

World's first plastic antibody works in mice - bshep
http://www.newscientist.com/article/dn19031-worlds-first-plastic-antibody-works-in-mice.html

======
phren0logy
Man, that is amazingly cool. Does this have implications for other problems
that have to this point been limited by the difficulties of predicting the
outcome of protein folding?

------
ahk
Nice! Hoping to see the "no known antidote exists" tag disappear by the next
decade or so.

~~~
jballanc
Well, not to be a downer, but there are a number of caveats to be attached to
this discovery. First, melittin is over 7.5 kDa which, while small for a
protein, is still much, much larger than your typical household toxin. It is
also larger than the smallest molecules that antibodies can be trained
against.

Second, the interactions here appear to be entirely steric (that means
size/shape related). One of the advantages of natural antibodies is that they
can bind their targets via H-bonding, ionic interactions, van der Waals
interactions, and hydrophobic interactions in addition to steric interactions.

Third, clearance by the liver runs the risk of just having all of the toxin
concentrated in the liver, and it's not clear that the toxins will remain
bound to the bead until they are inactivated. Certainly, if we're talking
about a snake-venom which is a neurotoxin, and the "down-side" to taking this
and not dying is that you need a liver transplant, I think it would still be
useful, but this is not any sort of panacea I would think.

 _Edit_ : Also, it seems like the "imprinting" would require a fairly large
interaction surface with the target molecule. This means that its probably not
even very useful for molecular biology work, since natural antibodies can
distinguish between proteins with very small differences and only require
half-a-dozen or so amino acids for a match. Really, I think the lesson of this
article should be just how amazingly cool natural antibodies are, and that
it's taken until now to _maybe_ come up with something that could _possibly_
replace one of these uses.

~~~
ars
> clearance by the liver runs the risk of just having all of the toxin
> concentrated in the liver

Could you bind the toxins, then do a full body blood transfusion?

~~~
jballanc
Well, my training is as a biochemist, not a doctor, but my understanding is
that complete transfusions are extremely difficult or outright impossible
(there are a _lot_ of tiny little capillaries for things to get stuck in...).
Not to mention that the liver is really good at what it does, and it would
probably have soaked up most everything by the time you got to the hospital.

The real concern is not that it ends up in the liver, but that the plastic
antibodies don't bind as tightly as a natural antibody so that, once in the
liver, the toxins slowly "leak" out and poison the liver.

Honestly, we've gotten really, really good at manufacturing antibodies against
almost anything. Antibodies are a mainstay of modern biomedical research.
Sure, they're expensive, but other than cost I don't see anything that plastic
antibodies could do that natural antibody can't (and even in terms of cost, if
you need one molecule of target to serve as the "stamp" for each plastic
antibody, these are probably going to be _more_ expensive since, once you've
made the initial antibody, scaling up natural antibodies is mostly a solved
problem.

~~~
alex_stoddard
I think the term antibody here is mostly hype. The plastic nano-particles
don't act as antibodies beyond being specific for binding the toxin protein.
It is still a cool technology demonstration but "antibody" overstates the
case. To quote the article:

"However, Holliger doubts whether they could perform other important functions
of natural antibodies, such as priming the body's immune system to fight
future infections. Unlike natural antibodies, they are not equipped to
communicate with other cells and components of the immune system"

------
kiba
Yes, it's nice and all that it works in mice.

But does it work in the human body?

