Genetically Engineered Spider Toxin Becomes A Vaccine
A Sydney funnel-web spiders rears up on its hind legs as a tube used to extract venom is placed nears its claws at the Australian Reptile Park at Gosford, 100 km (60 miles) north of Sydney. Credit:Reuters
Researchers have come up with an ingenious solution to the nuisance caused by spiders and their toxic venom.
By genetically modifying the spider toxin, researchers have now developed a vaccine. Since the genetically engineered version consists of three proteins, it is expected to provide protection against more than one type of toxin. Further, the new product does not have any side effects on the immunized animal which produces the vaccine. It is also supposed to be more effective than the crude venom from spiders. Tests on rabbits showed immune response similar to the entire toxin, but without any of the toxic side effects. The engineered version was protective against the poison from the L. intermedia and L. gaucho sub-species. The immunized rabbits showed protective effect after being tested with the Peruvian spider Loxosceles laeta venom (PLlv) and L. laeta venom from Brazil (BLlv). "In vitro assays with horse anti-loxoscelic antivenoms produced in Brazil and Peru demonstrated that these commercial antivenoms were efficient to inhibit the sphingomyelinase activity of PLlv and BLlv, " the investigators led by Dr. Chávez-Olortegui of the Departamento de Bioquímica e Imunologia, at the Universidade Federal de Minas Gerais (Brazil) write.
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"It's not easy taking venom from a spider, a snake or any other kind of venomous animal," said Chávez-Olortegui, in his interview with Eureka News. "With our new method, we would be able to engineer the proteins in the lab without having to isolate whole toxins from venom. This makes the whole process much safer."
"Existing anti-venoms are made of the pure toxins and can be harmful to people who take them. We wanted to develop a new way of protecting people from the effects of these spider bites, without having to suffer from side-effects."
The research is an advance over the current practice of using animals to generate the vaccines: administering the venom to animals, and taking the resulting antibodies for the serum. The genetic engineering approach obviates the need for animal experimentation and the consequent toxic effects animals are subjected to.
By identifying unique proteins or peptides and raising antibodies the researchers are able to neutralize some of the biological effects induced by crude spider venom, demonstrating a protection against the venom. The research paves the way for the development of therapeutic vaccines against spider venom, on a larger scale. Using similar genetic engineering approaches, the researchers led by Chávez-Olortegui have previously developed Peruvian anti-bothropic anti-venom against Bothrops andianus snake venom, and is currently in pre-clinical stages.