An engineered protein could one day be used to create vaccines against deadly venoms like that of the brown recluse © Shutterstock
Posted on 05/14/2013 10:13:08 PM PDT by neverdem
Brazilian researchers have engineered a protein that should make producing antivenoms to treat spider bites both cheaper and simpler. The protein may also pave the way for a vaccine, as it can prime the immune system to cancel out the worst effects of the spider venom.
Venomous spiders inflict pain, injury and even death in several parts of the world. Those bitten often need to be treated with an antivenom, a serum containing specific animal antibodies against the venom toxins. Antivenoms are currently produced by injecting the venom into an animal to provoke an immune response. But a single spider only produces a tiny amount of venom, so extracting enough to produce antivenoms on an industrial scale is a tricky business.
‘In Brazil, more than 40,000 spiders per year are used to make antivenoms,’ says lead author Carlos Chavez-Olortegui of the Federal University of Minas Gerais, Brazil, ‘and the injection of these extremely toxic substances harms the animals involved.’
His group have been working on reaper spiders (Loxosceles sp.), which bite thousands of people every year in Brazil. They constructed a vaccine-like protein that allows them to make antivenom without having to extract venom from spiders and inject it into animals. The protein is non-toxic, but has a distinctive structure that is recognised by the immune system. To make it, the team had to isolate three antigen peptides from a Loxosceles venom toxin called LiD1. They then used molecular cloning to construct a single protein containing all three components.
Rabbits injected with the protein produced antibodies against LiD1, and those that had been immunised were protected from spider venom. Chavez-Olortegui says the protein could make antivenom production easier and safer, and is a promising candidate for a vaccine that could be used to protect people against bites. ‘Using this non-toxic protein is clearly a good option,’ he says, ‘and the same approach could be taken with other venomous species.’
Ken Winkel, director of the Australian Venom Research Unit in Melbourne, says that whether the work translates into new antivenoms will depend on cost effectiveness. ‘This is certainly an interesting approach,’ he notes. ‘As technology improves it may be that this strategy becomes more generalised in antivenom development. But it has limited applications at this stage, due to the lack of knowledge about the antigens of different venoms.’
C Chavez-Olortegui et al, Vaccine, 2013, DOI: 10.1016/j.vaccine.2013.03.048
An engineered protein could one day be used to create vaccines against deadly venoms like that of the brown recluse © Shutterstock
A bad one that is probably of more interest to brazilians is the phoneutria.
I met a fellow who had a healed brown recluse bite in his upper arm. It was at least 2 inches across and cratered at least 1/4 inch. Nasty stuff.
FReepmail me if you want on or off my combined microbiology/immunology ping list.
Back in 91...during my three week stay after a bad gall bladder/liver/pancreas issue....my first roommate was an HVAC guy with a fiddleback wound right above his right elbow. He arrived around 11 pm...I remember clearly the orthopedic telling him that if the 1,000 buck a bag antibiotics and surgery didn’t work...he might lose his arm below the elbow. The wound was dime sized.
At 7 am next morn...right after I was given a pre op “Happy Shot” before being wheeled down to OR...in my haze of high I remember the HVAC guy say “Check this out roomie”....and my eyes fixed on what was now at least a silver dollar sized hole which provided a very nice view of his elbow joint as he flexed it up and down.
It took my mind off the 60/40 odds the bookies were laying on my survival after surgery for a minute.
His arm and I both made it through our ordeals. From that point on...I kept a very keen eye out for them.
Yup, the flesh just liquefied and melted away about 1/4 to 3/8 of an inch deep.
And I was lucky compared to what has happened to some people.
A brown recluse bit a friend of mine. She was screwed up for YEARS. She not only had a large piece of flesh above her knee removed, but suffered through nausea and sweating every time she exerted herself due to the venom being taken up by her fat cells.
A friend of mine died from a Brown recluse spider; heart failure.
He lived in central Indiana.
.
Odd. When my pancreas exploded I ended up with a roomie who was a black widow bite recipient. He was on the mend when I left, but it was touch and go for a while.
Indeed. Several years ago my sister was bitten on the foot by a brown recluse spider. The poison rapidly ran up her entire left leg. The damage was so severe at that one point the surgeons were on the verge of amputating her entire leg. But at the last minute one of the doctors had an idea of how to save her leg. And the treatment worked.
Funny how life works sometimes. ;)
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.