Prions and Immunity questions*

[lilmamba17]

Ok so firstly,

A person sufferring from a prion disease undergoes an operation in the area where infectious prions are known. What is the best way to treat the surgical equipment after the operation. Explain

I said: Prions are insensitive to high temperatures like normal proteins. However at extremes they can be eradicated. Therefore the best way to treat the surgical equipment is by autoclaving them at extremely high temperature and pressure

The solutions however suggested to destroy the equipment. Is this true?

ALSO:
A protein from M tuberculosis is injected into the skin of the forearm
In terms of immunity, what is the extracted protein given in an injection called?

I said it was a vector but apparently its a foreign antigens. Is there a difference?


Thanks

[Truck]

Autoclaving them for 1hour at that super high temp., I think it's like 167 degrees or something, should be correct as that's enough to denature them.

[Russ]

My first thought was to dispose of/destroy them because prions are pretty good at surviving autoclaves.

The purified MTB protein is a foreign antigen. It's an antigen because it triggers an immune response (what vaccination is designed to do) and it's foreign because it doesn't arise within the person. A vector is responsible for transmitting a disease (eg Anopheles mosquito and malaria)

[lilmamba17]

Yeah i thought that too, but then again its safe to go with destroying them

That makes sense, althought why isn't it a vector? Because they are using it to in an injection to trigger an immune response, or are you saying that a vector is only in the case of bacteria/viruses?

Thanks for the help btw

[TrueLight]

well its to me it sounds a bit wishy washy...in here http://docs.google.com/viewer?a=v&q=cache:8gV8IXfqjGYJ:www.unc.edu/depts/spice/dis/ICHE-2010-Feb-p107.pdf+how+to+sterilize+prion&hl=en&gl=au&pid=bl&srcid=ADGEESjVmXfTgfYHAshcodotoAxeje-JfHm97yTGW-y_aPSwe6jFV57hFGYPnc44A7YceNTyoX6ICOrNT-5-7P2s5IaKWYfouTu9LW7x7KFJXjyHIj2zpGIuTBxotBHKu6uXadNfE9j6&sig=AHIEtbR26iW07mNPoblm4k3caqoBXohvZw... it says results in partial or complete loss of infectivity. they are resistent to sterilization techniques but they do have guidelines to disinfect and sterilize prion contaminated equipment

a vector is like an organism that transmits a pathogen... a protein is not that

[lilmamba17]

Yeah see that book also says autoclave.

Alright cool thank you

[slothpomba]

You generally want to err on the side of caution with prions. If you infect the patient say with Golden Staph or something like that at least you can treat them but once you "infect" them with prions, there is really not much you can do for them at all. They're pretty much dead at that point, its all down hill from there. As far as i know there's nothing available to treat prion diseases at all. So, even if there's a small chance of infecting someone, tiny chance, its a lot better to just destroy the equipment.

Just to reiterate what i said above, if you infect them with some other disease you can probably treat it but once you "infect" them with prions, they're pretty much more or less done for. So, yeah it might cost a bit to replace the equipment (you wouldn't have to do this often anyway, prion diseases are pretty rare) but it's a lot better than even having a small chance at fatally infecting someone.

[lilmamba17]

Just to reiterate what i said above, if you infect them with some other disease you can probably treat it but once you "infect" them with prions, they're pretty much more or less done for. So, yeah it might cost a bit to replace the equipment (you wouldn't have to do this often anyway, prion diseases are pretty rare) but it's a lot better than even having a small chance at fatally infecting someone.

true that thanks

[slothpomba]

I just read about this mineral the other day being used in photosynthesis experiments and solar cells but i did further reading... turns out it can also kill prions http://www.sciencedaily.com/releases/2009/01/090114142028.htm but this is very cutting edge, doubt its relevant to vce bio.

[lilmamba17]

this might be similar to the chemical my teacher was telling me about. apparently if you apply some chemical as part of sterilization it can remove any infecting prions. although ill be safe and go with either destroy or incubate at high pressure and temp

[Truck]

I just read about this mineral the other day being used in photosynthesis experiments and solar cells but i did further reading... turns out it can also kill prions http://www.sciencedaily.com/releases/2009/01/090114142028.htm but this is very cutting edge, doubt its relevant to vce bio.

Out of curiosity, how does this mineral differentiate between prions and normal proteins?

[shinny]

I just read about this mineral the other day being used in photosynthesis experiments and solar cells but i did further reading... turns out it can also kill prions http://www.sciencedaily.com/releases/2009/01/090114142028.htm but this is very cutting edge, doubt its relevant to vce bio.

Out of curiosity, how does this mineral differentiate between prions and normal proteins?

I'm pretty sure it can't, hence why it's being promoted as a potential sterilisation agent rather than medical treatment for active prion disease.

[slothpomba]

I did a little bit of reading and it seems they're not entirely sure. I saw the phrase "It degrades...x " a fair bit. I think it has something to do with it being a strong oxidant (there are stronger ones but this one is of interest because its in soil, where animals which would get prion diseases eat their food, live most of their lives, ect) and its ability to form complexes with prions.

Managed to pick out this phrase "These data are consistent with the hypothesis that Δ-MnO2 degrades PrPTSE by breaking the polypeptide backbone of the protein, but do not exclude the possibility that Δ-MnO2 also alters amino acid side chains." - http://jgv.sgmjournals.org/cgi/content/full/90/1/275 .

It actually does break down the prion in some way because they did immunological tests and it was no longer infectious or as infectious.

(Edit: Yeah, the molecule wouldn't really know whether its a prion its attacking or not. Since they're pretty much more or less the same as regular proteins, most reactions thatd break down prions would have to break down proteins. If you give this to a patient it'd probably kill them but you could make a solution of it and bathe surgical tools in it maybe but i don't think that will become a popular protocol, since its infintely safer to throw out the equipment rather than try sterilize it, no matter how good this stuff is. A lot more research is needed on this as well.)

If you want more you can always look on Google Scholar(Click here) if you're really interested but it might be a bit hard to understand.