[tjrgergw]

> It has long been known that people can form defenses and thus antibodies against viruses. But antibodies can also develop against polyethylene glycol (PEG), a substance used in cosmetics, food and medicine.

People can develop antibodies against things which are not foreign micro-organisms. TIL.

(Obvious once you think about it. What you really develop antibodies to are proteins on the surface of micro-organisms)

Well, talk about a worldview-changing moment.

[hwillis]

> People can develop antibodies against things which are not foreign micro-organisms. TIL.

Well yeah- that's how many (most?) resistance to toxins works. When you are given pit viper antivenom, it's literally a bunch of sheep antibodies that attach to the venom molecules and neutralize them and/or make them easier to get rid of.

You do the same thing for novel toxins as you develop a tolerance to them. Alcohol and peroxide have specific enzymes that are produced to break them down, but the immune system is responsible for a ton of stuff.

I am not an expert but I do know it's heinously complex- there are tons of different pathways that are activated by a combination of foreign substances and/or different types of cellular damage (not to mention location in the body). Anaphylactic allergies are controlled by different types of antibodies in different cells that react to different types of damage, normal allergies are a whole other thing, blood antibodies are yet another (multiple types!) of thing...

Biologists are amazing. It seems like picking diamonds off the beach. The book documenting the (public) operation of a new CPU is 10k+ pages long, but a single mammalian cell (taking up <<.001% of the area) makes that CPU look like a joke.

[didgeoridoo]

I don’t think the news here is that PEG can be targeted by antibodies (research companies have been manufacturing anti-PEG antibodies for decades), but that anti-PEG arises naturally (and frequently!) in the adaptive immune system.

Might be a good biomarker to adjust dosing and estimated pharmacokinetics of PEGylated drugs; it might make sense to take another look at PEG-based therapies that failed Phase II/III with this new finding in mind?

[thfuran]

>but that anti-PEG arises naturally (and frequently!) in the adaptive immune system.

According to the PEG wiki, that has apparently been known for decades.

[HPsquared]

In other words, allergies.

[hwillis]

Yes but no. Allergies are a very particular reaction- you don't get allergy symptoms when you're sick. They're predominantly IgE (immunoglobulin E) which is a detector antibody rather than a neutralizing antibody (although those terms aren't really favored now). IgE activates a body response like anaphylaxis.

The antibodies in this study are IgG (the "normal" antibody) and IgM. In this case, these antibodies latch onto and neutralize/clean up the antigen. They cause much less of an immune system activation, and can act like a passive defense.

TL;DR: allergies are a subset of antibodies for substances, and in this case the antibodies found were non-allergenic.

[throwawaymaths]

PEG is not a protein. And you can definitely get antibodies against anything. There's an idiot researcher trying to get people to make antibodies against cocaine.

The bonkers thing about this is that adding PEG is supposed to be a strategy to get things to evade the immune system.

[chpatrick]

Isn't that what allergies are?