, while simultaneously acknowledging it's a problem that we almost assuredly can't realistically solve on any reasonable timescale. I'm confident if we had seen microplastics coming when we first started using plastics, science at least would have tried to prevent their use becoming as widespread as it has.
- sitkack 2y ago
  Humanity knew very well that lead and mercury were highly toxic and yet only recently are they being phased out in widespread use. The Man Who Accidentally Killed The Most People In History https://www.youtube.com/watch?v=9sm1qxqdRyY https://www.youtube.com/watch?v=9sm1qxqdRyY Hundreds of millions of pounds of Glyphosate is spread across the entire globe. Scientists don't have much say in these things.
  - cj 2y ago
    Humans only respond to acute threats. As a society we don’t have a means of effectively responding to long-term threats. We seem to only care about the next 5-10 years. Our species is short sighted, but I suppose evolution will correct that, eventually.
    - deadbabe 2y ago
      Well the average remaining life expectancy of all adult humans currently alive is probably only a little more than 10 years so it makes sense.
      - throwaway0123_5 2y ago
        Are you suggesting a massive collapse is likely in ~10 years?
        deadbabe 2y ago
        Why? You know how averages work?
        throwaway0123_5 2y ago
        Life expectancy and median age (didn't find average but I assume it is pretty close) were the first things I checked when I read your comment, but life expectancy globally is in the 70s and the median person about 30. I don't understand how the average person could have only a little more than 10 years left.

michaelmrose 2y ago

Stuff binds to other stuff because the magnetic domains and shape match up well enough. There is no way to effect something that attacks everything it doesn't recognize because a) there is no ooeration that represents not matching and b) if there was such a cell would be a short lived bomb that would blow up your body. You adaptive immune system learns to and antigen when a short lived immune cell is semi randomly generated that binds to it and becomes a longer lived cell. Presumably this could still happen but this normally takes days to happen. In between your inate immune system relies on being able to recognize a lot of existing antigens that are out there and common in attackers. Having the entire library of malicious life become magically unknown means that you are relying on only your adaptive immune system is available to contain the damage.

f1shy 2y ago
In biology is much much muuuuch more about physics as chemistry. Is all about the shapes of very big molecules.
selimthegrim 2y ago
There are already examples of immunosilent (to humans) lipids like in Moritella.
dekhn 2y ago
Magnetism does not play a role in binding in biology. The primary determinants of binding are: shape complementarity, electrostatic interactions, van der waals forces, and some amount of hard to explain entropy. (biomagnetism is a thing, but I'm not aware of any cases where binding occurs due to magnetic forces)
- aeonik 2y ago
  I think they might have meant they are all geometrically defined EM interactions.